Summary Background Clinical trials have shown that trastuzumab, a recombinant monoclonal antibody against HER2 receptor, significantly improves overall survival and disease-free survival in women ...with HER2-positive early breast cancer, but long-term follow-up data are needed. We report the results of comparing observation with two durations of trastuzumab treatment at a median follow-up of 11 years, for patients enrolled in the HERA (HERceptin Adjuvant) trial. Methods HERA (BIG 1-01) is an international, multicentre, open-label, phase 3 randomised trial of 5102 women with HER2-positive early breast cancer, who were enrolled from hospitals in 39 countries between Dec 7, 2001, and June 20, 2005. After completion of all primary therapy (including, surgery, chemotherapy, and radiotherapy as indicated), patients were randomly assigned (1:1:1) to receive trastuzumab for 1 year (once at 8 mg/kg of bodyweight intravenously, then 6 mg/kg once every 3 weeks) or for 2 years (with the same dose schedule), or to the observation group. Primary endpoint is disease-free survival, and analyses are in the intention-to-treat population. Hazard ratios (HRs) were estimated from Cox models, and survival curves were estimated by the Kaplan-Meier method. Comparison of 2 years versus 1 year of trastuzumab is based on 366-day landmark analyses. This study is registered with ClinicalTrials.gov ( NCT00045032 ). Findings Of the 5102 women randomly assigned in the HERA trial, three patients had no evidence of having provided written informed consent to participate. We followed up the intention-to-treat population of 5099 patients (1697 in observation, 1702 in 1-year trastuzumab, and 1700 in 2-years trastuzumab groups). After a median follow-up of 11 years (IQR 10·09–11·53), random assignment to 1 year of trastuzumab significantly reduced the risk of a disease-free survival event (HR 0·76, 95% CI 0·68–0·86) and death (0·74, 0·64–0·86) compared with observation. 2 years of adjuvant trastuzumab did not improve disease free-survival outcomes compared with 1 year of this drug (HR 1·02, 95% CI 0·89–1·17). Estimates of 10-year disease-free survival were 63% for observation, 69% for 1 year of trastuzumab, and 69% for 2 years of trastuzumab. 884 (52%) patients assigned to the observation group selectively crossed over to receive trastuzumab. Cardiac toxicity remained low in all groups and occurred mostly during the treatment phase. The incidence of secondary cardiac endpoints was 122 (7·3%) in the 2-years trastuzumab group, 74 (4·4%) in the 1-year trastuzumab group, and 15 (0·9%) in the observation group. Interpretation 1 year of adjuvant trastuzumab after chemotherapy for patients with HER2-positive early breast cancer significantly improves long-term disease-free survival, compared with observation. 2 years of trastuzumab had no additional benefit. Funding F Hoffmann-La Roche (Roche).
To update the previous report from 2 randomized clinical trials, now with a median follow-up of 16 years, to analyze the effect of radiation therapy timing on local failure and disease-free survival.
...From July 1986 to April 1993, International Breast Cancer Study Group trial VI randomly assigned 1475 pre-/perimenopausal women with node-positive breast cancer to receive 3 or 6 cycles of initial chemotherapy (CT). International Breast Cancer Study Group trial VII randomly assigned 1212 postmenopausal women with node-positive breast cancer to receive tamoxifen for 5 years, or tamoxifen for 5 years with 3 early cycles of initial CT. For patients who received breast-conserving surgery (BCS), radiation therapy (RT) was delayed until initial CT was completed; 4 or 7 months after BCS for trial VI and 2 or 4 months for trial VII. We compared RT timing groups among 433 patients on trial VI and 285 patients on trial VII who received BCS plus RT. Endpoints were local failure, regional/distant failure, and disease-free survival (DFS).
Among pre-/perimenopausal patients there were no significant differences in disease-related outcomes. The 15-year DFS was 48.2% in the group allocated 3 months initial CT and 44.9% in the group allocated 6 months initial CT (hazard ratio HR 1.12; 95% confidence interval CI 0.87-1.45). Among postmenopausal patients, the 15-year DFS was 46.1% in the no-initial-CT group and 43.3% in the group allocated 3 months initial CT (HR 1.11; 95% CI 0.82-1.51). Corresponding HRs for local failures were 0.94 (95% CI 0.61-1.46) in trial VI and 1.51 (95% CI 0.77-2.97) in trial VII. For regional/distant failures, the respective HRs were 1.15 (95% CI 0.80-1.63) and 1.08 (95% CI 0.69-1.68).
