The effect on survival of initial chemotherapy in advanced breast cancer: polychemotherapy versus single drug

Epirubicin-Vinorelbine Intravenous Combination Followed by Oral Vinorelbine as First-Line Treatment in Metastatic Breast Cancer

Epirubicin and vinorelbine are considered active drugs in metastatic breast cancer. The optimal duration of a chemotherapy regimen for metastatic breast cancer patients is still unknown. Nevertheless, epirubicin has a dose-limiting cardiotoxicity. Vinorelbine is also available as oral formulation. In a multicenter phase II study, we analyzed the feasibility and the efficacy of a maximum of six cycles of i.v. epirubicin plus vinorelbine, followed by oral vinorelbine. We enrolled 30 patients with metastatic breast cancer. Each patient received epirubicin (75 mg/m2 on day 1) and vinorelbine (25 mg/m2 on days 1–8), every 3 weeks, for three cycles or six cycles in case of objective response or stable disease. When a clinical benefit was obtained, patients received oral vinorelbine (60 mg/m2 on days 1–8 every 3 weeks for three cycles). The regimen demonstrated to be active and well tolerated in metastatic breast cancer, and 6–8 months represented the optimal treatment duration. Maintenance therapy with oral vinorelbine was feasible, effective, safe and well accepted by the patients.

Intravenous versus oral vinorelbine plus capecitabine as second-line treatment in advanced breast cancer patients. A retrospective comparison of two consecutive phase II studies

Vinorelbine (i.v.) plus capecitabine (oral) combination therapy is active in anthracycline/taxane pretreated patients with metastatic breast cancer. Availability of oral vinorelbine provides this combination in an all-oral formulation. Two consecutive phase II trials differing only in vinorelbine administration routes evaluated their respective activities and tolerabilities in this population. In the i.v. group (n = 38) disease control was 61% (37% PR, 24% SD), median TTP 6.8 months and median survival 11.3 months. In the oral group (n = 38) disease control was 77% (5.4% CR, 34% PR, 38% SD), median TTP 7 months and median survival 10 months. G3-G4 neutropenia was more common in the oral group (p < 0.05); G2-G3 anaemia [5] and G3 thrombocytopenia [1] were observed only in the oral group. Although the comparison between the two regimens was not randomized, the results observed in these two consecutive phase II studies may suggest that oral and iv vinorelbine, in combination with capecitabine, can achieve similar responses in patients with metastatic breast cancer refractory to anthra-taxane combinations.

Single agent versus combination chemotherapy for metastatic breast cancer

BACKGROUND

Combination chemotherapy regimens are frequently favoured over single agents for the treatment of metastatic breast cancer, in an attempt to achieve superior tumour response rates. It is not known however whether giving more intensive chemotherapy regimens results in better health outcomes, when both survival and toxicity are considered, and whether better response rates and rates of progression free survival actually translate to better overall survival.

OBJECTIVES

To compare single agent with combination chemotherapy for the treatment of metastatic breast cancer.

SEARCH STRATEGY

We searched the Cochrane Breast Cancer Group Specialised Register November 2008. Handsearching of recent conference proceedings was also undertaken.

SELECTION CRITERIA

Randomised trials of single agent chemotherapy compared to combination therapy in metastatic breast cancer.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials for eligibility and quality, and extracted data. Hazard ratios were derived for reported time-to-event outcomes.Response rates were analysed as dichotomous variables. Toxicity and quality of life data were extracted where present.

MAIN RESULTS

Forty three eligible trials (48 comparisons) were identified. These included 9742 women, 55% of whom were receiving first-line treatment for metastatic disease. For overall survival there was a statistically significant difference in favour of the combination regimens with no heterogeneity (HR 0.88, 95% CI 0.83-0.93, p<0.00001). Results were very similar when trials of first-line treatment were analysed, and for analyses where the single agent was also included in the combination regimen. Combination regimens showed a statistically significant advantage for survival over single agent taxane (HR 0.82; 95% CI 0.75-0.89, p<0.00001), but not anthracycline (HR 0.94.86-1.02, p=0.15).Combination regimens were also associated with significantly better time to progression (HR 0.78, 95% CI 0.74 - 0.82, p<0.00001) and response (RR 1.29, 95% CI 1.14 -1.45, p<0.0001) although heterogeneity was statistically significant in both instances and probably due to clinical diversity of the participants and interventions.Women receiving combination regimens experienced a statistically significant detrimental effect on white cell count, increased alopecia and nausea and vomiting.

AUTHORS' CONCLUSIONS

Combination chemotherapy regimens show a statistically significant advantage for survival, tumor response and time to progression in women with metastatic breast cancer but they also produce more toxicity. An unresolved question is whether combination regimens are more effective than single agents given sequentially.

Multiple-treatments meta-analysis of chemotherapy and targeted therapies in advanced breast cancer

BACKGROUND

Many systemic nonhormonal regimens have been evaluated across several hundreds of randomized trials in advanced breast cancer. We aimed to quantify the relative merits of these regimens in prolonging survival.

METHODS

We performed a systematic review of all trials that compared different regimens involving chemotherapy and/or targeted therapy in advanced breast cancer (1973-2007). Regimens were categorized a priori into different treatment types. We performed multiple-treatments meta-analysis and calculated hazard ratios for each treatment category relative to monotherapy with old agents (ie, regimens not including anthracyclines, anthracenediones, vinorelbine, gemcitabine, capecitabine, taxanes, marimastat, thalidomide, trastuzumab, lapatinib, or bevacizumab).

RESULTS

We identified 370 eligible randomized trials (54,189 patients), of which 172 (31,552 patients) compared different types of treatment. Survival data from 148 comparisons pertaining to 128 of the 172 trials (26,031 patients, 22 different types of treatment) were available for inclusion in the multiple-treatments meta-analysis. Compared with single-agent chemotherapy with old nonanthracycline drugs, anthracycline regimens achieved 22%-33% relative risk reductions in mortality (ie, hazard ratio [HR] for standard-dose anthracycline-based combination: 0.67, 95% credibility interval [CrI] 0.57-0.78). Several newer regimens achieved further benefits (eg, HR [95% CrI] 0.67 [0.55-0.81] for single-drug taxane, 0.64 [0.53-0.78] for combination of anthracyclines with taxane, 0.49 [0.37-0.67] for taxane-based combination with capecitabine or gemcitabine), and similar benefits were seen with several regimens including molecular targeted treatments. Most regimens had very similar efficacy profiles (<5% difference in HR) as first- and subsequent-line therapies.

