Abstract and Introduction
Background: We projected the clinical outcomes, cost-effectiveness, and budget impact of ibalizumab plus an optimized background regimen (OBR) for people with multidrug-resistant (MDR) HIV in the United States.
Methods: Using the Cost-Effectiveness of Preventing AIDS Complications microsimulation model and a health care sector perspective, we compared 2 treatment strategies for MDR HIV: (1) IBA + OBR—ibalizumab plus OBR and (2) OBR—OBR alone. Ibalizumab efficacy and cohort characteristics were from trial data: mean age 49 years, 85% male, and mean CD4 150/μL. Six-month viral suppression was 50% with IBA + OBR and 0% with OBR. The ibalizumab loading dose cost $10,500, and subsequent ibalizumab injections cost $8400/month; OBR cost $4500/month. Incremental cost-effectiveness ratios (ICERs) were calculated using discounted (3%/year) quality-adjusted life years (QALYs) and costs. ICERs ≤$100,000/QALY were considered cost-effective. We performed sensitivity analysis on key parameters and examined budget impact.
Results: In the base case, 5-year survival increased from 38% with OBR to 47% with IBA + OBR. Lifetime costs were $301,700/person with OBR and $661,800/person with IBA + OBR; the ICER for IBA + OBR compared with OBR was $260,900/QALY. IBA + OBR was not cost-effective even with 100% efficacy. IBA + OBR became cost-effective at base case efficacy if ibalizumab cost was reduced by ≥88%. For an estimated 12,000 people with MDR HIV in the United States, IBA + OBR increased care costs by $1.8 billion (1.5% of total treatment budget) over 5 years.
Conclusions: For people with MDR HIV lacking other treatment options, ibalizumab will substantially increase survival when effective. Although adding ibalizumab to OBR is not cost-effective, the low number of eligible patients in the United States makes the budget impact relatively small.
Most people with HIV can achieve virologic suppression with currently available antiretroviral therapy (ART). A small subset of patients (estimated at 12,000 in the United States), however, have multidrug-resistant (MDR) HIV infection for which standard antiretroviral treatments are ineffective.[1–5] Until recently, the only therapeutic option for individuals who had MDR HIV and multiple failed regimens was treatment with a best-possible or "optimized" regimen consisting of a combination of the most potent antiretroviral drugs specific to their resistance profiles. With severe MDR HIV, this strategy does not lead to virologic suppression but can slow CD4 count decline[6–8] due to the impaired viral fitness of some resistant strains.
Approved by the U.S. Food and Drug Administration (FDA) under the Orphan Drug Act in March 2018, ibalizumab is the first monoclonal antibody licensed to treat MDR HIV.[9,10] This drug, when combined with an optimized background regimen (OBR), showed promise in its first phase 3 trial, TMB-301, with 50% of patients achieving virologic suppression at 6 months. All patients suppressed at 6 months who completed the 12 month trial (TMB-311) showed sustained suppression at 12 months. These results suggest that ibalizumab combined with OBR is an effective treatment and may improve outcomes for people with MDR HIV.
Biologics, including monoclonal antibodies (mAbs), are among the most expensive drugs available in the United States.[13,14] Pharmaceutical companies attribute the high cost of mAbs to dose requirements and manufacturing complexity. Ibalizumab is no exception—with treatment administered intravenously every 2 weeks at an infusion center or at home with homecare service assistance, ibalizumab treatment alone costs ~$111,000/year in 2018 US dollars.[15–17] Salvage regimens typically cost ~$54,000/year; thus, total treatment costs for someone on ibalizumab and a salvage OBR are ~$164,000/year, 3 times as high as treatment with a salvage regimen alone. Our objective was to project the clinical impact, cost, and cost-effectiveness of ibalizumab over the short and long term for people with MDR HIV in the United States.
J Acquir Immune Defic Syndr. 2020;83(2):148-156. © 2020 Lippincott Williams & Wilkins