Application of the Continual Reassessment Method to Dose-finding Studies in Regional Anesthesia

2013 ◽  
Vol 119 (1) ◽  
pp. 29-35 ◽  
Author(s):  
Abhinav Kant ◽  
Pawan Kumar Gupta ◽  
Sarah Zohar ◽  
Sylvie Chevret ◽  
Philip M. Hopkins
Keyword(s):  
Prospective Trial ◽  
Dose Finding ◽  
Continual Reassessment Method ◽  
Double Blind ◽  
Upper Limb Surgery ◽  
Continual Reassessment ◽  
Starting Dose ◽  
Statistical Program ◽  
Supraclavicular Block ◽  
Dose Levels

Abstract Background Previously reported estimates of the ED95 doses for local anesthetics used in brachial plexus blocks vary. The authors used the continual reassessment method, already established in oncology trials, to determine the ED95 dose for 0.5% bupivacaine for the ultrasound-guided supraclavicular block. Methods A double-blind, prospective trial was scheduled for 40 patients of American Society of Anesthesiologists class I–III presenting for upper limb surgery and supraclavicular block. The study dose to be administered was arbitrarily divided into six dose levels (12, 15, 18, 21, 24, and 27 ml) with a priori probabilities of success of 0.5, 0.75, 0.90, 0.95, 0.98, and 0.99 respectively. A continual reassessment method statistical program created a dose–response curve, which would shift direction depending on the success or failure of the block. Our starting dose was 21 ml and the next allocated dose was reestimated by the program to be the dose level with the updated posterior response probability closest to 0.95. Results After recruitment of eight patients, our initial dose levels and associated probabilities were deemed too low to determine the ED95. Updated a prioris were calculated from the statistical program, and the study recommenced with a new starting dose of 30 ml. On completion, the ED95 dose was estimated to be 27 ml (95% CI, 24–28 ml). Conclusions The continual reassessment method trial design provided a credible estimate for the ED95 dose for 0.5% bupivacaine for our technique of supraclavicular block and may be of value as a statistically robust method for dose-finding studies in anesthesiology.

scholarly journals Would the Recommended Dose Have Been Different Using Novel Dose-Finding Designs? Comparing Dose-Finding Designs in Published Trials

2021 ◽  
pp. 1024-1034
Author(s):  
Rebecca B. Silva ◽  
Christina Yap ◽  
Richard Carvajal ◽  
Shing M. Lee
Keyword(s):  
Maximum Tolerated Dose ◽  
Dose Finding ◽  
Simulation Studies ◽  
Toxicity Data ◽  
Continual Reassessment Method ◽  
Optimal Interval ◽  
Patient Allocation ◽  
Continual Reassessment ◽  
Continuous Use ◽  
Dose Levels

PURPOSE Simulation studies have shown that novel designs such as the continual reassessment method and the Bayesian optimal interval (BOIN) design outperform the 3 + 3 design by recommending the maximum tolerated dose (MTD) more often, using less patients, and allotting more patients to the MTD. However, it is not clear whether these novel designs would have yielded different results in the context of real-world dose-finding trials. This is a commonly mentioned reason for the continuous use of 3 + 3 designs for oncology trials, with investigators considering simulation studies not sufficiently convincing to warrant the additional design complexity of novel designs. METHODS We randomly sampled 60 published dose-finding trials to obtain 22 that used the 3 + 3 design, identified an MTD, published toxicity data, and had more than two dose levels. We compared the published MTD with the estimated MTD using the continual reassessment method and BOIN using target toxicity rates of 25% and 30% and toxicity data from the trial. Moreover, we compared patient allocation and sample size assuming that these novel designs had been implemented. RESULTS Model-based designs chose dose levels higher than the published MTD in about 40% of the trials, with estimated and observed toxicity rates closer to the target toxicity rates of 25% and 30%. They also assigned less patients to suboptimal doses and permitted faster dose escalation. CONCLUSION This study using published dose-finding trials shows that novel designs would recommend different MTDs and confirms the advantages of these designs compared with the 3 + 3 design, which were demonstrated by simulation studies.

