Investors

SEATTLE, WA / ACCESSWIRE / October 26, 2021 / Aptevo Therapeutics Inc. ("Aptevo" or "the Company") (NASDAQ:APVO), a clinical-stage biotechnology company focused on developing novel immuno-oncology therapeutics based on its proprietary ADAPTIR™ and ADAPTIR-FLEX™ platform technologies, today announced that the peer-reviewed journal Cancers published results of the Company's research on mitigation of the risk of cytokine release syndrome (CRS) as well as its effective management in patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) who are treated with APVO436, a bispecific antibody that has been engineered to redirect patients' immune system against their cancer cells. Dr. Fatih Uckun, a leukemia expert and Chief Clinical Advisor to Aptevo, is the lead author of the newly published article.

CRS is a potentially life-threatening complication of therapy with T-cell engaging bispecific antibodies. This study was undertaken to evaluate the risk, characteristics and biomarkers of treatment-emergent CRS in patients with relapsed/refractory AML or MDS who received weekly intravenous infusions of the CD3xCD123 bispecific antibody APVO436. According to the study, with the risk mitigation strategies put in place, only 10 of 46 patients (21.7%) treated with APVO436 developed CRS, which is considered a common side effect of bispecific antibodies. Further, the incidence of severe (Grade 3) or life threatening (Grade 4) CRS was only 8.7% (4 of 46 patients). The authors reported that CRS led to dose interruptions of APVO436 in 4 of 46 patients, a dose reduction in one patient and permanent discontinuation of the study drug in only one patient. In most cases, CRS events were transient and medically manageable with standard of care.

AML and MDS are very common forms of blood cancer in adults. Patients with AML or MDS who relapse following available standard of care treatments have a dismal prognosis and they are in urgent need for new treatment options. Aptevo believes that APVO436 may provide an important new option treating these cancers.

"We continue to learn more about the potential clinical impact of our lead leukemia drug candidate, APVO436, and we are hopeful that its continued development will provide the foundation for a more effective combination therapy as a new standard of care regimen that is less likely to fail," added Mr. Marvin White, the CEO of Aptevo.

About the Publication
The article, "Risk, Characteristics and Biomarkers of Cytokine Release Syndrome in Patients with Relapsed/Refractory AML or MDS Treated with CD3xCD123 Bispecific Antibody APVO436." has been published in Cancers as part of the Special Issue "Acute Myeloid Leukemia (AML)" and is available as follows:

Abstract: https://www.mdpi.com/2072-6694/13/21/5287

HTML Version: https://www.mdpi.com/2072-6694/13/21/5287/htm

PDF Version: https://www.mdpi.com/2072-6694/13/21/5287/pdf

Special Issue: https://www.mdpi.com/journal/cancers/special_issues/Acute_Myeloid_Leukemia_AML

Citation Reference: Uckun, F.M.; Watts, J.; Mims, A.; Patel, P.; Wang, E.; Shami, P.; Cull, E.; Lee, C.; Cogle, C.R.; Lin, T.L. Risk, Characteristics and Biomarkers of Cytokine Release Syndrome in Patients with Relapsed/Refractory AML or MDS Treated with CD3xCD123 Bispecific Antibody APVO436. Cancers 13, no. 21: 5287. https://doi.org/10.3390/cancers13215287

About APVO436
Overexpression of CD123 is the hallmark of many forms of leukemia. Aptevo's lead proprietary drug candidate, APVO436 is a bispecific CD3xCD123 ADAPTIR that is designed to redirect the immune system of the patient to destroy leukemia cells expressing the target CD123 molecule on their surface. This antibody-like recombinant protein therapeutic is designed to engage both leukemia cells and T-cells of the immune system and bring them closely together to trigger the destruction of leukemia cells. APVO436 has been engineered using Aptevo's proprietary and enabling bioengineering methods and is designed to reduce the likelihood and severity of CRS. APVO436 has received orphan drug designation ("orphan status") for AML according to the Orphan Drug Act.

About Aptevo Therapeutics 
Aptevo Therapeutics Inc. is a clinical-stage biotechnology company focused on developing novel immunotherapies for the treatment of cancer. Aptevo is seeking to improve treatment outcomes of cancer patients. For more information, please visit www.aptevotherapeutics.com.

Safe Harbor Statement
This press release includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements, other than statements of historical fact, including, without limitation, Aptevo's expectations about the activity, efficacy and safety of its therapeutic candidates and potential use of any such candidates as therapeutics for treatment of disease, advancement of its clinical trials and its expectations regarding the effectiveness of its ADAPTIR and ADAPTIR-FLEX platforms, and any other statements containing the words "may," "believes," "expects," "anticipates," "hopes," "intends," "optimism," "potential," "designed," "engineered," "breakthrough," "innovative," "innovation," "promising," "plans," "forecasts," "estimates," "will" and similar expressions are intended to identify forward-looking statements. These forward-looking statements are based on Aptevo's current intentions, beliefs, and expectations regarding future events. Aptevo cannot guarantee that any forward-looking statement will be accurate. Investors should realize that if underlying assumptions prove inaccurate or unknown risks or uncertainties materialize, actual results could differ materially from Aptevo's expectations. Investors are, therefore, cautioned not to place undue reliance on any forward-looking statement.

There are several important factors that could cause Aptevo's actual results to differ materially from those indicated by such forward-looking statements, including a deterioration in Aptevo's business or prospects; adverse developments in clinical development, including unexpected safety issues observed during a clinical trial; adverse developments in the U.S. or global capital markets, credit markets or economies generally; and changes in regulatory, social, and political conditions. For instance, actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including the uncertainties inherent in the initiation and enrollment of clinical trials, availability and timing of data from ongoing clinical trials, expectations for the timing and steps required in the regulatory review process, including our ability to obtain regulatory clearance to commence clinical trials, expectations for regulatory approvals, the impact of competitive products, actions of activist stockholders, our ability to enter into agreements with strategic partners and other matters that could affect the availability or commercial potential of the Company's product candidates, business or economic disruptions due to catastrophes or other events, including natural disasters or public health crises such as the novel coronavirus (referred to as COVID-19). These risks are not exhaustive, Aptevo faces known and unknown risks. Additional risks and factors that may affect results are set forth in Aptevo's filings with the Securities and Exchange Commission, including its Annual Report on Form 10-K for the fiscal year ended December 31, 2020, and its subsequent reports on Form 10-Q and current reports on Form 8-K. The foregoing sets forth many, but not all, of the factors that could cause actual results to differ from Aptevo's expectations in any forward-looking statement. Any forward-looking statement speaks only as of the date of this press release, and, except as required by law, Aptevo does not assume any obligation to update any forward-looking statement to reflect new information, events, or circumstances.

CONTACTS:
Investors
Miriam Weber Miller
Aptevo Therapeutics
Email: IR@apvo.com / Millerm@apvo.com
Phone: 206-859-6629

Media
Jules Abraham
JQA Partners
Email: jabraham@jqapartners.com
Phone: 917-884-7378

SOURCE: Aptevo Therapeutics