A systematic review of economic evaluations in second and later lines of therapy for the treatment of non-small cell lung cancer.

INTRODUCTION: Non-small cell lung cancer (NSCLC) is associated with high morbidity and mortality. Surgery is generally accepted as the first-line treatment in patients with advanced/metastatic NSCLC, followed by radiotherapy and chemotherapy as second-line treatments. Docetaxel or erlotinib are generally recommended as the first-line chemotherapy option. The objective of this review was to identify previously published economic evaluations in NSCLC for second- and later-line treatments in order to (i) determine common modelling approaches and (ii) establish the relative cost effectiveness of these treatments. An overview of model critique was also produced to identify common criticisms from health technology assessment (HTA) bodies on the models submitted.

METHODS: MEDLINE, Embase, EconLit, MEDLINE in Process(®) and NHS Economic Evaluation Database (NHSEED) were searched (database start-October 2011), along with proceedings from eight major conferences (2007-2011). National Institute for Health and Clinical Excellence (NICE), Scottish Medicines Consortium (SMC), Pharmaceutical Benefits Advisory Committee (PBAC) and Canadian Agency for Drugs and Technologies in Health (CADTH) websites and the International Network of Agencies for Health Technology Assessment (INAHTA) database were also searched for appraisals in second- or later-line NSCLC. All published studies and HTA appraisals that reported economic evaluations of interventions used in current clinical practice as second- or later-line treatment in patients with advanced/metastatic NSCLC were included. Only studies in English were considered for inclusion. Studies which met the eligibility criteria after the screening of full-text articles were extracted by a reviewer and checked by a second party. Where multiple publications were identified describing a single study, the extracted data were compiled into one entry.

RESULTS: A total of 29 studies were included which clearly evaluated second-line or later-line regimens. Most studies were either cost-effectiveness or cost-utility evaluations. Three-state transition Markov models were frequently used in cost-effectiveness and cost-utility evaluations. The model inputs were well reported and commonly consisted of data from pivotal trials. Sensitivity analyses were conducted in the majority of studies and covered variables such as cost, effectiveness, hospitalization and treatment duration. Therapies (docetaxel, pemetrexed and erlotinib) are for the most part cost-effective/cost-saving second-line therapies compared with best supportive care (BSC). Six erlotinib HTAs, across NICE, SMC, and PBAC, and four pemetrexed HTAs, one by NICE and three by SMC, were identified. The CADTH website did not provide sufficient detail on the appraisals and was excluded. Certain aspects of the models and model assumptions, e.g. efficacy inputs, were criticized or determined unjustifiable by the NICE, SMC and PBAC appraisal committees. Erlotinib and pemetrexed were considered to be cost effective versus docetaxel by NICE and SMC in the final submissions. PBAC considered erlotinib to be cost effective versus BSC following a price reduction in 2008.

CONCLUSION: Three-state Markov models are often used to conduct economic analysis in NSCLC and are regarded as appropriate to HTA agencies. Docetaxel, erlotinib and BSC are suitable comparators that should be considered for use in the model in the UK and Australia. Further, manufacturers should carefully select underlying assumptions used in the model, for both costs and clinical inputs, where the latter is derived from direct head-to-head trial data.