Exelixis and Bristol-Myers Squibb achieved positive Phase II data showing that XL184 demonstrated activity in patients with glioblastoma multiforme (GBM), the most common and aggressive form of brain cancer. The study evaluated the safety, tolerability, and clinical activity of XL184 at daily doses of 175 mg or 125 mg in 46 patients with previously treated GBM, including some patients who had received prior antiangiogenic therapy.

The overall rate of confirmed partial response in the patients treated at 175 mg was 17%. Among patients without prior antiangiogenic therapy, 21% achieved confirmed responses. In patients who had received prior antiangiogenic therapy, 8% progressed on vandetinib and achieved a confirmed partial response. Of the 46 patients treated at the 175 mg dose level, 21% attained 6-month progression-free survival (PFS) rate with 35% of patients censored for PFS at the time of analysis. The median duration of response was 5.9 months. The median PFS interval was 3.7 months.

“The updated data from patients treated with the 175 mg dose of XL184 is consistent with what we have reported previously and continue to demonstrate that the compound is clinically active,” said Michael M. Morrissey, Ph.D. president of R&D at Exelixis. “While the data from the 125 mg dose cohort are still early, they are encouraging and we will continue to evaluate the suitability of this dose and potentially others for future clinical studies. This trial in its totality is providing important information that will enable future decision making with respect to designing and implementing trials of XL184 in this patient population.”