The FDA has extended the review period for Soleno Therapeutics' New Drug Application (NDA) for DCCR (diazoxide choline) extended-release tablets, a potential treatment for Prader-Willi syndrome (PWS) in patients aged four years and older who experience hyperphagia. The new Prescription Drug User Fee Act (PDUFA) target action date is now March 27, 2025.
The FDA's decision to extend the review period comes after determining that responses to recent information requests from Soleno constituted a major amendment to the NDA. This extension will allow the FDA additional time to thoroughly review the submitted information. Soleno submitted the NDA on June 27, 2024, and the FDA granted Priority Review in August 2024.
DCCR's Potential Impact on PWS
Prader-Willi syndrome is a rare genetic disorder affecting approximately 1 in 15,000 live births. A hallmark symptom of PWS is hyperphagia, characterized by an insatiable appetite, preoccupation with food, and an intense drive to consume food. This can lead to severe obesity, diabetes, cardiovascular disease, and reduced quality of life. According to the Prader-Willi Syndrome Association USA, hyperphagia was rated as the most important symptom to be relieved by a new medicine by 96.5% of parents and caregivers in a global survey.
DCCR is a novel, proprietary, once-daily, extended-release oral tablet containing diazoxide choline. The parent molecule, diazoxide, has been used for decades in treating rare diseases in neonates, infants, children, and adults, but is not approved for use in PWS. DCCR has been granted Breakthrough Therapy, Fast Track, and Orphan Drug designations in the U.S., as well as Orphan Drug Designation in the E.U. for the treatment of patients with PWS.
Clinical Data Supporting DCCR
The DCCR development program is supported by data from five completed Phase 1 clinical studies in healthy volunteers and three completed Phase 2 clinical studies, one of which was in individuals with PWS. In the PWS Phase 3 clinical development program, DCCR showed promise in addressing hyperphagia, as well as several other symptoms such as aggressive/destructive behaviors, fat mass, and other metabolic parameters.
Soleno's NDA is supported by data from several trials, including the Phase 3 DESTINY PWS study (NCT03440814) and its open-label extension study, dubbed C602 (NCT03714373). While the DESTINY PWS trial did not demonstrate a statistically significant difference in hyperphagia reduction overall, Soleno said that the DCCR group showed "nominally significant" reductions in fat mass, and overall improvements in condition as assessed by investigators.
Unmet Needs in PWS Treatment
Currently, there are no approved therapies to treat the hyperphagia, appetite, metabolic, cognitive function, or behavioral aspects of PWS. DCCR represents a potential new treatment option for managing hyperphagia and improving the lives of individuals with PWS and their families.
No Safety Concerns Raised
Importantly, the FDA did not cite any safety, efficacy, or manufacturing concerns in their correspondence regarding the extension. Soleno will continue to work closely with the FDA to address any remaining questions during the review period.
