Golimumab per il trattamento dell’artrite psoriasica

Abstract

The National Institute for Health and Clinical Excellence (NICE) invited the manufacturer of golimumab (Schering-Plough/Centocor) to submit evidence for the clinical and cost effectiveness of this drug for the treatment of active and progressive psoriatic arthritis (PsA) in patients who have responded inadequately to previous disease-modifying anti-rheumatic drugs (DMARDs). The Centre for Reviews and Dissemination and the Centre for Health Economics at the University of York were commissioned to act as the Evidence Review Group (ERG) to critically appraise the evidence presented by the manufacturer. This article provides a description of the company submission, the ERG review and the resulting NICE guidance. The ERG critically reviewed the evidence presented in the manufacturer’s submission and identified areas requiring clarification, for which the manufacturer provided additional evidence.

The main clinical effectiveness data were derived from a single phase III randomized controlled trial (GO-REVEAL) that compared golimumab with placebo for the treatment of active and progressive patients who were symptomatic despite the use of previous DMARDs or NSAIDs. The 14-week data showed that, compared with placebo, golimumab 50 mg significantly improved joint disease response as measured by American College of Rheumatology (ACR) 20 (relative risk [RR] 5.73, 95% CI 3.24, 10.56) and Psoriatic Arthritis Response Criteria (PsARC) [RR 3.45, 95% CI 2.49, 4.87], and significantly improved skin disease response as measured by Psoriasis Area and Severity Index (PASI) 75 (RR 15.95, 95% CI 4.62, 59.11). The 24-week absolute data showed that these treatment benefits were maintained. There was a significant improvement in patients’ functional status as measured by Health Assessment Questionnaire change from baseline at 24 weeks (−0.33;p<0.001). The open-label extension data showed that these beneficial effects were also maintained at 52 and 104 weeks. The ERG identified several issues relating to the clinical effectiveness results. Analyses of the 24-week data were less robust, failing to adjust for treatment contamination due to patient crossover at week 16. It was also unclear if these results were generalizable to clinical practice.

No randomized controlled trial compared the effectiveness of different biologic therapies head-to-head. To compare the effectiveness of the biologics etanercept, infliximab, adalimumab and golimumab, the manufacturer conducted a network meta-analysis, including the comparator palliative care (usual care including use of NSAIDs or DMARDs). The ERG considered the assumption of exchangeability between the trials for the purpose of the network meta-analysis to be acceptable and the statistical approach to be reliable. The results indicated somewhat lower efficacy with golimumab than with comparator biologics.

The ERG identified a number of issues relating to the cost-effectiveness results. The manufacturer calculated incremental cost-effectiveness ratios (ICERs) incorrectly by comparing golimumab with palliative care instead of the most cost-effective alternative (etanercept). Despite the manufacturer’s claim that golimumab was a cost-effective treatment option, the manufacturer’s own model showed that golimumab was unlikely to be cost effective, relative to currently accepted thresholds, when the ICERs were correctly calculated using an incremental analysis (i.e. comparing each treatment to the next best alternative). None of the sensitivity analyses carried out by the manufacturer or the ERG regarding uncertainty in the estimates of clinical effectiveness, the acquisition and administration cost of drugs, the cost of treating psoriasis and the utility functions estimated to generate health outcomes changed this conclusion.

However, a key area in determining the cost effectiveness of biologics was whether they should be treated as a class. The ERG concluded that if all biologics were considered equally effective, then etanercept, adalimumab and golimumab had almost equal costs and equal QALYs, and all had an ICER of about £15 000 per QALY versus palliative care, whilst infliximab, with a higher acquisition cost, was dominated by the other biologics.

The Appraisal Committee altered its position between the Appraisal Consultation Document and the Final Appraisal Determination. It ultimately recommended that golimumab be provided as an option for the treatment of active and progressive PsA in adults only if (i) it is used as described for other tumour necrosis factor inhibitor treatments in ‘Etanercept, infliximab and adalimumab for the treatment of psoriatic arthritis’ (NICE clinical guideline 199); and (ii) the manufacturer provides the 100 mg dose of golimumab at the same cost as the 50 mg dose.