The treatment landscape for hemophilia is changing fast, and today marks a turning point. The FDA has just cleared Roche to sell its drug emicizumab (Hemlibra) to patients with any form of hemophilia A—making it, potentially, the choice treatment for the disease. At least for now.
The FDA first approved emicizumab in late 2017 for the roughly 20 percent of hemophilia A patients with “inhibitors,” or immune responses that require the use of additional expensive drugs. Hemophilia affects an estimated 400,000 worldwide, and hemophilia A is the most common form of the disease. It is typically treated prophylactically with infusible drugs given multiple times a week that boost levels of the clotting proteins, or factors, these patients lack. These drugs help prevent dangerous bleeding events that can lead to joint damage and other health problems.
Since the FDA first approved emicizumab (an antibody drug given via subcutaneous injection), Roche and its South San Francisco, CA, subsidiary Genentech have been trying to expand the drug’s reach and prove it can be taken by more hemophilia A patients, and less frequently than other drugs.
Clinical studies named HAVEN-3 and HAVEN-4, presented at a medical meeting in May, have helped Roche’s case, showing that emicizumab may be effective at different dosing schedules—from once a week to once a month—and for hemophilia A patients without inhibitors. What’s more, in HAVEN-3, patients who switched from other preventative therapies before the study to weekly injections of emicizumab saw their bleeding rates cut by 68 percent, from an estimated 4.8 per year to 1.5 per year—the first time a hemophilia medicine was shown to significantly improve upon prophylaxis. That’s important, because Roche is trying to take market share from other hemophilia A drugs, among them Shire’s Feiba, which hemophilia A patients with inhibitors often have to take on top of other treatments to prevent bleeds. (Roche tried to undercut the competition by pricing the drug at $482,000 list price for the first year and $448,000 each year afterwards, a discount to Feiba.)
All told, there are big expectations for emicizumab. After Roche presented the HAVEN-3 and HAVEN-4 data in May, Jefferies analyst Ian Hilliker predicted emicizumab could now become the new standard of care for all hemophilia A patients and generate up to $5 billion a year at its peak.
But emicizumab has a long way to go—it generated just $58 million in the first half of 2018—and will have to shrug off safety concerns and looming competition. The FDA, for example, gave emicizumab a black box warning for severe blood clots, and in April, the nonprofit Hemophilia Federation of America reported in a letter that a total of five patients on emicizumab had died. (Genentech said none of the cases were related to its drug).
Additionally, an RNA interference treatment from Alnylam Pharmaceuticals (NASDAQ: ALNY), fitusiran, is in late-stage testing and could directly compete with emicizumab. The drug is also subcutaneous, taken monthly, and is cheaper to make than biologics. Then there’s gene therapy, which offers the chance for a one-time, long-lasting treatment. BioMarin Pharmaceutical (NASDAQ: BMRN) has a hemophilia gene therapy in late-stage testing, with results expected in 2019.