FDA Places Partial Hold on Trial Evaluating BLU-222 in Advanced Solid Cancers

The Food and Drug Administration (FDA) has placed a partial clinical hold on the phase 1/2 VELA trial evaluating BLU-222 in patients with advanced solid cancers, due to visual side effects observed in a limited number of patients, according to a press release from Blueprint Medicines, the drug’s manufacture.

The reported side effects included short-term, reversible episodes of light sensitivity and blurred vision. All events were mild, except for one which was severe, and were resolved with dose interruption or reduction. There were no treatment-emergent abnormal findings, including uveitis (a form of eye inflammation), observed in patients who had received detailed eye exams.

"Patient safety is our first priority, and we are working closely with the FDA to investigate the reported visual adverse events as well as amend the VELA trial protocol to provide specific guidance to investigators on how to monitor for and manage these events should they occur," said Dr. Becker Hewes, Chief Medical Officer at Blueprint Medicines, in the release. "We have confidence in the benefit-risk profile of BLU-222 based on the activity and safety data we have seen to date in the dose escalation study. In addition, we recognize the urgency to treat patients with CDK2-vulnerable cancers, many of whom have seen their disease progress after exhausting all other options, and we aim to resume enrollment as expeditiously and responsibly as possible."

The trial is currently evaluating BLU-222 in an estimated 366 patients with one of the following advanced solid cancers: ER-positive breast cancer, HER2-negative breast cancer, ovarian, endometrial and gastric cancers, esophageal adenocarcinoma and carcinosarcoma.

The partial hold means patients who are enrolled are still receiving the study drug at this time, and no additional patients will be enrolled until it is lifted. The drug is being evaluated in a phase 1 dose escalation portion of the trial, which has shown evidence of clinical benefit with no discontinuations due to side effects.

Blueprint Medicines plans to present initial dose escalation data from the trial in the first half of this year.

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