Mixed Results With RA Drug Fostamatinib in Phase III Trial
Only one of two endpoints met (Apr. 5)
Results have been announced from a phase III study of fostamatinib (AstraZeneca), the first oral spleen tyrosine kinase (SYK) inhibitor in development for rheumatoid arthritis (RA). The OSKIRA-1 trial had two primary endpoints: improvement in the signs and symptoms of RA, as measured by the American College of Rheumatology 20% improvement criteria (ACR20), and the modified Total Sharp Score (mTSS), an X-ray endpoint.
Statistically significant improvements in the ACR20 response rate were achieved at 24 weeks in patients treated with fostamatinib 100 mg twice daily and in patients treated with fostamatinib 100 mg twice daily for 4 weeks followed by 150 mg once daily, both in combination with methotrexate, compared with a group given placebo (49% [P < 0.001] and 44% [P = 0.006] vs. 34%, respectively).
However, fostamatinib did not demonstrate a statistically significant difference in mTSS compared with placebo at 24 weeks for either dosage (P = 0.252 and P = 0.170, respectively).
The most common adverse events included hypertension, diarrhea, nausea, headache, and nasopharyngitis.
Results from additional fostamatinib trials (OSKIRA-2 and OSKIRA-3) are expected in the second quarter of 2013.
Source: AstraZeneca; April 5, 2013.