PD-L1 Checkpoint Inhibition Narrows the Antigen-Specific T Cell Receptor Repertoire in Chronic Lymphocytic Choriomeningitis Virus Infection.

Checkpoint inhibitors are effective in restoring exhausted CD8+ T cell responses in persistent viral infections or tumors. Several compounds are in clinical use for different malignancies, but trials in patients with chronic viral infections have also been conducted. In a mouse model of persistent lymphocytic choriomeningitis virus (LCMV) infection, it was shown that checkpoint inhibitor treatment increased T cell proliferation and functionality, but its influence on the antigen-specific T cell receptor (TCR) repertoire is unknown. NP396-specific CD8+ T cells dominate during acute LCMV infection and are predominantly exhausted during chronic infection. Next-generation sequencing of NP396-specific TCRs showed that exhaustion corresponds with a significantly reduced NP396-specific TCR repertoire diversity: Shannon indices of 4 in immunized mice to 2.6 in persistently infected mice. Anti-PD-L1 treatment during persistent LCMV infection restored NP396-specific T cell responses and reduced viral titers. Nevertheless, anti-PD-L1-treated mice showed an even more narrowed TCR repertoire, with reduced TCR diversity compared to that of persistently infected control mice (Shannon indices of 2.1 and 2.6, respectively). Interestingly, anti-PD-L1 treatment-induced narrowing of the TCR repertoire negatively correlates with functional and physical restoration of the antigen-specific T cell response. Further, we found that private, hyperexpanded TCR clonotypes dominated the T cell response after anti-PD-L1 treatment. Although being private, these top clonotypes from anti-PD-L1-treated mice revealed a more closely related CDR3 motif than those of top clonotypes from persistently infected control mice. In conclusion, although targeting the PD-1/PD-L1 pathway reinvigorates exhausted CD8+ T cells, it fails to restore T cell repertoire diversity.IMPORTANCE Checkpoint inhibitors are effective immunotherapeutics to restore cancer- and virus-induced exhausted CD8+ T cells, by enhancing the quality and survival of immune responses. Although checkpoint inhibitors are already used as therapy against various cancers, not much is known about their multifaceted impact on the exhausted CD8+ T cell receptor (TCR) repertoire. This report describes for the first time the evolvement of an exhausted antigen-specific CD8+ TCR repertoire under checkpoint inhibitor treatment. By using a well-established virus model, we were able to show major shifts toward oligoclonality of the CD8+ TCR repertoire response against a massively exhausted lymphocytic choriomeningitis virus (LCMV) epitope. While supporting viral control in the LCMV model, oligoclonality and more private of TCR repertoires may impact future pathogenic challenges and may promote viral escape. Our results may explain the ongoing problems of viral escapes, unpredictable autoimmunity, and heterogeneous responses appearing as adverse effects of checkpoint inhibitor treatments.

Taxanes for adjuvant treatment of early breast cancer.