This study confirms that, after more than 15 years of follow-up, it is reasonable to delay radiation therapy until after the completion of standard CT.
Summary Background Findings from the randomised phase 3 NeoALTTO trial in women with HER2-positive early breast cancer showed that the combination of lapatinib and trastuzumab significantly improved ...rates of pathological complete response compared with either drug alone. Here, we report data for the prespecified secondary endpoints of event-free and overall survival, and assess the association between these outcomes and pathological complete response. Methods We enrolled women with HER2-positive early breast cancer and randomly assigned them to receive oral lapatinib (1500 mg), intravenous trastuzumab (4 mg/kg loading dose followed by 2 mg/kg), or lapatinib (1000 mg) plus trastuzumab (same dose as for single agent) in combination for 6 weeks, followed by an additional 12 weeks of the assigned anti-HER2 therapy in combination with weekly paclitaxel (80 mg/m2 ). Definitive surgery was done 4 weeks after the last dose of paclitaxel. After surgery, women received three cycles of FEC (fluorouracil 500 mg/m2 plus epirubicin 100 mg/m2 plus cyclophosphamide 500 mg/m2 ) given intravenously every 3 weeks, followed by 34 weeks of the same assigned neoadjuvant anti-HER2 therapy. The primary endpoint was pathological complete response. Secondary endpoints included event-free and overall survival (intention-to-treat analysis), and the association between pathological complete response and event-free or overall survival (analysed by landmark analysis at 30 weeks after randomisation). Follow-up is ongoing, and the trial is registered with ClinicalTrials.gov , number NCT00553358. Findings 455 patients were enrolled: 154 (34%) were assigned to the lapatinib group, 149 (33%) to the trastuzumab group, and 152 (33%) to the lapatinib plus trastuzumab group. At an event follow-up of 3·77 years (IQR 3·50–4·22), 3-year event-free survival was 78% (95% CI 70–84) in the lapatinib group, 76% (68–82) in the trastuzumab group, and 84% (77–89) in the combination group. Event-free survival did not differ between the lapatinib and trastuzumab groups (HR 1·06, 95% CI 0·66–1·69, p=0·81), nor between the combination and trastuzumab groups (0·78, 0·47–1·28, p=0·33). Median survival follow-up was 3·84 years (IQR 3·60–4·24), and 3-year overall survival was 93% (95% CI 87–96) for lapatinib, 90% (84–94) for trastuzumab, and 95% (90–98) for combination therapy. Overall survival did not significantly differ between the lapatinib and trastuzumab groups (HR 0·86, 95% CI 0·45–1·63, p=0·65), nor between the combination and trastuzumab groups (0·62, 0·30–1·25, p=0·19). Landmark analyses showed that 3-year event-free survival was significantly improved for women who achieved pathological complete response compared with those who did not (HR 0·38, 95% CI 0·22–0·63, p=0·0003), as was 3-year overall survival (0·35, 0·15–0·70, p=0·005). Adverse events occurred in 149 (99%) patients receiving lapatinib, 142 (96%) patients receiving trastuzumab, and 147 (99%) patients receiving combination therapy. The most common adverse events were diarrhoea, rash or erythema, hepatic adverse events, and neutropenia (not related to FEC administration), and were consistent with known safety profiles of lapatinib and trastuzumab. Three primary and eight secondary cardiac events occurred, with no significant difference in incidence between treatment groups for primary or any cardiac events. Interpretation Although event-free survival or overall survival did not differ between treatment groups, findings from our study confirm that patients who achieve pathological complete response after neoadjuvant anti-HER2 therapy have longer event-free and overall survival than do patients without pathological complete response. Funding GlaxoSmithKline.
