Neoadjuvant dose-dense sequential biweekly epirubicin and cyclophosphamide followed by docetaxel and trastuzumab for HER2+ operable breast cancer

Abstract

595 Background: Neoadjuvant (Neo) chemotherapy (CT) with trastuzumab (H) improves pathologic complete response (pCR) rate for HER2+ breast cancer. Dose-dense regimens improve outcome in the adjuvant setting but have not been fully evaluated as preoperative therapy. We designed this regimen to utilize full doses of active agents including docetaxel (T) and H in a novel biweekly schedule to explore efficacy and safety. Methods: Patients (pts) with biopsy proven, clinical stage IIA-IIIC, noninflammatory breast cancer were eligible. HER2+ by FISH was determined locally. CT consisted of epirubicin (E) 100 mg/m2 and cyclophosphamide (C) 600 mg/m2 Q 14 days x 4 followed by T 75 mg/m2 and H 6 mg/kg loading dose, then 4 mg/kg Q 14 days x 4, all with pegfilgrastim support. Surgery was scheduled 20–24 weeks from start after a fifth cycle of H 4mg/kg. EF was measured prior to CT, after EC, after TH and at 6, 12 and 24 months after surgery. Additional adjuvant H to complete 1 year of therapy by conventional schedule was recommended after surgery. The primary endpoint was pCR for invasive cancer in breast and lymph nodes. Results: 30 pts were enrolled at 5 centers: median age was 50.1 (range, 31–72); ethnicity African-American 14, Caucasian 14, other 2; clinical stage IIA, 14, IIB, 4, IIIA, 7, IIIB/C, 5; ER+ 18, PR+ 14; grade 3, 21 and grade 2, 8. Twenty eight pts were evaluable for pathologic response- 2 withdrew before completing treatment, 1 for toxicity. Dose delivery on schedule was >95% for all drugs. Clinical response prior to surgery was cCR 20; cPR 5; and stable 2 pts. Pathologic response: pCR 16 (57%) including 4 with residual DCIS only; 9 pPR, and 2 stable. Mean EF was 63.1 (range, 51–81) before treatment, 62.4 (49–75) after EC and 58.3 (35–74) after TH. Two pts had EF <50% during Neo, one with clinical CHF and 1 additional pt developed CHF during adjuvant single agent H. Both pts had symptomatic improvement with cessation of H. Adverse events were generally mild with 14 grade 3 AEs including 3 episodes of dyspnea and no grade 3 skin toxicity or any grade 4 toxicity noted. Conclusions: Sequential Neo dose-dense Q 14 day EC followed by Q 14 day TH yields a high pCR rate in HER2+ breast cancer with acceptable toxicity profile and no new safety signals noted. No significant financial relationships to disclose.