Negative FDA AdCom vote for Y-mAbs' omburtamab

US biotech Y-mAbs Therapeutics (Nasdaq: YMAB) saw its shares plunge more than 30% to $6.20 in after-hours trading on Friday, after it announced a negative outcome of the US Food and Drug Administration (FDA) Oncologic Drugs Advisory Committee (ODAC) meeting, which reviewed investigational Omblastys (131I-omburtamab) for the treatment of CNS/leptomeningeal metastasis from neuroblastoma.

The committee voted 16 to 0 that the company had not provided sufficient evidence to conclude that omburtamab improves overall survival.

The outcome was not surprising as, on October 26, the FDA posted briefing documents regarding omburtamab, stating there were “significant questions" as to the adequacy and control of the submitted study, sending the firm’s shares tumbling 27% at that time. This is not the first set-back Y-mAbs has received for omburtamab. In October 2020, the FDA had issued a Refusal to File letter, leading Y-mAbs to resubmit its application for the drug on April 1, 2022.