CDK4 selective inhibition improves preclinical anti-tumor efficacy and safety
CDK4/6 inhibitors have revolutionized treatment of hormone receptor positive (HR+), HER2 non-amplified (HER2-) breast cancer. Yet, all "dual" CDK4/6 inhibitors show common dose-limiting hematologic toxicities, foremost neutropenia. This poses challenges to provide these agents at concentrations necessary to extinguish cell cycling in tumors. HR+ breast cancer cells are highly dependent on CDK4 but not CDK6. By contrast, CDK4 is dispensable for human bone marrow derived cells, due to the primary and compensatory role of CDK6 in hematopoiesis. This prompted us to develop atirmociclib (PF-07220060), a next-generation CDK4 selective inhibitor. Atirmociclib's impact on circulating neutrophils was reduced, in proportion with its increase in CDK4 versus CDK6 selectivity. Realized dose intensification led to greater CDK4 inhibition and deeper anti-tumor responses, pointing to CDK4 target coverage as a limiting factor of CDK4/6 inhibitor efficacy. We also highlight combinatorial agents that may counter acquired resistance to CDK4 selective inhibition and widen its clinical application.
Authors
- Jing Yuan (ORCID: https://orcid.org/0000-0002-3844-5502)
- Ping Chen (ORCID: https://orcid.org/0000-0002-8504-5552)
- Lisa Nguyen (ORCID: https://orcid.org/0000-0002-9272-3980)
- Sajiv K. Nair (ORCID: https://orcid.org/0000-0002-8628-6999)
- Meirong Xu
- Tiana Dodd
- Brion W. Murray (ORCID: https://orcid.org/0000-0003-1591-2566)
- Nanni Huser
- Matthew D. Petroski
- Stephen G. Dann
- Julie Cianfrogna
- John C. Kath (ORCID: https://orcid.org/0009-0009-0685-4967)
- Lars Anders
- Aida Sacaan
- Bernadette Pascual
- Na Wei (ORCID: https://orcid.org/0000-0002-8803-3303)
- Augustine Kang
- Judith G. Deal
- Danan Li
- Britton Boras (ORCID: https://orcid.org/0000-0003-3624-9177)
- Jason Carmody (ORCID: https://orcid.org/0000-0001-6399-8646)
- Mehran Jalaie
- Rose Ann Ferre (ORCID: https://orcid.org/0000-0001-7462-1879)
- Nichol Miller
- Gary M. Gallego (ORCID: https://orcid.org/0000-0002-5665-9416)
- Todd VanArsdale
- Timothy R. Baffi (ORCID: https://orcid.org/0000-0003-2862-6155)
- Tae Sung
- James Solowiej
- Sujin Cho-Schultz
- Casey L. Quinlan (ORCID: https://orcid.org/0000-0002-7808-8271)
- Suvi T. M. Orr
- Kimberly H. Kim
- Scott J. Garza
- Zhengyan Kan (ORCID: https://orcid.org/0000-0003-4280-0850)
- Andrew R. Nager (ORCID: https://orcid.org/0000-0002-2909-9767)
- Cathy Zhang (ORCID: https://orcid.org/0000-0003-1340-8876)
- Whijae Roh (ORCID: https://orcid.org/0000-0002-7395-9939)
- Jérôme Goudeau (ORCID: https://orcid.org/0000-0002-2483-1955)
- Na Li (ORCID: https://orcid.org/0000-0001-5101-008X)
- Wade Diehl
- Qin Zhang (ORCID: https://orcid.org/0000-0002-9845-4099)
- Yanke Yu (ORCID: https://orcid.org/0000-0002-3276-0130)
- Hong Shen (ORCID: https://orcid.org/0000-0003-4852-0278)
- Elizabeth A. McMillan (ORCID: https://orcid.org/0000-0001-9891-2734)
- Cynthia L. Palmer
- Xiu Yu
- A. Gupta
- Eric W. Johnson
- Jennifer Lapira-Miller
- Seth Darensburg
- James V. Oakley
Institutions
- Pfizer (United States) (US)
- Université Bourgogne Franche-Comté (FR)
Publication Details
- Journal
- Cancer Cell
- Published
- 2025-03-01
- DOI
- https://doi.org/10.1016/j.ccell.2025.02.006
- Citations
- 39
- Primary Topic
- Advanced Breast Cancer Therapies
- Type
- article
- Field-Weighted Citation Impact
- 59.22
Funders
- Industrial Macromolecular Crystallography Association Collaborative Access Team