Clinical Trial

. 2025 Jun;211(2):385-397.

doi: 10.1007/s10549-025-07653-2. Epub 2025 Mar 27.

Impact of adding palbociclib on treatment adherence to ongoing adjuvant endocrine treatment in the global randomized PALLAS randomized trial in patients with early breast cancer

Eileen Shinn¹, David Zahrieh², Angela DeMichele³, Nick Zdenkowski⁴, Julie Lemieux⁵, Jun Mao⁶, Vesna Bjelic-Radisic^{7

8}, Michelle J Naughton⁹, Georg Pfeiler^{10

11}, Karen Gelmon¹², Justin M Balko¹³, Daniel Egle^{14

11}, Gabriele Zoppoli¹⁵, Tiffany Traina⁶, Miguel Martin Jimenez¹⁶, Silvia Antolin Novoa¹⁷, Tufia Haddad², Arlene Chan¹⁸, Alistair Ring¹⁹, Antonio Wolff²⁰, William Fraser Symmans²¹, Jose Ponce Lorenzo^{16

22}, Dhanusha Sabanathan²³, Hal J Burstein²⁴, Zbigniew Ireneusz Nowecki²⁵, Gunda Pristauz-Telsnigg^{8

11}, Adam Brufsky²⁶, Meritxell Bellet-Ezquerra²⁷, Theodoros Foukakis²⁸, Yelena Novik²⁹, Gabor Rubovszky³⁰, Christian F Singer^{10

11}, Karoline Muehlbacher¹¹, Otto Metzger Filho²⁴, Theodora Goulioti³¹, Ernest Law³², Ann H Partridge²⁴, Lisa A Carey³³, Alex Zoroufy², Dominik Hlauschek¹¹, Christian Fesl¹¹, Erica L Mayer^#²⁴, Michael Gnant^#^{11

34}

Affiliations

¹ The University of Texas MD Anderson Cancer Center, Houston, TX, USA. eshinn@mdanderson.org.
² Mayo Clinic, Rochester, MN, USA.
³ ECOG, University of Pennsylvania, Philadelphia, PA, USA.
⁴ The University of Newcastle, Callaghan, NSW, Australia.
⁵ Centre Hospitalier Universitaire de Québec-Université Laval, Quebec, Canada.
⁶ Memorial Sloan Kettering Cancer Center, New York, NY, USA.
⁷ Helios University Clinic Wuppertal, University Witten/Herdecke Germany, Wuppertal, Germany.
⁸ Medical University of Graz, Graz, Austria.
⁹ Ohio State University/Alliance, Columbus, OH, USA.
¹⁰ Department of Obstetrics and Gynecology, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria.
¹¹ Austrian Breast and Colorectal Cancer Study Group AT, Vienna, Austria.
¹² University of British Columbia, Vancouver, BC, Canada.
¹³ Vanderbilt University Medical Center, Nashville, TN, USA.
¹⁴ Medical University of Innsbruck, Innsbruck, Austria.
¹⁵ Gruppo Oncologico Italiano di Ricerca Clinica (GOIRC), Policlinico San Martino IRCCS, University of Genoa, Genoa, Italy.
¹⁶ GEICAM, Hospital General Universitario Gregorio Marañón, Universidad Complutense, Madrid, Spain.
¹⁷ A Coruña University Hospital, A Coruna, Spain.
¹⁸ Breast Cancer Research Centre, Nedlands, WA, Australia.
¹⁹ The Royal Marsden Hospital, NHS Foundation Trust, East Sussex, UK.
²⁰ Johns Hopkins University/ECOG, Baltimore, MD, USA.
²¹ The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
²² Oncology Department, Dr. Balmis General University Hospital, Alicante Institute for Health and Biomedical Research (ISABIAL), Alicante, Spain.
²³ Lakeside Specialist Breast Clinic, Nepean Cancer Care Centre, Norwest, NSW, Australia.
²⁴ Dana-Farber Cancer Institute, Boston, MA, USA.
²⁵ The Maria Sklodowska Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland.
²⁶ University of Pittsburgh Cancer Institute UPMC Hillman Cancer Center, Pittsburgh, PA, USA.
²⁷ Vall d'Hebron Institute of Oncology, Barcelona, Spain.
²⁸ Karolinska Institute and University Hospital, Solna, Sweden.
²⁹ New York University, New York, NY, USA.
³⁰ National Institute of Oncology, Budapest, Hungary.
³¹ Breast International Group, Brussels, Belgium.
³² Pfizer, Chicago, IL, USA.
³³ University of North Carolina/Alliance, Chapel Hill, NC, USA.
³⁴ Medical University of Vienna AT, Vienna, Austria.

