Cladribine Tablets for the First-Line Treatment of Relapsing-Remitting Multiple Sclerosis: An Evidence Review Group Perspective of a NICE Single Technology Appraisal

Abstract

As part of the single technology appraisal process, the National Institute for Health and Care Excellence invited Merck to submit evidence for the clinical and cost effectiveness of cladribine tablets (cladribine) for the treatment of relapsing-remitting multiple sclerosis (RRMS). Rapidly evolving severe (RES) and sub-optimally treated (SOT) RRMS were specified by the National Institute for Health and Care Excellence as subgroups of interest. The Liverpool Reviews and Implementation Group at the University of Liverpool was the Evidence Review Group. This article summarises the Evidence Review Group's review of the company's evidence submission for cladribine and the Appraisal Committee's final decision. The final scope issued by the National Institute for Health and Care Excellence listed the following disease-modifying treatments as comparators: alemtuzumab, daclizumab, fingolimod and natalizumab. At the time of the company submission, a licence was anticipated for low-dose cladribine. The main clinical evidence (the CLARITY trial) in the company submission focused on the efficacy of low-dose cladribine vs. placebo. The CLARITY trial showed a statistically significant reduction in relapse rate for cladribine in the RES-RRMS subgroup (n = 50) but not in the SOT-RRMS subgroup (n = 19). Cladribine showed a numerical, but not a statistically significant, advantage in delaying disability progression at 6 months in the RES-RRMS subgroup. Disability progression benefits could not be estimated for those in the SOT-RRMS subgroup because of few events. The Evidence Review Group's main concern regarding the clinical evidence was the small sample size of the subgroups. To compare the effectiveness of cladribine to other disease-modifying treatments, the company conducted network meta-analyses, which showed cladribine and its comparators to be equally effective. The Evidence Review Group considered the results of the disease-modifying treatments to be unreliable because few trials were in the network. The company's cost-effectiveness evidence showed cladribine to be cheaper and more effective than other disease-modifying treatments in the RES-RRMS arm and the SOT-RRMS arm. The results were most sensitive to treatment effect on disability progression at 6 months. The Evidence Review Group was concerned that there was insufficient evidence to conclude that cladribine was superior to placebo in delaying disability progression. The Evidence Review Group amended the company's economic model to allow alternative estimates for the treatment effect of cladribine and its comparators on relapse rate and disability progression at 6 months. The Evidence Review Group made other changes to the company model. After implementing all the amendments, cladribine remained cost effective in the RES-RRMS and SOT-RRMS subgroups. The Appraisal Committee recognised the uncertainty in the available data but concluded that cladribine could be considered a cost-effective use of National Health Service resources.

Fig. 1

Health-state structure of the company model showing the ten Expanded Disability Status Scale (EDSS)-based health states while taking disease-modifying drugs (DMDs) or not taking DMDs. SPMS secondary progressive multiple sclerosis. Source: Company submission, Fig. 12