FDA approves Emcitate, the first treatment for MCT8 deficiency
Egetis Therapeutics' tiratricol treats the excess blood thyroid hormone of Allan-Herndon-Dudley syndrome. The company also received a rare pediatric disease priority review voucher.
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The U.S. Food and Drug Administration on September 28 approved Emcitate (tiratricol) tablets for oral suspension to treat peripheral thyrotoxicosis in patients with MCT8 deficiency, also known as Allan-Herndon-Dudley syndrome. The FDA says Emcitate is the first therapy it has approved to treat symptoms of the disease. Egetis Therapeutics holds the approval, which covers adults and pediatric patients.
The disease and the drug
MCT8 deficiency is a rare genetic disorder that mainly affects males. According to the FDA, the MCT8 protein carries thyroid hormone into the brain. When it fails, the brain gets too little hormone while excess hormone builds up in the blood, which strains the heart and metabolism. Tiratricol can enter cells without the broken transporter, and it lowers the elevated blood thyroid hormone levels.
Emcitate is taken once a day as a liquid suspension, by mouth or through a feeding tube. The FDA lists diarrhea, vomiting, rash and excessive sweating as the most common side effects, and says Emcitate should not be used together with another thyroid medication. Egetis says it is not recommended for primary hypothyroidism.
The evidence
The FDA says it evaluated two studies in patients from infants to adults: an international, randomized, placebo-controlled trial and a longer-term open-label study. The FDA names the controlled trial as NCT05579327. On ClinicalTrials.gov, that record is ReTRIACt, a completed Phase 3 trial of tiratricol withdrawal in 20 males, sponsored by Rare Thyroid Therapeutics International AB. Its primary outcome is the change in serum total T3 during a 30-day double-blind period.
Egetis lists the full program behind the approval as ReTRIACt, Triac Trial I, Triac Trial II, the Erasmus Medical Center Cohort Study, the EMC Survival Study and the U.S. Expanded Access Program.
Designations and business terms
Emcitate had Orphan Drug, Rare Pediatric Disease, Fast Track and Breakthrough Therapy designations, and Priority Review. With the approval, the FDA granted Egetis a Rare Pediatric Disease Priority Review Voucher. Egetis says it will explore a sale of the voucher, possibly in the fourth quarter of 2026, subject to market conditions.
What to watch
Egetis expects Emcitate to be commercially available in the U.S. eight to ten weeks after approval, with a patient support program run with PANTHERx Rare. The company says the drug already has a marketing authorization in the European Union.