Doxorubicin and paclitaxel versus fluorouracil, doxorubicin, and cyclophosphamide as first-line therapy for women with metastatic breast cancer: final results of a randomized phase III multicenter trial.

PURPOSE: This phase III trial compared the efficacy and safety of doxorubicin and paclitaxel (AT) to 5-fluorouracil, doxorubicin, and cyclophosphamide (FAC) as first-line therapy for women with metastatic breast cancer. PATIENTS AND METHODS: A total of 267 women with metastatic breast cancer were randomized to receive either AT (doxorubicin 50 mg/m(2) followed 24 hours later by paclitaxel 220 mg/m(2)) or FAC (5-fluorouracil 500 mg/m(2), doxorubicin 50 mg/m(2), cyclophosphamide 500 mg/m(2)), each administered every 3 weeks for up to eight cycles. Patients had to have measurable disease and an Eastern Cooperative Oncology Group performance status of 0 to 2. Only one prior non-anthracycline, nontaxane-containing adjuvant chemotherapy regimen was allowed. RESULTS: Overall response rates for patients randomized to AT and FAC were 68% and 55%, respectively (P =.032). Median time to progression and overall survival were significantly longer for AT compared with FAC (time to progression 8.3 months v 6.2 months [P =.034]; overall survival 23.3 months v 18.3 months [P =.013]). Therapy was generally well-tolerated (median of eight cycles delivered in each arm). Grade 3 or 4 neutropenia was more common with AT than with FAC (89% v 65%; P <.001); however, the incidence of fever and infection was low. Grade 3 or 4 arthralgia and myalgia, peripheral neuropathy, and diarrhea were more common with AT, whereas nausea and vomiting were more common with FAC. The incidence of cardiotoxicity was low in both arms. CONCLUSION: AT conferred a significant advantage in response rate, time to progression, and overall survival compared with FAC. Treatment was well-tolerated with no unexpected toxicities.     

Multicentric phase II trial of gemcitabine plus epirubicin plus paclitaxel as first-line chemotherapy in metastatic breast cancer

In this phase II, multicentre trial, patients with metastatic breast cancer (MBC) were treated with a combination of gemcitabine, epirubicin and paclitaxel (GET). The primary objective of this study was to determine the tolerability and activity in terms of complete responce (CR) and overall response rate of the GET combination in this patient population. Patients with no prior treatment for MBC, and at least one bidimensionally measurable lesion received gemcitabine 1000 mg m(-2) intravenously (i.v.) over 30 min on days 1 and 4, followed by epirubicin i.v. at 90 mg m(-2) on day 1, and paclitaxel 175 mg m(-2) over 3 h on day 1, every 21 days, up to eight courses. From May 1999 to June 2000, 48 patients were enrolled from seven Italian institutions. A total of 297 chemotherapy courses were administered with a median of six cycles patient(-1) (range 1-8). Seven patients (15%) obtained CR and 27 patients (56%) had partial responce, for an overall response rate of 71% (95% CI: 58.3-83.7). After a median follow-up of 23.7 months (range 7.0-34.4), median progression-free survival was 10.5 months (95% CI: 9.2-11.7), and median overall survival 25.9 months. The main haematological toxicity consisted of grade 3 or 4 neutropenia that occurred in 62% of cycles (22% grade 4 and 40% grade 3). The GET combination is active and well tolerated as first-line chemotherapy for MBC.     

Paclitaxel and epirubicin versus paclitaxel and carboplatin as first-line chemotherapy in patients with advanced breast cancer: a phase III study conducted by the Hellenic Cooperative Oncology Group.

