Celldex Plunges After Pfizer Cancels Partnership for Brain Cancer Vaccine

Pfizer Inc. is pulling out of an agreement with Celldex Therapeutics Inc. to fund the development of an experimental brain tumor vaccine. Celldex shares fell the most in almost two years.

The vaccine called rindopepimut, or CDX-110, is “no longer a strategic priority of Pfizer,” which will return the rights to the therapy to Celldex Nov. 1, Needham, Massachusetts-based Celldex said today in a statement.

The treatment is in the second of three stages of testing generally required to win U.S. regulatory approval. New York- based Pfizer, the world’s biggest drugmaker, licensed rights to the product in 2008 from Celldex for as much as $440 million, plus royalties. If approved, the brain cancer vaccine could have $450 million in peak annual sales and come on the market in 2013, Joseph Pantginis, an analyst at Roth Capital, said in May.

“We see this as a tremendous opportunity for Celldex, our shareholders and patients,” said Chief Executive Officer Anthony Marucci, on a conference call with investors today. “We believe rindopepimut is very well-positioned to advance into pivotal clinical studies.”

Celldex fell $1.25, or 26 percent, to $3.53 at 4 p.m. in Nasdaq Stock Market trading. Celldex has no approved products, and the vaccine is its most advanced treatment in testing.

Funds Needed

Celldex will need to raise additional money to fund late- stage testing, Marucci said. The company, with 100 employees, had $65.8 million in cash and short-term assets as of June 30. Celldex doesn’t need another partner to move the drug forward in development, Marucci said.

The treatment is designed to ramp up the body’s immune response to fight off the tumor. The vaccine targets the molecule called epidermal growth factor receptor variant III, which plays a role in cell growth. The strategy could be applied to breast, ovarian and prostate cancer as well.

Pfizer spokesman Curtis Allen declined to comment on the specifics of why the drugmaker was terminating the agreement with Celldex.

“As part of Pfizer Oncology’s ongoing prioritization of assets across its broad research and development portfolio, the Company will be terminating its license and development agreement with Celldex Therapeutics for the investigational compound rindopepimut,” said Allen in an e-mailed statement. “Pfizer is working to transition the compound back to Celldex Therapeutics. Pfizer remains committed to research and development of new therapies for patients with cancer.”

Results from a study presented in May showed 70 percent of patients receiving the vaccine were alive without their cancer worsening about eight months after diagnosis. Typically, about half of patients with that type of tumor survive without the disease progressing during that time period. The finding, involving 40 patients, were from an interim analysis of a study.

To contact the reporter responsible for this story: Shannon Pettypiece at spettypiece@bloomberg.net.

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