KL1333 OLE for Primary Mitochondrial Disease

• Research type

  Research Study

• Full title

  An open-label, single-arm extension study to evaluate the long-term safety, tolerability, and efficacy of KL1333 (napazimone) in patients with primary mitochondrial disease

• IRAS ID

  1013832

• Contact name

  Rahma Saleh

• Contact email

  iconregulatoryaffairs@iconplc.com

• Sponsor organisation

  Pharming Technologies B.V.

• Eudract number

  2025-524367-20

• Clinicaltrials.gov Identifier

  NCT07514338

• Research summary

  This clinical study is a 12 month open label extension (OLE) of the FALCON study (KL1333 2020 104A). Its purpose is to further evaluate the long term safety, tolerability, and potential benefits of KL1333 (napazimone) in adults with primary mitochondrial disease (PMD).

  Who Can Participate
  Adults aged 18 years or older who completed the 48 week FALCON study are eligible. Participants must be able and willing to attend study visits, complete electronic questionnaires, maintain stable medication where possible, and comply with study requirements.

  How Enrollment Works
  Participants may join the extension study directly at the FALCON Week 48 or Week 53 visits or later in time.

  Study Design and Treatment
  This is an open label study, meaning all participants will receive KL1333 and the participants and study staff will know that KL1333 is being given; there is no placebo group.
  It will consist of a Screening and enrolment visit, a 48 week treatment period, an End of treatment visit and an End of Study visit. During the treatment period, there will be alternating visits at the clinical site and phone calls. There may be an optional extended treatment period.

  Dosing
  All participants will receive KL1333 orally twice daily with a daily dose between 50 and 100 mg.

  Study Objectives and Endpoints
  1. Safety and Tolerability will be assessed through Adverse events, Physical examinations, Safety laboratory tests (blood and urine) and questionnaires
  2. Efficacy will be assessed through the 30-second Sit-to-Stand test, questionnaires for fatigue symptoms, physical function, activities of daily living, and health related quality of life, as well as an assessment of overall progression of mitochondrial disease

  Number of Participants
  Approximately 100 to 180 adults are expected to enroll. The final number will depend on how many participants complete the FALCON study.

• REC name

  East of England - Cambridge Central Research Ethics Committee

• REC reference

  26/EE/0118

• Date of REC Opinion

  23 Jun 2026

• REC opinion

  Further Information Favourable Opinion