Alumis stock fell about 56% on Tuesday after the company said its Phase 2b LUMUS trial of envudeucitinib failed to meet its primary and secondary endpoints in patients with moderate-to-severe systemic lupus erythematosus (SLE).

The stock was down as much as 57.86% during the session. Alumis Inc. trades under the ticker ALMS.

The trial enrolled 408 patients and assessed disease activity using the British Isles Lupus Assessment Group-based Composite Lupus Assessment, or BICLA, at Week 48. That primary endpoint was not met, and secondary endpoints in the overall population also missed.

The company did identify one notable subgroup result. A prespecified group of patients with high interferon gene signatures, or IFNGS-high, showed strong clinical responses on both the primary endpoint and key secondary measures.

🚨 ALUMIS $ALMS JUST COLLAPSED 55% AFTER ITS LUPUS CLINICAL TRIAL FAILED $ALMS erased $1.5B in valuation today after its 408-patient Phase 2b LUMUS trial missed its primary endpoint despite being described as “potentially pivotal.” The drug showed promise in patients with… pic.twitter.com/Bpfpv2gKMQ — Limitless Finance (@trylimitlessfin) September 1, 2026

🚨 ALUMIS $ALMS JUST COLLAPSED 55% AFTER ITS LUPUS CLINICAL TRIAL FAILED $ALMS erased $1.5B in valuation today after its 408-patient Phase 2b LUMUS trial missed its primary endpoint despite being described as “potentially pivotal.” The drug showed promise in patients with… pic.twitter.com/Bpfpv2gKMQ

— Limitless Finance (@trylimitlessfin) September 1, 2026

Alumis said IFNGS-high patients make up the majority of moderate-to-severe SLE cases, but this subgroup was unexpectedly under-represented in the trial, which weighed on the overall readout.

The company also said envudeucitinib was well tolerated throughout the study and that no new safety signals were observed. Pharmacodynamic data showed robust dose-dependent engagement of the interferon pathway, with the highest dose of 40 mg twice daily producing maximal suppression.

What Alumis plans next

Alumis said it plans to discuss with regulators the design of a Phase 3 study focused specifically on the IFNGS-high lupus population. That next step matters because lupus remains a difficult area for drug development, and the company emphasized that there are currently no targeted oral therapies for SLE.

Its psoriasis program remains on track. Alumis said it still expects to submit a New Drug Application for envudeucitinib in moderate-to-severe plaque psoriasis in Q4 2026, following positive data from its Phase 3 ONWARD program in plaque psoriasis. That means the lupus setback does not change the broader development timetable for the drug in another immune-mediated disease area.

The bigger picture for Alumis

Envudeucitinib is an oral allosteric inhibitor of tyrosine kinase 2, or TYK2. It targets immune pathways driven by IL-23, IL-17, and Type I interferon.

Because the drug uses the same mechanism across lupus and psoriasis, the IFNGS-high subgroup data continues to draw attention from investors and analysts tracking the company’s pipeline.

Before Tuesday’s selloff, Alumis had a market capitalization of about $2.99 billion. The stock had risen more than 123% year to date heading into the news. Average daily trading volume was around 1.29 million shares, and the technical sentiment signal had been rated Hold before the announcement.