Although adding ibalizumab to an optimized background regimen of antiretroviral therapy (ART) is not cost-effective, ibalizumab substantially increased survival for individuals with multidrug-resistant HIV, a group lacking other treatment options, and the small size of this population in the United States makes the effects on budget relatively minor, according to research presented at the 10th IAS Conference on HIV Science, held July 21 to 24, in Mexico City, Mexico.
Ibalizumab is the first FDA-approved monoclonal antibody for the treatment of multidrug-resistant HIV. The current study projected cost effectiveness and budget effects of ibalizumab and background ART for participants with multidrug-resistant HIV compared with background ART alone, using the Cost-Effectiveness of Preventing AIDS Complications model. Long-term clinical outcomes were determined using ibalizumab efficacy and patient characteristic data from the phase 3 trial. Endpoints included life expectancy in quality-adjusted life years, 5-year survival, lifetime care costs, and transmissions/100 person-years. Quality-adjusted life years and costs and discounted 3% per year were used to calculate the incremental cost-effectiveness ratio, with a value < $100,000/quality-adjusted life years considered to be cost-effective. Sensitivity analyses were performed on key parameters, and the US health sector budget impact for an estimated 5,000 individuals with multidrug-resistant HIV were also examined.
Mean initial CD4 count for participants was 150/µl. At 24 weeks, viral suppression for ibalizumab and background ART was 50%, and participants incurred a one-time cost of $10,500 for the ibalizumab loading dose and a monthly cost of $13,700 for background ART and subsequent ibalizumab injections. Participants in background ART only group did not achieve viral suppression but incurred a medication cost of $4,500 a month.
The 5-year survival with background ART only increased from 38% to 47% with the addition of ibalizumab, and quality-adjusted life years also increased from 3.74 to 5.12, respectively. Lifetime costs with background ART only were $299,600 per person compared with $660,700 per person with the addition of ibalizumab.
Researchers noted that ibalizumab and background ART only became cost-effective if the cost of IBA was reduced by over 88%, and there was no threshold of efficacy at which this combination treatment became cost-effective.
Rates of 5-year transmission decreased from 4.81/100 person-years with background ART only to 3.51/100 person-years with the addition of ibalizumab. The addition of ibalizumab also increased costs by $708 million over 5 years for the estimated 5,000 people with multidrug-resistant HIV in the United States, which is approximately 0.6% of HIV treatment costs over that time.
Study investigators concluded, “Ibalizumab will substantially increase survival for patients with multidrug-resistant HIV, a group currently lacking other treatment options. While [adding ibalizumab to optimized background ART] is not cost-effective, the small number of eligible patients makes the budget impact of adding ibalizumab to OBR relatively small in the US.”
Millham L, Scott J, Sax P, et al. Clinical and economic impact of ibalizumab for patients with multidrug-resistant HIV in the United States. Presented at: The 10th IAS Conference on HIV Science; July-21-24, 2019; Mexico City, MX. Abstract 1214.