0001193125-26-221661 | 10-Q | XBRL Viewer

Equity (Tables)

3 Months Ended

Mar. 31, 2026

Summary of Fair Value of Common Warrants Prior to and Immediately After Exercise Price Adjustment, were Estimated Using Black-Scholes Option-Pricing Model Assumptions

The fair value of the common warrants prior to and immediately after the exercise price adjustment, were estimated using the Black-Scholes option-pricing model with the following assumptions:


		January 23, 2026

Exercise price		$19.01-$11.70
Expected volatility		178.49%
Risk-free interest rate		3.53%
Expected average life of warrants		4.5

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2026	Dec. 31, 2025
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	15,000,000	15,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	1,203,753	997,830
Common stock, shares outstanding	1,203,753	997,830

Segment Information - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2026 USD ($) Segment	Mar. 31, 2025 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments \| Segment	1
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]	srt:ChiefExecutiveOfficerMember
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description	The CODM assesses performance for the novel oncology therapeutics segment and decides how to allocate resources based on net loss that also is reported on the income statement as consolidated net loss. The measure of segment assets is reported on the balance sheet as cash and cash equivalents.The Company has not generated any product revenue in the current period and expects to continue to incur significant expenses and operating losses for the foreseeable future as we advance our product candidates through all stages of development and clinical trials. As such, the CODM uses cash forecast models in deciding how to invest into the novel oncology therapeutics segment. Such cash forecast models are reviewed to assess the entity-wide operating results and performance. Net loss is used to monitor budget versus actual results. Monitoring budgeted versus actual results, net cash used in operating activities for the period and cash on hand are used in assessing performance of the segment.
Net cash used in operating activities \| $	$ 7,965	$ 6,575

Collaboration Agreements	3 Months Ended
Mar. 31, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration Agreements	Note 2. Collaboration Agreements Alligator Bioscience AB On July 20, 2017, our wholly owned subsidiary Aptevo Research and Development LLC (“Aptevo R&D”), entered into a collaboration and option agreement (the “Collaboration Agreement”) with Alligator Bioscience AB (“Alligator”), pursuant to which Aptevo and Alligator have been collaboratively developing ALG.APV-527, a first-in-class bispecific antibody candidate simultaneously targeting 4-1BB (CD137), a member of the TNFR superfamily of a costimulatory receptor found on activated T cells, and 5T4, a tumor antigen widely overexpressed in a number of different types of cancer. We assessed the arrangement in accordance with ASC 606 – Revenue Recognition (“ASC 606”) and concluded that the contract counterparty, Alligator, is not a customer. As such the arrangement is not in the scope of ASC 606 and is instead treated as a collaborative agreement under ASC 808 – Collaborative Arrangements (ASC 808). Both Aptevo and Alligator are active participants in the development of ALG.APV-527 and are exposed to significant risks and rewards under the Collaboration Agreement. Amounts owed to us for Alligator's share of development costs incurred by the Company are recorded as a reduction of research and development expense under ASC 730 – Research and Development in the period the costs are incurred. For the three months ended March 31, 2026 and 2025, we recorded approximately $0.04 million and $0.1 million, which represents our 50% cost share, in our research and development expense related to the Collaboration Agreement, respectively.

Collaboration Agreements

3 Months Ended

Mar. 31, 2026

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Collaboration Agreements

Note 2. Collaboration Agreements

Alligator Bioscience AB

On July 20, 2017, our wholly owned subsidiary Aptevo Research and Development LLC (“Aptevo R&D”), entered into a collaboration and option agreement (the “Collaboration Agreement”) with Alligator Bioscience AB (“Alligator”), pursuant to which Aptevo and Alligator have been collaboratively developing ALG.APV-527, a first-in-class bispecific antibody candidate simultaneously targeting 4-1BB (CD137), a member of the TNFR superfamily of a costimulatory receptor found on activated T cells, and 5T4, a tumor antigen widely overexpressed in a number of different types of cancer.

We assessed the arrangement in accordance with ASC 606 – Revenue Recognition (“ASC 606”) and concluded that the contract counterparty, Alligator, is not a customer. As such the arrangement is not in the scope of ASC 606 and is instead treated as a collaborative agreement under ASC 808 – Collaborative Arrangements (ASC 808). Both Aptevo and Alligator are active participants in the development of ALG.APV-527 and are exposed to significant risks and rewards under the Collaboration Agreement. Amounts owed to us for Alligator's share of development costs incurred by the Company are recorded as a reduction of research and development expense under ASC 730 – Research and Development in the period the costs are incurred. For the three months ended

March 31, 2026 and 2025, we recorded approximately $0.04 million and $0.1 million, which represents our 50% cost share, in our research and development expense related to the Collaboration Agreement, respectively.

Equity

3 Months Ended

Mar. 31, 2026

Equity [Abstract]

Equity

Note 8. Equity

2023 and 2024 Common Warrants

As of March 31, 2026, there were 3 outstanding warrants issued in 2023 with exercise prices ranging from $136,555.20 to $363,369.30 per share and 4,645 outstanding warrants issued in 2024 with exercise prices ranging from $428.40 to $17,892 per share.

2025 Equity Offerings and Common Warrants

On April 4, 2025, we completed a registered direct offering and a concurrent private placement (the “April 4, 2025 Offering”), in which we issued 4,901 shares of common stock and accompanying common warrants to purchase up to an aggregate of 9,803 shares of common stock at an exercise price of $428.40 per share for a combined offering price of $428.40 per share and accompanying common warrants. The common warrants became immediately exercisable following the date of stockholder approval on May 14, 2025 and will expire in May 2030. We received $2.1 million in gross proceeds less total issuance costs of $0.2 million. In connection with the April 4, 2025 Offering, we also agreed to amend certain existing warrants that were previously issued on December 12, 2024 to purchase up to 4,575 shares of common stock and had an exercise price of $3,430.80 per share, and reduced the exercise price of these warrants to $428.40 per share. The Company recognized the $0.6 million modification date incremental value of the modified warrants as compared to the original warrants as a non-cash issuance cost of the April 4, 2025 Offering. Given the common warrants were equity classified, the modified fair value of existing common warrants to purchase common stock has been accounted for in additional paid-in capital as an equity cost because the modification was done in order to raise equity in conjunction with the April 4, 2025 Offering. As of March 31, 2026, we have 9,812 common warrants outstanding in connection with the April 4, 2025 Offering.

On April 22, 2025, we completed a registered direct offering (the April 22, 2025 Offering and together with the April 4, 2025 Offering, the April 2025 Offerings), in which we issued 6,455 shares of common stock at a purchase price of $310.32 per share. We received $2.0 million in gross proceeds less total issuance costs of $0.2 million. We did not issue any common warrants in connection with the April 22, 2025 Offering.

