Designed Extension of Survival Studies: Application to Clinical Trials with Unrecognized Heterogeneity

It is well known that unrecognized heterogeneity among patients, such as is conferred by genetic subtype, can undermine the power of randomized trial, designed under the assumption of homogeneity, to detect a truly beneficial treatment. We consider the conditional power approach to allow for recovery of power under unexplained heterogeneity. While Proschan and Hunsberger (1995) confined the application of conditional power design to normally distributed observations, we consider more general and difficult settings in which the data are in the framework of continuous time and are subject to censoring. In particular, we derive a procedure appropriate for the analysis of the weighted log rank test under the assumption of a proportional hazards frailty model. The proposed method is illustrated through application to a brain tumor trial.

10-year follow-up of a prospective randomized trial comparing bare-metal stenting with internal mammary artery grafting for proximal, isolated de novo left anterior coronary artery stenosis the SIMA (Stenting versus Internal Mammary Artery grafting) trial

OBJECTIVES: This study was designed to compare the long-term clinical outcome of coronary artery bypass grafting (CABG) with intracoronary stenting of patients with isolated proximal left anterior descending coronary artery. BACKGROUND: Although numerous trials have compared coronary angioplasty with bypass surgery, none assessed the clinical evaluation in the long term. METHODS: We evaluated the 10-year clinical outcome in the SIMA (Stent versus Internal Mammary Artery grafting) trial. Patients were randomly assigned to stent implantation versus CABG. RESULTS: Of 123 randomized patients, 59 underwent CABG and 62 received a stent (2 patients were excluded). Follow-up after 10 years was obtained for 98% of the randomized patients. Twenty-six patients (42%) in the percutaneous coronary intervention group and 10 patients (17%) in the CABG group reached an end point (p < 0.001). This difference was due to a higher need for additional revascularization. The incidences of death and myocardial infarction were identical at 10%. Progression of the disease requiring additional revascularization was rare (5%) and was similar for the 2 groups. Stent thrombosis occurred in 2 patients (3%). Angina functional class showed no significant differences between the 2 groups. CONCLUSIONS: Both stent implantation and CABG are safe and highly effective in relieving symptoms in patients with isolated, proximal left anterior descending coronary artery stenosis. Stenting with bare-metal stents is associated with a higher need for repeat interventions. The long-term prognosis for these patients is excellent with either mode of revascularization.

Adding cetuximab to capecitabine plus oxaliplatin (XELOX) in first-line treatment of metastatic colorectal cancer: a randomized phase II trial of the Swiss Group for Clinical Cancer Research SAKK

BACKGROUND: To determine the activity and tolerability of adding cetuximab to the oxaliplatin and capecitabine (XELOX) combination in first-line treatment of metastatic colorectal cancer (MCC). PATIENTS AND METHODS: In a multicenter two-arm phase II trial, patients were randomized to receive oxaliplatin 130 mg/m(2) on day 1 and capecitabine 1000 mg/m(2) twice daily on days 1-14 every 3 weeks alone or in combination with standard dose cetuximab. Treatment was limited to a maximum of six cycles. RESULTS: Seventy-four patients with good performance status entered the trial. Objective partial response rates after external review and radiological confirmation were 14% and 41% in the XELOX and in the XELOX + Cetuximab arm, respectively. Stable disease has been observed in 62% and 35% of the patients, with 76% disease control in both arms. Cetuximab led to skin rash in 65% of the patients. The median overall survival was 16.5 months for arm A and 20.5 months for arm B. The median time to progression was 5.8 months for arm A and 7.2 months for arm B. CONCLUSION: Differences in response rates between the treatment arms indicate that cetuximab may improve outcome with XELOX. The correct place of the cetuximab, oxaliplatin and fluoropyrimidine combinations in first-line treatment of MCC has to be assessed in phase III trials.

