Choice of Chemotherapy after CDK4/6 Inhibition in Breast Cancer Patients Reveals Little Impact on Progression-Free Survival and Overall Survival

Strategic Insights -

Researchers at Universitatsklinikum Erlangen, in collaboration with various international institutions, have conducted a study to investigate the prognostic impact of the choice of chemotherapy after first-line CDK4/6 inhibitor therapy in patients with metastatic hormone receptor-positive, HER2-negative breast cancer. The study, published in the European Journal of Cancer, analyzed data from 215 patients who received first-line CDK4/6 inhibitor therapy and then progressed to second-line chemotherapy. The researchers found that the choice of chemotherapy did not significantly affect progression-free survival (PFS) or overall survival (OS), although combinations with bevacizumab may have shown some benefit.

Key Takeaways:

  • The study involved 215 patients who received first-line CDK4/6 inhibitor therapy and then progressed to second-line chemotherapy, with 62.3% having high-grade tumors and 73.8% developing metastatic disease following a primary breast cancer diagnosis.
  • The most common regimen used was capecitabine (25.1%), followed by taxane + bevacizumab (17.2%).
  • When adjusting for other prognostic factors, the choice of chemotherapy did not influence PFS (p = 0.16) nor OS (p = 0.47).
  • Adjusted hazard ratios for PFS were lowest in regimens with bevacizumab, with capecitabine as reference.
  • The study suggests that the side effects of chemotherapy may be more important than the choice of regimen when making treatment decisions.
  • The research has been peer-reviewed and published in the European Journal of Cancer.

Statistics:

  • 62.3% of patients had high-grade tumors.
  • 73.8% of patients developed metastatic disease following a primary breast cancer diagnosis.
  • 62.3% of patients had visceral metastases.
  • 25.1% of patients received capecitabine as their second-line chemotherapy regimen.
  • 17.2% of patients received taxane + bevacizumab as their second-line chemotherapy regimen.
  • The choice of chemotherapy did not significantly affect PFS (p = 0.16) or OS (p = 0.47).
  • Adjusted hazard ratios for PFS with capecitabine + bevacizumab were 0.53 (95% CI: 0.29, 0.97).
  • Adjusted hazard ratios for PFS with taxane + bevacizumab were 0.64 (95% CI: 0.35, 1.15).

Sources:

  • Prognostic impact of the choice of chemotherapy after first-line CDK4/6 inhibitor therapy in patients with metastatic hormone receptor-positive, HER2-negative breast cancer. European Journal of Cancer, 2025;227:115689.
  • Universitatsklinikum Erlangen, Dept. of Gynecology and Obstetrics, Friedrich-Alexander-Universitat Erlangen-Nurnberg (FAU), Erlangen, Germany.