On June 20, 2025, we completed an offering priced at-the-market (the “June 2025 Offering”) with certain institutional investors, in which we received gross proceeds $8.0 million, which included 136,944 shares of common stock (or pre-funded warrants in lieu thereof, all of which have been exercised as of June 30, 2025) and accompanying common warrants to purchase up to 684,722 shares of common stock at an exercise price of $58.50 per share for a combined purchase price of $58.50 per share and accompanying common warrants. The common warrants became immediately exercisable following the date of stockholder approval on July 24, 2025 and will expire in July 2030. We received $8.0 million in gross proceeds less total issuance costs of $0.7 million. 22,223 shares were exercised in 2025 at an average price of $25.10 per share. As of March 31, 2026, we have 662,508 common warrants outstanding in connection with the June 2025 Offering.

Aptevo uses Black-Scholes valuation model for estimating the fair value of the common warrants included in public and direct offerings. The warrants are classified as an equity instrument because they are both indexed to the Company's own stock and classified in stockholders' equity, are recorded at fair value on the date of issuance. The Company did not issue common warrants in the three months ended March 31, 2026 and 2025.

Additionally, the common warrants issued in our June 2025 Offering include a down-round feature. On January 23, 2026, in connection with the sales of common warrants and common stock, the exercise price of the common warrants issued in connection with the June 2025 Offering was lowered to $11.70 per share representing the floor price of those warrants. Upon the trigger of the down round provision of these common warrants, on January 23, 2026, the Company recorded a deemed dividend of $0.1 million which represents the fair value transferred to the warrant holders from the down round feature being triggered. The deemed dividend increased net loss attributable to common equity by $0.1 million in the condensed consolidated statement of operations for the three months ended March 31, 2026. The Company calculated the difference between the common warrants' fair value on January 23, 2026, the date the down round feature was triggered, using the current exercise price at the time of $19.01 and the new exercise price of $11.70. The fair value of the common warrants prior to and immediately after the exercise price adjustment, were estimated using the Black-Scholes option-pricing model with the following assumptions:


		January 23, 2026

Exercise price		$19.01-$11.70
Expected volatility		178.49%
Risk-free interest rate		3.53%
Expected average life of warrants		4.5

Standby Equity Purchase Agreement

June 2025 SEPA

On June 16, 2025, we entered into a Standby Equity Purchase Agreement with Yorkville. Pursuant to the First SEPA, the Company has the right, but not the obligation, to issue and sell to Yorkville from time to time up to $25.0 million of the Company’s common stock during the 36 months following the execution of the First SEPA, subject to market conditions, restrictions, and satisfaction of the conditions in the First SEPA. As consideration for Yorkville’s irrevocable commitment to purchase the shares of common stock up to the commitment amount (the “First Commitment Amount”), the Company paid a structuring fee in the amount of $25,000 to Yorkville, and the Company has agreed to pay a commitment fee to Yorkville in an amount equal to 2.00% of the First Commitment Amount in five equal installments. We accounted for the structuring and the commitment fee as deferred issuance cost. As of March 31, 2026, the remaining availability under the First SEPA is $8.0 million. On July 24, 2025, we received shareholder approval for the potential issuance of 19.99% or more of the aggregate number of shares of outstanding common stock pursuant to the First SEPA.

January 2026 SEPA

On January 8, 2026, we entered into the Second SEPA, the Company has the right, but not the obligation, to issue and sell to Yorkville from time to time up to $60.0 million (the “Second Commitment Amount”) of our common stock during the 36 months following the execution of the Second SEPA, subject to the restrictions and satisfaction of the conditions in the Second SEPA. The Company paid a structuring fee in the amount of $25,000 to Yorkville, and the Company has agreed to pay a commitment fee to Yorkville in an amount equal to 2.00% of the Second Commitment Amount in five equal installments. Pursuant to the Second SEPA, we will not sell shares of our common stock to Yorkville that would result in the beneficial ownership of Yorkville and its affiliates (on an aggregated basis) exceeding 9.99% of our then outstanding common stock. As of March 31, 2026, the remaining availability under the Second SEPA is $59.4 million. On February 18, 2026, we received shareholder approval for the potential issuance of 19.99% or more of the aggregate number of shares of outstanding common stock pursuant to the Second SEPA.

At The Market Offering Agreement

On April 28, 2025, we entered into an At The Market Offering Agreement (the “ATM Agreement”) with Roth Capital Partners, LLC, as sales agent (“Roth”), for an aggregate offering price of $50.0 million, pursuant to which we may offer and sell shares of our common stock from time to time through Roth. The compensation to Roth for the shares sold pursuant to the ATM Agreement will be an amount equal to 3.0% of the gross sales price of the shares sold under the ATM Agreement. The sale of such shares of common stock by Roth will be effected under the Company’s existing shelf Registration Statement on Form S-3, which was declared effective on February 26, 2025 (the “Registration Statement”). On June 20, 2025, we filed the latest amendment to the prospectus supplement to the Registration Statement pursuant to General Instruction I.B.6 of Form S-3 (“General Instruction I.B.6”), which updated the amount of shares that we are eligible to sell under the ATM Agreement to an aggregate of $8.0 million. We did not issue any shares under the ATM during the three months ended March 31, 2026 and 2025. There is currently no remaining availability under the ATM Agreement due to limitations of General Instruction I.B.6. Additional capacity is expected to become available after October 2026.

Rights Plan

On November 8, 2020, our Board of Directors (the "Board") approved and adopted a Rights Agreement (the "Rights Agreement"), dated as of November 8, 2020, by and between the Company and Broadridge Corporate Issuer Solutions, Inc., as rights agent, pursuant to which the Board declared a dividend of one preferred share purchase right (each, a "Right") for each outstanding

share of the Company’s common stock held by stockholders as of the close of business on November 23, 2020. One Right also will be issued together with each Common Share issued by the Company after November 23, 2020, but before the Distribution Date (as defined below) (or the earlier redemption or expiration of the Rights) and, in certain circumstances, after the Distribution Date. When exercisable, each Right initially would represent the right to purchase from the Company one one-thousandth of a share of a newly-designated series of preferred stock, Series A Junior Participating Preferred Stock, par value $0.001 per share, of the Company. Subject to various exceptions, the Rights become exercisable in the event any person (excluding certain exempted or grandfathered persons) becomes the beneficial owner of ten percent (10%) or more of the Company’s common stock without the approval of the Board. On October 30, 2025, we entered into Amendment No. 5 to the Rights Agreement and extended the expiration of such agreement to October 29, 2026. We have evaluated the rights agreement and determined that it does not represent a derivative or a liability.

2018 Stock Incentive Plan

On July 24, 2025, at the 2025 annual meeting of the stockholders, our stockholders approved the Third Amended and Restated 2018 SIP (the “Third Amended 2018 SIP”) to increase the number of shares authorized for issuance under the 2018 Stock Incentive Plan, as amended and restated by 13,888 shares of common stock (adjusted for 1-for-18 reverse stock split effective as of December 29, 2025). As of March 31, 2026, there are 7,360 shares available to be granted under the Third Amended 2018 SIP.

