A four-day hearing got under way today that may decide how the UK’s National Institute for Health and Clinical Excellence decides how it will cover medicines. Pfizer and Eisai hope to force the National Health Service to give all Alzheimer’s patients access to Aricept, which they market jointly. The NICE recommended last year the drug shouldn’t be prescribed for patients with early stage Alzheimer’s.

In explaining their decision, NICE officials said Aricept wasn’t cost effective at $5 a day, and so recommended use only for patients with moderate-stage Alzheimer’s. “The reality is that, for Alzheimer’s disease, drugs are only part of the care that needs to be offered,” Andrew Dillon, NICE’s chief executive, tells the Associated Press. “Non-drug interventions have an important part to play and the evidence indicates that drugs are simply not effective for some patients.”

The drugmakers and the Alzheimer’s Society accuse NICE of telling patients they must get worse before they can be treated. “These treatments have benefited so many families already,” says Neil Hunt, chief executive of the Alzheimer’s society. “Where is the justice in NICE’s decision to snatch them away?”

The outcome of the lawsuit may influence how the UK’s National Health Service decides which medicines are covered by its $24 billion budget. A victory “may have a substantial influence over the future boldness of NICE in conducting an effective rationing policy,” David Lock, a lawyer who head the health-care practice at UK law firm of Mills & Reeve, tells Bloomberg News.

This is also believed to be one of the first cases to challenge the fairness of underlying economic modelling used for cost-benefit analysis, and the first in the healthcare field in the IK. “It’s never been done before in the health context, as far as I’m aware - this case is very, very novel in many ways,” John Halford at Bindman & Partners, the law firm advising the Alzheimer’s Society, tells The Financial Times.