By Tamara Mathias and Caroline Humer

(Reuters) – BioMarin Pharmaceutical Inc said on Tuesday early trial data for its gene therapy for hemophilia A suggested the one-time infusion’s effect on some patients’ bleeding disorders would last eight years.

The gene therapy, called valoctocogene roxaparvovec, is one of several gene therapies under development that have been raised as “one-and-done” potential cures that could be worth price tags of more than $1 million.

BioMarin said it had extrapolated the forecast from patient data culled from a study that has followed eight patients for three years. It also released data from a second trial on 17 patients who have been followed for about six months so far.

The treatment aims to enable patients with hemophilia A to make the blood-clotting protein they otherwise lack.

Based on the study data, the company said the treatment’s impact wanes at first, then plateaus in the second year before declining more slowly over time but remains effective for up to eight years. The company said over time, it may find that the treatment lasts longer.

On Tuesday when it released the data update, the company said it was researching how to give patients a second dose of the treatment if its impact wanes.

In addition, some patients in the trial received doses of the clotting protein that patients with hemophilia A lack — factor VIII — in order to avoid the painful bleeding in muscles and joints that is typical of the condition.

Many hemophilia patients receive these clotting protein infusions several times a week in order to try to avoid bleeding. One patient in the study resumed these regular infusions, BioMarin said.

Shares of the company closed down 5% to $84.50.

The data “update indicates durable benefit beyond 3 years for most patients, but doesn’t seem to have the legs to look like a true ‘cure,’” Evercore ISI analyst Josh Schimmer said in a research note.

The company said the data showed a dramatic reduction in patient need for protein infusions.


BioMarin Chief Executive Officer Jean-Jacques Bienaime said that based on the cost of five years of treatment for the current standard of care, the value of BioMarin’s gene therapy could be $2 million. Treatments to replace blooding-clotting proteins cost about $400,000 per year, he said.

Last week, Swiss drugmaker Novartis AG priced its one-time gene therapy for spinal muscular atrophy at $2.1 million, the highest price ever for a drug. The price was based on the five-year cost for its rival treatment, Biogen’s Spinraza, Bienaime noted.

(Reporting by Caroline Humer in New York and Tamara Mathias in Bengaluru; Editing by Leslie Adler)