Randomized phase III trial of trastuzumab monotherapy followed by trastuzumab plus docetaxel versus trastuzumab plus docetaxel as first-line therapy in patients with HER2-positive metastatic breast cancer: the JO17360 Trial Group

We evaluated the efficacy and safety of sequential therapy with trastuzumab monotherapy (H-mono) followed by H plus docetaxel (D) after disease progression (H → H + D) versus combination therapy with H + D as first-line therapy. Patients with human epidermal growth factor receptor type 2 (HER2)-positive metastatic breast cancer (MBC) and left ventricular ejection fraction >50% were randomly assigned to either (a) H → H + D [H, once weekly 2 mg/kg (loading dose, 4 mg/kg); D, once every 3 weeks 60 mg/m²] or (b) H + D. Primary endpoints were progression-free survival (PFS) for the H-mono stage of the H → H + D group and H + D group and overall survival (OS) for both groups. Secondary endpoints were overall response rate, time to treatment failure, second PFS and safety. The planned number of patients was 160 patients in total. Of 112 patients enrolled, 107 were eligible. After 112 patients were enrolled, the Independent Data Monitoring Committee recommended stopping enrollment because PFS and OS were greater in the H + D group than the H → H + D group. Median PFS was 445 days in the H + D group versus 114 days for H-mono in the H → H + D group [hazard ratio (HR), 4.24; P < 0.01]. OS was significantly longer in the H + D group (HR, 2.72; P = 0.04). H + D therapy is significantly superior to H → H + D therapy as first-line therapy in patients with HER2-positive MBC, especially in terms of OS.     

Optimally tolerated dose of lapatinib in combination with docetaxel plus trastuzumab in first-line treatment of HER2-positive metastatic breast cancer

BackgroundThis phase IB, open-label, dose-escalation study evaluated the safety, tolerability, and optimally tolerated regimen (OTR) of lapatinib in combination with docetaxel and trastuzumab in patients with previously untreated stage IV metastatic breast cancer (MBC) tumors overexpressing human epidermal growth factor receptor 2 (HER2).Patients and methodsEvaluated dose regimens included lapatinib (500–1500 mg/day), docetaxel (triweekly; 60–100 mg/m²), and trastuzumab (weekly; 2 mg/kg fixed dose); prophylactic granulocyte colony-stimulating factor was included with regimens with ≥750 mg/day lapatinib. End points included OTR and safety/tolerability (primary), overall response rate (ORR), and pharmacokinetics (secondary).ResultsNone of the patients (N = 53) experienced dose-limiting toxic effects (DLTs) at the highest dose level; thus, the OTR of lapatinib with 100 mg/m² docetaxel was not determined. Common adverse events included diarrhea, nausea, alopecia, fatigue, and rash; grade 3/4 (≥2 patients) were neutropenia, diarrhea, leukopenia, peripheral neuropathy, and rash. Seven patients had DLTs (cycle 1). In 45 patients with measurable disease confirmed by bone scan, investigator-assessed ORR was 31%; without bone scan, confirmation was 64%; 8 patients without measurable disease were evaluated as stable. Lapatinib/docetaxel plasma concentrations were positively associated with complete response.ConclusionsLapatinib/docetaxel/trastuzumab is a feasible and well-tolerated treatment of untreated HER2-positive stage IV MBC. Two lapatinib/docetaxel OTR doses were recommended (1250 mg/75 mg/m²; 1000 mg/100 mg/m²).Clinical trial numberNCT00251433.     

Vinorelbine plus trastuzumab combination as first-line therapy for HER 2-positive metastatic breast cancer patients: an international phase II trial

