Who needs longer tolvaptan treatment? An interim analysis from the Samsca post-marketing surveillance in heart faiLurE (SMILE study)

The vasopressin receptor 2 (V2) receptor antagonist tolvaptan is an aquaretic agent that has been approved for heart failure patients with volume overload in Japan. In this study (SMILE study), we investigated patient characteristics and effectiveness in both a 14 days and shorter treated group (14DS) and 15 days and longer treated group (15DL). The results showed that the patients in the 15DL group had low cardiac output with intensive diuretic administration (ie, diuretic resistance). The congestive symptoms were greatly improved within 14 days of treatment in both the 14DS and 15DL groups. Further improvements in lower limb edema, pulmonary congestion, dyspnea, third sound, and rales after 2 weeks were statistically significant in the 15DL group, but the amount of improvement was subtle and the 15DL group might have consisted of a considerable number of “non-responders”. Therefore, identifying “responders” by biomarkers and conducting a prospective randomized study is required to validate our findings.