CONCLUSIONS

Stepwise improvements in efficacy of chemotherapy and targeted treatments cumulatively have achieved major improvements in the survival of patients with advanced breast cancer. Many options that can be used in first and subsequent lines of therapy have comparable efficacy profiles.

Oral vinorelbine plus capecitabine (oral vincap) combination in patients with advanced breast cancer (ABC). A phase II study of the GOIM (Gruppo Oncologico dell'Italia Meridionale)

BACKGROUND

Vinorelbine i.v. and capecitabine are two of the most effective single agents in previously treated advanced breast cancer (ABC). A number of studies have been reported with the combination of these agents. Actually, the availability of oral formulation for vinorelbine allows a full oral combination of the two agents. The aim of this study was to evaluate the activity and toxicity of this novel combination.

PATIENTS AND METHODS

Thirty-eight advanced breast cancer patients refractory to anthracyclines and taxanes were included in this study. Treatment consisted of vinorelbine 60 mg/m(2) (days 1 + 8), and capecitabine 2000 mg/m(2) (days 2-7 and 9-16) every 3 weeks.

RESULTS

A total of 228 courses were given with a mean of three cycles/patient (range 1-12). Five patients (13.1%) had no toxicity at all. Hematologic side-effects were: neutropenia grade 2-3 in seven patients (18.9%) and grade 4 in one patient (2.7%), anemia grade 1 in 11 patients (29.7%), grade 2-3 in five patients (13.5%), thrombocytopenia grade 1 in six patients (16.2%) and grade 3 in one patient (2.7%). Non-hematologic side-effects were: fatigue grade 1 in five patients (13.5%), hand-foot syndrome grade 1 in two patients (5.4%) and grade 2 in two patients (5.4%), nausea/vomiting grade 1 in two patients (5.4%), grade 2 in three patients (8.1%) and grade 3 in one patient (2.7%), constipation grade 1 in two patients (5.4%), peripheral neurotoxicity grade 1 in three patients (8.1%) and grade 2 in one patient (2.7%), gastric pain grade 1 in two patients (5.4%), stomatitis grade 1 in three patients (8.1%) and grade 2 in one patient (2.7%). Out of 38 patients assessable, we observed two (5.4%) CR, 13 (34 %) PR, 14 (37.8%) SD and nine (26.3%) PD. The median time to progression was 4.5 months (range 1-18 months), the median response duration was 7 months (range 2-18 months) and the median survival duration was 10 months (range 2-26+).

CONCLUSIONS

The oral vincap should be considered as an alternative to single agent capecitabine or vinorelbine in ABC refractory to antra-taxane combination.

Achievements in systemic therapies in the pregenomic era in metastatic breast cancer

Over the last decades, the introduction of several new agents into clinical practice has significantly improved disease control and obtained some, albeit rare, survival benefits in metastatic breast cancer (MBC). Despite these results, the choice of treatment for the majority of patients is still empirically based, since the only two predictive factors with level 1 evidence for clinical use are hormonal receptor status for endocrine therapy and HER-2 status for trastuzumab therapy. Important improvements in the endocrine therapy of both pre- and postmenopausal women with hormone-responsive disease have been achieved. For premenopausal women, ovarian function suppression with luteinizing hormone-releasing hormone analogs combined with tamoxifen has become the standard treatment, although aromatase inhibitors plus ovarian function suppression are under evaluation. In postmenopausal patients, aromatase inhibitors have proved to be superior to standard endocrine therapies in either first- or second-line treatment and a novel antiestrogen compound, fulvestrant, has been introduced in clinical practice. Chemotherapy remains the treatment of choice for hormone unresponsive or resistant patients. Anthracyclines and taxanes have been used either alone or in combination as first-line chemotherapy, but with the more frequent use of these agents in the adjuvant setting, new standards are needed for first-line chemotherapy, and new and more efficacious treatments are required. In the subgroup of patients with tumors that overexpress HER-2, the use of trastuzumab alone or in combination with chemotherapy has modified the natural history of these tumors, even if only about one out of two patients obtains a clinical response. In this review we summarize the main achievements and the currently available treatment options for patients with MBC.

Survival Differences Observed in Metastatic Breast Cancer Patients Treated With Capecitabine When Compared With Vinorelbine After Pretreatment With Anthracycline and Taxane

OBJECTIVES

The optimal treatment of metastatic breast cancer patients previously treated with anthracycline and taxane is unknown. Common therapeutic alternatives include capecitabine and vinorelbine. This retrospective chart review compares overall survival following treatment with capecitabine, vinorelbine, or both agents sequentially in this group of women.

PATIENTS AND METHODS

Electronic patient records and charts of patients who received anthracycline and taxane-based chemotherapy and subsequently received capecitabine and/or vinorelbine at 3 Canadian cancer centers, between November 1994 and June 2003, were retrospectively reviewed.

RESULTS

A total of 140 patients met the study eligibility criteria: 45 patients received vinorelbine as a single agent and 68 received capecitabine as a single agent. The median duration of therapy was 64 days with vinorelbine and 129 days with capecitabine (P = 0.0012). Median overall survival was 102 days for the vinorelbine group and 188 days for the capecitabine group (P < 0.0001). Survival at 1 year was 15.6% for the vinorelbine group and 28.4% for the capecitabine group (P = 0.017). Twenty-seven patients received both agents sequentially; and in this group, the median duration of therapy was 110 days (87 days with vinorelbine and 138 days with capecitabine), and the median overall survival was 390 days.

CONCLUSIONS

This exploratory analysis suggests that patients with tumors previously treated with both anthracycline and taxane can still obtain significant survival benefit from further chemotherapy. The results indicate that capecitabine may be superior to vinorelbine in this setting.

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

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/m(2)) 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 >or=20 units or a decline to <or=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.

