Abstract 4358519: Combination Therapy with SGLT2 Inhibitors and Tafamidis Improves Outcomes More Than Tafamidis Alone in ATTR Cardiac Amyloidosis

Background: Among cardiac amyloidosis subtypes, transthyretin cardiac amyloidosis (ATTR) has gained increased recognition with the development of disease-specific therapies. Tafamidis, a selective oral stabilizer of the transthyretin tetramer, has emerged as an effective treatment. In the broader heart failure landscape, sodium-glucose cotransporter 2 inhibitors (SGLT2i) have become cornerstone therapies across the ejection fraction spectrum, improving survival and reducing hospitalizations in both HFrEF and HFpEF. However, the clinical benefit of combining Tafamidis with SGLT2i in ATTR remains largely unknown. Hypothesis: Combination therapy with Tafamidis and SGLT2i provides added clinical benefits in patients with ATTR cardiac amyloidosis. Methods: This retrospective cohort study included adults with confirmed ATTR cardiac amyloidosis diagnosed via 99mTc-pyrophosphate scintigraphy and treated with Tafamidis alone or with an SGLT2i across three academic centers from January 2019 to February 2025. Baseline characteristics and outcomes were collected from medical records. The primary endpoint was all-cause mortality. Kaplan-Meier analysis and multivariable Cox proportional hazards modeling were used, adjusting for age, sex, atrial fibrillation, diabetes, hypertension, hyperlipidemia, ejection fraction (EF), and glomerular filtration rate (GFR). Results: Among the 1,211 patients included in the 3-year follow-up analysis,946 received Tafamidis monotherapy and 265 received a combination of Tafamidis and an SGLT2i. The mean age of the cohort was 71.9 years (SD ±9.4), and 87.3% were male. A total of 142 mortality events occurred, with a higher cumulative mortality rate observed in the tafamidis-only group (16.3%) compared to the combination group (9.4%) (log-rank p = 0.042). In the multivariable Cox proportional hazards model, combination therapy with Tafamidis and an SGLT2i was independently associated with a significantly lower risk of mortality (adjusted HR =0.576, 95% CI:0.334–0.992, p =0.04). Additionally, increasing age (HR =1.049, 95% CI:1.024–1.074, p < 0.001) was associated with higher mortality, while EF(HR =0.971, 95% CI:0.958–0.984, p< 0.001) and GFR (HR =0.975, 95% CI:0.965-0.985, p< 0.001) were with lower mortality. Conclusion: Combination therapy with Tafamidis and SGLT2i was associated with improved survival compared to Tafamidis alone in ATTR cardiac amyloidosis. Further prospective trials are needed to validate these findings and guide therapy optimization.