^# Contributed equally.

PMID: 40140172
DOI: 10.1007/s10549-025-07653-2

Clinical Trial

Impact of adding palbociclib on treatment adherence to ongoing adjuvant endocrine treatment in the global randomized PALLAS randomized trial in patients with early breast cancer

Eileen Shinn et al. Breast Cancer Res Treat. 2025 Jun.

. 2025 Jun;211(2):385-397.

doi: 10.1007/s10549-025-07653-2. Epub 2025 Mar 27.

Authors

Affiliations

¹ The University of Texas MD Anderson Cancer Center, Houston, TX, USA. eshinn@mdanderson.org.
² Mayo Clinic, Rochester, MN, USA.
³ ECOG, University of Pennsylvania, Philadelphia, PA, USA.
⁴ The University of Newcastle, Callaghan, NSW, Australia.
⁵ Centre Hospitalier Universitaire de Québec-Université Laval, Quebec, Canada.
⁶ Memorial Sloan Kettering Cancer Center, New York, NY, USA.
⁷ Helios University Clinic Wuppertal, University Witten/Herdecke Germany, Wuppertal, Germany.
⁸ Medical University of Graz, Graz, Austria.
⁹ Ohio State University/Alliance, Columbus, OH, USA.
¹⁰ Department of Obstetrics and Gynecology, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria.
¹¹ Austrian Breast and Colorectal Cancer Study Group AT, Vienna, Austria.
¹² University of British Columbia, Vancouver, BC, Canada.
¹³ Vanderbilt University Medical Center, Nashville, TN, USA.
¹⁴ Medical University of Innsbruck, Innsbruck, Austria.
¹⁵ Gruppo Oncologico Italiano di Ricerca Clinica (GOIRC), Policlinico San Martino IRCCS, University of Genoa, Genoa, Italy.
¹⁶ GEICAM, Hospital General Universitario Gregorio Marañón, Universidad Complutense, Madrid, Spain.
¹⁷ A Coruña University Hospital, A Coruna, Spain.
¹⁸ Breast Cancer Research Centre, Nedlands, WA, Australia.
¹⁹ The Royal Marsden Hospital, NHS Foundation Trust, East Sussex, UK.
²⁰ Johns Hopkins University/ECOG, Baltimore, MD, USA.
²¹ The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
²² Oncology Department, Dr. Balmis General University Hospital, Alicante Institute for Health and Biomedical Research (ISABIAL), Alicante, Spain.
²³ Lakeside Specialist Breast Clinic, Nepean Cancer Care Centre, Norwest, NSW, Australia.
²⁴ Dana-Farber Cancer Institute, Boston, MA, USA.
²⁵ The Maria Sklodowska Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland.
²⁶ University of Pittsburgh Cancer Institute UPMC Hillman Cancer Center, Pittsburgh, PA, USA.
²⁷ Vall d'Hebron Institute of Oncology, Barcelona, Spain.
²⁸ Karolinska Institute and University Hospital, Solna, Sweden.
²⁹ New York University, New York, NY, USA.
³⁰ National Institute of Oncology, Budapest, Hungary.
³¹ Breast International Group, Brussels, Belgium.
³² Pfizer, Chicago, IL, USA.
³³ University of North Carolina/Alliance, Chapel Hill, NC, USA.
³⁴ Medical University of Vienna AT, Vienna, Austria.

^# Contributed equally.

PMID: 40140172
DOI: 10.1007/s10549-025-07653-2

Abstract

Purpose: Using patient-reported outcomes (PROs) and more objective measures, we evaluated adherence to adjuvant palbociclib and ET in the PALLAS trial, and the impact of palbociclib on ET adherence.

Methods: The open-label, global, phase 3 PALLAS trial randomized patients with hormone receptor-positive (HR+), HER2-negative stage II-III breast cancer (1:1) to either 26 cycles of palbociclib (125 mg/day for 21 days and then 7 days off) plus adjuvant ET, versus ET alone. After 23.7 months median follow-up, palbociclib was stopped due to futility of the intervention and patients were moved to follow-up. For each cycle, daily adherence to ET was measured with study diaries; for palbociclib, study diaries and pill counts. At cycles 2, 3, 6, 12, 18 and 24, patients completed the Morisky Medication Adherence Scale-4 plus an additional item and the McHorney Adherence Questionnaire. Mean persistence was defined in months from treatment initiation to cessation.

