Roche hemophilia drug hits mark in Phase 3

Dive Brief:

  • Roche on Thursday reported positive results from a pivotal Phase 3 study testing its experimental hemophilia drug emicizumab, which significantly reduced the number of bleeds in hemophilia A patients with inhibitors to factor VIII. 
  • The Swiss pharma also gave more details on four serious adverse events associated with emicizumab which had sparked concerns last month about the drugs prospects. Two patients were able to restart treatment. 
  • Hemophilia A affects around 320,000 people worldwide, and about 50-60% of these have a severe form of the disorder, according to Roche. A number of drugmakers are focusing on developing new drugs in the space, and prospects for some experimental gene therapies have grown.

Dive Insight:

Hemophilia A, an inherited bleeding disorder, is commonly treated with factor VIII replacement therapies. However, some patients develop antibodies against factor VIII, known as inhibitors, which impedes bleeding control. 

"The development of inhibitors that render factor VIII replacement less effective, or ineffective, is one of the greatest challenges in the treatment of hemophilia A today, putting patients at high risk for life-threatening bleeds and repeated bleeds that may cause long-term joint damage," said Sandra Horning, Roche's chief medical officer, in a statement

Among the four patients who experienced serious adverse events, two had thromboembolic events while the other two developed thrombotic microangiopathy. All four had received activated prothrombin complex concentrate to treat breakthough bleeds while on emicizumab prophylaxis, Roche said. 

One patient who had experienced a thromboembolic event and one of the patients with thrombotic microangiopathy were able to restart treatment. 

The safety events had dented some of the optimism around the drug, boosting the profile of rivals such as Alnylam Pharmaceutlcals' fitusiran. That drug is expected to move into Phase 3 trials in early 2017 and targets hemophilia B as well as the A subtype. 

Still, Roche's emicizumab is the most advanced and, if further data can ease concerns on safety, the drug should have a strong headstart. 

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Filed Under: Clinical Trials
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