Statistical and Operational Challenges of the VALOR Trial: Mehta on the Promising Zone

Posted by Esha Senchaudhuri

Mar 26, 2015 4:00:00 PM

Last year Sunesis completed the VALOR trial, the first clinical study to make use of the groundbreaking promising zone design. The promising zone design implements an unblinded sample re-estimation after an interim look, but only if conditional power during the interim look falls within a designated promising zone. Although the VALOR trial did not confirm the efficacy of the new therapeutic, it provided the drug with the best possible chance to prove its efficacy.

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Topics: Promising Zone, Adaptive Clinical Trials, Statistical Innovations in Clinical Development


How Bayesian Strategies Can Expedite a Pediatric Clincial Trial Time by 20 - 40%

Posted by Esha Senchaudhuri

Mar 20, 2015 4:29:00 PM

Sometimes a new candidate drug for a pediatric study has already been tested on adults for safety and efficacy. We know that the drug is likely to work quite differently in children, but we do not know the degree to which the effects will be different. As a result, a conventional approach is to discard much of the information that has already gathered during studies of adults, and then to start from scratch with a pediatric trial.

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Topics: Bayesian Methods, Adaptive Clinical Trials, Pediatric


Embracing the Adaptive Mindset

Posted by Esha Senchaudhuri

Mar 10, 2015 11:35:00 AM

Most of us are primed to think about the design of adaptive clinical trials as a narrow set of techniques applied to a specific set of problems. If you’re worried about the power of your study, for example, you can turn to your toolkit of adaptive methods and find a suitable use for sample size re-estimation. If the concern is getting the best possible dose, a multi-arm study which drops doses after an interim look seems like the perfect solution.

Clinical development teams often look to adaptive designs, only after identifying specific objectives that a conventional trial may struggle to resolve. However, this approach has its limitations. An adaptive strategy might improve a trial design, even when a conventional strategy supplies a reasonable, (though less efficient,) alternative.   

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Topics: Adaptive Clinical Trials, Multi-Arm Studies


Adaptive vs. Group Sequential Designs in Survival Analysis

Posted by Esha Senchaudhuri

Mar 5, 2015 11:00:00 AM

 

 

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The Mehta-Pocock promising zone is often used to carry out unblinded sample size re-estimation during interim analysis. However, according to Jin Wang of Abbott Vascular, it can also be used to re-estimate follow-up times in the interim look of a survival analysis study.

According to simulations run by Jin, the Mehta-Pocock promising zone design offers the highest power and lowest Type 1 Error when compared to other common group sequential and adaptive designs. However, Jin questions whether this necessarily makes it the design of choice. 

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Topics: Adaptive Clinical Trials


Successful Adaptive Confirmatory Dose-Response Pediatric Study

Posted by Esha Senchaudhuri

Feb 26, 2015 4:48:00 PM

Cytel President and co-founder Cyrus Mehta has co-authored a paper on Infantile Hemangioma, recently published in the New England Journal of Medicine. The successful study was designed as an adaptive confirmatory dose-response which confirmed that 3mg per kilogram per day of propranolol for 6 months is an effective resolution for hemangioma.

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Topics: Cyrus Mehta, Adaptive Clinical Trials


How Proposed Regulatory Reforms Will Affect Your Clinical Trial

Posted by Esha Senchaudhuri

Feb 17, 2015 6:40:00 PM

21st Century Cures (also called Cures2015) is a bipartisan initiative undertaken by the Committee on Energy and Commerce of the US House of Representatives. Amongst the many factors motivating this landmark legislation is the concern  that regulatory procedures must keep up to date with innovations in clinical development. Cures2015 aims to reform the regulation of drugs, biologics and medical devices while increasing patient access to safe and effective drugs across therapeutic areas.

21st Century Cures presented a draft bill in January 2015 that would affect several regulatory procedures at agencies like the FDA. Included in the various proposals are reforms to the regulation of adaptive clinical trials and the use of Bayesian methods, and expedited approval processes for breakthrough therapies and medical devices. The landmark legislation also incentives improvements to Phase 2 trial design for certain therapeutic areas.   

