Positive new data for Pfizer's tofacitinib; possible regulatory delay

Pfizer (NYSE:PFE), the world’s largest drugmaker by sales, yesterday released positive  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 study in methotrexate (MTX)-naive patients with moderate-to-severe active RA, randomized to receive tofacitinib 5mg or 10mg twice-daily (BID) as monotherapy or MTX, met its primary endpoints at both dosages. 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, and the safety profile of tofacitinib remained consistent with that seen previously in the clinical development program. Safety findings observed in the overall tofacitinib RA program include serious and other important infections, including tuberculosis and herpes zoster; malignancies, including lymphoma; decreased neutrophil counts and neutropenia; and lipid elevations. A detailed analysis of the ORAL Start findings will be submitted to a future scientific meeting.