A recent analysis of real-world data sheds light on the optimal timing for selexipag initiation in patients with pulmonary arterial hypertension (PAH). The study, utilizing data from a large US payer dataset, suggests that early exposure to selexipag, specifically within six months of starting treatment with an endothelin receptor antagonist (ERA) and a phosphodiesterase type 5 (PDE5) inhibitor, is associated with improved outcomes.
The research, led by Burger et al, examined data from over 2,900 patients recently prescribed a PDE5 inhibitor and an endothelin antagonist. The findings indicated that patients who added oral selexipag early in their treatment course experienced a decreased risk for all-cause hospitalization, PAH-related hospitalization, and PAH-related disease progression, defined as initiation of parenteral therapies, PAH-related hospitalization, death, transplant, or septostomy.
Early vs. Late Selexipag Exposure
The study revealed a critical time-dependent effect of selexipag. Similar to post hoc analyses of the GRIPHON trial, the benefit of selexipag was most evident when introduced early, ideally within six months of initiating therapy with an ERA and a PDE5 inhibitor. In contrast, less benefit was observed when selexipag was added after 12 months. This highlights the importance of considering early intervention with selexipag in appropriate patients.
Real-World Data vs. Clinical Trials
An important aspect of the study is its reflection of real-world clinical practice. The authors note that the study cohort represented an older group of patients with a higher number of comorbidities compared to those enrolled in pivotal selexipag trials. This suggests that the use of PAH therapies in clinical practice may not always align with the populations in which the benefits of PAH-directed therapy have been demonstrated in clinical trials.
Limitations and Considerations
Despite the valuable insights, the authors acknowledge several limitations. The study lacked access to crucial clinical data, such as functional capacity assessments (walk distance and New York Heart Association classification), symptom evaluations, and laboratory data (e.g., N-terminal pro–B-type natriuretic peptide and echocardiogram data). The absence of this information may have led to the omission of important prognostic variables and covariates. Furthermore, only 36% of patients had a recorded cardiac catheterization within six months prior to diagnosis, raising concerns about the accuracy of PAH diagnoses within the cohort.
Expert Commentary
"Clinical data are messy, sometimes misleading, and often incomplete," notes John Granton, MD, Division of Respirology, Faculty of Medicine, Toronto General Hospital, University of Toronto, in an accompanying editorial. He emphasizes the importance of considering these limitations when interpreting the study's findings. Granton also raises the question of how sotatercept, a novel therapeutic agent for PAH, will be incorporated into clinical practice relative to other add-on therapies like selexipag.
Implications for Clinical Practice
Despite the limitations, the study provides valuable insights into the role of selexipag in PAH management. The findings underscore the potential benefits of early selexipag initiation in select patients already receiving ERA and PDE5 inhibitor therapy. However, clinicians should carefully consider individual patient characteristics, comorbidities, and disease severity when making treatment decisions. Further research is needed to better define the optimal timing and patient selection criteria for selexipag therapy in PAH.
