Tonix Pharmaceuticals Holding Corp. (NASDAQ: TNXP) announced the enrollment of the first patient in the HORIZON Phase 2 trial evaluating TNX-102 SL 5.6 mg as a first-line monotherapy for adults with major depressive disorder (MDD). The randomized, double-blind, placebo-controlled study is expected to enroll approximately 360 patients at about 30 U.S. sites. The trial will assess changes in depression severity after six weeks of treatment, along with measures of sleep quality, anxiety and global clinical improvement.
TNX-102 SL is designed to improve sleep quality, which the company believes plays an important role in MDD. The therapy is already approved by the FDA under the brand name TONMYA (cyclobenzaprine HCl sublingual tablets 2.8mg) for the treatment of fibromyalgia in adults. Tonix said the therapy has previously shown signals for improving depressive symptoms and subjective sleep quality in earlier clinical studies. The drug is also being developed for several additional indications, including post-traumatic stress disorder, Long COVID, alcohol use disorder and agitation in Alzheimer’s disease.
The initiation of this Phase 2 trial marks a significant step for Tonix as it seeks to expand the therapeutic use of TNX-102 SL beyond fibromyalgia. Major depressive disorder affects millions of people worldwide, and many patients do not achieve adequate response with current treatments. By targeting sleep quality as a core component of MDD, TNX-102 SL offers a novel approach that could differentiate it from existing antidepressants. The company’s fully-integrated commercial infrastructure, which supports its marketed products including Zembrace SymTouch and Tosymra for acute migraine, positions it to potentially bring this therapy to market if trials are successful.
Tonix is also advancing a pipeline of immunology programs, including monoclonal antibody TNX-4800 for Lyme disease prophylaxis and TNX-1500, a third-generation CD40 ligand inhibitor for the prevention of kidney transplant rejection. The company’s CNS portfolio includes TNX-2900, which is Phase 2 ready for the treatment of Prader-Willi syndrome, a rare disease.
The HORIZON trial’s results will be closely watched by investors and clinicians. If positive, TNX-102 SL could become a first-line monotherapy for MDD, addressing a high unmet need. The study’s focus on sleep quality as a key endpoint aligns with growing recognition of sleep disturbances in depression. For more information, visit the company’s newsroom at https://nnw.fm/TNXP.
This announcement underscores Tonix’s commitment to developing treatments for central nervous system conditions with limited options. The company’s ability to leverage existing FDA-approved formulations could accelerate development timelines.
