Longer-term cardiac safety and outcomes of dose dense (dd) doxorubicin and cyclophosphamide (AC) followed by paclitaxel (T) and trastuzumab (H) with and without lapatinib (L) in patients (pts) with early breast cancer (BC).

Abstract

630 Background: The addition of H to chemotherapy has improved outcomes in HER2-positive early BC. This approach is associated with (w/) an increased risk (<4%) of congestive heart failure (CHF). At a median f/u of 36 months, the addition of anti-HER2 Rx to dose-dense (every 2 weeks) anthracycline-taxane therapy (Rx) was not associated with excess cardiotoxicity. Here we report the incidence of NYHA Class III/IV CHF in 2 phase II studies with longer follow-up. Methods: We conducted a retrospective review of pts w/ HER2 + early stage BC treated at MSKCC and DF/HCC on two trials: In trial A - pts received dd AC (60/600 mg/m2) x 4 → T (175mg/m2) x 4 (w/ pegfilgrastim) w/ H x 1 year. Trial B differed w/ use of weekly T (80mg/m2) x 12 and the addition of L (1000mg orally daily) x 1 year. In both trials, H was begun after completion of AC and concurrent with T. Left ventricular ejection fraction (LVEF) was prospectively assessed by multi-gated acquisition scan serially throughout Rx. Results: Trial A enrolled 70 pts and Trial B enrolled 95 pts w/ the median age of 46 years (range 27-73 years). Overall, the 5-year distant disease-free survival (DDFS) for trials A and B is 92% (95%Cl; 83-97%) and 89% (95%CI; 81-94%), respectively. The baseline median LVEF was 68% (range 52-81%). In total, 28 of 165 (17%) pts had pre-existing hypertension. Now at a median follow-up of 84 and 57 months respectively, only one (1.4%, 95%CI; 1.36-7.7%) and 4 (4.2%, 95%CI; 4.2-10.4%) pts developed CHF. Since our earlier report, 1 additional CHF event occurred (Trial B) at month 44. Conclusions: Longer follow-up of these 2 studies demonstrate that dd AC → TH with or without L is associated w/ a low risk of CHF. This is consistent w/ the long-term cardiac toxicity reported from the randomized phase III studies of H w/ conventionally scheduled anthracycline-based regimens (with or without taxanes). DDFS outcomes are also encouraging. Clinical trial information: NCT00482391.