Is adjuvant chemotherapy of benefit for postmenopausal women who receive endocrine treatment for highly endocrine-responsive, node-positive breast cancer? International Breast Cancer Study Group Trials VII and 12-93

To compare the efficacy of chemoendocrine treatment with that of endocrine treatment (ET) alone for postmenopausal women with highly endocrine responsive breast cancer. In the International Breast Cancer Study Group (IBCSG) Trials VII and 12-93, postmenopausal women with node-positive, estrogen receptor (ER)-positive or ER-negative, operable breast cancer were randomized to receive either chemotherapy or endocrine therapy or combined chemoendocrine treatment. Results were analyzed overall in the cohort of 893 patients with endocrine-responsive disease, and according to prospectively defined categories of ER, age and nodal status. STEPP analyses assessed chemotherapy effect. The median follow-up was 13 years. Adding chemotherapy reduced the relative risk of a disease-free survival event by 19% (P = 0.02) compared with ET alone. STEPP analyses showed little effect of chemotherapy for tumors with high levels of ER expression (P = 0.07), or for the cohort with one positive node (P = 0.03). Chemotherapy significantly improves disease-free survival for postmenopausal women with endocrine-responsive breast cancer, but the magnitude of the effect is substantially attenuated if ER levels are high.

Publication and non-publication of clinical trials: longitudinal study of applications submitted to a research ethics committee

BACKGROUND: Not all clinical trials are published, which may distort the evidence that is available in the literature. We studied the publication rate of a cohort of clinical trials and identified factors associated with publication and nonpublication of results. METHODS: We analysed the protocols of randomized clinical trials of drug interventions submitted to the research ethics committee of University Hospital (Inselspital) Bern, Switzerland from 1988 to 1998. We identified full articles published up to 2006 by searching the Cochrane CENTRAL database (issue 02/2006) and by contacting investigators. We analyzed factors associated with the publication of trials using descriptive statistics and logistic regression models. RESULTS: 451 study protocols and 375 corresponding articles were analyzed. 233 protocols resulted in at least one publication, a publication rate of 52%. A total of 366 (81%) trials were commercially funded, 47 (10%) had non-commercial funding. 346 trials (77%) were multi-centre studies and 272 of these (79%) were international collaborations. In the adjusted logistic regression model non-commercial funding (Odds Ratio [OR] 2.42, 95% CI 1.14-5.17), multi-centre status (OR 2.09, 95% CI 1.03-4.24), international collaboration (OR 1.87, 95% CI 0.99-3.55) and a sample size above the median of 236 participants (OR 2.04, 95% CI 1.23-3.39) were associated with full publication. CONCLUSIONS: In this cohort of applications to an ethics committee in Switzerland, only about half of clinical drug trials were published. Large multi-centre trials with non-commercial funding were more likely to be published than other trials, but most trials were funded by industry.

Does point of care prothrombin time measurement reduce the transfusion of fresh frozen plasma in patients undergoing major surgery? The POC-OP randomized-controlled trial

BACKGROUND: Bleeding is a frequent complication during surgery. The intraoperative administration of blood products, including packed red blood cells, platelets and fresh frozen plasma (FFP), is often live saving. Complications of blood transfusions contribute considerably to perioperative costs and blood product resources are limited. Consequently, strategies to optimize the decision to transfuse are needed. Bleeding during surgery is a dynamic process and may result in major blood loss and coagulopathy due to dilution and consumption. The indication for transfusion should be based on reliable coagulation studies. While hemoglobin levels and platelet counts are available within 15 minutes, standard coagulation studies require one hour. Therefore, the decision to administer FFP has to be made in the absence of any data. Point of care testing of prothrombin time ensures that one major parameter of coagulation is available in the operation theatre within minutes. It is fast, easy to perform, inexpensive and may enable physicians to rationally determine the need for FFP. METHODS/DESIGN: The objective of the POC-OP trial is to determine the effectiveness of point of care prothrombin time testing to reduce the administration of FFP. It is a patient and assessor blind, single center randomized controlled parallel group trial in 220 patients aged between 18 and 90 years undergoing major surgery (any type, except cardiac surgery and liver transplantation) with an estimated blood loss during surgery exceeding 20% of the calculated total blood volume or a requirement of FFP according to the judgment of the physicians in charge. Patients are randomized to usual care plus point of care prothrombin time testing or usual care alone without point of care testing. The primary outcome is the relative risk to receive any FFP perioperatively. The inclusion of 110 patients per group will yield more than 80% power to detect a clinically relevant relative risk of 0.60 to receive FFP of the experimental as compared with the control group. DISCUSSION: Point of care prothrombin time testing in the operation theatre may reduce the administration of FFP considerably, which in turn may decrease costs and complications usually associated with the administration of blood products. TRIAL REGISTRATION: NCT00656396.

