Equillium, Inc. announced that the Phase 1b EQUIP study of itolizumab in patients with uncontrolled asthma met its primary objective of safety and tolerability and demonstrated on-target peak and sustained reduction of CD6 at Day 85 (one month following last dose). Itolizumab is a first-in-class anti-CD6 monoclonal antibody that targets the CD6-ALCAM signaling pathway to selectively inhibit pathogenic T effector cells. The data, collected from a total of 18 patients, shows that subcutaneous delivery of itolizumab was generally safe and well tolerated at 0.8 mg/kg (Cohort 1, n=7 treatment and n=2 placebo) and 1.6 mg/kg (Cohort 2, n=7 treatment and n=2 placebo).

All subjects (0.8 mg/kg, 1.6 mg/kg, and placebo) reported at least one adverse event. Most subjects (83%) had adverse events that were mild or moderate in severity. The most reported adverse events for subjects treated across all doses with itolizumab were transient lymphopenia (79%), a known drug effect, and injection site reaction or rash (57%; all mild in severity).

There was one SAE (peripheral artery thrombosis) reported in the 1.6 mg/kg dosing cohort, which resolved without sequelae. Pharmacodynamic data demonstrated significant and comparable reductions in cell surface CD6 at both dose levels of 0.8 and 1.6 mg/kg compared to placebo. The loss of cell surface CD6 was rapid, observed on the first evaluation at Day 8, and durable with levels remaining suppressed through Day 85, 28 days after the last dose (Day 57).

The reductions in CD6 were similar to those observed in the EQUALISE study where subcutaneous dosing of systemic lupus erythematosus patients showed maximal loss of CD6 between 0.8 and 1.6mg/kg. The study was completed after Cohort 2 as no further pharmacodynamic effects were anticipated at higher doses. Asthma control questionnaire (ACQ-6) scores, used to measure the adequacy and change in asthma control resulting from treatment, improved (numerically declined) from baseline across all treated subjects from 2.18 to 1.34 at Day 85, the end of the study.

FEV-1, or forced expiratory volume, a measure of lung function, improved in Cohort 1, declined in Cohort 2, and was variable at different time points. Overall, there were 4 subjects with a total of 5 asthma exacerbations (defined as requiring systemic corticosteroids), including one patient in the treatment arm of Cohort 1 and 3 patients in the treatment arm of Cohort 2.