Single agent versus combination chemotherapy for metastatic breast cancer

BACKGROUND

It is commonly thought that combining chemotherapy agents for treating women with metastatic breast cancer will result in regimens that are more active, offer superior tumour response rates with more time before progression and improve overall survival. However, it is not known whether giving patients more intensive chemotherapy regimens (judged according to some measure eg dose, dose intensity, response rate, or toxicity) results in better health outcomes. One way to investigate the effect of more versus less-intensive chemotherapy is to compare regimens containing a single drug (and hence possibly less active treatment) with regimens containing a greater number of drugs (and hence possibly more active but more toxic), even when adjustments are made to dosages or schedules to account for toxicity.

OBJECTIVES

To compare use of single chemotherapy agents with regimens containing a combination of agents for the treatment of metastatic breast cancer.

SEARCH STRATEGY

The Specialised Register maintained by the Editorial Base of the Cochrane Breast Cancer Group was searched on 2nd May 2003 using the codes for "advanced breast cancer", "chemotherapy". Details of the search strategy applied by the group to create the register, and the procedure used to code references, are described in the group's module on The Cochrane Library.

SELECTION CRITERIA

Randomised trials comparing single agent chemotherapy with combination therapy in women with metastatic breast cancer.

DATA COLLECTION AND ANALYSIS

Data were collected from published trials. Studies were assessed for eligibility and quality, and data were extracted by two independent reviewers. Hazard ratios were derived for time-to-event outcomes where possible, and a fixed effect model was used for meta-analysis. Response rates were analysed as dichotomous variables. Toxicity and quality of life data were extracted where present.

MAIN RESULTS

Thirty seven eligible trials were identified of which 28 had published time-to-event data. The quality of randomisation was generally not described. Data, based on an estimated 4220 deaths in 5707 women, show a modest advantage for combination chemotherapy regimens compared with single agents with a hazard ratio (HR) for overall survival of 0.88 (95% CI=0.83-0.94, P<0.0001) and no evident heterogeneity. Results are similar if the analysis is limited to trials in women receiving first-line chemotherapy. Combination regimens are favourably associated with time to progression (overall HR of 0.78 (95% CI=0.73-0.83, P<0.00001) and tumour response rates (OR 1.28, CI=1.15-1.42, P<0.00001) although significant heterogeneity was observed (P=0.002 and P<0.00001 respectively). This probably reflects the varying efficacy of the comparator regimens used in the trials. Women receiving combination regimens experienced a higher toxicity level for leukopenia, hair loss and nausea and vomiting compared with those receiving a single agent, which was statistically significant.

AUTHORS' CONCLUSIONS

Compared with single-chemotherapy agents, combination regimens show a statistically significant advantage for tumor response and time to progression in women with metastatic breast cancer, a modest improvement in overall survival and significantly worse toxicities.

The role of the liposomal anthracyclines and other systemic therapies in the management of advanced breast cancer

For patients whose breast cancers are not responsive to endocrine therapy, there are a large number of cytotoxic drugs that will induce a response. In spite of the introduction of new, very active drugs such as the taxanes, vinorelbine, capecitabine, gemcitabine, and trastuzumab, the anthracyclines are still as active as any--and more active than most--drugs used to treat breast cancer. Their inclusion in combinations to treat early and advanced disease prolongs survival. However, they cause nausea, vomiting, alopecia, myelosuppression, mucositis, and cardiomyopathies. There is no evidence that increasing the dose of conventional anthracyclines or any other of the cytotoxics beyond standard doses will improve outcomes. Schedule may be more important than dose in determining the benefit of cytotoxics used to treat breast cancer. Weekly schedules and continuous infusions of 5-fluorouracil and doxorubicin may have some advantages over more intermittent schedules. Liposomal formations of doxorubicin reduce toxicity, including cardiotoxicity; theoretically they should also be more effective because of better targeting of tumor over normal tissues. Both pegylated liposomal doxorubicin (Doxil/Caelyx [PLD]) and liposomal doxorubicin (Myocet [NPLD]) appeared to be as effective as conventional doxorubicin and much less toxic in multiple phase II and phase III studies. PLD has been evaluated in combinations with cyclophosphamide, the taxanes, vinorelbine, gemcitabine, and trastuzumab, and NPLD has been evaluated in combination with cyclophosphamide and trastuzumab. Both liposomal anthracyclines are less cardiotoxic than conventional doxorubicin. The optimal dose of PLD is lower than that of conventional doxorubicin or NPLD. Patients treated with PLD have almost no alopecia, nausea, or vomiting, but its use is associated with stomatitis and hand-foot syndrome, which can be avoided or minimized with the use of proper dose-schedules. In contrast, the optimal dose-schedule of NPLD is nearly identical to that of conventional doxorubicin. The toxicity profile of NPLD is similar to that of conventional doxorubicin, but toxicities are less severe and NPLD is better tolerated than conventional doxorubicin at higher doses.

Antitumour antibiotic containing regimens for metastatic breast cancer

BACKGROUND

Antitumour antibiotics are used in the management of metastatic breast cancer. Some of these agents have demonstrated higher tumour response rates than non-antitumour antibiotic regimens, however a survival benefit has not been established in this setting.

OBJECTIVES

To identify and review the randomised evidence comparing anti-tumour antibiotic containing chemotherapy regimens with regimens not containing an anti-tumour antibiotic in the management of women with metastatic breast cancer.

SEARCH STRATEGY

The specialised register maintained by the Editorial Base of the Cochrane Breast Cancer Group was searched on 2nd May, 2003 using the codes for "advanced breast cancer" and "chemotherapy". Details of the search strategy and coding applied by the Group to create the register are described in the Group's module on The Cochrane Library.

SELECTION CRITERIA

Randomised trials comparing anti-tumour antibiotic containing regimens with regimens not containing anti-tumour antibiotics in women with metastatic breast cancer.

DATA COLLECTION AND ANALYSIS

Data were collected from published trials. Studies were assessed for eligibility and quality, and data were extracted by two independent reviewers. Hazard ratios (HRs) were derived from time-to-event outcomes where possible, and a fixed effect model was used for meta-analysis. Response rates were analysed as dichotomous variables. Quality of life and toxicity data were extracted where present. A primary analysis was conducted for all trials and by class of antitumour antibiotic.

