Roche's new hemophilia drug Hemlibra dramatically reduced bleeding in a broad population of hemophilia patients, results from two clinical trials showed on Monday, setting it up to take a dominant market position.

Hemlibra cut by 96 percent the incidence of treated bleeds in hemophilia A patients who did not get preventive treatment and compared with patients who did get preventive treatment in the form of clotting factors it reduced them by 68 percent.

The positive results from the two trials known as HAVEN 3 and 4 included so-called non-inhibitor patients. Hemlibra's initial success was in patients with inhibitors, which are antibodies that cause resistance to replacement clotting factors.

Hemlibra's current regulatory approval is only for these inhibitor patients but Roche plans to submit the latest findings to authorities around the world to widen its use.

While the drug's latest success had been expected, the positive results seen in a wide range of patients should underpin demand for a medicine that Roche is relying on as several of its blockbuster cancer drugs face cut-price rivals.

Jefferies analysts said HAVEN 4 also showed there was a potential to treat both inhibitor and non-inhibitor patients on only a once-monthly basis. Currently, Hemlibra is given as a once-weekly injection.

"This sets Hemlibra up to become the new standard of care for hemophilia A, which we view as a $5 billion peak sales opportunity," they said.

The current standard of care for people with hemophilia A without inhibitors is replacement factor VIII clotting factor.

Hemlibra will shake up the market and pose a threat to established players reliant on factor replacement therapies, notably Shire, which has agreed to be acquired by Takeda Pharmaceutical.

Also being challenged are Bayer, CSL, and Novo Nordisk, as well as Sanofi, which earlier this year bought U.S. hemophilia specialist Bioverativ.

New science also promises to bring further changes in the years ahead, with several companies working on hemophilia gene therapy, in which a harmless virus is used to introduce DNA to fix the faulty genes behind the disease, offering a possible one-off cure.

Data from the two Roche clinical studies were presented at the World Federation of Hemophilia congress in Glasgow, Scotland.

"With this data, we now have positive results from all four of our Phase III trials that reinforce the overall efficacy and safety of Hemlibra and its potential to improve care for all people with hemophilia A," said Roche Chief Medical Officer Sandra Horning.