scholarly journals To randomize, or not to randomize, that is the question: using data from prior clinical trials to guide future designs

2019 ◽  
Vol 21 (10) ◽  
pp. 1239-1249
Author(s):  
Alyssa M Vanderbeek ◽  
Steffen Ventz ◽  
Rifaquat Rahman ◽  
Geoffrey Fell ◽  
Timothy F Cloughesy ◽  
...  
Keyword(s):  
Overall Survival ◽  
Clinical Trials ◽  
Phase Ii ◽  
Primary Endpoint ◽  
Effect Size ◽  
Standard Of Care ◽  
Error Rates ◽  
Phase Ii Trials ◽  
False Positive Error ◽  
Interstudy Variability

Abstract Background Understanding the value of randomization is critical in designing clinical trials. Here, we introduce a simple and interpretable quantitative method to compare randomized designs versus single-arm designs using indication-specific parameters derived from the literature. We demonstrate the approach through application to phase II trials in newly diagnosed glioblastoma (ndGBM). Methods We abstracted data from prior ndGBM trials and derived relevant parameters to compare phase II randomized controlled trials (RCTs) and single-arm designs within a quantitative framework. Parameters included in our model were (i) the variability of the primary endpoint distributions across studies, (ii) potential for incorrectly specifying the single-arm trial’s benchmark, and (iii) the hypothesized effect size. Strengths and weaknesses of RCT and single-arm designs were quantified by various metrics, including power and false positive error rates. Results We applied our method to show that RCTs should be preferred to single-arm trials for evaluating overall survival in ndGBM patients based on parameters estimated from prior trials. More generally, for a given effect size, the utility of randomization compared with single-arm designs is highly dependent on (i) interstudy variability of the outcome distributions and (ii) potential errors in selecting standard of care efficacy estimates for single-arm studies. Conclusions A quantitative framework using historical data is useful in understanding the utility of randomization in designing prospective trials. For typical phase II ndGBM trials using overall survival as the primary endpoint, randomization should be preferred over single-arm designs.

Predictive value of phase II clinical trials in pancreatic cancer: Rethinking the road to progress.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. 4036-4036 ◽  
Author(s):  
Daniel M. Halperin ◽  
J. Jack Lee ◽  
James C. Yao
Keyword(s):  
Clinical Trials ◽  
Phase Ii ◽  
Predictive Value ◽  
Error Rates ◽  
Phase Iii ◽  
Type I ◽  
Type Ii ◽  
Type Ii Error ◽  
Phase Ii Trials ◽  
Fda Approval

4036 Background: Few new therapies for pancreatic adenocarcinoma (PC) have been approved by the Food and Drug Administration (FDA) or recommended by the National Comprehensive Cancer Network (NCCN), reflecting frequent failures in phase III trials. We hypothesize that the high failure rate in large trials is due to a low predictive value for “positive” phase II studies. Methods: Given a median time from initiation of clinical trials to FDA approval of 6.3 years, we conducted a systematic search of the clinicaltrials.gov database for phase II interventional trials of antineoplastic therapy in PC initiated from 1999-2004. We reviewed drug labels and NCCN guidelines for FDA approval and guideline recommendations. Results: We identified 70 phase II trials that met our inclusion criteria. Forty-five evaluated compounds without preexisting FDA approval, 23 evaluated drugs approved in other diseases, and 2 evaluated cellular therapies. With a median follow-up of 12.5 years, none of these drugs gained FDA approval in PC. Four trials, all combining chemotherapy with radiation, eventually resulted in NCCN recommendations. Forty-two of the trials have been published. Of 16 studies providing pre-specified type I error rates, these rates were ≥0.1 in 8 studies, 0.05 in 6 studies and <0.025 in 2 studies. Of 21 studies specifying type II error rates, 7 used >0.1, 10 used 0.1, and 4 used <0.1. Published studies reported a median enrollment of 47 subjects. Fourteen trials reported utilizing a randomized design. Conclusions: The low rate of phase II trials resulting in eventual regulatory approval of therapies for PC reflects the challenge of conquering a tough disease as well as deficiencies in the statistical designs. New strategies are necessary to quantify and improve odds of success in drug development. Statistical parameters of individual or coupled phase II trials should be tailored to achieve the desired predictive value prior to initiating pivotal phase III studies. Positive predictive value of a phase II study assuming a 1%, 2%, or 5% prior probability of success and 10% type II error rate. [Table: see text]

scholarly journals Unconventional Anticancer Agents: A Systematic Review of Clinical Trials

