The US Food and Drug Administration has approved Baxalta's long-acting haemophilia drug Adynovate for both treatment and prevention of bleeding episodes in adults and adolescents with Haemophilia A.

The drug has been modified to last longer in the blood and thus potentially require less frequent injections than unmodified antihaemophilic Factor when used to reduce the frequency of bleeding.

The move follows data from a pivotal Phase II/III study published back in August showing that Adynovate is better than its predecessor Advate, the world’s most prescribed factor VIII treatment, at clotting blood and preventing serious bleeds.

Patients in the twice-weekly prophylaxis arm of the trial experienced a 95% reduction in median annualised bleed rate versus those in the on-demand arm (1.9 versus 41.5, respectively), while the drug was also effective in treating all bleeding episodes, 95.9% of which were controlled with one or two infusions.

Safety signals also looked good, with no patients developing inhibitors to the drug or treatment-related serious adverse events, including hypersensitivity reactions.

Haemophilia A is an inherited, sex-linked, blood-clotting disorder that primarily affects males, caused by defects found in the Factor VIII gene. It is estimated to affect one in every 5,000 male births in the US, according to the Centers for Disease Control and Prevention.