GREG KELLER AP Business Writer PARIS (AP) — Sanofi-Aventis SA has agreed to pay up to $500 million to buy California-based BiPar Sciences in a move to strengthen its research and development in cancer treatments, the Paris-based pharmaceutical company said Wednesday. BiPar Sciences, based in Brisbane, California, is focused on research into a new cancer treatment that blocks tumor cells from repairing their own DNA, causing the cancer cells to die, Sanofi-Aventis said in a statement. The final price paid for BiPar Sciences will depend on its achieving targets related to the development of the new treatment, known as BSI-201, Sanofi-Aventis said. BiPar is owned by private capital firms including Domain Associates, Canaan Partners and Vulcan Capital, according to the company's web site. Other major investors in the company include Polytechnos, Quantum Technology Partners and Lighthouse Capital Partners. Wednesday's deal is the latest in a string of recent purchases Sanofi-Aventis has made around the world since the arrival last December of its new chief executive, Chris Viehbacher. This month alone, Sanofi-Aventis has agreed to buy Sao Paulo-based generic drug maker Medley, Brazil's third-largest pharmaceutical company, and Laboratorios Kendrick, a Mexican generic drug maker with annual sales of around €26 million. In the United States, the recession is boosting sales of generic drugs, which cost 30 percent to 80 percent less than the original brand-name ones. The number of prescriptions for generic drugs jumped 8 percent last year, and they now account for 68 percent of all prescriptions filled, according to the Generic Pharmaceutical Association. Viehbacher has said he aims to turn Sanofi-Aventis into "a diversified global leader in health care" and that he would look for small to medium-sized acquisitions as one way of acheiving this. In February the company named Laurence Debroux to the newly created position of Chief Strategic Officer to lead Sanofi-Aventis' hunt for acquisitions. In mid-day trading in Paris Sanofi-Aventis shares were up 1.2 percent at €41.32 ($54.74).