Sanofi and Regeneron have announced that the investigational IL-33 antibody REGN3500 (SAR440340) met its primary and secondary endpoints in the joint phase II proof-of-concept trial.

The companies are currently studying REGN3500 in respiratory and dermatological diseases where inflammation is thought to play an underlying role. It is being studied in Phase II trials for asthma, chronic obstructive pulmonary disease and atopic dermatitis.

The drug is a is a fully-human monoclonal antibody that inhibits interleukin-33 (IL-33), a protein that is believed to play a key role in type I and type II inflammation.

In a release, the companies noted that in the trial, the greatest improvement was observed in patients with blood eosinophil levels ≥300 cells/microliter. Patients treated with Dupixent (dupilumab) monotherapy did numerically better than REGN3500 across all endpoints, although the trial was not powered to show differences between active treatment arms. The combination of REGN3500 and Dupixent also did not demonstrate increased benefit compared to Dupixent monotherapy in this trial.

The trial results suggest that “REGN3500 may provide an alternative targeted approach for patients suffering from asthma,” said George D. Yancopoulos, president and chief scientific officer at Regeneron. “We look forward to working with Sanofi to advance REGN3500 through our asthma clinical trial program, as well as continuing our ongoing trials in atopic dermatitis and chronic obstructive pulmonary disease.”

Patients with moderate-to-severe asthma often have inadequately controlled, persistent symptoms that may make them suitable for treatment with a biologic therapy.