BACKGROUND: Adjuvant chemotherapy improves survival in pre- and post-menopausal women with early breast cancer. Taxanes are highly active chemotherapy agents in metastatic breast cancer. Their role in early breast cancer was examined in this review. OBJECTIVES: To review the randomised evidence comparing taxane containing chemotherapy regimens with non-taxane containing chemotherapy regimens as adjuvant treatment of pre- or post-menopausal women with early breast cancer. SEARCH STRATEGY: The Cochrane Breast Cancer Group Specialised Register was searched on 9th January 2007 using the codes for 'early breast cancer' and keywords for taxanes. Details of the search strategy used to create the register are described in the Group's module in The Cochrane Library. The reference lists of other related literature reviews and articles were also searched. SELECTION CRITERIA: Randomised trials comparing taxane containing regimens with non-taxane containing regimens in women with operable breast cancer. Women receiving neoadjuvant chemotherapy were excluded. DATA COLLECTION AND ANALYSIS: Data were collected from published trials and abstracts. Studies were assessed for eligibility and quality and the data extracted independently by two review authors. Hazard ratios (HR) were derived for time-to-event outcomes, and meta-analysis was performed using a fixed-effect model. The primary outcome measure was overall survival (OS); disease-free survival (DFS) was a secondary outcome measure. Toxicity and quality of life data were extracted when reported. MAIN RESULTS: We identified 20 studies, 12 of these (7 full publications, 5 abstracts) had sufficient data published for inclusion (11 for OS and 11 for DFS) in the review. The weighted average median follow up was 60.4 months. All studies fulfilled quality criteria either adequately or well. Amongst 18,304 women with 2483 deaths, the HR for OS was 0.81 (95% CI 0.75 to 0.88, P < 0.00001) favouring taxane containing regimens. Amongst 19,943 women with 4800 events, the HR for DFS was 0.81 (95% CI 0.77 to 0.86, P < 0.00001) favouring taxane containing regimens. There was no statistical heterogeneity for either OS or DFS. AUTHORS' CONCLUSIONS: This meta-analysis of studies supports the use of taxane containing adjuvant chemotherapy regimens with improvement of overall survival and disease-free survival for women with operable early breast cancer. The review did not identify a subgroup of patients where taxane containing treatment may have been more or less effective. Dosage and scheduling of the taxane drug is not clearly defined and we await results of the next generation of studies to determine the optimal use of taxanes in early breast cancer.

Addition of drug/s to a chemotherapy regimen for metastatic breast cancer.

BACKGROUND: The addition of a chemotherapy drug or drugs to an established regimen is one method used to increase the dose and intensity of treatment for metastatic breast cancer. OBJECTIVES: To identify and review the randomised trial evidence in the first line management of women with metastatic breast cancer that evaluates the addition of one or more chemotherapy drugs to an established regimen. SEARCH STRATEGY: We searched the specialised register maintained by the Editorial Base of the Cochrane Breast Cancer Group on 3rd August 2004 (updated search on 2nd August 2005) using the codes for "advanced breast cancer" and "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 that evaluated a first line regimen of at least two chemotherapy drugs, and compared it to that same regimen plus the addition of one or more chemotherapy drugs in women with metastatic breast cancer. DATA COLLECTION AND ANALYSIS: We collected data from published trials and assessed studies for eligibility and quality. Two reviewers extracted data independently. We derived hazard ratios (HR) from time-to-event outcomes where possible, and a fixed effect model was used for meta-analysis. We analysed response rates as dichotomous variables and extracted toxicity data where available. MAIN RESULTS: We identified 17 trials reporting on 22 treatment comparisons (2674 patients randomised). Fifteen trials (20 treatment comparisons) reported results for tumour response and 11 trials (14 treatment comparisons) published time-to-event data for overall survival. There were 1532 deaths in 2116 women randomised to trials of the addition of a drug to the regimen and control (the regimen alone). There was no detectable difference in overall survival between these patients, with an overall HR of 0.96 (95% CI 0.87 to 1.07, P = 0.47) and no statistically significant heterogeneity. We found no difference in time to progression between these regimens, with an overall HR of 0.93 (95% CI 0.81 to 1.07, P = 0.31) and no statistically significant heterogeneity. Addition of a drug to the regimen was favourably associated with overall tumour response rates (OR 1.21, 95% CI 1.01 to 1.44, P = 0.04) although we observed statistically significant heterogeneity for this outcome across the trials. Where measured, acute toxicities such as alopecia, nausea and vomiting and leukopenia were more common with the addition of a drug. AUTHORS' CONCLUSIONS: The addition of one or more drugs to the regimen shows a statistically significant advantage for tumour response in women with metastatic breast cancer but the results suggest no difference in survival time or time to progression. The positive effect on tumour response observed with addition of a drug to the regimen was also associated with increased toxicity.

Taxane containing regimens for metastatic breast cancer.

