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Purpose Trastuzumab and pertuzumab are human epidermal growth factor receptor 2 (HER2) -targeted monoclonal antibodies, and trastuzumab emtansine (T-DM1) is an antibody-drug conjugate that combines the properties of trastuzumab with the cytotoxic activity of DM1. T-DM1 demonstrated encouraging efficacy and safety in a phase II study of patients with previously untreated HER2-positive metastatic breast cancer. Combination T-DM1 and pertuzumab showed synergistic activity in cell culture models and had an acceptable safety profile in a phase Ib and II study. Methods In the MARIANNE study, 1,095 patients with centrally assessed, HER2-positive, advanced breast cancer and no prior therapy for advanced disease were randomly assigned 1:1:1 to control (trastuzumab plus taxane), T-DM1 plus placebo, hereafter T-DM1, or T-DM1 plus pertuzumab at standard doses. Primary end point was progression-free survival (PFS), as assessed by independent review. Results T-DM1 and T-DM1 plus pertuzumab showed noninferior PFS compared with trastuzumab plus taxane (median PFS: 13.7 months with trastuzumab plus taxane, 14.1 months with T-DM1, and 15.2 months with T-DM1 plus pertuzumab). Neither experimental arm showed PFS superiority to trastuzumab plus taxane. Response rate was 67.9% in patients who were treated with trastuzumab plus taxane, 59.7% with T-DM1, and 64.2% with T-DM1 plus pertuzumab; median response duration was 12.5 months, 20.7 months, and 21.2 months, respectively. The incidence of grade ≥ 3 adverse events was numerically higher in the control arm (54.1%) versus the T-DM1 arm (45.4%) and T-DM1 plus pertuzumab arm (46.2%). Numerically fewer patients discontinued treatment because of adverse events in the T-DM1 arms, and health-related quality of life was maintained for longer in the T-DM1 arms. Conclusion T-DM1 showed noninferior, but not superior, efficacy and better tolerability than did taxane plus trastuzumab for first-line treatment of HER2-positive, advanced breast cancer.

Purpose ASCO and the College of American Pathologists (ASCO-CAP) recently recommended further changes to the evaluation of human epidermal growth factor receptor 2 gene (HER2) amplification by fluorescent in situ hybridization (FISH). We retrospectively assessed the impact of these new guidelines by using annotated Breast Cancer International Research Group (BCIRG) -005, BCIRG-006, and BCIRG-007 clinical trials data for which we have detailed outcomes. Patients and Methods The HER2 FISH status of BCIRG-005/006/007 patients with breast cancers was re-evaluated according to current ASCO-CAP guidelines, which designates five different groups according to HER2 FISH ratio and average HER2 gene copy number per tumor cell: group 1 (in situ hybridization [ISH]-positive): HER2-to-chromosome 17 centromere ratio ≥ 2.0, average HER2 copies ≥ 4.0; group 2 (ISH-positive): ratio ≥ 2.0, copies < 4.0; group 3 (ISH-positive): ratio < 2.0, copies ≥ 6.0; group 4 (ISH-equivocal): ratio < 2.0, copies ≥ 4.0 and < 6.0; and group 5 (ISH-negative): ratio < 2.0, copies < 4.0. We assessed correlations with HER2 protein, clinical outcomes by disease-free survival (DFS) and overall survival (OS) and benefit from trastuzumab therapy (hazard ratio [HR]). Results Among 10,468 patients with breast cancers who were successfully screened for trial entry, 40.8% were in ASCO-CAP ISH group 1, 0.7% in group 2; 0.5% in group 3, 4.1% in group 4, and 53.9% in group 5. Distributions were similar in screened compared with accrued subpopulations. Among accrued patients, FISH group 1 breast cancers were strongly correlated with immunohistochemistry 3+ status (P < .0001), whereas groups 2, 3, 4, and 5 were not; however, groups 2, 4 and, 5 were strongly correlated with immunohistochemistry 0/1+ status (all P < .0001), whereas group 3 was not. Among patients accrued to BCIRG-005, group 4 was not associated with significantly worse DFS or OS compared with group 5. Among patients accrued to BCIRG-006, only group 1 showed a significant benefit from trastuzumab therapy (DFS HR, 0.71; 95% CI, 0.60 to 0.83; P < .0001; OS HR, 0.69; 95% CI, 0.55 to 0.85; P = .0006), whereas group 2 did not. Conclusion Our findings support the original categorizations of HER2 by FISH status in BCIRG/Translational Research in Oncology trials.

