High-vs low-dose cytarabine combined with interferon alfa in patients with first chronic phase chronic myeloid leukemia. A prospective randomized phase III study

Automated synthesis and visualization of a chemotherapy treatment regimen network

Cytotoxic treatments for cancer remain highly toxic, expensive, and variably efficacious. Many chemotherapy regimens are never directly compared in randomized clinical trials (RCTs); as a result, the vast majority of guideline recommendations are ultimately derived from human expert opinion. We introduce an automated network meta-analytic approach to this clinical problem, with nodes representing regimens and edges direct comparison via RCT(s). A chemotherapy regimen network is visualized for the primary treatment of chronic myelogenous leukemia (CML). Node and edge color, size, and opacity are all utilized to provide additional information about the quality and strength of the depicted evidence. Historical versions of the network are also created. With this approach, we were able to compactly compare the results of 17 CML regimens involving RCTs of 9700 patients, representing the accumulation of 45 years of evidence. Our results closely parallel the recommendations issued by a professional guidelines organization, the National Comprehensive Cancer Network (NCCN). This approach offers a novel method for interpreting complex clinical data, with potential implications for future objective guideline development.

Survival of patients with chronic myelocytic leukemia: comparisons of estimates from clinical trial settings and population-based cancer registries

INTRODUCTION

The survival of patients with chronic myelocytic leukemia (CML) has improved during the past decades. However, there have been discrepancies between results reported from clinical trials and population-based studies. We aimed to elucidate the extent of these discrepancies.

METHODS

We examined the 5-year survival rate of patients in clinical trials of CML treatment and compared these results with the survival of patients in the general population using the Surveillance, Epidemiology, and End Results (SEER) database, correcting for differences in the age structure of the patient populations.

RESULTS

Twenty-nine trials were identified for data extraction. The survival rate calculated from SEER data was lower than the survival rate in clinical trials in the corresponding period, with differences of 2.1%-50.7%. Age-adapted survival was similar for four trials, but differences up to 35.8% were seen in most. Limitations of the study include the lack of information on chemotherapy in the SEER database and possible heterogeneity of cases.

DISCUSSION

The survival rate in clinical trials of CML treatment is higher than the survival rate of all patients with CML. We speculate that the difference may be a result of access to better medications, selection of healthier patients for trials, and the time necessary for adoption of new treatments. This finding underscores the need for population-based studies to give a more realistic idea of survival for patients with a given malignancy in the general population.

Availability of experimental therapy outside oncology randomized clinical trials in the United States

PURPOSE

Investigational cancer therapies may be available outside trials as "off-protocol therapy" (OPRx), with implications for patient safety, trial accrual, and access to care. We conducted a literature-based analysis of recent randomized trials to evaluate the potential scope and impact of OPRx in the United States.

METHODS

A MEDLINE search identified all English-language phase III medical oncology randomized clinical trials (RCTs) published over a 2-year period ending April 17, 2008. Determination of OPRx availability was based on US Food and Drug Administration approval for any indication. We limited assessment of accrual to studies with US sites. Data from articles were extracted independently by two investigators.

RESULTS

Among 172 eligible RCTs, the majority (108; 63%) evaluated drugs that were available OPRx in the United States at trial initiation, while an additional 19 (11%) evaluated interventions that became available during the trial. Among trials with US sites, time to accrual was slower (41 vs 22 months; P = .002) and less efficient (8.8 v 22.7 patients per month; P = .001) when OPRx was available. Sixty-six percent of RCTs reported at least one increased grade 3 to 4 toxicity in the experimental arm, 47% reported superior efficacy for at least one major clinical outcome in the experimental arm, and 27% reported improvement in overall survival. These outcomes did not vary on the basis of OPRx availability.

CONCLUSION

The majority of recent oncology RCTs involve experimental interventions that are available outside trials in the United States with potential impact on trial accrual. The safety and efficacy of novel interventions must be determined by clinical trials.

Ethics of mandatory research biopsy for correlative end points within clinical trials in oncology

Clinical investigators in oncology are increasingly interested in using molecular analysis of cancer tissue to understand the biologic bases of response or resistance to novel interventions and to develop prognostic and predictive biomarkers that will guide clinical decision making. Some scientific questions of this nature can only be addressed, or may best be addressed, through the conduct of a clinical trial in which research biopsies are obtained from all participants. However, trial designs with mandatory research biopsies have raised ethical concerns related to the risk of harm to participants, the adequacy of voluntary informed consent, and the potential for misunderstanding among research participants when access to an experimental intervention is linked to the requirement to undergo a research biopsy. In consideration of the ethical and scientific issues at stake in this debate, the Cancer and Leukemia Group B Ethics Committee proposes guidelines for clinical trials involving mandatory research biopsies. Any cancer clinical trial that requires research biopsies of participants must be well designed to address the scientific question, obtain the biopsy in a way that minimizes risk, and ensure that research participants are fully informed of the risks, rationale, and requirements of the study, as well as of treatment alternatives. Further guidelines and discussions of this issue are specified in this position paper. We feel that if these principles are respected, an informed adult with cancer can both understand and voluntarily consent to participation in a clinical trial involving mandatory research biopsy for scientific end points.

Dose-finding study of imatinib in combination with intravenous cytarabine: feasibility in newly diagnosed patients with chronic myeloid leukemia

The HOVON cooperative study group performed a feasibility study of escalated imatinib and intravenous cytarabine in 165 patients with early chronic-phase chronic myeloid leukemia (CML). Patients received 2 cycles of intravenous cytarabine (200 mg/m(2) or 1000 mg/m(2) days 1-7) in conjunction with imatinib (200 mg, 400 mg, 600 mg, or 800 mg), according to predefined, successive dose levels. All dose levels proved feasible. Seven dose-limiting toxicities (DLTs) were observed in 302 cycles of chemotherapy, which were caused by streptococcal bacteremia in 5 cases. Intermediate-dose cytarabine (1000 mg/m(2)) prolonged time to neutrophil recovery and platelet recovery compared with a standard dose (200 mg/m(2)). High-dose imatinib (600 mg or 800 mg) extended the time to platelet recovery compared with a standard dose (400 mg). More infectious complications common toxicity criteria (CTC) grade 3 or 4 were observed after intermediate-dose cytarabine compared with a standard-dose of cytarabine. Early response data after combination therapy included a complete cytogenetic response in 48% and a major molecular response in 30% of patients, which increased to 46% major molecular responses at 1 year, including 13% complete molecular responses. We conclude that combination therapy of escalating dosages of imatinib and cytarabine is feasible. This study was registered at www.kankerbestrijding.nl as no. CKTO-2001-03.