BACKGROUND: It is generally accepted that taxanes are among the most active chemotherapy agents in the management of metastatic breast cancer. OBJECTIVES: To identify and review the randomised evidence comparing taxane containing chemotherapy regimens with regimens not containing a taxane 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", "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 taxane-containing chemotherapy regimens with regimens not containing taxanes 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: Twenty one eligible trials were identified of which 12 have published time-to-event data and 16 have reported response data. The quality of randomisation was generally not described. An estimated 2621 deaths in 3643 randomised women demonstrate a statistically significant difference in favour of taxane-containing regimens with a HR for overall survival of 0.93 (95% CI=0.86-1.00, p=0.05) and no statistically significant heterogeneity. If the analysis is restricted to trials of firstline chemotherapy the HR changes to 0.92 and is no longer statistically significant (95% CI 0.84-1.02, p=0.11). There was also a significant difference in favour of taxanes in relation to time to progression (overall HR 0.92, 95%CI 0.85-0.99, p=0.02) and overall response in assessable women (overall OR 1.34, 95%CI 1.18-1.52, p<0.00001) however there was strong statistical evidence of heterogeneity (P<0.00001), probably reflecting the varying efficacy of the comparator regimens used in the trials. AUTHORS' CONCLUSIONS: When all trials are considered, taxane-containing regimens appear to improve overall survival, time to progression and overall response in women with metastatic breast cancer. The degree of heterogeneity encountered indicates that taxane-containing regimens are more effective than some, but not all non-taxane-containing regimens.

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.

Systematic reviews of chemotherapy and endocrine therapy in metastatic breast cancer.

Metastatic breast cancer is incurable but often responsive to treatment. There is little evidence-based consenus on when to use which treatments, in what combination and for how long. Systematic reviews were performed on 12 prospectively defined, clinically relevant research questions to support the development of evidence-based clinical practice guidelines. A comprehensive search of Medline from 1966 to 1996 identified over 1800 controlled trials. Eligibility and data extraction were performed independently by two blinded reviewers. Trial results were summarised by ratios of median survivals (RMS) and P -values for survival curve comparisons with meta-analysis by weighted combination of these statistics. Sixty-five publications reporting 97 treatment comparisons were included. There was moderate evidence that more rather than fewer cycles of chemotherapy improved survival (RMS:1.23, P -0.01). The evidence did not support: higher rather than lower doses of chemotherapy (or of endocrine therapy); any one class of endocrine agent over all others; multiple endocrine agents over a single agent; or, combined chemotherapy and endocrine therapy over either single modality. Only six trials assessed quality of life revealing better quality of life with more rather than fewer cycles of chemotherapy and with standard rather than lower doses of chemotherapy. These systematic reviews reveal counterintuitive evidence useful to everyday practice, in particular that more rather than fewer cycles of chemotherapy lead to better quality of life and longer survival.

Chemotherapy alone versus endocrine therapy alone for metastatic breast cancer.

BACKGROUND: Both chemotherapy and endocrine therapy can be used as treatments for metastatic breast cancer. OBJECTIVES: To review the evidence and determine whether chemotherapy or endocrine therapy has the most beneficial effect on treatment outcomes (survival, response rate, toxicity and quality of life). SEARCH STRATEGY: The specialised register maintained by the Editorial Base of the Cochrane Breast Cancer Group was searched on 16th September 2002 using the codes for "advanced breast cancer", "chemotherapy" and "endocrine therapy". 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 the effects of chemotherapy alone with endocrine therapy alone on pre-specified endpoints in metastatic breast cancer. DATA COLLECTION AND ANALYSIS: Data were collected from published trials. Hazard ratios were derived for survival analysis 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: The primary analysis of overall effect using hazard ratios derived from published survival curves involved six trials (692 women). There was no significant difference seen (HR=0.94, 95%CI 0.79-1.12, p=0.5). A test for heterogeneity was p=0.1. A pooled estimate of reported response rates in eight trials involving 817 women shows a significant advantage for chemotherapy over endocrine therapy with RR=1.25 (1.01-1.54, p=0.04). However the two largest trials showed trends in opposite directions, and a test for heterogeneity was p=0.0018. There was little information available on toxicity and quality of life. Six of the seven fully published trials commented on increased toxicity with chemotherapy, mentioning nausea, vomiting and alopecia. Three of the seven mentioned aspects of quality of life, with differing results. Only one trial formally measured quality of life, concluding that it was better with chemotherapy. REVIEWER'S CONCLUSIONS: In women with metastatic breast cancer and where hormone receptors are present, a policy of treating first with endocrine therapy rather than chemotherapy is recommended except in the presence of rapidly progressive disease.