Purpose: Among postmenopausal women with endocrine-responsive breast cancer, the aromatase inhibitor letrozole, when compared with tamoxifen, has been shown to significantly improve disease-free survival (DFS) and time to distant recurrence (TDR). We investigated whether letrozole monotherapy prolonged overall survival (OS) compared with tamoxifen monotherapy., Patients and Methods: Of 8,010 postmenopausal women with hormone receptor-positive, early breast cancer enrolled on the Breast International Group (BIG) 1-98 study, 4,922 were randomly assigned to 5 years of continuous adjuvant therapy with either letrozole or tamoxifen. Of 2,459 patients enrolled in the tamoxifen treatment arm, 619 (25.2%) selectively crossed over to either adjuvant or extended letrozole after initial trial results were presented in January 2005. To gain better estimates of relative treatment effects in the presence of selective crossover, we used inverse probability of censoring weighted (IPCW) modeling., Results: Weighted Cox models, by using IPCW, estimated a statistically significant, 18% reduction in the hazard of an OS event with letrozole treatment (hazard ratio [HR], 0.82; 95% CI, 0.70 to 0.95). Estimates of 5-year OS on the basis of IPCW were 91.8% and 90.4% for letrozole and tamoxifen, respectively. The HRs of DFS and TDR events by using IPCW modeling were 0.83 (95% CI, 0.74 to 0.94) and 0.80 (95% CI, 0.67 to 0.94), respectively (P < .05 for DFS, OS, and TDR). Median follow-up was 74 months., Conclusion: Adjuvant treatment with letrozole, compared with tamoxifen, significantly reduces the risk of death, the risk of recurrent disease, and the risk of recurrence at distant sites in postmenopausal women with hormone receptor-positive breast cancer.

Purpose: Approximately 35% of HER2-amplified breast cancers have coamplification of the topoisomerase II-alpha (TOP2A) gene encoding an enzyme that is a major target of anthracyclines. This study was designed to evaluate whether TOP2A gene alterations may predict incremental responsiveness to anthracyclines in some breast cancers., Methods: A total of 4,943 breast cancers were analyzed for alterations in TOP2A and HER2. Primary tumor tissues from patients with metastatic breast cancer treated in a trial of chemotherapy plus/minus trastuzumab were studied for amplification/deletion of TOP2A and HER2 as a test set followed by evaluation of malignancies from two separate, large trials for changes in these same genes as a validation set. Association between these alterations and clinical outcomes was determined., Results: Test set cases containing HER2 amplification treated with doxorubicin and cyclophosphamide (AC) plus trastuzumab, demonstrated longer progression-free survival compared to those treated with AC alone (P = .0002). However, patients treated with AC alone whose tumors contain HER2/TOP2A coamplification experienced a similar improvement in survival (P = .004). Conversely, for patients treated with paclitaxel, HER2/TOP2A coamplification was not associated with improved outcomes. These observations were confirmed in a larger validation set, where HER2/TOP2A coamplification was again associated with longer survival when only anthracycline-containing chemotherapy was used for treatment compared with outcome in HER2-positive cancers lacking TOP2A coamplification., Conclusion: In a study involving nearly 5,000 breast malignancies, both test set and validation set demonstrate that TOP2A coamplification, not HER2 amplification, is the clinically useful predictive marker of an incremental response to anthracycline-based chemotherapy. Absence of HER2/TOP2A coamplification may indicate a more restricted efficacy advantage for breast cancers than previously thought.