Stock options and RSUs under the Third Amended 2018 SIP generally vest pro rata over a one-year or three-year period. Stock options terminate ten years from the grant date, though the specific terms of each grant are determined individually. The Company’s executive officers, members of our board of directors, and certain other employees and consultants may be awarded options and/or RSUs with different vesting criteria, and awards granted to non-employee directors will vest over a one-year period. Option exercise and RSU grant prices for new awards granted by the Company equal the closing price of the Company’s common stock on the Nasdaq Capital Market on the date of grant.

Stock-Based Compensation Expense

Stock-based compensation expense includes amortization of stock options and RSUs granted to employees and non-employees and has been reported in our unaudited condensed consolidated statements of operations as $0.1 million and $0.2 million for the three months ended March 31, 2026 and 2025, respectively.

The Company accounts for stock-based compensation by measuring the cost of employee services received in exchange for all equity awards granted based on the fair value of the award as of the grant date. The Company recognizes the compensation expense over the vesting period. All assumptions used to calculate the grant date fair value of non-employee equity awards are generally consistent with the assumptions used for equity awards granted to employees. In the event the Company terminates any of its consulting agreements, the unvested equity underlying the agreements would also be forfeited.

Stock Options

As of March 31, 2026, we had $0 unrecognized compensation expense. The Company did not issue options and had no outstanding options during the three months ended March 31, 2026 and 2025.

Restricted Stock Units

As of March 31, 2026, we have 6,542 shares of RSUs with a weighted average fair value of $40.24 per unit outstanding and expected to vest. There was $0.11 million unrecognized stock-based compensation expense related to unvested RSUs expected to vest over the weighted-average period of 0.4 years.

The fair value of each RSU has been determined to be the closing trading price of the Company’s common stock on the date of grant as quoted on the Nasdaq Capital Market.

Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended
	Jul. 24, 2025	Nov. 08, 2020	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025	Jun. 20, 2025
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock price per share						$ 58.5
Costs from issuance of common stock			$ 872	$ 0
Preferred stock, par value			$ 0.001		$ 0.001
Stock-based compensation expense			$ 100	$ 200
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Units, Outstanding and expected to vest			6,542
Weighted average fair value			$ 40.24
Unrecognized compensation expense			$ 110
Options expected to vest, weighted average period			4 months 24 days
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense			$ 0
Number of shares issued under share-based payment arrangement			0	0
Number of shares outstanding under share-based payment arrangement			0	0
2018 Stock Incentive Plan \| Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock authorized for issuance under Stock Plan	13,888
Number of shares available for grant			7,360
Stock plan termination period	10 years
2018 Stock Incentive Plan \| Restricted Stock Units \| Non-employee Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock plan vesting period	1 year
Broadridge Corporate Issuer Solutions
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Preferred share purchase right		1
Broadridge Corporate Issuer Solutions \| Series A Junior Participating Preferred Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Preferred stock, par value		$ 0.001
Share portion entitled to purchase by rights		When exercisable, each Right initially would represent the right to purchase from the Company one one-thousandth of a share of a newly-designated series of preferred stock,
Percentage of beneficial ownership		10.00%
Minimum \| 2018 Stock Incentive Plan \| Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock plan vesting period	1 year
Maximum \| 2018 Stock Incentive Plan \| Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock plan vesting period	3 years
Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock net of issuance cost,shares			205,923
Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants exercise price, per share						$ 58.5

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Mar. 31, 2026
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Rule 10b5-1 Arrangement Modified	false
Non-Rule 10b5-1 Arrangement Modified	false

Equity - 2023 and 2024 Common Warrants - Additional Information (Details) - $ / shares	Mar. 31, 2026	Jun. 20, 2025	Apr. 04, 2025	Dec. 12, 2024
Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants exercise price, per share		$ 58.5
Number of common stock to be issued up conversion of warrants		684,722
Registered Direct Offering
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants exercise price, per share			$ 428.4
Registered Direct Offering \| Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of common stock to be issued up conversion of warrants			9,803
Warrants expiration date			May 14, 2025
Existing Warrants \| Registered Direct Offering
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants exercise price, per share				$ 3,430.8
2023 Common Warrants \| Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Outstanding warrants issued	3
August 2023 Warrant \| Minimum \| Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants exercise price, per share	$ 136,555.2
August 2023 Warrant \| Maximum \| Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants exercise price, per share	$ 363,369.3
April 2024 Warrant \| Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Outstanding warrants issued	4,645
April 2024 Warrant \| Minimum \| Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants exercise price, per share	$ 428.4
April 2024 Warrant \| Maximum \| Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants exercise price, per share	$ 17,892

Cash and Cash Equivalents - Additional Information (Details)	3 Months Ended
	Mar. 31, 2026
Restricted Cash And Cash Equivalents Items [Line Items]
Cash equivalents, maturity period	90 days

Segment Information (Tables)

3 Months Ended

Mar. 31, 2026

Summary of Significant Expense Categories

The table below summarizes the significant expense categories regularly reviewed by the CODM for the three months ended March 31, 2026 and 2025.


	For the Three Months Ended March 31,
	2026			2025
Operating expenses
Research and development	$	(3,924	)	$	(3,633	)
General and administrative		(2,913	)		(2,847	)
Other segment items (a)		140			72
Net loss (b)	$	(6,697	)	$	(6,408	)

(a) Other segment items included in segment loss includes interest income, interest expense, rental income and foreign exchange gain/loss.

(b) The Company is a single operating segment and therefore the measure of segment net loss is the same as consolidated net loss and does not require reconciliation.

Summary of Significant Asset Categories

The table below summarizes the significant asset categories regularly reviewed by the CODM as of March 31, 2026 and 2025.


	As of March 31,
	2026		2025
Assets
Cash and cash equivalents	$	14,525	$	2,139

Equity - 2024 Common Warrants - Additional Information (Details) - $ / shares	Mar. 31, 2026	Jun. 20, 2025	Apr. 04, 2025	Dec. 12, 2024
Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants exercise price, per share		$ 58.5
2023 Common Warrants \| Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants outstanding	3
April 2024 Warrant \| Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants outstanding	4,645
Registered Direct Offering
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants exercise price, per share			$ 428.4
Registered Direct Offering \| Existing Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants exercise price, per share				$ 3,430.8

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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+ Details

Segment Information - Summary of Significant Expense Categories (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Operating Expenses [Abstract]
Research and development	$ (3,924)	$ (3,633)
General and administrative	(2,913)	(2,847)
Other segment items	140	72
Net loss	$ (6,697)	$ (6,408)

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+ Details

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit
Balance at Dec. 31, 2024	$ 4,755	$ 84	$ 252,248	$ (247,577)
Balance (in shares) at Dec. 31, 2024		4,051
Stock-based compensation	180		180
Net loss	(6,408)			(6,408)
Balance at Mar. 31, 2025	(1,473)	$ 84	252,428	(253,985)
Balance (in shares) at Mar. 31, 2025		4,051
Balance at Dec. 31, 2025	17,381	$ 114	292,382	(275,115)
Balance (in shares) at Dec. 31, 2025		997,830
Issuance of common stock net of issuance cost	872		872
Issuance of common stock net of issuance cost,shares		205,923
Stock-based compensation	57		57
Payment in lieu of fractional shares	(1)		(1)
Dividend attributable to down round feature of warrants			97	(97)
Payment in lieu of fractional shares in connection with the 1-for-44 reverse stock split effected on March 5, 2024	(1)		(1)
Net loss	(6,697)			(6,697)
Balance at Mar. 31, 2026	$ 11,612	$ 114	$ 293,407	$ (281,909)
Balance (in shares) at Mar. 31, 2026		1,203,753

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Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering.