Randomized, double-blind comparative trial of subunit and virosomal influenza vaccines for immunocompromised patients

BACKGROUND: To our knowledge, no study to date has compared the effects of a subunit influenza vaccine with those of a virosomal influenza vaccine on immunocompromised patients. METHODS: A prospective, double-blind, randomized study was conducted to compare the immunogenicity and reactogenicity of subunit and virosomal influenza vaccines for adult patients who had an immunosuppressive disease or who were immunocompromised as a result of treatment. RESULTS: There were 304 patients enrolled in our study: 131 with human immunodeficiency virus (HIV) infection, 47 with a chronic rheumatologic disease, 74 who underwent a renal transplant, 47 who received long-term hemodialysis, and 5 who had some other nephrologic disease. There were 151 patients who received the subunit vaccine and 153 patients who received the virosomal vaccine. A slightly higher percentage of patients from the subunit vaccine group were protected against all 3 influenza vaccine strains after being vaccinated, compared with patients from the virosomal vaccine group (41% vs. 30% of patients; P = .03). Among HIV-infected patients, the level of HIV RNA, but not the CD4 cell count, was an independent predictor of vaccine response. Among renal transplant patients, treatment with mycophenolate significantly reduced the immune response to vaccination. The 2 vaccines were comparable with regard to the frequency and severity of local and systemic reactions within 7 days after vaccination. Disease-specific scores for the activity of rheumatologic diseases did not indicate flare-ups 4-6 weeks after vaccination. CONCLUSIONS: For immunosuppressed patients, the subunit vaccine was slightly more immunogenic than the virosomal vaccine. The 2 vaccines were comparable with regard to reactogenicity. Vaccine response decreased with increasing degree of immune suppression. Among HIV-infected patients, the viral load, rather than the CD4 cell count, predicted the protective immune response to the vaccine. CLINICAL TRIALS REGISTRATION: NCT00783380 .

Better conduct of clinical trials: the control group in critical care trials

OBJECTIVE: To review trial design issues related to control groups. DESIGN: Review of the literature with specific reference to critical care trials. MAIN RESULTS AND CONCLUSIONS: Performing randomized controlled trials in the critical care setting presents specific problems: studies include patients with rapidly lethal conditions, the majority of intensive care patients suffer from syndromes rather than from well-definable diseases, the severity of such syndromes cannot be precisely assessed, and the treatment consists of interacting therapies. Interactions between physiology, pathophysiology, and therapies are at best marginally understood and may have a major impact on study design and interpretation of results. Selection of the right control group is crucial for the interpretation and clinical implementation of results. Studies comparing new interventions with current ones or different levels of current treatments have the problem of the necessity of defining "usual care." Usual care controls without any constraints typically include substantial heterogeneity. Constraints in the usual therapy may help to reduce some variation. Inclusion of unrestricted usual care groups may help to enhance safety. Practice misalignment is a novel problem in which patients receive a treatment that is the direct opposite of usual care, and occurs when fixed-dose interventions are used in situations where care is normally titrated. Practice misalignment should be considered in the design and interpretation of studies on titrated therapies.

