Soleno Therapeutics announces publication of results from pivotal study of Vykat XR in the Journal of Clinical Endocrinology and Metabolism

Soleno Therapeutics Inc. announced a publication in the peer-reviewed Journal of Clinical Endocrinology and Metabolism (JCEM). The paper, titled, “Diazoxide Choline Extended-Release Tablets in Prader-Willi Syndrome: A Randomized, Double-Blind, Placebo-Controlled, Withdrawal Period Study,” details results from the 16-week randomized withdrawal study (C602-RWP) of Vykat XR (also known as diazoxide choline extended-release tablets, or DCCR) in children and adults 4 years and older with hyperphagia in Prader-Willi syndrome (PWS).

The randomized withdrawal period study was a key part of the comprehensive Phase III clinical program that established the efficacy and safety of Vykat XR and supported its approval by the FDA as the first and only treatment for hyperphagia in people living with PWS. This clinical program included 127 participants with over 400 patient years of drug exposure, including individuals with nearly six years of continuous treatment.

The 16-week, randomized withdrawal period study included 77 individuals who previously completed 13-week placebo-controlled and long-term open-label Phase III studies. Participants were randomized 1:1 to either Vykat XR (n=38) or placebo (n=39). The primary endpoint was Hyperphagia Questionnaire for Clinical Trials (HQ-CT) total score change from baseline to week 16. Secondary endpoints included Clinical Global Impression of Severity (CGI-S) and Improvement (CGI-I); exploratory endpoints included weight and body mass index (BMI) z-score.

Key highlights from the publication:

• •Hyperphagia worsened significantly when treatment with DCCR was withdrawn, compared to continued DCCR administration. Statistically significant increases (worsening) in HQ-CT from baseline to week 16 were observed with placebo versus DCCR (P=0.0022).
• •CGI-S and CGI-I scores favored DCCR and approached, but did not reach, statistical significance.
• •Consistent with the hyperphagia response, the placebo cohort gained more weight and increased their BMI z-score more than the DCCR cohort (LS mean weight difference (95% confidence interval) -1.6 kg (-3.1, -0.1); LS mean z-score difference -0.09 (-0.17, -0.01).
• •Adverse events were similar with both arms, with no serious adverse events in the DCCR treatment arm. No participant experienced an adverse event leading to study drug discontinuation.

“This important study provided additional controlled data confirming the safety and efficacy of VYKAT XR in people with PWS, and we are pleased that the positive results have been accepted for publication in JCEM, the world’s leading peer-reviewed journal focused on cutting-edge endocrine and metabolic research,” said Dr. Anish Bhatnagar, Chief Executive Officer and Chairman of the Board of Soleno Therapeutics. “Our strong momentum since commercial launch reflects both the significant unmet need that VYKAT XR addresses as the first FDA-approved treatment for the hallmark feature of PWS – hyperphagia – as well as the meaningful therapeutic benefit that it can offer to people living with this rare and complex genetic condition.”

Dr. Jennifer Miller, Professor of Pediatric Endocrinology at the University of Florida, Gainesville and lead author of the paper, added, “The compelling results of the randomized withdrawal study highlighted in JCEM further reinforce the meaningful and sustained benefit of VYKAT XR in people living with hyperphagia caused by PWS. Notably, when study participants were transitioned to placebo during the randomized withdrawal study, we observed a significant worsening of hyperphagia, compared with those who remained on treatment with VYKAT XR. These results underscore the critical role that VYKAT XR can play in addressing hyperphagia, the most debilitating and distressing symptom of PWS, where no other effective therapeutic options are currently available.”

See- Miller JL , Bridges N, Felner EI et al. Diazoxide Choline Extended-Release Tablets in Prader-Willi Syndrome: A Randomized, Double-Blind, Withdrawal Period Study, J Clin Endocrinol Metab 2026;, dgaf661, https://doi.org/10.1210/clinem/dgaf661