Real-world characteristics and treatment patterns of patients with myelodysplastic syndromes treated with luspatercept in Puerto Rico

Abstract Background: Myelodysplastic syndromes (MDS) are a rare heterogenous group of hematopoietic stem cell malignancies. Anemia is the most common symptom of MDS, and medications such as erythropoiesis-stimulating agents (ESAs) are frequently used to increase red blood cell (RBC) production. However, >50% of patients with MDS do not respond to ESA treatment. The incidence of MDS in the United States is estimated to be 3.4/100,000 people (SEER Incidence Data, 2020), yet there is limited to no evidence supporting the real-world use of luspatercept among patients with MDS in Puerto Rico. Herein, we assessed real-world demographic characteristics and treatment patterns among patients with MDS receiving luspatercept in Puerto Rico, as well as baseline and post-luspatercept RBC transfusion burden (TB). Methods: This retrospective observational claims study included patients in Puerto Rico from the FARO claims database with a confirmed MDS diagnosis (≥2 outpatient or ≥1 inpatient claims with Medicare and commercial insurance) from May 2020 to December 2023. Patients had ≥1 claim for luspatercept treatment during the patient identification period, with ≥6 months of clinical activity prior to the index date (first observed luspatercept claim) and ≥6 months of postindex clinical activity. Dose escalations were defined as ≥2 consecutive claims of luspatercept at a higher dose than the dosage received on the index date, at any time over the observation period. Does reductions were defined as a claim of luspatercept at a lower dose than the previous dose received. RBC TB was defined as the average number of unique dates with a claim for RBC TB per 8-week period. Transfusion dependency was defined as patients requiring ≥1 transfusion in a rolling 8-week period (from the index date to the end of clinical activity or data availability). Results: Overall, 156 patients were included in the analysis. Mean patient age was 77.4 years at MDS diagnosis and 79.6 years at luspatercept initiation. Most patients were male (55.1%) and had Medicare coverage (92.3%). At index, 91.7% of the patients were transfusion independent and 8.3% were transfusion dependent. Median duration of follow-up was 13 months. Mean time from MDS diagnosis to luspatercept initiation, among patients diagnosed after FDA approval (April 2020; n=92), was 10.6 months. 62.8% of patients had received other treatments for MDS prior to luspatercept, with ESAs being the most commonly prescribed. When assessing treatment patterns, patients remained on luspatercept treatment for a mean of 7.2 months. Most patients had a dose modification during the study period; 65.4% had dose escalations, and 53.2% of patients had 1 dose reduction. In all, 45.5% of patients switched from luspatercept to an alternative treatment, most commonly ESAs (21.2%) or hypomethylating agents (10.9%), with some switching multiple times. The study was limited by a lack of information regarding why patients switched to other treatments. Post-luspatercept treatment, there was a reduction in TB, with 76.9% of patients who were TD at index becoming transfusion independent after initiating luspatercept. Conclusions: To our knowledge, these retrospective claims data provide the first insight into patient characteristics and patterns of use for luspatercept in Puerto Rico. Future studies will aim to understand treatment outcomes and health care resource utilization among patients with MDS treated with luspatercept in Puerto Rico. Ultimately, understanding the real-world use of luspatercept may help optimize therapeutic interventions to improve patient outcomes.