MAIN RESULTS

Thirty-three trials reporting on 45 treatment comparisons were identified. All trials published results for tumour response and 26 trials published time-to-event data for overall survival. The observed 4084 deaths in 5284 randomised women did not demonstrate a statistically significant difference in survival between regimens that contained antitumour antibiotics and those that did not (HR 0.97, 95% CI 0.91 to 1.03, P = 0.35) and no significant heterogeneity. Antitumour antibiotic regimens were favourably associated with time-to-progression (HR 0.84, 95% CI 0.77 to 0.91) and tumour response rates (odds ratio (OR) 1.34, 95% CI 1.21 to 1.48) although statistically significant heterogeneity was observed for these outcomes. These associations were consistent when the analysis was restricted to the 29 trials that reported on anthracyclines. Patients receiving anthracycline-containing regimens were also more likely to experience toxic events compared to patients receiving non-antitumour antibiotic regimens. No statistically significant difference was observed in any outcome between mitoxantrone-containing and non-antitumour antibiotic-containing regimens.

REVIEWERS' CONCLUSIONS

Compared to regimens without antitumour antibiotics, regimens that contained these agents showed a statistically significant advantage for tumour response and time to progression in women with metastatic breast cancer but were not associated with an improvement in overall survival. The favourable effect on tumour response and time to progression observed in anthracycline-containing regimens was also associated with greater toxicity.

A phase I study of capecitabine in combination with vinorelbine in advanced breast cancer

A phase I study was conducted in order to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) of the combination of vinorelbine and capecitabine in patients affected with metastatic breast cancer. Eighteen patients with histologically confirmed advanced breast cancer, who had failed =1 prior chemotherapy regimen, were enrolled. The median age was 56 years (range, 39-70 years). All but 1 had previously received a combination of anthracyclines and taxanes; performance status (Eastern Cooperative Oncology Group) was 0/1 or 2 in 13 and 5 patients, respectively. Vinorelbine was administered at a fixed dosage of 25 mg/m2 on days 1 and 8 every 3 weeks. Capecitabine was administered orally, at an escalated dose ranging from 1400 mg/m2 to 2250 mg/m2 for 14 consecutive days starting on day 1 of the cycle, divided into 2 daily doses delivered half an hour after eating at 12-hour intervals. Three patients were treated at each dose level: if 1 patient developed a DLT, an additional 3 patients were treated at the same dose level. If 2 additional patients experienced DLT, no further escalation was allowed and the previous dose level was declared MTD. Dose-limiting toxicity was reached at 2250 mg/m2 of capecitabine with 3 out of 3 patients experiencing grade 4 neutropenia plus grade 3 diarrhea and grade 3 oral mucositis in 1 patient). Thus, MTD was defined at 2000 mg/m2 capecitabine. Other observed grade 2 side effects were: 1 patient with neutropenia, 1 with hand-foot syndrome, 2 with mucositis, 1 with cutaneous rash, and 1 with thrombocytopenia. With regard to response rate, we observed 1 complete response (5.5%), 6 partial responses (33%), and 4 disease stabilizations (22%). The median time to progression was 12 weeks and the median survival 41 weeks. The MTD of capecitabine in combination with vinorelbine at 25 mg/m2 dosage on days 1 and 8 of a 3-week schedule is 2000 mg/m2/day for 14 consecutive days. Moreover, this regimen showed interesting activity with 61% overall disease control (complete plus partial response plus disease stabilization) in patients pretreated with anthracyclines and taxanes warranting further investigations in a large, multicenter phase II study.

Phase III trial of doxorubicin, paclitaxel, and the combination of doxorubicin and paclitaxel as front-line chemotherapy for metastatic breast cancer: an intergroup trial (E1193)

PURPOSE

Between February 1993 and September 1995, 739 patients with metastatic breast cancer were entered on an Intergroup trial (E1193) comparing doxorubicin (60 mg/m(2)), paclitaxel (175 mg/m(2)/24 h), and the combination of doxorubicin and paclitaxel (AT, 50 mg/m(2) and 150 mg/m(2)/24 h, plus granulocyte colony-stimulating factor 5 mg/kg) as first-line therapy. Patients receiving single-agent doxorubicin or paclitaxel were crossed over to the other agent at time of progression.

PATIENTS AND METHODS

Patients were well balanced for on-study characteristics.

RESULTS

Responses (complete response and partial response) were seen in 36% of doxorubicin, 34% of paclitaxel, and 47% of AT patients (P =.84 for doxorubicin v paclitaxel, P =.007 for v AT, P =.004 for paclitaxel v AT). Median time to treatment failure (TTF) is 5.8, 6.0, and 8.0 months for doxorubicin, paclitaxel, and AT, respectively (P =.68 for doxorubicin v paclitaxel, P =.003 for doxorubicin v AT, P =.009 for paclitaxel v AT). Median survivals are 18.9 months for patients taking doxorubicin, 22.2 months for patients taking paclitaxel, and 22.0 months for patients taking AT (P = not significant). Responses were seen in 20% of patients crossing from doxorubicin --> paclitaxel and 22% of patients crossing from paclitaxel --> doxorubicin (P = not significant). Changes in global quality-of-life measurements from on-study to week 16 were similar in all three groups.

CONCLUSION

(1) doxorubicin and paclitaxel, in the doses used here, have equivalent activity; (2) the combination of AT results in superior overall response rates and time to TTF; and (3) despite these results, combination therapy with AT did not improve either survival or quality of life compared to sequential single-agent therapy.

Is first-line single-agent mitoxantrone in the treatment of high-risk metastatic breast cancer patients as effective as combination chemotherapy? No difference in survival but higher quality of life were found in a multicenter randomized trial

BACKGROUND

To determine whether patients with high-risk metastatic breast cancer draw benefit from combination chemotherapy as first-line treatment.