Nutritional risk screening (NRS 2002): a new method based on an analysis of controlled clinical trials

A system for screening of nutritional risk is described. It is based on the concept that nutritional support is indicated in patients who are severely ill with increased nutritional requirements, or who are severely undernourished, or who have certain degrees of severity of disease in combination with certain degrees of undernutrition. Degrees of severity of disease and undernutrition were defined as absent, mild, moderate or severe from data sets in a selected number of randomized controlled trials (RCTs) and converted to a numeric score. After completion, the screening system was validated against all published RCTs known to us of nutritional support vs spontaneous intake to investigate whether the screening system could distinguish between trials with a positive outcome and trials with no effect on outcome.

Cohort study of trials submitted to ethics committee identified discrepant reporting of outcomes in publications

OBJECTIVES To identify factors associated with discrepant outcome reporting in randomized drug trials. STUDY DESIGN AND SETTING Cohort study of protocols submitted to a Swiss ethics committee 1988-1998: 227 protocols and amendments were compared with 333 matching articles published during 1990-2008. Discrepant reporting was defined as addition, omission, or reclassification of outcomes. RESULTS Overall, 870 of 2,966 unique outcomes were reported discrepantly (29.3%). Among protocol-defined primary outcomes, 6.9% were not reported (19 of 274), whereas 10.4% of reported outcomes (30 of 288) were not defined in the protocol. Corresponding percentages for secondary outcomes were 19.0% (284 of 1,495) and 14.1% (334 of 2,375). Discrepant reporting was more likely if P values were <0.05 compared with P ≥ 0.05 [adjusted odds ratio (aOR): 1.38; 95% confidence interval (CI): 1.07, 1.78], more likely for efficacy compared with harm outcomes (aOR: 2.99; 95% CI: 2.08, 4.30) and more likely for composite than for single outcomes (aOR: 1.48; 95% CI: 1.00, 2.20). Cardiology (aOR: 2.34; 95% CI: 1.44, 3.79) and infectious diseases (aOR: 1.77; 95% CI: 1.01, 3.13) had more discrepancies compared with all specialties combined. CONCLUSION Discrepant reporting was associated with statistical significance of results, type of outcome, and specialty area. Trial protocols should be made freely available, and the publications should describe and justify any changes made to protocol-defined outcomes.

Comparison of Newer-Generation Drug-Eluting With Bare-Metal Stents in Patients With Acute ST-Segment Elevation Myocardial Infarction: A Pooled Analysis of the EXAMINATION (clinical Evaluation of the Xience-V stent in Acute Myocardial INfArcTION) and COMFORTABLE-AMI (Comparison of Biolimus Eluted From an Erodible Stent Coating With Bare Metal Stents in Acute ST-Elevation Myocardial Infarction) Trials

OBJECTIVES This study sought to study the efficacy and safety of newer-generation drug-eluting stents (DES) compared with bare-metal stents (BMS) in an appropriately powered population of patients with ST-segment elevation myocardial infarction (STEMI). BACKGROUND Among patients with STEMI, early generation DES improved efficacy but not safety compared with BMS. Newer-generation DES, everolimus-eluting stents, and biolimus A9-eluting stents, have been shown to improve clinical outcomes compared with early generation DES. METHODS Individual patient data for 2,665 STEMI patients enrolled in 2 large-scale randomized clinical trials comparing newer-generation DES with BMS were pooled: 1,326 patients received a newer-generation DES (everolimus-eluting stent or biolimus A9-eluting stent), whereas the remaining 1,329 patients received a BMS. Random-effects models were used to assess differences between the 2 groups for the device-oriented composite endpoint of cardiac death, target-vessel reinfarction, and target-lesion revascularization and the patient-oriented composite endpoint of all-cause death, any infarction, and any revascularization at 1 year. RESULTS Newer-generation DES substantially reduce the risk of the device-oriented composite endpoint compared with BMS at 1 year (relative risk [RR]: 0.58; 95% confidence interval [CI]: 0.43 to 0.79; p = 0.0004). Similarly, the risk of the patient-oriented composite endpoint was lower with newer-generation DES than BMS (RR: 0.78; 95% CI: 0.63 to 0.96; p = 0.02). Differences in favor of newer-generation DES were driven by both a lower risk of repeat revascularization of the target lesion (RR: 0.33; 95% CI: 0.20 to 0.52; p < 0.0001) and a lower risk of target-vessel infarction (RR: 0.36; 95% CI: 0.14 to 0.92; p = 0.03). Newer-generation DES also reduced the risk of definite stent thrombosis (RR: 0.35; 95% CI: 0.16 to 0.75; p = 0.006) compared with BMS. CONCLUSIONS Among patients with STEMI, newer-generation DES improve safety and efficacy compared with BMS throughout 1 year. It remains to be determined whether the differences in favor of newer-generation DES are sustained during long-term follow-up.

