Roche says that a late-stage study of ocrelizumab in patients with seropositive rheumatoid arthritis has met its primary endpoint of showing an improvement in the signs and symptoms of the disease when combined with methotrexate, compared to those who received the latter drug alone.

The Phase III STAGE study, which was conducted in 1,015 patients, 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. While overall adverse events were comparable between ocrelizumab and placebo treatment groups, a higher percentage of serious infections was observed in the Roche drug. Safety analyses are ongoing and will be presented, along with the full STAGE results, at a future scientific conference.

Roche noted that the results from this first Phase III trial in RA build on findings from previous Phase II studies and confirm that targeting seropositive RA patients with ocrelizumab, which is a humanised anti-CD20 therapy, can lead to an improvement in symptoms. Results from three additional Phase III trials will become known in the first half of 2010.

William Burns, Roche’s head of pharmaceuticals, said “we believe ocrelizumab has the potential to offer a differentiated treatment option for these patients”. The treatment is a follow-up to the blockbuster MabThera/Rituxan (rituximab), which is a part human/part mouse antibody which, like ocrelizumab, has been developed with Biogen Idec.