Omalizumab for the treatment of severe persistent allergic asthma

Abstract

This paper presents a summary of the evidence review group (ERG) report into the clinical effectiveness and cost-effectiveness of omalizumab for the treatment of chronic severe persistent allergic asthma, in accordance with the licensed indication, based upon the evidence submission from Novartis to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The clinical evidence comes from a randomised controlled trial comparing omalizumab as an add-on to standard therapy with placebo and standard therapy over a 28-week treatment period. For the primary outcome of the rate of clinically significant asthma exacerbations, there was no statistically significant difference between treatment groups. However, after making a post hoc adjustment for a suggested ‘clinically relevant’ imbalance between trial arms in baseline exacerbation rate, the difference became marginally statistically significant. In terms of secondary outcomes, there were statistically significant differences favouring omalizumab over placebo in total emergency visits, Asthma Quality of Life Questionnaire scores, total symptom scores and lung function. Adverse events appeared to be similar between the trial arms. Results from three other publications are included in the manufacturer’s submission as supporting evidence for the effectiveness of omalizumab, despite not meeting the inclusion criteria which adhere strictly to the licensed indication. The ERG checked and provided commentary on the manufacturer’s model using standard checklists as well as undertook one-way sensitivity analysis, scenario analysis and a probabilistic sensitivity analysis. The cost-effectiveness analysis estimates the incremental costs and consequences of omalizumab as an add-on to standard therapy. The base-case analysis of the trial’s primary intention-to-treat population estimates a cost per quality-adjusted life-year of £30,647. The ERG conducted one-way sensitivity analyses for parameters omitted from the manufacturer’s submission sensitivity analysis. The results were most sensitive to variation in the utility values for omalizumab responders, and the unit cost of omalizumab. The guidance issued by NICE in November 2007 as a result of the STA states that omalizumab is recommended as a possible treatment for adults and young people over 12 years with severe persistent allergic asthma when their asthma meets certain conditions. Omalizumab treatment should be given along with the person’s current asthma medicines. It should be prescribed by a doctor who is experienced in asthma and allergy medicine at a specialist centre. If omalizumab does not control the asthma after 16 weeks, treatment should be stopped.