ZURICH (Reuters) - Roche’s patent dispute with London-listed Shire over the Swiss drugmaker’s new haemophilia drug Hemlibra has escalated, with Shire filing a new motion in a U.S. court that Roche says aims to stop some patients from getting its medicine.

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Shire’s motion for a preliminary injunction is part of an ongoing case in which it contends Roche infringed on a key patent to develop Hemlibra, approved in November by the U.S. Food and Drug Administration.

The patent dispute at the U.S. district court of Delaware underscores Hemlibra’s potential to take business from Shire, with some analysts estimating Roche’s roughly $450,000-per-year drug will hit $5 billion in annual sales by muscling in on older drugs for the genetic disease whose sufferers’ blood does not clot properly.

In a press release late last week, Shire said it expected a judge to rule next year.

“Until the court’s decision on the motion for the preliminary injunction, expected summer 2018, is made there will be no patient impact,” Shire said in a statement.

“Shire has proactively proposed a carve-out provision to facilitate access for patients, but the scope of the provision is ultimately a matter for the court to decide.”

There are about 20,000 people in the United States with the disease and 400,000 worldwide, according to the National Hemophilia Foundation.

In the patent dispute, Roche argues Shire’s patent is not valid and that its scientists did not encroach on its rival’s intellectual property.

On Saturday, the Swiss company acknowledged that Shire’s latest motion would have no immediate impact on the current situation in which Hemlibra is approved for so-called “inhibitor patients,” or those who have developed resistance to clotting treatments like those made by Shire.

“It will have to go through a formal legal process before a decision is made,” Roche said.

But it contends Shire’s motion seeks to encroach on decisions best left to doctors and patients. “We believe it is also inappropriate for Shire to dictate which patients should or should not receive Hemlibra,” the company said in a statement.

Roche is seeking to expand Hemlibra’s regulatory approvals beyond inhibitor patients to include those who have not yet developed resistance, to boost the medicine’s sales.

Shire, whose shares dropped on Nov. 20 after Hemlibra’s approval, contends its latest motion will protect patients by preserving their treatment options.

“The filing of the preliminary injunction is not a decision we made lightly, and we carefully considered the impact this filing may have on hemophilia patients,” it said.