Summary Background For patients with breast cancer and metastases in the sentinel nodes, axillary dissection has been standard treatment. However, for patients with limited sentinel-node involvement, ...axillary dissection might be overtreatment. We designed IBCSG trial 23–01 to determine whether no axillary dissection was non-inferior to axillary dissection in patients with one or more micrometastatic (≤2 mm) sentinel nodes and tumour of maximum 5 cm. Methods In this multicentre, randomised, non-inferiority, phase 3 trial, patients were eligible if they had clinically non-palpable axillary lymph node(s) and a primary tumour of 5 cm or less and who, after sentinel-node biopsy, had one or more micrometastatic (≤2 mm) sentinel lymph nodes with no extracapsular extension. Patients were randomly assigned (in a 1:1 ratio) to either undergo axillary dissection or not to undergo axillary dissection. Randomisation was stratified by centre and menopausal status. Treatment assignment was not masked. The primary endpoint was disease-free survival. Non-inferiority was defined as a hazard ratio (HR) of less than 1·25 for no axillary dissection versus axillary dissection. The analysis was by intention to treat. Per protocol, disease and survival information continues to be collected yearly. This trial is registered with ClinicalTrials.gov , NCT00072293. Findings Between April 1, 2001, and Feb 28, 2010, 465 patients were randomly assigned to axillary dissection and 469 to no axillary dissection. After the exclusion of three patients, 464 patients were in the axillary dissection group and 467 patients were in the no axillary dissection group. After a median follow-up of 5·0 (IQR 3·6–7·3) years, we recorded 69 disease-free survival events in the axillary dissection group and 55 events in the no axillary dissection group. Breast-cancer-related events were recorded in 48 patients in the axillary dissection group and 47 in the no axillary dissection group (ten local recurrences in the axillary dissection group and eight in the no axillary dissection group; three and nine contralateral breast cancers; one and five regional recurrences; and 34 and 25 distant relapses). Other non-breast cancer events were recorded in 21 patients in the axillary dissection group and eight in the no axillary dissection group (20 and six second non-breast malignancies; and one and two deaths not due to a cancer event). 5-year disease-free survival was 87·8% (95% CI 84·4–91·2) in the group without axillary dissection and 84·4% (80·7–88·1) in the group with axillary dissection (log-rank p=0·16; HR for no axillary dissection vs axillary dissection was 0·78, 95% CI 0·55–1·11, non-inferiority p=0·0042). Patients with reported long-term surgical events (grade 3–4) included one sensory neuropathy (grade 3), three lymphoedema (two grade 3 and one grade 4), and three motor neuropathy (grade 3), all in the group that underwent axillary dissection, and one grade 3 motor neuropathy in the group without axillary dissection. One serious adverse event was reported, a postoperative infection in the axilla in the group with axillary dissection. Interpretation Axillary dissection could be avoided in patients with early breast cancer and limited sentinel-node involvement, thus eliminating complications of axillary surgery with no adverse effect on survival. Funding None.
Summary 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).
Summary Background The combined efficacy analysis of the TEXT and SOFT trials showed a significant disease-free survival benefit with exemestane plus ovarian function suppression (OFS) compared with ...tamoxifen plus OFS. We present patient-reported outcomes from these trials. Methods Between Nov 7, 2003, and April 7, 2011, 4717 premenopausal women with hormone-receptor positive breast cancer were enrolled in TEXT or SOFT to receive unmasked adjuvant treatment with 5 years of exemestane plus OFS or tamoxifen plus OFS. Gonadotropin-releasing hormone analogue triptorelin, bilateral oophorectomy, or bilateral ovarian irradiation were used to achieve OFS. Chemotherapy use was optional. Randomisation with permuted blocks was done with the International Breast Cancer Study Group's internet-based system and was stratified by chemotherapy use and status of lymph nodes. Patients completed a quality of life (QoL) form comprising several global and symptom indicators at baseline, every 6 months for 24 months, and then every year during years 3 to 6. Differences in the change of QoL from baseline between the two treatments were tested at 6 months, 24 months, and 60 months with mixed-models for repeated measures for each trial with and without chemotherapy and overall. The analysis was by intention to treat. At the time of analysis, the median follow-up was 5·7 years (IQR 3·7–6·9); treatment and follow-up of patients continue. The trials are registered with ClinicalTrials.gov , as NCT00066703 (TEXT) and NCT00066690 (SOFT). Findings Patients on tamoxifen plus OFS were more affected by hot flushes and sweats over 5 years than were those on exemestane plus OFS, although these symptoms improved. Patients on exemestane plus OFS reported more vaginal dryness, greater loss of sexual interest, and difficulties becoming aroused than did patients on tamoxifen plus OFS; these differences persisted over time. An increase in bone or joint pain was more pronounced, particularly in the short term, in patients on exemestane plus OFS than patients on tamoxifen plus OFS. Changes in global QoL indicators from baseline were small and similar between treatments over the 5 years. Interpretation Overall, from a QoL perspective, there is no strong indication to favour either exemestane plus OFS or tamoxifen plus OFS. The distinct effects of the two treatments on the burden of endocrine symptoms need to be addressed with patients individually. Funding Pfizer, International Breast Cancer Study Group, and US National Cancer Institute.