scholarly journals A comparison of phase I dose-finding designs in clinical trials with monotonicity assumption violation

2020 ◽  
Vol 17 (5) ◽  
pp. 522-534
Author(s):  
Rachid Abbas ◽  
Caroline Rossoni ◽  
Thomas Jaki ◽  
Xavier Paoletti ◽  
Pavel Mozgunov
Keyword(s):  
Phase I ◽  
Dose Level ◽  
Partial Ordering ◽  
Dose Finding ◽  
Continual Reassessment Method ◽  
Optimal Interval ◽  
Correct Dose ◽  
Monotonicity Assumption ◽  
Continual Reassessment ◽  
Dose Levels

Background/Aims In oncology, new combined treatments make it difficult to order dose levels according to monotonically increasing toxicity. New flexible dose-finding designs that take into account uncertainty in dose levels ordering were compared with classical designs through simulations in the setting of the monotonicity assumption violation. We give recommendations for the choice of dose-finding design. Methods Motivated by a clinical trial for patients with high-risk neuroblastoma, we considered designs that require a monotonicity assumption, the Bayesian Continual Reassessment Method, the modified Toxicity Probability Interval, the Bayesian Optimal Interval design, and designs that relax monotonicity assumption, the Bayesian Partial Ordering Continual Reassessment Method and the No Monotonicity Assumption design. We considered 15 scenarios including monotonic and non-monotonic dose–toxicity relationships among six dose levels. Results The No Monotonicity Assumption and Partial Ordering Continual Reassessment Method designs were robust to the violation of the monotonicity assumption. Under non-monotonic scenarios, the No Monotonicity Assumption design selected the correct dose level more often than alternative methods on average. Under the majority of monotonic scenarios, the Partial Ordering Continual Reassessment Method selected the correct dose level more often than the No Monotonicity Assumption design. Other designs were impacted by the violation of the monotonicity assumption with a proportion of correct selections below 20% in most scenarios. Under monotonic scenarios, the highest proportions of correct selections were achieved using the Continual Reassessment Method and the Bayesian Optimal Interval design (between 52.8% and 73.1%). The costs of relaxing the monotonicity assumption by the No Monotonicity Assumption design and Partial Ordering Continual Reassessment Method were decreases in the proportions of correct selections under monotonic scenarios ranging from 5.3% to 20.7% and from 1.4% to 16.1%, respectively, compared with the best performing design and were higher proportions of patients allocated to toxic dose levels during the trial. Conclusions Innovative oncology treatments may no longer follow monotonic dose levels ordering which makes standard phase I methods fail. In such a setting, appropriate designs, as the No Monotonicity Assumption or Partial Ordering Continual Reassessment Method designs, should be used to safely determine recommended for phase II dose.

scholarly journals A Bayesian dose-finding design for outcomes evaluated with uncertainty

2021 ◽  
pp. 174077452110015
Author(s):  
Matthew J Schipper ◽  
Ying Yuan ◽  
Jeremy MG Taylor ◽  
Randall K Ten Haken ◽  
Christina Tsien ◽  
...  
Keyword(s):  
Phase I ◽  
Phase I Trial ◽  
Data Augmentation ◽  
Maximum Tolerated Dose ◽  
Dose Finding ◽  
Continual Reassessment Method ◽  
Number Of Patients ◽  
Continual Reassessment ◽  
Partially Observed ◽  
Dose Limiting Toxicity

