Long-Acting Antiretroviral Therapy for Breastfeeding Women With HIV Experiencing Barriers to Adherence in Zimbabwe: Modeling Clinical Impact and Cost-effectiveness

Abstract

Background: Long-acting antiretroviral therapy (LA-ART) may reduce adherence barriers for postpartum women with HIV (PPWH), reducing vertical transmission (VT) and improving pediatric life expectancy (pLE), but efficacy and drug costs are uncertain.

Methods: Using a microsimulation model, we simulated mother-infant dyads for two cohorts of PPWH engaged in care, receiving oral tenofovir/lamivudine/dolutegravir (TLD) in pregnancy, and facing adherence challenges in Zimbabwe: mothers without (NVS) and with (VS) viral suppression at delivery. We modeled two post-delivery strategies: standard of care (SOC: TLD continuation) or LA-ART (switching to LA-cabotegravir/rilpivirine [CAB/RPV]). Key inputs included: 6-month-postpartum viral suppression (LA-ART: NVS = 85%/VS = 90%; SOC: NVS = 63%/VS = 78%), ART costs/year (CAB/RPV=$144/TLD=$43.20), and VT risk (0.06%-0.89%/month, range by maternal RNA). Outcomes include VT, pLE, costs (maternal ART in breastfeeding plus pediatric HIV-related lifetime care), and incremental cost-effectiveness ratios (ICERs, $/year-of-life-saved [YLS]; cost-effective: ICER≤$800/YLS [0.5× Zimbabwe GDP].

Results: LA-ART would reduce VT compared with SOC (NVS: from 7.49% to 6.58%/VS: from 4.17% to 3.80%), averting ∼160 infections/year in Zimbabwe. For NVS, LA-ART would improve pLE (SOC = 66.08y, LA-ART = 66.40y) at nearly equal cost (SOC = $764/child, LA-ART = $763/child); LA-ART would not be cost-effective if CAB/RPV cost >$228/year or 6-month suppression were <74%. For VS, LA-ART would lead to higher pLE and costs (67.52y, $555/child) than SOC (67.40y, $445/child), with ICER=$2449/YLS; LA-ART would become cost-effective if CAB/RPV cost ≤$84/year.

Conclusions: LA-ART for breastfeeding women experiencing adherence challenges could reduce infant infections. If efficacies and costs are confirmed, LA-ART for NVS women would improve outcomes and be minimally cost-saving; for VS women, LA-ART would be cost-effective in Zimbabwe at costs ≤$84/year.

Keywords: HIV; breastfeeding; long-acting antiretroviral therapy; simulation modeling; vertical transmission.