Flex Pharma Inc has completed enrollment of its human proof-of-concept efficacy study in nocturnal leg cramps (NLC) with its chemically synthesized, single molecule, transient receptor potential (TRP) ion channel activator, formulated as an orally disintegrating tablet. Subject enrollment for this study initiated in late May and completed ahead of plan. This randomized, blinded, controlled, cross-over study is designed to evaluate the safety and efficacy of its single agent in over 50 subjects who suffer from frequent nocturnal leg cramps. Topline results are expected by year end.

“The rapid enrollment into this study underscores the substantial unmet need for a therapeutic agent for people who suffer from frequent leg cramps at night,” says Flex Pharma chief medical officer Thomas Wessel, MD, PhD, in a release. Wessel served as the medical lead for three products approved in United States: Razadyne, Lunesta, and Ampyra. “Given the underlying mechanism of alpha motor neuron hyperexcitablity in cramps and spasms, we have also initiated a Phase 2 study with our single agent for patients with MS, and we expect to begin our Phase 2 study in ALS patients later this year.” These studies in MS and ALS will be conducted outside the United States.

“Flex Pharma’s agent is the leading clinical candidate for NLC and I am hopeful that their efforts will ultimately help the millions of people who suffer from this painful condition and currently have no safe and effective therapeutic options,” says John Winkelman, MD, PhD, chief of the Sleep Disorders Clinical Research Program at Massachusetts General Hospital and Flex Pharma Scientific Advisory Board member, who was involved in the clinical development of both Requip and Mirapex, approved agents for restless legs syndrome (RLS).

The current study builds upon a completed, successful, randomized, controlled, blinded cross-over study (n=50), in which the company’s extract formulation demonstrated statistically significant positive human efficacy on the key endpoints. Results from that study were accepted and presented as a late-breaker at the American Academy of Neurology Annual Meeting in April 2016.