Comparing Haemophilus influenzae type b conjugate vaccine schedules: a systematic review and meta-analysis of vaccine trials

BACKGROUND The optimal schedule and the need for a booster dose are unclear for Haemophilus influenzae type b (Hib) conjugate vaccines. We systematically reviewed relative effects of Hib vaccine schedules. METHODS We searched 21 databases to May 2010 or June 2012 and selected randomized controlled trials or quasi-randomized controlled trials that compared different Hib schedules (3 primary doses with no booster dose [3p+0], 3p+1 and 2p+1) or different intervals in primary schedules and between primary and booster schedules. Outcomes were clinical efficacy, nasopharyngeal carriage and immunological response. Results were combined in random-effects meta-analysis. RESULTS Twenty trials from 15 countries were included; 16 used vaccines conjugated to tetanus toxoid (polyribosylribitol phosphate conjugated to tetanus toxoid). No trials assessed clinical or carriage outcomes. Twenty trials examined immunological outcomes and found few relevant differences. Comparing polyribosylribitol phosphate conjugated to tetanus toxoid 3p+0 with 2p+0, there was no difference in seropositivity at the 1.0 μg/mL threshold by 6 months after the last primary dose (combined risk difference -0.02; 95% confidence interval: -0.10, 0.06). Only small differences were seen between schedules starting at different ages, with different intervals between primary doses, or with different intervals between primary and booster doses. Individuals receiving a booster were more likely to be seropositive than those at the same age who did not. CONCLUSIONS There is no clear evidence from trials that any 2p+1, 3p+0 or 3p+1 schedule of Hib conjugate vaccine is likely to provide better protection against Hib disease than other schedules. Until more data become available, scheduling is likely to be determined by epidemiological and programmatic considerations in individual settings.

Does single use of an autologous transfusion system in TKA reduce the need for allogenic blood?: a prospective randomized trial

BACKGROUND Mechanical autotransfusion systems for washed shed blood (WSB) were introduced to reduce the need for postoperative allogenic blood transfusions (ABTs). Although some authors have postulated decreased requirements for ABT by using autologous retransfusion devices, other trials, mostly evaluating retransfusion devices for unwashed shed blood (USB), verified a small or no benefit in reducing the need for postoperative ABT. Because of these contradictory findings it is still unclear whether autologous retransfusion systems for WSB can reduce transfusion requirements. QUESTIONS/PURPOSES We therefore asked whether one such autologous transfusion system for WSB can reduce the requirements for postoperative ABT. METHODS In a prospective, randomized, controlled study, we enrolled 151 patients undergoing TKA. In Group A (n=76 patients), the autotransfusion system was used for a total of 6 hours (intraoperatively and postoperatively) and the WSB was retransfused after processing. In Control Group B (n=75 patients), a regular drain without suction was used. We used signs of anemia and/or a hemoglobin value less than 8 g/dL as indications for transfusion. If necessary, we administered one or two units of allogenic blood. RESULTS Twenty-three patients (33%) in Group A, who received an average of 283 mL (range, 160-406 mL) of salvaged blood, needed a mean of 2.1 units of allogenic blood, compared with 23 patients (33%) in Control Group B who needed a mean of 2.1 units of allogenic blood. CONCLUSIONS We found the use of an autotransfusion system did not reduce the rate of postoperative ABTs. LEVEL OF EVIDENCE Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Adjudication-related processes are underreported and lack standardization in clinical trials of venous thromboembolism: a systematic review

