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. 2024 Jun 20;2(1):44.
doi: 10.1038/s44276-024-00070-w.

Real-world effectiveness of CDK 4/6 inhibitors in estrogen-positive metastatic breast cancer

Mathilde Louise Gehrchen  1 , Tobias Berg  2   3 , Rasmus Garly  2 , Maj-Britt Jensen  2 , Saskia Eßer-Naumann  4 , Jeanette Dupont Rønlev  5 , Hanne Melgaard Nielsen  6 , Ann Knoop  2   3 , Iben Kümler  7   8
Affiliations

Real-world effectiveness of CDK 4/6 inhibitors in estrogen-positive metastatic breast cancer

Mathilde Louise Gehrchen et al. BJC Rep. .

Abstract

Background: Initial treatment for advanced ER-positive/HER2-negative breast cancer involves a CDK 4/6 inhibitor (CDK 4/6i). Recent overall survival (OS) analyses led the Danish Medical Council to exclude palbociclib as preferred option. This study aimed to evaluate the real-world effectiveness of abemaciclib, palbociclib, and ribociclib in a Danish context. Additionally, to compare the inhibitors to identify potential endpoint differences.

Material and methods: Patients undergoing first or second line CDK 4/6i treatments from January 1st, 2017, until December 31st, 2021 were included. The primary endpoint was progression free survival (PFS).

Results: Among 2069 Danish patients, 1554 received first line treatment, 515 received second line treatment. In first line, abemaciclib's median PFS was unreached; palbociclib had a median PFS of 32.0 months (95% CI: 28.9-35.3); ribociclib 42.4 months (95% CI: 35.1-52.9). First-line median OS was 37.8 months (95% CI: 32.5-NA); 49.7 months (95% CI: 44.7-54.1); and 54.4 months (95% CI: 47.9-NA) for abemaciclib, palbociclib and ribociclib, respectively. No significant differences in OS were observed, nor in PFS in second line.

Conclusion: This study confirms first-line CDK 4/6i effectiveness, with abemaciclib and ribociclib showing prolonged PFS vs. palbociclib. This study could not confirm a ranking of the three CDK 4/6i.

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Conflict of interest statement

MLG: Unrestricted research grant from the Danish Cancer Society. TB: Institutional grants: Pfizer, Astra Zeneca, Novartis, Samsung Bioepis, Seattle Genetics, Merck, Eli Lilly and Danish Cancer Society. Personal grants (advisory board/presentation): Merck, Astra Zeneca, Pfizer and Novartis. Personal grants (travel): Daiichi Sankyo. RG: None. MJ: Meeting expenses and advisory board, Novartis. SN: None. JDR: None. HMN: None. AK: Institutional grants from Pfizer, AstraZeneca, Merck, Eli Lilly, Seattle Genetics, Roche, Novartis. Personal grants from Astra Zeneca and Daiichi Sankyo (travel + advisory board), MSD, Novartis, Seagen (Advisory Board). IK: None.

Figures

Fig. 1
Fig. 1. Flowchart of the study cohort.
Patients were divided in subgroups based on line of treatment, type of CDK4/6i, and type of endocrine backbone.
Fig. 2
Fig. 2. Progression-free survival (PFS).
a Progression-free survival in patients receiving CDK 4/6i treatment in first line. Shaded areas represent confidence intervals. b Progression-free survival in patients receiving CDK 4/6i treatment in first line grouped by CDK 4/6i type. Shaded areas represent confidence intervals. c Progression-free survival in patients receiving CDK 4/6i treatment in second line grouped by CDK 4/6i type. Shaded areas represent confidence intervals.
Fig. 3
Fig. 3. Overall Survival (OS).
a Overall survival in patients receiving CDK 4/6i treatment in first line. Shaded areas represent confidence intervals. b Overall survival in patients receiving CDK 4/6i treatment in first line grouped by CDK 4/6i type. Shaded areas represent confidence intervals. c Overall survival in patients receiving CDK 4/6i treatment in second line grouped by CDK 4/6i type. Shaded areas represent confidence intervals.
Fig. 4
Fig. 4. Competing risk analysis of time on treatment (ToT).
The blue curve represents patients who discontinue CDK 4/6i treatment due to death of any cause. The red curve represents patients who discontinue CDK 4/6i treatment due to other reasons, i.e. progression, toxicities, and change in treatment etc.
See this image and copyright information in PMC

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