Platinum containing regimens for metastatic breast cancer.

BACKGROUND: Studies have reported high tumour response rates for platinum-containing regimens in the treatment of women with metastatic breast cancer. OBJECTIVES: To identify and review the evidence from randomised trials comparing platinum-containing chemotherapy regimens with regimens not containing platinum 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", "chemotherapy". Details of the search strategy applied to create the register, and the procedure used to code references, are described in the Cochrane Breast Cancer Group module on The Cochrane Library. SELECTION CRITERIA: Randomised trials comparing platinum-containing chemotherapy regimens with regimens not containing platinum in women with metastatic breast cancer. DATA COLLECTION AND ANALYSIS: Studies were assessed for eligibility and quality, and data (from published trials) 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 (not available) were extracted where present. MAIN RESULTS: Thirteen eligible trials were identified, of which 12 had published time-to-event data. The quality of randomisation was generally not described.Data, based on an estimated 987 deaths in 1377 women, was unable to show a statistically significant difference in favour of platinum-containing regimens. The hazard ratio (HR) for overall survival was 1.00 (95% confidence interval (CI) 0.88 to 1.15, p=0.96), with minor heterogeneity. Results were similar when the analysis was limited to trials in women receiving first line chemotherapy. There was no statistically significant difference in favour of platinum-containing regimens for time to progression (overall HR of 1.06 (95% CI 0.95 to 1.19, p=0.31) although there was marked evidence of heterogeneity (p< 0.0001). There was a statistically significant difference in overall response in favour of platinum-containing regimens (OR 1.47; 95% CI 1.23 to 1.76, p=0.0001). However, there was strong statistical evidence of heterogeneity (p < 0.00010) probably reflecting the varying efficacy of the comparator regimens used in the trials. Heterogeneity may also reflect the differences, and difficulties, in assessing response. Women receiving platinum-containing regimens experienced statistically significant greater toxicity levels for leukopenia, hair loss, nausea and vomiting and anaemia compared with those receiving non-platinum regimens. REVIEWERS' CONCLUSIONS: In view of the significant excess toxicity, lack of progression or survival benefit and the availability of less toxic active agents it is difficult to justify the use of platinum-containing regimens, particularly as first line treatment for women with metastatic breast cancer in routine clinical practice. Ongoing trials are examining the possibility of synergy between platins and trastuzamab, a monoclonal antibody treatment. No randomised trials containing oxalplatin were identified for the present review.

Platinum containing regimens for metastatic breast cancer.

