Importance: A phase 2 trial comparing talimogene laherparepvec plus ipilimumab vs ipilimumab monotherapy in patients with advanced unresectable melanoma found no differential benefit in progression-free survival (PFS) but noted objective response rates (ORRs) of 38.8% (38 of 98 patients) vs 18.0% (18 of 100 patients), respectively.
Objective: To perform an economic evaluation of talimogene laherparepvec plus ipilimumab combination therapy vs ipilimumab monotherapy.
Design, Setting, and Participants: For PFS, cost-effectiveness and cost-utility analyses using a 2-state Markov model (PFS vs progression or death) was performed. For ORRs, cost-effectiveness analysis of the incremental cost of 1 additional patient achieving objective response was performed. In this setting based on a US payer perspective (2017 US dollars), participants were patients with advanced unresectable melanoma.
Main Outcomes and Measures: The PFS life-years and PFS quality-adjusted life-years were determined, and the associated incremental cost-effectiveness ratios (ICERs) and incremental cost-utility ratios (ICURs) were estimated. Also estimated was the ICER per 1 additional patient (out of 100 treated patients) achieving objective response. Base-case analyses were validated by sensitivity analyses.
Results: In PFS analyses, the cost of talimogene laherparepvec plus ipilimumab ($494 983) exceeded the cost of ipilimumab monotherapy ($132 950) by $362 033. The ICER was $2 129 606 per PFS life-years, and the ICUR was $2 262 706 per PFS quality-adjusted life-year gained. Probabilistic sensitivity analyses yielded an ICER of $1 481 208 per PFS life-year gained and an ICUR of $1 683 191 per PFS quality-adjusted life-year gained. In 1-way sensitivity analyses, the PFS hazard ratio and the utility of response were the most influential parameters. Talimogene laherparepvec plus ipilimumab has a 50% likelihood of being cost-effective at a willingness-to-pay threshold of $1 683 191 per PFS quality-adjusted life-year gained. In ORR analyses, talimogene laherparepvec plus ipilimumab ($474 904) vs ipilimumab alone ($132 810), a $342 094 difference, yielded an ICER of $1 629 019 per additional patient achieving objective response. In subgroup analyses by disease stage and BRAFV600E mutation status, ICERs ranged from $1 069 044 to $17 104 700 per 1 additional patient achieving objective response.
Conclusions and Relevance: The cost to gain 1 additional progression-free quality-adjusted life-year, 1 additional progression-free life-year, or to have 1 additional patient attain objective response is about $1.6 million. This amount may be beyond what payers typically are willing to pay. Combination therapy of talimogene laherparepvec plus ipilimumab does not offer an economically beneficial treatment option relative to ipilimumab monotherapy at the population level. This should not preclude treatment for individual patients for whom this regimen may be indicated.