Afimetoran Achieves SRI-4 End Point in Phase 2 Lupus Trial

What was Afimetoran’s phase 2 trial design and primary SRI-4 results in SLE?

Beeline Medicines reported positive topline results from a global phase 2 trial of afimetoran in systemic lupus erythematosus (SLE), announced September 9, 2026.^¹ All 2 afimetoran dose groups showed higher SLE Responder Index-4 (SRI-4) response rates at week 48 compared with placebo, meeting the trial's primary endpoint (P <.001 for each dose versus placebo).^¹ The company reported no new safety signals and said it plans to advance afimetoran into pivotal development for both systemic and cutaneous lupus erythematosus.^¹

Afimetoran is an investigational, oral, once-daily inhibitor of Toll-like receptors 7 and 8 (TLR7/TLR8), targets implicated in lupus pathogenesis through innate immune and B-cell signaling.^¹ Human genetics directly implicate TLR7 as a disease driver in lupus, while TLR8 biology contributes to pro-inflammatory cytokine production, according to Beeline Medicines.^¹ The molecule originated at Bristol Myers Squibb and was licensed to Beeline Medicines in July 2025; it previously received FDA Fast Track designation for SLE in May 2025 after showing exploratory efficacy in a phase 1b cutaneous lupus erythematosus study.^¹

The phase 2 trial (NCT04895696) is a global, double-blind, randomized, dose-ranging, placebo-controlled study evaluating afimetoran in 248 adults with active SLE.^¹ Enrolled patients were 18 to 70 years old with active moderate-to-severe disease despite background treatment.^¹ Participants were randomized 1:1:1:1 to once-daily oral afimetoran at one of three dose levels or placebo through week 48, alongside protocol-permitted standard-of-care medications, including corticosteroids with a mandatory taper.^¹

The primary endpoint was SRI-4 response at week 48.^¹ All 3 afimetoran dose groups achieved higher SRI-4 response rates than placebo, with P<.001 for each dose comparison, according to Beeline Medicines.^¹ The company did not disclose dose-specific response rates or exact P values beyond the reported threshold in its topline announcement.^¹

Beeline Medicines said the dose-ranging design was intended to characterize a dose-response relationship ahead of pivotal development.^¹

What were Afimetoran secondary endpoints and safety in SLE phase 2 trial?

Secondary endpoints, which assessed low disease activity, skin and joint manifestations, corticosteroid reduction, physician global assessment, and quality of life, showed improvements consistent with the primary result, according to the company.^¹ Beeline Medicines did not report specific secondary endpoint data, such as BICLA response or corticosteroid-tapering success rates, in its topline release.^¹

Safety and tolerability were generally consistent with prior phase 1 experience, and no new safety signals were observed, the company said.^¹ Specific adverse event (AE) rates, serious AEs, and discontinuation data were not disclosed in the topline announcement.^¹ Beeline Medicines said full results will inform its plans to advance afimetoran into pivotal development for systemic and cutaneous lupus erythematosus.^¹

The phase 2 SLE results mark the first randomized efficacy readout for afimetoran, following earlier phase 1b exploratory data in cutaneous lupus erythematosus.^¹

Saqib Islam, Chief Executive Officer of Beeline Medicines, said, “Too many people with systemic lupus continue to cycle through therapies that do not adequately control their disease, leaving them with diminished quality of life and vulnerable to debilitating long-term complications.”^¹

Nathalie Franchimont, MD, PhD, Chief Medical Officer of Beeline Medicines, added, “For people living with lupus, there is a significant need for effective, well-tolerated therapies that fit into everyday life.”^¹

Beeline Medicines licensed afimetoran from Bristol Myers Squibb in July 2025 and holds FDA Fast Track designation for the drug in SLE.^¹ The company plans to advance afimetoran into pivotal development for both systemic and cutaneous lupus erythematosus, without specifying a phase 3 timeline.^¹

References

1. Beeline Medicines. Beeline Medicines announces positive topline results from global phase 2 study of afimetoran in systemic lupus erythematosus. Published September 9, 2026. Accessed September 9, 2026. https://beelinemedicines.com/press-releases/beeline-medicines-announces-positive-topline-results-from-global-phase-2-study-of-afimetoran-in-systemic-lupus-erythematosus/

2. ClinicalTrials.gov. Phase 2 study of afimetoran in systemic lupus erythematosus. Identifier: NCT04895696. Accessed September 9, 2026. https://clinicaltrials.gov/study/NCT04895696