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+ Details

Net Loss per Share - Summary of Potentially Dilutive Shares Excluded from Calculation of Net Loss Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Common Warrants
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	676,968	4,642
Unvested RSUs
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	6,542	4

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Mar. 31, 2026	Mar. 31, 2025
Pay vs Performance Disclosure
Net Income (Loss)	$ (6,697)	$ (6,408)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

Equity - At The Market Offering Agreement - Additional Information (Details) - At The Market Offering - USD ($)	Jun. 20, 2025	Apr. 28, 2025	Mar. 31, 2026	Mar. 31, 2025
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock offering aggregate price	$ 8,000,000	$ 50,000,000
Percentage of gross sales price shares sold		3.00%
Shares issued			0	0
Remaining availability			$ 0

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Leases [Abstract]
Operating lease cost	$ 297	$ 297
Total lease cost	$ 297	$ 297

Cash and Cash Equivalents (Tables)

3 Months Ended

Mar. 31, 2026

Cash and Cash Equivalents [Abstract]

Schedule of Cash and Cash Equivalents

The following table shows our cash and cash equivalents as of March 31, 2026 and December 31, 2025:


	March 31,		December 31,
(in thousands)	2026		2025
Cash	$	856	$	1,123
Cash equivalents		13,668		20,496
Total cash and cash equivalents	$	14,525	$	21,619

Cash and Cash Equivalents - Schedule of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025	Mar. 31, 2025
Cash and Cash Equivalents [Abstract]
Cash	$ 856	$ 1,123
Cash equivalents	13,668	20,496
Total cash and cash equivalents	$ 14,525	$ 21,619	$ 2,139

- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
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+ Details

Segment Information - Summary of Significant Asset Categories (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025	Mar. 31, 2025
Assets [Abstract]
Cash and cash equivalents	$ 14,525	$ 21,619	$ 2,139

Cash and Cash Equivalents

3 Months Ended

Mar. 31, 2026

Cash and Cash Equivalents [Abstract]

Cash and Cash Equivalents

Note 4. Cash and Cash Equivalents

The Company’s cash equivalents are highly liquid investments with a maturity of 90 days or less at the date of purchase and include time deposits and investments in money market funds.

The following table shows our cash and cash equivalents as of March 31, 2026 and December 31, 2025:


	March 31,		December 31,
(in thousands)	2026		2025
Cash	$	856	$	1,123
Cash equivalents		13,668		20,496
Total cash and cash equivalents	$	14,525	$	21,619

Prepaid Expenses, Other Current Assets, Accrued Expenses, and Other Current Liabilities - Summary of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Prepaid Expenses, Other Current Assets, Accrued Expenses, and Other Current Liabilities [Abstract]
Prepaid clinical expenses	$ 608	$ 609
Other current assets	851	853
Total prepaid expenses and other current assets	$ 1,459	$ 1,462

Leases - Summary of Right of Use Assets Acquired Under Operating Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Lessee Lease Description [Line Items]
Operating lease right-of-use asset	$ 3,650		$ 3,810
For operating leases	344	$ 344
Seattle Office Lease, Including Amendment
Lessee Lease Description [Line Items]
Operating lease right-of-use asset	$ 3,650		$ 3,810

Fair Value Measurements - Additional Information (Details) - USD ($)	Mar. 31, 2026	Dec. 31, 2025
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Money market funds	$ 13,700,000	$ 20,500,000
Level Two
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value assets	0	0
Level Three
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value assets	$ 0	$ 0

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Operating expenses:
Research and development	$ (3,924)	$ (3,633)
General and administrative	(2,913)	(2,847)
Loss from operations	(6,837)	(6,480)
Other income:
Other income, net	140	72
Net loss	(6,697)	(6,408)
Dividend attributable to down round feature of warrants	(97)	0
Net loss attributable to common stockholders	$ (6,794)	$ (6,408)
Basic and diluted net loss per share:
Basic net loss per share	$ (6.41)	$ (1,581.81)
Diluted net loss per share	$ (6.41)	$ (1,581.81)
Shares used in calculation:
Basic shares used in calculation	1,060,678	4,051
Diluted shares used in calculation	1,060,678	4,051

Equity - Standby Equity Purchase Agreement - Additional Information (Details) - USD ($)	Feb. 18, 2026	Jan. 08, 2026	Jul. 24, 2025	Jun. 16, 2025	Mar. 31, 2026	Dec. 31, 2025
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock value					$ 114,000	$ 114,000
First Standby Equity Purchase Agreement
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock value				$ 25,000,000
Structuring fee				$ 25,000
Percentage of commitment fee				2.00%
Remaining availability under SEPA					8,000,000
Percentage of outstanding shares approved for potential issuance			19.99%
Second Standby Equity Purchase Agreement
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock value		$ 60,000,000
Structuring fee		$ 25,000
Percentage of commitment fee		2.00%
Remaining availability under SEPA					$ 59,400,000
Beneficial ownership exceeding percentage of outstanding common stock		9.99%
Percentage of outstanding shares approved for potential issuance	19.99%

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Collaboration Agreements - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Research and development expense	$ 40	$ 100
Percentage of cost related to research and development	50.00%	50.00%

Equity - 2025 Equity Offerings and Common Warrants - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands						3 Months Ended		12 Months Ended
	Jan. 23, 2026	Jun. 20, 2025	Apr. 22, 2025	Apr. 04, 2025	Dec. 12, 2024	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Costs from issuance of common stock						$ 872	$ 0
Common stock price per share		$ 58.5
Increase in net loss attributable to common equity due to deemed dividend						$ 97	$ 0
Warrant issued during period						0	0
Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of common stock to be issued up conversion of warrants		684,722
Warrants exercise price, per share		$ 58.5
2025 Common Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants exercise price, per share	$ 11.7
Deemed dividend	$ 100
Increase in net loss attributable to common equity due to deemed dividend						$ 100
2025 Common Warrants \| Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants exercise price, per share	$ 19.01
2025 Common Warrants \| Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants exercise price, per share	$ 11.7
At-The-Market Offering
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Costs from issuance of common stock		$ 8,000
Issuance of common stock shares		136,944
At-The-Market Offering \| Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants expiration date		Jul. 31, 2030
Warrants exercise price, per share								$ 25.1
Warrants outstanding						662,508
Gross proceeds		$ 8,000
Total issuance costs		$ 700
Common warrants exercised								22,223
Registered Direct Offering
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Issuance of common stock shares				4,901
Warrants exercise price, per share				$ 428.4
Warrant modification - incremental fair value				$ 600
Registered Direct Offering \| Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock price per share				$ 428.4
Number of common stock to be issued up conversion of warrants				9,803
Warrants expiration date				May 14, 2025
Gross proceeds				$ 2,100
Total issuance costs				$ 200
Registered Direct Offering \| Existing Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Issuance of common stock shares					4,575
Warrants exercise price, per share					$ 3,430.8
Registered Direct Offering \| 2025 Common Warrants \| Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants outstanding						9,812
April 4, 2025 Registered Direct Offering
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Issuance of common stock shares			6,455
Common stock price per share			$ 310.32
Gross proceeds			$ 2,000
Total issuance costs			$ 200