BACKGROUND: To compare survival between patients with advanced breast cancer (ABC) treated with epirubicin/paclitaxel (Taxol) or paclitaxel/carboplatin (Cp) chemotherapy. PATIENTS AND METHODS: From January 1999 to April 2002, 327 eligible patients with ABC were randomized to receive either paclitaxel 175 mg/m(2) in a 3-h infusion followed by epirubicin (EPI) 80 mg/m(2) (group A) or paclitaxel, as in group A, followed by Cp at an AUC of 6 mg x min/ml (group B) every 3 weeks for six cycles. RESULTS: After a median follow-up of 23.5 months, median survival was not significantly different between the two groups (22.4 months versus 27.8 months, P=0.25), whereas median time to treatment failure was significantly longer in patients treated with paclitaxel/Cp (8.1 months in group A versus 10.8 months in group B, P=0.04). Both regimens were well tolerated. In total, 39 patients (24%) in group A and 46 (29%) in group B suffered at least one severe side-effect. Quality-of-life assessment and cost analysis did not reveal any significant differences between the two groups. CONCLUSION: Our study suggests that the paclitaxel/Cp combination is an effective therapeutic alternative for patients with ABC in which anthracycline administration has the potential of being harmful.     

Dose-dense sequential chemotherapy with epirubicin and paclitaxel versus the combination, as first-line chemotherapy, in advanced breast cancer: a randomized study conducted by the Hellenic Cooperative Oncology Group.

PURPOSE: To compare the efficacy of two different schedules of epirubicin and paclitaxel, as first-line chemotherapy, in patients with advanced breast cancer (ABC). PATIENTS AND METHODS: From October 1997 until May 1999, 183 eligible patients with ABC entered the study. Chemotherapy in group A (93 patients) consisted of four cycles of epirubicin at a dose of 110 mg/m(2) followed by four cycles of paclitaxel at a dose of 225 mg/m(2) in a 3-hour infusion. All cycles were repeated every 2 weeks with granulocyte colony-stimulating factor support. The therapeutic regimen in group B (90 patients) consisted of epirubicin (80 mg/m(2)) immediately followed by paclitaxel (175 mg/m(2) in a 3-hour infusion) every 3 weeks for six cycles. RESULTS: In total, 79 patients (85%) in group A and 72 patients (80%) in group B completed treatment. The median relative dose-intensity of epirubicin was 0.96 in both groups, and that of paclitaxel was 0.96 and 0.97 in groups A and B, respectively. The complete response rate was higher in group A (21.5% v 9% P =.02). Nevertheless, there was no significant difference in the overall response rate between the two groups (55% v 42%, P =.10). Severe neutropenia was more frequently observed with concurrent treatment. After a median follow-up of 16.5 months, median time to progression was 10 months in group A and 8.5 months in group B (P =.27), and median survival was 21.5 and 20 months, respectively (P =.17). CONCLUSION: The present study failed to demonstrate a significant difference in overall response rate between dose-dense sequential administration of epirubicin and paclitaxel compared with the combination of the two drugs given on the same day, even though the sequential treatment resulted in a significantly higher complete response rate.     

Vinorelbine,epirubicin and fluorouracil as first-line therapy in metastatic breast cancer--a phase II trial

A phase II study was conducted to assess the toxicity and response rate of vinorelbine (NavelbineR) combined with epirubicin and fluorouracil (NEF) in metastatic breast cancer. Vinorelbine was delivered at a dose of 25 mg/m 2 on days 1 and 8, epirubicin at 60 mg/m 2 on day 1 and fluorouracil at 600 mg/m 2 on day 1, at 3-week intervals. Forty consecutive ambulant patients with breast cancer with measurable metastases were treated with a total of 310 cycles (median 8) as first-line therapy. The objective response rate was 83% (95% CI 71-95) (6/40 CR 15%, 27/40 PR 68%). In 3 patients, CNS metastases were detected during NEF therapy those who had a partial response in their visceral metastases. Median time to progression was 13 months (95% CI 7-19) and estimated median survival time was 32 months. The main dose-limiting adverse effect, grade III-IV haematological toxicity, was reported in 92% of patients. One patient died of neutropenic sepsis. Grade III infections requiring hospitalization were observed in 8 patients (20%). Half of the patients complained of mild constipation, nausea or stomatitis, which were easily managed. Almost all patients had grade III alopecia. One patient with previous adjuvant anthracycline therapy (CEF ×9 two years earlier) developed fatal grade IV cardiac failure associated with pulmonary emboli 2 months after completion of NEF therapy (PR with 6 cycles). In line with the observations of others conducting phase II first-line trials combining vinorelbine and epirubicin, it is concluded that the NEF regimen is effective in metastatic breast cancer. Haematological toxicity, however, requires dose reductions in many patients. Furthermore, careful monitoring of cardiac function is necessary, particularly in patients who received prior adjuvant anthracycline therapy.     

