Phase I study of the safety and pharmacokinetics of trabectedin with docetaxel in patients with advanced malignancies

PURPOSE

Combination therapy with trabectedin and docetaxel was evaluated in patients with advanced malignancies.

METHODS

In this open-label phase 1 study, docetaxel (60 or 75 mg/m(2); 1-h intravenous infusion) was given on day 1 of a 21-day cycle in combination with escalating doses of trabectedin (0.4-1.3 mg/m(2) by 3-h intravenous infusion, 1 h after docetaxel) and prophylactic granulocyte colony-stimulating factor (G-CSF). Maximum tolerated dose (MTD) as primary objective and safety, plasma pharmacokinetics, and antitumor activity as secondary objectives were assessed.

RESULTS

Patients (N = 49) received a median of four cycles of treatment. MTD was 1.3 mg/m(2) trabectedin and 60 mg/m(2) docetaxel for patients with limited and 1.1 mg/m(2) trabectedin and 60 mg/m(2) docetaxel for patients with unlimited prior chemotherapy. Dose-limiting toxicities (during cycle 1) included elevated alanine aminotransferase (ALT) and fatigue in patients with limited prior chemotherapy and elevated ALT and febrile neutropenia in those with unlimited prior chemotherapy. The most common drug-related adverse events were nausea (65 %), fatigue (63 %), and neutropenia (53 %). One patient achieved a complete response. Thirty patients had stable disease, and 11 had stable disease for ≥6 months. Pharmacokinetic results for trabectedin plus docetaxel were similar to those previously reported for the single agents.

CONCLUSION

In patients with previously treated, advanced malignancies, the combination of therapeutic doses of trabectedin and docetaxel showed clinical activity and was tolerable with prophylactic G-CSF, with no evidence of clinically important drug interactions.

Activity of trabectedin in germline BRCA1/2-mutated metastatic breast cancer: results of an international first-in-class phase II study

BACKGROUND

Breast cancer is a heterogeneous disease defined by both germline and somatic abnormalities. In preclinical models, tumors carrying homologous recombination defects are highly sensitive to trabectedin. This phase II trial evaluated the efficacy and safety of trabectedin in BRCA1/2 germline mutation carriers with pretreated metastatic breast cancer (MBC).

PATIENTS AND METHODS

Trabectedin 1.3 mg/m(2) as a 3-h i.v. infusion was administered every 3 weeks until progression or intolerance. The primary efficacy end point was the objective response rate (ORR) as per RECIST. Secondary efficacy end points comprised time-to-event end points, and changes in tumor volume and expression of tumor marker CA15.3. Safety was evaluated using the NCI-CTCAE.

RESULTS

Forty BRCA1/2 germline mutation carriers with MBC were included. Confirmed partial response (PR) occurred in 6 of 35 assessable patients [ORR = 17%; 95% confidence interval (CI) 7% to 34%] and lasted 1.4-6.8 months. Median PFS was 3.9 months (95% CI 1.6-5.5 months). Eight patients (21%) showed changes in tumor volume, and 14 (40%) a clinical benefit. Trabectedin-related adverse events were generally mild/moderate, the most common being fatigue, nausea, constipation and anorexia. Severe laboratory abnormalities (neutropenia, transaminase increases) were mostly transient and noncumulative, and were managed by dose adjustments.

CONCLUSIONS

With the caveat of the limited patient number, trabectedin monotherapy showed activity and was well tolerated in heavily pretreated MBC patients selected for germline BRCA mutation. These results prompt further evaluation of trabectedin alone or combined with other specific drugs in this indication.

CLINICALTRIALSGOV

NCT00580112.

Triple-negative breast cancer: are we making headway at least?

The so-called triple-negative breast cancer, as defined by tumors that lack estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 (HER2) overexpression, has generated growing interest in recent years despite representing less than 20% of all breast cancers. These tumors constitute an important clinical challenge, as they do not respond to endocrine treatment and other targeted therapies. As a group they harbor an aggressive clinical phenotype with early development of visceral metastases and a poor long-term prognosis. While chemotherapy remains effective in triple-negative disease, research continues to further identify potential new targets based on phenotypical and molecular characteristics of these tumors. In this respect, the presence of a higher expression of different biomarkers including epidermal growth factor receptor, vascular endothelial growth factor receptor, fibroblast growth factor receptor and Akt activation has led to a proliferation of clinical trials assessing the role of inhibitors to these pathways in triple-negative tumors. Moreover, the described overlap between triple-negative and basal-like tumors, and the similarities with tumors arising in the BRCA1 mutation carriers has offered potential therapeutic avenues for patients with these cancers including poly (ADP-ribose) polymerase inhibitors and a focus on a higher sensitivity to alkylating chemotherapy agents. Results from these trials have shown some benefit in small subgroups of patients, even in single-agent therapy, which reflects the heterogeneity of triple-negative breast cancer and highlights the need for a further subclassification of these types of tumors for better prognosis identification and treatment individualization.

