Equillium, Inc. announced positive topline data from the Type B portion of the Phase 1b EQUALISE study evaluating itolizumab in lupus nephritis patients. The data suggests high complete and partial response rates with rapid and deep reduction in urine protein creatinine ratio (UPCR) when itolizumab was added to mycophenolate mofetil/mycophenolic acid (MMF/MPA) and corticosteroids. The topline data delivered to partner, Ono Pharmaceutical, represents the first of two data set triggers leading to their decision as to whether to exercise their option to acquire itolizumab, which is expected in the second half of 2024. A total of 17 subjects were enrolled in the study, with 16 subjects analyzed as completing through Week 36 (12 weeks following the final dose, or their end of study (EOS) visit). Based on published guidelines for the management of lupus nephritis from the European League Against Rheumatism (EULAR) and European Renal Association-European Dialysis and Transplant Association (ERA-EDTA), clinical activity assessments in this study are focused on the change in UPCR from baseline; proportion of apLN subjects with a complete response (CR), defined as 50% or greater reduction in UPCR and less than 0.5-0.7 g/g; and proportion of subjects achieving a partial response (PR), defined as 50% or greater reduction in UPCR. Key topline data from the Type B portion of the EQUALISE study in lupus nephritis: Subjects were highly proteinuric: baseline mean UPCR of 4.9 g/g. Percent reduction from baseline in median spot UPCR is ~73%. Best clinical response observed by week 36 or their EOS visit: 6 of 16 (37.5%) subjects achieved CR (UPCR < 0.7 g/g) Additional 7 of 16 (43.8%) subjects achieved PR (UPCR > 50% reduction) There was a greater overall response rate (ORR) achieved in patients receiving itolizumab by 12 and 28 weeks than expected compared to the ORR in patients receiving standard of care alone using data generated from the Accelerating Medicines Partnership® (AMP) Lupus Network. Results are comparable to those observed in the Phase 3 AURORA1 study of voclosporin (ORR 70% at 6 and 12 months in active treatment). Consistent with the decline in UPCR overtime, subjects were able to taper their systemic corticosteroids over the course of the study with >80% reduction by Week 24. Itolizumab induced consistent pharmacodynamic responses in patients reducing the levels of cell surface CD6 on T cells, which is known to reduce T cell activity.
Itolizumab treatment (over 6 months) was also associated with reductions in absolute lymphocyte counts (ALC), another known pharmacodynamic effect. As noted in other studies of drugs whose mechanism leads to reductions in ALC, such as the S1P modulators, the reduction in ALC observed here was not associated with increased rates of infection or other adverse clinical signals. The majority of TEAEs were assessed as mild (Grade 1) or moderate (Grade 2) in severity, with the two most common TEAEs being lymphopenia and peripheral edema. Two subjects had at least one serious adverse event, none of which were related to study treatment. SLE is an autoimmune disease in which the immune system attacks its own tissues, causing widespread inflammation and tissue damage in the affected organs. It can affect the joints, skin, brain, lungs, kidneys, and blood vessels. LN is a serious complication of SLE, occurring in approximately 30% ? 60% of individuals with SLE. LN involves the body?s own immune system attacking the kidneys, causing inflammation and significantly reducing kidney function over time. LN is associated with an increase in mortality compared with the general population and may lead to end-stage renal disease. The EQUALISE study was a two-part Phase 1b open-label proof-of-concept study of itolizumab in patients with SLE and LN. The Type A portion of the study was a multiple ascending-dose clinical study evaluating the safety and tolerability of subcutaneous delivery of itolizumab over a two-week treatment period in 35 patients with SLE. The Type B portion of the study evaluated the safety, tolerability and clinical activity of subcutaneous delivery of itolizumab dosed at 1.6 mg/kg every two weeks over a 24-week treatment period, with follow up out to 36 weeks, in patients with active proliferative LN. Patients in the Type B portion of the study must have presented with greater than 1 gram of proteinuria and had a recent kidney biopsy showing ISN/RPS class III or IV apLN to be eligible for the study. Consistent with standard of care, patients on study also received 2-3 g/day of mycophenolate mofetil/mycophenolic acid (MMF/MPA), and patients may have received pulse systemic corticosteroids that were rapidly tapered. Itolizumab is a clinical-stage, first-in-class anti-CD6 monoclonal antibody that selectively targets the CD6-ALCAM signaling pathway to selectively downregulate pathogenic T effector cells while preserving T regulatory cells critical for maintaining a balanced immune response. This pathway plays a central role in modulating the activity and trafficking of T cells that drive a number of immuno-inflammatory diseases.