AnaptysBio has set the stage for negotiations over its rare skin disease drug candidate, delivering phase 3 data that suggest the asset can challenge Boehringer Ingelheim in generalized pustular psoriasis (GPP).
San Diego-based Anaptys abandoned plans to bring imsidolimab to the U.S. market itself after seeing the drug candidate fail a phase 2 trial in hidradenitis suppurativa last year. With the phase 3 GPP study already underway, Anaptys opted to continue in that indication but out-license the asset before a potential FDA approval.
Now, Anaptys has published top-line data from the late-stage trial. The trial randomized 45 patients to receive a single intravenous dose of anti-IL-36R antibody imsidolimab or placebo. Four weeks later, 53.3% of people on imsidolimab had a score of clear or almost clear on a physician assessment scale.
The improvement over the placebo response rate, 13.3%, was big enough for the study to hit its primary endpoint. Imsidolimab will face a tougher rival than placebo if it comes to market. Boehringer won FDA approval for a rival IL-36R drug, Spevigo, last year.
Spevigo came to market on the strength of a clinical trial that assessed its effect on pustulation, one of the disease attributes that makes up the physician scale used in the Anaptys study. Boehringer showed that 54% of patients who received the antibody had a score of clear on the pustulation, compared to 6% of their counterparts on placebo, one week after treatment.
Boehringer used the overall physician scale as a secondary endpoint, showing that 43% of participants on Spevigo were clear or almost clear one week after treatment. The rate for the placebo arm was 11%. In an exploratory endpoint, Boehringer linked Spevigo to a 66% rate of clear or almost clear in Week 4.
It is unclear from the cross-trial comparison, an unreliable way of evaluating the relative merits of drugs, if either product has the upper hand. But Anaptys is confident of what it’s produced to date, with CEO Daniel Faga calling the data set “compelling and competitive” in a statement today.
The biotech plans to file for FDA approval in the third quarter of 2024 and out-license the drug candidate next year. Shares in Anaptys briefly climbed 17% to $22.51 in premarket trading Monday in the wake of the readout before dropping down to $20.54.