Comparison of Radiation With or Without Concurrent Trastuzumab for HER2-Positive Ductal Carcinoma In Situ Resected by Lumpectomy: A Phase III Clinical Trial.

PURPOSE: Preclinical studies report that trastuzumab (T) can boost radiotherapy (RT) effectiveness. The primary aim of the B-43 trial was to assess the efficacy of RT alone vs concurrent RT plus T in preventing recurrence of ipsilateral breast cancer (IBTR) in women with ductal carcinoma in situ (DCIS). PATIENTS AND METHODS: Eligibility: Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1, DCIS resected by lumpectomy, known estrogen receptor (ER) and/or progesterone receptor (PgR), and human epidermal growth factor receptor 2 (HER2) status by centralized testing. Whole-breast RT was given concurrently with T. Stratification was by menopausal status, adjuvant endocrine therapy plan, and nuclear grade. Definitive intent-to-treat primary analysis was to be conducted when either 163 IBTR events occurred or all accrued patients were on study ≥ 5 years. RESULTS: There were 2,014 participants who were randomly assigned. Median follow-up time as of December 31, 2019, was 79.2 months. At primary definitive analysis, 114 IBTR events occurred: RT arm, 63 and RT plus T arm, 51 (hazard ratio [HR], 0.81; 95% CI, 0.56 to 1.17; P value = .26). There were 34 who were invasive: RT arm, 18 and RT plus T arm, 20 (HR, 1.11; 95% CI, 0.59 to 2.10; P value = .71). Seventy-six were DCIS: RT arm, 45 and RT plus T arm, 31 (HR, 0.68; 95% CI, 0.43 to 1.08; P value = .11). Annual IBTR event rates were: RT arm, 0.99%/y and RT plus T arm, 0.79%/y. The study did not reach the 163 protocol-specified events, so the definitive analysis was triggered by all patients having been on study for ≥ 5 years. CONCLUSION: Addition of T to RT did not achieve the objective of 36% reduction in IBTR rate but did achieve a modest but statistically nonsignificant reduction of 19%. Nonetheless, this trial had negative results. Further exploration of RT plus T is needed in HER2-positive DCIS before its routine delivery in patients with DCIS resected by lumpectomy.

NSABP B-47/NRG Oncology Phase III Randomized Trial Comparing Adjuvant Chemotherapy With or Without Trastuzumab in High-Risk Invasive Breast Cancer Negative for HER2 by FISH and With IHC 1+ or 2.

PURPOSE: Adjuvant trastuzumab reduces invasive breast cancer (IBC) recurrence and risk for death in patients with HER2-amplified or overexpressing IBC. A subset of patients in the landmark trastuzumab adjuvant trials who originally tested HER2-positive but were HER2-negative by central HER2 testing appeared to possibly benefit from trastuzumab. The objective for the NSABP B-47 trial was to determine whether the addition of trastuzumab to adjuvant chemotherapy (CRx) would improve invasive disease-free survival (IDFS) in patients with HER2-negative breast cancer. PATIENTS AND METHODS: A total of 3,270 women with high-risk primary IBC were randomly assigned to CRx with or without 1 year of trastuzumab. Eligibility criteria included immunohistochemistry (IHC) score 1+ or 2+ with fluorescence in situ hybridization ratio (FISH) < 2.0 or, if ratio was not performed, HER2 gene copy number < 4.0. CRx was either docetaxel plus cyclophosphamide or doxorubicin and cyclophosphamide followed by weekly paclitaxel for 12 weeks. RESULTS: At a median follow-up of 46 months, the addition of trastuzumab to CRx did not improve IDFS (5-year IDFS: 89.8% with CRx plus trastuzumab [CRxT] v 89.2% with CRx alone; hazard ratio [HR], 0.98; 95% CI, 0.76 to 1.25; P = .85). These findings did not differ by level of HER2 IHC expression, lymph node involvement, or hormone-receptor status. For distant recurrence-free interval, 5-year estimates were 92.7% with CRxT compared with 93.6% for CRx alone (HR, 1.10; 95% CI, 0.81 to 1.50; P = .55) and for overall survival (OS) were 94.8% with CRxT and 96.3% in CRx alone (HR, 1.33; 95% CI, 0.90 to 1.95; P = .15). There were no unexpected toxicities from the addition of trastuzumab to CRx. CONCLUSION: The addition of trastuzumab to CRx did not improve IDFS, distant recurrence-free interval, or OS in women with non-HER2-overexpressing IBC. Trastuzumab does not benefit women without IHC 3+ or FISH ratio-amplified breast cancer.

