Aptevo Therapeutics Announces Publication of Phase 2 Clinical Data for Otlertuzumab

Data Show Improved Overall Response Rate and Progression Free Survival with Combination Otlertuzumab/Bendamustine Therapy

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| Source: Aptevo Therapeutics

SEATTLE, Dec. 16, 2016 (GLOBE NEWSWIRE) -- Aptevo Therapeutics Inc. (Nasdaq:APVO) a biotechnology company focused on developing novel oncology and hematology therapeutics, today announced the publication of positive data from a Phase 2 clinical trial evaluating its proprietary humanized monospecific anti-CD37 protein therapeutic, otlertuzumab. The results were recently published in the British Journal of Haematology (BJH).

“We’re very encouraged by the Phase 2 data, which demonstrated a significant increase in median progression free survival, from approximately 10 to 16 months in patients receiving combination otlertuzumab/bendamustine therapy,” said Marvin L. White, President and Chief Executive Officer.  “These data, coupled with additional results from ongoing studies of otlertuzumab used in combination with current CLL therapies should help position otlertuzumab for a potential partnership to advance into Phase 3 clinical development.”

The publication, entitled, “Randomized Phase 2 Study of Otlertuzumab and Bendamustine Versus Bendamustine in Patients with Relapsed Chronic Lymphocytic Leukemia,” discusses the results of a multi-center Phase 2 clinical trial comparing the efficacy and safety of otlertuzumab in combination with bendamustine to bendamustine alone in patients with relapsed chronic lymphocytic leukemia (CLL). The data show an improved overall response rate and progression free survival with combination otlertuzumab/bendamustine therapy.

“While substantial advances in the treatment of CLL have been made over the last several years, there is still a significant unmet medical need for safe and effective new combination therapies to treat the many CLL patients that eventually will experience a relapse or discontinue therapy due to adverse events,” remarked Dr. Scott Stromatt, Chief Medical Officer for Aptevo.  “These latest data show the combination of otlertuzumab and bendamustine is well tolerated and significantly increases the response rate and PFS in patients with relapsed or refractory CLL.  Consequently we are now exploring the utility of otlertuzumab in combination with additional CLL therapies to evaluate clinical benefit in distinct CLL patient subgroups.”

The data published in BJH suggest that combination therapy with otlertuzumab may improve outcomes for CLL patients. In previous studies Aptevo has shown that otlertuzumab in combination with rituximab, obintuzumab or idelalisib is clinically active and appears to have a good safety and tolerability profile.  Based on this promising body of data, Aptevo is further exploring its utility in subgroups of CLL patients who have either (i) not achieved a complete response after one year of therapy with ibrutinib, or (ii) in patients who are developing a resistant clone to ibrutinib but have not yet experienced a clinical relapse.

About the Phase 2 Clinical Trial
A total of 65 patients participated in the study with 32 receiving a combination of otlertuzumab and bendamustine and 33 receiving bendamustine alone.  The primary endpoint in the clinical trial was overall response rate (ORR), as measured by the 2008 International Workshop on CLL. Secondary endpoints included an assessment of progression free survival (PFS) and safety.

Phase 2 Clinical Trial Results
The study demonstrated that otlertuzumab combined with bendamustine significantly increased overall response rate, which was 69% for the combination compared to 39% for bendamustine alone (p=0.025).  In addition, the combination showed an improvement in median progression free survival, which was 15.9 months in the otlertuzumab/bendamustine combination treatment arm compared to 10.2 months in the bendamustine treatment arm (p=0.0192).  Otlertuzumab in combination with bendamustine was generally well tolerated, although there was a higher incidence of pyrexia (34% vs. 12%) and neutropenia (59% vs. 39%) with the combination, however, this did not result in a higher incidence of severe (grade 3 or 4) infections.

The full publication in the British Journal of Haematology can be accessed online at http://onlinelibrary.wiley.com/doi/10.1111/bjh.14464/full.

About Aptevo Therapeutics Inc.
Aptevo Therapeutics Inc. is a biotechnology company focused on novel oncology and hematology therapeutics to meaningfully improve patients’ lives. Our core technology is the ADAPTIR™ (modular protein technology) platform. Aptevo has four commercial products in the areas of hematology and infectious diseases, as well as various investigational stage product candidates in immuno-oncology.

Safe Harbor Statement
This press release includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Any statements, other than statements of historical fact, including, without limitation, statements regarding the potential opportunities, our technology and related pipeline, collaboration and partnership opportunities and their financial implications and any other statements containing the words “believes,” “expects,” “anticipates,” “intends,” “plans,” “forecasts,” “estimates,” “will” and similar expressions are 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. Any forward-looking statement speaks only as of the date of this press release, and, except as required by law, Aptevo does not undertake to update any forward-looking statement to reflect new information, events or circumstances.

There are a number of important factors that could cause our actual results to differ materially from those indicated by such forward-looking statements, including possible negative effects on our business operations, assets or financial results as a result of the separation; a deterioration in our business or prospects; adverse developments in our customer-base or markets; adverse developments in the U.S. or global capital markets, credit markets or economies generally; and changes in regulatory, social and political conditions. Additional risks and factors that may affect results are set forth in our filings with the Securities and Exchange Commission, including Aptevo’s most recent Quarterly Report on Form 10-Q, as filed on November 14, 2016. The foregoing sets forth many, but not all, of the factors that could cause actual results to differ from our expectations in any forward-looking statement. 

Source: 
Aptevo Therapeutics
Stacey Jurchison
Senior Director, Investor Relations and Corporate Communications
206-859-6628
JurchisonS@apvo.com