This paper presents a summary of the evidence review group (ERG) report into the clinical effectiveness and cost-effectiveness of pemetrexed for the maintenance treatment of locally advanced or metastatic non-small cell lung cancer (NSCLC), in accordance with the licensed indication, based upon the evidence submission from the manufacturer (Eli Lilly) to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The primary clinical outcome measure was progression free survival (PFS). Secondary outcomes included overall survival (OS), time to worsening of symptoms, objective tumour response rate, adverse events and changes in lung cancer symptom scale. Data for two populations were presented: patients with non-squamous NSCLC histology and patients with adenocarcinoma histology. The clinical evidence was derived from a double-blind, placebo-controlled randomised controlled trial (RCT), the JMEN trial. The trial compared the use of pemetrexed + best supportive care (BSC ) as maintenance therapy, with placebo + BSC in patients with NSCLC (n = 663) who had received four cycles of platinum-based chemotherapy (CTX) and whose disease had not progressed. In the licensed population (patients with non-squamous histology), the trial demonstrated greater median PFS for patients treated with pemetrexed than for patients in the placebo arm [4.5 vs 2.6 months; hazard ratio (HR) 0.44; 95% confidence interval (CI) 0.36 to 0.55, p < 0.00001]. Median OS was also greater for the pemetrexed- treated patients (15.5 vs 10.3 months; HR 0.70; 95% CI 0.56 to 0.88, p = 0.002). In addition, tumour response and disease control rates were statistically significantly greater for patients who received pemetrexed. Patient survival rates at 1 year and 2 years were higher in the pemetrexed arm. The incremental cost-effectiveness ratios (ICERs) estimated by the manufacturer's model were 33,732 pounds per quality adjusted life-year (QALY) for the licensed nonsquamous population, and 39,364 pounds per QALY for the adenocarcinoma subgroup. Both of these ICERs were above the standard NICE willingness-to-pay range (20,000 pounds-30,000 pounds per QALY). The manufacturer also presented a case for pemetrexed to be considered as an end of life treatment. The ERG identified a number of problems in the economic model presented by the manufacturer; after correction, the base case ICER was re-estimated as 51,192 pounds per QALY gained and likely to exceed NICE's willingness-to-pay thresholds. Following a revised economic analysis submitted by the manufacturer, the AC accepted that an ICER of 47,000 pounds per QALY gained was most plausible. The AC also considered that maintenance treatment with pemetrexed fulfilled the end of life criteria.The guidance issued by NICE, on 20 June 20 2010, in TA190 as a result of the STA states that: People who have received pemetrexed in combination with cisplatin as first-line chemotherapy cannot receive pemetrexed maintenance treatment. 1.1 Pemetrexed is recommended as an option for the maintenance treatment of people with locally advanced or metastatic non-small-cell lung cancer other than predominantly squamous cell histology if disease has not progressed immediately following platinum-based chemotherapy in combination with gemcitabine, paclitaxel or docetaxel.