Alumis LUMUS Trial Misses Primary Endpoint in Overall SLE Population; Prespecified IFNGS-High Subgroup Shows Robust Response, Phase 3 Path Announced

Alumis Inc. (Nasdaq: ALMS) reported topline results from its Phase 2b LUMUS trial on Sept. 1, 2026: envudeucitinib did not meet the primary BICLA endpoint or key secondary endpoints — CLASI-50, SRI-4, and LLDAS — in the overall 408-patient population at Week 48. The stock closed at $21.81, down $0.57, or -2.55%, on the session.

The LUMUS trial was a randomized, double-blind, placebo-controlled study; patients received envudeucitinib or placebo for 48 weeks, per the company's Sept. 1, 2026 news release on GlobeNewswire. IFNGS-high patients — described in that release as representing the majority of moderate-to-severe SLE cases — were unexpectedly under-represented in the enrolled population, which the company says compressed response rates across the full 408-patient group. In the prespecified IFNGS-high subgroup, envudeucitinib improved on the BICLA primary endpoint and all three key secondary endpoints: CLASI-50, SRI-4, and LLDAS, per the same release. Alumis announced plans to engage regulators to discuss Phase 3 development focused on the IFNGS-high population, per reporting by Investing.com cited in the research brief.

Pharmacodynamic data from patients confirmed dose-dependent interferon-pathway target engagement, with maximal suppression recorded at the highest dose tested, 40mg twice-daily, per the Sept. 1 GlobeNewswire release.

"Although envudeucitinib did not meet its primary objective in the overall trial population, the magnitude of effect observed in the prespecified IFNGS-high subgroup is highly compelling in a disease with no targeted oral therapies currently available," said Dr. Jörn Drappa, Chief Medical Officer of Alumis.

The safety read from LUMUS was clean: envudeucitinib was well tolerated with no new safety signals identified across the trial, per the Sept. 1 release.

The company has not disclosed the size of the IFNGS-high cohort within the 408-patient LUMUS population. That figure was not available in the Sept. 1 release at the time of publication.

On the psoriasis program: positive Phase 3 ONWARD results for envudeucitinib in moderate-to-severe plaque psoriasis were announced in June 2026 at the AAD meeting, and Alumis says it remains on track to submit an NDA in that indication in 4Q 2026, per the Sept. 1 GlobeNewswire release.

ALMS opened at $22.29 on Sept. 1 and traded on volume reported as 0 at open, per Yahoo Finance. The session close of $21.81 reflected a -2.55% move. The company's market cap was reported at $2.91 billion per Robinhood as-of data from the trading session. Cash position and shares outstanding were not available from Q2 2026 filings at the time of publication.

The conference call and webcast were scheduled for Sept. 1 at 8:30 a.m. EDT. Upcoming milestones disclosed in the Sept. 1 release: regulatory feedback on the proposed Phase 3 IFNGS-high design, and the NDA submission for psoriasis in the fourth quarter of 2026.