New York, New York — November 3, 2025 — Leads & Copy — The Muscular Dystrophy Association (MDA) has achieved a significant milestone with the FDA approval of KYGEVVI® (doxecitine and doxribtimine), the first and only treatment for thymidine kinase 2 deficiency (TK2d), a rare and life-threatening mitochondrial myopathy affecting both adults and children.
UCB will handle the marketing of KYGEVVI® in the U.S. Angela Lek, PhD, interim Chief Research Officer at MDA, emphasized that the approval offers real hope for patients and families grappling with this devastating disease.
Data presented at the 2025 MDA Clinical & Scientific Conference indicated that KYGEVVI® significantly benefits individuals with TK2d, reducing the risk of death by over 90% for those with symptoms beginning at age 12 or younger. Additionally, 75% of these patients regained at least one previously lost motor skill, with many reducing or ceasing ventilatory support. The therapy was generally well-tolerated, with diarrhea being the most common side effect. The approval marks a life-changing moment, offering strength, time, and renewed hope.
MDA’s decades of research, clinical care, and advocacy were crucial in establishing the field of neuromuscular disease research and care. Early MDA research funding supported Dr. Michio Hirano at Columbia University in developing a TK2-deficient mouse model, proving targeted treatments could restore mitochondrial function. In 2024, MDA awarded approximately $482,000 in new research grants for mitochondrial myopathy.
MDA also supports multidisciplinary care through its nationwide network of MDA Care Centers. MDA families can contact the MDA Resource Center at 1-833-ASK-MDA1 (1-833-275-6321) or ResourceCenter@mdausa.org for guidance and support; media inquiries should be directed to press@mdausa.org.
Muscular Dystrophy Association (MDA) is the #1 voluntary health organization in the United States for people living with muscular dystrophy, ALS, and over 300 other neuromuscular conditions.MDA’s mission is to empower the people we serve to live longer, more independent lives.
Contact:
Mary Fiance, National Vice President, Strategic Communications Muscular Dystrophy Association press@mdausa.org
Paul Melmeyer, Executive Vice President, Public Policy and Advocacy at the Muscular Dystrophy Association
Art Estopinan, MDA family member and father of Arturito Estopinan
Olga Estopinan, MDA family member
Michio Hirano, MD, MDA Care Center Director and Professor of Neurology at Columbia University and Principal Investigator of the TK2d program
Source: Muscular Dystrophy Association
