A potential one-shot-and-you’re-done hemophilia A treatment from BioMarin Pharmaceutical Inc. will target regulatory approval in the United States and Europe after showing dramatic decreases in bleeding during clinical trials.
But in a competitive market to find the next big and expensive treatment to help — or even cure — hemophilia A patients, questions linger around how long the treatment sticks with patients. BioMarin (NASDAQ: BMRN) apparently didn’t allay those concerns Tuesday: The San Rafael-based company said its treatment appeared to plateau in restoring the amount of a clotting protein, known as Factor VIII.
The so-called durability of BioMarin’s valoctocogene roxaparvovec — or “valrox,” for short — could have an impact on the treatment’s ultimate acceptance by patients and what the company can charge for it. Just last week, Novartis AG said it would charge $2.1 million for a gene therapy to treat a muscle-wasting disease known as spinal muscular atrophy.
BioMarin stock closed down $4.57 per share, or 5.1 percent, to $84.50 in Tuesday trading.
On the surface, BioMarin’s disclosures around valrox Tuesday are positive. The company said a late-stage clinical trial found that eight patients met pre-specified criteria for Factor VIII activity levels. That study and a Phase I/II study dropped the median number of annual bleeding events to zero after three years, and the company thinks valrox could hit the market by the end of 2020.
The drop in the number of bleeding events is significant, both from a statistical point of view and for patients. Hemophilia A, also known as “classic hemophilia,” is a genetic disorder that causes the body to produce little or no Factor VIII. Without the clotting protein, minor cuts can turn into life-threatening bleeds and bruising can cause blood to pool around and damage joints and muscles.
There are about 20,000 people in the United States with hemophilia A, according to the National Hemophilia Foundation, and some patients in the earlier-stage study had a median of 16.3 bleeding events in the year before entering the study; valrox brought that to virtually zero.
“These data confirm that valoctocogene roxaparvovec has the potential to profoundly impact the lives of people with severe hemophilia A through a sustained reduction in bleeds and Factor VIII usage,” Dr. Hank Fuchs, BioMarin’s president of global research and development, said in a statement Tuesday.
BioMarin is led by Chairman and CEO Jean-Jacques Bienaimé.
Hank Fuchs is BioMarin’s president of global research and development.
Today, many hemophilia patients are largely dependent on injections several times a week of drugs, including ones manufactured at Bayer’s Berkeley facility, to maintain Factor VIII levels. Those treatments can cost upwards of $1,000 a week.
The promise of gene therapy — in hemophilia as well as other genetic diseases — is ultimately to provide more than a patch but a long-term fix, even a cure, with a single treatment. While valrox caused bleeding control to plateau at three years, Fuchs said that statistical models indicate the effect should last for at least eight years.
“This is fantastic news for the hemophilia community,” Fuchs said.
Wall Street saw the durability of valrox as significant, particularly in a hemophilia drug development marketplace that has spotlighted a handful of Bay Area companies. Another experimental gene therapy from Richmond’s Sangamo Therapeutics Inc. (NASDAQ: SGMO) and partner Pfizer Inc. (NYSE: PFE), called SB-525, last month showed zero bleeding events and a dose-dependent increase in Factor VIII levels across four different dosing groups with two people each.
Then there is Bayer, which won FDA and European regulatory approval last year for a long-acting Factor VIII treatment, and South San Francisco’s Genentech Inc., which in fall 2017 won regulatory approval of Hemlibra, a treatment injected just once a week.