FILE PHOTO: A sign marks a Biogen facility in Cambridge, Massachusetts, U.S. January 26, 2017. REUTERS/Brian Snyder/File Photo

LONDON (Reuters) - Biogen’s muscle disease treatment Spinraza has been deemed too expensive for use on Britain’s state-run health service, even after a price discount offered by the U.S. drugmaker.

Spinraza, which has a U.S. list price of $750,000 in the first year of treatment, is a big money-spinner in Biogen’s home market. But Britain’s healthcare cost agency NICE said on Tuesday it could not recommend it as a cost effective treatment.

That is despite Spinraza, which is also known as nusinersen, having a lower British price tag of 450,000 pounds ($573,000) for the first year and Biogen offering an undisclosed discount to the National Health Service (NHS).

“Even with the proposed confidential discount the cost of nusinersen is too high for it to be considered a cost-effective use of NHS resources,” the National Institute for Health and Care Excellence (NICE) said.

NICE’s committee of experts also raised concerns that there were still significant uncertainties around the long-term benefits of the medicine.

“We are actively engaging with Biogen to discuss how they might address the uncertainties identified by the committee, while demonstrating the potential for nusinersen to be considered cost effective and managing the risk to the NHS of allowing access to this treatment,” said Meindert Boysen, NICE’s health technology evaluation director.

Spinraza is the first approved treatment for the rare and often fatal disease spinal muscular atrophy or SMA.