Background

β-thalassemia is an inherited, chronic hemolytic anemia caused by mutations in the β-globin gene. Patients with transfusion-dependent β-thalassemia (TDT) require frequent red blood cell (RBC) transfusions to maintain hemoglobin levels, often resulting in long-term complications such as iron overload. In November 2019, luspatercept was approved inn the US  for the treatment of anemia in adult patients with β-thalassemia who require regular RBC transfusions. In the phase III BELIEVE trial, the drug reduced transfusion burden among patients with TD β-thalassemia, but less is known about its impact on real-world healthcare utilization and costs in Medicare FFS populations.

Methods

This retrospective cohort study used Medicare FFS claims data from January 2018 to December 2022 (2021 for Part D), identifying adults with at least one inpatient code or at least two outpatient codes on separate days for β-thalassemia who initiated luspatercept. A post-hoc analysis was also conducted that excluded patients with at least one claim with a myelodysplastic syndrome (MDS) code as that is another approved indication for luspatercept.

Transfusion-dependent patients were identified as patients meeting the eligibility criteria with at least eight claims for RBC transfusion identified using CPT codes within the year pre-index, each of which are no more than six weeks apart. β-thalassemia-related healthcare resource utilization (HCRU) (e.g., inpatient, outpatient, and emergency room visits), pharmacy prescriptions, and costs were evaluated during the 12 months prior to the first observed luspatercept claim and compared with HCRU and costs for up to 12 months post-initiation using paired t-tests.  Given the observational design and reliance on administrative claims, results cannot determine causality and should be considered within the context of the small sample size.

Findings

Thirty-seven patients were identified as eligible for the TDT cohort. An analysis of their findings revealed the following:

• Inpatient HCRU and Costs: No significant difference in β-thalassemia-related  hospitalizations or inpatient costs pre- versus  post-luspatercept initiation.
• Outpatient HCRU and Costs: No significant difference in β-thalassemia-related outpatient visits but significant increase in β-thalassemia-related outpatient visit costs pre- versus  post-luspatercept initiation.
• Transfusion Utilization and Costs: Significant reduction in transfusion visits, but no significant difference in transfusion-related costs pre- versus post-luspatercept initiation.
• Other HCRU and Costs: No significant differences in any prescriptions or iron chelation therapy use or costs pre- versus  post-luspatercept initiation

A post-hoc analysis excluding TDT patients who had any claim for MDS retained 29 patients with TDT. Results among this sample were generally consistent with the primary results. However, there was no significant difference in transfusion visits, but there was a significant increase in transfusion-related costs pre-versus post-luspatercept initiation in this post-hoc cohort.

Implications

For Medicare FFS patients with TD β-thalassemia, luspatercept initiation did not correspond with measurable reductions in β-thalassemia-related inpatient or outpatient HCRU. A reduction in transfusion visits was noted in the cohort of patients prior to excluding those with MDS codes, although no difference was observed when removing patients who could have been receiving luspatercept for approved indications other than TD β-thalassemia. Further research using adjusted analyses or longer follow-up, or achieving larger sample sizes, could clarify whether particular patient groups benefit differently in terms of economic outcomes.

This research was conducted in collaboration with ThermoFisher Scientific.