2006 ◽  
Vol 24 (1) ◽  
pp. 136-140 ◽  
Author(s):  
Andrew J. Vickers ◽  
Joyce Kuo ◽  
Barrie R. Cassileth
Keyword(s):  
Clinical Trials ◽  
Phase I ◽  
Cancer Patients ◽  
Phase Ii ◽  
Dose Finding ◽  
Phase Iii ◽  
High Dose ◽  
Free Text ◽  
Phase Ii Trials ◽  
Off Label

Purpose A substantial number of cancer patients turn to treatments other than those recommended by mainstream oncologists in an effort to sustain tumor remission or halt the spread of cancer. These unconventional approaches include botanicals, high-dose nutritional supplementation, off-label pharmaceuticals, and animal products. The objective of this study was to review systematically the methodologies applied in clinical trials of unconventional treatments specifically for cancer. Methods MEDLINE 1966 to 2005 was searched using approximately 200 different medical subject heading terms (eg, alternative medicine) and free text words (eg, laetrile). We sought prospective clinical trials of unconventional treatments in cancer patients, excluding studies with only symptom control or nonclinical (eg, immune) end points. Trial data were extracted by two reviewers using a standardized protocol. Results We identified 14,735 articles, of which 214, describing 198 different clinical trials, were included. Twenty trials were phase I, three were phase I and II, 70 were phase II, and 105 were phase III. Approximately half of the trials investigated fungal products, 20% investigated other botanicals, 10% investigated vitamins and supplements, and 10% investigated off-label pharmaceuticals. Only eight of the phase I trials were dose-finding trials, and a mere 20% of phase II trials reported a statistical design. Of the 27 different agents tested in phase III, only one agent had a prior dose-finding trial, and only for three agents was the definitive study initiated after the publication of phase II data. Conclusion Unconventional cancer treatments have not been subject to appropriate early-phase trial development. Future research on unconventional therapies should involve dose-finding and phase II studies to determine the suitability of definitive trials.

Design Issues of Randomized Phase II Trials and a Proposal for Phase II Screening Trials

2005 ◽  
Vol 23 (28) ◽  
pp. 7199-7206 ◽  
Author(s):  
Lawrence V. Rubinstein ◽  
Edward L. Korn ◽  
Boris Freidlin ◽  
Sally Hunsberger ◽  
S. Percy Ivy ◽  
...  
Keyword(s):  
Phase Ii ◽  
False Positive ◽  
Standard Treatment ◽  
False Negative ◽  
Error Rates ◽  
Targeted Treatment ◽  
Phase Iii ◽  
Phase Ii Trials ◽  
Treatment Control ◽  
Randomized Phase Ii

Future progress in improving cancer therapy can be expedited by better prioritization of new treatments for phase III evaluation. Historically, phase II trials have been key components in the prioritization process. There has been a long-standing interest in using phase II trials with randomization against a standard-treatment control arm or an additional experimental arm to provide greater assurance than afforded by comparison to historic controls that the new agent or regimen is promising and warrants further evaluation. Relevant trial designs that have been developed and utilized include phase II selection designs, randomized phase II designs that include a reference standard-treatment control arm, and phase II/III designs. We present our own explorations into the possibilities of developing “phase II screening trials,” in which preliminary and nondefinitive randomized comparisons of experimental regimens to standard treatments are made (preferably using an intermediate end point) by carefully adjusting the false-positive error rates (α or type I error) and false-negative error rates (β or type II error), so that the targeted treatment benefit may be appropriate while the sample size remains restricted. If the ability to conduct a definitive phase III trial can be protected, and if investigators feel that by judicious choice of false-positive probability and false-negative probability and magnitude of targeted treatment effect they can appropriately balance the conflicting demands of screening out useless regimens versus reliably detecting useful ones, the phase II screening trial design may be appropriate to apply.