The aim of this international phase II trial was to determine the efficacy and safety profile of weekly vinorelbine plus trastuzumab as first-line chemotherapy for women with HER 2-overexpressing metastatic breast cancer. Sixty-nine patients with tumours overexpressing HER 2 received vinorelbine: 30 mg m-2 week-1 and trastuzumab: 4 mg kg-1 on day 1 as a loading dose followed by 2 mg kg-1 week-1 starting on day 8. Sixty-two patients were evaluable for response and 69 patients were evaluable for toxicity. The overall response rate was 62.9%. The median time to response was 8.4 weeks, the median duration of response was 17.5 months, the median progression-free survival was 9.9 months (95% CI, 5.6-12.1) and the one-year progression-free survival was 39.1%. The median survival for all patients was 23.7 months (95% CI, 18.4-32.6). This regimen was safe: grade 3-4 neutropenia were observed over 17.7% of courses in 83.8% of patients, with only two episodes of febrile neutropenia (0.1%) in two patients (2.9%). Only one patient discontinued treatment due to grade 3 symptomatic cardiac dysfunction that resolved with therapy. Vinorelbine plus trastuzumab is one of the most active treatment regimens for patients with HER 2-positive metastatic breast cancer and demonstrates a very favourable safety profile allowing prolonged treatment with long-term survival. This study has been presented in part at the following conferences: The San Antonio Breast Cancer Symposium, San Antonio, TX, USA, 2003; The American Society of Clinical Oncology, Orlando, FL, USA, 2005.     

Pertuzumab in combination with trastuzumab and docetaxel for HER2-positive metastatic breast cancer

Overexpression of HER2 – found in approximately 15–20% of all breast cancers – is a negative prognostic factor. Although trastuzumab significantly improves the prognosis of HER2-positive breast cancer, half of the patients with metastatic breast cancer experience disease progression within 1 year. Pertuzumab is a novel HER2-targeted humanized monoclonal antibody that binds to the dimerization domain of HER2 and acts synergically with trastuzumab in inhibiting tumor progression. The CLEOPATRA trial demonstrated that adding pertuzumab to trastuzumab plus docetaxel significantly prolonged progression-free survival and overall survival without increasing severe adverse events. Conclusively, pertuzumab was approved by the US FDA in June 2012 for use in combination with trastuzumab and docetaxel for the treatment of patients with HER2-positive metastatic breast cancer. Furthermore, various clinical trials to evaluate the efficacy and safety of pertuzumab combined with other cytotoxic agents are ongoing at present. Thus, pertuzumab has been becoming important for the treatment of patients with HER2-positive metastatic breast cancer.     

A phase II study of ixabepilone and trastuzumab for metastatic HER2-positive breast cancer

BackgroundA multicenter NCI-sponsored phase II study was conducted to analyze the safety and efficacy of the combination of ixabepilone with trastuzumab in patients with metastatic HER2-positive breast cancer.Patients and methodsTwo cohorts were enrolled: cohort 1 had received no prior chemotherapy or trastuzumab for metastatic disease and cohort 2 had received 1–2 prior trastuzumab-containing regimens for metastatic disease. Patients in both cohorts received ixabepilone 40 mg/m² as a 3-h infusion and trastuzumab on day 1 of a 21-day cycle. Tumor biomarkers that may predict response to trastuzumab were explored.ResultsThirty-nine women entered the study with 15 patients in cohort 1 and 24 patients in cohort 2. Across both cohorts, the overall RR was 44%, with a clinical benefit rate (CR + PR + SD for at least 24 weeks) of 56%. Treatment-related toxic effects included neuropathy (grade ≥2, 56%), leukopenia (grade ≥2, 26%), myalgias (grade ≥2, 21%), neutropenia (grade ≥2, 23%), and anemia (grade ≥2, 18%).ConclusionsThis represents the first study of the combination of ixabepilone with trastuzumab for the treatment of metastatic HER2-positive breast cancer. These results suggest that the combination has encouraging activity as first and subsequent line therapy for metastatic breast cancer.     

Multicenter phase II study of trastuzumab in combination with epirubicin and docetaxel as first-line treatment for HER2-overexpressing metastatic breast cancer

Summary The primary objective of study is to evaluate cardiac safety of trastuzumab in combination with epirubicin and docetaxel. HER2-overexpressing metastatic breast cancer patients were enrolled in a two-stage, multicenter phase II trial with weekly trastuzumab (4 and then 2 mg/kg) with epirubicin and docetaxel (either 75 mg/m²) on day 1 every 3 weeks. After eight courses of chemotherapy, trastuzumab was continued as a single agent. To assess cardiotoxicity, patients were evaluated for left ventricular ejection fraction (LVEF) at baseline, every two cycles during chemotherapy and trastuzumab, and every 3 months during trastuzumab alone. Cardiotoxicity was defined as signs and/or symptoms of congestive heart failure (CHF) and/or an absolute decrease in LVEF of ≥20 units or a decline to ≤45%. In the first stage of the study, three episodes of cardiotoxicity were observed (two asymptomatic declines of LVEF and one CHF) in 29 patients, and recruitment continued. During follow-up of patients who continued trastuzumab after chemotherapy, seven further cardiologic events occurred (three asymptomatic decline of LVEF and four CHF). Therefore, recruitment was interrupted after the 45th patient. The majority of cardiac events occurred late during trastuzumab alone, half were asymptomatic and all cases of CHF were resolved using cardiac therapy. Complete and partial responses were 20 and 47%, respectively, and the median time to progression was 15.7 months (95% CI, 11.6–19.0 months). In light of the cardiotoxicity experienced during this study, we currently recommend that this combination be used only in controlled clinical trials under vigilant cardiac monitoring.     

