XBiotech recently completed a groundbreaking double-blind, placebo controlled Phase III trial to evaluate Xilonix™ therapy in colorectal cancer patients. The study, which used both innovative and established objective response criteria to evaluate Xilonix™, grew out of collaboration between XBiotech and the Scientific Advisory Group of the European Medicines’ Agency (EMA). The regulatory path was devised around an EMA Mandate to find new and better measures of efficacy for anti-tumor agents in treating patients with advanced cancer.
New clinical endpoints were developed based on findings from an earlier study where cancer patients receiving the antibody exhibited remarkable symptomatic recovery that in turn was associated with marked improvement in overall survival.
Study results showed a 76 percent relative improvement in response rate in patients treated with Xilonix™ compared to placebo.
Based on the Phase III results, which have been published in The Lancet Oncology, XBiotech is now seeking marketing approval for Xilonix™ in European Union member countries.
A Global Phase III study for Xilonix™ in advanced colorectal cancer patients under U.S. FDA regulatory guidance has completed enrollment. The candidate therapy, which received Fast Track designation by the U.S. FDA, will evaluate Xilonix™ treatment effect on overall survival in colorectal patients.
In February 2017, an Independent Data Monitoring Committee (IDMC) performed a prospectively planned, unblinded analysis of the Phase 3 study data and reported no safety concerns and that indications of efficacy were sufficient to recommend proceeding with the study without modification. This was the first of two interim efficacy analyses planned prior to the final analysis for overall survival. Survival analyses are to be performed after 276 (50%), 414 (75%) and 552 (100%) events at the respective stages. The study may be stopped for efficacy or futility at the second remaining interim analysis, and patients are otherwise followed for up to 18 months in order to determine overall survival. The study is powered for 552 events at conclusion.
Patients enrolled in this study were randomized 2:1 to receive Xilonix or placebo plus, in each case, best supportive care. Advanced colorectal cancer patients are required to have previous failed regimens that included flouropyrimidines, oxaliplatin, irinotecan, and Cetuximab (or Panitumumab for patients with KRAS mutation). Patients are expected to continue in the study until there is evidence of radiographic progression.