Efficacy and Safety of TNX-102 SL (Sublingual Cyclobenzaprine) for the Treatment of Fibromyalgia: Results From the Randomized, Placebo-Controlled RELIEF Trial.

OBJECTIVE: To evaluate the efficacy and safety of TNX-102 SL, a once-nightly sublingual formulation of cyclobenzaprine, in reducing pain in patients with fibromyalgia.

METHODS: RELIEF was a double-blind, randomized, placebo-controlled trial. Overall, 503 patients received TNX-102 SL 2.8 mg for 2 weeks, followed by 5.6 mg for 12 weeks (248 patients), or matching placebo (255 patients). The primary endpoint was change from baseline at week 14 in weekly average of daily pain scores. Secondary endpoints included Patient Global Impression of Change (PGIC) scores, Fibromyalgia Impact Questionnaire Revised (FIQR) scores, Patient-Reported Outcomes Measurement Information System (PROMIS) Sleep Disturbance and Fatigue scores, and daily sleep quality. Safety was assessed by adverse events (AEs).

RESULTS: Reduction in daily pain from baseline at week 14 was significantly greater with TNX-102 SL (LS mean change [95% CI], -1.9 [-2.1 to -1.7]) vs placebo (-1.5 [-1.7 to -1.3]; P=0.01). TNX-102 SL was not associated with significant improvement in PGIC at week 14 but was associated with improvements in FIQR scores, PROMIS scores, and daily sleep quality. Overall, 59.7% of patients receiving TNX-102 SL and 46.3% receiving placebo reported treatment-emergent AEs; the most common were oral hypoesthesia (17.3% with TNX-102 SL vs 0.4% with placebo), oral paresthesia (5.6% vs 0.4%, respectively), and product taste abnormal (4.4% vs 0.4%, respectively).

CONCLUSIONS: In this phase 3, randomized, controlled trial of patients with fibromyalgia, treatment with TNX-102 SL was associated with significant reductions in daily pain and was safe and well tolerated.