Anaptys Reports Positive Top-Line Phase 3 Results of Generalized Pustular Psoriasis Candidate

Rare Daily Staff

AnaptysBio reported results from its global phase 3 GEMINI-1 trial evaluating its experimental therapy imsidolimab in patients with generalized pustular psoriasis flares, which showed it met is primary endpoint and demonstrated a favorable safety profile.

The study population achieved rapid clearance of pustulation, erythema, and scaling through Week 4 after a single dose of imsidolimab.

Generalized pustular psoriasis (GPP) is a rare, chronic, systemic autoinflammatory disease that is potentially life-threatening, if left untreated. During a GPP flare, individuals experience the sudden eruption of painful pustules. These pustules appear over large areas of the skin, accompanied by redness, severe itchiness, and dry, cracked, or scaly skin. People with GPP may also experience more general symptoms such as fever, headache, extreme tiredness, or a burning sensation on the skin.

Imsidolimab is an IgG4 antibody that inhibits the function of the interleukin-36 receptor (IL-36R), a signaling pathway within the immune system shown to be involved in the pathogenesis of inflammatory diseases, including GPP. The registration-enabling GEMINI-1 trial in GPP, which recruited 45 patients, is the first randomized, double-blind, placebo-controlled trial to use the composite endpoint of Generalized Pustular Psoriasis Physician Global Assessment (GPPPGA) at Week 4 as its primary assessment. The GPPPGA assessment, a comprehensive characterization of disease severity, required satisfying an overall clinical response score of 0/1 (clear or almost clear) collectively across each GPP disease attribute, including pustulation, erythema, and scaling.

“GPP is an unpredictable and potentially life-threatening skin disease with systemic symptoms,” said Professor Hervé Bachelez, Hôpital Saint-Louis, Paris, one of the world’s leading experts on GPP. “Achieving positive top-line results utilizing the GPPPGA composite endpoint in this well conducted, randomized controlled, global trial, along with a compelling safety profile, represents the potential for a single dose of imsidolimab to predictably provide relief for patients living with this burdensome disease.”

Some 53.3 percent of patients who received a single dose of 750mg IV imsidolimab achieved GPPPGA 0/1 (clear or almost clear) at Week 4 (primary endpoint), compared to 13.3 percent of patients on placebo. Additionally, 66.7 percent of placebo patients exited GEMINI-1 early, crossed-over to GEMINI-2 and were eligible to receive rescue therapy with a single dose of 750 mg IV imsidolimab.

All adverse events reported in imsidolimab-treated patients were mild or moderate and balanced across imsidolimab-treated vs. placebo patients. There were no serious adverse events.

Anaptys plans to present comprehensive data from GEMINI-1 and top-line GEMINI-2 results at a medical meeting in the second half of 2024. The company expects to file a biologics license application with the U.S. Food and Drug Administration by the third quarter of 2024.

“Moving forward, we intend to out-license imsidolimab with this compelling and competitive dataset to bring this therapy to patients living with this highly morbid condition and reallocate the potential proceeds of a transaction to further invest in the broad development of our best-in-class immune cell modulators, including our checkpoint agonists, in autoimmune and inflammatory diseases,” said Daniel Faga, president and CEO of Anaptys.

Photo: Daniel Faga, president and CEO of Anaptys