By Colin Kellaher

Neurogene is proceeding with a scaled-back study of its proposed NGN-401 gene therapy for the rare genetic neurological disorder Rett syndrome after a serious adverse event left a study participant in grave condition.

Neurogene on Monday said the U.S. Food and Drug Administration has completed a review of the safety data for NGN-401 and is allowing the New York company to proceed with the Phase 1/2 trial study using the low-dose cohort.

Neurogene last week reported that it had become aware of an emerging treatment-related serious adverse event in a participant in the study's high-dose cohort, and the news sent its share price tumbling 44%.

The company on Monday said the patient experienced signs of a systemic hyperinflammatory syndrome, a rare and life-threatening immune response that has been reported with systemic exposure to high doses of a benign virus used to deliver genetic material, and is in critical condition.

Neurogene said it doesn't plan to enroll any further study participants at the high-dose level, and that it no longer expects to complete enrollment in the low-dose cohort by the end of the year as it updates the study protocol to reflect the discontinuation of the higher dose.

Neurogene shares, which traded as high as $74.49 earlier this month before the study setback, were recently down 7.3% to $32.01 in light premarket trading Monday.

Write to Colin Kellaher at colin.kellaher@wsj.com

(END) Dow Jones Newswires

November 18, 2024 07:34 ET (12:34 GMT)

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