BioMarin’s hemophilia gene therapy recommended for approval in Europe

The regulatory agency that recommends whether new drugs should be approved in Europe has thrown its support behind a gene therapy for the rare bleeding disorder hemophilia A, putting the potentially curative treatment one step closer to market.

People with hemophilia A have genetic mutations which impair their ability to make a blood-clotting protein called Factor VIII. They are therefore more likely to experience prolonged or even life-threatening bleeds. Most of the drugs currently used to treat hemophilia A contain engineered versions of Factor VIII, and are administered two to three times a week.

Pharmaceutical firms and healthcare authorities like the European Medicines Agency see a demand for new treatment options that can be given less frequently and, as such, are more convenient for patients. Hemlibra is a different kind of hemophilia A drug that’s administered once weekly and, for some patients, once monthly, for example. Since gaining approval in the U.S. in 2017 and Europe in 2018, Hemlibra has become a multibillion-dollar product for its maker, Roche.

Another closely watched treatment is the gene therapy that now has the EMA’s backing. If approved by the European Commission, the therapy, known as Roctavian, would be the first commercially available genetic medicine for hemophilia A.

Developed by BioMarin, a California-based biotechnology company, Roctavian uses an engineered virus to shuttle the gene for making Factor VIII into liver cells, where it can then produce the vital protein. Data released early this year — from the largest ever study of a hemophilia gene therapy — show that patients with severe hemophilia A who were treated with Roctavian experienced few, if any, bleeds over a two-year study period.

Across 112 patients, the average number of annual bleeding events went from close to five before the study started to less than one in the two years since they received Roctavian. Treatment also reduced the average Factor VIII infusions these patients needed by 98%, according to BioMarin.

Additionally, the average number of annual bleeding events was also less than one in a subgroup of 17 patients who had been followed for at least three years post-treatment. Five- and six-year data from a smaller, earlier study were disclosed last month.

While Factor VIII levels spiked in the initial months after Roctavian treatment, the data collected thus far suggests they decline over time. BioMarin executives have maintained that the treatment should still offer at least five years of bleeding control. On a broader level, though, drug regulators have raised concerns about how long gene therapies can remain effective in the body.

“Longer-term follow-up tests may be required to verify a continued safe and effective response to the medicine,” the EMA said in a statement on Roctavian.

The agency added that its approval recommendation was based on results from BioMarin’s larger study. BioMarin, meanwhile, expects a final verdict from the European Commission sometime between July and the end of September.

The recommendation “offers hope for a new treatment option for people with severe hemophilia A, who have been bound to lifelong treatment and still experience serious health complications,” Johannes Oldenburg, director of the Institute of Experimental Haematology and Transfusion Medicine and the Haemophilia Centre at the University Clinic in Bonn, Germany, said in a statement from BioMarin.

“The robust data set from the clinical trial program underscores the potential impact of gene therapy for patients, including a substantial and sustained reduction in bleeding that would have previously required Factor VIII infusions,” Oldenburg added.

The EMA’s nod comes almost two years after the FDA rejected Roctavian in a decision that surprised BioMarin as well as Wall Street analysts. According to company, the agency wanted two years of follow-up data from every patient in that large study — a requirement which couldn’t be met until late 2021 at the earliest.

To BioMarin, the results released in January offer further supportive evidence and another shot at U.S. approval. “I believe that these results will answer, quantitatively, quite a lot of the questions that agencies have had,” Hank Fuchs, BioMarin’s head of research and development, said on a company conference call at the time.

The company had planned to resubmit its Roctavian application to the FDA by the end of June, but now expects to file in September due to “additional information” it said the FDA asked to be included.

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