Liposomal Cytarabine (DepoCyte^™Injection) Is Cost-Effective Compared with Standard Cytarabine for the Intrathecal Treatment of Patients with Lymphomatous Meningitis.

Background and Objective : The clinical benefit of liposomal cytarabine (DepoCyte^TM injection) for the intrathecal treatment of lymphomatous meningitis has been demonstrated in a randomised controlled trial (Glantz M. et al. J Clin Oncol 1999;3110-3116 ). Liposomal cytarabine has recently become available in the UK at a cost considerably above that of standard cytarabine (1,250GBP per dose compared to 4GBP). A cost-utility analysis (CUA) comparing liposomal cytarabine versus standard cytarabine was conducted from the perspective of the UK National Health Service to determine whether or not liposomal cytarabine is a cost-effective treatment option for patients with lymphomatous meningitis.

Methods: Using data from the clinical trial, each patient’s survival time was partitioned according to the presence of progressive neurological disease. Utility estimates for two health states, progression and non-progression, were derived from clinical experts using a time-tradeoff exercise and assigned to each patient according to the period of time they remained in each health state. Observed response rates from the clinical trial were used to model expected quality adjusted life year (QALY) estimates for each treatment arm. Health care costs were estimated using resource data from the clinical trial and unit costs from the literature. Probabilistic analyses were used to estimate the expected cost per QALY gained with liposomal cytarabine, taking into account the uncertainty surrounding model input parameters.

Results: From a total of 33 randomised patients, response status was available for 29. 13 of 16 patients treated with liposomal cytarabine responded to treatment compared to 3 of 13 patients treated with standard cytarabine (81 vs. 23%; p=0.003). The mean total expected healthcare cost per patient was estimated to be 8,275GBP (+/−796) for patients treated with liposomal cytarabine and 3,238GBP (+/−494) for those treated with standard cytarabine. Patients treated with liposomal cytarabine accrued on average 0.27 (+/−0.027) QALYs compared to 0.15 (+/−0.025) QALYs in the standard cytarabine arm. The mean expected incremental cost per QALY gained with liposomal cytarabine was 47,764GBP (95%CI = 22,921–95,676). This estimate of cost-effectiveness was particularly sensitive to the health state utilities for progression and non-progression.

Conclusion : The results of this analysis suggest that liposomal cytarabine is a cost-effective treatment option for patients with lymphomatous meningitis. Although the incremental cost-effectiveness ratio (ICER) is close to the probable willingness-to-pay threshold, the results of this analysis should be evaluated in the context of a severe disease with few effective treatment options. Further research into patient preferences for the health states modelled here would be valuable given the sensitivity of QALY estimates to this variable.