Net Loss per Share (Tables)

3 Months Ended

Mar. 31, 2026

Earnings Per Share [Abstract]

Computation of Basic and Diluted Net Loss per Share

The following table presents the computation of basic and diluted net loss per share (in thousands, except share and per share amounts):


	For the Three Months Ended March 31,
	2026			2025
Net loss	$	(6,697	)	$	(6,408	)
Dividend attributable to down round feature of warrants		(97	)		—
Net loss attributable to common stockholders	$	(6,794	)	$	(6,408	)

Basic and diluted net loss per share:	$	(6.41	)	$	(1,581.81	)

Shares used in calculation:		1,060,678			4,051

Summary of Potentially Dilutive Shares Excluded from Calculation of Net Loss Per Share

The following table represents all potentially dilutive shares:


	As of March 31,
	2026		2025
Common warrants		676,968		4,642
Unvested RSUs		6,542		4

Subsequent Events - Additional Information (Details) - Standby Equity Purchase Agreement - Subsequent Events $ / shares in Units, shares in Thousands, $ in Millions	1 Months Ended
	May 13, 2026 USD ($) $ / shares shares
Subsequent Event [Line Items]
Number of shares sold \| shares	40
Average price \| $ / shares	$ 4.86
Net proceeds \| $	$ 0.2

Nature of Business and Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2026
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP"). These unaudited condensed consolidated financial statements include all adjustments, which include normal recurring adjustments, necessary for the fair presentation of the Company’s financial position. These unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2025, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates and changes in these estimates are recorded when known. The unaudited condensed consolidated financial statements include the accounts of the Company and our wholly owned subsidiary, Aptevo Research and Development LLC ("Aptevo R&D"). All intercompany balances and transactions have been eliminated. For all periods presented in the financial statements and accompanying footnotes, share and per share amounts have been retroactively adjusted to reflect the reverse stock splits (as discussed below).
Reclassification	Reclassification Certain amounts in the accompanying consolidated financial statements were reclassified to conform to the current period presentation. There has been no impact on previously reported net loss or stockholders' equity from such reclassification.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires estimates and assumptions that affect the reported amounts of assets and liabilities, revenues and expenses, and related disclosures of contingent liabilities in the unaudited condensed financial statements and accompanying notes. Estimates are used for, but not limited to, clinical accruals, useful lives of equipment, commitments and contingencies, stock-based compensation, fair value of common warrants, and incremental borrowing rate (IBR) used for our lease. Given the global economic and geopolitical climate, these estimates are becoming more challenging, and actual results could differ materially from those estimates.
Significant Accounting Policies	Significant Accounting Policies Our significant accounting policies were reported in our Annual Report on Form 10-K for the year ended December 31, 2025 that was filed with the Securities and Exchange Commission (the "SEC") on March 26, 2026. Our other significant accounting policies have not changed materially from the policies previously reported.
Accounting Pronouncements Pending Adoption	Accounting Pronouncements Pending Adoption In November 2024, the Financial Accounting Standards Board issued ASU 2024-03, Disaggregation of Income Statement Expenses (DISE). The purpose of ASU 2024-03 is to enhance expense disclosures by requiring additional disaggregated information about specified categories of expenses included in certain expense captions presented on the face of the income statement. This ASU is effective for fiscal years beginning after December 15, 2026, and for interim periods within fiscal years beginning after December 15, 2027. The amendments may be applied either prospectively to financial statements issued for reporting periods after the effective date of this ASU or retrospectively to all prior periods presented in the financial statements. The Company is currently assessing the impact this ASU will have on its financial statements.

- Definition

Disclosure of accounting policy for the use of estimates in the preparation of financial statements in conformity with generally accepted accounting principles.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 235
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
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-URI https://asc.fasb.org/1943274/2147482861/275-10-50-1

+ Details

Prepaid Expenses, Other Current Assets, Accrued Expenses, and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Prepaid Expenses, Other Current Assets, Accrued Expenses, and Other Current Liabilities [Abstract]
Accrued clinical, research and development costs	$ 1,458	$ 1,154
Accrued compensation and benefits	803	2,421
Accrued professional service costs	303	480
Other accruals	413	252
Total accrued expenses and other current liabilities	$ 2,977	$ 4,307

Fair Value Measurements

3 Months Ended

Mar. 31, 2026

Fair Value Disclosures [Abstract]

Fair Value Measurements

Note 3. Fair Value Measurements

The Company’s estimates of fair value for financial assets and financial liabilities are based on the framework established in the fair value accounting guidance. The framework is based on the inputs used in valuation, it gives the highest priority to quoted prices in active markets and requires that observable inputs be used in the valuations when available. The disclosure of fair value estimates in the fair value accounting guidance hierarchy is based on whether the significant inputs into the valuation are observable. In determining the level of the hierarchy in which the estimate is disclosed, the highest priority is given to unadjusted quoted prices in active markets and the lowest priority to unobservable inputs that reflect the Company’s significant market assumptions. The level in the fair value hierarchy within which the fair value measurement is reported is based on the lowest level input that is significant to the measurement in its entirety. The three levels of the hierarchy are as follows:

Level 1— Quoted prices in active markets for identical assets and liabilities;

Level 2— Inputs other than quoted prices in active markets that are either directly or indirectly observable; and

Level 3— Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

At March 31, 2026 and December 31, 2025, we had $13.7 million and $20.5 million in Level 1 money market funds, respectively. The carrying amounts of our money market funds approximate their fair value. At March 31, 2026 and December 31, 2025, we did not have any Level 2 or Level 3 assets.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Subsequent Events

3 Months Ended

Mar. 31, 2026

Subsequent Events [Abstract]

Subsequent Events

Note 10. Subsequent Events

We sold 0.04 million shares of our common stock under SEPAs at an average price of $4.86 per share and raised $0.2 million in net proceeds during the subsequent events period.