Purpose: Docetaxel-trastuzumab (TH) is effective therapy for HER2-amplified metastatic breast cancer (MBC). Preclinical findings of synergy between docetaxel, carboplatin, and trastuzumab (TCH) prompted a phase III randomized trial comparing TCH with TH in patients with HER2-amplified MBC., Patients and Methods: Two hundred sixty-three patients were randomly assigned to receive eight 3-week cycles of TH (trastuzumab plus docetaxel 100 mg/m(2)) or TCH (trastuzumab plus carboplatin at area under the serum concentration-time curve 6 and docetaxel 75 mg/m(2)). Trastuzumab was given at 4 mg/kg loading dose followed by a 2 mg/kg dose once per week during chemotherapy, and then 6 mg/kg once every 3 weeks until progression., Results: Patient characteristics were balanced between groups. There was no significant difference between TH and TCH in terms of the primary end point, time to progression (medians of 11.1 and 10.4 months, respectively; hazard ratio, 0.914; 95% CI, 0.694 to 1.203; P = .57), response rate (72% for both groups), or overall survival (medians of 37.1 and 37.4 months, respectively; P = .99). Rates of grades 3 or 4 adverse effects for TH and TCH, respectively, were neutropenic-related complications, 29% and 23%; thrombocytopenia, 2% and 15%; anemia, 5% and 11%; sensory neuropathy, 3% and 0.8%; fatigue, 5% and 12%; peripheral edema, 3.8% and 1.5%; and diarrhea, 2% and 10%. Two patients given TCH died of sepsis, and one patient given TH experienced sudden cardiac death. Absolute left ventricular ejection fraction decline > 15% was seen in 5.5% of patients on the TH arm and 6.7% of patients on the TCH arm., Conclusion: Adding carboplatin did not enhance TH antitumor activity.TH (docetaxel, 100 mg/m(2)) and TCH (docetaxel, 75 mg/m(2)) demonstrated efficacy with acceptable toxicity in women with HER2-amplified MBC.

Purpose: Previous analyses of the Breast International Group (BIG) 1-98 four-arm study compared initial therapy with letrozole or tamoxifen including patients randomly assigned to sequential treatment whose information was censored at the time of therapy change. Because this presentation may unduly reflect early events, the present analysis is limited to patients randomly assigned to the continuous therapy arms and includes protocol-defined updated results., Patients and Methods: Four thousand nine hundred twenty-two of the 8,028 postmenopausal women with receptor-positive early breast cancer randomly assigned (double-blind) to the BIG 1-98 trial were assigned to 5 years of continuous adjuvant therapy with either letrozole or tamoxifen; the remainder of women were assigned to receive the agents in sequence. Disease-free survival (DFS) was the primary end point., Results: At a median follow-up time of 51 months, we observed 352 DFS events among 2,463 women receiving letrozole and 418 events among 2,459 women receiving tamoxifen. This reflected an 18% reduction in the risk of an event (hazard ratio, 0.82; 95% CI, 0.71 to 0.95; P = .007). No predefined subsets showed differential benefit. Adverse events were similar to previous reports. Patients on tamoxifen experienced more thromboembolic events, endometrial pathology, hot flashes, night sweats, and vaginal bleeding. Patients on letrozole experienced more bone fractures, arthralgia, low-grade hypercholesterolemia, and cardiovascular events other than ischemia and cardiac failure., Conclusion: The present updated analysis, which was limited to patients on monotherapy arms in BIG 1-98, yields results similar to those from the previous primary analysis but more directly comparable with results from other trials of continuous therapy using a single endocrine agent.

Purpose: To evaluate the effect on survival and quality of life of maintaining hemoglobin (Hb) in the range of 12 to 14 g/dL with epoetin alfa versus placebo in women with metastatic breast cancer (MBC) receiving first-line chemotherapy., Patients and Methods: Eligible patients were randomly assigned to receive epoetin alfa 40,000 U once weekly or placebo for 12 months. Study drug was initiated if baseline Hb was < or = 13 g/dL or when Hb decreased to < or = 13g/dL during the study. The primary end point was 12-month overall survival (OS)., Results: The study drug administration was stopped early in accordance with a recommendation from the Independent Data Monitoring Committee because of higher mortality in the group treated with epoetin alfa. Enrollment had been completed, with 939 patients enrolled (epoetin alfa, n = 469; placebo, n = 470). Most patients had Hb more than 12 g/dL at baseline (median Hb, 12.8 g/dL) or during the study. From the final analysis, 12-month OS was 70% for epoetin alfa recipients and 76% for placebo recipients (P = .01). Optimal tumor response and time to disease progression were similar between groups. The reason for the difference in mortality between groups could not be determined from additional subsequent analyses involving both study data and chart review., Conclusion: In this trial, the use of epoetin alfa to maintain high Hb targets in women with MBC, most of whom did not have anemia at the start of treatment, was associated with decreased survival. Additional research is required to clarify the potential impact of erythropoietic agents on survival when the Hb target range is 10 to 12 g/dL.