A phase II study of weekly vinorelbine and trastuzumab in patients with HER2-positive metastatic breast cancer

BACKGROUND: Trastuzumab combined with cytotoxic agents presents encouraging results in metastatic breast cancer (MBC), but cardiac toxicity limits some combinations. The synergism shown with trastuzumab and the favorable tolerability profile of vinorelbine provided the rationale for investigating this combination. PATIENTS AND METHODS: Patients with HER2-positive MBC who had received <2 lines of chemotherapy for metastatic disease were included. Vinorelbine (25 mg/m2 on day 2, then weekly on day 1) and trastuzumab (4 mg/kg on day 1, then 2 mg/kg weekly) were administered for a maximum of 6 cycles (1 cycle=3 weeks). RESULTS: A total of 52 patients were enrolled. The median age was 50 years (range, 26-79 years). Ninety percent of the patients had received adjuvant chemotherapy, 42% received a first line of chemotherapy for MBC, and 69% had disease at visceral sites. The overall response rate was 58% (95% CI, 43%-71%). The median time to progression and overall survival were 7 months (95% CI, 5-9 months) and 26 months (95% CI, 20-32 months), respectively. Grade 4 neutropenia was present in 3 courses; neutropenic fever was not reported. The main grade 3 nonhematologic toxicities were asthenia, neuropathy, diarrhea, alopecia, and nausea/vomiting. No patients experienced serious cardiac toxicity. CONCLUSION: These results confirm that weekly vinorelbine/trastuzumab is an active and safe regimen in patients with HER2-positive MBC with an unfavorable prognosis.     

A phase II study of bevacizumab in combination with vinorelbine and trastuzumab in HER2-positive metastatic breast cancer

We aimed to evaluate the efficacy and feasibility of combining trastuzumab/vinorelbine with bevacizumab in patients with first-or second-line HER2-positive, metastatic breast cancer (MBC). Eligible patients had HER2-positive measureable MBC, with no more than one prior line of chemotherapy, and were treated with trastuzumab (4 mg/kg × 2 mg/kg weekly thereafter), vinorelbine (25 mg/m² weekly), and bevacizumab (10 mg/kg every 2 weeks). Co-primary endpoints were (a) the proportion of patients alive and progression-free at 1 year and (b) safety profile/feasibility. Feasibility was defined as a rate of grade 3/4 non-hematologic toxicity attributable to protocol-based therapy <20 %. Twenty-nine patients were enrolled (n = 22 first-line, n = 7 second-line). Median age was 48 years (range 37–68). The median number of cycles received was 8 (1–23) and median duration on treatment was 7.4 months (range 1–22). The study was closed early due to higher-than-expected rates of grade 3/4 non-hematologic toxicities, with 50 events in 20 patients. A total of six patients (21 %) were taken off study for treatment-related toxicity. Most common treatment-related toxicities included fatigue (n = 7), febrile neutropenia (n = 4), and headache (n = 3). At 1 year, 8/22 first-line (36 %) and 2/7 second-line (29 %) patients were alive and progression-free. Median PFS was 9.9 months and 7.8 months in the first- and second-line cohorts, respectively. Objective responses were observed in 16/22 (73 %) and 5/7 (71 %) patients in the first- and second-line settings. Although the combination of vinorelbine, trastuzumab, and bevacizumab showed notable activity in HER2-positive MBC, the proportion of first-line patients alive and progression-free at 1 year was deemed unlikely to reach the pre-defined threshold for declaring success. Additionally, unacceptable toxicity was observed, at rates greater than previously reported with vinorelbine/trastuzumab or vinorelbine/bevacizumab doublet combinations.     