Evolution of statistical methodology and design of phase II/III clinical trials in non-small cell lung cancer (NSCLC)

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 7108-7108 ◽  
Author(s):  
R. K. Bagai ◽  
A. Dowlati
Keyword(s):  
Clinical Trials ◽  
Survival Time ◽  
Phase Ii ◽  
Response Rate ◽  
Phase Iii ◽  
Type I ◽  
Phase Ii Trials ◽  
Improvement In Survival ◽  
Phase Ii And Iii ◽  
Phase Iii Studies

7108 Background: A significant heterogeneity exists in the design and reporting of phase II and III therapeutic clinical trials in NSCLC. This has led to difficulty in interpretation of these trials leading to over- or underestimation of therapeutic efficacy. We set out to investigate the statistical methodology and design reporting of chemotherapeutic trials in NSCLC published in the Journal of Clinical Oncology (JCO) over 20 years. Methods: We identified all phase II and III NSCLC chemotherapy trials published in the JCO from January 1983 to August 2005. All manuscripts were reviewed to evaluate components of statistical design that were reported, including: sample size calculation, power, type I error, single or multiple drug trials, relative response sought in phase II trials and improvement in survival time or response rate sought in phase III trials. Results: One hundred forty eight trials were identified. 52% of studies were phase III and 48% were phase II. The majority (78%) were conducted in advanced stage NSCLC. Sample size calculations were reported for only 58% of phase III studies and 31% of phase II studies. Power was reported in 66% of phase III studies and 13% of phase II trials. Type I error was reported in 47% of phase III studies and 17% in phase II studies. 60% of phase III trials defined endpoints (percentage improvement in survival time, improvement in survival time in months or increase in response rate). 41% of phase II trails defined the target response rate, ranging from response rates of 15% to 70%. The frequency of adequate reporting of statistical design was shown to increase from 31% in 1990–1995 to 64% in 2000–2005 ( table ). Conclusions: Significant heterogeneity exists in trial design and reporting of phase II and III trials in NSCLC. This impacts the ability to adequately interpret these studies. More widespread application of statistical methods in planning and reporting of lung cancer clinical trials are necessary to increase reliability of data. [Table: see text] No significant financial relationships to disclose.

Statistical power of negative randomized clinical trials (RCTs) presented at the American Society of Clinical Oncology (ASCO) Annual Meetings

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 6516-6516
Author(s):  
P. Bedard ◽  
M. K. Krzyzanowska ◽  
M. Pintilie ◽  
I. F. Tannock
Keyword(s):  
Clinical Trials ◽  
Sample Size ◽  
Annual Meeting ◽  
Primary Endpoint ◽  
Effect Size ◽  
Statistical Power ◽  
Randomized Clinical Trials ◽  
Medium Effect ◽  
Post Hoc ◽  
Adequate Sample Size

