The European Medicines Agency (EMA) has recommended granting a conditional marketing authorisation for Durveqtix (fidanacogene elaparvovec) in the European Union (EU) to treat severe and moderately severe haemophilia B in adults without factor IX inhibitors and no detectable antibodies to variant adeno-associated virus serotype Rh74 (AAVRh74var). This groundbreaking gene therapy is delivered as a single infusion and aims to enable the body to produce factor IX, thereby preventing and controlling bleeding episodes.
Haemophilia B is a rare inherited bleeding disorder caused by the lack of coagulation factor IX, essential for blood clot formation. Patients with this condition bruise easily, bleed more frequently, and suffer prolonged bleeding episodes, which can lead to serious complications like bleeding in joints, muscles, or internal organs, including the brain. Current treatments require frequent and lifelong intravenous infusions, highlighting the need for new therapies that offer sustained bleed protection and reduce infusion frequency, thereby improving patients’ quality of life.
The EMA’s recommendation is based on an ongoing single-arm, open-label, phase 3 trial involving 45 adult male patients with moderately severe or severe haemophilia B. These patients, who tested negative for neutralising antibodies to AAVRh74var, received a single intravenous infusion of Durveqtix. The study compared the annualised bleeding rate (ABR) of participants treated with gene therapy against their previous routine factor IX prophylaxis regimen.
Durveqtix Significantly Reduces Bleeding in Haemophilia B Patients
Results showed that Durveqtix substantially reduced the frequency of bleeding compared to standard care. The ABR was 1.44 for Durveqtix versus 4.50 for prophylaxis treatment. Additionally, 60% of patients treated with Durveqtix remained without a bleeding event during the observation period (ranging from two to four years) compared to 29% during the lead-in period on routine prophylaxis. Furthermore, the consumption of prophylactic factor IX was reduced by 92.4% after treatment with Durveqtix.
Patients treated with Durveqtix will be followed up for 15 years, including six years in the pivotal clinical trial and an additional nine years in a separate study to monitor long-term efficacy and safety. The most common side effect observed was an increase in liver enzyme levels (transaminases), treatable with corticosteroids. Other common side effects included headache, flu-like symptoms, increased creatinine levels (indicative of impaired kidney function), and elevated lactate dehydrogenase levels (indicative of tissue damage). Patients should be monitored for infusion-related reactions.
EMA’s PRIME Scheme Supports Approval of Durveqtix for Haemophilia B
Durveqtix received support through EMA’s PRIority MEdicines (PRIME) scheme, which provides early and enhanced scientific and regulatory support for medicines with the potential to address unmet medical needs. The Committee for Advanced Therapies (CAT), EMA’s expert committee for cell- and gene-based medicines, concluded that the benefits of Durveqtix outweighed the possible risks for patients with haemophilia B. The CHMP, EMA’s human medicines committee, concurred with CAT’s assessment and recommended the approval of Durveqtix.
The CHMP’s positive opinion is an intermediary step towards making Durveqtix available to patients. The opinion will now be sent to the European Commission for the adoption of a decision on an EU-wide marketing authorization. Once granted, decisions about pricing and reimbursement will be made by individual EU Member States, considering the potential role of Durveqtix within their national health systems.
The applicant for Durveqtix is Pfizer Europe MA EEIG. Durveqtix was granted eligibility to PRIME on 23 February 2017 for the treatment of severe haemophilia B. This development represents a significant advancement in the treatment of haemophilia B, offering hope for improved patient outcomes through innovative gene therapy.
Resource: European Medicines Agency, May 31, 2024
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