Summary Background Postmenopausal women with hormone receptor-positive early breast cancer have persistent, long-term risk of breast-cancer recurrence and death. Therefore, trials assessing endocrine ...therapies for this patient population need extended follow-up. We present an update of efficacy outcomes in the Breast International Group (BIG) 1-98 study at 8·1 years median follow-up. Methods BIG 1-98 is a randomised, phase 3, double-blind trial of postmenopausal women with hormone receptor-positive early breast cancer that compares 5 years of tamoxifen or letrozole monotherapy, or sequential treatment with 2 years of one of these drugs followed by 3 years of the other. Randomisation was done with permuted blocks, and stratified according to the two-arm or four-arm randomisation option, participating institution, and chemotherapy use. Patients, investigators, data managers, and medical reviewers were masked. The primary efficacy endpoint was disease-free survival (events were invasive breast cancer relapse, second primaries contralateral breast and non-breast, or death without previous cancer event). Secondary endpoints were overall survival, distant recurrence-free interval (DRFI), and breast cancer-free interval (BCFI). The monotherapy comparison included patients randomly assigned to tamoxifen or letrozole for 5 years. In 2005, after a significant disease-free survival benefit was reported for letrozole as compared with tamoxifen, a protocol amendment facilitated the crossover to letrozole of patients who were still receiving tamoxifen alone; Cox models and Kaplan-Meier estimates with inverse probability of censoring weighting (IPCW) are used to account for selective crossover to letrozole of patients (n=619) in the tamoxifen arm. Comparison of sequential treatments to letrozole monotherapy included patients enrolled and randomly assigned to letrozole for 5 years, letrozole for 2 years followed by tamoxifen for 3 years, or tamoxifen for 2 years followed by letrozole for 3 years. Treatment has ended for all patients and detailed safety results for adverse events that occurred during the 5 years of treatment have been reported elsewhere. Follow-up is continuing for those enrolled in the four-arm option. BIG 1-98 is registered at clinicaltrials.gov NCT00004205. Findings 8010 patients were included in the trial, with a median follow-up of 8·1 years (range 0–12·4). 2459 were randomly assigned to monotherapy with tamoxifen for 5 years and 2463 to monotherapy with letrozole for 5 years. In the four-arm option of the trial, 1546 were randomly assigned to letrozole for 5 years, 1548 to tamoxifen for 5 years, 1540 to letrozole for 2 years followed by tamoxifen for 3 years, and 1548 to tamoxifen for 2 years followed by letrozole for 3 years. At a median follow-up of 8·7 years from randomisation (range 0–12·4), letrozole monotherapy was significantly better than tamoxifen, whether by IPCW or intention-to-treat analysis (IPCW disease-free survival HR 0·82 95% CI 0·74–0·92, overall survival HR 0·79 0·69–0·90, DRFI HR 0·79 0·68–0·92, BCFI HR 0·80 0·70–0·92; intention-to-treat disease-free survival HR 0·86 0·78–0·96, overall survival HR 0·87 0·77–0·999, DRFI HR 0·86 0·74–0·998, BCFI HR 0·86 0·76–0·98). At a median follow-up of 8·0 years from randomisation (range 0–11·2) for the comparison of the sequential groups with letrozole monotherapy, there were no statistically significant differences in any of the four endpoints for either sequence. 8-year intention-to-treat estimates (each with SE ≤1·1%) for letrozole monotherapy, letrozole followed by tamoxifen, and tamoxifen followed by letrozole were 78·6%, 77·8%, 77·3% for disease-free survival; 87·5%, 87·7%, 85·9% for overall survival; 89·9%, 88·7%, 88·1% for DRFI; and 86·1%, 85·3%, 84·3% for BCFI. Interpretation For postmenopausal women with endocrine-responsive early breast cancer, a reduction in breast cancer recurrence and mortality is obtained by letrozole monotherapy when compared with tamoxifen montherapy. Sequential treatments involving tamoxifen and letrozole do not improve outcome compared with letrozole monotherapy, but might be useful strategies when considering an individual patient's risk of recurrence and treatment tolerability. Funding Novartis, United States National Cancer Institute, International Breast Cancer Study Group.
