Cardiac toxicity events in the PHARE trial, an adjuvant trastuzumab randomised phase III study

Abstract

Background: This article reports, the cardiac toxicity according to 6- versus 12-month durations of adjuvant trastuzumab in PHARE randomised trial (NCT00381901).

Patients and methods: Cardiac follow-up and Left Ventricular Ejection Fraction (LVEF) assessment by echocardiography or multigated acquisition scan were performed every 3 months while patients received trastuzumab and after completion of treatment over the first 2 years and every 6 months afterwards. The primary cardiac end-point was Cardiac Heart Failure (CHF) defined as New York Heart Association (NYHA) class III or IV. The secondary cardiac end-points were: cardiac events, cardiac dysfunctions defined by NYHA class I and II; LVEF decreases, cardiac recoveries. The cardiac subcommittee reviewed cardiac events and assessed if patients had favourable outcomes or not on the basis of trends from LVEF measurements.

Results: Among 3380 patients the cardiac dysfunction assessment included 14,055 and 13,218 LVEF measurements in the 12- and 6-month arms. The overall incidences of CHF were 0.65% (11/1690) and 0.53% (9/1690) in the 12 and 6 month arms, respectively (p>0.05). Cardiac dysfunction occurred in 5.9% (100/1690) and 3.4% (58/1690) of patients in the 12 and 6 month arms, respectively (p=0.001). Recoveries were observed for the majority patients and 0.79% (27/3380) of patients experienced an unfavourable cardiac outcome.

Conclusion: PHARE confirm that the incidence of cardiac end-points remains low and mostly reversible after trastuzumab. Identification at baseline of cardiac risk categories of patients should be of interest to provide an optimal adaptation of adjuvant modalities and a shorter duration might be an option.

Keywords: Adjuvant trastuzumab; Breast cancer; Cardiac Heart Failure; Cardiotoxicity; Randomised trial.