Pfizer reported today top-line results from ORAL Start (A3921069), a phase III study of the investigational agent tofacitinib, a novel, oral Janus kinase (JAK) inhibitor for the treatment of adults with moderate-to-severe active rheumatoid arthritis (RA).

ORAL Start, an ongoing two-year randomized comparative study in methotrexate (MTX)-naïve patients with moderate-to-severe active RA, dosed 958 patients with tofacitinib 5mg or 10 mg twice-daily (BID) as monotherapy or MTX. The study met its primary endpoints at both the 5mg and 10 mg BID doses. Tofacitinib was found to be superior to MTX with statistically significant changes shown in inhibiting structural damage, as measured by change from baseline in modified Total Sharp Score (mTSS), and in reducing signs and symptoms of RA, as measured by ACR70 response rates. Both primary endpoints assessed tofacitinib versus MTX at six months. The data reported are from a planned analysis at one year.

No new safety signals emerged in the ORAL Start study. The most common adverse events were infections, including tuberculosis and herpes zoster; malignancies, including lymphoma; decreased neutrophil counts and neutropenia; and lipid elevations.