Skip to main content
Background

KISQALI—a different CDK4/6 inhibitor

Differences among CDK4/6 inhibitors

“It is CDK4 that plays a critical role in breast cancer, cell cycle progression, and cell proliferation and…ribociclib inhibits CDK4 8 times more than CDK6…” —Dejan Juric, MD

See more medical expert perspectives

CDK4 is a key driver of HR+/HER2- mBC1

CDK4 plays a critical role in breast cancer cell cycle progression and cell proliferation1
  • Levels of CDK4 are increased in many breast tumors while levels of CDK6 are decreased2-4

  • Inhibition of CDK4 has been shown to reduce cell proliferation in breast cancer tumors1

Available drug is able to penetrate cells to bind and inhibit CDK45,6
  • Available drug is the concentration of drug that is able to reach the bloodstream for circulation

All CDK4/6 inhibitors are different

Data derived from 2 separate publications6,7
Select differences among CDK4/6 inhibitors6-10
CDK4/6 inhibition relative to CDK6 from a cellular assay

KISQALI has been shown to prolong the QT interval in a concentration-dependent manner. Please see Warning/Precaution on QT interval prolongation.1 

  • Ribociclib inhibits CDK4 up to 8x more than CDK66,7

    — Relative inhibition of CDK4 to CDK6 was reported from 2 separate publications. The relative inhibition in the cellular assay was 8.0-fold for ribociclib, 5.5-fold for abemaciclib, and 1.3-fold for palbociclib.In the biochemical assay, affinity for CDK4 vs CDK6 was 5-fold for ribociclib, 9-fold for abemaciclib, and 1-fold for palbociclib7

    — Inhibition of CDK4 relative to CDK6 in the above chart was based on a preclinical, in vitro cellular assay. The activities of ribociclib, palbociclib, and abemaciclib were tested in proliferation assays using cancer cell lines where either CDK4 or CDK6 plays a dominant role in cell cycle progression6

  • Ribociclib had high levels of drug available to bind in a pharmacokinetic analysis7-10

    — Drug available to bind was based on steady-state average unbound drug concentration at doses: ribociclib (600 mg once daily), palbociclib (125 mg once daily), and abemaciclib (200 mg twice daily). Values were normalized to palbociclib. Unbound drug exposure may not correlate with clinical outcomes

  • The information herein is not presented to compare the efficacy or safety profile of the discussed compounds. No implication of superiority or inferiority is intended or should be inferred, as the data herein do not necessarily correlate with clinical outcomes

  • This information is being shared with health care professionals to help ensure an accurate understanding of the pharmacokinetic/pharmacodynamic profiles of these products: ribociclib, palbociclib, and abemaciclib; different analyses may yield different results

  • There have been no head-to-head clinical studies among any of these products: ribociclib, palbociclib, and abemaciclib

  • This information is derived from publications for the respective products, which are based on presently available data

  • This information neither conveys, nor attempts to convey, the full benefit-risk profile of each product described. Treatment decisions are made based on a number of different factors related to the disease, patient, and potential therapy under consideration

CDK=cyclin-dependent kinase; mBC=metastatic breast cancer; PK/PD=pharmacokinetic/pharmacodynamic.

References: 1. Kisqali [prescribing information]. East Hanover, NJ: Novartis Pharmaceuticals Corp. 2. Yu Q, Sicinska E, Geng Y, et al. Requirement for CDK4 kinase function in breast cancer. Cancer Cell. 2006;9(1):23-32. doi:10.1016/j.ccr.2005.12.012 3. Grigoriadis A, Mackay A, Reis-Filho JS, et al. Establishment of the epithelial-specific transcriptome of normal and malignant human breast cells based on MPSS and array expression data. Breast Cancer Res. 2006;8(5)(additional file 4): R56. doi:10.1186/bcr1604 4. Lucas JJ, Domenico J, Gelfand EW. Cyclin-dependent kinase 6 inhibits proliferation of human mammary epithelial cells. Mol Cancer Res. 2004;2(2):105-114. 5. Musteata FM. Clinical utility of free drug monitoring. In: Dasgupta A, ed. Therapeutic Drug Monitoring: Newer Drugs and Biomarkers. Academic Press; 2012:75-101. 6. Kim S, Tiedt R, Loo A, et al. The potent and selective cyclin-dependent kinases 4 and 6 inhibitor ribociclib (LEE011) is a versatile combination partner in preclinical cancer models. Oncotarget. 2018;9(81):35226-35240. doi:10.18632/oncotarget.26215  7. Chen P, Lee NV, Hu W, et al. Spectrum and degree of CDK drug interactions predicts clinical performance. Mol Cancer Ther. 2016;15(10):2273-2281;(suppl tables). doi:10.1158/1535-7163.MCT-16-0300 8. Infante JR, Cassier PA, Gerecitano JF, et al. A phase I study of the cyclin-dependent kinase 4/6 inhibitor ribociclib (LEE011) in patients with advanced solid tumors and lymphomas. Clin Cancer Res. 2016;22(23):5696-5705. doi:10.1158/1078-0432.CCR-16-1248 9. Flaherty KT, LoRusso PM, DeMichele A, et al. Phase I, dose-escalation trial of the oral cyclin-dependent kinase 4/6 inhibitor PD 0332991, administered using a 21-day schedule in patients with advanced cancer. Clin Cancer Res. 2012;18(2):568-576. doi:10.1158/1078-0432.CCR-11-0509 10. Patnaik A, Rosen LS, Tolaney SM, et al. Efficacy and safety of abemaciclib, an inhibitor of CDK4 and CDK6, for patients with breast cancer, non-small cell lung cancer, and other solid tumors. Cancer Discov. 2016;6(7):740-753. doi:10.1158/2159-8290.CD-16-0095