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Gene therapy for sickle cell disease could substantially increase life expectancy, but its cost-effectiveness compared to conventional treatment will depend on price

Two NIH-funded models provide detailed estimates of costs and benefits

An analysis funded by the National Heart, Lung, and Blood Institute (NHLBI), part of National Institutes of Health, suggests that compared with the life-long costs of treating sickle cell disease (SCD), a potential one-time gene therapy treatment will significantly reduce morbidity, improve survival, and reduce the cost of care over patients’ lifetimes compared to conventional care. Published in the Annals of Internal Medicine, the study shows the results of two independent computer simulation models to provide the most detailed estimates of upfront and downstream clinical effects, costs, and value-based prices of gene therapy treatments for SCD to date. Both models predicted tremendous health benefits for patients and spillover benefits for caregivers and society in terms of enabling patients to stay in the workforce.  The two models differed in the price where gene therapy would be considered cost-effective. One model found that a price of $1 million is needed, while the other estimated a price below $2 million per patient would be cost-effective. The question of affordability to treat SCD with gene therapy is front-and-center following the U.S. Food and Drug Administration’s approval of the first gene therapies in late 2023. Estimates place the current lifetime cost of medical care for SCD patients using conventional treatments at around $2 million.

The analysis comes on the heels of the U.S. Food and Drug Administration’s approval of the first gene therapies for sickle cell disease in December. The painful and potentially life-threatening genetic condition affects nearly 100,000 people in the United States, more than half of whom are enrolled in Medicaid, Medicare, or both (Centers for Medicaid and Medicare Services or CMS).

“Our main results indicate that if the acquisition cost of a gene therapy for sickle cell disease is less than $2 million, the therapy will provide society with an acceptable value,” said corresponding study author Anirban Basu, Ph.D., a professor of health economics at the University of Washington in Seattle and the Director of the Comparative Health Outcomes, Policy, and Economics (CHOICE) Institute. He specializes in research on comparative and cost-effectiveness analysis.

Conventional treatments or common care for sickle cell can include the use of hydroxyurea and other medicines, as well as frequent blood transfusions. However, these treatments are largely temporary and focus on easing the symptoms of the disease, particularly severe pain episodes that are the hallmark of SCD. Bone marrow stem cell transplants, while curative, are limited by a lack of genetically well-matched donors and other challenges.

Researchers have only recently developed genetic therapies for sickle cell, potentially providing longer life expectancy and improved quality of life. They include therapies that boost the production of fetal hemoglobin, a type of oxygen-carrying blood protein present at birth. When increased in adults with SCD, fetal hemoglobin reduces complications associated with the disease, including blockage of the blood vessels that can cause severe pain and organ damage, including stroke. Experts have long estimated that the cost of these therapies will be extremely high initially, but previous studies on the cost have been largely hypothetical.

For the new study, part of the NHLBI’s Cure Sickle Cell Initiative, the researchers developed two independent cost-effectiveness simulation models to explore these real-world costs as well as benefits over a lifetime. They included the University of Washington Model for Economic Analysis of Sickle Cell Cure (UW-MEASURE) and the Fred Hutchinson Institute Sickle Cell Disease Outcomes Research and Economics Model (FH-HISCORE). Both models, which differ slightly in their design, analyzed insurance claims data on individuals with sickle cell disease who were enrolled in Medicaid, Medicare, or both (Centers for Medicaid and Medicare Services or CMS) between 2008 and 2016.

The researchers limited their analysis to CMS data from 4,762 people ages 12 to 38 years (50% female) who were eligible for gene therapy based on current patient selection criteria. Researchers adjusted both models to reflect an average life expectancy for the SCD patient population in general of 51 years, which is much shorter than the average life expectancy for Americans in general, which is about 77 years, according to the Centers for Disease Control and Prevention. The population eligible for gene therapy had more severe disease and an even shorter life expectancy than others with SCD, the researchers noted.

In addition to cost estimates, the models also analyzed the effectiveness of treatments with a focus on health impacts, such as quality of life and life expectancy; and nonmedical impacts, including loss of time and patient productivity, and the impact on the patient’s caregiver and family. Both models were compared to conventional care across the average lifespan of an SCD patient.

The FH-HISCORE model found that any price tag for SCD gene therapy below $1 million is highly cost-effective, while the UW-MEASURE model found that any price below $2 million is highly cost-effective. Collectively, the models suggest that any price below $2 million, while high, could be worth it. But above that, they noted, the confidence that such therapy will deliver an acceptable value for money deteriorates quickly.

In addition to the cost benefits over conventional therapy, both models showed other important advantages to SCD gene therapy, including societal benefits. It could increase life expectancy by 17 years (17.4 for UW-MEASURE and 17 for FH-HISCORE). It would reduce the lifetime number of acute pain crises by 69 or 86 events, respectively, compared to common care. And it could increase prospects for the patient’s long-term employment, as well as offer improvements in their caregiver’s quality of life.

Aside from those perks, said Basu, the price of gene therapy could also get cheaper. “As costs of manufacturing gene therapy products become more streamlined and efficient, it could help bring down the prices of gene therapy,” he said, noting that the exact cost of gene therapy for SCD also depends, in part, on future discussions among policymakers, insurers, and patients, who must balance budgets, affordability, and promote competition across multiple manufacturers of gene therapy.

Study co-author Scott Ramsey, M.D., Ph.D., a researcher, health economist, and director of the Hutchinson Institute for Cancer Outcomes Research at the Fred Hutch Cancer Center in Seattle, noted the importance of looking beyond healthcare costs to fully appreciate the value of SCD gene therapy.

“Ignoring the societal costs of treating sickle cell disease—factors such as impact on a patient’s ability to work and caregiver burden—vastly underestimates the potential benefits of gene therapy, ” he said. “This is ultimately about saving lives.”

To learn more about sickle cell disease, visit

This work was funded by NHLBI’s Cure Sickle Cell initiative under agreements OT3HL152448 and OT3HL151434. For a more complete funding disclosure and list of authors, please see the full research article.

Gene Therapy versus Common Care for Eligible Individuals with Sickle Cell Disease in the United States: A Cost-Effectiveness Analysis. Annals of Internal Medicine.