Pitolisant Shows Promise for Prader-Willi Syndrome Symptoms

Harmony Biosciences Holdings Inc presented new secondary endpoint data, including improvements in behavioral disturbances, from its phase 2 signal-detection study evaluating pitolisant for the treatment of excessive daytime sleepiness (EDS) in Prader-Willi syndrome (PWS), at the 2023 Foundation for Prader-Willi Research Symposium and Family Conference. 

The company also announced that it anticipates initiating its phase 3 registrational TEMPO study during the fourth quarter.

The poster presentation of secondary outcomes data included improvements in behavioral symptoms (as measured by the Aberrant Behavioral Checklist-2), especially in the higher-dose pitolisant group. Reductions in the caregiver rating of EDS severity were also observed as were some improvements in hyperphagia, even though baseline hyperphagia scores were in the normal to mild range. The overall rate of adverse events was similar for pitolisant and placebo, and the safety/tolerability profile was consistent with the known profile for pitolisant.

“We recognize the urgency for innovative treatments that help alleviate the profound unmet medical needs of individuals with PWS and their dedicated caregivers,” says Kumar Budur, MD, chief medical officer at Harmony Biosciences, in a release. “This is particularly crucial given the absence of an FDA-approved treatment for EDS in PWS, coupled with the prevalent and severe behavioral symptoms associated with this condition. We are encouraged by these findings from our phase 2 signal-detection study, which build upon the favorable primary study outcome and provide additional hope to this community as we pursue a potential new indication for pitolisant.”

The results from the phase 2 signal-detection study informed the protocol design for the upcoming phase 3 registrational TEMPO study, a randomized, double-blind, placebo-controlled, multicenter, global clinical study that will further assess the safety and efficacy of pitolisant in patients with PWS, ages 6 years and older. There are currently 15,000–20,000 people in the US living with PWS, according to a release from Harmony Biosciences, with more than half of them experiencing EDS and the majority having behavioral disturbances.

Pitolisant is marketed as WAKIX in the US and is FDA-approved to treat EDS or cataplexy in adult patients with narcolepsy. Pitolisant is not approved for use in patients with PWS and is currently being evaluated as an investigational agent in this patient population.