OBJECTIVES Although the use of an adjudication committee (AC) for outcomes is recommended in randomized controlled trials, there are limited data on the process of adjudication. We therefore aimed to assess whether the reporting of the adjudication process in venous thromboembolism (VTE) trials meets existing quality standards and which characteristics of trials influence the use of an AC. STUDY DESIGN AND SETTING We systematically searched MEDLINE and the Cochrane Library from January 1, 2003, to June 1, 2012, for randomized controlled trials on VTE. We abstracted information about characteristics and quality of trials and reporting of adjudication processes. We used stepwise backward logistic regression model to identify trial characteristics independently associated with the use of an AC. RESULTS We included 161 trials. Of these, 68.9% (111 of 161) reported the use of an AC. Overall, 99.1% (110 of 111) of trials with an AC used independent or blinded ACs, 14.4% (16 of 111) reported how the adjudication decision was reached within the AC, and 4.5% (5 of 111) reported on whether the reliability of adjudication was assessed. In multivariate analyses, multicenter trials [odds ratio (OR), 8.6; 95% confidence interval (CI): 2.7, 27.8], use of a data safety-monitoring board (OR, 3.7; 95% CI: 1.2, 11.6), and VTE as the primary outcome (OR, 5.7; 95% CI: 1.7, 19.4) were associated with the use of an AC. Trials without random allocation concealment (OR, 0.3; 95% CI: 0.1, 0.8) and open-label trials (OR, 0.3; 95% CI: 0.1, 1.0) were less likely to report an AC. CONCLUSION Recommended processes of adjudication are underreported and lack standardization in VTE-related clinical trials. The use of an AC varies substantially by trial characteristics.

Differences in Time to Disease Progression Do Not Predict for Cancer-specific Survival in Patients Receiving Immediate or Deferred Androgen-deprivation Therapy for Prostate Cancer: Final Results of EORTC Randomized Trial 30891 with 12 Years of Follow-up

BACKGROUND Trials assessing the benefit of immediate androgen-deprivation therapy (ADT) for treating prostate cancer (PCa) have often done so based on differences in detectable prostate-specific antigen (PSA) relapse or metastatic disease rates at a specific time after randomization. OBJECTIVE Based on the long-term results of European Organization for Research and Treatment of Cancer (EORTC) trial 30891, we questioned if differences in time to progression predict for survival differences. DESIGN, SETTING, AND PARTICIPANTS EORTC trial 30891 compared immediate ADT (n=492) with orchiectomy or luteinizing hormone-releasing hormone analog with deferred ADT (n=493) initiated upon symptomatic disease progression or life-threatening complications in randomly assigned T0-4 N0-2 M0 PCa patients. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Time to first objective progression (documented metastases, ureteric obstruction, not PSA rise) and time to objective castration-resistant progressive disease were compared as well as PCa mortality and overall survival. RESULTS AND LIMITATIONS After a median of 12.8 yr, 769 of the 985 patients had died (78%), 269 of PCa (27%). For patients receiving deferred ADT, the overall treatment time was 31% of that for patients on immediate ADT. Deferred ADT was significantly worse than immediate ADT for time to first objective disease progression (p<0.0001; 10-yr progression rates 42% vs 30%). However, time to objective castration-resistant disease after deferred ADT did not differ significantly (p=0.42) from that after immediate ADT. In addition, PCa mortality did not differ significantly, except in patients with aggressive PCa resulting in death within 3-5 yr after diagnosis. Deferred ADT was inferior to immediate ADT in terms of overall survival (hazard ratio: 1.21; 95% confidence interval, 1.05-1.39; p [noninferiority]=0.72, p [difference] = 0.0085). CONCLUSIONS This study shows that if hormonal manipulation is used at different times during the disease course, differences in time to first disease progression cannot predict differences in disease-specific survival. A deferred ADT policy may substantially reduce the time on treatment, but it is not suitable for patients with rapidly progressing disease.