Capecitabine plus paclitaxel versus epirubicin plus paclitaxel as first-line treatment for metastatic breast cancer: efficacy and safety results of a randomized, phase III trial by the AGO Breast Cancer Study Group

Capecitabine/taxane combinations are highly active in metastatic breast cancer (MBC). We conducted a randomized, phase III, noninferiority trial comparing capecitabine plus paclitaxel (XP) with epirubicin plus paclitaxel (EP) as first-line therapy for MBC, regarding progression-free survival (PFS) as primary efficacy endpoint. Females who had received no prior chemotherapy for MBC were randomized to six 3-weekly cycles of XP (capecitabine 1000 mg/m² b.i.d., days 1–14; paclitaxel 175 mg/m² 3-h infusion, day 1) or EP (epirubicin 60 mg/m² 1-h infusion, day 1; paclitaxel as above). Secondary endpoints included response rate, overall survival, tolerability, and quality of life (QoL). Each arm included 170 patients, most of whom received all six cycles as planned. The difference in means of (logarithmic) PFS times (?0.205) did not meet the pre-defined level for noninferiority (?0.186). However, PFS was similar in the two arms [HR: XP vs. EP: 1.012 (95 % CI 0.785–1.304); median 10.4 months XP vs. 9.2 months EP]. Overall survival was also similar [HR 1.027 (95 % CI 0.740–1.424); median 22.0 vs. 26.1 months], and response rate was 47 % versus 42 %. Both regimens were tolerable: there were more grade 3/4 diarrhea and grade 3 hand–foot syndromes with XP and more grade 3/4 hematologic toxicities with EP. There were no major differences in QoL. Although, noninferiority of XP to EP was formally not proven, first-line XP was active and feasible. XP is a valid first-line alternative to anthracycline/taxane regimens, especially in patients previously treated with adjuvant anthracyclines.     

Docetaxel and doxorubicin compared with doxorubicin and cyclophosphamide as first-line chemotherapy for metastatic breast cancer: results of a randomized, multicenter, phase III trial.

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.     

Phase III trial of cyclophosphamide, epirubicin, fluorouracil (CEF) versus cyclophosphamide, mitoxantrone, fluorouracil (CNF) in women with metastatic breast cancer

Background: The mitoxantrone combination CNF and the epirubicin combination CEF have shown similar activity and less toxicity than the standard CAF combination in metastatic breast cancer (MBC). A prospective randomised study was started to compare safety and activity between CEF and CNF administered using a classical chemotherapeutic schedule in MBC.Patients and methods: From December 1987 to June 1993, 151 patients were randomised to receive cyclophosphamide (C) 100mgm^–2 p.o. days 1–14, fluorouracil (F) 500mgm^–2 i.v. days 1 and 8, and epirubicin (E) 30mgm^–2 i.v. days 1 and 8, or mitoxantrone (N) 6 mgm^–2 i.v. days 1 and 8, every 4 weeks. Seventythree patients were eligible for CEF and 72 for CNF.Results: Objective responses were observed in 61.6 of the CEF group and 44.4 in CNF group (p=0.004). The median duration of response was 64 weeks in CEF and 50 weeks in CNF group (p=0.02) and median time to progression was 51 and 33 weeks, respectively (p=0.0004). At the time of analysis, all except six patients (one in CNF and five in CEF) had died and the median survival time in the CEF group was longer than in CNF (74.4 weeks vs 51.4 weeks; log-rank ² test p=0.015). CNF produced more hematologic toxicity than CEF (WHO scale; grades 2–4): leucopenia 84% vs 68% (p=0.03) and trombocytopenia 17% vs 4.5% (p=0.01); CEF caused more grade 2 and 3 alopecia: 93% vs 70% (p=0.00 1).Conclusion: The combination CEF using this schedule and dosage in metastatic breast cancer is more effective with less toxicity than CNF, except for alopecia, and was associated with longer survival.     

