Vertex Pharmaceuticals is considering a final offer from NHS England on funding for its cystic fibrosis therapies, but said it remains concerned that the deal on the table does not fully reflect the value of its existing and future medicines for the condition.

The offer, details of which were first revealed by Cystic Fibrosis Trust chief executive David Ramsden, who tweeted a letter he received from John Stewart, NHS England’s Director of Specialised Commissioning, would see NHS England pay Vertex around £500 million over the next five years and over £1 billion over the next 10 years for its existing and future CF therapies.

If accepted, the proposal would guarantee “immediate and expanded access” to Orkambi (lumacaftor/ivacaftor) and Kalydeco (ivacaftor), as well as Symdeco from the date it is licensed for use in the UK, Stewart wrote.

Also included is Vertex’ investigational next generation triple therapy, which is currently in advanced clinical trials but would become available on the NHS as soon as it is approved.

Commenting on the proposal, Ramsden said while the headline numbers look big, he remains “deeply concerned that they don't truly reflect the difference the pipeline of drugs will make.”

Also, a spokesperson for Vertex told BioCentury that NHS England's offer equates to about £14,000 per patient per year, which represents a near 90 percent discount on what Germany reimburses for Orkambi alone.

"We appreciate NHS England’s counter-offer and hope it signals a willingness to re-engage in discussions to reach our collective goal of providing access to our CF medicines for patients,” Vertex said in a short statement.

“While we are evaluating the proposal, we share the CF community’s concerns that this proposal fails to adequately reflect the value of our current and future medicines – and the number of patients that will be treated with these medicines – and stand ready to meet to find a productive path forward.”

Orkambi is the first drug for CF directed at treating the cause of the disease in people who have two copies of the F508del mutation, accounting for around 45 percent of cases.

Data from the Phase III TRAFFIC and TRANSPORT studies show that the therapy significantly improved lung function (as measured by FEV1) by 2.6-4.0 percent, and reduced the rate of pulmonary exacerbations by 30-39 percent in target CF patients.

According to NHS England, its proposal would see the number of patients receiving effective therapies that address the genetic causes of CF rise from 450 to 5,000 this year with further expansion in coming years.

“NICE will assess these medicines in the usual way, but under the terms of the proposal patients will not have to wait for the outcome of these appraisals before access begins,” it said.