A case of HER2-positive metastatic breast cancer responding to trastuzumab plus gemcitabine combination therapy

A 60-year-old woman was admitted to the hospital with left thigh pain. She had undergone mastectomy and axillary lymph node dissection for right breast cancer (T3N2M0) five years and two months earlier. The pathological diagnosis then was invasive ductal carcinoma with axillaryly mph node metastases. Hormone receptors and HER2 status were negative and positive (3+), respectively. The patient received adjuvant chemotherapy and radiotherapy, but bone metastases appeared 18 months after surgery. Although trastuzumab-combination chemotherapy with taxane and/or capecitabine was given, bone metastases in thoracic vertebra resulted in incomplete paralysis in both legs. She underwent thoraco-lumbar vertebral fixation 10 months before admission. A PET/CT revealed multiple bone metastases in the left femur as well as vertebrae, and CEA rose markedly. She received radiotherapy and trastuzumab monotherapy in addition to bisphosphonate. Temporarily, CEA decreased, but because recurrence nests were recognized in the supraclavicle and mediastinum after the eight-month treatment, trastuzumab monotherapy was followed by trastuzumab plus vinorelbine combined therapy. This regimen markedly reduced CEA after three months, but it rose again over the following three months. As S-1-combined therapy was not effective, trastuzumab+gemcitabine (1 g/week and two weeks on/one week off) combined therapy was started. CEA decreased markedly after 4 cycles, and FDG accumulation in the recurrence region was markedly improved. The adverse event during this treatment was minor, and PS was sufficiently maintained. These results suggest that trastuzumab plus gemcitabine combination therapy is effective for HER2-positive metastatic breast cancer.     

High efficacy of gemcitabine and cisplatin plus trastuzumab in patients with HER2-overexpressing metastatic breast cancer: a phase II study

AimsEffective and tolerable regimens are sought specifically in women who have been pre-treated with anthracyclines and taxanes. Gemcitabine and cisplatin plus trastuzumab has shown synergistic activity in vitro, and provides a new mechanism of drug interaction. This multicentre phase II study aimed to evaluate the efficacy and tolerability of gemcitabine and cisplatin plus trastuzumab in previously treated patients with metastatic breast cancer (MBC).Materials and methodsPreviously treated patients with human epidermal growth factor receptor 2 (HER2) overexpressing MBC were enrolled in a multicentre phase II study (DAKO Hercep Test 3+). Treatment consisted of gemcitabine (750 mg/m²), cisplatin (30 mg/m²) given on days 1 and 8 every 3 weeks, and trastuzumab (4 mg/kg loading dose, 2 mg/kg weekly).ResultsTwenty patients were recruited, all of whom had previously received chemotherapy (12 pre-treated with taxanes, 18 pre-treated with anthracyclines seven pre-treated with taxanes and trastuzumab). A median of six cycles of the study treatment was delivered. There were eight partial responses, for an overall response rate of 40% (95% confidence interval 16.5–63.5%). The clinical benefit rate (complete response plus partial response plus stable disease) was 80% (95% CI 54.2–95.8%). The response rate in patients who had already received a trastuzumab-based regimen for MBC was 57.1% (95% CI 7.7–100%). Median time to progression was 10.2 months, and median overall survival was 18.8 months. Main toxicities were leukopenia (grade 3 in 55% of patients) and thrombocytopenia (grade 3 in 35% and grade 4 in 5% of patients). Non-haematological toxicity was rarely severe.ConclusionsCombination chemotherapy with gemcitabine and cisplatin plus trastuzumab is well tolerated and active in patients with HER2 overexpressing MBC, even after prior exposure to anthracyclines and taxanes.     

