Realization of simulations for blinded internal pilot study based on web

AbstractMisspecification of the designing parameters in the planning of a controlled clinical trial may yield an underpowered or an overpowered study. Internal pilot study, a kind of adaptive design, has gained increased attention for its allowing for sample size adjustment, especially blinded sample size adjustment that do not affect the type I error rate. Several methods were proposed to implement internal pilot design in recent years and some software emerges to simulate or implement it. But most of the software is only running on a stand-alone terminal or Client/Server(C/S) mode. We develop a system to simulate it based on Browser/Server(B/S) mode and realized on web. It allows the web users to input corresponding parameters from the web browser such as Internet Explorer to make simulations. The system was constructed with generic database schema design method and coded with Microsoft Visual Basic and Active Server Pages (ASP) programming languages. Web users on internet can use the system to make blinded variance estimate, sample size adjustment and randomization test for internal pilot study. The application of the simulation is demonstrated through an example. Not only blinded sample size adjustment is implemented but also a randomization test is performed. With applications of blinding one-sample variance for sample size recalculation and randomization test, the type I error rate is also controlled successfully

Drug-coated balloon angioplasty with provisional stenting versus primary stenting for the treatment of de novo coronary artery lesions: REC-CAGEFREE I trial rationale and design

Background: Percutaneous coronary intervention (PCI) with primary stenting, which stands for stent implantation regardless of obtaining satisfactory results with balloon angioplasty, has superseded conventional plain old balloon angioplasty with provisional stenting. With drug-coated balloon (DCB), primary DCB angioplasty with provisional stenting has shown non-inferiority to primary stenting for de novo coronary small vessel disease. However, the long-term efficacy and safety of such a strategy to the primary stenting on clinical endpoints in de novo lesions without vessel diameter restrictions remain uncertain. Study design: The REC-CAGEFREE I is an investigator-initiated, multicenter, randomized, open-label trial aimed to enroll 2270 patients with acute or chronic coronary syndrome from 43 interventional cardiology centers in China to evaluate the non-inferiority of primary paclitaxel-coated balloons angioplasty to primary stenting for the treatment of de novo, non-complex lesions without vessel diameter restrictions. Patients who fulfill all the inclusion and exclusion criteria and have achieved a successful lesion pre-dilatation will be randomly assigned to the two arms in a 1:1 ratio. Protocol-guided DCB angioplasty and bailout stenting after unsatisfactory angioplasty are mandatory in the primary DCB angioplasty group. The second-generation sirolimus-eluting stent will be used as a bailout stent in the primary DCB angioplasty group and the treatment device in the primary stenting group. The primary endpoint is the incidence of Device-oriented Composite Endpoint (DoCE) within 24 months after randomization, including cardiac death, target vessel myocardial infarction, and clinically and physiologically indicated target lesion revascularization. Discussion: The ongoing REC-CAGEFREE I trial is the first randomized trial with a clinical endpoint to assess the efficacy and safety of primary DCB angioplasty for the treatment of de novo, non-complex lesions without vessel diameter restrictions. If non-inferiority is shown, PCI with primary DCB angioplasty could be an alternative treatment option to primary stenting. Trial registration: Registered on clinicaltrial.gov (NCT04561739)

Randomized evaluation of 5-month Ticagrelor monotherapy after 1-month dual-antiplatelet therapy in patients with acute coronary syndrome treated with drug-coated balloons: REC-CAGEFREE II trial rationale and design

Background: Patients treated with drug-coated balloons (DCB) have the theoretical advantage of adopting a low-intensity antiplatelet regimen due to the absence of struts and polymers. Nevertheless, the optimal antiplatelet strategy for patients undergoing DCB-only treatment remains a topic of debate and has not been investigated in randomized trials. Methods: The REC-CAGEFREE II is an investigator-initiated, prospective, open-label, multi-center, randomized, non-inferiority trial aimed to enroll 1908 patients from ≥ 40 interventional cardiology centers in China to evaluate the non-inferiority of an antiplatelet regimen consisting of Aspirin plus Ticagrelor for one month, followed by five months Ticagrelor monotherapy, and then Aspirin monotherapy for six months (Experimental group) compared to the conventional treatment of Aspirin plus Ticagrelor for 12 months (Reference group) in patients with acute coronary syndrome (ACS) who have undergone percutaneous coronary intervention (PCI) using paclitaxel-coated balloons (DCB) exclusively. Participants will be randomly assigned to the Experimental or Reference group in a 1:1 ratio. The randomization will be stratified based on the center and the type of lesion being treated (De novo or in-stent restenosis). The primary endpoint is net adverse clinical events (NACE) within 12 months of PCI, which includes the composite of all-cause death, any stroke, any myocardial infarction, any revascularization and Bleeding Academic Research Consortium (BARC) defined type 3 or 5 bleeding. The secondary endpoint, any ischemic and bleeding event, which includes all-cause death, any stroke, MI, BARC-defined type 3 bleeding, any revascularization, and BARC-defined type 2 bleeding events, will be treated as having hierarchical clinical importance in the above order and analyzed using the win ratio method. Discussion: The ongoing REC-CAGEFREE II trial aims to assess the efficacy and safety of a low-intensity antiplatelet approach among ACS patients with DCB. If non-inferiority is shown, the novel antiplatelet approach could provide an alternative treatment for ACS patients with DCB

An algorithm for computing profile likelihood based pointwise confidence intervals for nonlinear dose-response models.

