Positive Phase 3 GEMINI-2 Results for Imsidolimab in Treating GPP

AnaptysBio, a clinical-stage biotech firm, has reported encouraging findings from its Phase 3 GEMINI-1 and GEMINI-2 trials for imsidolimab, a treatment for generalized pustular psoriasis (GPP), a severe and potentially life-threatening condition. In the GEMINI-1 trial, patients were given either a single 750mg or 300mg intravenous dose of imsidolimab or a placebo. By Week 4, 53% of those on the higher dose and the same percentage on the lower dose achieved clear or almost clear skin, compared to 13% on the placebo.
In the subsequent GEMINI-2 trial, sixteen patients who responded to the initial treatment were re-randomized to receive either monthly subcutaneous imsidolimab or a placebo for maintenance. Over a period extending up to 92 weeks, all eight patients on imsidolimab maintained their skin condition, while among those on placebo, only 25% maintained clear skin, and 63% experienced a flare-up.
The drug demonstrated a favorable safety profile, with no serious adverse events related to treatment and a low incidence of infections. There were no reports of Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) or Guillain-Barre syndrome (GBS), and the overall occurrence of anti-drug antibodies was minimal.
AnaptysBio's CEO, Daniel Faga, highlighted the company's commitment to developing effective antibodies, noting that imsidolimab's rapid and sustained effect on GPP was achieved with just a single IV dose, followed by monthly subcutaneous doses. The company plans to submit the trial data to a medical conference in the second half of 2024 and intends to out-license imsidolimab, with a potential biologics license application (BLA) to the FDA pending a successful out-licensing agreement.
The GEMINI-1 trial was a four-week, randomized, double-blind, placebo-controlled study involving 45 patients across various global regions. The GEMINI-2 trial aimed to assess the efficacy of imsidolimab for maintaining response and preventing flares with monthly dosing, with 42 patients re-randomized for the study.
Imsidolimab is a humanized IgG4 antibody that targets the interleukin-36-receptor (IL-36R) and is being developed to treat GPP. GPP is characterized by sudden, painful pustules over large skin areas, accompanied by redness, itching, and other systemic symptoms. AnaptysBio is also developing other immunology therapeutics and has a portfolio of immune cell modulators and cytokine antagonists in various stages of development and testing.