NEW YORK – The US Congressional Budget Office in a report detailed plans to estimate the financial impact of policies that could increase adoption of pricey gene therapies for sickle cell disease (SCD).
In the report released Tuesday, the CBO said it opted to focus on SCD since the US Food and Drug Administration approved two gene therapies for the disease in late 2023, and the first few patients received the treatments outside of clinical trials throughout 2024. However, the agency noted that drugmakers are developing gene therapies for numerous diseases.
The net budgetary effect of medical interventions typically depends on the "total federal share of costs for that intervention, any savings for patients who are treated successfully, and any changes in revenues or spending stemming from people living longer," the CBO said in the report.
"The lack of empirical evidence is likely to be a major challenge for any assessment of policies involving gene therapy because those therapies are relatively new and evidence of their use, costs, side effects, and effectiveness is limited," it added. "Substantial uncertainty also surrounds the costs of gene therapy and the capacity to deliver that therapy in the future; potential innovations could affect the evolution of those treatments."
As a first step, the CBO said it would estimate the population of SCD patients who would be eligible to receive a gene therapy based on the two products' labels and indications and how many of those patients would likely use gene therapy after factoring in insurance coverage, provider access, and acceptance of the treatments' risk-benefit profile.
In addition, the CBO would assess available evidence on the current use of similar medical services, such as the uptake of other cell or gene therapies, to inform its estimates. "Those examples may not translate well to the context of SCD gene therapy, however, given differences in the eligible populations, treatment costs, and other factors, such as the riskiness of the procedure and evidence on the duration of effects," the CBO acknowledged.
From there, the CBO would estimate how the number of people receiving treatment would affect federal expenditures and revenues across a standard 10-year projection period, and potentially longer.
The CBO would project treatment costs based on current law and compare those to a landscape in which the federal government institutes new policies to increase adoption of such treatments. For example, the US could establish a higher federal matching rate for gene therapy, in which it pays a larger share of treatment cost for enrollees in Medicaid, which provides coverage for a large proportion of SCD patients. That approach would have a different per unit treatment cost than a potential policy that would establish a value-based payment approach for gene therapies tied to outcomes.
The CBO added that insurance premiums could change if policies to increase adoption of gene therapy affect spending among patients enrolled in employer-based health insurance. An increase in premiums would decrease the amount of taxable wages and salaries and instead increase nontaxable health benefits, which would lower federal revenues.
Still, people living longer could increase revenues through collection of additional payroll and income taxes, but this could also increase expenditures for programs such as Social Security and Medicare. On the other hand, improved health could result in fewer disability claims, reducing expenditures for the Social Security Administration's disability insurance program.
Gene therapies have high upfront costs. For example, Vertex Pharmaceuticals and CRISPR Therapeutics' SCD gene therapy Casgevy (exagamglogene autotemcel) has a list price of $2.2 million, and Bluebird Bio's Lyfgenia (lovotibeglogene autotemcel) has a $3.1 million price tag. Still, these treatments may reduce patients' need for medical care in the future, which could lead to reductions in future healthcare spending in the Medicaid population, the CBO noted. However, the agency cautioned that these savings may take a while to become apparent.
"Offsetting savings from curative or preventive therapies, if they occur, are often realized much later, as the need for ongoing care is averted," it wrote. "The timing of upfront costs and future offsetting savings has implications for the Congressional Budget Office's assessment of the budgetary effects of health interventions, especially if costs occur within the 10-year projection period but savings are realized after that period ends."