Abstract 251P
Background
Palbociclib (PAL), a CDK4/6 inhibitor, is approved for the treatment of hormone receptor–positive/human epidermal growth factor receptor 2–negative (HR+/HER2–) advanced breast cancer (ABC). This analysis describes real-world characteristics, treatment (tx) patterns, and clinical outcomes of pts with ABC on PAL + ET.
Methods
POLARIS is a prospective, observational, multicentre real-world study of pts with HR+/HER2‒ ABC treated with PAL + ET. Real-world response rate (rwRR) is the proportion of pts with a physician-assessed best response (BR) of complete response (CR) or partial response (PR). Real-world clinical benefit rate (rwCBR) is the proportion of pts with physician-assessed BR of CR or PR at any time or stable disease for at least 24 weeks from the regimen start date. Real-world progression-free survival (rwPFS) is the time (months [mo]) from PAL + ET start to the physician-documented progression or death due to any cause, whichever occurs first. Overall survival (OS) is the time (mo) from PAL + ET start to date of death due to any cause.
Results
As of Mar 30, 2022, 1242 pts were treated with PAL + ET. Pt demographics and baseline characteristics are shown in the Table. PAL + ET was initiated as first-line (1L) ABC tx in 902 pts and as second-line or later (≥2L) in 340 pts. After a median follow-up 37.9 mo, median rwPFS (95% CI) was 32.2 mo (29.4–35.1) and 24.2 mo (19.9–30.1) in the 1L and ≥2L settings, respectively. The rwRR/rwCBR were 33.0%/67.7% in the 1L and 21.5%/57.5% in the ≥2L setting. After a median follow-up of 35.7 mo, median OS (95% CI) was 50.8 mo (42.3–65.4) and 40.0 mo (32.2–43.1) in the 1L and ≥2L settings, respectively. Table: 251P
| N=1242 | |
| Age, y | |
| Median (range) | 64 (22–97) |
| Race | |
| White | 1,019 (82.0) |
| Black | 138 (11.1) |
| Other | 22 (1.8) |
| Asian | 20 (1.6) |
| American Indian/Alaska Native | 8 (0.6) |
| Native Hawaiian/other Pacific Islander | 5 (0.4) |
| Ethnicity | |
| Not Hispanic/Latino | 1,101 (88.6) |
| Hispanic/Latino | 104 (8.4) |
| Disposition of diagnosis* | |
| Recurrent from earlier stage, stages 0–III | 843 (67.9) |
| De novo, newly diagnosed stage IV* | 340 (27.4) |
| Sites of metastases, number | |
| Median (range) | 2.0 (1, 10) |
| Bone involvement*† | |
| Bone + other metastases | 476 (40.4) |
| Bone-only | 404 (34.3) |
| Visceral disease*‡ | |
| No | 756 (60.9) |
| Yes | 486 (39.1) |
Data are n (%) unless otherwise stated *At baseline (bl) †In pts with metastasis at bl (N=1177) ‡Metastases of brain, liver, or lung/pleura
Conclusions
Results from this large prospective, real-world study are consistent with clinical trial results and support the use of PAL + ET for the treatment of HR+/HER2– ABC.
Clinical trial identification
NCT03280303.
Editorial acknowledgement
Editorial support was provided by Sonia Mohinta, PhD, of ICON plc (Blue Bell, PA, USA) and was funded by Pfizer Inc. Funded by Pfizer Inc.
Legal entity responsible for the study
Pfizer.
Funding
Pfizer.
Disclosure
D. Tripathy: Financial Interests, Personal, Invited Speaker: GlaxoSmithKline, AstraZeneca, Gilead, OncoPep; Financial Interests, Institutional, Other, Contracted research: Pfizer, Novartis. G. Rocque: Financial Interests, Personal, Advisory Role: Pfizer, Flatiron, Genentech; Financial Interests, Institutional, Other, Research grant: Pfizer, Genentech, Carevive. J.L. Blum: Financial Interests, Personal, Advisory Role: Pfizer, Amgen, Biotheranostics, Novartis, Genomic Health, Puma Biotechnology, Myriad Genetics, Immunomedics, Daiichi Sankyo, Research to Practice, Athenix. M.S. Karuturi: Financial Interests, Personal, Advisory Role: Pfizer. E. Gauthier: Financial Interests, Personal, Other, Employment: Pfizer; Financial Interests, Personal, Stocks/Shares: Pfizer. Z. Zhang: Financial Interests, Personal, Other, Employee: Pfizer; Financial Interests, Personal, Stocks/Shares: 858-626-6081. Y. Wang: Financial Interests, Personal, Other, Employment: Pfizer; Financial Interests, Personal, Stocks/Shares: Pfizer. All other authors have declared no conflicts of interest.