Bright Minds Biosciences said on November 2 that the US Food and Drug Administration has placed its investigational new drug application for BMB-101 in developmental and epileptic encephalopathies on a partial clinical hold. The company learned of the hold by email from the agency. The planned study, Protocol BMB-101-105, was designed as a randomised, double blind, placebo controlled Phase 2 trial of ascending doses of BMB-101 in patients with seizures associated with these conditions, including paediatric enrolment.
The FDA cited toxicity observed in mice and inadequate pharmacokinetic and juvenile toxicity data to support the proposed paediatric enrolment. BMB-101 is a selective 5-HT2C agonist, a serotonin receptor also targeted by UCB’s Fintepla. No patients had been enrolled in the planned US study.
Bright Minds said it believes the mouse toxicity was not seen in other species and, based on its toxicology reports, peer review and independent expert opinion, that the findings were incidental and not drug related. The company stressed that this is its interpretation and does not resolve the agency’s concerns, that additional data or studies may be required, and that there is no assurance the hold will be lifted. It believes the hold applies only to the planned US Phase 2 study and that its other ongoing trials are unaffected.
The shares fell sharply on the disclosure. The next step is documentary: the FDA’s formal partial clinical hold letter is due within 30 days and is expected to set out the agency’s requirements in detail, after which the timeline for the programme depends on whether existing data can answer the objections or new juvenile toxicity work is needed.