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Medicine Matters oncology

Overall, data from the PALLAS trial suggests to us that the addition of palbociclib to ongoing adjuvant endocrine therapy has not improved outcomes compared to ongoing adjuvant endocrine therapy alone in patients with stage 2 or 3 hormone-receptor positive, HER2-negative breast cancer. In no way should the results seen in the PALLAS trial detract from our current use of CDK4/6 inhibitors in the metastatic setting. Multiple trials have shown us that these agents improve progression-free as well as overall survival in both first-line and pre-treated settings for metastatic disease. However, at this time based on the PALLAS trial, the use of palbociclib in the adjuvant setting cannot be encouraged.



Though an important detail of the PALLAS trial is that eligibility required a patient's tumor tissue block be submitted and received at a central biorepository. We also collect blood samples throughout the time on the trial. At this point in time, we have an incredible 6,000 patient tumor blocks and tens of thousands of blood samples.



There is an overarching TRANS-PALLAS program, which is designed to provide laboratory-based relative investigation and generate translational research to better understand biomarkers that will help us evaluate the experience of receiving CDK4/6 inhibitors in the adjuvant setting-- as well as, overall, how best to treat hormone-receptor positive, HER2-negative breast cancer.



There is also an arm of TRANS-PALLAS focused on clinical science, and we have collected substantial quality of life patient-reported outcomes and adherence to oral therapy data. Analysis in both arms of TRANS-PALLAS is actively ongoing, and we hope to be able to share the results from these analyses within the next one to two years. Additionally, I would like to point out that the follow-up time for the adjuvant CDK4/6 inhibitors studies is quite short. The natural history of hormone-receptor positive breast cancer is very prolonged. And personally, I think that we need more time or data from the trials to mature for us to truly comprehensively understand the impact of using CDK4/6 inhibitors in the adjuvant setting.