Axicabtagene ciloleucel and tisagenlecleucel may be cost effective at their list prices of $373,000 for adults with diffuse large B-cell lymphoma (DLBCL), under the condition that they deliver long-term durable responses among a high proportion of patients, a cost-effectiveness analysis found. The analysis was recently published in the Journal of Clinical Oncology and also reported at the 2019 American Society of Clinical Oncology Annual Meeting.
“This is a high-quality and transparent cost-effectiveness analysis that is a useful addition to the peer-reviewed literature on the value of CAR T-cell therapy,” said Joshua Roth, PhD, MHA, assistant member of the Hutchinson Institute for Cancer Outcomes Research at Fred Hutchinson Cancer Research Center in Seattle, during an interview with Cancer Network.
Two cost-effectiveness analyses have already been published for the two anti-CD19 chimeric antigen receptor (CAR) T-cell therapies approved by the US Food and Drug Administration for adults with DLBCL, the first of which was authored by Roth and colleagues in late 2018. The second was published in JAMA Network Open earlier this year in February. “While the cost per quality-adjusted life year gained slightly differs across studies, they all generally support the acceptable value of these treatments assuming that large proportions of patients continue to experience durable responses after the trial periods,” Roth said. “This is an important assumption for the value of these therapies.”
In the current cost-effectiveness analysis, the study authors modeled long-term outcomes data to create possible scenarios for each CAR T-cell therapy. In an optimistic scenario, with a 40% 5-year progression-free survival (PFS), axicabtagene ciloleucel increased life expectancy by 8.2 years at $129,000/quality-adjusted life year (QALY) gained. At a 30% 5-year PFS rate, improvements in life expectancy were more modest, at 6.4 years. For tisagenlecleucel, assuming a 35% 5-year PFS rate, this treatment increased life expectancy by 4.6 years at $168,000/QALY gained. At a 25% 5-year PFS rate, improvements in life expectancy were smaller at 3.4 years and more expensive ($223,000/QALY gained).
Assuming a willingness to pay a threshold of $150,000 per QALY, which is the generally accepted threshold in such analyses, axicabtagene ciloleucel was cost-effective for 73% of simulations if the 5-year PFS rate was 40% and tisagenlecleucel was cost-effective for 33% of simulated patients if the 5-year PFS rate was 35%. However, neither CAR T-cell therapy was deemed cost-effective if the willingness-to-pay threshold was lowered to $100,000 per QALY because both therapies were cost-effective in less than 15% of simulations.
In a budget impact analysis, the current cost of both CAR T-cell therapies was estimated to drive up healthcare spending in the United States during the first 5 years by $12 billion for axicabtagene ciloleucel and $9 billion for tisagenlecleucel. Roth noted that the budget impact analysis is an aspect that has not been previously reported in the peer-reviewed literature. “These estimates of increases in US healthcare expenditures of $12 billion and $9 billion for axicabtagene ciloleucel and tisagenlecleucel are substantial amounts that warrant attention from public and private healthcare payers,” he said.
Roth cautioned that it’s unclear whether the budget impact in the real-world setting would be that large because the analysis assumes that all CAR T-cell–eligible patients would switch to CAR T-cell therapy from salvage chemoimmunotherapy on day 1 of the timeline for the analysis. “In reality, I would expect a gradual shift toward increased use of CAR T-cell therapy over a 5-year period, and this would result in somewhat smaller, but still potentially substantial, budget impact.”
When asked for ways to make the therapies more cost-effective, Roth said, “I don’t expect the CAR T-cell therapy manufacturers to decrease list prices in the US, so I agree with [the study authors] that the most likely pathway to improved value is outcomes-based contracting that ties reimbursement to clinical outcomes.”