Summary Background Treatment with adjuvant trastuzumab for 1 year improves disease-free survival and overall survival in patients with human epidermal growth factor receptor 2 (HER2)-positive early ...breast cancer. We aimed to assess disease-free survival and overall survival after a median follow-up of 4 years for patients enrolled on the Herceptin Adjuvant (HERA) trial. Methods The HERA trial is an international, multicentre, randomised, open-label, phase 3 trial comparing treatment with trastuzumab for 1 and 2 years with observation after standard neoadjuvant, adjuvant chemotherapy, or both in patients with HER2-positive early breast cancer. The primary endpoint was disease-free survival. After a positive first interim analysis at a median follow-up of 1 year for the comparison of treatment with trastuzumab for 1 year with observation, event-free patients in the observation group were allowed to cross over to receive trastuzumab. We report trial outcomes for the 1-year trastuzumab and observation groups at a median follow-up of 48·4 months (IQR 42·0–56·5) and assess the effect of the extensive crossover to trastuzumab. Our analysis was by intention-to-treat. The HERA trial is registered with the European Clinical Trials Database, number 2005-002385-11. Findings The HERA trial population comprised 1698 patients randomly assigned to the observation group and 1703 to the 1-year trastuzumab group. Intention-to-treat analysis of disease-free survival showed a significant benefit in favour of patients in the 1-year trastuzumab group (4-year disease-free survival 78·6%) compared with the observation group (4-year disease-free survival 72·2%; hazard ratio HR 0·76; 95% CI 0·66–0·87; p<0·0001). Intention-to-treat analysis of overall survival showed no significant difference in the risk of death (4-year overall survival 89·3% vs 87·7%, respectively; HR 0·85; 95% CI 0·70–1·04; p=0·11). Overall, 885 patients (52%) of the 1698 patients in the observation group crossed over to receive trastuzumab, and began treatment at median 22·8 months (range 4·5–52·7) from randomisation. In a non-randomised comparison, patients in the selective-crossover cohort had fewer disease-free survival events than patients remaining in the observation group (adjusted HR 0·68; 95% CI 0·51–0·90; p=0·0077). Higher incidences of grade 3–4 and fatal adverse events were noted on 1-year trastuzumab than in the observation group. The most common grade 3 or 4 adverse events, each in less than 1% of patients, were congestive cardiac failure, hypertension, arthralgia, back pain, central-line infection, hot flush, headache, and diarrhoea. Interpretation Treatment with adjuvant trastuzumab for 1 year after chemotherapy is associated with significant clinical benefit at 4-year median follow-up. The substantial selective crossover of patients in the observation group to trastuzumab was associated with improved outcomes for this cohort. Funding F Hoffmann-La Roche, Michelangelo Foundation.
