Merck KGaA's says cancer vaccine safe in study

FRANKFURT, May 30 (Reuters) - Merck KGaA's (MRCG.DE) experimental cancer vaccine Stimuvax proved safe to use in a long-term Phase II study on lung cancer patients, the German drugmaker said on Saturday.

The trial showed that patients' immune systems did not turn on normal cells, a major concern in new vaccines that are designed to prime the body's immune system to detect and attack cancer cells.

The study involved lung-cancer patients whose tumours had started to spread and long-term data was derived from 16 participants treated for between two and eight years.

The most common side effects were mild injection site reactions and nausea, according to a statement from Merck.

Results from the Phase II study encouraged Merck in February 2007 to take Stimuvax, which it co-develops with U.S. biotech firm Oncothyreon (ONTY.O), to the third and last phase of testing usually required for regulatory approval.

Germany's Merck is racing with biotech firms including Transgene (TRNG.PA), Dendreon Corp (DNDN.O) and Antigenics (AGEN.O) to bring cancer vaccines to market.

While Transgene's TG4010 compound also targets lung tumours, the most common form of cancer, the Dendreon and Antigenics drug candidates are aimed at prostate cancer and brain cancer, respectively. (Reporting by Ludwig Burger; Editing by Dhara Ranasinghe)