UCB has received European Commission approval for Kygevvi, the first and only authorised treatment for thymidine kinase 2 deficiency, an ultra‑rare and life‑threatening mitochondrial condition marked by progressive muscle weakness.
The decision covers paediatric and adult patients with genetically confirmed TK2d whose symptoms began at or before age 12.
Announcing the approval, UCB said Kygevvi is a 2g/2g powder for oral solution and represents the first therapy available in the European Union beyond supportive care. The company noted that TK2d places a significant burden on patients and families due to its severe and progressive nature.
Donatello Crocetta, Chief Medical Officer at UCB, said: “The European Commission’s approval of KYGEVVI marks a historic milestone for the TK2d community. For the first time, people across Europe living with this ultra-rare, life-threatening mitochondrial disease have access to an approved treatment beyond supportive care.
“KYGEVVI is designed to support mitochondrial DNA maintenance in skeletal muscle, addressing a key biological driver of TK2d. We are deeply grateful to the patients, families, advocates, investigators, and clinical trial teams whose partnership, trust, and resilience made this achievement possible.”
Caterina Garone, Associate Professor of Medical Genetics at the University of Bologna, said: “TK2d has a profound impact on people living with the condition and their families and, until now, they have faced a heavy burden of unmet treatment need with incredible resilience. The TK2d community has waited a long time for this moment which brings them new hope and marks an important step forward in how clinicians can manage this devastating disease.”
The approval is supported by pooled data from two studies in patients with symptom onset at or before age 12. The trials assessed motor milestones, ventilatory and feeding support and survival. According to the data, Kygevvi was well tolerated, with the most common adverse reactions being diarrhoea, vomiting and abdominal pain.
Across the studies, 26 of 31 patients regained one or more motor milestones after starting treatment. Changes in ventilatory and feeding support also suggested clinical benefit, with some patients discontinuing support after initiation of therapy.