PATIENTS AND METHODS

A total of 260 women with measurable metastatic breast cancer fulfilling high-risk criteria, previously untreated with chemotherapy for their metastatic disease, were randomized to receive either mitoxantrone 12 mg/m(2) or the combination of fluorouracil 500 mg/m(2), epirubicin 50 mg/m(2) and cyclophosphamide 500 mg/m(2) (FEC) every 3 weeks. Treatment was continued until complete remission plus two cycles, or until disease progression. In the case of partial remission or stable disease, treatment was stopped after 12 cycles. Second-line treatment was vindesine, mitomycin and prednisolone. Gain from treatment was estimated using a modified Brunner's score composed of time to progression, patients' rating of the treatment benefit, alopecia, vomiting and performance status.

RESULTS

After recruitment from 1992 to 1997 and observation from 1997 to 1999, the final evaluation showed that single-agent treatment with mitoxantrone does not differ significantly from combination treatment with FEC in terms of response, objective remission rate, remission duration, time to response, time to best response, time to progression or overall survival. There was, however, a significant difference in gain from treatment using a modified Brunner's score favoring the single-agent treatment arm. There was no evidence that any subgroup would fare better with combination treatment.

CONCLUSIONS

No significant difference was detected between the treatment with mitoxantrone as a single agent and the combination of low-dose FEC in terms of response or survival; therefore, the imperative of the necessity of first-line combination chemotherapy for patients with high-risk metastatic breast cancer may be questioned. Since toxicity and quality of life score favored the single-agent mitoxantrone treatment arm, this treatment may be offered to patients preferring quality of life to a potential small prolongation of survival.

Epirubicin versus CMF as adjuvant therapy for stage I and II breast cancer: a prospective randomised study

We compared a relatively short regimen of monochemotherapy with epirubicin versus polychemotherapy with CMF (cyclophosphamide, methotrexate, 5-fluorouracil) as adjuvant treatment for stage I and II breast cancer patients. 348 patients with oestrogen receptor negative (ER-) node negative and ER- or ER+ node-positive with <10 nodes were accrued. CMF was given intravenously (i.v.) on days 1 and 8, every 4 weeks, for six courses; epirubicin was given weekly for 4 months. Postmenopausal patients received tamoxifen for 3 years. The primary endpoints were overall survival (OS), relapse-free survival (RFS) and event-free survival (EFS). Outcome evaluation was performed both in eligible patients and in all randomised patients according to the intention-to-treat principle. 8 randomised patients were considered ineligible. At a median follow-up of 8 years, there was no difference in OS (Hazard Ratio (HR)=1.11, 95% Confidence Interval (CI): 0.77-1.61, P=0.58), EFS (HR=1.14, 95% CI: 0.78-1.64, P=0.48), and RFS (HR=1.14, 95% CI: 0.8-1.64, P=0.48) between the two arms for all of the patients. At 8 years, the RFS percentages (+/-Standard Error (S.E.)) were 65.4% (+/-4%) in the CMF arm and 62.7% (+/-4%) in the epirubicin arm; for EFS these were 64.2% (+/-4%) for CMF and 60.8% (+/-4%) for epirubicin, respectively. A significant difference in RFS (P=0.015) was observed in patients with 4-9 positive nodes in favour of the CMF arm. Toxicity in the two arms was superimposable except for more frequent grade 3 alopecia in the epirubicin-treated patients (P=0.001). Overall, at a median follow-up of 8 years, there were no differences between the two arms in terms of OS, EFS and RFS.

First-line treatment with epirubicin and vinorelbine in metastatic breast cancer

PURPOSE

This phase II multicenter trial was aimed at investigating the activity of epirubicin-vinorelbine combination as first-line chemotherapy in metastatic breast cancer patients.

PATIENTS AND METHODS

Ninety-seven patients with metastatic breast cancer and no prior exposure to anthracyclines received the following regimen: epirubicin 100 mg/m(2) by intravenous (IV) bolus infusion on day 1 plus vinorelbine 25 mg/m(2) by 30-minute IV infusion on days 1 and 5, every 3 weeks for up to eight cycles. All patients also received granulocyte colony-stimulating factor (G- CSF) on days 7 to 12 of every cycle.

RESULTS

Objective responses, confirmed at least 4 weeks after the first documentation, were observed in 65 out of 92 assessable patients (70.6%; 95% CI, 62% to 80%). Disease remained stable in 17 patients (18.5%). Responses were observed in all disease sites, being 94% in soft tissue, 60% in bone, and 66% in visceral disease. Median time to response, median duration of response, median time to progression, and median overall survival were 2, 9, 10, and 26 months, respectively. The dose-limiting toxicity was neutropenia, which was grade 4 in 36% of the patients, and was accompanied by fever in 26% of the cases. Grade 3 to 4 mucositis was encountered in 28% of the patients. Other toxicities were mild to moderate. No cardiotoxicity was observed.

CONCLUSION

The epirubicin-vinorelbine combination with G-CSF support has been shown in this study to be highly active as first-line treatment of metastatic breast cancer patients, with significant although transient toxicity. This justifies further evaluation in the neoadjuvant setting and in early-stage breast cancer.

Does a drug do better when it is new?

BACKGROUND

When assessing a new, promising therapeutic approach, a clinician's perception of a drug's effectiveness may be shaped by different kinds of phenomena, and among them, a favorable attitude towards new treatments, and as a result a tendency to overestimate their efficacy (wish bias).

MATERIALS AND METHODS

A retrospective study of published randomized clinical trials of doxorubicin-based chemotherapy for advanced breast cancer was carried out. Global (complete plus partial) response rate over time with allowance for type of drug regimen (mono- or polychemotherapy) and prior adjuvant therapies was assessed in the doxorubicin-containing arm using multivariate logistic regression analysis.

RESULTS

Twenty-nine studies published from 1975 to 1999 were retrieved for a total of 2234 women with advanced breast cancer enrolled in the doxorubicin-containing arms. There was a significant decrease in response rate to doxorubicin as first-line treatment over time that resisted adjustment for important differences in therapeutic management [odds ratio for global response = 0.89, 95% confidence interval (CI) 0.81 to 0.99].

CONCLUSIONS

Although only one drug (doxorubicin) in one clinical context (advanced breast cancer) has been analyzed, our findings support the use of double blind methodology whenever possible when assessing subjective endpoints and encourage further studies aimed at defining the clinical relevance of a wish bias in medicine.

