Alumis shares fell 56.76%, after reaching an intraday decline of 57.86%, following the failure of its Phase 2b LUMUS trial of envudeucitinib to meet primary or secondary endpoints in the overall population of patients with moderate-to-severe systemic lupus erythematosus. The 408-participant study measured disease-activity improvement at 48 weeks using the British Isles Lupus Assessment Group-based Composite Lupus Assessment. A prespecified subgroup with high interferon gene signatures, or IFNGS-high, showed significant improvement on the primary and key secondary measures, including SLE Responder Index 4, CLASI-50 and Lupus Low Disease Activity State, but the group was underrepresented in the trial. Alumis said the drug was well tolerated, with no new safety signals, while pharmacodynamic data showed dose-dependent suppression of interferon signaling at doses up to 40 milligrams twice daily. The company plans to discuss a Phase 3 lupus program focused on IFNGS-high patients and remains on track to file a New Drug Application for envudeucitinib in moderate-to-severe plaque psoriasis in the fourth quarter of 2026, supported by positive Phase 3 ONWARD data.