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Topics: Bayesian Methods, Regulation, Medical Devices, Adaptive Clinical Trials


How to Shorten a Cardiovascular Outcome Trial By Two Years

Posted by Esha Senchaudhuri

Feb 10, 2015 5:28:00 PM

Cardiovascular outcome trials (CVOTs) have earned the reputation of being the untamable behemoths of the clinical world. Needless to say these trials are long and require extremely large sample-sizes. The Contrave LIGHT study required 8900 patients. The SAVOR TIMI trial enrolled 16,492 patients. Even the EXAMINE trial, which benefited from a promising zone design, required 650 patients. 

However, since the explosive controversy over the FDA’s conditional approval of anti-obesity drug Contrave four years ago, there is much we have learned about how to make these trials shorter while also diminishing the financial risks of investing in them. For example, one of our clients managed to shorten the expected study length of an a CVOT by two years using a four point MACE Assessment (see below). 

In this post, we explore some of the lessons we have learned when designing these large-scale clinical trials.  

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Topics: Cyrus Mehta, Promising Zone, Cytel Strategic Consulting, Interim Analyses, Program and Portfolio Optimization, Cardiovascular, Clinical Development Strategy, Adaptive Clinical Trials


Clinical Development & Statistical Methodology for Cardiovascular Risk Assessment

Posted by Cytel

Feb 3, 2015 2:00:00 PM

A new publication co-authored by Cytel Co-Founder and President Cyrus Mehta considers a range of clinical development methods for cardiovascular outcome trials. Cardiovascular outcome trials, (often referred to as CVOTs), reflect safety standards implemented by the FDA and EMA to determine whether or not new drugs impose undue cardiovascular risk on patients. CVOTs typically occur after Phase 3 trials, and often make up for the slow rate of observed events by enrolling thousands of patients. This adds substantial delay in getting a drug to market.

In this paper, Cyrus and his co-authors explore how adaptive and group sequential methods might shorten this process without compromising the quality of the trial. In particular they consider increases in sample size and early stopping boundaries. They consider the possible benefits of unblinded sample size re-estimation (also known as the Promising Zone Design) in CVOT trials. 

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Topics: Cardiovascular, Group Sequential, Adaptive Clinical Trials


Adaptive Design and Bayesian Statistics: 5 Years Later (Podcast)

Posted by Esha Senchaudhuri

Jan 29, 2015 4:00:00 PM

February 2015 marks the five year anniversary of the FDA’s Guidance on Adaptive Design Clinical Trials for Drug and Biologics, as well as the FDA’s Guidance on the Use of Bayesian Statistics in Medical Device Clinical Trials. In honor of the five year anniversary of both sets of guidance, the DIA will hold a special joint conference between its Adaptive Design working group and its working group on Bayesian Statistics.

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Topics: Bayesian Methods, Adaptive Clinical Trials


Adaptive Clinical Trial Strategies for the Limited Early Phase Budget

Posted by Esha Senchaudhuri

Jan 22, 2015 9:00:00 AM

 

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The Journal of the American Medical Association recently published an article entitled ‘The Anatomy of Medical Research: US and International Comparisons.’ The stated objective of the study was to “quantify total public and private investment and personnel (economic inputs) and to evaluate resulting patents, publications, drug and device approvals, and value created (economic outputs)“ [1]

Amongst the many findings of this comprehensive study, a vital observation is the reduction of early phase spending by about 4% per year from 2004 to 2012. One attribution for this decline involves the financial constraints placed upon proof-of-concept trials, particularly when compared to the expected financial benefits of Phase 3 trials and medical devices. According to the authors, “Many new basic discoveries that have probable clinical value are stymied by financial constraints at the critical proof-of-concept stage, where utility in humans is demonstrated.” [1] They add that the number of new discoveries that will be underfunded at the proof-of-concept stage is expected to increase.

