A new extension study aims to evaluate the long-term safety of etranacogene dezaparvovec (CSL222) in male adults with hemophilia B who previously participated in studies CSL222_2001 (NCT03489291) or CSL222_3001 (NCT03569891). The study, sponsored by CSL Behring, is not yet recruiting.
The researchers plan to enroll approximately 56 adult male participants with hemophilia B who participated in one of the qualifying clinical trials. The participants will be followed up from year 5.5 after the single experimental drug infusion up to year 15. There are no exclusion criteria.
The researchers will analyze the number and percentage of participants with serious adverse events and adverse events of special interest as well as the number of serious adverse events and adverse events of special interest from year 5.5 after the experimental drug administration to year 15 as primary outcome measures.
The secondary outcome measures include the number of bleeding episodes, annualized bleeding rate, correlation analysis of annualized bleeding rate as a function of mean factor IX activity, percentage of resolution of target joins, EuroQol-5 Dimensions-5 level visual analog score overall score, as well as the number of participants with zero bleeds, new target joints, factor IX activity, those receiving factor IX replacement therapy, and remaining free of previous continuous routine factor IX prophylaxis.
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The study is scheduled to start in August 2023 and is estimated to last until March 2035.
Long-term follow-up study of male adults with hemophilia B previously treated with etranacogene dezaparvovec (CSL222). ClinicalTrials.gov. July 27, 2023. Last updated August 2, 2023. Accessed August 4, 2023.