Abstract 315P
Background
POLARIS is a prospective, real-world, noninterventional study in patients with HR+/HER2‒ ABC receiving palbociclib (PAL). This report describes real-world PAL use in BIPOC, an underrepresented group in clinical trials.
Methods
POLARIS has a target enrollment of 1500 across 100 US and 10 Canadian sites (community and academic). This interim analysis reports patient demographics, clinical characteristics, treatment (tx) patterns, and safety in BIPOC using data collected from medical charts and physician surveys.
Results
Of 1280 patients treated with PAL as of November 10, 2020, 233 BIPOC were enrolled, of whom 59.2% were Black, 37.3% Hispanic, 3.4% American Indian or Alaskan Native, and 2.1% Pacific Islander. Median age was 61 years, and patients had completed ≥6 months’ tx with PAL. Patients received PAL + letrozole (LET)/anastrozole (ANA; n=116, 80% as first-line tx), PAL + fulvestrant (FUL; n=94, 72% as first-line tx), PAL + exemestane (EXE; n=13, 62% as first-line tx), or PAL + another tx (n=10, 60% as first-line tx; Table). Across tx partner subgroups, 85%−100% of patients had stage IV cancer and 31%−40% had visceral disease. Most patients initiated PAL at 125 mg regardless of tx partner. Dose modification due to adverse events (AEs) occurred in 9% of patients with PAL + LET/ANA, 6% with PAL + FUL, and 31% with PAL + EXE. Neutropenia was the most common grade ≥3 AE reported (16%, 13%, and 8%, respectively). Febrile neutropenia occurred with PAL + LET/ANA (3%) and PAL + FUL (1%). Table: 315P
Baseline characteristics
| PAL + LET/ANA (n=116) | PAL + FUL (n=94) | PAL + EXE (n=13) | PAL + Other (n=10) | |
| Age, y, mean (SD) | 60 (13) | 61 (13) | 62 (14) | 53 (12) |
| Distant metastasis sites at entry, median (range) | 2 (1−7) | 2 (1−5) | 1 (1−4) | 2 (1−4) |
| Metastases at diagnosis | ||||
| Bone + other | 41 (35) | 38 (40) | 3 (23) | 4 (40) |
| Bone only | 41 (35) | 30 (32) | 4 (31) | 3 (30) |
| Visceral disease | 42 (36) | 37 (39) | 4 (31) | 4 (40) |
| ECOG PS | ||||
| 0 | 49 (42) | 33 (35) | 7 (54) | 2 (20) |
| 1 | 45 (39) | 39 (42) | 4 (31) | 5 (50) |
| ≥2 | 10 (9) | 10 (11) | 1 (8) | 2 (20) |
| Unknown | 12 (10) | 12 (13) | 1 (8) | 1 (10) |
| Starting dose, mg | ||||
| 75 | 2 (2) | 4 (4) | 1 (8) | 1 (10) |
| 100 | 7 (6) | 8 (9) | 0 | 0 |
| 125 | 107 (92) | 82 (87) | 12 (92) | 9 (90) |
| PAL dose modification | 16 (14) | 11 (12) | 4 (31) | 0 |
n (%) unless noted. ECOG PS= Eastern Cooperative Oncology Group Performance Status.
Conclusions
PAL was routinely prescribed in clinical practice for BIPOC, with the majority of patients initiating PAL at the recommended 125-mg dose. PAL was well tolerated, with similar rates of dose modifications and AEs regardless of tx partner.
Clinical trial identification
NCT03280303.
Editorial acknowledgement
Editorial support was provided by John Teiber, PhD, of ICON plc (North Wales, PA) and was funded by Pfizer Inc.
Legal entity responsible for the study
Pfizer Inc.
Funding
Pfizer Inc.
Disclosure
G. Rocque: Financial Interests, Institutional, Research Grant: Pfizer Inc; Financial Interests, Institutional, Research Grant: Genentech; Financial Interests, Institutional, Research Grant: Carevive; Financial Interests, Institutional, Advisory Role: Pfizer Inc. J. Blum: Financial Interests, Personal, Advisory Role: Pfizer Inc; Financial Interests, Personal, Advisory Role: Amgen; Financial Interests, Personal, Advisory Role: Biotheranostics; Financial Interests, Personal, Advisory Role: Novartis; Financial Interests, Personal, Advisory Role: Genomic Health; Financial Interests, Personal, Advisory Role: Puma Biotechnology; Financial Interests, Personal, Advisory Role: Myriad; Financial Interests, Personal, Advisory Role: Immunomedics; Financial Interests, Personal, Advisory Role: Daiichi Sankyo; Financial Interests, Personal, Advisory Role: Research to Practice; Financial Interests, Personal, Advisory Role: Athenix. C. Gallagher: Financial Interests, Personal, Advisory Role: Seattle Genetics; Financial Interests, Personal, Advisory Role: Daiichi Sankyo; Financial Interests, Personal, Advisory Role: AstraZeneca. J. Cappelleri: Financial Interests, Personal, Full or part-time Employment: Pfizer Inc; Financial Interests, Personal, Stocks/Shares: Pfizer Inc. Y. Wang: Financial Interests, Personal, Full or part-time Employment: Pfizer Inc; Financial Interests, Personal, Stocks/Shares: Pfizer Inc. D. Tripathy: Financial Interests, Institutional, Research Grant: Novartis; Financial Interests, Personal, Advisory Role: Novartis; Financial Interests, Personal, Advisory Role: Pfizer. All other authors have declared no conflicts of interest.