Phase III comparative study of vinorelbine combined with doxorubicin versus doxorubicin alone in disseminated metastatic/recurrent breast cancer: National Cancer Institute of Canada Clinical Trials Group Study MA8

PURPOSE

This phase III study was performed to determine the superiority of doxorubicin (DOX) and vinorelbine (VNB) (arm 1) versus DOX alone (arm 2) in metastatic breast cancer (MBC) for overall survival (OS), time to treatment failure (TTF), toxicity, and quality of life (QOL).

PATIENTS AND METHODS

Three hundred three patients were randomized to DOX 50 mg/m(2) intravenously (IV) on day 1 and VNB 25 mg/m(2) IV on days 1 and 8 (arm 1) or DOX 70 mg/m(2) IV on day 1 (arm 2). Both regimens were given every 3 weeks until a cumulative DOX dose of 450 mg/m(2). After 16 of the first 65 randomized patients experienced febrile neutropenia (FN), the doses were reduced to DOX 40 mg/m(2) on day 1 and VNB 20 mg/m(2) on days 1 and 8 versus DOX 60 mg/m(2) on day 1. Eligible patients were vinca alkaloid and anthracycline naive. Chemotherapy was first-line or second-line for MBC.

RESULTS

Three patients were ineligible. Thus, 300 patients were assessable for toxicity and to determine time to disease progression (TTP), TTF, and OS. Two hundred eighty-nine patients were assessable for response, and 99 responders were assessable for response duration (RD). The response rates, QOL, and median RD, TTP, and TTF were not significantly different between the arms. Median OS was 13.8 months for arm 1 versus 14.4 months for arm 2 (P =.4). Grade 3 or 4 granulocytopenia was equivalent in both arms but more grade 3/4 neurotoxicity, mild venous toxicity, and FN were seen on arm 1.

CONCLUSION

The survival with DOX and VNB is not superior to DOX alone in MBC.

The intracellular histamine antagonist, N,N-diethyl-2-[4-(phenylmethyl)phenoxy] ethamine.HCL, may potentiate doxorubicin in the treatment of metastatic breast cancer: Results of a pilot study

N,N-diethyl-2-[4-(phenylmethyl)phenoxy] ethanamine.HCl (DPPE) is a diphenylmethane analog of tamoxifen that antagonizes the intracellular binding of histamine to growth-regulatory sites, a proportion of which represents P450 enzymes, in microsomes and nuclei. We previously reported increased response rates and decreased myelotoxicity in patients with prostate and other cancers who received an intensive dose/schedule of DPPE plus single-agent chemotherapy. We now report the results of a study of DPPE combined with a standard dose/schedule of doxorubicin in twenty-three patients with metastatic breast cancer, sixteen of whom had received prior non-anthracycline chemotherapy. DPPE (6 mg/kg) was infused intravenously (i.v.) over 80 minutes. Doxorubicin (60 mg/m2) was administered i.v. over the last 20 minutes of the DPPE infusion. Treatment was repeated every 3 weeks (maximum, 7 cycles). Patients achieving complete response (CR) were followed off treatment until relapse. All patients were evaluable for toxicities and efficacy. Sixteen patients (69%; 95% C.I. = 47-87%) responded (7 CR and 9 PR). Eleven responders, including 6 with CR, had prior chemotherapy. Five responders (2CR, 3PR) had a poor (ECOG 3/4) performance status pre-treatment. Median CR duration was 11 (range 5-18) months. Hematological toxicity was low; GI toxicity (nausea/vomiting/dyspepsia) appeared somewhat higher than historical experience, but responded well to anti-emetics, ranitidine, and/or dexamethasone in most patients; a mean absolute drop in left ventricular ejection fraction of 8% occurred in 17 patients who received = or > 300 mg/m2 doxorubicin. The observed response rate in DPPE/doxorubicin-treated patients appeared to be higher than historically reported for doxorubicin alone in this setting, suggesting a chemopotentiating effect of DPPE. A multi-centre trial of this regimen in an additional 32 patients with early metastatic breast cancer has been conducted by the Clinical Trials Group, National Cancer Institute of Canada, and a phase 3 study is planned.

Heterogeneity of in vitro chemosensitivity in perioperative breast cancer cells to mitoxantrone versus doxorubicin evaluated by a microplate ATP bioluminescence assay

Apart from clinical trials, mitoxantrone (MX) is rarely used in breast cancer (BC) due to the anticipated anthracycline cross-resistance. We have examined this drug versus doxorubicin (DOX) using data obtained from in vitro microplate ATP tumor chemosensitivity assays (ATP-TCA) of BC cells which were derived from 55 chemotherapy-naive patients at time of primary surgery. Both drugs were tested at 6 different concentrations ranging from 6.25% to 200% peak plasma concentration in vivo (PPC). Differences between DOX and MX observed for mean IC50, IC90, and a sensitivity index (SI) were not statistically significant. In vitro response rates were 44% for DOX and 52% for MX. 34 of 52 eligible assays (65%) showed comparable activity of both drugs whereas a lack of cross-resistance was observed in the remaining 18 (35%) tumors as indicated by differences for SI. Cumulative concentration-response plots of tumors responding in vitro with a > or = 50 percent or > or = 90 percent tumor cell inhibition showed a strong dose-dependence for both DOX and MX at concentrations which normally can be achieved within clinical tumors (i.e. 6.25%-50% PPC). At higher concentrations, however, cytotoxicity of DOX and MX could not be improved by further in vitro dose escalation. Moreover, a substantial proportion of BC specimens (DOX: 48.1%; MX: 40.4%) did not experience a > or = 90 tumor cell inhibition at 200% PPC. In conclusion, in vitro results obtained by ATP-TCA indicate that there is no cross-resistance between MX and DOX in a substantial proportion of BC patients. This may be clinically useful and suggests that combinations including MX should be tested in patients clinically resistant to DOX containing regimens. Since both drugs produced sigmoidal concentration-response curves, dose escalation beyond a certain point may not produce increased sensitivity.