Equity - Summary of Fair Value of Common Warrants Prior to and Immediately After Exercise Price Adjustment, were Estimated Using Black-Scholes Option-Pricing Model Assumptions (Details)	Jan. 23, 2026 yr
Exercise Price \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants measurement input	19.01
Exercise Price \| Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants measurement input	11.7
Expected Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants measurement input	178.49
Risk-free Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants measurement input	3.53
Expected Average Life of Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants measurement input	4.5

Leases (Tables)

3 Months Ended

Mar. 31, 2026

Leases [Abstract]

Components of Lease Expense

Components of lease expense:


	For the Three Months Ended March 31,
(in thousands)	2026		2025
Operating lease cost	$	297	$	297
Total lease cost	$	297	$	297

Summary of Right of Use Assets Acquired Under Operating Leases

Right of use assets acquired under operating leases:


	As of March 31,		As of December 31,
(in thousands)	2026		2025
Seattle office lease, including amendment	$	3,650	$	3,810
Total operating leases	$	3,650	$	3,810

Lease payments:


	For the Three Months Ended March 31,
(in thousands)	2026		2025
For operating leases	$	344	$	344

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Current assets:
Cash and cash equivalents	$ 14,525	$ 21,619
Prepaid expenses and other current assets	1,459	1,462
Total current assets	15,984	23,081
Property and equipment, net	268	303
Operating lease right-of-use asset	3,650	3,810
Total assets	19,902	27,194
Current liabilities:
Accounts payable	890	877
Accrued expenses and other current liabilities	2,977	4,307
Operating lease liability, current portion	892	866
Total current liabilities	4,760	6,050
Operating lease liability, current portion	3,530	3,763
Total liabilities	8,290	9,813
Stockholders' equity:
Preferred stock: $0.001 par value; 15,000,000 shares authorized, zero shares issued or outstanding
Common stock: $0.001 par value; 500,000,000 shares authorized; 1,203,753 and 997,830 shares issued and outstanding at March 31, 2026 and December 31, 2025, respectively	114	114
Additional paid-in capital	293,407	292,382
Accumulated deficit	(281,909)	(275,115)
Total stockholders' equity	11,612	17,381
Total liabilities and stockholders' equity	$ 19,902	$ 27,194

Net Loss per Share

3 Months Ended

Mar. 31, 2026

Earnings Per Share [Abstract]

Net Loss per Share

Note 7. Net Loss per Share

Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common share equivalents outstanding for the period using the as-if converted method. For the purpose of this calculation, warrants, stock options and restricted stock units ("RSUs") are only included in the calculation of diluted net loss per share when their effect is dilutive.

We utilize the control number concept in the computation of diluted earnings per share to determine whether potential common stock instruments are dilutive. The control number used is net loss for the period. The control number concept requires that the same number of potentially dilutive securities applied in computing diluted earnings per share be applied to all other categories of income or loss, regardless of their anti-dilutive effect on such categories.

Common stock equivalents include warrants, stock options and unvested RSUs.

The following table presents the computation of basic and diluted net loss per share (in thousands, except share and per share amounts):


	For the Three Months Ended March 31,
	2026			2025
Net loss	$	(6,697	)	$	(6,408	)
Dividend attributable to down round feature of warrants		(97	)		—
Net loss attributable to common stockholders	$	(6,794	)	$	(6,408	)

Basic and diluted net loss per share:	$	(6.41	)	$	(1,581.81	)

Shares used in calculation:		1,060,678			4,051

The following table represents all potentially dilutive shares:


	As of March 31,
	2026		2025
Common warrants		676,968		4,642
Unvested RSUs		6,542		4

We use the treasury stock method when determining dilutive shares. For the three months ended March 31, 2026 and 2025, the Company was in a net loss position, therefore the share number used to calculate diluted earnings per share is the same as the basic earnings per share.

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Operating Activities
Net loss	$ (6,697)	$ (6,408)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	57	180
Non-cash lease expense	271	273
Depreciation and amortization	35	61
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	3	477
Accounts payable	13	278
Accrued expenses and other current liabilities	(1,303)	(1,092)
Operating lease liability	(344)	(344)
Net cash used in operating activities	(7,965)	(6,575)
Investing Activities
Net cash from investing activities	0	0
Financing Activities
Proceeds from issuance of common stock, net of issuance costs	872	0
Payments in lieu of fractional shares	(1)	0
Net cash provided by financing activities	871	0
Increase (decrease) in cash and cash equivalents	(7,094)	(6,575)
Cash and cash equivalents at beginning of period	21,619	8,714
Cash and cash equivalents at end of period	14,525	2,139
Supplemental Cash Flow Information
Dividend attributable to down round feature of warrants	$ 97	$ 0

Prepaid Expenses, Other Current Assets, Accrued Expenses, and Other Current Liabilities (Tables)

3 Months Ended

Mar. 31, 2026

Prepaid Expenses, Other Current Assets, Accrued Expenses, and Other Current Liabilities [Abstract]

Summary of Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consisted of the following as of March 31, 2026 and December 31, 2025.


	March 31,		December 31,
(in thousands)	2026		2025
Prepaid clinical expenses	$	608	$	609
Other current assets		851		853
Total prepaid expenses and other current assets	$	1,459	$	1,462

Summary of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following as of March 31, 2026 and December 31, 2025.


	March 31,		December 31,
(in thousands)	2026		2025
Accrued clinical, research and development costs	$	1,458	$	1,154
Accrued compensation and benefits		803		2,421
Accrued professional service costs		303		480
Other accruals		413		252
Total accrued expenses and other current liabilities	$	2,977	$	4,307

Net Loss per Share - Computation of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Earnings Per Share [Abstract]
Net loss	$ (6,697)	$ (6,408)
Dividend attributable to down round feature of warrants	97	0
Net loss attributable to common stockholders	$ (6,794)	$ (6,408)
Basic and diluted net loss per share:
Basic net loss per share	$ (6.41)	$ (1,581.81)
Diluted net loss per share	$ (6.41)	$ (1,581.81)
Shares used in calculation:
Basic shares used in calculation	1,060,678	4,051
Diluted shares used in calculation	1,060,678	4,051

Equity - Summary of Stock-based Compensation Expense Includes Amortization of Stock Options and Restricted Stock Units Granted (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 0.1	$ 0.2

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' DEFICIT EQUITY (Unaudited) (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2026 USD ($)
Gross proceeds	$ 872
Common Stock
Gross proceeds	1,300
Issuance costs	$ 400

Nature of Business and Significant Accounting Policies

3 Months Ended

Mar. 31, 2026

Accounting Policies [Abstract]

Nature of Business and Significant Accounting Policies

Note 1. Nature of Business and Significant Accounting Policies

Organization and Liquidity

Aptevo Therapeutics Inc. (Aptevo, we, us, or the Company) is a clinical-stage, research and development biotechnology company focused on developing novel immunotherapy candidates for the treatment of different forms of cancer. We have developed two versatile and enabling platform technologies for rational design of precision immune modulatory drugs and have two clinical candidates and six preclinical candidates currently in development. Clinical candidate mipletamig is a CD123xCD3 T cell engager that is currently being evaluated in the RAINIER study, a Phase 1b/2 program evaluating mipletamig in combination with standard of care venetoclax + azacitidine for the treatment of frontline acute myelogenous leukemia (AML) patients who are unfit for intensive chemotherapy. The ongoing Phase 1b trial was initiated in August 2024. Clinical candidate ALG.APV-527 targets 4-1BB (co-stimulatory receptor) and 5T4 (tumor antigen). The compound is designed to reactivate antigen-primed T cells to specifically kill tumor cells and was most recently evaluated in a Phase 1 clinical trial for the treatment of multiple solid tumor types likely to express 5T4. The Company is also focused on advancing select molecules from its preclinical pipeline with the goal of advancing them toward IND-ready status.