Chemotherapy for isolated locoregional recurrence of breast cancer (CALOR): a randomised trial.

BACKGROUND: Patients with isolated locoregional recurrences (ILRR) of breast cancer have a high risk of distant metastasis and death from breast cancer. We aimed to establish whether adjuvant chemotherapy improves the outcome of such patients. METHODS: The CALOR trial was a pragmatic, open-label, randomised trial that accrued patients with histologically proven and completely excised ILRR after unilateral breast cancer who had undergone a mastectomy or lumpectomy with clear surgical margins. Eligible patients were enrolled from hospitals worldwide and were centrally randomised (1:1) to chemotherapy (type selected by the investigator; multidrug for at least four courses recommended) or no chemotherapy, using permuted blocks, and stratified by previous chemotherapy, oestrogen-receptor and progesterone-receptor status, and location of ILRR. Patients with oestrogen-receptor-positive ILRR received adjuvant endocrine therapy, radiation therapy was mandated for patients with microscopically involved surgical margins, and anti-HER2 therapy was optional. The primary endpoint was disease-free survival. All analyses were by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00074152. FINDINGS: From Aug 22, 2003, to Jan 31, 2010, 85 patients were randomly assigned to receive chemotherapy and 77 were assigned to no chemotherapy. At a median follow-up of 4·9 years (IQR 3·6-6 ·0), 24 (28%) patients had disease-free survival events in the chemotherapy group compared with 34 (44%) in the no chemotherapy group. 5-year disease-free survival was 69% (95% CI 56-79) with chemotherapy versus 57% (44-67) without chemotherapy (hazard ratio 0·59 [95% CI 0·35-0·99]; p=0·046). Adjuvant chemotherapy was significantly more effective for women with oestrogen-receptor-negative ILRR (pinteraction=0·046), but analyses of disease-free survival according to the oestrogen-receptor status of the primary tumour were not statistically significant (pinteraction=0·43). Of the 81 patients who received chemotherapy, 12 (15%) had serious adverse events. The most common adverse events were neutropenia, febrile neutropenia, and intestinal infection. INTERPRETATION: Adjuvant chemotherapy should be recommended for patients with completely resected ILRR of breast cancer, especially if the recurrence is oestrogen-receptor negative. FUNDING: US Department of Health and Human Services, Swiss Group for Clinical Cancer Research (SAKK), Frontier Science and Technology Research Foundation, Australian and New Zealand Breast Cancer Trials Group, Swedish Cancer Society, Oncosuisse, Cancer Association of South Africa, Foundation for Clinical Research of Eastern Switzerland (OSKK), Grupo Español de Investigación en Cáncer de Mama (GEICAM), and the Dutch Breast Cancer Trialists' Group (BOOG).

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.

Drug development: neoadjuvant opportunities in breast cancer.

Preoperative therapy allows for a higher rate of breast conserving surgery and has been shown equivalent to adjuvant therapy. Preoperative therapy provides an opportunity to obtain insights into breast cancer biology and to accelerate the evaluation of new therapies. Clinical trials have shown that women who achieve a pathologic complete response (pCR) have substantially improved outcomes compared with those who do not achieve a pCR. The U.S. Food and Drug Administration (FDA) meta-analysis demonstrated that the association of pCR and long-term outcomes is greater in women with aggressive breast cancer subtypes. In patients with HER2+ breast cancer, the addition of trastuzumab to chemotherapy in the neoadjuvant setting has doubled pCR and correlated with improved outcomes. Clinical trials will evaluate tailoring the use of radiation therapy in patients who have received neoadjuvant therapy. Trials have established neoadjuvant endocrine therapy as a valid treatment and research option for ER-rich breast cancer. The neoadjuvant setting allows for evaluation of endocrine therapies in combination with newer targeted therapies in the appropriate patient populations. The neoadjuvant setting provides opportunity to accelerate the evaluation of new agents, improve pCR rates, and identify predictive biomarkers for response. This setting provides the opportunity for screening new agents in combination with chemotherapy while obtaining serial biopsies to understand biology of response and resistance. Although current standard therapies provide substantial benefits for patients with a pCR, patients with residual disease are at substantial risk for disease recurrence. New agents are being evaluated in patients with high-risk residual disease following standard treatment regimens.