Maraviroc (Celsentri) has been rejected for NHS use in Scotland. The Scottish Medicines Consortium found that its makers, Pfizer, “did not present a sufficiently robust economic analysis to gain acceptance”.
Formal European marketing approval for maraviroc was granted in September 2007. It is currently the only approved CCR-5 inhibitor. Approval of maraviroc was based upon the MOTIVATE studies which showed that its use, in combination with other antiretrovirals selected after resistance testing, increased the chances of heavily pre-treated patients with drug resistance achieving an undetectable viral load.
Maraviroc is an option for patients with drug-resistant HIV who have CCR-5 tropic virus. Not all individuals with drug resistance have this type of virus, and before commencing therapy with maraviroc it is necessary for patients to first have a tropism test, the cost of which is currently subsidised by Pfizer.
British HIV treatment guidelines, updated this year, include recommendations on the use of maraviroc in treatment-experienced patients.
The Scottish Medicines Consortium noted the evidence from clinical trials showing improved virological outcomes in heavily pre-treated patients who received maraviroc. But they raised four specific objections to Pfizer’s economic case for maraviroc approval.
- Uncertainty about the cost and effects of other drugs that need to be taken with maraviroc to construct an effective antiretroviral combination.
- Reliance on a dated paper for the costs of antiretroviral drugs other than maraviroc and T-20 (enfuvirtide, Fuzeon).
- Mortality figures submitted by Pfizer came from older papers “and may not reflect what might be expected in the Scottish population.”
- General lack of clarity in the cost-effectiveness figures submitted.
“Given these issues, the manufacturer has not presented a sufficiently robust economic case for acceptance”, notes the decision.
Pfizer advised the Scottish Medicines Consortium that it would expect 50 Scottish patients in the first year to require therapy with maraviroc, the number increasing to 84 individuals after five years.
But the decision of the Scottish Medicines Consortium notes that their own “experts suggest that the number of patients likely to receive maraviroc is less than the manufacturer suggests”.