BACKGROUND: Studies have reported high tumour response rates for platinum-containing regimens in the treatment of women with metastatic breast cancer. OBJECTIVES: To identify and review the evidence from randomised trials comparing platinum-containing chemotherapy regimens with regimens not containing platinum 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", "chemotherapy". Details of the search strategy applied to create the register, and the procedure used to code references, are described in the Cochrane Breast Cancer Group module on The Cochrane Library. SELECTION CRITERIA: Randomised trials comparing platinum-containing chemotherapy regimens with regimens not containing platinum in women with metastatic breast cancer. DATA COLLECTION AND ANALYSIS: Studies were assessed for eligibility and quality, and data (from published trials) 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 (not available) were extracted where present. MAIN RESULTS: Thirteen eligible trials were identified, of which 12 had published time-to-event data. The quality of randomisation was generally not described.Data, based on an estimated 987 deaths in 1377 women, was unable to show a statistically significant difference in favour of platinum-containing regimens. The hazard ratio (HR) for overall survival was 1.00 (95% confidence interval (CI) 0.88 to 1.15, p=0.96), with minor heterogeneity. Results were similar when the analysis was limited to trials in women receiving first line chemotherapy. There was no statistically significant difference in favour of platinum-containing regimens for time to progression (overall HR of 1.06 (95% CI 0.95 to 1.19, p=0.31) although there was marked evidence of heterogeneity (p< 0.0001). There was a statistically significant difference in overall response in favour of platinum-containing regimens (OR 1.47; 95% CI 1.23 to 1.76, p=0.0001). However, there was strong statistical evidence of heterogeneity (p < 0.00010) probably reflecting the varying efficacy of the comparator regimens used in the trials. Heterogeneity may also reflect the differences, and difficulties, in assessing response. Women receiving platinum-containing regimens experienced statistically significant greater toxicity levels for leukopenia, hair loss, nausea and vomiting and anaemia compared with those receiving non-platinum regimens. REVIEWERS' CONCLUSIONS: In view of the significant excess toxicity, lack of progression or survival benefit and the availability of less toxic active agents it is difficult to justify the use of platinum-containing regimens, particularly as first line treatment for women with metastatic breast cancer in routine clinical practice. Ongoing trials are examining the possibility of synergy between platins and trastuzamab, a monoclonal antibody treatment. No randomised trials containing oxalplatin were identified for the present review.

Taxane containing regimens for metastatic breast cancer.

BACKGROUND: It is generally accepted that taxanes are among the most active chemotherapy agents in the management of metastatic breast cancer. OBJECTIVES: To identify and review the randomised evidence comparing taxane containing chemotherapy regimens with regimens not containing a taxane 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", "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 taxane-containing chemotherapy regimens with regimens not containing taxanes in women with metastatic breast cancer. DATA COLLECTION AND ANALYSIS: Data were collected from published trials. Studies were assessed for eligiblity 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: Twenty eligible trials were identified of which 17 had published at least some results, and 12 had published time-to-event data. The quality of randomisation was generally not described. An estimated 2659 deaths in 3643 randomised women demonstrate a statistically significant difference in favour of taxane-containing regimens with a HR for overall survival of 0.90 (95% CI=0.84-0.97, p=0.009) and no significant heterogeneity. If the analysis is restricted to trials of firstline chemotherapy the HR changes to 0.92 and is no longer statistically significant (95% CI 0.84-1.02, p=0.12). There was also a significant difference in favour of taxanes in relation to time to progression (overall HR 0.87, 95%CI 0.81-0.93, p<0.0001) and overall response (overall OR 1.29, 95%CI 1.13-1.47, p<0.0001) however there was strong statistical evidence of heterogeneity (P<0.00001), probably reflecting the varying efficacy of the comparator regimens used in the trials. REVIEWER'S CONCLUSIONS: When all trials are considered, taxane-containing regimens appear to improve overall survival, time to progression and overall response in women with metastatic breast cancer. The degree of heterogeneity encountered indicates that taxane-containing regimens are more effective than some, but not all non-taxane-containing regimens.

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 proposed protocol for the development of a register of trials of weight management of childhood overweight and obesity.

INTRODUCTION: Currently, there is no international co-ordinated approach to research into childhood obesity. This is despite much research activity in this area and the universality of the condition. METHOD: This proposal involves the development of an international register of randomized controlled trials of weight management in overweight and obese children. The primary purpose of the register will be to generate and perform important, focussed prospective meta-analysis of data from trials using the conventional weight management strategies. Prospective meta-analysis is an emerging methodology and has some methodological advantages over retrospective meta-analysis. PROPOSAL: The fundamental initial tasks will be to create scientific interest in the proposal, to identify and co-ordinate Management and Advisory Committees with international membership, to determine and define inclusion and exclusion criteria for trial registration, to define the questions that need to be addressed by prospective meta-analysis and finally to engage investigators to register.