Multicenter phase II study of trabectedin in patients with metastatic castration-resistant prostate cancer

BACKGROUND

This multicenter phase II trial evaluated the efficacy and safety of trabectedin in metastatic castration-resistant prostate cancer (CRPC).

PATIENTS AND METHODS

Two schedules were evaluated in three cohorts: weekly as 3-h i.v. infusion at 0.58 mg/m(2) for 3 out of 4 weeks (Cohort A, n = 33), and every 3 weeks (q3wk) as 24-h infusion at 1.5 mg/m(2) (Cohort B1, n = 5) and 1.2 mg/m(2) (Cohort B2, n = 20). The primary end point was prostate-specific antigen (PSA) response; secondary end points included safety, tolerability and time to progression (TTP).

RESULTS

Trabectedin resulted in PSA declines ≥ 50% in 12.5% (Cohort A) and 10.5% (Cohort B2) of patients. Among men pretreated with taxane-based chemotherapy, PSA response was 13.6% (Cohort A) and 15.4% (Cohort B2). PSA responses lasted 4.1-8.6 months, and median TTP was 1.5 months (Cohort A) and 1.9 months (Cohort B2). The dose of 1.5 mg/m(2) (approved for soft tissue sarcoma) given as 24-h infusion q3wk was not tolerable in these patients. At 1.2 mg/m(2) q3wk and 0.58 mg/m(2) weekly, the most common adverse events were nausea, fatigue and transient neutropenia and transaminase increase.

CONCLUSIONS

Two different trabectedin schedules showed modest activity in metastatic CRPC. Further studies may require identification of predictive factors of response in prostate cancer.

Trabectedin in patients with advanced non-small-cell lung cancer (NSCLC) with XPG and/or ERCC1 overexpression and BRCA1 underexpression and pretreated with platinum

BACKGROUND

Previous studies in sarcoma found that a composite gene signature, including high expression of nucleotide excision repair (NER) genes (XPG and/or ERCC1) and low expression of homologous recombination repair (HR) genes (BRCA1), identifies a highly sensitive population of patients with significantly improved outcome to trabectedin. This exploratory phase II trial evaluated a customized trabectedin treatment according to this gene signature in patients with non-small cell lung cancer (NSCLC) after the failure of standard platinum-based treatment.

METHODS

Patients were selected according to their mRNA expression (elevated XPG and/or ERCC1, with low BRCA1) using the following values as cutoff: XPG=0.99, ERCC1=3.47 and BRCA1=12.00. Trabectedin was administered as a 1.3mg/m(2) 3-hour intravenous infusion every 3 weeks (q3wk). The primary efficacy endpoint was the progression-free survival rate at 3 months. Objective response according to the Response Evaluation Criteria in Solid Tumors (RECIST) was a secondary efficacy endpoint.

RESULTS

Two of 18 evaluable patients (11.1%; 95% CI, 1.38-34.7%) achieved progression-free survival rate at 3 months. The primary efficacy objective (at least 3 of 18 patients being progression-free at 3 months) was not met, and therefore the trial was early finalized. No objective responses per RECIST were achieved. Four patients had stable disease. Median PFS was 1.3 months, and median overall survival was 5.9 months. Trabectedin was usually well tolerated, with a safety profile similar to that described in patients with other tumor types.

CONCLUSIONS

Customized treatment with trabectedin 1.3mg/m(2) 3-h q3wk according to composite gene signature (XPG and/or ERCC1 overexpression, and BRCA1 underexpression) was well tolerated, but had modest activity in NSCLC patients pretreated with platinum. Therefore, further clinical trials with trabectedin as single agent in this indication are not warranted.

Effect of trabectedin on the QT interval in patients with advanced solid tumor malignancies

PURPOSE

The primary objective of this study was to access the potential effects of trabectedin on the QT/QTc interval in patients with locally advanced or metastatic solid tumors.