Emerging approaches for treating HER2-positive metastatic breast cancer beyond trastuzumab

Because metastatic breast cancer (MBC) is incurable in most cases, the goals of treatment are improvement in quality of life, management of symptoms, and prolonged survival. The human epidermal growth factor receptor 2 (HER2) is overexpressed in up to 30% of breast tumors, and before the development of HER-targeted therapy, HER2 positivity was predictive of poorer clinical outcomes. Trastuzumab and pertuzumab (anti-HER2 monoclonal antibodies), lapatinib (a small molecule inhibitor of HER2 and the epidermal growth factor receptor [EGFR]) are approved for treating HER2-positive MBC in the United States. Although trastuzumab plus chemotherapy is currently regarded as the first-line standard of care for HER2-positive MBC, it is not without shortcomings; these include its association with certain adverse events (e.g. cardiotoxic effect) and development of resistance. A number of investigational agents that target HER2 and other members of that receptor family are in clinical development for patients with HER2-positive MBC whose disease has progressed on trastuzumab. In addition, in an effort to overcome treatment resistance, clinical trials are evaluating combination therapy (investigational HER-targeted agents with trastuzumab or lapatinib). This review discusses recently completed and ongoing phase II and III clinical trials of investigational HER-targeted agents in the setting of trastuzumab-progressive, HER2-positive MBC.     

SWOG S0215: a phase II study of docetaxel and vinorelbine plus filgrastim with weekly trastuzumab for HER2-positive,stage IV breast cancer

SWOG trial S0102 showed significant activity of the combination of docetaxel and vinorelbine in HER2-negative metastatic breast cancer (MBC). For HER2-positive patients, additional benefit may occur with the addition of trastuzumab due to its synergy with docetaxel and vinorelbine. Patients with HER2-positive MBC, but without prior chemotherapy for MBC or adjuvant taxane, were eligible. Docetaxel (60 mg/m²) was given intravenously on Day 1, vinorelbine (27.5 mg/m²) intravenously on Days 8 and 15, and filgrastim (5 μg/kg) on Days 2–21 of a 21-day cycle. In addition, patients received weekly infusions of trastuzumab (2 mg/kg) after an initial bolus of 4 mg/kg. The primary outcome was 1 year overall survival (OS), with secondary outcomes of progression-free survival (PFS), response rate, and toxicity. Due to slow accrual (February 2003–December 2006), enrollment was stopped after 76 of 90 planned patients. There have been 32 deaths and 51 progressions among the 74 eligible patients who received treatment. The estimated 1 year OS was 93% (95% CI 84–97%) with a median of 48 months. One-year PFS was 70% (95% CI 58–79%) with a median of 20 months. Response rate for measurable disease was 84%. No deaths were attributed to treatment. Grade 4 toxicities were reported for 19% with neutropenia the most common (15%). The most common grade 3 toxicities (33%) were leucopenia (14%) and fatigue (10%). The combination of trastuzumab, docetaxel, and vinorelbine is effective as first-line chemotherapy in HER2-positive MBC with minimal toxicity. One-year survival estimates are among the highest reported in this population.     

Efficacy and safety of trastuzumab plus capecitabine in heavily pretreated patients with HER2-positive metastatic breast cancer

Purpose We retrospectively evaluated the efficacy and safety of combination therapy of trastuzumab plus capecitabine in heavily pretreated patients with HER2-positive metastatic breast cancer (MBC). Methods Patients with HER2-positive MBC who had been administered the combination therapy between July 2003 and July 2006 at the Cancer Institute Hospital, Tokyo, were retrospectively reviewed. Capecitabine (828 mg/m²) was given twice daily for 3 weeks followed by a 1-week rest period; this was repeated every 4 weeks. Trastuzumab was given at 4 mg/kg as an initial loading dose intravenously, followed by 2 mg/kg weekly. We investigated objective response rate (ORR), clinical benefit rate (CBR), and time-to-treatment failure (TTF) according to the Response Evaluation Criteria in Solid Tumors guidelines. Adverse events were graded according to the National Cancer Institute, Common Toxicity Criteria, version 3.0. Results A total of 49 patients were assessed and median follow-up time of patients was 16.2 months (1.4–43.5 months). ORR was 16% (95% confidence interval: 7–30%) and CBR was 47% (95% confidence interval: 32–62%). Median TTF was 5.4 months. Common adverse effects were hand–foot syndrome, liver dysfunction, and bone marrow suppression. Grade 3 adverse events were observed in nine patients (18%). One patient (2%) suffered from symptomatic chronic heart failure, which improved after discontinuation of trastuzumab. Conclusions The combination therapy of trastuzumab plus capecitabine is effective and tolerable for heavily pretreated patients with HER2-positive MBC.     

