Long-term outcomes of dual vs single HER2-directed neoadjuvant therapy in NSABP B-41.

BACKGROUND: The primary aim of this randomized neoadjuvant trial in operable, HER2-positive breast cancer, was to determine the efficacy on pathologic complete response (pCR) of substituting lapatinib (L) for trastuzumab (T) or adding L to T, in combination with weekly paclitaxel (WP) following AC. Results on pCR were previously reported. Here, we report data on planned secondary endpoints, recurrence-free interval (RFI) post-surgery, and overall survival (OS). METHODS: All patients received standard AC q3 weeks × 4 cycles followed by WP (80 mg/m2) on days 1, 8, and 15, q28 days × 4 cycles. Concurrently with WP, patients received either T (4 mg/kg load, then 2 mg/kg) weekly until surgery, L (1250 mg) daily until surgery, or weekly T plus L (750 mg) daily until surgery. Following surgery, all patients received T to complete 52 weeks of HER2-targeted therapy. 522 of 529 randomized patients had follow-up. Median follow-up was 5.1 years. RESULTS: RFI at 4.5 years was 87.2%, 79.4% (p = 0.34; HR = 1.37; 95% CI 0.80, 2.34), and 89.4% (p = 0.37; HR = 0.70; 0.37, 1.32) for arms T, L, and TL, respectively. The corresponding five-year OS was 94.8%, 89.1% (p = 0.34; HR = 1.46; 0.68, 3.11), and 95.8% (p = 0.25; HR = 0.58; 0.22, 1.51), respectively. Patients with pCR had a much better prognosis, especially in the ER-negative cohort: RFI (HR = 0.23, p < 0.001) and OS (HR = 0.28, p < 0.001). CONCLUSIONS: Although pCR, RFI, and OS were numerically better with the dual combination and less with L, the differences were not statistically significant. However, achievement of pCR again correlated with improved outcomes, especially remarkable in the ER-negative subset. CLINICAL TRIALS REGISTRATION: NCT00486668.

Behavioral and health outcomes from the NRG Oncology/NSABP B-36 trial comparing two different adjuvant therapy regimens for early-stage node-negative breast cancer.

BACKGROUND: The NSABP B-36 compared four cycles of doxorubicin and cyclophosphamide (AC) with six cycles of 5-fluorouracil, epirubicin, and cyclophosphamide (FEC-100) in node-negative early-stage breast cancer. A sub-study within B-36, focusing on symptoms, quality of life (QOL), menstrual history (MH), and cardiac function (CF) was conducted. PATIENTS AND METHODS: Patients completed the QOL questionnaire at baseline, during treatment, and every 6 months through 36 months. FACT-B Trial Outcome Index (TOI), symptom severity, and SF-36 Vitality and Physical Functioning (PF) scales scores were compared between the two groups using a mixed model for repeated measures analysis. MH was collected at baseline and subsequently assessed if menstrual bleeding occurred within 12 months prior to randomization. Post-chemotherapy amenorrhea outcome was examined at 18 months and was defined as lack of menses in the preceding year. Logistic regression was used to test for association of amenorrhea and treatment. CF assessment was done at baseline and 12 months. Correlation analysis was used to address associations between changes in baseline and 12-month PF and concurrent CF changes measured by LVEF. RESULTS: FEC-100 patients had statistically significantly lower TOI scores during chemotherapy (P = 0.02) and at 6 months (P < 0.001); lower Vitality score at 6 months (P < 0.01), and lower PF score during the first year than AC patients. There were no statistically significant QOL score differences between the two groups beyond 12 months. No significant differences in symptom severity between the two groups were observed. Rates of amenorrhea were significantly different between FEC-100 and AC (67.4% vs. 59.1%, P < 0.001). There was no association between changes in LVEF and PF (P = 0.38). CONCLUSIONS: Statistically significant QOL differences between the two groups favored AC; however, the magnitude was small and unlikely to be clinically meaningful. There was a clinical and statistically significant difference in risk for amenorrhea, favoring AC. TRIAL REGISTRY: NCT00087178; Date of registration: 07/08/2004.

Lapatinib as a component of neoadjuvant therapy for HER2-positive operable breast cancer (NSABP protocol B-41): an open-label, randomised phase 3 trial.

BACKGROUND: We studied the effect on tumour response to neoadjuvant therapy of the substitution of lapatinib for trastuzumab in combination with weekly paclitaxel after doxorubicin plus cyclophosphamide treatment, and of the addition of lapatinib and trastuzumab combined after doxorubicin plus cyclophosphamide treatment in patients with HER2-positive operable breast cancer to determine whether there would be a benefit of dual HER2 blockade in these patients. METHODS: For this open-label, randomised phase 3 trial we recruited women aged 18 years or older with an ECOG performance status of 0 or 1 with operable HER2-positive breast cancer. Each received four cycles of standard doxorubicin 60 mg/m(2) and cyclophosphamide 600 mg/m(2) intravenously on day 1 every 3 weeks followed by four cycles of weekly paclitaxel (80 mg/m(2)) intravenously on days 1, 8, and 15, every 4 weeks. Concurrently with weekly paclitaxel, patients received either trastuzumab (4 mg/kg load, then 2 mg/kg intravenously) weekly until surgery, lapatinib (1250 mg orally) daily until surgery, or weekly trastuzumab plus lapatinib (750 mg orally) daily until surgery. After surgery, all patients received trastuzumab to complete 52 weeks of HER2-targeted therapy. Randomisation (ratio 1:1:1) was done centrally with stratification by clinical tumour size, clinical nodal status, hormone-receptor status, and age. The primary endpoint was the pathological complete response in the breast, and analysis was performed on an intention-to-treat population. FINDINGS: Patient accrual started on July 16, 2007, and was completed on June 30, 2011; 529 women were enrolled in the trial. 519 patients had their pathological response determined. Breast pathological complete response was noted in 93 (52·5%, 95% CI 44·9-59·5) of 177 patients in the trastuzumab group, 91 (53·2%, 45·4-60·3) of 171 patients in the lapatinib group (p=0·9852); and 106 (62·0%, 54·3-68·8) of 171 patients in the combination group (p=0·095). The most common grade 3 and 4 toxic effects were neutropenia (29 [16%] patients in the trastuzumab group [grade 4 in five patients (3%), 28 [16%] in the lapatinib group [grade 4 in eight patients (5%)], and 29 [17%] in the combination group [grade 4 in nine patients (5%)]) and grade 3 diarrhoea (four [2%] patients in the trastuzumab group, 35 [20%] in the lapatinib group, and 46 [27%] in the combination group; p<0·0001). Symptomatic congestive heart failure defined as New York Heart Association Class III or IV events occurred in seven (4%) patients in the trastuzumab group, seven (4%) in the lapatinib group, and one (<1%) in the combination group; p=0·185). INTERPRETATION: Substitution of lapatinib for trastuzumab in combination with chemotherapy resulted in similar high percentages of pathological complete response. Combined HER2-targeted therapy produced a numerically but insignificantly higher pathological complete response percentage than single-agent HER2-directed therapy; these findings are consistent with results from other studies. Trials are being undertaken to further assess these findings in the adjuvant setting.