METHODS

Patients (n = 75) who had received ≤3 previous lines of chemotherapy and had either relapsed or had progressive disease were enrolled. Patients were administered 3-h intravenous infusions of placebo (saline) on day 1 and trabectedin (1.3 mg/m(2)) on day 2. Time-matched serial triplicate ECG recordings and pharmacokinetic blood samples were collected over 24 h on both days. Heart rate corrected mean QT intervals and changes from predose baseline in QTc (ΔQTc) were assessed. The difference in ΔQTc between trabectedin and placebo was calculated at each time point (ΔΔQTc).

RESULTS

The upper limits of the 90% confidence interval for ΔΔQTcF and ΔΔQTcB at all time points were less than the prespecified noninferiority margin of 10 ms (≤6.65 ms). No patient had a QTc > 500 ms or a time-matched increase from baseline in QTc > 60 ms at any time point. Regression analyses indicated ΔΔQTc was poorly correlated with trabectedin concentration. No adverse events suggestive of proarrhythmic potential were reported.

CONCLUSION

Trabectedin did not prolong the QTc interval. Safety and pharmacokinetic profiles of trabectedin were similar to that observed in other ovarian and breast cancer studies.

Trabectedin has a low cardiac risk profile: a comprehensive cardiac safety analysis

PURPOSE

This analysis provides a cross-study evaluation of the cardiac safety of trabectedin.

METHODS

Drug-related cardiac adverse events (CAEs) were retrieved from phase I-III clinical trials, pharmacovigilance databases, and spontaneously reported cases. Left ventricular ejection fraction (LVEF) was monitored in combination phase I studies with doxorubicin or pegylated liposomal doxorubicin (PLD) and in a phase III trial (with PLD).

RESULTS

CAEs [grade 4 cardiac arrest with severe pancytopenia and sepsis (n = 1 patient), grade 4 atrial fibrillation (n = 2), and grade 1 tachycardia (n = 1)] occurred in 4/283 patients (1.4%) in 6 single-agent phase I trials. CAEs (grade 1 sinus tachycardia in a hypertensive patient and grade 1 ventricular dysfunction) occurred in 2/155 patients (1.3%) in 4 phase I combination trials. Results from 19 single-agent phase II trials showed CAEs in 20/1,132 patients (1.8%): arrhythmias (tachycardia/palpitations; n = 13; 1.1%) were the most common. A rather similar rate of symptomatic CAEs was observed in both arms of a phase III trial in recurrent ovarian cancer: 6/330 patients (1.8%; PLD) and 11/333 patients (3.3%; trabectedin/PLD). No clinically relevant LVEF changes occurred in phase I combination trials. In the phase III trial, LVEF decreases from baseline were similar: 9% of patients (PLD) and 7% (trabectedin/PLD), with no relevant symptoms. During postmarketing experience in soft tissue sarcoma (2,046 patients treated), 4 CAEs (2 cardiac arrest, 2 cardiac failure; ~0.2%) occurred in patients with preexisting conditions.

CONCLUSIONS

Trabectedin has a low incidence of CAEs, consisting mainly of arrhythmias. This extensive data review indicates a low cardiac risk profile for trabectedin.

Phase I combination study of trabectedin and doxorubicin in patients with soft-tissue sarcoma

PURPOSE

To determine the dose of trabectedin plus doxorubicin with granulocyte colony-stimulating factor support associated with manageable neutropenia and acceptable dose-limiting toxicities (DLT) in patients with recurrent or persistent soft-tissue sarcoma.

METHODS

In this phase I, open-label, multicenter trial, patients previously treated with 0-1 prior chemotherapy regimens excluding doxorubicin, an Eastern Cooperative Oncology Group performance status 0-1, and adequate organ function received a 10- to 15-min i.v. infusion of doxorubicin 60 mg/m(2) immediately followed by a 3-h i.v. infusion of trabectedin 0.9 to 1.3 mg/m(2) on day 1 of a 3-week cycle. Because four of the first six patients experienced DLT-defining neutropenia during cycle 1, all subsequent patients received primary prophylactic granulocyte colony-stimulating factor. The maximum tolerated dose was the highest dose level with six or more patients in which less than one-third of the patients experienced severe neutropenia or DLT. Blood was collected during cycle 1 for pharmacokinetic analyses. Adverse events, tumor response, and survival were assessed.

