Zenas shares plunge on weaker-than-expected data for immune disorder drug

By Sahil Pandey

Jan 5 (Reuters) – Zenas BioPharma said on Monday its experimental drug cut the risk of flare-ups of a rare autoimmune disease in a late-stage study, but its shares fell 57% as the drug’s efficacy fell short of expectations.

The drugmaker was testing its therapy, obexelimabin, in patients with immunoglobulin G4-related disease, in which an overactive immune system can inflame and scar organs including the pancreas, liver and kidneys.

The company said patients who received the therapy saw a 56% reduction in the risk of flare-ups, or a hazard ratio of 0.44, compared to placebo over a 52-week period, meeting the main goal of the study.

But Wedbush Securities analyst Martin Fan said the hazard ratio came below expectations of 0.30 or lower.

Last year, Amgen’s Uplizna became the first treatment approved by the U.S. Food and Drug Administration to treat the condition. Uplizna had showed a 87% reduction in the risk of flares-ups in a late-stage study.

“I think I’ll go back and point once again, to the almost 60% risk reduction, as opposed to comparing to the Uplizna study,” Zenas CEO Lonnie Moulder said in a call with analysts.

In Zenas’ trial, 194 patients globally were administered obexelimab as a weekly under-the-skin injection. The therapy was well tolerated, with no new safety concerns reported, Zenas said.

The company plans to seek approval from U.S. and European regulators this year.

(Reporting by Sahil Pandey and Sneha S K in Bengaluru; Editing by Sahal Muhammed)