Recruiting
Phase 2

KL1333

Sponsor:

Pharming Technologies B.V.

Code:

NCT07514338

Conditions

Mitochondrial Diseases

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

Napazimone

Study Details

Brief summary:

The purpose of this study is to investigate if the study medicine, KL1333, is safe, well-tolerated and effective long-term in improving the symptoms of fatigue and impacts on daily living and functional capacity (physical abilities) in people with PMD.

Conditions

Mitochondrial Diseases

Study ID

NCT07514338

Start date

Jun 12, 2026

Status verified date

Jul, 2026

Completion date

Mar 31, 2029

Anticipated

Primary completion date

Mar 31, 2029

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

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.

Study Design

Enrollment

140 participants

Anticipated

Intervention Model

Single group

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Open label extension

Subjects will receive medication twice a day for 48 weeks minimum

Interventions

Napazimone

Product: KL1333 (international nonproprietary name: napazimone) Dose: Each subject will be up-titrated to his/her maximum well tolerated dose. The starting dose will be 25 mg KL1333 twice daily (BID; total daily dose of 50 mg). If KL1333 is considered to be well tolerated after 4 weeks of treatment, the dose will be increased to 50 mg KL1333 BID (total daily dose of 100 mg). The dose may be lowered from 50 mg BID to 25 mg BID at the investigator's discretion throughout the study in case of tolerability issues.

Frequency: Twice daily Route: Oral

Primary outcome measure

  • Adverse events [ Time Frame: Through study at least for 48 weeks ]
  • Physical examination [ Time Frame: At Baseline Week 0, Week 4, Week 24 and Week 48 ]
  • Vital signs [ Time Frame: At Baseline Week 0, Week 4, Week 24 and Week 48 ]
  • Electrocardiogram [ Time Frame: At Baseline Week 0, Week 4, Week 24 and Week 48 ]
  • Safety laboratory - blood chemistry [ Time Frame: At Baseline Week 0, Week 4, Week 24 and Week 48 ]
  • Safety laboratory - urinalysis [ Time Frame: At Baseline Week 0, Week 4, Week 24 and Week 48 ]
  • Safety laboratory - hematology [ Time Frame: At Baseline Week 0, Week 4, Week 24 and Week 48 ]
  • Occurence of metabolic decompensation and lactic acidosis or image-verified stroke-like episodes consequent to GI AE and AESIs [ Time Frame: Through study at least for 48 weeks ]
  • Columbia Suicide Severity Rating Scale (C-SSRS) [ Time Frame: At Baseline Week 0 ]

Central Contacts and Locations

Central contacts

Audrey Simon, Sr. CPM

+31 71 524 7448a.simon@pharming.com

Locations

Akron Children's Hospital

Recruiting

Akron, Ohio, United States, 44308

Principal Investigator:

Bruce Cohen

More Information

Sponsor

Pharming Technologies B.V.

Last update posted

Sep 16, 2026

Last verified

Jul, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-18. This information was provided to ClinicalTrials.gov by Pharming Technologies B.V. on 2026-09-16.