Roche Holding AG said the U.S. Food and Drug Administration approved Hemlibra to treat a bleeding disorder known as hemophilia A in patients who have developed a resistance to a certain blood clotting therapy.

Hemophilia A is an inherited disorder in which a person's blood does not clot properly due to lack or shortage of a clotting protein called factor VIII. The treatment for the disorder may involve a complication in which the body's immune system develops antibodies, or inhibitors, that block therapies to replace factor VIII.

The therapy, also called emicizumab-kxwh, is being co-developed globally by the Swiss drugmaker and its majority-owned Japanese unit Chugai Pharmaceutical Co. Ltd. It was approved by the U.S. FDA in November 2017 to treat patients with hemophilia A with factor VIII inhibitors.

Roche said Hemlibra is now the only preventive treatment for hemophilia A among patients with and without factor VIII inhibitors that can be delivered through the skin in multiple doses.

The approval is based on two phase 3 studies, with a study named Haven 3 showing that Hemlibra led to statistically significant reductions in treating bleeds when compared to an absence of a preventive treatment. The other study named Haven 4 demonstrated that Hemlibra showed clinically meaningful control of bleeding in patients who were previously treated with other therapies.

Roche said the European Medicines Agency is reviewing a similar application for Hemlibra, with submission underway to other regulatory authorities.