Trial Results: PALbociclib CoLlaborative Adjuvant Study (PALLAS)

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Trial Results: PALbociclib CoLlaborative Adjuvant Study (PALLAS)

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The PALLAS trial, a collaborative effort between The Austrian Breast & Colorectal Cancer Study Group (ABCSG), Alliance Foundation Trials (AFT), the Breast International Group (BIG), PrECOG, LLC, the German Breast Group, and the NSABP Foundation, was designed to compare the combination of at least five years of standard adjuvant endocrine therapy plus two years of palbociclib (IBRANCE®, manufactured by Pfizer) treatment versus at least five years of standard adjuvant endocrine therapy in patients with HR+, HER2- early invasive breast cancer.

In late May, the collaborators announced that the independent Data Monitoring Committee for the trial determined the study is unlikely to show a statistically significant improvement in the primary endpoint of invasive disease-free survival following a preplanned interim analysis. That is, there is little chance of palbociclib reducing the risk of recurrence. No new safety signals were observed in patients receiving palbociclib, which has been proven effective in advanced breast cancer. PALLAS patients in the active phase of the trial will be counseled by their physicians. All patients will move to protocol-defined extended follow-up. Long-term follow-up of patient outcomes will proceed as planned.

“There remains a great need to improve outcomes for patients with HR+ breast cancer. Our collaborative academic group will continue to closely follow our PALLAS patients and hope to learn from the PALLAS dataset and correlative science how best to improve outcomes in this population,” said Erica L. Mayer, MD, MPH (Dana-Farber Cancer Institute, Harvard Medical School), global PALLAS trial chair (pictured). “Despite this futility result, the PALLAS trial represents a remarkable collaboration between academic and industry partners, and we hope can serve as a model of cooperative trial conduct.”

Angela M. DeMichele, MD, MSCE (University of Pennsylvania), pictured, served as co-principal investigator for PALLAS on behalf of PrECOG, LLC. She is currently co-chair of the ECOG-ACRIN Breast Cancer Committee. More than 400 participating clinical sites in 21 countries enrolled a total of 5,796 patients. The study opened in August 2015. The global recruitment aim was met on schedule, on November 30, 2018, displaying the well-concerted interplay of participating academic groups and their profound experience in clinical research.

Read the full press release on the PrECOG website.

About PrECOG

PrECOG, LLC is a cancer research group formed as a not-for-profit limited liability company in 2006 by the ECOG Research and Education Foundation, Inc. It operates outside of the National Cancer Institute’s federal funding structure, known as the National Clinical Trials Network. A central focus of PrECOG is to support the overall scientific research goals of the ECOG-ACRIN Cancer Research Group. PrECOG aims to reduce the burden of cancer by advancing research in all aspects of cancer care and thereby improve survival, patient benefit, and quality of life. The current PrECOG portfolio includes phase one and two multi-center trials, as well as US-based and multi-national phase three trials. For further information, please visit

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