Optimal Control of Hepatitis C Antiviral Treatment Programme Delivery for Prevention amongst a Population of Injecting Drug Users

Abstract

In most developed countries, HCV is primarily transmitted by injecting drug users (IDUs). HCV antiviral treatment is effective, and deemed cost-effective for those with no re-infection risk. However, few active IDUs are currently treated. Previous modelling studies have shown antiviral treatment for active IDUs could reduce HCV prevalence, and there is emerging interest in developing targeted IDU treatment programmes. However, the optimal timing and scale-up of treatment is unknown, given the real-world constraints commonly existing for health programmes. We explore how the optimal programme is affected by a variety of policy objectives, budget constraints, and prevalence settings. We develop a model of HCV transmission and treatment amongst active IDUs, determine the optimal treatment programme strategy over 10 years for two baseline chronic HCV prevalence scenarios (30% and 45%), a range of maximum annual budgets (50,000–300,000 per 1,000 IDUs), and a variety of objectives: minimising health service costs and health utility losses; minimising prevalence at 10 years; minimising health service costs and health utility losses with a final time prevalence target; minimising health service costs with a final time prevalence target but neglecting health utility losses. The largest programme allowed for a given budget is the programme which minimises both prevalence at 10 years, and HCV health utility loss and heath service costs, with higher budgets resulting in greater cost-effectiveness (measured by cost per QALY gained compared to no treatment). However, if the objective is to achieve a 20% relative prevalence reduction at 10 years, while minimising both health service costs and losses in health utility, the optimal treatment strategy is an immediate expansion of coverage over 5–8 years, and is less cost-effective. By contrast, if the objective is only to minimise costs to the health service while attaining the 20% prevalence reduction, the programme is deferred until the final years of the decade, and is the least cost-effective of the scenarios.

Treatment of Hepatitis C as Prevention: A Modeling Case Study in Vietnam

“…They projected that an immediate programme of maximum intensity designed to minimize prevalence, HCV health utility loss and health services costs (which we extrapolate most closely matches our approach) would achieve greater cost-effectiveness, as opposed to programmes with notably delayed implementation addressing more restricted policy objectives or finite prevalence reduction targets [32]. In their study of optimal treatment allocation, Zeiler et al determined that, as far as maximizing prevention benefits is concerned, HCV treatment should predominantly be allocated to IDUs not enrolled in MMT, as opposed to IDUs in MMT [7].…”

Global policy and access to new hepatitis C therapies for people who inject drugs

“…Expanded treatment access, in addition to widely-implemented harm reduction strategies, could greatly reduce or eliminate ongoing HCV transmission. Mathematical modelling using Australian, British and Canadian data suggest that treating a relatively small proportion of PWID with chronic HCV infection could significantly reduce HCV prevalence over 15 years [25][26][27][28][29]. These models demonstrate that the impact on prevalence varies on the number of individuals treated, the background prevalence of HCV, treatment effectiveness, M a n u s c r i p t [30].…”

Hepatitis C: Understanding factors that influence the physicians' treatment decisions

“…They discussed the importance of tailoring treatment efficiently to genotype, bodyweight and early viral response profiles of patients, and the challenges of trying to generalise cost-effectiveness results across geographical contexts, given differences in socio-demographic profiles, distribution of patients' clinical characteristics, utility profiles, resource use and pricing. Martin et al (2011) modelled cost-effectiveness of different HCV treatment strategies for injecting drug users and concluded that the optimal strategy depends on the priority goals (e.g. relative weight of cost-effectiveness, prevalence reduction, health utility and coverage).…”