The Food and Drug Administration (FDA) has issued a Complete Response Letter (CRL) to Levo Therapeutics regarding the New Drug Application for LV-101 (intranasal carbetocin) for the treatment of hyperphagia, anxiousness, and distress associated with Prader-Willi syndrome.

LV-101 is an investigational intranasal formulation of carbetocin, an analogue of oxytocin. The application included data from the phase 3 CARE-PWS study ( Identifier: NCT03649477), which evaluated the effects of LV-101 in patients 7 to 18 years of age with genetically-confirmed PWS.

Results showed that the study did not meet its primary endpoints (change in hyperphagia and change in obsessive/compulsive behaviors at the 9.6mg dose), though statistical significance was achieved with the 3.2mg dose as evaluated by the Hyperphagia Questionnaire for Clinical Trials score (secondary endpoint; P =.016). The 3.2mg dose was also associated with improvements across other key secondary endpoints.

In the CRL, the FDA’s Division of Psychiatry concluded that, “while LV-101 appears to be generally safe and well tolerated, the efficacy data available for the proposed 3.2mg dose of LV-101 were insufficient for approval.” To confirm the results of the 3.2mg dose, the FDA is recommending an additional clinical study.

“We are disappointed by the outcome of FDA’s review of our application and the continued lack of treatments for the most significant symptoms of the syndrome,” said Sara Cotter, CEO of Levo Therapeutics. “We are hopeful that our discussions with FDA regarding the next study will be productive and that we can initiate enrollment of a confirmatory study later this year.”


  1. Levo Therapeutics receives Complete Response Letter from FDA for its New Drug Application for LV-101 (intranasal carbetocin) for the treatment of Prader-Willi syndrome. News release. Levo Therapeutics. January 18, 2022. Accessed January 19, 2022.
  2. Levo Therapeutics announces top-line results from phase 3 CARE-PWS study of LV-101 (intranasal carbetocin) for the treatment of Prader-Willi Syndrome. News release. Levo Therapeutics. August 6, 2020.