The success story of trastuzumab emtansine,a targeted therapy in HER2-positive breast cancer

Trastuzumab emtansine is a unique antibody–drug conjugate targeting selectively human epidermal growth factor receptor 2 (HER2)-positive breast cancer cells, thus conferring high efficacy with minimal systemic toxicities. Trastuzumab emtansine consists of a monoclonal antibody trastuzumab and potent cytotoxic agent DM1, combined together through a stable thioether bond. First-in-man phase I study set the maximum tolerated dose at 3.6 mg/kg given intravenously on a 3-weekly regimen. In phase II studies, trastuzumab emtansine at 3.6 mg/kg provided objective tumour responses and clinical benefit with an encouraging safety profile. Over these studies, trastuzumab emtansine had favourable pharmacokinetics. No accumulation of trastuzumab emtansine or catabolites was observed even after repeated dosing and free DM1 was very low in circulation. The stability of trastuzumab emtansine in circulation justifies the minimal systemic toxicity observed. Recently, a randomised international open-label phase III study confirmed the efficacy and safety of trastuzumab emtansine versus lapatinib plus capecitabine in patients with HER2-positive locally advanced or metastatic breast cancer. Overall survival was significantly improved in the trastuzumab emtansine arm. Safety outcomes were also favourable. The adverse events traditionally related to chemotherapy were markedly lower or absent with trastuzumab emtansine. Cardiotoxicity, frequently observed in HER2-directed therapy, was not reported. Although thrombocytopenia and elevations in hepatic enzymes were reported with trastuzumab emtansine, these events were reversible and manageable. Ongoing trials investigating trastuzumab emtansine as a single-agent or in combination with other agents, will determine the place of trastuzumab emtansine in the current therapeutic strategies deployed for HER2-metastatic breast cancer.     

Epirubicin plus low-dose trastuzumab in HER2 positive metastatic breast cancer

Purpose This phase II study, evaluated the activity and cardiotoxicity of first-line epirubicin plus low-dose trastuzumab (LD-T) in patients with HER2 positive MBC. Methods Patients received epirubicin 90 mg/sqm every 3 weeks plus weekly LD-T (2 mg/kg loading dose, then 1 mg/kg). After 6/8 cycles of epirubicin, single agent trastuzumab was continued. Cardiotoxicity was defined as signs or symptoms of congestive heart failure (CHF), or ≥15% decline in LVEF without symptoms, or <15% LVEF decline to less than 50%, without symptoms. Results Forty-five patients were enrolled. Twenty-three received prior adjuvant anthracyclines. Overall response rate was 61.4%. The median time to progression was 7.4 months and the median survival was 32.8 months. Two (4.5%) patients developed CHF. Conclusions Epirubicin plus LD-T is an active regimen, however, the relatively high rate of cardiotoxicity together with the availability of less cardiotoxic and active trastuzumab-containing combinations precludes further evaluation of this regimen. An invited commentary to this article can be found at doi:.     

Biomarker results from the AVADO phase 3 trial of first-line bevacizumab plus docetaxel for HER2-negative metastatic breast cancer

Background:

Combining bevacizumab with first-line chemotherapy significantly improves progression-free survival (PFS) in HER2-negative metastatic breast cancer (mBC). However, identification of patients benefitting most from bevacizumab remains elusive. The AVADO trial included an extensive optional exploratory biomarker programme.

Methods:

Patients with HER2-negative mBC were randomised to receive docetaxel with placebo or bevacizumab. The primary end point was PFS. Plasma samples were analysed using a multiplex ELISA. Blood mRNA expression was assessed using quantitative PCR. Tumour tissue samples were analysed by immunohistochemistry. Single-nucleotide polymorphisms (SNPs) involved in the VEGF pathway were analysed in germline DNA.

Results:

Samples for biomarker analysis were available from 24–54% of the 736 treated patients (depending on specimen type). The most consistent potential predictive effect was observed with plasma VEGF-A and VEGFR-2; high baseline concentrations were associated with greater treatment effect. Blood mRNA analyses suggested a greater bevacizumab effect in patients with high VEGF₁₂₁. No consistent predictive effect was seen for tumour neuropilin or other candidate tumour markers by immunohistochemistry, or for any of the SNPs investigated.

Conclusion:

Plasma VEGF-A and VEGFR-2 are potential predictive markers for bevacizumab efficacy, supporting findings in gastric and pancreatic cancers. Plasma VEGF-A is being evaluated prospectively in mBC in the MERiDiAN trial.