Envudeucitinib misses Phase IIb lupus endpoints, subgroup signal keeps program alive

The Phase IIb LUMUS trial of envudeucitinib in systemic lupus erythematosus (SLE) failed to meet its primary and secondary endpoints in the overall patient population, Alumis Inc. (Nasdaq: ALMS) reported on September 1. The miss affects Alumis' multi-indication ambitions for the oral TYK2 inhibitor, though the company said responses in a prespecified interferon gene signature-high (IFNGS-high) subgroup support advancing to Phase III in an enriched population.

The 408-patient LUMUS trial evaluated three doses of envudeucitinib against placebo over 48 weeks in adults with moderately-to-severely active, autoantibody-positive SLE. The primary endpoint was British Isles Lupus Assessment Group-based Composite Lupus Assessment (BICLA) response at Week 48. Neither BICLA nor key secondary endpoints — including CLASI-50, SRI-4, and Lupus Low Disease Activity State — were met in the overall population. Alumis attributed the failure partly to an unexpected under-representation of IFNGS-high patients in the enrolled cohort. Because this subgroup typically shows lower placebo response rates and greater sensitivity to interferon pathway-targeted agents, its dilution in the overall population reduced detectable treatment effects. In IFNGS-high patients — who Alumis said represent the majority of moderate-to-severe SLE cases — robust responses were observed across BICLA and the key secondary measures. No specific response rates were disclosed. Pharmacodynamic data confirmed dose-dependent interferon-pathway suppression, with maximal effect at the highest dose of 40 mg twice daily.

Envudeucitinib is a highly selective oral allosteric inhibitor of tyrosine kinase 2 (TYK2) that blocks signaling downstream of the type I interferon, IL-23, and IL-12 receptors.

The SLE result arrives as Alumis prepares to submit an NDA for envudeucitinib in moderate-to-severe plaque psoriasis in Q4 2026, following positive Phase III ONWARD1 and ONWARD2 data reported in January 2026 and long-term ONWARD3 extension data in August 2026 showing 54% of patients achieving complete skin clearance (PASI 100) after 48 weeks of continuous treatment. The psoriasis program remains the company's near-term commercial anchor.

The SLE setback narrows but does not close the oral TYK2 path in lupus. No targeted oral therapy is currently approved for SLE; the two approved targeted biologics — AstraZeneca's Saphnelo (anifrolumab), a type I interferon receptor antagonist, and GSK's Benlysta (belimumab), a BLyS inhibitor — are both injectable. Alumis said it plans to engage regulators to discuss a Phase III design enriched for IFNGS-high patients. Whether regulators accept a biomarker-selected trial based on a subgroup from a failed Phase IIb — without a prospectively powered Phase IIb in that subgroup — will be a central question for that discussion. The company also cited cutaneous lupus erythematosus and Sjögren's disease as potential indications within the type I interferon-driven disease space.

In the psoriasis arena, envudeucitinib faces direct oral competition from Bristol Myers Squibb's Sotyktu (deucravacitinib), the first approved TYK2 inhibitor, and Johnson & Johnson's Icotyde (icotrokinra), an oral IL-23 receptor antagonist approved in March 2026. Takeda's zasocitinib, another oral allosteric TYK2 inhibitor that demonstrated superiority over deucravacitinib in a head-to-head Phase III trial, is also targeting an NDA filing. Alumis reported PASI 90 rates of approximately 65% at Week 24 on average across its two Phase III psoriasis trials, with the twice-daily dosing schedule a potential disadvantage against once-daily competitors.

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