Model suggests lower prices could improve esketamine’s value in Hong Kong

The study examined whether esketamine nasal spray represents good value for Hong Kong’s health system when used for adults with treatment-resistant depression. The researchers defined treatment-resistant depression as depression that has not responded to at least two adequately given antidepressant regimens.

Esketamine was studied alongside an oral antidepressant. It is given under healthcare supervision, which adds service costs as well as medication costs. The researchers did not enroll and follow a group of patients. Instead, they used a Markov cohort model, a computer-based method that estimates how a group may move between health states over time using available evidence and assumptions.

The model ran for five years in four-week cycles and took the perspective of the Hong Kong healthcare payer. It compared esketamine plus an antidepressant with six third-line approaches: two antidepressants used together; an antidepressant with an antipsychotic medicine or lithium, called augmentation; psychotherapy alone; psychotherapy with an antidepressant; repetitive transcranial magnetic stimulation, or rTMS, with an antidepressant; and electroconvulsive therapy, or ECT, with an antidepressant.

The main measures were quality-adjusted life-years, known as QALYs, and incremental cost-effectiveness ratios. A QALY combines length of life with health-related quality of life. An incremental cost-effectiveness ratio estimates the extra cost associated with an additional QALY compared with another option.

The researchers used a willingness-to-pay threshold of US$50,000 per QALY. In the main analysis, esketamine was not cost-effective compared with augmentation therapy, combination antidepressant therapy, psychotherapy, or psychotherapy plus an antidepressant. Its estimated cost per additional QALY in these comparisons ranged from US$134,127 to US$312,750.

Combination antidepressant therapy was the most cost-effective of all the strategies assessed. The model found esketamine was more cost-effective than rTMS, which was described as dominated. In economic evaluations, “dominated” means an option is estimated to cost more while providing fewer health gains than the alternative. Compared with ECT, the estimated ratio for esketamine was US$322,407 per QALY, well above the study’s US$50,000 threshold.

The researchers also tested how results changed under different assumptions. These analyses included alternative esketamine doses, ways of delivering the treatment, and comparisons with other treatment options. The abstract does not provide the detailed results of those analyses, but the authors concluded that price negotiation, more efficient service delivery, and alternative dosing strategies could potentially improve esketamine’s value.

This research does not show that one treatment will work better for every person with treatment-resistant depression. Cost-effectiveness is not the same as clinical effectiveness, and the study was designed to inform healthcare funding and treatment-planning decisions in Hong Kong rather than to give personal treatment advice.

The authors also noted an important limitation: the model relied on indirect comparisons and assumptions drawn from clinical trials with different patient groups. Those data may not fully match people’s real-world characteristics or the treatment paths they follow in Hong Kong. Further evidence using comparable patient populations and real-world treatment data could help refine these estimates.