SEATTLE, Oct. 02, 2017 (GLOBE NEWSWIRE) -- Aptevo Therapeutics Inc. (Nasdaq:APVO), a biotechnology company
focused on developing novel immuno-oncology and hematology therapeutics, today announced that new information on the Company’s
proprietary next generation ADAPTIR™ protein therapeutic platform was presented at the 8th Annual World Bispecific
Summit in Boston, MA, September 26-28, 2017.
In a presentation entitled, “ADAPTIR™ Platform: Rapid Development of Novel Protein Therapeutics,” Dr.
Peter Pavlik, Principal Scientist at Aptevo, presented a comprehensive overview of Aptevo’s next generation ADAPTIR platform,
highlighting improvements that have led to the development of new ADAPTIR candidates with increased stability, superior
manufacturability and antibody expression levels, and an extended half-life of up to 12.5 days in rodents.
In his overview, Dr. Pavlik describes the expansion of Aptevo’s ADAPTIR platform into several different
mechanisms of action, including, T-cell engagers targeting CD3; a bispecific targeting the costimulatory receptor 41BB and a solid
tumor antigen; and a bispecific that targets a cytokine to specific cells via an ADAPTIR platform. This evolution highlights
the flexible and versatile nature of the ADAPTIR platform and its utility in generating multiple bispecific candidates.
These attributes have been demonstrated with Aptevo’s next generation lead bispecific T-cell engager, APVO436,
which simultaneously targets CD123 (a cell surface receptor highly expressed in several hematological malignancies) and CD3 (a
T-cell co-receptor that promotes cytotoxicity.) Data from preclinical studies of APVO436 show that it:
- Potently and selectively induces tumor-specific immune responses and T-cell mediated cytotoxicity in vitro and
in vivo
- Has an antibody-like serum half-life in mice of up to 12.5 days – significantly longer than first generation ADAPTIR
candidates and other bispecific candidates in development
- Induces potent, dose-dependent T-cell mediated lysis (killing) of CD123-expressing acute myelogenous leukemia (AML) cell
lines, accompanied by target-specific T-cell activation and proliferation
- Possess low (nM) binding affinity; binds with high affinity to human and cynomolgus CD123-expressing cells with
EC50 values in the low nanomolar range
- Dose-dependently inhibits tumor growth and significantly prolongs survival compared to vehicle-treated animals in a Xenograft
tumor model of AML
“Our data on APVO436 confirm the important advances we have made with our next generation ADAPTIR candidates,
specifically improved stability, half-life, activity and manufacturability – all critical attributes for commercialization,” said
Jane Gross, Ph.D., Senior Vice President and Chief Scientific Officer. “We have also reduced sequences that could lead to
immunogenicity in the clinic. Our next generation candidates, like APVO436, are designed to be delivered by intravenous
dosing. With two ADAPTIR candidates currently in clinical development, and a broad portfolio of bispecifics advancing in
preclinical development, Aptevo has a rich pipeline of assets in the emerging field of targeted antibody therapeutics.”
ADAPTIR Bispecific Antibody Platform: Differentiating Characteristics
- Unique Homodimer Structure - simplifies candidate generation; facilitates rapid substitution of target binding
domains to evaluate numerous candidates simultaneously
- Bivalent for Both Binding Domains - increases the avidity and potency of ADAPTIR candidates
- Unique IgG Fc ‘Backbone’ - extends the half-life of ADAPTIR molecules (up to ~12.5 days in rodents)
- Antibody-like Production Processes – demonstrated capability to produce up to 2.0g/L comparable to traditional
antibody manufacturing processes
- Improved Yield and Cost of Goods - use of a single gene and ease of CHO cell line production enhances ADAPTIR
bispecific manufacturing productivity
ADAPTIR Clinical and Preclinical Portfolio:
- APVO414 – a bispecific ADAPTIR candidate, currently in Phase 1 development, targeting prostate specific
membrane antigen (PSMA), an enzyme that is expressed on the surface of prostate cancer cells, and, CD3, a component of the T cell
receptor complex expressed on all T cells. APVO414 redirects T cells to specifically kill PSMA expressing tumors and is
being developed for metastatic castration-resistant prostate cancer, which is advanced prostate cancer that has spread to other
organs and no longer responds to hormone blocking therapies.
- Otlertuzumab – a monospecific ADAPTIR candidate currently in Phase 2 development for the treatment of
chronic lymphocytic leukemia (CLL). Data from a Phase 2 clinical trial evaluating otlertuzumab in combination with
bendamustine, compared to bendamustine alone, demonstrated a significant increase in median progression free survival for the
combination, from approximately 10 to 16 months.
- APVO436 – a bispecific ADAPTIR candidate currently in preclinical development targeting CD123, a cell
surface receptor highly expressed on several hematological malignancies and CD3, a component of the T-cell receptor. APVO436
engages T cells to kill tumor cells.
- ALG.APV-527 – a bispecific antibody candidate, partnered with Alligator Bioscience, featuring a novel
mechanism of action designed to simultaneously target 4-1BB (CD137) and an undisclosed tumor antigen. 4-1BB, a
costimulatory receptor on T cells, is known to enhance the immune response to cancer through activation of tumor-specific T cells
and is believed to be a promising target for new immunotherapeutic approaches. ALG.APV-527 could potentially have utility in the
treatment of a broad spectrum of cancers over-expressing the tumor antigen, including breast, cervical, non-small-cell-lung,
prostate, renal, gastric, colorectal and bladder cancers.
- APVO210 – a bispecific ADAPTIR preclinical candidate with a novel mechanism of action based on targeted
cytokine delivery. APVO210 is composed of a humanized anti-CD86 antibody fused with a modified form of IL-10 that
specifically induces IL-10 signaling on antigen presenting cells, but not on lymphoid populations. APVO210 functions by
suppressing immune responses and inducing certain tolerogenic responses and therefore may have potential benefit for the
treatment of autoimmune and inflammatory diseases.
- ROR1 Bispecific – a proof-of-concept bispecific candidate targeting ROR1, an antigen found on several solid
tumors and hematologic, or blood-related malignancies. Initial preclinical data demonstrate redirected T cell killing of
tumors expressing ROR1 in vitro and in vivo in animal models.
About Aptevo Therapeutics Inc.
Aptevo Therapeutics Inc. is a clinical-stage biotechnology company focused on novel oncology and hematology
therapeutics to meaningfully improve patients’ lives. Aptevo has a commercial product, IXINITY®, approved and
marketed in the United States for the treatment of Hemophilia B, and a versatile core technology – the ADAPTIR™ modular protein
technology platform capable of generating highly-differentiated bispecific antibodies with unique mechanisms of action to treat
cancer or autoimmune diseases. Aptevo has two ADAPTIR antibody candidates currently in clinical development and a broad
pipeline of novel investigational-stage bispecific antibody candidates focused in immuno-oncology and autoimmune disease and
inflammation. 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. Any statements, other than statements of historical fact, including, without limitation, statements regarding
potential milestone payments, Aptevo’s outlook, financial performance or financial condition, Aptevo’s technology and related
pipeline, collaboration and partnership opportunities, commercial portfolio, 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 Aptevo’s 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 closing of the transaction;; a deterioration in Aptevo’s business or prospects; the parties may be
unable to achieve the anticipated benefits of the transaction; 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 Aptevo’s filings with the Securities and Exchange Commission, including its most recent Annual
Report on Form 10-K, as filed on March 31, 2017, 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.
For Further Information:
Aptevo Therapeutics
Stacey Jurchison
Senior Director, Investor Relations and Corporate Communications
206-859-6628
JurchisonS@apvo.com