Under pressure to satisfy partner Pfizer Inc.'s demands for increased volumes of the ONYX-015 cancer compound, Onyx Pharmaceuticals Inc. decided that its own needs had diverged too much from the pharma company's interest in developing the engineered adenovirus. The solution was to regain control over the compound.

ONXX had been scrambling to come up with sufficient compound since PFE acquired ONXX's original partner Warner-Lambert last year. Phase III studies in the head and neck indication started in June last year, but those trials weren't a priority for PFE, which was interested in larger indications, according to Helen Kim, senior vice president of corporate development at ONXX (Richmond, Calif.).