Zenas asks FDA to approve IgG4-RD treatment obexelimab
Experimental injection therapy can be self-administered
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Zenas Biopharma has submitted an application to the U.S. Food and Drug Administration (FDA) seeking approval of its experimental injection therapy, obexelimab, for immunoglobulin G4-related disease (IgG4-RD).
“Our obexelimab [biologics license application] submission brings us one step closer to our goal of delivering this meaningful treatment option to patients living with IgG4-RD,” Lisa von Moltke, MD, head of research and development and chief medical officer of Zenas, said in a company press release.
The company expects to submit a similar application to the European Medicines Agency later this year seeking approval of obexelimab in the European Union.
IgG4-RD is marked by abnormal clumps of immune cells — mostly plasmablasts, mature forms of immune B-cells, producing the IgG4 antibody. These clumps form in tissues, causing inflammation and scarring that can drive a wide array of IgG4-RD symptoms.
Obexelimab works to suppress B-cell activity by blocking the activity of two proteins involved in the cells’ immune activity, CD19 and FCGR2B. The therapy, which is given by subcutaneous (under-the-skin) injection that can be self-administered, is designed to reduce activity of several B-cell populations, including plasmablasts, without killing the cells.
Promising results from clinical trials
Zenas’ FDA application is based mainly on data from the Phase 3 INDIGO clinical trial (NCT05662241), which tested the therapy against a placebo in roughly 200 adults with active IgG4-RD who needed treatment with standard glucocorticoids.
Results from INDIGO showed obexelimab significantly reduced the risk of disease flares, by 56%, after one year, meeting the study’s main goal. Obexelimab also bested the placebo on several key secondary goals, including time to first disease flare requiring rescue therapy, total number of flares requiring rescue therapy, proportion of patients achieving complete disease remission, and cumulative use of glucocorticoid rescue therapy.
Adverse events (side effects and other safety issues) were reported in almost all patients in both the obexelimab and placebo groups, though obexelimab was associated with lower rates of severe adverse events (11.3% vs. 23.7%) and serious adverse events (10.3% vs. 18.6%).
Infections occurred in just over half of patients in both groups (53.6% in obexelimab and 62.9% in placebo). Generally similar rates of events were also seen for injection-site reactions (3.5% vs. 2.3%) and allergic reactions (16.5% vs. 11.3%). One trial participant, on the placebo, died during the study.
“Based on the significant clinical activity and the favorable safety and tolerability profile observed in the INDIGO study, we believe obexelimab may have an important role as a first line therapy in the long-term management of IgG4-RD,” von Moltke said.
