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Addressing Fibromyalgia Sleep and Pain With TNX-102 SL Approval: Q&A With Philip Mease, MD
Mease discussed his hopes for the new approval's impact on the fibromyalgia field.
On August 15, 2025, the US Food and Drug Administration (FDA) approved TNX-102 SL under the name Tonmya, marking the first new fibromyalgia therapy in over 15 years. Developed by Tonix Pharmaceuticals, TNX-102 SL is a sublingual formulation of cyclobenzaprine and the first member of a new class of non-opioid analgesics for the condition. Its approval represents a pivotal step forward for millions of patients living with chronic, often debilitating pain, fatigue, and nonrestorative sleep.
The FDA decision was supported by phase 3 RESILIENT trial data, which demonstrated significant reductions in daily pain scores as early as week 1, sustained through week 14 (P <.0001). Patients on TNX-102 SL also experienced improvements in sleep disturbance, fatigue, and overall sleep quality, with effect sizes ranging from 0.32–0.50. Importantly, the therapy showed a tolerable safety profile, with discontinuations due to adverse events occurring in just 6.1% of treated patients.
In this Q&A, Philip Mease, MD, director of Rheumatology Research at Providence Swedish Medical Center and clinical professor at the University of Washington School of Medicine, shared insights on how TNX-102 SL may reshape fibromyalgia care, its unique mechanism targeting sleep-related symptoms, and the broader implications for treating nociplastic pain.
HCPLive: How do you anticipate integrating TNX-102 SL into current treatment paradigms for fibromyalgia?
Philip Mease, MD: Assuming that the cost to the patient will not be exorbitant, assuming insurance coverage, and that there will be a reasonably non-onerous prior authorization process, we do plan to prescribe TNX-102 SL in our practice, based on the efficacy and safety data demonstrated in the phase 3 trials. I am aware that some rheumatologists have commented that it will just be an expensive version of generic, oral cyclobenzaprine, but the fact that it was able to show statistical separation from placebo and has a unique mechanism of action that yields more enduring effect during the nighttime’s sleep cycles, and that its bioavailability is greater, all add up to our wanting to use it. Many rheumatologists prefer not to see fibromyalgia patients for whom that is the primary diagnosis, because of their complexity, but since fibromyalgia is a concomitant condition in up to 20% of most rheumatologic conditions, rheumatologists end up managing the condition quite frequently. Since patients may not have had success, or have lost effect from previously tried approved FM medications, such as duloxetine, I would expect clinicians to reach for a newly approved treatment, again assuming the prior authorization is not too onerous.
How does TNX-102 SL’s sublingual cyclobenzaprine formulation targeting nonrestorative sleep differs from previous therapies, and why does this matter for treating core fibromyalgia symptoms?
Mease: A core symptom and sign of FM is disturbance in sleep physiology, as shown so well by the late Harvey Modolfsky at the University of Toronto. Tonmya has similar biology as the older treatments such as the tricyclic, amitriptyline, which has overlapping mechanistic features with generic cyclobenzaprine and TNX-102 SL. TNX-102 SL appears to have some superior effect to generic cyclobenzaprine in more enduring effect during the full night time sleep cycle, peaking at 5 hours into sleep, and not having residual effect during the day. Another feature is that there is less of the metabolite, norcyclobenzaprine, that has a longer half life than cyclobenzaprine, competes for the same receptors as cyclobenzaprine, and has a lesser effect.
TNX-102 SL is a first-in-class, non-opioid approach in fibromyalgia— what further potential do you think this type of drug has in the field?
Mease: Many rheumatologic patients have “residual” pain even when immunomodulatory drugs demonstrate good effect on signs of inflammation. Much of this could be due to central sensitization. To the extent that sleep disturbance is part of the central sensitization phenomenon, then TNX-102 SL could be used concomitantly to try to reduce residual pain.
What further research are you looking forward to with TNX-102 SL?
Mease: I look forward to seeing RWE from long term clinical registries, to see if addition of this medication makes a difference, in settings not as controlled as clinical trials, with even more complex patients, there is improvement of pain, fatigue, and sleep disturbance. [In terms of other investigations with] long COVID and PTSD... there is overlapping pathophysiology with FM, including features of pain, fatigue and sleep disturbance, so I think it is worthwhile to consider use of this drug in these and other conditions that are at least partially characterized as central sensitization.
Given the complexity and heterogeneity of fibromyalgia, what do you think are the most pressing unmet needs that remain in the field past this approval?
Mease: One of the big issues we are addressing in the OMERACT chronic pain working group, which I help co-chair, is education of clinicians, and patients, that pain is complex and often includes the phenomenon of central sensitization. That type of pain is termed “nociplastic” pain. This type of pain may need different approaches to effectively treat. So whilst immunomodulatory medicines may effectively treat inflammation and reduce classic nociceptive pain, adjunctive approaches may be needed to treat nociplastic pain. This may also reduce the tendency to keep changing the patient’s immunomodulatory medicine, if inflammation is well controlled. Along with this education, we are hoping to see measures of nociplastic pain used in clinical trials and in clinical practice to aid clinicians to navigate this complexity.
This transcript has been edited for clarity.
