Emergent BioSolutions Announces Positive Preclinical Efficacy and PK Data for Its New Bispecific Adaptir Protein Therapeutic ES414 at AACR

Emergent BioSolutions Inc. (NYSE: EBS) today announced that two posters on the development of its lead bispecific ADAPTIR^TM (Modular Protein Technology) molecule, ES414, were presented earlier this week at the American Association for Cancer Research annual meeting in Washington, D.C.

The ES414 molecule was constructed using Emergent’s ADAPTIR technology platform and selectively binds to the T cell receptor on cytotoxic T cells and Prostate Specific Membrane Antigen (PSMA), an antigen commonly found on prostate cancer cells. In preclinical studies, ES414 has been shown to redirect T-cell cytotoxicity (RTCC) towards prostate cancer cells expressing PSMA. ES414 is being developed as a potential therapeutic for castrate-resistant prostate cancer.

In the first poster, Emergent scientists described the efficacy of ES414 to prevent growth of human prostate cancer cells in vivo that express the PSMA protein on their surface:

• “Anti-PSMA x anti-CD3 ADAPTIR molecule inhibits tumor growth in vivo”
  • Treatment with ES414 showed statistically significant inhibition of subcutaneous tumor outgrowth in the presence of human T cells in two independent mouse xenograft models of prostate cancer (C4-2B, MDA-PCa-2b). In both models, all treatment groups also showed a statistically significant decrease in serum PSA compared to negative controls.

The second poster described initial PK and tolerability:

• “Pharmacokinetic evaluation and tolerability assessment of anti-PSMA x anti-CD3 ADAPTIR molecule”
  • These non-clinical studies showed that ES414 is pharmacologically active, has an extended serum half-life compared to antibody fragments, is well tolerated at levels well above the expected human dose, and possesses suitable characteristics for further in vivo toxicology studies.

“We were excited to present the results of these studies and were very pleased with the interest these data received at the meeting,” said Jane Gross, Ph. D., vice president of applied research at Emergent BioSolutions. “ES414 is a promising molecule. Non-clinical efficacy studies have shown that it is well tolerated. It can also be manufactured using standard methodologies. These findings certainly support further development of this molecule and have generated significant partnering interest in our product candidate.”

About Prostate Cancer

Prostate cancer is the most common cancer in men with approximately 230,000 new cases annually in the United States. Although screening, radiation, surgery and hormone ablation therapy have greatly improved the detection and treatment of early stage prostate cancer, few options exist to treat metastatic, castrate-resistant prostate cancer.

About the ADAPTIR™ Platform

ADAPTIR bispecific proteins are modular, single chain polypeptides that comprise two separate binding domains (VL and VH), a hinge segment, and an effector domain (huFc). They have a differentiated structure from monoclonal antibodies and can generate a unique signaling response. In addition, ADAPTIR proteins may mediate complement dependent cytotoxicity and Fc dependent cytotoxicity, similar to monoclonal antibodies.

ADAPTIR is the new trademark for Emergent BioSolutions Inc.’s modular protein technologies that were previously identified using the SCORPION^TM (multispecific protein therapeutic) and SMIP^TM (monospecific protein therapeutic) trademarks. ADAPTIR and any and all Emergent BioSolutions Inc. brand, product, service and feature names, logos and slogans are trademarks or registered trademarks of Emergent BioSolutions Inc. or its subsidiaries in the United States or other countries. All rights reserved.

About Emergent BioSolutions

Emergent BioSolutions is a specialty pharmaceutical company seeking to protect and enhance life by offering specialized products to healthcare providers and governments to address medical needs and emerging health threats. Additional information may be found at www.emergentbiosolutions.com. Follow us on twitter: @emergentbiosolu.

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, are forward-looking statements. Forward-looking statements in this press release include statements about the potential and therapeutic opportunity of the ADAPTIR molecule. These forward-looking statements are based on our current intentions, beliefs and expectations regarding future events. We 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 our 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, we do 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 the company’s actual results to differ materially from those indicated by such forward-looking statements, including the success of our ongoing and planned preclinical studies and clinical trials; the rate and degree of market acceptance and clinical utility of our products; the timing of and our ability to obtain and maintain regulatory approvals for our product candidates; and our commercialization, marketing and manufacturing capabilities and strategy. 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. Investors should consider this cautionary statement, as well as the risk factors identified in our periodic reports filed with the SEC, when evaluating our forward-looking statements.