Alteplase for the treatment of acute ischaemic stroke: a single technology appraisal

Abstract

This paper presents a summary of the evidence review group report into the clinical effectiveness and cost-effectiveness of alteplase for the treatment of acute ischaemic stroke, in accordance with the licensed indication, based upon the evidence submission from the manufacturer to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The submitted clinical evidence included several randomised controlled trials indicating that, in highly selected patients, alteplase administered at a licensed dose within 3 hours of the onset of acute ischaemic stroke is associated with a statistically significant reduction in the risk of death or dependency at 3 months compared with placebo, despite a significantly increased risk of symptomatic intracranial haemorrhage within the first 7–10 days. Data from the National Institute of Neurological Disorders and Stroke (NINDS) trial suggest that the benefit of treatment is sustained at 6 and 12 months. However, data from observational studies suggest that few patients with acute ischaemic stroke will be eligible for alteplase therapy under the terms of the current licensing agreement. In particular, many patients will be excluded by virtue of their age, and many more by the restriction of therapy to patients in whom treatment can be initiated within 3 hours of symptom onset. The manufacturer’s submission included a state transition model evaluating the impact of treatment with alteplase within 3 hours of onset of stroke symptoms compared to standard treatment reporting that, in the base-case analysis, alteplase was both less costly and more effective than standard treatment. This increased to a maximum of approximately £4000 upon one-way sensitivity analysis of the parameters. The probabilistic sensitivity analysis presented within the submission suggests that the probability that alteplase has a cost-effectiveness ratio greater than £20,000 per quality-adjusted life-year (QALY) gained is close to 1 (0.99). The results of the short-term model demonstrate that alteplase is cost-effective over a 12-month period, with an incremental cost-effectiveness ratio of £14,026 per QALY gained. This increased to a maximum of £50,000 upon one-way sensitivity analysis of the parameters. At 12 months, the probabilistic sensitivity analysis presented within the submission suggests that the probability that alteplase has a cost-effectiveness ratio greater than £20,000 per QALY gained is approximately 0.7. The guidance issued by NICE in April 2007 as a result of the STA states that alteplase is recommended for the treatment of acute ischaemic stroke only when used by physicians trained and experienced in the management of acute stroke and in centres with the required facilities.