Upcoming Lecture: 19 August 2026
Event Information
- Date: 19 August 2026
- Time: 1:00 p.m. EST | 5:00 p.m. UTC | 3:00 a.m. AEDT
- Title: "Statistical Challenges in the I-SPY2 Sequential Multiple Assignment
Randomized Trial"
Abstract
I-SPY2 is a long-running phase 2 platform trial that evaluates novel neoadjuvant treatments for locally advanced breast cancer to identify those with high efficacy that are likely to be successful in phase 3 trials. Recently, I-SPY2 was reconfigured as a sequential multiple assignment randomized trial (SMART), with up to three stages of therapy. At the first stage, a patient is assigned to a tumor-subtype-specific therapy. If the patient fails to show a satisfactory response, the patient is assigned to a second subtype-specific therapy, and receives a third, rescue therapy if response is still not achieved. The I-SPY2 SMART thus supports identification of highly efficacious entire treatment strategies, also known as treatment regimes. A hallmark of I-SPY2 since its inception has been the use of Bayesian response-adaptive randomization (bRAR) to update randomization probabilities to give greater weight to treatments that appear more efficacious based on data from previous patients. The transition of I-SPY2 to a SMART required development of a new, analogous bRAR scheme to update randomization probabilities at each stage. In the first part of this talk, I will present the bRAR approach developed by the I-SPY2 statistical team, which updates randomization probabilities based on the posterior probability that treatments are part of an optimal treatment regime and which is use in the ongoing trial. The I-SPY2 SMART also provides an illustrative context for the range of questions that can be of interest when treatments are administered sequentially as part of a strategy. In the second part of the talk, I will discuss some of these questions.
Biography
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Marie Davidian is J. Stuart Hunter Distinguished Professor of Statistics at North Carolina State University (NC State). Her research interests include methodology for the design and analysis of clinical trials and observational studies, for causal inference and dynamic treatment regimes, for analysis of missing and mismeasured data, and for longitudinal data analysis. Marie is a Fellow of the American Statistical Association (ASA), Institute of Mathematical Statistics, and the American Association for the Advancement of Science, and an elected member of the International Statistical Institute and has been the recipient of several awards and recognitions, including Honorary Life Membership in the IBS. Marie was inaugural Coordinating Editor in 2000-2002 of Biometrics and served as the first Executive Editor in 2006-2017, and she was President of the Eastern North American Region (ENAR) of IBS in 2004 and President of ASA in 2013. Over the past decade, she has collaborated on the design and conduct of several completed and ongoing sequential multiple assignment randomized trials (SMARTs).
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The IBS Distinguished Lecture Series is open to all IBS members worldwide.
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