Rigel falls on Phase IIb data for RA compound

Rigel Pharmaceuticals Inc. (NASDAQ:RIGL) fell $2.92 (35%) to $5.51 on Thursday after partner AstraZeneca plc (LSE:AZN; NYSE:AZN) said fostamatinib disodium monotherapy was inferior to active comparator Humira adalimumab in the Phase IIb OSKIRA-4 trial to treat rheumatoid arthritis. Specifically, all three dose regimens of oral fostamatinib missed the co-primary endpoint of non-inferiority to subcutaneous Humira in improving Disease Activity Score using 28 joint counts (DAS28) scores from baseline to week 24. The two highest-dose regimens of fostamatinib did meet the co-primary endpoint of superiority over placebo in improving DAS28 score from baseline to week six. The trial enrolled 280 RA patients who had never received a DMARD, were DMARD intolerant or who had an inadequate response to DMARDs. ...