Introduction: In some phase I trial settings, there is uncertainty in assessing whether a given patient meets the criteria for dose-limiting toxicity. Methods: We present a design which accommodates dose-limiting toxicity outcomes that are assessed with uncertainty for some patients. Our approach could be utilized in many available phase I trial designs, but we focus on the continual reassessment method due to its popularity. We assume that for some patients, instead of the usual binary dose-limiting toxicity outcome, we observe a physician-assessed probability of dose-limiting toxicity specific to a given patient. Data augmentation is used to estimate the posterior probabilities of dose-limiting toxicity at each dose level based on both the fully observed and partially observed patient outcomes. A simulation study is used to assess the performance of the design relative to using the continual reassessment method on the true dose-limiting toxicity outcomes (available in simulation setting only) and relative to simple thresholding approaches. Results: Among the designs utilizing the partially observed outcomes, our proposed design has the best overall performance in terms of probability of selecting correct maximum tolerated dose and number of patients treated at the maximum tolerated dose. Conclusion: Incorporating uncertainty in dose-limiting toxicity assessment can improve the performance of the continual reassessment method design.

A prospective PGx and PK/PD dose-finding study of irinotecan based on UGT1A1*6 and *28 genotyping (UGT0601)

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e14560-e14560
Author(s):  
T. Esaki ◽  
T. Satoh ◽  
T. Ura ◽  
T. Tsujinaka ◽  
Y. Sasaki ◽  
...  
Keyword(s):  
Initial Dosage ◽  
Maximum Tolerated Dose ◽  
Dose Finding ◽  
Hematological Toxicity ◽  
Continual Reassessment Method ◽  
Continual Reassessment ◽  
Finding Study ◽  
Dose Finding Study ◽  
Grade 3 ◽  
Dose Limiting Toxicity

e14560 Background: UGT1A1*6 as well as UGT1A1*28 polymorphisms is associated with decreased glucuronidation of SN-38, the active metabolite of irinotecan (CPT-11). Although the maximum tolerated dose (MTD) and the recommended dose (RD) in Hetero was determined 150 mg/m2 (approval dose in Japan), those of Homo were unknown. Methods: Pts received prior chemotherapies except for CPT-11 for metastatic gastrointestinal cancer were enrolled. UGT1A1 polymorphisms were categorized into Wild(*1/*1), Hetero(*1/*28, *1/*6), and Homo(*28/*28, *6/*6, *28/*6). CPT-11 was administered biweekly. Starting doses were 150 mg/m2 in Wild, 100 mg/m2 in Hetero, and 75 mg/m2 in Homo. DLT was defined as grade 4 hematological, or grade 3 non-hematological toxicity. MTD closest to dose-limiting toxicity (DLT) appearance of 30% was guided by the continual reassessment method in the cohort of Hetero and Homo. DLT and pharmacokinetic (PK) sampling was evaluated during the 1st cycle. Results: Eighty-two pts were enrolled from November 2006 to November 2008 (Wild, Hetero, Homo: 41, 20, and 21, respectively). The dose level reached at 150 mg/m2 in Homo. At 150 mg/m2, DLT was observed in six pts of Homo (grade 4 neutropenia, grade 3 diarrhea: 6 and 1, respectively). The probability of DLTs were 22.2% at 125 mg/m2, and 37.4% at 150 mg/m2. The MTD was determined 150 mg/m2 in pts with Homo group. However, the incidences of grade 3/4 neutropenia at 150 mg/m2 during the 1st cycle were 9.8% (4/41), 18.8% (3/16), and 62.5% (10/16) in Wild, Hetero, and Homo, respectively. And the second administration was delayed 7 days or more in most pts in Homo (63% at 150 mg/m2). In one pt of Homo for *28/*28 died of septic shock during the 2nd cycle. SN-38 AUC (0–24h, ng*hr/mL, median) was 239 in Wild, 237 in Hetero, and 410 in Homo. Pts with Homo showed the different trend of PK/PD compared to those with Wild and Hetero. Conclusions: The MTD was 150 mg/m2 in pts with Homo group and the most frequent DLT was grade 4 neutropenia. However, our findings suggest that 150 mg/m2 q2w is difficult to recommend and the initial dosage and administration should be considered carefully for pts with Homo. [Table: see text]

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