Phase II trial of 5-fluorouracil and folinic acid in the treatment of advanced breast cancer

Standard combination chemotherapy for metastatic breast cancer produces response rates between 30-60% with limited impact on survival. We undertook a phase II trial to determine the activity of 5 fluorouracil (5FU) and folinic acid (FA) in patients with measurable metastatic or recurrent breast cancer who had received no prior chemotherapy. Patients meeting the eligibility criteria received 5FU 370 mg/m2/day and FA 200 mg/m2/day for 5 days repeated every 28 days, toxicity allowing. Response defined by standard criteria was assessed every 8 weeks and toxicity according to WHO criteria was determined on every course. Thirty-three patients were entered on trial. Thirty-two patients were evaluable for response and 33 for toxicity. The dose limiting toxicity was stomatitis with 7/32, 19/32, and 5/32 patients experiencing grade 1, 2, and 3 toxicity. Grades 1 and 2 diarrhea occurred in 17/32 and 11/32 patients respectively. Myelosuppression was not significant. Two complete and 11 partial responses were observed. The overall response rate was 41% (95% CI, 24-58%). Responses were seen in soft tissue and visceral sites. Patients who had received adjuvant chemotherapy more than 6 months prior to receiving 5FU and FA responded also. Six of 29 patients receiving standard combination chemotherapy as second line treatment responded subsequently. We concluded: 1) 5FU and FA is an active combination in the treatment of breast cancer warranting further evaluation in combination with other drugs; 2) the dose-limiting toxicity of stomatitis is tolerable; 3) patients receiving 5FU and FA as first line therapy can respond to conventional combination chemotherapy as second line treatment.

Managing breast cancer in an outpatient setting

The treatment of advanced breast cancer has undergone relatively little change in the past decade. Reasons for such a static situation are the sobering realization that even effective chemotherapeutic regimens have had a minor impact on survival, and the paucity of new effective agents that have been introduced since initial combination treatments. Based in part on this lack of progress, in recent years dose-intensification in search of a curative strategy has been widely adopted. Its role remains to be defined, but ultimately it is likely to be relegated to situations where tumor burdens have been effectively reduced. This reduction in burden may not currently be feasible in many advanced presentations. Outpatient efforts will therefore focus on the following: 1) employing single agents optimally (e.g. infusion 5-fluorouracil), 2) using regimens which integrate new drugs with activity (e.g. taxol), and 3) testing measures which may improve the quality of life (e.g. bisphosphonates in the presence of bone metastases). Although one cannot approach the treatment of advanced breast cancer with the (misplaced) optimism of two decades ago, the expanded armamentarium currently available should lead to a more rational application of chemotherapy. Treatments will increasingly be based on the biology of the cancer, and on the therapeutic index and action of the drugs.

Chemotherapy of advanced epithelial cancer--a critical review

This article is a short version of a report which presents a comprehensive analysis of clinical trials and publications examining the value of cytotoxic chemotherapy in the treatment of advanced epithelial cancer. As a result of the analysis and the comments received from hundreds of oncologists in reply to a request for information, the following facts can be noted. Apart from lung cancer, in particular small-cell lung cancer, there is no direct evidence that chemotherapy prolongs survival in patients with advanced carcinoma. Except for ovarian cancer, available indirect evidence rather supports the absence of a positive effect. In treatment of lung cancer and ovarian cancer, the therapeutical benefit is at best rather small, and a less aggressive treatment seems to be at least as effective as the usual one. It is possible that certain sub-groups of patients benefit from the treatment, yet so far the available results do not allow a sufficiently precise definition of these groups. Many oncologists take it for granted that response to therapy prolongs survival, an opinion which is based on a fallacy and which is not supported by clinical studies. To date, it is unclear whether the treated patients, as a whole, benefit from chemotherapy as to their quality of life. For most cancer sites, urgently required types of studies such as randomized de-escalations of dose or comparisons of immediate versus deferred chemotherapy are still lacking. With few exceptions, there is no good scientific basis for the application of chemotherapy in symptom-free patients with advanced epithelial malignancy.

Indications for cytostatic therapy in metastatic breast cancer

Generalized breast cancer is always incurable. The heterogeneity of this disease is reflected by wide variation in treatment response and survival duration. No well-defined factors have been found which can distinguish the patients most likely to benefit from chemotherapy. No superior drug combination or schedule has been convincingly established, and basic facts on quality of life issues are still lacking. The most important treatment goal is to provide meaningful palliation for the individual patient. Indications for chemotherapy are life-threatening disease, distant metastases in receptor-negative disease, and clinically hormone resistant disease. In future trials the importance of potentially relevant biological factors for treatment should be evaluated, and such analyses should, at least partly, replace the presently conducted phase II and phase III studies.

Phase II study of deoxydoxorubicin in previously untreated metastatic breast cancer

With the objective of identifying new chemotherapeutic agents active against breast cancer, we administered the phase II agent deoxydoxorubicin (DxDx) to 25 patients who had received no prior chemotherapy for their metastatic breast cancer. A dose of 30-35 mg/M2 given at 3 week intervals resulted in a response rate of 12%. The patients were subsequently treated with a combination of 5-fluorouracil, methotrexate, vincristine, cyclophosphamide, and prednisone. A response rate of 38% was achieved with this combination as second line therapy. Toxicity of DxDx was predominantly hematopoietic. One patient developed congestive heart failure. Median survival from onset of treatment with DxDx was 39 weeks. DxDx appears to be minimally active against metastatic breast cancer. Whether the administration of phase II agents as first line therapy offers an advantage in the overall management of metastatic cancer, needs further evaluation.