We are currently trading on the Nasdaq Capital Market under the symbol "APVO."

The accompanying financial statements have been prepared on a basis that assumes we will continue as a going concern, which contemplates the realization of assets and satisfaction of liabilities and commitments in the normal course of business. The consolidated financial statements do not include any adjustments that might result from the outcome of the uncertainty of our ability to continue as a going concern, nor do they include adjustments to reflect the possible future effects of the recoverability and classification of recorded asset amounts and classifications of liabilities that might be necessary should the Company be unable to continue as a going concern. For the three months ended March 31, 2026, we had a net loss of $6.7 million. We had an accumulated deficit of $281.9 million as of March 31, 2026. For the three months ended March 31, 2026, net cash used in our operating activities was $8.0 million. We have suffered recurring losses from operations and negative cash flows from operating activities. In the first quarter of 2026, we raised approximately $0.9 million in aggregate net proceeds through the issuance of common stock under the Standby Equity Purchase Agreement with YA II PN, LTD., a Cayman Islands exempt limited company (“Yorkville”), dated June 16, 2025 (the “First SEPA”) and the Standby Equity Purchase Agreement with Yorkville, dated January 8, 2026 (the “Second SEPA” and collectively with the First SEPA, the “SEPAs”). In addition, we raised $0.2 million during the subsequent events period under the SEPAs. When considered in aggregate, these factors raise substantial doubt about our ability to continue as a going concern for the one-year period from the date of issuance of these financial statements. We will need to raise additional funds to support our operating and capital needs in addition to our existing cash resources, cash to be generated from future milestones related to IXINITY sales and regulatory approvals achieved by Medexus Pharmaceuticals ("Medexus"), sales of common stock under the SEPAs, and exercise of common warrants. We may choose to raise additional funds to support our operating and capital needs in the future.

We continue to face significant challenges and uncertainties and, as a result, our available capital resources may be consumed more rapidly than currently expected due to: (a) changes we may make to the business that affect ongoing operating expenses; (b) changes we may make in our business strategy; (c) changes we may make in our research and development spending plans; (d) whether and to what extent potential milestones are received from Medexus with respect to IXINITY; (e) macroeconomic conditions such as rising inflation, potential trade war, and other costs as well as political events such as a U.S. federal government shutdown, evolving healthcare policies, ongoing conflicts in Europe and the Middle East and military actions; and (f) other items affecting our forecasted level of expenditures and use of cash resources. We may attempt to obtain other public or private financing, collaborative or licensing arrangements with strategic partners, or through credit lines or other debt financing sources to increase the funds available to fund operations. However, we may not be able to secure such funding in a timely manner or on favorable terms, if at all. Furthermore, if we issue equity or debt securities to raise additional funds, our existing stockholders may experience dilution, and the new equity or debt securities may have rights, preferences, and privileges senior to those of our existing stockholders. If we raise additional funds through collaboration, licensing, or other similar arrangements, it may be necessary to relinquish valuable rights to our potential products or proprietary technologies, or grant licenses on terms that are not favorable to us. Without additional funds, we may be forced to delay, scale back, or eliminate some of our research and development activities or other operations and potentially delay product development in an effort to provide sufficient funds to continue our operations. If any of these events occur, our ability to achieve our development goals may be adversely affected. Given the continuing global economic and geopolitical climate, including stock market volatility and potential trade war, we may experience delays or difficulties in the financing environment and raising capital due to economic uncertainty.

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP"). These unaudited condensed consolidated financial statements include all adjustments, which include normal recurring adjustments, necessary for the fair presentation of the Company’s financial position. These unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2025, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025.

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates and changes in these estimates are recorded when known.

The unaudited condensed consolidated financial statements include the accounts of the Company and our wholly owned subsidiary, Aptevo Research and Development LLC ("Aptevo R&D"). All intercompany balances and transactions have been eliminated. For all periods presented in the financial statements and accompanying footnotes, share and per share amounts have been retroactively adjusted to reflect the reverse stock splits (as discussed below).

Reclassification

Certain amounts in the accompanying consolidated financial statements were reclassified to conform to the current period presentation. There has been no impact on previously reported net loss or stockholders' equity from such reclassification.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires estimates and assumptions that affect the reported amounts of assets and liabilities, revenues and expenses, and related disclosures of contingent liabilities in the unaudited condensed financial statements and accompanying notes. Estimates are used for, but not limited to, clinical accruals, useful lives of equipment, commitments and contingencies, stock-based compensation, fair value of common warrants, and incremental borrowing rate (IBR) used for our lease. Given the global economic and geopolitical climate, these estimates are becoming more challenging, and actual results could differ materially from those estimates.

Significant Accounting Policies

Our significant accounting policies were reported in our Annual Report on Form 10-K for the year ended December 31, 2025 that was filed with the Securities and Exchange Commission (the "SEC") on March 26, 2026. Our other significant accounting policies have not changed materially from the policies previously reported.

Accounting Pronouncements Pending Adoption

In November 2024, the Financial Accounting Standards Board issued ASU 2024-03, Disaggregation of Income Statement Expenses (DISE). The purpose of ASU 2024-03 is to enhance expense disclosures by requiring additional disaggregated information about specified categories of expenses included in certain expense captions presented on the face of the income statement. This ASU is effective for fiscal years beginning after December 15, 2026, and for interim periods within fiscal years beginning after December 15, 2027. The amendments may be applied either prospectively to financial statements issued for reporting periods after the effective date of this ASU or retrospectively to all prior periods presented in the financial statements. The Company is currently assessing the impact this ASU will have on its financial statements.

Leases

3 Months Ended

Mar. 31, 2026

Leases [Abstract]

Leases

Note 5. Leases

Office Space Lease - Operating

We have an operating lease related to our office and laboratory space in Seattle, Washington with a term through April 2030 and two options to extend the lease term, each by five years. As of March 31, 2026, we are not reasonably certain to exercise the two options to extend the lease term and our lease liability is recorded through April 30, 2030.

For the three months ended March 31, 2026 and 2025, we recorded $0.2 million related to variable lease expense.

Components of lease expense:


	For the Three Months Ended March 31,
(in thousands)	2026		2025
Operating lease cost	$	297	$	297
Total lease cost	$	297	$	297

Right of use assets acquired under operating leases:


	As of March 31,		As of December 31,
(in thousands)	2026		2025
Seattle office lease, including amendment	$	3,650	$	3,810
Total operating leases	$	3,650	$	3,810

Lease payments:


	For the Three Months Ended March 31,
(in thousands)	2026		2025
For operating leases	$	344	$	344

As of March 31, 2026, the long-term and current portion of the lease liabilities was $3.5 million and $0.9 million, respectively. As of March 31, 2025, the long-term and current portion of the lease liabilities was $4.4 million and $0.8 million, respectively.

