Tonix Pharmaceuticals Holding Corp. is one step closer to potentially providing a new treatment option for fibromyalgia patients as the U.S. Food and Drug Administration (FDA) has set a Prescription Drug User Fee Act (PDUFA) goal date of August 15, 2025, for its decision on the marketing approval of TNX-102 SL (cyclobenzaprine HCl sublingual tablets). TNX-102 SL is a non-opioid, centrally-acting analgesic designed for bedtime dosing. If approved, TNX-102 SL could be the first new drug for treating fibromyalgia in more than 15 years and the first member of a new class of analgesic drugs for the condition.
Clinical Efficacy and Safety
The New Drug Application (NDA) is supported by data from two 14-week double-blind, randomized, placebo-controlled Phase 3 clinical trials. The first Phase 3 trial, RELIEF, completed in December 2020, met its pre-specified primary endpoint of significantly reducing daily pain compared to placebo (p=0.010). The confirmatory Phase 3 RESILIENT study, completed in December 2023, also met the pre-specified primary endpoint of significantly reducing daily pain compared to placebo (p =0.00005).
In both trials, TNX-102 SL was generally well tolerated with an adverse event profile comparable to prior studies and with no new safety signals observed. The most common treatment-emergent adverse event was tongue or mouth numbness at the administration site, which was temporally related to dosing, self-limited, never rated as severe, and rarely led to study discontinuation (one participant in each study). Excluding COVID-19, systemic adverse events in each of the two studies were lower than 4.0%.
Addressing Unmet Needs in Fibromyalgia
Fibromyalgia is a chronic pain disorder affecting more than 10 million adults in the U.S., with the majority being women. Symptoms include chronic widespread pain, non-restorative sleep, fatigue, and cognitive dysfunction. “The fibromyalgia community…has been waiting for a new drug for over 15 years,” said Seth Lederman, M.D., Chief Executive Officer of Tonix Pharmaceuticals. He also noted that analysis of insurance claims has shown that fibromyalgia patients were more likely to be prescribed addictive opioids than all three of the FDA-approved drugs combined.
Fast Track Designation
TNX-102 SL has been granted Fast Track designation by the FDA, designed to expedite the review of important new drugs to treat serious conditions and fill an unmet medical need. TNX-102 SL targets the non-restorative sleep characteristic of fibromyalgia through its action as an antagonist at multiple neuroreceptor subtypes, including serotonergic, adrenergic, histaminergic, and muscarinic receptors. The sublingual tablet formulation of cyclobenzaprine hydrochloride is designed for bedtime dosing.
