The Boston-based Institute for Clinical and Economic Review (ICER), which has been reviewing Mayzent for months, recommended that Novartis lower the drug's price.

Novartis disputed the findings.

Mayzent was approved in March by the U.S. Food and Drug Administration for adults with relapsing forms of multiple sclerosis, including active secondary progressive disease (SPMS).

The FDA concluded oral Mayzent was not shown to be effective in forms of MS where relapses have stopped but the disease continues to progress, also known as non-active SPMS.

"It is unfortunate that Novartis chose a price that is so far out of line with (Mayzent's) benefits to patients with active SPMS, particularly with it entering a crowded field of disease modifying therapies," ICER Chief Medical Officer David Rind said in a statement late on Thursday.

Novartis said feedback and recommendations it gave to ICER were not taken into account, adding the U.S. group did not use the right comparisons to establish cost effectiveness of drug.

"Novartis believes that Mayzent brings value to MS patients," a company spokesman said, adding Mayzent had demonstrated a significant effect in delaying disability progression in a representative SPMS population.

The conclusions of ICER are used by insurers, pharmacy benefits managers and government agencies in the United States as they negotiate reimbursement for medicines with drugmakers.

Some patient groups funded by the drug industry have been critical of ICER's reports, saying the standards it uses to judge a drug's value are discriminatory.

(Reporting by John Miller, additional reporting by John Revill; Editing by Michael Shields)