Purpose: N,N-diethyl-2-[4-(phenylmethyl)phenoxy]ethanamine (DPPE; tesmilifene) is a novel agent that augments chemotherapy cytotoxicity in vitro and in vivo. A phase II trial combining DPPE and doxorubicin (DOX) in metastatic breast carcinoma showed increased response over that expected with DOX. We report a phase III trial comparing DOX with DPPE plus DOX in metastatic or recurrent breast cancer., Patients and Methods: Anthracycline-naive women with measurable metastatic disease were randomly assigned to receive, every 21 days, either DOX 60 mg/m(2) intravenously or DOX during the last 20 minutes of an 80-minute infusion of DPPE (5.3 mg/kg), in both cases to cumulative DOX doses of 450 mg/m(2). Patients receiving DPPE were aggressively premedicated to ameliorate toxicity. End points included progression-free survival (PFS), response rate (RR), and response duration (RD), quality of life (QOL), toxicity, and overall survival (OS)., Results: A planned interim analysis failed to detect an RR difference more than 5%. The study was closed to additional accrual and all DPPE was discontinued. The final analysis was conducted as planned after 256 progression events (median follow-up, 20.5 months). There was no significant difference in RR, RD, or PFS between arms. DPPE plus DOX was statistically superior to DOX in OS (hazard ratio, 0.66; 95% CI, 0.48 to 0.91; P =.021). DPPE plus DOX was associated with more gastrointestinal and CNS toxicity. No consistent influence on QOL was detected., Conclusion: This study demonstrated no advantage in RR, RD, or PFS but significantly superior OS for DPPE plus DOX. Additional studies of DPPE are warranted.

Purpose: This randomized, multicenter, phase III study compared doxorubicin and docetaxel (AT) with doxorubicin and cyclophosphamide (AC) as first-line chemotherapy (CT) in metastatic breast cancer (MBC)., Patients and Methods: Patients (n = 429) were randomly assigned to receive doxorubicin 50 mg/m(2) plus docetaxel 75 mg/m(2) (n = 214) or doxorubicin 60 mg/m(2) plus cyclophosphamide 600 mg/m(2) (n = 215) on day 1, every 3 weeks for up to eight cycles., Results: Time to progression (TTP; primary end point) and time to treatment failure (TTF) were significantly longer with AT than AC (median TTP, 37.3 v 31.9 weeks; log-rank P =.014; median TTF, 25.6 v 23.7 weeks; log-rank P =.048). The overall response rate (ORR) was significantly greater for patients taking AT (59%, with 10% complete response [CR], 49% partial response [PR]) than for those taking AC (47%, with 7% CR, 39% PR) (P =.009). The ORR was also higher with AT in patients with visceral involvement (58% v 41%; liver, 62% v 42%; lung, 58% v 35%), three or more organs involved (59% v 40%), or prior adjuvant CT (53% v 41%). Overall survival (OS) was comparable in both arms. Grade 3/4 neutropenia was frequent in both groups, although febrile neutropenia and infections were more frequent for patients taking AT (respectively, 33% v 10%, P <.001; 8% v 2%, P =.01). Severe nonhematologic toxicity was infrequent in both groups, including grade 3/4 cardiac events (AT, 3%; AC, 4%)., Conclusion: AT significantly improves TTP and ORR compared with AC in patients with MBC, but there is no difference in OS. AT represents a valid option for the treatment of MBC.