APVO442 Prostate Cancer Data Presented at the American Association for Cancer Research Annual Meeting

Preclinical Data Support Potential for APVO442 in Difficult-to-Treat Types of Prostate Cancer, Including Metastatic Castration-Resistant Disease

SEATTLE, WA / ACCESSWIRE / April 12, 2022 / Aptevo Therapeutics Inc. (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 the presentation of preclinical data for APVO442 in a poster session at the American Association for Cancer Research (AACR) Annual Meeting in New Orleans, LA. APVO442 is a bispecific therapeutic candidate targeting prostate-specific maturation antigen (PSMA) and CD3 designed to redirect the patient's T cell-mediated tumor-fighting responses against PSMA-expressing solid tumors (prostate cancer).

The presentation, entitled "APVO442 is a distinct PSMA x CD3 targeted bispecific candidate designed to optimize T cell fitness and distribution to solid tumors," highlights the potential of APVO442 to treat prostate cancer indications such as metastatic castration-resistant prostate cancer with increased benefit and decreased side effects relative to other potential therapeutics in the bispecific category. Aptevo is working to identify a clinical path for APVO442 and to potentially offer improved treatment options as a monotherapy or combination therapy for patients with difficult-to-treat prostate cancers.

"APVO442 was designed to offer unique tumor fighting and safety properties with the goal of maximizing the patients' own immune response toward tumor killing while minimizing the toxic effects that can be associated with this bispecific therapeutic category, most notably cytokine release syndrome. This is a serious and sometimes treatment-limiting side effect in a clinical setting," said Michelle Nelson, Associate Director of Immunobiology, Aptevo Therapeutics. "We are continuing preclinical studies to support an IND-enabling package, which precedes the start of human clinical studies. The Company looks forward to presenting additional APVO442 data, our first candidate developed using our innovative APDAPTIR-FLEX platform."

About APVO442

APVO442 is a bispecific antibody candidate designed to target Prostate Specific Membrane Antigen (PSMA), a tumor antigen that is highly expressed on prostate cancer cells with limited normal tissue expression, and CD3, a signaling component of the T-cell receptor complex. APVO442 contains two binding domains to PSMA to increase binding to this tumor antigen, and a single, lower affinity binding domain to CD3. The bispecific candidate is designed to induce target-specific T-cell killing of PSMA positive cancer cells while improving concentration of the drug at the tumor site. The drug candidate is built on Aptevo's ADAPTIR-FLEX platform and leverages the unique properties of this technology to increase binding to PSMA while lowering binding to T cells in the circulation. This design has potential to increase the amount of drug concentration at the site of PSMA-positive tumors and increase anti-tumor responses by tumor-infiltrating T cells.

About Aptevo Therapeutics Inc.

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, its expectations regarding the effectiveness of its ADAPTIR and ADAPTIR-FLEX platforms, whether APVO442 can offer improved treatments options for patients with prostate cancer, statements relating to Aptevo's clinical programs, 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 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 results of pre-clinical studies being predictive of the results of later-stage clinical trials, expectations for the timing and steps required in the IND filing and regulatory review process, including our ability to obtain regulatory clearance to commence clinical trials, expectations for regulatory approvals, the impact of competitive products, our ability to enter into agreements with strategic partners and other matters that could affect the availability or commercial potential of Aptevo's product candidates, business or economic disruptions due to catastrophes or other events, including natural disasters or public health crises such as the coronavirus (referred to as COVID-19), and geopolitical risks, including the current war between Russia and Ukraine. 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, 2021, 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.

CONTACT:
Miriam Weber Miller
Aptevo Therapeutics
Email: IR@apvo.com or Millerm@apvo.com
Phone: 206-859-6628

SOURCE: Aptevo Therapeutics