Weekly first-line chemotherapy of metastatic breast cancer with cyclophosphamide and epirubicin.

Forty-six patients with metastatic breast cancer who had not received previous chemotherapy for advanced disease entered a phase II trial of weekly chemotherapy with cyclophosphamide (250 mg/m2) + epirubicin (25 mg/m2) for 16 weeks. The overall response rate was 61% (95% confidence limits, 47-75%), with 10 complete and 17 partial responses. Toxicity was mild and confined to nausea and vomiting and asymptomatic neutropenia (except in 2 cases). Sixty-three per cent of patients had no side effects. Weekly cyclophosphamide + epirubicin is an active and nontoxic regimen for patients with metastatic breast cancer who have had no prior anthracycline-containing adjuvant chemotherapy.     

Epirubicin and cyclophosphamide versus epirubicin and docetaxel as first-line therapy for women with metastatic breast cancer: final results of a randomised phase III trial

BackgroundThis randomised phase III trial was carried out to compare the efficacy and safety of epirubicin and cyclophosphamide (EC) with epirubicin and docetaxel (Taxotere) (ED) as first-line chemotherapy for metastatic breast cancer.Patients and methodsPatients (n = 240) were randomly assigned to receive either ED (epirubicin 75 mg/m² and docetaxel 75 mg/m²) or EC (epirubicin 90 mg/m² and cyclophosphamide 600 mg/m²). The primary end point was objective response rate (ORR). Secondary end points were progression-free survival (PFS), overall survival (OS), and safety.ResultsORR for patients randomly assigned to receive EC and ED were 42% and 47%, respectively (P = 0.63). Median PFS [10.1 versus 10.3 months; hazard ratio (HR) 0.98; log-rank P = 0.38] and OS (19.9 versus 30.0 months; HR 0.663; log-rank P = 0.21) were comparable in both arms. Although grade 3/4 leucopenia occurred more frequently with ED (81% versus 73%; P = 0.01), there were no significant differences in the incidence of febrile neutropenia and grade 3/4 infections. Grade 3/4 non-haematologic toxicity was infrequent in both arms. Congestive heart failure was observed in one patient in each arm.ConclusionIn this randomised trial, no differences in the efficacy study end points were observed between the two treatment arms.     

Phase III trial of liposomal doxorubicin and cyclophosphamide compared with epirubicin and cyclophosphamide as first-line therapy for metastatic breast cancer.

OBJECTIVE: To ascertain the efficacy and tolerability of non-pegylated liposomal doxorubicin (Myocet) and epirubicin combined with cyclophosphamide in the first-line treatment of patients with metastatic breast cancer. METHODS: One hundred and sixty anthracycline-na?ve metastatic breast cancer patients were randomised to receive Myocet (M; 75 mg/m(2)) or epirubicin (E; 75 mg/m(2)) in combination with cyclophosphamide (C; 600 mg/m(2)), every 3 weeks for up to eight cycles. OUTCOME MEASURES: Response (overall response = complete + partial response rates), time to disease progression, overall survival and cardiac function (left ventricular ejection fraction). RESULTS: Overall response rates were 46% and 39% for MC and EC treatment, respectively (P=0.42). MC was superior to EC with respect to median time to treatment failure (5.7 versus 4.4 months; P=0.01) and median time to disease progression (7.7 versus 5.6 months; P=0.02). Median survival times were 18.3 and 16.0 months for MC and EC, respectively (P=0.504). Unsurprisingly, given an equimolar comparison, neutropenia and stomatitis/mucositis were significantly more common in patients who received MC. However, there was less injection site toxicity with MC. Both treatments showed a low incidence of cardiotoxicity. CONCLUSION: Myocet appears to be an acceptable alternative to epirubicin as a first-line treatment for patients with metastatic breast cancer because it combines the dose-effect reliability of doxorubicin with the level of safety provided by epirubicin.     

