PharmAthene and Theraclone Sciences, a privately-held monoclonal antibody (mAb) discovery and development company, have signed a definitive merger agreement.

The all-stock transaction has been unanimously approved by both boards of directors and is subject to shareholder and regulatory approval. PharmAthene will issue shares of PharmAthene common stock to Theraclone stockholders; Theraclone stockholders will own 50% of the combined company.

Clifford J. Stocks, chief executive officer of Theraclone, will be president and CEO of the merged company.  Eric I. Richman will become director of the combined company's board.

The company will be a fully-integrated and diversified biologics company with four clinical-stage product candidates targeting high-value commercial and government markets. It will combine vaccine and human monoclonal antibody expertise with a focus on infectious diseases and oncology, and will have a discovery pipeline with four preclinical programs and multiple discovery candidates, along with three partnered products.

Clinical stage product candidates following the merger will be TCN-202 CMV antibody being developed for the prevention and treatment of human cytomegalovirus (CMV) infections, TCN-032 influenza antibody being developed for the treatment of pandemic and severe seasonal influenza, SparVax anthrax vaccine and Valortim anthrax anti-toxin.

The merged company will feature a preclinical pipeline driven by the proprietary I-STAR memory B-cell interrogation platform, which facilitates the discovery of human antibodies against novel targets. Theraclone has an established collaboration with Pfizer for specific infectious disease and oncology indications for which it has received upfront payments and research funding and may receive development and commercialization milestones and royalties on product sales in the future based on successful advancement.