XBiotech Reports Positive Phase II Results for Anti-IL-1α Monoclonal Antibody in Colorectal Cancer

AUSTIN, Texas, Oct. 19, 2026 /CourierPR/ -- XBiotech, a biotechnology company based in Austin, Texas, has announced positive results from a Phase II clinical trial of its anti-IL-1α monoclonal antibody, XB2001 (Natrunix™, vilamakitug), in patients with refractory metastatic colorectal cancer (mCRC). The trial, funded by the French National Cancer Institute (INCa) and conducted by the Centre Georges-François Leclerc (CGFL) in Dijon, France, met its pre-specified primary efficacy success criterion with 61.3% 12-month overall survival.

The multicenter TASKIN clinical trial evaluated the addition of vilamakitug to standard-of-care trifluridine/tipiracil (TAS-102) with or without bevacizumab. At the 12-month landmark analysis, 49 out of 80 evaluable patients (61.3%) in the vilamakitug experimental arm were alive, surpassing the protocol-defined threshold of 42 or more surviving patients required to establish efficacy. In the control arm (placebo plus standard chemotherapy), 44 out of 79 evaluable patients (55.7%) were alive at 12 months.

The study also reported on the time to strategy failure (TSF), with a 12-month TSF rate of 31.2% in the vilamakitug arm compared to 20.3% in the control arm (log-rank p = 0.17). Progression-Free Survival (PFS) showed median PFS of 5.9 months for the vilamakitug arm versus 5.6 months for the control arm, with a 12-month PFS rate of 25.0% versus 21.0% (log-rank p = 0.42), with survival curves visibly separating after month 7.

Safety and treatment adherence were also assessed, with vilamakitug demonstrating high feasibility in combination with chemotherapy, showing a 96.4% mean compliance rate for trifluridine/tipiracil and only a 1.3% permanent discontinuation rate for vilamakitug/placebo.

An exploratory endpoint analysis revealed a significant survival benefit in patients with right-sided primary tumors (n = 37), a subtype characterized by aggressive tumor biology and high unmet medical need. Vilamakitug demonstrated a statistically significant 62% reduction in the risk of death compared to control (Hazard Ratio [HR] = 0.38; 95% CI: 0.14-0.99; Cox p = 0.047, log-rank p = 0.038) through 12 months. Vilamakitug also achieved a 61% reduction in the risk of treatment strategy failure compared to control (HR = 0.39; 95% CI: 0.18-0.85; Cox p = 0.017, log-rank p = 0.014) through 12 months.