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Topics: Dose-Finding, Early Phase Trials, Proof-of-Concept, Case Study, Adaptive Clinical Trials


Why Drugs Fail in Phase 3: A Cytel Infographic

Posted by Esha Senchaudhuri

Jan 20, 2015 10:30:03 AM

According to a recent Cytel Whitepaper on Adaptive Clinical Trials, 50% of Phase 3 trials eventually fail. This new Cytel Infographicoffers a breakdown of why so many drugs fail in Phase 3.

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Topics: Early Phase Trials, Clinical Development Strategy, Phase 3, Adaptive Clinical Trials


Clinical Drug Development: Predictions & Trends for 2015

Posted by Cytel

Jan 6, 2015 4:00:00 PM

As we head into the new year, the life-sciences industry can look forward to some long awaited advances in pharmaceutical drug development. Here are our predictions for top trends to look out for in 2015.

1: The Arrival of Adaptive Financing:

Adaptive financing was an idea that was cultivated and nurtured by members and affiliates of Cytel. It is the idea that a financial strategy can be built around outcomes that are observed at certain decision points during clinical development (for example, at interim analyses.) Constructing designs with adaptive financing in mind helps provide potential investors and study sponsors with a monetary ballpark of how much innovation will cost, and how much they have the potential to save. This helps overcome one of the biggest bottlenecks in implementing safer and more efficient adaptive trials, namely the perception by many in the industry that these trials are risky.

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Topics: Entrepreneurship, Adaptive Clinical Trials


Early Phase Development Strategy: Bayesian Methods for Go/No-Go Rules

Posted by Esha Senchaudhuri

Dec 18, 2014 3:40:00 PM

Earlier this week, we at Cytel enjoyed a riveting in-house discussion on the uses of Bayesian decision rules for Go/No-Go (GNG) decision-making. GNG rules establish the trajectory of a particular clinical program’s development by assessing whether or not a trial has met particular objects (e.g. target regions for PK, PD and safety endpoints.)

Traditionally, statisticians have used p-values and confidence intervals to construct GNG rules. However, moving to the Bayesian paradigm opens up exciting new possibilities for clinical development strategy. Our discussion earlier this week centered around three key benefits of using Bayesian statistics for GNG decision-making:

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Topics: Early Phase Trials, Clinical Development Strategy, Adaptive Clinical Trials


Adaptive Designs for Infectious Diseases Clinical Development Strategy

Posted by Esha Senchaudhuri

Dec 11, 2014 1:14:00 PM

 

A common framework for the clinical development of vaccines involves the study of several candidate compounds in Phase 1 followed by the selection of potential vaccine regimens for study in Phase 2 and Phase 3. In the attached presentation, Cytel Consulting’s Jim Bolognese compares traditional and adaptive Phase 1/Phase 2 studies for vaccines and infectious diseases, providing simulations results for both 2-stage and multi-stage adaptive designs. Jim also outlines a structure for a Hybrid Adaptive Study.

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Topics: Infectious Diseases, Clinical Development Strategy, Adaptive Clinical Trials


Drug Supply Planning for Dose-Ranging Adaptive Trials

Posted by Esha Senchaudhuri

Dec 9, 2014 12:17:28 PM

When planning a conventional trial, one can anticipate the drug supply necessary for the trial by determining how the number of patients reflected in the sample size will distribute across the trial sites. Implementing an adaptive trial, by contrast, raises many challenges for predicting the necessary drug supply. It can require planning for different sample sizes depending on the outcome of an interim look; or preparing different dosages if certain arms of a multi-arm trial are to drop after the interim look. In the case of a biomarker-driven adaptive design, determining adequate drug supply may require the ability to predict which doses are necessary for different subpopulations at particular trial sites.

