Soleno Therapeutics, Inc. (NASDAQ:SLNO) has announced the successful completion of a scientific advice meeting with the U.S. Food and Drug Administration (FDA) regarding its Diazoxide Choline Controlled-Release (DCCR) tablet for the treatment of Prader-Willi syndrome (PWS). The FDA's feedback provides a clearer regulatory pathway for DCCR, a potential treatment for this rare and complex genetic disorder.
FDA Agreement on Key Trial Aspects
Soleno presented data from a Phase II study of DCCR in PWS patients, along with data from other DCCR studies. The FDA expressed support for using the change in hyperphagia score (without a change in weight) compared to placebo as the primary endpoint. This is a significant development, as hyperphagia is a hallmark symptom of PWS, characterized by a chronic feeling of insatiable hunger. The FDA also accepted the company's proposed dosing paradigm for the study.
Optimized Trial Duration and Design
In a notable agreement, the FDA proposed, and Soleno accepted, that the randomized, double-blind, placebo-controlled study duration be shortened to 3-4 months. DCCR safety information can be gathered in a long-term, safety extension study. This adjustment could expedite the development timeline and reduce the overall burden on patients participating in the trial.
Phase III Trial Design and Timeline
Based on the FDA's guidance, Soleno will finalize the design of a Phase III, randomized, double-blind, placebo-controlled study involving approximately 100 patients. The company anticipates initiating the study, pending final FDA agreement, by the end of 2017, with an expected completion time of 9-12 months. Further regulatory input is being sought on other aspects of the late-phase development program.
Management Perspective
"We are pleased with the positive outcome of this meeting and the constructive guidance received from the FDA," said Anish Bhatnagar, M.D., Chief Executive Officer of Soleno. "We now have a clearer understanding of the regulatory pathway for DCCR in the U.S. for the treatment of PWS... We remain committed to the development of DCCR, which, if approved, could provide the desperately needed treatment for this life-threatening condition."
About Prader-Willi Syndrome
PWS is a rare genetic neurobehavioral and metabolic disorder affecting approximately 1 in 15,000 to 25,000 live births. It is characterized by hyperphagia, behavioral problems, cognitive disabilities, low muscle tone, short stature, excess body fat accumulation, developmental delays, and incomplete sexual development. Hyperphagia leads to significant morbidities, including stomach rupture, obesity, diabetes, and cardiovascular disease, and can increase mortality due to choking or accidental death related to food-seeking behavior. Currently, there are no approved therapies to treat the hyperphagia, metabolic, cognitive, or behavioral aspects of PWS.
About DCCR
DCCR is a novel, proprietary controlled-release, crystalline salt formulation of diazoxide, designed for once-daily oral administration. Diazoxide, as an oral suspension, has been used for decades in treating rare diseases in neonates, children, and adults, though not specifically for PWS. Soleno holds extensive patent protection for the therapeutic use of diazoxide and DCCR in PWS patients. The DCCR development program is supported by positive data from two completed Phase II clinical studies and six Phase I clinical studies in various metabolic indications, as well as a pilot study in PWS patients, where DCCR showed promise in addressing hyperphagia.