Results: Four thousand six hundred eighty-eight of 5796 total PALLAS participants were included. Across all cycles, mean daily ET adherence values measured by study diary were > 98.0% and did not differ between treatment arms. Mean persistence to ET was similar between arms (19.2 months for palbociclib + ET vs. 19.6 months for ET alone). However, patient-reported maximal ET adherence was higher across time for palbociclib + ET compared to ET alone (p ≤ 0.0001, modified MMAS-4; p = 0.05, McHorney).

Conclusion: In the PALLAS trial, addition of palbociclib did not decrease adherence to adjuvant ET. Though numbers declined over time, daily adherence for palbociclib and ET remained relatively high at each cycle.

Trial registration: The trial is registered with ClinicalTrials.gov (NCT02513394; 07-31-2015) and EudraCT (2014-005181-30).

Keywords: Adherence; Adjuvant endocrine therapy; PALLAS; Palbociclib; Patient-reported outcomes.

PubMed Disclaimer

Conflict of interest statement

Declarations. Competing interests: ADM reports institutional research support from Pfizer (Inst), Genetech (Inst), Novartis (Inst), NeoGenomics (Inst); honoraria from Fox Chase Cancer Center SABCS review 2024, Fox Chase Cancer Center SABCS review 2023, 3rd Annual Perspectives in Breast Cancer Care-Medscape 2023, 21st Annual International Congress on the Future of Breast Cancer® West San Deigo 2022, OncLive Institutional Perspectives in Cancer: Breast Cancer 2022, University Of Kanas City Post San Antonio Review 2022, ASCO 2021 Breast Cancer Highlights 2021. NZ reports honoraria from Lilly, Gilead, Pfizer, Eisai, AstraZeneca, Novartis; travel support for educational meeting attendance from Pfizer, Lilly and Novartis; participation on Advisory board for DMC; leadership for Scientific Advisory Committee Chair. JLreports honoraria from Novartis, Eli Lilly, Merck, Astra Zeneca, Daiichi Sanko, Exact Science, Gilead. GP reports research funding from Amgen, Roche,Accord, Lilly, Novartis, Seagen, Gilead, Daiichi, Menarini, Pfizer, MSD, Merck; honoraria from Amgen, Roche, Accord, Pfizer, Lilly, Merck, Daiichi, Menarini, Novartis, Seagen, MSD, and Gilead; consulting for Pfizer, Amgen, Lilly, Novartis, Merck, Daiichi, Roche, Gilead, MSD, Menarini, and Seagen; payment for expert testimony from Amgen, Roche,Accord, Lilly, Novartis, Seagen, Gilead, Daiichi, Menarini, Pfizer, MSD, Merck; travel support from Amgen, Roche,Accord, Lilly, Novartis, Seagen, Gilead, Daiichi, Menarini, Pfizer, MSD, Merck. KG reports honoraria from Eli Lilly, Pfizer, Novartis; participation in an advisory board for Eli Lilly, Pfizer, Novartis. DE reports honoraria from AstraZeneca, Daiichi-Sankyo, Gilead, Lilly, MSD, Menarini, Novartis, Pfizer, Roche, Seagen, Sirius Medical; Support for attending meetings/travel from AstraZeneca, Daiichi-Sankyo, Pfizer, Roche; participation on an advisory board for AstraZeneca, Daiichi-Sankyo, Gilead, Lilly, MSD, Menarini, Novartis, Pfizer, Roche, Seagen, Sirius Medical. GZ reports a leadership role in Immunomica S.r.l. TT reports research funding from Pfizer, AstraZeneca, Astellas Pharma, Genentech/Roche, Daiichi Sankyo, and Ayala Pharmaceuticals; consulting fees from Genentech/Roche, Pfizer, AstraZeneca, Merck, Daiichi Sankyo, Gilead Sciences, Novartis, GlaxoSmithKline, GE Healthcare, bioTheranostics, Hengrui Pharmaceuticals, G1 Therapeutics, Tersera, Stemline Therapeutics, Exact Sciences; participation on an advisory board for Genentech/Roche, I-SPY; and leadership for ASCO Breast Cancer Guideline Advisory Group (Co-Chair) and Chemo Foundation Symposium (Co-Chair). MMJ reports consulting fees from AstraZeneca, Lilly, MSD, Novartis, and Pfizer; honoraria from AstraZeneca, MSD, and Lilly. TH reports research funding from Takeda Onocolgy and consulting for Puma Biotechnology (Inst). AC reports honoraria from Olema Steering Committee; support for attendance/travel from San Antonio Breast Cancer Symposium by Olema; and leadership as Vice Chair for Breast Cancer Research Centre. AER reports consulting fees from Lilly, Seagen, and