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Topics: Nitin Patel, Access to Slides PDF, Bayesian Methods, Interim Analyses, optimization, Dose-Finding, Adaptive Clinical Trials


Ranking Adaptive Dose-Finding Designs using Clinical Utility Functions

Posted by Esha Senchaudhuri

Nov 12, 2014 4:04:25 PM

Clinical utility functions provide Phase 2 trial sponsors with an intuitive metric by which to measure the quality of a selected dose. Such functions reveal the efficacy-to-tolerability ratio of doses under consideration, thereby enabling trials to move forward with doses that are highly effective and which have minimal side-effects. While this is arguably the most popular use of clinical utility functions, they can also help trial designers determine which design ought to be chosen for dose-finding studies. A design which consistently chooses doses with high clinical utility should instill greater confidence than those which often miss this critical target. 

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Topics: Dose-Finding, Adaptive Clinical Trials


New Exploratory Trial Method Translates into Better Financial Strategy

Posted by Esha Senchaudhuri

Nov 4, 2014 8:30:00 AM

A key stage of exploratory drug development is implementing a proof-of-concept study to demonstrate the safety of a drug. Given the importance of accurate dose-finding for Phase 3 success, methodological improvements to proof-of-concept studies in Phase 2 can translate into greater likelihood of getting a drug to market. 

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Topics: Oncology, Access to Slides PDF, Enrichment, Safety, Precision Medicine, Entrepreneurship, R&D, Adaptive Clinical Trials


Michael Proschan on 'Blinded Adaptations, Permutations and t-tests' (Link to Slides)

Posted by Cytel

Oct 30, 2014 10:28:00 AM

 During last week’s East Users Group Meeting, Michael Proschan of the NIH and NIAID, gave a presentation on ‘Blinded Adaptations, Permutations and t-tests.’ Given the close connection between adaptive t-tests and adaptive permutation tests, Proschan argued that it is possible to determine the validity of an adaptive t-test from the validity of an adaptive permutation test. Proschan concludes that in adaptive settings, “permutation tests are often valid in adaptive settings, even if blind is maintained.”

Michael's slides are available below. You can also find two of his recent papers on blinded adaptations in the 'Related Items of Interest' section.  

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Topics: permutations, Blind and Unblind Trials, t-tests, Adaptive Clinical Trials


Adaptive Dose Finding Using Toxicity Probability Intervals

Posted by Esha Senchaudhuri

Oct 28, 2014 9:30:00 AM

Phase 1 oncology trials typically use either rule-based methods or model-based methods to determine the most acceptable level of dose toxicity with which to move forward in Phase 2. This level of toxicity, called the maximum tolerated dose (or the MTD), is the dose which best balances the medical benefits of a higher dose with the risk of toxicity which comes from subjecting a patient to that same dose. Both rule-based methods and model-based methods determine the MTD by relying on small cohorts of patients who test a set of doses against their dose limiting toxicity.

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Topics: Oncology, East 6.3, Access to Slides PDF, East ESCALATE, Adaptive Clinical Trials


5 Scenarios When ‘Keep it Simple’ May Be Bad Advice for Clinical Trial Designers

Posted by Esha Senchaudhuri

Sep 18, 2014 10:44:00 AM

When designing clinical trials, many trial designers are advised to keep the trial simple. Prima facie, the keep it simple principle seems like sound advice. There are various logistical uncertainties that arise when implementing a clinical trial, and the more simple a trial – so conventional wisdom says – the easier it is to respond to these uncertainties.

According to Zoran Antonijevic, a Senior Director at Cytel Consulting, there is reason to doubt such conventional wisdom. After all, flexibility is hardly a virtue of a traditional trial design. Simple designs may seem to make it easier to monitor data and report results. However, a flexible design can better address remaining uncertainties in product development. These uncertainties are related to treatment effect, dose selection, or a sub-population that would experience the best benefit/risk from the treatment.

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Topics: Oncology, Promising Zone, sample size re-estimation, Enrichment, Cytel Consulting, Efficacy, Interim Analyses, forecasting, optimization, Program and Portfolio Optimization, R&D, Adaptive Clinical Trials


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