A systematic review of taxane-containing regimens for metastatic breast cancer.

We compared the results of randomised trials comparing taxane-containing chemotherapy regimens with regimens not containing a taxane in women with metastatic breast cancer. The specialised register of the Cochrane Breast Cancer Group was searched in March 2004. Eligibility was assessed and data extracted from eligible studies by two reviewers. Hazard ratios (HR) were derived for time-to-event outcomes, and a fixed-effect model was used for meta-analysis. Tumour response rates were analysed as dichotomous variables. Of 21 eligible trials, 16 had published some results and 12 data on overall survival. An estimated 2621 deaths among 3643 women suggest a significant difference in overall survival in favour of taxane-containing regimens (HR 0.93, 95% confidence interval (CI) 0.86-1.00, P=0.05). The treatment effect on survival was similar if only trials of first-line chemotherapy were included, although not statistically significant. There appeared to be an advantage for taxanes in time to progression (HR 0.92, 95% CI 0.85-0.99, P=0.02) and overall response (odds ratio (OR) 1.34, 95% CI 1.18-1.52, P<0.001). There was significant heterogeneity across the trials (P<0.001), partly because of the varying efficacy of the comparator regimens. Taxane-containing regimens improved overall survival in women with metastatic breast cancer. Taxane-containing regimens are more effective than some, but not all, nontaxane-containing regimens.

Systematic review of taxane-containing versus non-taxane-containing regimens for adjuvant and neoadjuvant treatment of early breast cancer.

The use of taxanes in early breast cancer is increasing. However, there are few mature studies of taxanes in this setting, and their role is uncertain. Our systematic review of randomised trials of adjuvant or neoadjuvant systemic therapy identified ten reported trials comparing a taxane-containing group with a non-taxane-containing control group in women with early breast cancer. Four of five neoadjuvant trials showed higher rates of complete response with taxanes, although differences were not significant. All five adjuvant trials showed improvements in disease-free survival with taxanes, and these improvements were significant in three trials and independent of oestrogen-receptor status. Two trials showed a significant improvement in overall survival. These results support the use of adjuvant taxanes in women with early breast cancer and involved lymph nodes. Longer follow-up of these trials and results from continuing trials are needed to clarify the best use of taxanes in early breast cancer.

Randomized double-blind trial of beta-carotene and vitamin C in women with minor cervical abnormalities.

A double-blind, placebo-controlled, randomized, factorial study using a daily oral administration of 30 mg beta-carotene and/or 500 mg vitamin C was conducted in 141 women with colposcopically and histologically confirmed minor squamous atypia or cervical intra-epithelial neoplasia (CIN) I. Over approximately 2 years of follow-up, 43 lesions regressed to normal and 13 progressed to CIN II. The regression rate was slightly higher, but not significantly so, in those randomized to beta-carotene compared to no beta-carotene (hazard ratio = 1.58, 95% CI: 0.86-2.93, P = 0.14) and slightly lower, but not statistically significant, for those randomized to vitamin C compared to no vitamin C (hazard ratio = 0.65, 95% CI: 0.35-1.21, P = 0.17). In a model with no interaction, the progression rate was slightly higher in those randomized to beta-carotene (hazard ratio = 1.75, 95% CI: 0.57-5.36, P = 0.32) and also in those randomized to vitamin C (hazard ratio = 2.40, 95% CI: 0.74-7.80, P = 0.13). Neither of these were statistically significant. However, there was some evidence of an interaction effect of the two compounds on the progression rate (P = 0.052), with seven of the progressed lesions occurring in those randomized to both vitamins compared to a total of six in the three other groups. The currently available evidence from this and other trials suggests that high doses of these compounds are unlikely to increase the regression or decrease the progression of minor atypia and CIN I.