Bristol Myers Squibb said on Thursday it plans to double the number of treatments it is testing in clinical trials, with a focus on cell therapies, over the next 18 months, as it contends with increasing generic competition for two of its top-selling drugs.

The drugmaker, which currently has six candidates in trials, will advance six more in its research pipeline - including three cell therapies that target immune system disorders and different types of cancer.

The New York-based company has been pressured by declining demand for two of its top drugs, the blood cancer treatment Revlimid and blood thinner Eliquis, which face generic competition.

Bristol and partner Pfizer's blood thinner Eliquis was also on the list of 10 drugs that will be subject to the first-ever price negotiations by the U.S. Medicare health program.

The company recently received regulatory approval for a new cell therapy manufacturing facility in Devens, Massachusetts and Bristol said it will continue expanding its manufacturing capacity.

Bristol, which already has two approved cell therapies in the U.S., Breyanzi and Abecma, targeting different blood cancer indications, said it plans to continue development for treatment of other diseases such as lupus erythematosus and multiple sclerosis.

The drugmaker is hosting an R&D day on Thursday, where executives are expected to provide details of the company's research strategy.

(Reporting by Pratik Jain in Bengaluru; Editing by Krishna Chandra Eluri)