6516 Background: Underpowered randomized clinical trials (RCTs) may expose participants to risks and burdens of research without scientific merit. We investigated the prevalence of underpowered RCTs presented at ASCO annual meetings. Methods: We surveyed all two-arm parallel phase III RCTs presented at the ASCO annual meeting from 1995–2003 where differences for the primary endpoint were non-statistically significant. Post hoc calculations were performed using a power of 80% and a=0.05 (two-sided) to determine the sample size required to detect a small, medium, and large effect size between the two groups. For studies reporting a proportion or time to event as a primary endpoint, effect size was expressed as an odds ratio (OR) or hazard ratio (HR) respectively, with a small effect size defined as OR/HR=1.3, medium effect size OR/HR=1.5, and large effect OR/HR=2.0. Logistic regression was used to identify factors associated with lack of statistical power. Results: Of 423 negative RCTs for which post hoc sample size calculations could be performed, 45 (10.6%), 138 (32.6%), and 333 (78.7%) had adequate sample size to detect small, medium, and large effect sizes respectively. Only 35 negative RCTs (7.1%) reported a reason for inadequate sample size. In a multivariable model, studies presented at plenary or oral sessions (p<0.0001) and multicenter studies supported by a co-operative group were more likely to have adequate sample size (p<0.0001). Conclusion: Two-thirds of negative RCTs presented at the ASCO annual meeting do not have an adequate sample to detect a medium-sized treatment effect. Most underpowered negative RCTs do not report a sample size calculation or reasons for inadequate patient accrual. No significant financial relationships to disclose.

Beyond metastatic renal cell carcinoma (mRCC) clinical trials: Targeted therapy use and overall survival in community oncology clinics.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e15061-e15061
Author(s):  
Michael Roger Harrison ◽  
Daniel J. George ◽  
Mark S. Walker ◽  
Lori L. Hudson ◽  
Connie Chen ◽  
...  
Keyword(s):  
Overall Survival ◽  
Clinical Trials ◽  
Cox Regression ◽  
Significant Risk ◽  
Standard Of Care ◽  
Community Practice ◽  
Disease Characteristics ◽  
Differential Outcomes ◽  
Drug Mechanism ◽  
Community Oncology

e15061 Background: Targeted therapies are now the standard of care for mRCC with use and expected outcomes defined by clinical trials. What are "real world" patterns of use and survival outcomes in mRCC patients (pts) treated in community oncology (COMM) settings? Methods: We reviewed a retrospective registry of adult mRCC pts from 11 COMM oncology practices, diagnosed since 1/2007 and not enrolled in a trial. Demographics, disease characteristics, treatment patterns and outcomes were recorded from the EMR and supplemented with chart abstraction.Pts were grouped by treatment sequence reflecting up to 3 exposures based on drug mechanism of action (VEGFR TKI [TKI] or mTOR inhibitor [mTOR]). Other pts received a non-TKI, non-mTOR therapy in the 1st three exposures (e.g., bevacizumab, cytokines, combinations, etc.). No Therapy pts received no systemic therapy as of data analysis. Survival analyses included Kaplan-Meier methods and Cox regression. Results: 255 patient/disease characteristics included: age 65±11 yrs; 68% male; 71% Caucasian; 62% clear cell histology (25% unknown); 1.6 ±0.9 metastatic sites. MSKCC risk was: 28% good, 63% intermediate, 10% poor. Median overall survival (OS) was 12.1 mo (95% CI: 8.7-15.4); median OS by sequence was: No Therapy (n=38; 3.7), mTOR (n=28; 5.2), TKI (n=79; 8.7), mTOR/TKI (n=10; 9.3), TKI/mTOR (n=32; 13.7), TKI/TKI (n=24; 20.7), Other (n=20; 22.5), TKI/mTOR/TKI (N=14; 29.8), TKI/TKI/mTOR (N=10; 33.1). Cox regression identified subgroups with differential outcomes. After significant covariates were controlled, compared with No Therapy, all regimens with TKI as 1st exposure had hazard ratios (HR) <1.0 (range=0.14 – 0.51; all p values ≤ 0.02). Other treatment had HR=0.31 (P=0.001), but when mTOR was the only treatment HR=1.04 (p=0.88). MSKCC scores of intermediate (HR=2.4) or poor (HR=4.5) were a significant risk (p<0.001). Conclusions: Only pts treated with two TKI exposures (≥20.7 mo) approached the best OS seen in trials (26 mo). For mTOR only, 1st line treatment in sicker patients, OS (5.2 mo) was shorter than trials (11 mo). Outcome differences between trial and community practice settings offer insights into opportunities to optimize care.