A prospective randomized trial of fluorouracil versus fluorouracil plus cisplatin in the treatment of metastatic colorectal cancer: a Hoosier Oncology Group trial

From May 1984 through December 1986, 141 patients with metastatic adenocarcinoma of the colon or rectum were entered on this Hoosier Oncology Group (HOG) trial evaluating the role of cisplatin in systemic therapy. Patients were stratified by the presence or absence of hepatic metastases and by performance status, and were subsequently randomized to receive fluorouracil (5-FU) (15 mg/kg/wk) alone or the same dose of 5-FU plus cisplatin (60 mg/m2 every 3 weeks). The total duration of treatment was six cycles (18 weeks). In 132 fully evaluable patients the objective response rates were 19% for 5-FU and 22% for 5-FU plus cisplatin. Statistically, the median survival times of 40 and 39 weeks were not significantly different (P = .62). However, the median duration of remission (MDR) was superior (P = .05) for 5-FU alone. This study fails to confirm clinically significant synergy of 5-FU plus cisplatin in the treatment of metastatic colorectal cancer.     

Multicenter randomized phase III trial of epirubicin plus paclitaxel vs epirubicin followed by paclitaxel in metastatic breast cancer patients: focus on cardiac safety

The aim of the study was to evaluate cardiac safety of two different schedules of Epirubicin and Paclitaxel in advanced breast cancer patients enrolled into a multicenter randomized phase III trial. Patients received Epirubicin 90 mg m(-2) plus Paclitaxel 200 mg m(-2) (3-h infusion) on day 1 every 3 weeks for eight courses (arm A), or Epirubicin 120 mg m(-2) on day 1 every 3 weeks for four courses followed by four courses of Paclitaxel 250 mg m(-2) on day 1 every 3 weeks (arm B). Left ventricular ejection fraction was evaluated by bidimesional echocardiography at baseline, after four and eight courses of chemotherapy and every 4 months during follow-up. Baseline median left ventricular ejection fraction was 60% in arm A and 65% in arm B; after four courses, figures were 57 and 60%, respectively. After eight courses, the median left ventricular ejection fraction in arm A declined to 50% while no further reduction was detected in arm B by adding four courses of high-dose Paclitaxel. Seven episodes of congestive heart failure were observed during treatment in arm A. Present monitoring demonstrated that the risk of congestive heart failure or impairment in the cardiac function correlated only with the cumulative dose of Epirubicin; no impact on cardiotoxicity can be attributed to high-dose Paclitaxel.     

Combination chemotherapy with cyclophosphamide, fluorouracil, and either epirubicin or mitoxantrone: a comparative randomized multicenter study in metastatic breast carcinoma

From February 1987 to January 1989, 60 patients with advanced breast cancer and no prior chemotherapy for advanced disease were randomized and studied, with 31 treated with fluorouracil, epirubicin, and cyclophosphamide (FEC) and 29 patients with fluorouracil, mitoxantrone, and cyclophosphamide (FNC). Doses were 500 mg/m2 fluorouracil, 500 mg/m2 cyclophosphamide, and 50 mg/m2 epirubicin2 or 10 mg/m mitoxantrone, i.v. Day 1 every 3 weeks. There were no statistically significant differences in pretreatment patient characteristics between the groups. Fifty-six patients were evaluable for response (29 in the FEC arm and 27 in the FNC arm). The response rates were 48.2% for the FEC group (complete response (CR) 10.3% and partial response (PR) 37.9%) and 40.7% for the FNC group (CR 3.7% and PR 37%) (not significantly different, NS). The median response duration was 247 and 267 days, respectively (NS), the median time to progression and time to treatment failure was 244 and 155.5 days for the FEC group and 86 and 98 days for the FNC group, respectively (NS). The incidence of nausea/vomiting was 87.1% in the FEC group and 79.3% in the FNC group, with comparable severity. Alopecia occurred in 80.6% of FEC patients and 44.8% of FNC patients (p less than 0.05). The incidences and degrees of severity of leukopenia, anemia, and cardiotoxicity were comparable in the two treatment groups. Efficacy and toxicity of the two regimens were quite similar. FNC can improve the quality of life of patients by providing significantly less alopecia.     

