Swiss drugmaker Roche Holding said a late-stage study found its arthritis drug ocrelizumab helped ease symptoms of a type of rheumatoid arthritis.

The phase III trial evaluating ocrelizumab as a treatment for seropositive rheumatoid arthritis patients with a previous inadequate response to methotrexate (MTX) met its primary efficacy endpoint, Roche said.

The study showed that the drug in combination with MTX alleviated symptoms of the disease both at week 24 and week 48 more than in patients treated with MTX alone.

Rheumatoid arthritis is an autoimmune disease characterized by inflammation that leads to stiff, swollen and painful joints, Roche said.

More than 20 million people worldwide suffer from this disease, said Roche, the world's largest maker of cancer drugs.