XBiotech recently presented positive data from its pivotal Phase 3 clinical trial of Xilonix, the company’s monoclonal antibody immunotherapy for advanced colorectal cancer (CRC), at the 18th European Society of Medical Oncology (ESMO) World Congress on Gastrointestinal Cancer in Barcelona, Spain.
The double-blind, placebo-controlled Phase 3 trial evaluated 309 patients who were randomly assigned to receive treatment with Xilonix plus best supportive care (BSC) versus a placebo plus BSC for eight weeks. All patients taking part in the trial had failed all chemotherapy treatments and had metastatic disease, with one or more symptoms of metabolic dysfunction and functional impairment.
Results of the study showed a 76 percent relative improvement in response rate in patients treated with Xilonix compared to a placebo. In addition, patients treated with Xilonix were 53 percent more likely to have disease stability vs. a placebo.
The trial’s primary endpoint clinical response rate, which used both innovative and established objective response criteria to evaluate Xilonix, was developed in collaboration with the European Medicines Agency (EMA) Scientific Advisory Group as a means to determine the efficacy of Xilonix as an anti-cancer therapy in patients with advanced colorectal cancer.
“In this first-of-its-kind study, not only did treatment with Xilonix demonstrate clinical benefit but it was also very well-tolerated, suggesting Xilonix has the potential to meet the real and urgent need for more effective, less toxic therapies for patients with advanced colorectal cancer,” Dr. Tamas Hickish, chair of the Xilonix European Phase 3 Study and consultant medical oncologist at the Dorset Cancer Centre, and a visiting professor at Bournemouth University in England, said in a recent press release.
“In addition, this study provides evidence that novel endpoints based on symptom recovery can serve as a predictor of overall survival benefit and thus may be used to evaluate an anti-tumor agent in this disease,” Hickish added.
In addition to increased overall survival, patients that responded to the treatment gained more lean body mass compared to non-responders, had reduced fatigue and pain, and had a better appetite.
Control of thrombocytosis and systemic inflammation (IL-6) were also improved in patients who responded to the treatment vs. non-responders.
Treatment with Xilonix was well-tolerated, with an adverse event profile comparable to a placebo, and without drug-associated toxicity. The most common adverse events (AEs) related to the treatment were mild to moderate abdominal pain, weight loss, fatigue, decreased appetite, anemia, constipation, peripheral edema, asthenia, and nausea.
While the trial did not reveal a difference in serious adverse events (SAEs) between treatment groups, there was a 26 percent relative risk reduction of SAEs in the group of patients treated with Xilonix versus those treated with the placebo.
“There is an urgent need for new forms of anti-tumor, disease-modifying cancer therapies that effectively control disease while being less toxic,” said John Simard, XBiotech’s founder, president, and CEO. “We believe these data demonstrate that our True Human monoclonal antibody targeting interleukin-1 alpha has the potential to meet this critical need.”
