ESMO Asia Virtual Congress 2020

Abstract 56P

Background

Palbociclib has been the first and only CDK4/6 inhibitor approved for breast cancer treatment by China Food and Drug Administration since July 2018. This research concluded the clinical use of palbociclib and provided stratified analyses by indicators that have not been reported, such as weight, percentage of estrogen receptor (ER) plus progesterone receptor (PR), and time to re-biopsy.

Methods

We retrospectively analyzed data from breast cancer patients treated with palbociclib and endocrine therapy from our medical center between May 2018 and January 2020.

Results

Among 51 patients treated with palbociclib, 14 patients were treated in first-line and 37 patients in second or later lines with a median progression-free survival (PFS) of 8 months (95% CI: 5.05-10.96), while the median PFS of first-line patients has not reached. Median PFS of all groups was 10 months (95%CI: 7-13). Patients with recent immunohistochemical confirmation 6 months before had a median PFS of 8 months (95% CI: 5.24-10.79) and group with pathology in 6 months had not reached its mPFS. Non-hepatic metastatic patients had a median PFS of 11 months (95% CI: 9.00-13.00), while the hepatic metastatic ones of 3 months (95% CI: 0.95-5.05). The objective response rate (ORR) was 10.6% (5/47, 95% confidence interval [CI]: 3.5%-23.1%) and clinical benefit rate (CBR) was 67.4% (29/43, 95% CI: 51.5%-80.9%). Better clinical outcomes were associated with recent pathological confirmation of immunohistochemical analysis (P=0.046) and non-hepatic metastasis (P=0.001), but they were not related to ER/PR percentage, Ki67 index, weight, or previous chemotherapy in first/second line of palbociclib setting groups.

Conclusions

Our report indicated favorable efficacy of palbociclib in terms of recent pathological confirmation and non-hepatic metastasis, providing further information about the use of palbociclib.