OBJECTIVES: The UK National Institute for Health and Clinical Excellence (NICE) recommended gefitinib for use first line in locally advanced or metastatic, EGFR mutation positive, NSCLC when supplied via the SPA scheme. This was based on the mean duration of treatment of 8.8 months observed in the IPASS study. The single fixed payment under the scheme is triggered at the order of the third pack and covers a patient for their total supply of gefitinib treatment. The objective of this study is to evaluate the length of gefitinib therapy and confirm the value accepted by NICE. METHODS: The SPA administrative database started in September 2009 to collect information on packs (30 days therapy/pack) dispensed to patients. This retrospective study includes patients fulfilling NICE eligibility criteria and with at least 12 months potential follow-up and for whom the NHS was invoiced. Median time to treatment cessation was estimated from a Kaplan-Meier curve of packs supplied to patients and mean number of packs dispensed from a parametric failure time model. RESULTS: 265 patients met the study eligibility criteria. These patients, for whom the NHS was invoiced the single fixed payment, received a median of 12 packs 95%CI[10,13] with a mean of 16.2 95%CI[14.1,18.6] packs per patient. CONCLUSIONS: The results of this observational study indicate that the average length of gefitinib therapy in UK clinical practice is at least as long as assumed under SPA which confirms the value accepted by NICE.