Cost-Utility Analysis of Esketamine for Patients with Treatment-Resistant Depression in Italy.

Aim: Major depressive disorder is considered one of the most frequent diseases in the general population, and treatment-resistant depression (TRD) represents the subset with more significant clinical and social impact. Large, robust phase III studies have shown safety and efficacy of esketamine nasal spray plus SSRI/SNRI antidepressants (ADs) compared with SSRI/SNRI plus placebo nasal spray in patients with TRD. The main aim of this study was to perform a cost-utility analysis comparing esketamine plus ADs with ADs alone in TRD patients, from the societal perspective in Italy. A secondary analysis focused on the National Healthcare Service (NHS) perspective.

Methods: A Markov multistate model has been developed to estimate quality-adjusted life years and economic outcomes of both treatment strategies over 5 years considering the initiation of esketamine in the different treatment lines, from 3 to 5 (3L-5L). The model has been populated with data from literature and real-world evidence. The analysis from the societal perspective considered direct healthcare costs and patients' productivity losses. In addition to the incremental cost-utility ratio (ICUR), the incremental net monetary benefit (INMB) has been calculated as (incremental benefit × WTP) - incremental cost and by applying a willingness-to-pay (WTP) of 50,000€/QALY. Deterministic and probabilistic sensitivity analyses have been performed to assess the robustness of the model results.

Results: From the societal perspective, the ICUR ranged between 16,314€ and 22,133€ per QALY according to the different treatment lines, while it was over the threshold of 100,000€/QALY for the NHS perspective. The INMB was positive and ranged from 2259€ to 2744€ across treatment lines in the societal perspective; the INMB begins to occur earlier when moving towards subsequent lines of treatment (3.9 years for 3L, 3.6 years for 4L and 3.5 years for 5L). The analyses showed also that the advantage in terms of INMB is maintained for a wide range of societal preferences expressed by WTP thresholds, and in particular for values above 22,200€, 16,400€ and 17,100€ for 3L, 4L and 5L, respectively.

Conclusion: The study showed that esketamine may be a cost-effective opportunity from the societal perspective for the management of patients with treatment-resistant depression. In the future, data collected from observational studies or registries, which can include the collection of productivity losses and also costs sustained by the patients, will be able to provide further evidence in order to improve the reliability of the model results.