FDA Approves Emcitate (tiratricol) for MCT8 Deficiency

The U.S. Food and Drug Administration (FDA) has approved Emcitate (tiratricol) tablets for oral suspension to treat peripheral thyrotoxicosis in patients with MCT8 deficiency, also known as Allan-Herndon-Dudley syndrome. This is the first FDA-approved treatment for the symptoms of this rare, devastating genetic disease.

MCT8 deficiency is a rare genetic disorder that primarily affects males. It is caused by a faulty gene that provides instructions for making the MCT8 transporter, a protein responsible for carrying thyroid hormone into the brain. Because thyroid hormone cannot cross the blood-brain barrier without the MCT8 transporter, the brain receives too little of this hormone while excessive levels build up in the bloodstream. Patients with this condition often experience debilitating effects, including the inability to walk or sit independently, absent or severely limited speech, intellectual disability, feeding difficulties, and chronic stress on the heart and metabolism.

Emcitate was granted Orphan Drug, Rare Pediatric Disease, Fast Track, and Breakthrough Therapy designations as well as Priority Review. The approval was granted to Egetis Therapeutics US Inc.

The effectiveness of Emcitate was evaluated in two clinical studies in patients ranging in age from infants to adults, including an international, multi-center, randomized, placebo-controlled trial (NCT05579327) and a longer-term open-label study. Across both studies, patients treated with Emcitate had reductions in excess thyroid hormone levels in the bloodstream and improvements in cardiovascular and metabolic symptoms impacted by thyroid levels, such as systolic blood pressure and heart rate.

Emcitate is taken once daily as a liquid suspension, either by mouth or through a feeding tube for patients who have difficulty swallowing. The most common side effects reported were diarrhea, vomiting, rash, and excessive sweating. Patients taking another thyroid medication should talk to their healthcare provider before starting Emcitate, as the two should not be used together.