By VETTAPHARMA reporter: Amsterdam, Netherlands, February 2026 — The European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use (CHMP) has adopted a positive opinion recommending marketing authorization for Kygevvi® (doxecitine and doxribtimine) as a treatment for thymidine kinase 2 deficiency (TK2d), an ultra-rare, life-threatening mitochondrial genetic disease with no authorized therapies currently available in the EU. This recommendation marks a significant milestone toward providing the first approved treatment option for this condition in Europe.
Kygevvi was supported through the EMA’s PRIority MEdicines (PRIME) scheme, which offers enhanced scientific and regulatory guidance for medicines addressing unmet medical needs. If approved, Kygevvi would become the first and only authorized therapy for TK2d in the European Union, offering new hope to patients, families, and clinicians dealing with this devastating disease.
TK2d is caused by mutations in the thymidine kinase 2 (TK2) gene, which impairs the TK2 enzyme’s ability to support mitochondrial DNA production and maintenance, leading to progressive myopathy (muscle weakness), loss of motor function, breathing difficulty, and shortened life expectancy. The disease affects fewer than 1 in 1,000,000 people, with symptom onset often occurring in early childhood. Current care in Europe is limited to supportive measures such as feeding tubes, physiotherapy, and mechanical ventilation.
The CHMP’s positive opinion for Kygevvi was based on data from two pooled clinical studies involving patients whose disease began at or before 12 years of age. The treatment’s active components, the pyrimidine nucleosides doxecitine and doxribtimine, are believed to be incorporated into mitochondrial DNA in muscle cells, helping to restore mitochondrial DNA copy number and improve skeletal muscle function. The studies assessed motor milestones, ventilatory support, and feeding support before and after treatment, and also compared survival outcomes to external control groups.
In the studies, patients receiving Kygevvi showed functional improvements, including retained or regained motor milestones and stabilization of ventilatory and feeding support needs. The most common side effects associated with treatment were gastrointestinal disorders, such as diarrhea, vomiting, and abdominal pain.
The EMA’s recommendation was issued under exceptional circumstances, a regulatory pathway used when full efficacy and safety data cannot be obtained due to the extreme rarity of the condition. As part of this process, the CHMP has requested additional studies to further confirm the treatment’s safety and efficacy post-authorization. The positive opinion will now be forwarded to the European Commission, which will make a final decision on an EU-wide marketing authorization. After that decision, individual EU Member States will determine pricing and reimbursement while considering national health system contexts.
Source credit:
- European Medicines Agency. (2026, January 30). First treatment for rare thymidine kinase 2 deficiency. Click here
Disclaimer:
The contents published on this platform are intended solely for informational and educational purposes. Reports, summaries, and discussions related to clinical trials are based on publicly available data, press releases, scientific publications, and regulatory disclosures available at the time of reporting. The information provided does not constitute medical advice, diagnosis, treatment recommendations, or endorsement of any drug, therapy, or clinical outcome. Clinical trial data are subject to change as studies progress, and results discussed may be preliminary, incomplete, or not yet peer-reviewed. Readers are strongly encouraged to refer to the original clinical trial records, regulatory filings, peer-reviewed articles or related sources for complete, accurate, and up-to-date information. Healthcare professionals and patients should consult qualified medical professionals and relevant regulatory authorities before making any healthcare or treatment decisions. Images used on this platform are illustrative in nature and are intended for conceptual and representational purposes only. They may not depict actual products, facilities, individuals, or events. The platform and its contributors disclaim any liability for actions taken based on the information presented.
