Mixed phase 3 results for AstraZeneca’s arthritis drug

Hannah Blake

pharmaphorum

AstraZeneca has announced mixed results for phase 3 clinical trials that were evaluating the safety and efficacy of fostamatinib, the first oral spleen tyrosine kinase (SYK) inhibitor in development for rheumatoid arthritis (RA).

The OSKIRA-1 clinical trial had two primary endpoints. Fostamatinib showed a statistically significant improvement in measuring signs and symptoms of RA, measured by ACR20 response rates. However, the drug did not demonstrate any significant difference in the second endpoint, which was an X-ray endpoint known as mTSS (modified Total Sharp Score).

“These top-line results provide important information on the efficacy and safety of fostamatinib and demonstrate that the compound has an effect on the signs and symptoms of rheumatoid arthritis. We will await the results of the remaining Phase III studies, OSKIRA-2 and OSKIRA-3, to further evaluate and characterise the profile of fostamatinib as a potential treatment for rheumatoid arthritis.”

Briggs W. Morrison, MD, Executive Vice President of Global Medicines Development and Chief Medical Officer.

These mixed results may add to concerns that AstraZeneca’s fostamatinib lacks commercial potential. The drug is up against Abbott Laboratories’ Humira and Pfizer’s Xeljanz in a market worth over US $20 billion.