Comprehensive management of disseminated breast cancer

The management of patients with metastatic breast cancer is best achieved by the judicious use of local and systemic measures that palliate symptoms and improve overall quality of life. When two treatment approaches are known to be equally efficacious, the less toxic should be used. When disease is limited to one or two sites and the patient has an indolent form of the disease, the patient's symptoms are often best palliated with the use of surgery or radiotherapy alone. When multiple sites of disease are evident or the disease is progressing more rapidly, systemic therapy is preferred, and local therapies should be added when the patient is clearly refractory to systemic therapy or when the disease site is unlikely to be adequately palliated with systemic therapy. The use of any of these therapies, including chemotherapy, has a relatively small effect on the median survival of patients with metastatic breast cancer. However, improvements in quality of life are usually greatest with regimens inducing the highest response rates, even when these regimens are associated with greater toxicity. The characteristics of patients likely to respond to endocrine therapy are well defined; in these patients endocrine therapy should be used as the first form of systemic therapy. Among endocrine therapies, the least toxic is used first. The selection of patients for chemotherapy is largely a process of exclusion. When chemotherapy is used, there are a number of different strategies for sequencing chemotherapy that appear to be equally efficacious. In general, patients should be treated with standard doses of drug combinations for a period in excess of 3 months. When used inappropriately, especially in asymptomatic patients, these therapies may actually compromise the patient's quality of life. The use of surgery, radiation therapy, and systemic therapy should be integrated with various types of psychosupport services, especially peer support groups. Patients who want to try new forms of therapy should do so early in the course of the disease when these therapies are most likely to be effective and the patient has the least to lose if the therapy proves ineffective. This is especially true because the use of the most effective regimens at a time when the patient is asymptomatic may mean that the patient is resistant to most or all therapies of proven value when most in need of palliation.

Identification of meta-analyses. The need for standard terminology

Our efforts to identify published articles describing meta-analyses of clinical trials illustrate the need for standard terminology to facilitate retrieval. We found 119 articles describing meta-analyses and eligible for inclusion in MEDLINE, and yet when we searched MEDLINE, using strategies based on textwords and medical subject headings (MeSH), only 48% of the 119 articles were identified. Sixty-eight (57%) of the 119 articles contained at least one of the terms "meta-analysis," "pooling," or "overview" in the title or abstract. The importance of meta-analyses in the evaluation of medical treatments argues for more disciplined use of a specific term in order to facilitate identification of articles. The fact that the National Library of Medicine has started in 1989 to index articles describing meta-analyses using the MeSH META-ANALYSIS underscores this argument.

Survival effect of systemic therapy on patients developing metastatic breast carcinoma

A multivariate analysis was performed to assess the effect of post-relapse systemic therapy on a series of patients with metastatic breast cancer who at initial presentation had no detectable metastases (Mo), were less than or equal to 70 years of age, presented with unilateral localized disease and no other associated malignancy, and were treated between 1965 and 1984 with successive protocols for primary disease and subsequently developed distant metastasis. All 760 patients analyzed relapsed with at least one metastasis, and were studied retrospectively with no selection criteria according to any specific protocol. All had recorded clinical data on menopause, stage, clinical tumor aggressiveness (PEV), initial chemo or hormonal therapy, and time to relapse, and had ongoing follow up at our Center, with salvage chemotherapy and/or hormonal therapy having been given to some but not all patients. A brief metastasis-free survival (p less than 0.000001), and factors associated with electing pre-relapse chemotherapy (p less than 0.000001) were associated with shortened post-relapse survival, while post-relapse therapy (chemo p less than 0.0001, and hormonal p less than 0.00001, replacing chemotherapy in the model) apparently increased post-relapse survival in the group overall. This result was similar in the inoperable patient group [with inflammatory breast carcinoma an additional risk factor (p less than 0.0005)], as well as the operable group. However, in the operable group, when the pathologic criteria of histologic grade and nodal status were introduced into the analysis, post-relapse therapy was not seen to be an important factor for survival in any subgroup.(ABSTRACT TRUNCATED AT 250 WORDS)

A prospective randomized trial of doxorubicin versus idarubicin in the treatment of advanced breast cancer

Seventy-six patients with advanced breast cancer were entered into the current study. They were randomized to receive either idarubicin (IDA) 45 mg/m2 orally or doxorubicin (DX) 75 mg/m2 intravenously (IV), both drugs being administered every 3 weeks. Among 37 evaluable patients who received DX treatment the overall response rate was 46%, whereas it was 21% in 34 evaluable patients treated with IDA. This difference was statistically significant. In previously untreated patients the response rate with DX was 60% compared to 29% with IDA. Patients with prior chemotherapy had 29% response rate to DX in contrast to 12% with IDA. The median time to response, the median response duration, and the median time to progression were similar in both groups. The median survival of all patients was 20 months in DX arm and 14 months in IDA arm (95% confidence limits 16.69-23.31 and 10.77-17.23, respectively; P = 0.09). Both treatments produced equivalent incidence and severity of myelotoxicity. Gastrointestinal toxicity and alopecia were significantly lower in patients receiving IDA. As for cardiotoxicity, four cases of congestive heart failure were recorded among patients treated with DX whereas no cases occurred in the IDA group. The results of this study indicate that, although DX remains the best single agent available in the treatment of breast cancer, IDA may have a role in selected patients with this disease.

Combination versus sequential single agent chemotherapy in advanced breast cancer: associations with metastatic sites and long-term survival. The Western Cancer Study Group and The Southeastern Cancer Study Group

Two hundred and twenty-two patients with advanced breast cancer were randomised in two separate trials of similar design to either concomitant combination treatment or sequential use of the same drugs given as single agents changed only at disease progression. Both trials used cyclophosphamide, methotrexate, 5-fluorouracil and prednisone; the WCSG using triiodothyronine and the SECSG using vincristine as the remaining agent. A common data base was generated for these trials and combined for analysis. Considering all patients, combination treatment was associated with a significantly increased response (46 versus 25%, P less than 0.05) but not survival improvement. For the 141 patients without liver involvement, survival was closely comparable in both treatment arms. Combination therapy did result in significant survival benefit for patients with liver involvement (P less than 0.05). These studies demonstrate: (1) in the majority of breast cancer patients, sequential single agent therapy can result in survival comparable to combination treatment; and (2) sole consideration of response frequency does not represent the optimal criterion to compare therapeutic approaches in advanced breast cancer.

A design for phase II testing of anticancer agents within a phase III clinical trial

A design for testing new anticancer agents is proposed such that the initial testing of new agents (phase II trials) is included within the framework of a comparative clinical trial (phase III). Randomization between phase II trials and the treatment groups of the phase III trial enforces consistency of patient selection and evaluation of response criteria. Patients who progress on the phase II trials of the new agents are randomized to one of the treatments of the phase III trial. Design issues, such as sample size and power, and analysis of the proposed design, are discussed. Advantages and disadvantages of the design are illustrated by sample size calculations for a current clinical trial in advanced breast cancer.