Sanofi-aventis has entered an agreement to acquire BiPar Sciences, Inc., a privately held U.S. biopharmaceutical company developing tumor-selective approaches for the treatment of cancer, for as much as $500 million. Under the agreement, the purchase price will depend on the achievement of development milestones related to BiPar’s leading drug candidate, BSI-201, currently in Phase II trials for breast and ovarian cancer.

BiPar is developing tumor-selective cancer treatments in the emerging field of DNA repair that work by preventing cancer cells from repairing their own DNA using PARP (Poly ADP-Ribose Polymerase) inhibitors, causing cancer cell death.

“We are extremely pleased to join with one of the most successful and innovative global pharmaceutical companies,” said Hoyoung Huh, M.D., Ph.D., president and chief executive officer of BiPar Sciences. “This agreement validates BiPar’s novel scientific approach and will maximize patient access to this new class of breakthrough cancer therapy.”

“The acquisition of BiPar, one of the pioneer for novel tumor-selective therapies, is a further step in our company’s goal to focus on new approaches to strengthen our oncology R&D portfolio,” said Christopher A. Viehbacher, chief executive officer of Sanofi-aventis. “This acquisition illustrates our strong commitment to oncology to provide patients, physicians and public health stakeholders with breakthrough medicines addressing unmet medical needs.” The transaction is expected to close in 2Q09.