RESULTS

Patients (N = 41) received a median of six cycles of treatment (range, 2-13). The maximum tolerated dose was trabectedin 1.1 mg/m(2) and doxorubicin 60 mg/m(2). Common grade 3/4 treatment-emergent adverse events were neutropenia (71%), alanine aminotransferase increase (46%), and thrombocytopenia (37%). Overall, 5 (12%) patients achieved a partial response and 34 (83%) maintained stable disease. Median progression-free survival was 9.2 months. Doxorubicin and trabectedin pharmacokinetics were not altered substantially with concomitant administration.

CONCLUSION

The combination of doxorubicin 60 mg/m(2) followed by trabectedin 1.1 mg/m(2) every 21 days is safe and active in patients with soft-tissue sarcoma.

Phase I trial of weekly trabectedin (ET-743) and gemcitabine in patients with advanced solid tumors

PURPOSE

To determine the maximum tolerated dose (MTD) of trabectedin plus gemcitabine administered on a weekly schedule in patients with advanced solid tumors.

METHODS

Patients with ECOG performance status 0-1 and adequate organ function were enrolled. On days 1, 8, and 15 of a 28-day cycle, patients received gemcitabine (starting dose, 800 mg/m(2)) followed by trabectedin (starting dose, 0.3 mg/m(2)). Strict liver function test treatment criteria were employed to avoid hepatic toxicity seen in previous trabectedin studies. Plasma samples were collected during cycles 1 and 2 for pharmacokinetic analyses.

RESULTS

Fifteen patients received >or=1 dose, with a median of two treatment cycles (range 1-10). The most common drug-related toxicity was hepatic. Dose reductions were required for trabectedin in four (27%) patients and gemcitabine in six (40%) patients. Cycle delays/dose holds were required in 11 (73%) patients and doses above trabectedin 0.4 mg/m(2) and gemcitabine 1,000 mg/m(2), which is the recommended phase II dose, were not feasible. Seven patients maintained stable disease after two cycles. Gemcitabine and trabectedin pharmacokinetics were not altered substantially with concomitant administration.

CONCLUSIONS

Given the lack of pharmacokinetic interaction and potential efficacy of trabectedin and gemcitabine combination therapy, further study is warranted with alternate schedules.

Definitive Chemoradiation for the Treatment of Locally Advanced Non–Small-Cell Lung Cancer

A third of patients with newly diagnosed non–small-cell lung cancer (NSCLC) have locally advanced disease not amenable for curative resection. Addition of chemotherapy to thoracic radiation improves survival in patients with locally advanced NSCLC when compared with thoracic radiation alone. Over the past two decades, we have made slow but steady progress in improving the outcomes of therapy in this subset of patients. This review summarizes the past two decades of research and outlines the direction we need to pursue to significantly enhance the outcomes. The widespread use of positron emission tomography (identifying those with occult distant metastatic disease and sparing them combined-modality therapy), improved radiation techniques, and better supportive care resulting in improved chemotherapy delivery have resulted in improved outcomes. There is considerable interest in studying the role of higher doses of thoracic radiation (74 Gy) in this disease, and this is the subject of an ongoing intergroup study. Despite some recent setbacks, molecularly targeted therapies need to be studied carefully in combination with chemoradiotherapy. There is an urgent need to develop regimens that incorporate chemotherapy agents that can be administered at doses that are systemically active and yet tolerable.

Trabectedin (ET-743): evaluation of its use in advanced soft-tissue sarcoma

Trabectedin (ET-743; Yondelis®) is a novel DNA-binding agent, originally derived from the marine tunicate, Ecteinascidia turbinata, and now produced synthetically. The efficacy of trabectedin in patients with advanced soft-tissue sarcoma has been demonstrated in three Phase II studies involving 189 previously treated patients. A pooled analysis of data from these studies showed that trabectedin induced tumor control (objective responses plus disease stabilization) in approximately 50% of patients; median overall survival was 10.3 months and progression-free survival at 6 months was 19.8%, with 29.3% of patients alive at 2 years. Responses were achieved in patients who were resistant to both doxorubicin and ifosfamide. Trabectedin is generally well tolerated, with adverse events being noncumulative, reversible and manageable. Unlike other commonly used cytotoxic agents, trabectedin is not associated with cardiotoxicity or neurotoxicity and alopecia is rare. Trabectedin is an interesting new anticancer agent that offers much promise for the treatment of advanced soft-tissue sarcoma.

