Stem cell transplant for SCD beats gene therapy on cost: Study
Gene therapy cost needs to drop substantially to become cost-effective
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Stem cell transplant from a partially matched donor is more cost-effective than gene therapy to treat sickle cell disease (SCD), according to a study.
In order for currently available gene therapies to deliver cost effectiveness on par with stem cell transplant, their cost would need to come down by at least 66%, the researchers found.
The study, “Haploidentical transplant, gene therapy, and standard care in sickle cell disease: a cost-effectiveness analysis,” was published in Blood. The National Institutes of Health was among the study’s funders.
“No matter how much we adjusted from base case assumptions or accounted for uncertainty, [stem cell transplant] delivered the best clinical value for cost,” George Goshua, MD, assistant professor at Yale School of Medicine and the study’s senior author, said in a press release from the American Society of Hematology, which publishes Blood.
Cost, access pose barriers to transplant
“Globally, the cost and access to stem cell transplantations are substantial barriers for many,” Goshua said.” The price thresholds suggested in our U.S. and expanded international analyses may help guide local governmental investment for both curative therapies in sickle cell disease.”
SCD is a genetic disorder marked by an abnormal form of hemoglobin, the protein that red blood cells use to carry oxygen through the bloodstream. Standard-of-care treatment for SCD involves hydroxyurea, blood transfusions, and medications for pain management.
Despite standard care, the disease can hamper patients’ quality of life, and the need for lifelong treatment can be burdensome.
Blood cells are made by hematopoietic stem cells (HSCs) in bone marrow. Stem cell transplant and gene therapy have the same goal: to give patients HSCs that can produce healthy or improved forms of hemoglobin, functionally curing the disease.
Stem cell transplant replaces a patient’s HSCs with cells from a healthy donor. Traditional approaches require a donor who is perfectly matched across several immune-related markers, and rely on intensive conditioning regimens — chemotherapy and radiation — to destroy existing cells and make room for the transplanted cells.
An alternative approach called non-myeloablative haploidentical allogeneic hematopoietic stem cell transplantation (NMAC-HID allo-HSCT) has become increasingly common. It uses a donor who is matched for only half of the immune markers instead of all — increasing the pool of potential donors — and less intensive conditioning.
Gene therapy for SCD involves collecting a patient’s HSCs, genetically modifying them in a lab, and then infusing them back into the patient. The two SCD gene therapies currently approved in the U.S. are Lyfgenia (lovotibeglogene autotemcel) and Casgevy (exagamglogene autotemcel). Both use a high-intensity conditioning similar to what’s used in traditional stem cell transplants.
Gene therapies carry hefty list prices: $2.2 million for Casgevy and $3.1 million for Lyfgenia. Stem cell transplant, as a highly complex medical procedure, can also be pricey.
“Gene therapy is an incredible immune innovation, but it comes with an astronomical cost,” Goshua said. “Recent … studies suggest that stem cell transplantation is now safer and more efficacious than before for people living with sickle cell disease, but data on its cost-effectiveness, especially in the era of gene therapy, have been limited.”
To fill this gap, researchers conducted analyses comparing the cost-effectiveness of these approaches and standard care, focusing on costs incurred over a patient’s lifetime.
“From a patient perspective, there are multiple trade-offs across sickle cell treatment options, including differences in eligibility, timing, and a patient’s individual values and preferences,” Goshua said. “From a policy perspective, understanding the cost-effectiveness of all these available treatments can equip governments to make informed, strategic decisions about how to invest in and support the health of their populations living with sickle cell disease.”
Mapping cost-effectiveness
The researchers looked at cost per quality-adjusted life-years (QALYs), a representation of how long and well patients live. For gene therapy, the researchers used Casgevy’s lower list price as the basis for their estimates.
Their models showed that standard care delivered 14.3 QALYs at a cost of $1.22 million. QALYs were higher with NMAC-HID allo-HSCT, at 20.1, and gene therapy, at 22.1. But whereas the cost for NMAC-HID allo-HSCT was similar to standard care, at $1.15 million, gene therapy’s cost was more than twice as high, at $2.75 million.
Based on their models, the researchers estimated that the threshold price of gene therapy in the U.S. relative to NMAC-HID allo-HSCT is somewhere between $627,000 and $740,000 — meaning it would require a 66% to 71% cost reduction.
In less wealthy countries, such as India, Nigeria, and Tanzania where SCD is common, their models showed gene therapy would be cost-effective at prices ranging from $4,200 to $22,000.
The researchers stressed that their models had several limitations, including a lack of substantial long-term data from patients who received gene therapy. They also emphasized that decisions about SCD treatment need to be made on a case-by-case basis, taking each patient’s unique situation into account.
“It is important for individuals living with sickle cell disease to have access to as many treatments as possible; gene therapy may be the best option for many patients, and these data should not be interpreted as reason to deny them coverage,” Goshua said. “Treating physicians must continue to discuss all options with patients in the context of shared patient-physician decision making.”
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