Open-label extension to test KL1333 long-term safety and benefit for primary mitochondrial disease

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This is a 12-month open-label extension of a prior KL1333 trial to assess long-term safety, tolerability, and efficacy in people with primary mitochondrial disease. Participants either retreat with KL1333 or start it if previously on placebo, with a 48-week treatment period followed by a short completion and follow-up. Safety monitoring continues regularly, including phone visits every 4 weeks and in-clinic visits every 24 weeks. The study allows for extended treatment if the drug remains available, with ongoing safety assessments and patient-reported outcomes. Eligibility requires prior completion of the parent study and ability to adhere to visits and procedures.

Why it matters

Who can join: the full rules

Inclusion Criteria:

* Completed the FALCON study (age 18 years or older), and in the opinion of the investigator and sponsor has been compliant with the study requirements
* Willingness and ability to attend study appointments within the specified time windows
* Willingness and ability to complete electronic patient-reported outcomes
* Concomitant medications likely to remain stable throughout participation in the study where clinically possible
* Willingness to suspend treatment with idebenone during the study

Exclusion Criteria:

* The subject is, in the investigator's opinion, unlikely to comply with the protocol, e.g., due to cognitive impairment, or is unsuitable for any reason.
* Any medical, psychiatric, laboratory or other condition that may negatively affect the benefit-risk considerations of study participation or interfere with the interpretation of study results and, in the judgment of the investigator and/or the medical monitor, would make the subject inappropriate for entry into this study.

Subjects not enrolling directly at the FALCON study completion visit (FALCON Week 48) or the safety follow-up visit (FALCON Week 53) study will be required to fulfill the additional exclusion criteria below during the screening visit:

• General fatigue or muscle weakness due to causes other than mitochondrial disease, in the opinion of the investigator.

Where it's running

• Akron Children's Hospital
  Akron, Ohio, United States Recruiting
• Hospital Erasme
  Brussels, Belgium Recruiting
• Hopital Universitaire de Bruxelles (H.U.B)/ Academisch Ziekenhuis Brussel
  Brussels, Belgium Recruiting
• University Hospital
  Ghent, Belgium Recruiting
• Universitair Ziekenhuis Gent
  Ghent, Belgium Recruiting
• University Hospital
  Leuven, Belgium Recruiting

Study contacts

• Study coordinator: Audrey Simon, Sr. CPM
• Email: a.simon@pharming.com
• Phone: +31 71 524 7448

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.