Final results of a randomized phase III trial comparing cyclophosphamide, epirubicin, and fluorouracil with a dose-intensified epirubicin and cyclophosphamide + filgrastim as neoadjuvant treatment in locally advanced breast cancer: an EORTC-NCIC-SAKK multicenter study.

PURPOSE: To compare the efficacy of a standard anthracycline-based regimen to a dose-intensified anthracycline regimen in locally advanced breast cancer. PATIENTS AND METHODS: Locally advanced breast cancer patients were randomly assigned onto a study comparing cyclophosphamide (C; 75 mg/m(2) orally days 1 to 14), epirubicin (E; 60 mg/m(2) intravenously [IV] days 1, 8), and fluorouracil (F; 500 mg/m(2) IV days 1, 8) six cycles every 28 days versus E (120 mg/m(2) IV day 1), C (830 mg/m(2) IV day 1), and granulocyte colony-stimulating factor (filgrastim; 5 micro g/kg/d subcutaneously days 2 to 13) six cycles every 14 days. The study was designed to detect a 15% improvement; that is, from 50% to 65% in median progression-free survival (PFS) in favor of the dose-intensified regimen. RESULTS: A total of 448 patients were enrolled over a period of 3 years. The median dose intensity delivered for C and E reached, respectively, 85% and 87% of that planned in the CEF arm and 96% and 95% of that planned in the EC arm. The dose-intensified arm was slightly more emetogenic and generated more grade 3 to 4 anemia but less febrile neutropenia episodes. After a median follow-up of 5.5 years, 277 events have been reported. The median PFS was 34 and 33.7 months for CEF and EC, respectively (P =.68), and the 5-year survival rate was 53% and 51% for CEF and EC, respectively (P =.94). CONCLUSION: Dose-intensified EC does not provide a measurable therapeutic benefit over CEF as neoadjuvant chemotherapy for unselected locally advanced breast cancer patients.     

Randomized phase III trial of marimastat versus placebo in patients with metastatic breast cancer who have responding or stable disease after first-line chemotherapy: Eastern Cooperative Oncology Group trial E2196.

PURPOSE: To determine whether a matrix metalloproteinase inhibitor improves progression-free survival (PFS) in patients with metastatic breast cancer who have responding or stable disease after first-line chemotherapy. PATIENTS AND METHODS: One hundred seventy-nine eligible patients were randomly assigned to receive oral marimastat (10 mg bid; n = 114) or a placebo (n = 65) within 3 to 6 weeks of completing six to eight cycles of first-line doxorubicin- and/or taxane-containing chemotherapy for metastatic disease. Patients were evaluated every 3 months until disease progression. RESULTS: When comparing placebo with marimastat, there was no significant difference in PFS (median, 3.1 months v 4.7 months, respectively; hazard ratio, 1.26; 95% CI, 0.91 to 1.74; P = .16) or overall survival (median, 26.6 months v 24.7 months, respectively; hazard ratio, 1.03; 95% CI, 0.73 to 1.46; P = .86). Patients treated with marimastat were more likely to develop grade 2 or 3 musculoskeletal toxicity (MST), a known complication of the drug indicative of achieving a biologic effect, compared with patients administered placebo (63% v 22%, respectively; P < .0001). Patients with grade 2 or 3 MST had significantly inferior survival compared with patients who had grade 0 or 1 MST (median, 22.5 months v 28.2 months; P = .04). In addition, patients who had a marimastat plasma concentration of at least 10 ng/mL at month 1 and/or 3 were significantly more likely to have grade 2 to 3 MST (P < .0001). CONCLUSION: Marimastat does not prolong PFS when used after first-line chemotherapy for metastatic breast cancer. Patients with higher marimastat levels exhibited MST, and MST was associated with inferior survival.