IMP Welcomes FDA Approval of First-Ever Treatment for TK2d

International Mito Patient (IMP) is delighted to welcome yesterday’s approval by the U.S. Food and Drug Administration (FDA) of KYGEVVI® (doxecitine and doxribtimine) for the treatment of adults and children living with Thymidine Kinase 2 Deficiency (TK2d), with an age of symptom onset on or before 12 years.

This marks the first and only therapy approved for TK2d — an ultra-rare, life-threatening mitochondrial disease characterised by progressive muscle weakness and respiratory involvement.

This milestone follows another significant regulatory development earlier this year: the FDA’s approval of FORZINITY® (elamipretide) for people living with Barth syndrome, another rare mitochondrial disorder.

Together, these two approvals signify meaningful progress in mitochondrial medicine and offer renewed hope to families worldwide.

Paula Morandi, Chair of IMP, said: “This approval is nothing short of historic for the TK2d community. For those living with TK2d in the U.S., this therapy will be life-changing. Alongside the recent FDA approval of Forzinity for Barth syndrome, it clearly shows that research in mitochondrial diseases is moving forward and that treatments are possible.

I have seen first-hand how life changing KYGEVVI can be for patients. After taking KYGEVVI in the clinical trial, a patient who struggled to move on her own, is unrecognisable running and jumping and doing everything a little girl should. This drug has given her and her family their lives back. As patient groups we must continue to advocate for the development, approval and access to new therapies. IMP and our members represent mitochondrial disease patients around the world and we are relentless in our drive to ensure every patient receives the care they deserve.

We hope the FDA’s decision will pave the way for approval by the European Medicines Agency and other regulatory bodies globally.

We look forward to seeing more therapies being developed and approved for other types of mitochondrial diseases in the coming years. Every day, families battle with the devastating reality of mitochondrial diseases. Treatments — and ultimately cures — are so urgently needed. The approval of KYGEVVI and Forzinity gives real hope to the international mitochondrial disease community.”

For more information about KYGEVVI and how it may be used in the U.S., read UCB’s Press Release.

About TK2d

Thymidine Kinase 2 Deficiency (TK2d) is an ultra-rare and life-threatening genetic mitochondrial disease. It causes progressive and severe muscle weakness (myopathy), affecting mobility, breathing and other vital functions. When symptoms begin in early childhood, the condition is often rapidly fatal, with many children not surviving beyond a few years after onset. Until now, treatment options have been limited to supportive care only. TK2d is estimated to affect approximately 1–3 people per million worldwide.

Watch our short video about living with TK2d.

Forzinity
Read our article about the approval of Forzinity for Barth Syndrome.

About IMP
International Mito Patient (IMP) is the global alliance of patient organisations supporting individuals and families affected by mitochondrial diseases. IMP works to ensure the patient voice is represented in research, clinical care, policy, and regulatory decision-making, while driving international collaboration to accelerate the development of therapies and improve quality of life. For more information visit: www.mitopatients.org