Genentech Inc recently acquired U.S. rights to a new drug, called GA101, from Roche Holding AG - the Swiss drugmaker that has a majority stake in the U.S. biotech - and together with Biogen Idec, Genentech has announced the two companies will be jointly developing this experimental cancer drug.

Biogen said it opted to help develop GA101 pursuant to terms of its ongoing Rituxan collaboration with Genentech, and will make an upfront payment of $ 31.5 million dollars to its larger partner and record it as a fourth-quarter charge.

The companies will share operating profits and losses in the U.S., Biogen said, while Roche retains rights in other markets.

Additional terms were not disclosed.

Like the controversial Rituxan/Mabthera, GA101 works by targeting immune system cells known as CD20-positive B cells. It is being studied in early-stage trials for non-Hodgkins lymphoma and chronic lymphocytic leukemia, another type of blood cancer, Biogen said.

Biogen stated Roche would provide an update on Phase 1 data for the new medicine at a medical meeting in December.