Analytical approach:
The analysis used an area under the curve partitioned survival Markov-type model to investigate disease progression in chronic myeloid leukaemia and the cost-effectiveness of the alternative strategies. The time horizon was 44 years (lifetime).
The authors stated that the analysis was carried out from the perspective of the UK National Health Service (NHS).
Effectiveness data:
Clinical data were derived from a systematic review of the published literature. Some data on disease progression and treatment duration were obtained from drug company submissions to NICE (National Institute for Clinical Excellence). The proportion of patients who achieved a major cytogenetic response was a key input and was used to estimate overall survival. Survival curves were used to extrapolate short-term data on progression-free survival over the model time horizon. Some assumptions were made, often based on experts’ opinions.
Monetary benefit and utility valuations:
Utility estimates were from six published studies that used the EQ5D (EuroQol) questionnaire.
Measure of benefit:
Life-years and quality-adjusted life-years (QALYs) were used as the summary benefit measures. An annual discount rate of 3.5% was applied to QALYs.
Cost data:
Costs included were drug acquisition, drug administration for interferon-alpha (district nurse visits), consultant visits, bone marrow tests, X-rays, computed tomography (CT) scans, blood transfusions, third-line treatment and in-patient terminal care. Costs of drugs were from the British National Formulary. Other costs were based on NHS reference costs and national tariffs. Patterns of resource consumption were based on the opinions of a sample of UK clinicians and dosages reported in the clinical trials. Costs were in UK pounds (£) and were discounted at an annual rate of 3.5%. The price year was 2010.
Analysis of uncertainty:
One-way sensitivity analyses were carried out for all model inputs. Ranges of values were obtained from published studies. A probabilistic sensitivity analysis was performed for all inputs. The sensitivity analysis focused in particular on progression-free survival and overall survival.