Reporting and interpreting adjuvant therapy clinical trials. International Breast Cancer Study Group (formerly Ludwig Group).

Identifying effective adjuvant treatments for patients with node-negative breast cancer is made difficult by the heterogeneity of the disease, the relatively low event rate and long follow-up time required, and the small magnitude of effects of current therapies. Several aspects of clinical trials that influence the appropriate reporting and interpretation of statistical results are discussed. We point out that the P value is a measure of the statistical uncertainty of an observed outcome and depends on the number of events available for analysis; it is not a measure of the magnitude of a treatment effect. We recommend that the relative reduction in the risk of an event and its 95% confidence interval be presented as an estimate of the treatment effect size, and that absolute improvements be used to judge whether treatment benefits outweigh the costs for the patient population. We suggest that subgroup analyses are important to define treatment effects within groups with different prognoses, and should be used with the understanding that multiple comparisons increase the chance of a false-positive result. Subgroup analysis should rely on the estimates of relative treatment effect and should avoid the use of the P value to declare incorrectly that "treatment is effective for one subgroup but not for another." We present the meta-analysis (overview) as a powerful method to demonstrate the statistical significance of a modest treatment effect by increasing the number of events available for analysis. The interpretation of overviews should consider the potential for treatment interactions and the validity of indirect comparisons that are not protected by a randomized design.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparative clinical trials

The therapeutic advantages of a newly developed cancer chemotherapy should be evaluated in comparison with the standard (or control) treatment. Therefore the comparative clinical trials should be designed so that the only differences observed among treatment groups are directly made by treatment program. This requires comparability of patients throughout the trial. The preferred method of evaluation is randomized controlled trials which can eliminate conscious or unconscious bias in assigning treatment. Before patients are randomized into the treatments of the trial, it is advisable to stratify patients according to known prognostic factors (stratified randomization) in an attempt to achieve equal distribution of these factors within each stratum. There are many difficulties with historical control study in the conduct of the comparative clinical trials, and its use may be acceptable only when randomized controlled trials are not feasible. The method of administration of anticancer drugs, patient eligibility, response parameters, toxicity of anticancer drugs, size and duration of the study, and advantages and disadvantages of multi-institution trials were also discussed within the framework of the comparative clinical trials.     

Globalization of clinical trials

Based on reviews of the Japanese clinical trial situation in lung cancer, gastric cancer, prostate cancer and breast cancer, it was clear that much progress has been made in short time. There are considerable differences between Japan and the West and also differences between clinical areas in Japan. For regulatory purposes bridging studies have become increasingly important. Use of identical protocols are required for effective bridging. Participations in global phase III trials is the best way of achieving registration in Japan. For successful global trials in Japan it is important to include Japanese investigators in the preparation of the protocol and to recognise the challenges facing such a project. Clinical practice in diagnosis and treatment have many differences, thus it is recommended to have clear and detailed information in the protocol. Hard end points like survival are important since they are not biased by cultural differences. There are clear difficulties with HE or QOL outcomes. The emergence of focus on evidence based medicine is also happening in Japan and will help to harmonize documentation across the world. For large adjuvant or prevention cancer global trials are essential. To facilitate global studies further development of infrastructure is necessary in Japan. Use of electronic data capture web based communication etc. will help overcome communication difficulties. Other improvements that will make Japanese participation in global trials easier and better include establishment of clinical trial centre at each hospital, introduction of trial coordinators or study nurses and an improved collaboration with company staff. A critical issue that also need addressing is agreement of centre target recruitment. We need to introduce a new flexible system in Japan if participation in global trial is to be optimised. If we can address these issues Japanese investigators and collaborative groups should be able to initiate and lead global trials in the future.     

Preclinical trials from the standpoint of clinical trials]

The establishment of reliable preclinical test is essential for the reasonable clinical trial. As a methodology for the screening of new active anticancer agents, disease oriented strategy using human tumor cell lines has been proposed in USA. The important questions in DOS are to determine the representative cell lines of specific cancer and it is also extremely important to decide the numbers of cell lines used for the screening. CPT-11, topoisomerase I inhibitor, developed in my country has been demonstrated to be active against lung cancer cell lines compared with mice tumors such as S-180 and P-388. However, no compound is demonstrated to be clinically active so far by this methodology. The criteria for the application of clinical trial are obscure and each drug company decides empirically by themselves. We have proposed to use PEI (predictive efficacy index) for the prediction of antitumor activity of new compounds. The clinical effect of new platinum analogue well correlated with this value. We have conducted phase II trial of 5-FU + LV against NSCLC without no prior chemotherapy. No responder was observed in the trial. Augmentive effect of leucovorin on the cytotoxicity of 5-FU and FdUrd was examined in vitro against NSCLC and colon cancer cell lines. Leucovorin stimulated the cytotoxicity of both drugs only against colon cancer cell lines. We tried to predict the response rate of new platinum derivative based on the data of bioassay of patient's serum administrated with platinum compounds. The predicted response rates of 254-S were 57-67% and 16-27% against SCLC and NSCLC, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Statistics in clinical trials

Statistical developments over the past several years are described in this review. Efforts in phase I studies have focused on efficient estimation of maximum tolerated dose. Issues investigated for phase II trials include incorporation of multiple endpoints and randomization. For phase III trials, methods to reduce time or use the sample size more efficiently have been investigated. However, design innovations come with costs, including possible increased risk of incorrect conclusions. Other recent challenging statistical developments in clinical trials relate to use of complementary outcomes such as quality of life and to associated biologic questions, including the emergence of the field of genomics.     

Statistics in clinical trials

Statistical developments over the past several years are described in this review. Efforts in phase I studies have focused on efficient estimation of maximum tolerated dose. Issues investigated for phase II trials include incorporation of multiple endpoints and randomization. For phase III trials, methods to reduce time or use the sample size more efficiently have been investigated. However, design innovations come with costs, including possible increased risk of incorrect conclusions. Other recent challenging statistical developments in clinical trials relate to use of complementary outcomes such as quality of life and to associated biologic questions, including the emergence of the field of genomics.     

Cancer prevention clinical trials

If external factors other than tobacco (e.g., diet, sunlight) are responsible in a major way for some cancers, then appropriate manipulation and alteration of such factors should decrease the rate of these cancers. Clinical trials in cancer prevention are an attempt to test this approach. Prevention trials are based on knowledge gained from the laboratory and from epidemiology, and they are the only way to conclusively demonstrate the effectiveness of a given prevention intervention in humans. This article discusses the development of prevention trials and specific current and future trials.     

Recent clinical trials summary

The current standard of care for the treatment of anal cancer as demonstrated by all of the completed phase 3 clinical trials remains 5-FU and mitomycin C in combination with radiation therapy. The basic elements of the approach outlined by Nigro have not changed in the last 30 years. Future phase 3 trials will serve to further perfect this approach and outline the role of HPV and dysplasia in the development and progression of this disease.     

Early stopping of clinical trials

Early stopping of clinical trials in favour of a new treatment creates ethical and scientific difficulties, which are different from those associated with early stopping due to toxicity or futility. Two major breast cancer trials have recently taken such a decision, and the problem is relevant for several ongoing trials. Here we argue that such a decision should be taken with the utmost gravity and should be based on a clear overall clinical benefit for the new treatment, and not as an automatic response to crossing a predefined threshold. Predefined rules can be used to trigger a debate within the Independent Data Monitoring and Safety Committee (IDMC) about early stopping, but the IDMC should retain the responsibility of assessing overall clinical benefit in making its recommendation.