Millham, L et al. Clinical and Economic Impact of Ibalizumab for People with Multidrug-Resistant HIV in the United States. Journal of Acquired Immune Deficiency Syndromes: February 1, 2020 – Volume 83 – Issue 2 – p 148–156. doi: 10.1097/QAI.0000000000002241

Ibalizumab (Trogarzo®) is a monoclonal antibody that prevents HIV cell entry by binding to a specific region of the host CD4 cell receptor. This agent was approved by the FDA in March 2018 for use in combination with other antiretrovirals in adults with multidrug resistant (MDR) HIV-1 infection failing their current ART regimen. Ibalizumab is given intravenously over 15 to 30 minutes every 2 weeks. This study projected the clinical outcomes, cost-effectiveness, and budget impact of ibalizumab plus an optimized background regimen (OBR) for people with MDR HIV in the United States. The authors used what is called the “Cost-Effectiveness of Preventing AIDS Complications microsimulation model.” They compared two treatment strategies for MDR HIV: (1) OBR + ibalizumab and (2) OBR alone. The efficacy of Ibalizumab was from clinical trial data which included 85% male patients with a mean age 49 years. Six-month viral suppression was 50% with IBA + OBR and 0% with OBR. The initial ibalizumab loading dose cost $10,500 and subsequent ibalizumab injections cost $8400/month. The estimated cost of the OBR was $4500/month. Incremental cost-effectiveness ratios (ICERs) were calculated using discounted quality-adjusted life years (QALYs). For this study, cost-effectiveness ratios of less than $100,000/QALY were considered cost-effective. In the base case, 5-year survival increased from 38% with OBR to 47% with IBA + OBR. The calculated lifetime costs were $661,800/person with IBA + OBR and 301,700/person with OBR alone. The ICER for IBA + OBR compared with OBR was $260,900/QALY. Ibalizumab + OBR was not cost-effective even with 100% efficacy and only became cost-effective if ibalizumab cost was reduced by ≥ 88%. For the estimated 12,000 people with MDR HIV in the U.S., IBA + OBR would increase medical costs by $1.8 billion over 5 years. The study concludes that for persons with MDR HIV who lack other treatment options, ibalizumab will substantially increase survival when effective, but adding this drug to an OBR is not cost-effective. However, the small number of eligible patients in the United States would make the overall budget impact fairly small.

Author’s Commentary:

Ibalizumab is highly effective but an expensive agent for treating MDR HIV. The annual wholesale acquisition cost of IBA is about $118,000. In recent years there has been a decline in the number of patients with MDR and with good adherence to Integrase-inhibitor based-regimens the majority of patients should attain and maintain an undetectable viral load. A small number of patients should need IBA although it is useful to have as an option. Other agents including CD4 attachment inhibitors (UB-421), capsid inhibitors (GS-6207) and maturation inhibitors (GSK2838232) remain in the pipeline and may eventually have a role for naïve, treatment experienced, and patients with MDR.