A phase II trial of trabectedin (T) in patients with hormone receptor-positive, HER2-negative advanced breast cancer, according to xeroderma pigmentosum gene (XPG) expression.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. TPS652-TPS652
Author(s):  
Ahmad Awada ◽  
Javier Cortes ◽  
Miguel Martin ◽  
Philippe Aftimos ◽  
Mafalda Oliveira ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Overall Survival ◽  
Phase Ii ◽  
Primary Endpoint ◽  
Hormone Receptor ◽  
Single Agent ◽  
Progression Free Survival ◽  
Open Label ◽  
Hormone Receptor Positive ◽  
Metastatic Setting

TPS652 Background: Hormone receptor-positive, HER2-negative breast cancer (BC) is currently associated with 3-4 years overall survival in the metastatic setting and, after ≥2 relapses, therapeutic approaches are reduced. XPG expression is frequently modified in BC. T is a cytotoxic agent that forms a complex with the XPG, inducing cell apoptosis. As a single agent, T has shown anti-tumor activity in patients with poor prognosis BC, and a better response to T in BC patients with XPG RNA overexpression has been observed. Methods: This is an open-label, phase II study of T (1.3 mg/m2 in 3-hour intravenous infusion every 3 weeks) in patients with hormone receptor-positive, HER2-negative advanced BC, according to their primary tumor’s XPG expression. Primary endpoint: to evaluate the efficacy of T in terms of progression free survival rate at 4 months (PFS4) according to the patient’s XPG expression. Secondary endpoints: Comparison of PFS, overall response rate, duration of response, overall survival and safety profile in XPG-high and XPG-low patients. Assignment: BC patients who have previously received anthracyclins and/or taxanes and who progressed after 2-5 chemotherapy lines will be assigned according to their XPG expression from paraffin embedded tumor samples to stratum A (XPG-high [>3]) or to stratum B (XPG-low [≤3]) (threshold was selected from median XPG expression values observed in a previous trial). Statistical methods: A two-stage design was chosen: at a first stage 20 patients will be enrolled in each stratum. A futility analysis (O’Brien Fleming boundary) based on the primary endpoint (PFS4) will be conducted once 40 evaluable patients have been recruited. If ≥ 7 out of 20 patients achieve PFS4, recruitment will continue to a maximum sample size of 50 evaluable patients per stratum. If ≥ 22 out of 50 patients achieve PFS4, T will be considered active in this group (alpha error: 0.025, power: 80%). To date, 35 patients (16 XPG-high and 15 XPG-low) have been enrolled from three countries and five centers. Recruitment is ongoing.

Two-stage seamless transition design from open-label single-arm to randomized double-arm clinical trials

2016 ◽  
Vol 27 (1) ◽  
pp. 158-171 ◽  
Author(s):  
Haolun Shi ◽  
Guosheng Yin
Keyword(s):  
Clinical Trials ◽  
Sample Size ◽  
Phase Ii ◽  
Therapeutic Effects ◽  
Operating Characteristics ◽  
Phase Ii Trials ◽  
Open Label ◽  
Two Stage ◽  
Trade Offs ◽  
Experimental Drug

Conventional phase II clinical trials use either a single- or multi-arm comparison scheme to examine the therapeutic effects of the experimental drug. Both single- and multi-arm evaluations have their own merits; for example, single-arm phase II trials are easy to conduct and often require a smaller sample size, while multiarm trials are randomized and typically lead to a more objective comparison. To bridge the single- and double-arm schemes in one trial, we propose a two-stage design, in which the first stage takes a single-arm comparison of the experimental drug with the standard response rate (no concurrent treatment) and the second stage imposes a two-arm comparison by adding an active control arm. The design is calibrated using a new concept, the detectable treatment difference, to balance the trade-offs between futility termination, power, and sample size. We conduct extensive simulation studies to examine the operating characteristics of the proposed method and provide an illustrative example of our design.

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