This study was inspired by the need to estimate pointwise confidence intervals (CIs) for a nonlinear dose-response model from a dose-finding clinical trial. Profile likelihood based CI for a nonlinear dose response model is often recommended. However, it is still not commonly used in dose-finding studies because it cannot generally be calculated explicitly. Most previous research has mainly focused on the performance of the profile likelihood based CI method compared with other common approaches. However, there are still no reports on computing profile likelihood based pointwise CIs for an entire dose-response curve. Based on a previous dose-finding trial with binary-response data, this present study proposed to calculate profile likelihood based pointwise CIs by using the bisection method with proper calculation order for doses in the curve plus crude search when the expected response is close to a boundary. The convergence could be improved by applying appropriate starting values for the optimization procedure with straightforward programming techniques. The algorithm worked well in most cases based on the simulation study and it can be applied more generally to other dose-response models, and other type of data like normally distributed response. It would indeed be great to be able to use profile likelihood approaches more routinely when constructing pointwise CIs for nonlinear dose-response models

Considerations on the clinical development of COVID-19 vaccine from trial design perspectives

COVID-19 has become a global pandemic, and an effective vaccine is needed. During the outbreak, the urgency for developing candidate vaccines has brought distinct challenges to clinical development. An efficacy trial, which measures whether the vaccine reduces the incidence of disease, is ordinarily required to fully evaluate vaccine efficacy. However, emergency use may be possible if promising immunogenicity results are observed. A ring vaccination trial, which recruits subjects connected to a known case either socially or geographically, is a solution to evaluate vaccine efficacy and control the spread of the disease simultaneously although its conduct is challenging. Nevertheless, when COVID-19 becomes a recurrent epidemic, an ‘individual-level’ efficacy trial is preferred. Innovative statistical designs, including seamless design, platform trial, master protocol design, are helpful to accelerate clinical development. A seamless Phase I/II design has been applied in multiple COVID-19 vaccine studies to date. However, Phase II/III design should be done very carefully. The control of type I error, maintaining trial blinding and statistical methods leading to unbiased estimates should be pre-specified in the clinical protocol. A Data Safety Monitoring Board is especially important, given the need to assure an adequate level of safety when society want a safe and effective vaccine

A novel Bayesian seamless phase I/II design.

This paper proposes a novel bayesian phase I/II design featuring using a hybrid mTPI method in phase I for targeting the MTD level and a randomization allocation schema for adaptively assigning patients to desirable doses in phase II. The mechanism of simultaneously escalating dose in phase I and expanding promising doses to phase II is inherited from a design proposed in literature. Extensive simulation studies indicate that our proposed design can vastly save sample size and efficiently assign more patients to optimal dose when compared to two competing designs

An evaluation roadmap for critical quality attributes from tier 1 in analytical similarity assessment.

Analytical similarity assessment of critical quality attributes (CQAs) serves as a foundation for the development of biosimilar products and facilitates an abbreviated subsequent clinical evaluation. In this study, we establish a statistical evaluation roadmap with statistical approaches for some selected CQAs from Tier 1, because they are most relevant to clinical outcomes and require the most rigorous statistical methods. In the roadmap, we incorporate 3 methods-ranking and tier assignment of quality attributes, the equivalence test, and the Mann-Whitney test for equivalence-that are important to determine analytical similarity between the reference and biosimilar products. For the equivalence test, we develop a power calculation formula based on the two one-sided tests procedure. Exact sample sizes can be numerically calculated. Then, we propose a flexible idea for selecting the number of reference lots (nR) and the number of biosimilar lots (nT) to adjust for serious unbalanced sample sizes. From results of extensive simulations under various parameter settings, we obtain a workable strategy to determine the optimum sample size combination (nT, nR) for the equivalence test of CQAs from Tier 1. R codes are provided to facilitate implementation of the roadmap and corresponding methods in practice

Assessment of a block curriculum design on medical postgraduates’ perception towards biostatistics: a cohort study

Abstract Background Biostatistics is a key but challenging subject in medical curricula that is usually delivered via a didactic approach in China. However, whether it is the best teaching approach to improve the learner’s competency, especially for medical postgraduates is yet to be proved. Therefore, a block curriculum design was initially developed to provide selective education to the postgraduates towards the professional career of their interest. A questionnaire was designed to assess the students’ perceptions toward biostatistics as these affective factors might impact the learning process. Thus, the present study aimed to detect whether the new block curriculum design could promote the students’ positive perceptions and further improve the course achievement. Methods This cohort study investigated and assessed the perceptions toward biostatistics of the first-year postgraduates undergoing traditional teaching and block teaching, respectively. Structural equation modeling was applied to explore the association between perception and course achievement in the block teaching group. Results With a response rate of 97.84 and 96.67% from the two cohorts respectively, 499 block teaching postgraduates had more positive perceptions as compared to 465 traditionally teaching postgraduates with Likert 5-point agreement response mean of 3.50 vs. 3.31 for course value, 3.66 vs. 2.97 for course comment, and 4.29 vs. 4.10 for expectation. Moreover, block teaching students presented superior confidence about academic statistical knowledge, and therefore, 77.96% of them approved of the new teaching approach. Age, specialty, research experience, logical thinking capacity, mathematical basics, and computer basics might influence the postgraduates’ self-assessment ability (all P < 0.05). Structural equation modeling confirmed a positive correlation between perceptions and the course achievements with a reasonable fit. Conclusions The block curriculum design in the biostatistics course improved the postgraduates’ positive perception and may have had a positive role in improving postgraduates’ achievement in learning biostatistics