The once-daily sublingual treatment targets pain, fatigue, and sleep disruption.
The US Food and Drug Administration has approved the first new therapy for fibromyalgia in more than 15 years.
Cyclobenzaprine HCl (Tonmya) is a first-in-class, non-opioid, once-daily skeletal muscle relaxant structurally related to tricyclic antidepressants, with a rapid-acting sublingual formulation designed for absorption directly into the bloodstream.
The approval was based on data from two pivotal Phase 3 trials, RELIEF and RESILIENT, which involved about 1000 adults.
Across both studies, Tonmya significantly reduced daily pain scores at 14 weeks compared with placebo, and a higher proportion of patients achieved a clinically meaningful (≥30%) reduction in pain.
Across three Phase 3 trials including more than 1400 participants, Tonmya was generally well tolerated. The most common adverse events occurring at a higher incidence than placebo included oral hypoesthesia, oral discomfort, abnormal taste, somnolence, oral paraesthesia, oral pain, fatigue, dry mouth and aphthous ulcers.
Results of the latest Phase 3 trial, RESILIENT, was recently published in Pain Medicine with data on primary and secondary endpoints measuring pain, patient’s global impression of change, patient-reported symptoms and function, sleep disturbance and fatigue.
The authors noted that the US FDA last approved a new fibromyalgia pharmacotherapy in 2009.
“The fibromyalgia therapies approved for pain have limited efficacy for improving both sleep quality and fatigue, potentially contributing to polypharmacy and increased opioid use,” they wrote.
“Many patients report dissatisfaction with fibromyalgia treatment and discontinue owing to adverse events (AEs) or lack of efficacy. Given the modest efficacy and poor tolerability of current therapies, there remains a significant need for more tolerable therapies that provide long-term, broad symptom relief.”
The authors said treatment with cyclobenzaprine was associated with significant improvements in core symptoms of widespread pain, disturbed sleep and fatigue in patients with fibromyalgia and was generally safe and well tolerated.
Dr Philip Mease, director of Rheumatology Research at the Providence Swedish Medical Centre and Clinical Professor at the University of Washington School of Medicine, welcomed the announcement.
“For many years, rheumatologists like myself and other healthcare professionals have had to manage fibromyalgia with limited options that do not adequately meet treatment needs for the majority of patients,” he said.
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“Tonmya is a novel treatment approach that targets nonrestorative sleep that is characteristic of fibromyalgia and can impact core symptoms, specifically pain.”
Associate Professor Andrea Chadwick, of the University of Kansas’s Anaesthesiology, Pain and Perioperative Medicine Department, said the sublingual formulation was a big advantage.
“I know first-hand how the chronic pain of fibromyalgia significantly disrupts my patients’ lives,” she said.
“Treatments that are processed through the liver can result in metabolites that could affect a medicine’s efficacy and safety over time. Tonmya is administered sublingually which is designed to reduce pain quickly and durably with a tolerable safety profile.”
Tonmya is expected to be available for adult patients in the US beginning in the fourth quarter of this year.