Summary Background Trastuzumab has established efficacy against breast cancer with overexpression or amplification of the HER2 oncogene. The standard of care is 1 year of adjuvant trastuzumab, but ...the optimum duration of treatment is unknown. We compared 2 years of treatment with trastuzumab with 1 year of treatment, and updated the comparison of 1 year of trastuzumab versus observation at a median follow-up of 8 years, for patients enrolled in the HERceptin Adjuvant (HERA) trial. Methods The HERA trial is an international, multicentre, randomised, open-label, phase 3 trial comparing treatment with trastuzumab for 1 and 2 years with observation after standard neoadjuvant chemotherapy, adjuvant chemotherapy, or both in 5102 patients with HER2-positive early breast cancer. The primary endpoint was disease-free survival. The comparison of 2 years versus 1 year of trastuzumab treatment involved a landmark analysis of 3105 patients who were disease-free 12 months after randomisation to one of the trastuzumab groups, and was planned after observing at least 725 disease-free survival events. The updated intention-to-treat comparison of 1 year trastuzumab treatment versus observation alone in 3399 patients at a median follow-up of 8 years (range 0–10) is also reported. This study is registered with ClinicalTrials.gov , number NCT00045032. Findings We recorded 367 events of disease-free survival in 1552 patients in the 1 year group and 367 events in 1553 patients in the 2 year group (hazard ratio HR 0·99, 95% CI 0·85–1·14, p=0·86). Grade 3–4 adverse events and decreases in left ventricular ejection fraction during treatment were reported more frequently in the 2 year treatment group than in the 1 year group (342 20·4% vs 275 16·3% grade 3–4 adverse events, and 120 7·2% vs 69 4·1% decreases in left ventricular ejection fraction, respectively). HRs for a comparison of 1 year of trastuzumab treatment versus observation were 0·76 (95% CI 0·67–0·86, p<0·0001) for disease-free survival and 0·76 (0·65–0·88, p=0·0005) for overall survival, despite crossover of 884 (52%) patients from the observation group to trastuzumab therapy. Interpretation 2 years of adjuvant trastuzumab is not more effective than is 1 year of treatment for patients with HER2-positive early breast cancer. 1 year of treatment provides a significant disease-free and overall survival benefit compared with observation and remains the standard of care. Funding F Hoffmann-La Roche (Roche).
Summary Background The anti-HER2 monoclonal antibody trastuzumab and the tyrosine kinase inhibitor lapatinib have complementary mechanisms of action and synergistic antitumour activity in models of ...HER2-overexpressing breast cancer. We argue that the two anti-HER2 agents given together would be better than single-agent therapy. Methods In this parallel groups, randomised, open-label, phase 3 study undertaken between Jan 5, 2008, and May 27, 2010, women from 23 countries with HER2-positive primary breast cancer with tumours greater than 2 cm in diameter were randomly assigned to oral lapatinib (1500 mg), intravenous trastuzumab (loading dose 4 mg/m2 , subsequent doses 2 mg/kg), or lapatinib (1000 mg) plus trastuzumab. Treatment allocation was by stratified, permuted blocks randomisation, with four stratification factors. Anti-HER2 therapy alone was given for the first 6 weeks; weekly paclitaxel (80 mg/m2 ) was then added to the regimen for a further 12 weeks, before definitive surgery was undertaken. After surgery, patients received adjuvant chemotherapy followed by the same targeted therapy as in the neoadjuvant phase to 52 weeks. The primary endpoint was the rate of pathological complete response (pCR), analysed by intention to treat. This trial is registered with ClinicalTrials.gov , NCT00553358. Findings 154 patients received lapatinib, 149 trastuzumab, and 152 the combination. pCR rate was significantly higher in the group given lapatinib and trastuzumab (78 of 152 patients 51·3%; 95% CI 43·1–59·5) than in the group given trastuzumab alone (44 of 149 patients 29·5%; 22·4–37·5; difference 21·1%, 9·1–34·2, p=0·0001). We recorded no significant difference in pCR between the lapatinib (38 of 154 patients 24·7%, 18·1–32·3) and the trastuzumab (difference −4·8%, −17·6 to 8·2, p=0·34) groups. No major cardiac dysfunctions occurred. Frequency of grade 3 diarrhoea was higher with lapatinib (36 patients 23·4%) and lapatinib plus trastuzumab (32 21·1%) than with trastuzumab (three 2·0%). Similarly, grade 3 liver-enzyme alterations were more frequent with lapatinib (27 17·5%) and lapatinib plus trastuzumab (15 9·9%) than with trastuzumab (11 7·4%). Interpretation Dual inhibition of HER2 might be a valid approach to treatment of HER2-positive breast cancer in the neoadjuvant setting. Funding GlaxoSmithKline.
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