Rigel shares fall as asthma compound fails to meet primary endpoint

Shares of USA-based Rigel Pharmaceuticals (Nasdaq: RIGL) fell 10% to $3.27 in morning trading yesterday after it was revealed that the firm’s potential asthma treatment R343 did not meet its primary endpoint in a key study.

R343, an inhaled SYK inhibitor being evaluated as a potential therapeutic for patients with allergic asthma, did not meet the primary or secondary endpoints in a recently-completed Phase II clinical study. The primary endpoint was the change in pre-bronchodilator FEV1 (a measure of lung function) from baseline to dosing completion at week eight, comparing active doses to placebo. R343 was shown to be relatively safe and well tolerated at both doses. In light of these overall findings, the company said it has decided not to pursue this indication with R343.

Unexpected results