As of March 31, 2026, the weighted-average remaining lease term and weighted-average discount rate for operating leases was 4.08 years and 12.03%.

Nature of Business and Significant Accounting Policies - Additional Information (Details) $ in Thousands	1 Months Ended	3 Months Ended
	May 13, 2026 USD ($)	Mar. 31, 2026 USD ($) Platform	Mar. 31, 2025 USD ($)	Dec. 31, 2025 USD ($)
Nature Of Business [Line Items]
Number of technology platforms \| Platform		2
Net loss		$ (6,697)	$ (6,408)
Accumulated deficit		(281,909)		$ (275,115)
Net cash used in operating activities		(7,965)	$ (6,575)
First and Second SEPA
Nature Of Business [Line Items]
Net proceeds		900
First and Second SEPA \| Subsequent Events
Nature Of Business [Line Items]
Net proceeds	$ 200
Nasdaq Capital Market
Nature Of Business [Line Items]
Net loss		(6,700)
Accumulated deficit		(281,900)
Net cash used in operating activities		$ 8,000

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

- Definition

Amount of accumulated undistributed earnings (deficit).

+ References + Details

Segment Information

3 Months Ended

Mar. 31, 2026

Segment Reporting [Abstract]

Segment Information

Note 9. Segment Information

Operating segments are identified as components of an entity about which separate discrete financial information is available for evaluation by the chief operating decision maker ("CODM"), or decision-making group, in making decisions on how to allocate resources and assess performance. The Company's CODM, the Chief Executive Officer, views the Company's operations as one operating segment, which is discovery and development of novel oncology therapeutics. The discovery and development of novel oncology therapeutics segment develops novel immunotherapy candidates for the treatment of different forms of cancer. Our clinical and preclinical candidates were developed using two versatile and enabling platform technologies, ADAPTIR™Ò and ADAPTIR-FLEX™Ò. The Company does not have revenue in the current comparative period, incurs expenses primarily in North America and manages the business activities on a consolidated basis.

The accounting policies of the novel oncology therapeutics segment are the same as those described in the summary of significant accounting policies.

The CODM assesses performance for the novel oncology therapeutics segment and decides how to allocate resources based on net loss that also is reported on the income statement as consolidated net loss. The measure of segment assets is reported on the balance sheet as cash and cash equivalents.

The Company has not generated any product revenue in the current period and expects to continue to incur significant expenses and operating losses for the foreseeable future as we advance our product candidates through all stages of development and clinical trials.

As such, the CODM uses cash forecast models in deciding how to invest into the novel oncology therapeutics segment. Such cash forecast models are reviewed to assess the entity-wide operating results and performance. Net loss is used to monitor budget versus actual results. Monitoring budgeted versus actual results, net cash used in operating activities for the period and cash on hand are used in assessing performance of the segment.

The table below summarizes the significant expense categories regularly reviewed by the CODM for the three months ended March 31, 2026 and 2025.


	For the Three Months Ended March 31,
	2026			2025
Operating expenses
Research and development	$	(3,924	)	$	(3,633	)
General and administrative		(2,913	)		(2,847	)
Other segment items (a)		140			72
Net loss (b)	$	(6,697	)	$	(6,408	)

(a) Other segment items included in segment loss includes interest income, interest expense, rental income and foreign exchange gain/loss.

(b) The Company is a single operating segment and therefore the measure of segment net loss is the same as consolidated net loss and does not require reconciliation.

For the three months ended March 31, 2026 and 2025, the net cash used in operating activities was $8.0 million and $6.6 million, respectively. The table below summarizes the significant asset categories regularly reviewed by the CODM as of March 31, 2026 and 2025.


	As of March 31,
	2026		2025
Assets
Cash and cash equivalents	$	14,525	$	2,139

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

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+ Details

Leases - Additional Information (Details) $ in Thousands	3 Months Ended
Leases - Additional Information (Details) $ in Thousands	Mar. 31, 2026 USD ($) RenewalOption	Mar. 31, 2025 USD ($)	Dec. 31, 2025 USD ($)
Lessee Lease Description [Line Items]
Operating lease right-of-use asset	$ 3,650		$ 3,810
Long term portion of operating lease liabilities	3,530	$ 4,400	3,763
Current portion of operating lease liabilities	$ 892	$ 800	$ 866
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long term portion of operating lease liabilities	Long term portion of operating lease liabilities
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Current portion of operating lease liabilities	Current portion of operating lease liabilities
Weighted average remaining lease term for operating leases	4 years 29 days
Weighted discount rate for operating leases	12.03%
Office Space Lease
Lessee Lease Description [Line Items]
Initial operating lease term date	2030-04
Operating lease renewal option description	term through April 2030 and two options to extend the lease term, each by five years
Operating lease renewal option term	5 years
Number of operating lease renewal option \| RenewalOption	2
Operating lease option to extend	true
Variable expense	$ 200	$ 200

Prepaid Expenses, Other Current Assets, Accrued Expenses, and Other Current Liabilities

3 Months Ended

Mar. 31, 2026

Prepaid Expenses, Other Current Assets, Accrued Expenses, and Other Current Liabilities [Abstract]

Prepaid Expenses, Other Current Assets, Accrued Expenses, and Other Current Liabilities

Note 6. Prepaid Expenses, Other Current Assets, Accrued Expenses, and Other Current Liabilities.

Prepaid expenses and other current assets consisted of the following as of March 31, 2026 and December 31, 2025.


	March 31,		December 31,
(in thousands)	2026		2025
Prepaid clinical expenses	$	608	$	609
Other current assets		851		853
Total prepaid expenses and other current assets	$	1,459	$	1,462

Accrued expenses and other current liabilities consisted of the following as of March 31, 2026 and December 31, 2025.


	March 31,		December 31,
(in thousands)	2026		2025
Accrued clinical, research and development costs	$	1,458	$	1,154
Accrued compensation and benefits		803		2,421
Accrued professional service costs		303		480
Other accruals		413		252
Total accrued expenses and other current liabilities	$	2,977	$	4,307

Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2026	May 13, 2026
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2026
Document Fiscal Year Focus	2026
Document Fiscal Period Focus	Q1
Trading Symbol	APVO
Entity Registrant Name	APTEVO THERAPEUTICS INC.
Entity Central Index Key	0001671584
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Document Transition Report	false
Document Quarterly Report	true
Entity Interactive Data Current	Yes
Entity Common Stock, Shares Outstanding		1,246,105
Title of 12(b) Security	Common Stock, $0.001 par value per share
Security Exchange Name	NASDAQ
Entity Address, Address Line One	2401 4th Avenue
Entity Address, Address Line Two	Suite 1050
Entity Address, City or Town	Seattle
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98121
City Area Code	206
Local Phone Number	838-0500
Entity Incorporation, State or Country Code	DE
Entity Current Reporting Status	Yes
Entity Tax Identification Number	81-1567056
Entity File Number	001-37746