Equillium (EQ) Study Result summary

Study design and patient population

• Phase III EQUATOR study was a randomized, double-blind, placebo-controlled trial evaluating itolizumab in 158 patients with first-line acute GVHD, including those with severe disease (grade 3/4 or grade 2 with lower GI involvement).

• Patients received itolizumab or placebo plus high-dose corticosteroids within three days, dosed every other week for up to three months, with follow-up to Day 365.

• Median age was 59 years (range 18–75), with balanced sex and regional distribution; 92% had lower GI involvement and 55.7% were Minnesota High Risk.

• Study included 150–158 patients, with participation from 9 of the top 10 transplant centers and nearly 40% of patients from the U.S.

Efficacy outcomes

• Primary endpoint (CR at Day 29) was not met: CR rates were 43% for itolizumab vs. 48% for placebo (not statistically significant).

• Durable CR at Day 99 was 29% for itolizumab vs. 16% for placebo; among Day 29 CRs, 67.6% (itolizumab) vs. 34.2% (placebo) maintained CR (p=0.005).

• CR at Day 99 achieved statistical significance: 44.9% for itolizumab vs. 28.6% for placebo (p=0.035).

• Median duration of CR was 336 days for itolizumab vs. 72 for placebo (p=0.017); failure-free survival was 154 vs. 70 days (p=0.043).

• Overall survival at 1 year trended favorably for itolizumab (66.7% vs. 49.6%), though not statistically significant.

Safety and tolerability

• Itolizumab showed a favorable safety profile, with no increase in infection or sepsis risk compared to placebo.

• TEAEs occurred in 98.7% (itolizumab) and 96.1% (placebo); serious TEAEs in 57.7% (itolizumab) and 61.0% (placebo).

• TEAEs leading to death: 23.1% (itolizumab) vs. 32.5% (placebo); none were treatment-related.

• AE-related discontinuations were infrequent and mostly due to infusion reactions; TEAEs leading to discontinuation were higher with itolizumab (12.8% vs. 3.9%).

• No significant difference in steroid tapering, primary disease relapse, or chronic GVHD rates between arms.