Equillium Reveals Phase 3 EQUATOR Study Results for Itolizumab in Treating Acute Graft-Versus-Host Disease

Equillium, Inc., a biotechnology firm focused on developing treatments for autoimmune and inflammatory disorders, has revealed the results of its Phase 3 EQUATOR study on itolizumab for treating acute graft-versus-host disease (aGVHD). This study aims to assess the effectiveness and safety of itolizumab, a first-in-class monoclonal antibody, in patients suffering from this condition.

The EQUATOR study involved 158 adult and adolescent participants diagnosed with Grade III-IV aGVHD or Grade II aGVHD with lower gastrointestinal tract involvement. The trial was designed as a randomized, double-blind, placebo-controlled study to evaluate the efficacy of intravenously administered itolizumab in combination with high-dose corticosteroids. Participants were split into two groups, with one receiving the drug and the other receiving a placebo, alongside the standard treatment of corticosteroids.

The primary objective of the study was to measure the complete response (CR) rate at Day 29, while secondary objectives included overall response rate (ORR) at Day 29, durable CR from Day 29 through Day 99, and other long-term outcomes like failure-free survival and overall survival.

The study found no significant difference in the primary endpoint of CR or the key secondary endpoint of ORR at Day 29 between those treated with itolizumab and those receiving the placebo. However, itolizumab showed statistically significant improvements in several longer-term outcomes, including CR at Day 99 and duration of CR, indicating a compelling clinical benefit in these areas. Itolizumab was also found to have a favorable safety profile, with no increased risk of infections or sepsis, which are common complications in aGVHD.

Bruce Steel, Equillium's CEO, expressed optimism about the results, particularly the longer-term outcomes. He noted that there are currently no approved therapies for first-line treatment of aGVHD, a condition with a high one-year mortality rate. As a result, Equillium has filed for Breakthrough Therapy designation and is planning discussions with the FDA about potential Accelerated Approval pathways. Feedback from the FDA is anticipated by May 2025, with a possible submission for a biologics license application in the first half of 2026.

Dr. John Koreth, a medical expert at Harvard Medical School, emphasized the importance of the study’s longer-term outcomes, noting the lack of effective first-line therapies for aGVHD. The ability of itolizumab to demonstrate significant improvement in pre-specified endpoints compared to standard care is considered clinically meaningful.

The EQUATOR study's safety profile aligned with previous studies of itolizumab, reinforcing its safety and tolerability. The trial continues, with patients in the follow-up phase, and an independent committee regularly reviewing the study's safety data.

Itolizumab works by targeting the CD6-ALCAM signaling pathway, which modulates T-cell activity involved in various immuno-inflammatory diseases. Equillium is utilizing its expertise in immunobiology to develop this novel therapeutic, which has already received Orphan Drug and Fast Track designations for aGVHD treatment.

This latest development in itolizumab’s clinical evaluation underscores Equillium's commitment to addressing high unmet medical needs in autoimmune and inflammatory disorders through innovative treatments.