The role of radiotherapy in lung cancer: Where is the evidence?

Radiotherapy is one of the main treatment modalities in lung cancer, contributing to both its cure and palliation. Thoracic irradiation has traditionally been considered the mainstay of treatment in inoperable stage III non-small cell lung cancer. However, despite technical developments and the addition of chemotherapy, the curative potential of radiotherapy in this subset of patients is disappointingly poor. The role of radiotherapy as an adjunct to pulmonary resection (preoperative and postoperative) is questionable, but well-designed and executed phase III studies are lacking. An important application of radiotherapy is palliation of tumor-related symptoms in the chest and in metastatic sites, such as bones and brain. In small cell lung cancer, routine applications of radiotherapy include chest radiotherapy in limited disease and prophylactic cranial irradiation in complete responders to chemotherapy, each increasing survival by about 5%.

Induction chemotherapy followed by chemoradiotherapy compared with chemoradiotherapy alone for regionally advanced unresectable stage III Non-small-cell lung cancer: Cancer and Leukemia Group B

PURPOSE

Standard therapy for unresectable stage III non-small-cell lung cancer includes concomitant chemoradiotherapy. In Cancer and Leukemia Group B 39801, we evaluated whether induction chemotherapy before concurrent chemoradiotherapy would result in improved survival.

PATIENTS AND METHODS

Between July 1998 and May 2002, 366 patients were randomly assigned to arm A, which involved immediate concurrent chemoradiotherapy with carboplatin area under the concentration-time curve (AUC) of 2 and paclitaxel 50 mg/m2 given weekly during 66 Gy of chest radiotherapy, or arm B, which involved two cycles of carboplatin AUC 6 and paclitaxel 200 mg/m2 administered every 21 days followed by identical chemoradiotherapy. The accrual goal was 360 patients.

RESULTS

Thirty-four percent of patients were female, 66% were male, and the median age was 63 years. Grade 3 or 4 toxicities during induction chemotherapy on arm B consisted mainly of neutropenia (18% and 20%, respectively). During concurrent chemoradiotherapy, there was no difference in severity of in-field toxicities of esophagitis (grade 3 and 4 were, respectively, 30% and 2% for arm A v 28% and 8% for arm B) and dyspnea (grade 3 and 4 were, respectively, 11% and 3% for arm A v 15% and 4% for arm B). Survival differences were not statistically significant (P = .3), with a median survival on arm A of 12 months (95% CI, 10 to 16 months) versus 14 months (95% CI, 11 to 16 months) on arm B and a 2-year survival of 29% (95% CI, 22% to 35%) and 31% (95% CI, 25% to 38%). Age, weight loss before therapy, and performance status were statistically significant predictive factors.

CONCLUSION

The addition of induction chemotherapy to concurrent chemoradiotherapy added toxicity and provided no survival benefit over concurrent chemoradiotherapy alone. The median survival achieved in each of the treatment groups is low, and the routine use of weekly carboplatin and paclitaxel with simultaneous radiotherapy should be re-examined.

Randomized phase II trial of docetaxel/irinotecan and gemcitabine/irinotecan with or without celecoxib in the second-line treatment of non-small-cell lung cancer

PURPOSE

Trials combining irinotecan/docetaxel and irinotecan/gemcitabine in second-line treatment of non-small-cell lung cancer (NSCLC) have yielded promising results. Preliminary data suggested that the selective cyclooxygenase -2 inhibitor celecoxib (CBX) might enhance efficacy of chemotherapeutic regimens. This multicenter, phase II, randomized trial investigated efficacy and safety of irinotecan and docetaxel and irinotecan and gemcitabine, with or without CBX, in second-line treatment of NSCLC.

PATIENTS AND METHODS

Patients 18 years or older were randomly assigned to receive irinotecan 60 mg/m2 and docetaxel 35 mg/m2, or irinotecan 100 mg/m2 and gemcitabine 1,000 mg/m2, with or without CBX 400 mg twice daily, for four cycles. Primary efficacy end points were median and 1-year survival probabilities. Patient-reported symptoms were assessed by the Lung Cancer Symptoms Scale (LCSS).

RESULTS

A total of 133 patients were assessable for efficacy and safety. Median survival time was 6.31 months for patients treated with CBX and 8.99 months for those treated with chemotherapy alone. One-year survival rates were 24% and 36% respectively. The overall toxicity rates and LCSS scores were similar between patients treated or not treated with CBX. Four deaths were considered possibly treatment related.