Gilead; honoraria from Pfizer, Lilly, Novartis, AZ/Daiichi-Sankyo, MSD, and Zuellig Pharma. AW reports research funding from Genentech (Inst), Merck Sharp & Dohme (Inst), Array BioPharma (Inst); he has been named as inventor on one or more issued patents or pending patent applications relating to methylation in breast cancer, and has assigned his rights to Johns Hopkins University (JHU), and participates in a royalty sharing agreement with JHU. WFS reports patent planned/issued/pending for genomic predictor of sensitivity to endocrine therapy for breast cancer and stock in Delphi Diagnostics. JJPL reports honoraria from Seattle Genetics, Novartis, Pfizer, AstraZeneca/ Daiichi Sankyo, Lilly, and Roche; advisory roles with Seattle Genetics, Novartis, AstraZeneca/ Daiichi Sankyo, Pierre Fabre, and Roche. DS reports honoraria from MSD, AZ, Gilead; participation on a Data Safety Monitoring Board for MSD. AB reports consulting fees from Astrazeneca, Pfizer, Novartis, Lilly, Genentech/Roche, SeaGen, Daiichi Sankyo, Merck, Agendia, Sanofi, Puma, Myriad, Gilead. MB-E reports personal fees from Pfizer, Novartis, and Lilly, outside the submitted work; and travel expenses from Pfizer and Roche. TF reports research support from Pfizer (Inst), AstraZeneca (Inst), Novartis (Inst), and Veracyte; royalties/licenses from UpToDate; consulting fees from Affibody; honoraria from Gilead, Pfizer, Roche, AstraZeneca; receipt for equipment/material/drugs/i.e. from AstraZeneca, Novartis, Veracyte, and Pfizer. YN reports honoraria from Novartis, Radius/Stemline, Astellas. GR reports consulting fees from Roche, Lilly, Pfizer, Novartis, Swixx, and AstraZeneca; honoraria from Novartis and Roche; support for attending meetings/travel from Swizz, Pfizer, and Roche. CFS reports grants and honoraria by Amgen, Daiichi Sankyo, Eli Lilly, Novartis, AstraZeneca, Pfizer, Roche, Seagen, Gilead, MSD. KM reports funding of study and partial support of salary from Pfizer. OM reports research funding from Pfizer; consulting fees from Grupo Oncoclinicas (Brazil); honoraria from Astra Zeneca, Merck, and Sanofi. TG reports research support from Pfizer. EL is employed by and a stockholder of Pfizer. AHP reports royalties from UpToDate Royalties. LAC reports other uncompensated financial/nonfinancial interests from Lilly, Seattle Genetics, Novartis, Genentech/Roche, and GSK. DH reports funding of study and partial support of salary from Pfizer. CF reports funding of study and partial support of salary from Pfizer. ELM reports a consulting role with Lilly, Novartis, AstraZeneca and Gilead. MG reports funding of study from Pfizer; consulting fees from EPG Health and MSD; honoraria from Amgen, AstraZeneca, Daiichi Sankyo, Eli Lilly, Menarini, Novartis, Pierre Fabre; payment for expert testimony from Eli Lilly and Veracyte; non-paid participation on an advisory board for ATNEC trial; and leadership in ABCSG. The remaining authors declare no competing interests. Ethical approval: This study was conducted in line with the principles of the Declaration of Helsinki. The research protocol was approved by local or central institutional boards or ethics committees. The trial was monitored throughout by an international independent data monitoring committee. Patients provided written informed consent before participating in the study.

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Impact of adding palbociclib on treatment adherence to ongoing adjuvant endocrine treatment in the global randomized PALLAS randomized trial in patients with early breast cancer

Affiliations

Impact of adding palbociclib on treatment adherence to ongoing adjuvant endocrine treatment in the global randomized PALLAS randomized trial in patients with early breast cancer

Authors

Affiliations

Abstract

Conflict of interest statement

References

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Substances

Associated data

Grants and funding

LinkOut - more resources

Full Text Sources

Medical

Research Materials

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