The CDK4/6-inhibitor palbociclib (PBC) improves PFS when added to 1st or 2nd line endocrine therapy (ET) in hormone receptor positive (HR+) advanced breast cancer (BrC). Adding PBC in 2nd line upon progression on ET alone in 1st line rather than upfront treatment with ET+PBC results in significantly shorter duration of the use of PBC, with reduced side effects and impact on health care budgets. Although this strategy appears effective in cross-study comparisons and statistical simulations, a formal comparison of both strategies is lacking. In the absence of this formal comparison, upfront use of ET + PBC in 1st line is commonly advocated in daily practice worldwide and likely to become standard of care.
We aim to set up a nationwide, randomized phase-3 trial comparing ET + CDK4/6 in 1st line followed by ET at progression with ET alone in 1st line followed by ET + CDK4/6 at progression for advanced HR+ BrC. Primary endpoint is PFS after two lines (PFS2); secondary endpoints are cost-effectiveness, QoL and OS.
The trial is supported by the Dutch Society for Medical Oncology, the Dutch Breast Cancer Research Group and the Dutch Breast Cancer Patient Association. A total of 74 hospitals have indicated their intent to participate in the trial, guaranteeing high accrual. The study itself will be a great return on investment through a 30 million(M) euro reduction in costs for PBC use. Implementation of the trial results may lead to annual savings of about 110M euro in the Netherlands