Pharma, BioPharma

FDA lifts clinical hold, clearing uniQure to resume hemophilia gene therapy trial

A uniQure gene therapy for hemophilia B that has been under a clinical hold for four months can now resume testing. The hold was lifted after uniQure answered the FDA's questions about whether the gene therapy caused the liver cancer diagnosed in one patient who received the therapy.

 

A uniQure gene therapy clinical trial that has was halted late last year now has regulatory clearance to resume. The Netherlands-based company announced Monday that the FDA lifted the clinical hold on etranacogene dezaparvovec, the company’s experimental gene therapy for hemophilia B. The hold was placed after one patient who had received the therapy two years earlier was diagnosed with a form of liver cancer.

Cancer is a known risk of gene therapies, which use an engineered virus to ferry a genetic payload into cells. If that virus integrates with a patient’s DNA, it can cause cancer. Last month, uniQure reported results of an independent investigation that concluded gene therapy was “highly unlikely” to be the cause of the cancer in the patient who received the uniQure treatment.

According to the company, the independent analysis found that integration of the virus into the patient’s tissues was rare. Also, the patient in question patient had multiple risk factors, including a twenty-five-year history of hepatitis C and a history of hepatitis B—both of which have been associated with liver cancer.

Patients who have hemophilia B have a mutation in the gene that codes for the clotting factor IX (FIX). The uniQure gene therapy uses adeno-associated virus type 5 (AAV5) to carry a functioning version of the FIX gene to patient’s cells. UniQure had been testing its gene therapy in an open-label, pivotal study that enrolled 54 patients, each of whom received a single infusion of the one-time treatment. The main goal is to assess FIX activity 26 weeks after dosing. The secondary goal is to assess annualized bleeding rates at 52 weeks.

With the clinical hold now resolved, Ricardo Dolmetsch, president of research and development at the Amsterdam-based company, said in a prepared statement that preliminary 52-week data for the gene therapy are expected later in the current quarter.

In the more than 100 participants in uniQure’s gene therapy studies, no other patients have been diagnosed with cancer. UniQure said that all patients in the study have had abdominal ultrasounds performed at the one-year mark following dosing. Each of them will continue to be monitored, receiving abdominal ultrasounds every six months.

Rights to the uniQure hemophilia B gene therapy were licensed to CSL Behring last year for $450 million up front. According to the deal terms, uniQure is responsible for completing the Phase 3 studies and submitting the gene therapy to the FDA for review. CSL Behring will reimburse uniQure for those expenses, and if the therapy reaches the market, it has also agreed to pay up to $1.6 billion in regulatory and commercialization milestones, plus royalties from sales.

Photo: virusowy, Getty Images

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