AstraZeneca Announces Results from OSKIRA-1 Phase 3 Study of Fostamatinib in Rheumatoid Arthritis

AstraZeneca

today announced top-line results of OSKIRA-1, a Phase 3 study to assess the efficacy and safety of fostamatinib, the first oral spleen tyrosine kinase (SYK) inhibitor in development for rheumatoid arthritis (RA).  OSKIRA-1 had two primary endpoints: assessing signs and symptoms of RA as measured by ACR20 response rates, and an X-ray endpoint known as mTSS (modified Total Sharp Score). In the OSKIRA-1 study, fostamatinib achieved a statistically significant improvement in ACR20 response rate at 24 weeks in both the 100 mg twice daily group and the group that received 100 mg twice daily for four weeks followed by 150 mg once daily (49%, p<0.001 and 44%, p=0.006 respectively) compared to placebo (34%). Fostamatinib did not demonstrate a statistically significant difference in mTSS compared to placebo at 24 weeks for either dose (p=0.252 and p=0.170, respectively). The safety and tolerability findings for fostamatinib observed in the OSKIRA-1 study were generally consistent with those previously reported for the TASKi Phase 2 program. The most commonly reported adverse events were typical of those seen in earlier studies, including hypertension, diarrhea, nausea, headache and nasopharyngitis (common cold). Briggs Morrison, MD, executive vice president of Global Medicines Development