CONCLUSION

Survival results for the second-line regimens in this study were similar to results reported for single-agent therapy in this setting. CBX did not appear to enhance efficacy or improve patient-reported symptoms. The addition of high-dose CBX to second-line chemotherapy in NSCLC cannot be recommended.

Simultaneous Chemoradiotherapy Compared With Radiotherapy Alone After Induction Chemotherapy in Inoperable Stage IIIA or IIIB Non–Small-Cell Lung Cancer: Study CTRT99/97 by the Bronchial Carcinoma Therapy Group

Purpose

The aim of this study was to examine whether, after preceding induction chemotherapy, simultaneous chemoradiotherapy is superior to radiotherapy alone.

Patients and Methods

Patients with non–small-cell lung cancer in inoperable stage IIIA or IIIB received induction chemotherapy with two cycles of paclitaxel 200 mg/m2 and carboplatin area under the curve 6 every 3 weeks. Patients without progression at restaging after induction chemotherapy were randomly assigned to radiotherapy (60 Gy) or chemoradiotherapy (paclitaxel 60 mg/m2 weekly). The primary end point was overall survival; secondary end points were time to progression, response, and toxicity.

Results

Three hundred three patients entered the study, and 276 completed induction chemotherapy. Two hundred fourteen patients were randomly assigned (radiotherapy alone: n = 113; simultaneous chemoradiotherapy: n = 101). Median follow-up time of all randomly assigned patients was 13.6 months (interquartile range [IQR], 6.4 to 29.0 months), and median follow-up time of the subgroup of censored patients (n = 52) was 37.4 months (IQR, 5.9 to 57.0 months; maximum, 76.1 months). Toxicities during the induction phase were mild. During radiotherapy, overall toxicity rates were not significantly different between the two arms. Median survival times in the radiotherapy group and chemoradiotherapy group were 14.1 months (95% CI, 11.8 to 16.3 months) and 18.7 months (95% CI, 14.1 to 23.3 months; difference not statistically significant, P = .091). Median time to progression significantly favored simultaneous chemoradiotherapy (11.5 months; 95% CI, 8.3 to 14.7 months) versus radiotherapy alone (6.3 months; 95% CI, 5.0 to 7.6 months; P < .001, log-rank test).

Conclusion

Induction chemotherapy followed by chemoradiotherapy with weekly paclitaxel is feasible. Response, time to progression, and survival favor chemoradiotherapy compared with radiotherapy alone.

A phase II study of Yondelis (trabectedin, ET-743) as a 24-h continuous intravenous infusion in pretreated advanced breast cancer

Yondelis® (trabectedin, ET-743) is a novel marine-derived anticancer compound found in the ascidian Ecteinascidia turbinata. It is currently under phase II/III development in breast cancer, hormone refractory prostate cancer, sarcomas and ovarian cancer. Activity in breast cancer experimental models has been reported, and preliminary evidence of activity in this setting during the phase I programme has also been observed. The present study assessed the activity and feasibility of trabectedin in women with advanced breast cancer previously treated with conventional therapies. Patients with advanced disease previously treated with at least one but not more than two regimens that included taxanes or anthracyclines as palliative therapy were eligible. Trabectedin 1.5 mg m⁻² was administered as a 24-h continuous infusion every 3 weeks. Patients were kept on therapy until disease progression, unacceptable toxicity or patient refusal. Twenty-seven patients were included between April 1999 and September 2000. Their median age was 54 years (range: 36–67) and 63% of them had two metastatic sites. Twenty-two patients were performance status 1. All patients had previously received anthracyclines, and 23 out of 27 patients had received taxanes. Of 21 patients with measurable disease, three confirmed partial responses, one unconfirmed partial response and two minor responses (49 and 32% tumour shrinkage) were observed; six patients had stable disease. Median survival was 10 months (95% confidence interval: 4.88–15.18). Transient and noncumulative transaminitis was observed in most of the patients. The pharmacokinetic profile of trabectedin in this patient's population is in line with the overall data available with this schedule. The policy of dose adjustments based on the intercycle peaks of bilirubin and alkaline phosphatase appears to have a positive impact in the therapeutic index of trabectedin. Trabectedin can induce response and tumour control in previously treated advanced breast cancer, with manageable toxicity, thus warranting further development as a single agent or in combination regimens.