Abstract PS7-19: Pre/perimenopausal (preMeno) women receiving palbociclib (PAL) for hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2–) advanced breast cancer (ABC) in a real-world setting: Treatment patterns from POLARIS
Authors: Karuturi Meghan S , Garrett Adnan , Blum Joanne L , Anderson Jay , Jepsen Erin , Pluard Timothy , Stanton Thomas , Manning Kenneth , Cappelleri Joseph C , Beery Faith , Wang Yao , Tripathy Debu 
Published: February 2021

Background: POLARIS is an ongoing, prospective, real world, noninterventional study in patients (pts) with HR+/HER2– ABC receiving PAL. This interim report describes real-world PAL use in preMeno pts. Methods: POLARIS has a targeted enrollment of 1500 pts from ~110 sites in the United States and Canada. Using patient data collected from medical charts and physician surveys, baseline demographics, clinical characteristics, and treatment patterns were analyzed descriptively in self-reported preMeno pts with ABC. Results: At the data cutoff of May 20, 2020, 1208 pts were enrolled; 134 (11.1%) from 61 sites were preMeno, of whom 14.2% completed ≥6 months of PAL treatment. Among 134 preMeno pts (74.6%) who received first-line (1L) therapy, 69.0% received PAL+letrozole (LET) or anastrozole, 28.0% PAL+fulvestrant, and 3.0% PAL+exemestane. Median disease-free interval was 39.3 (range: 0 to 236) months; median treatment-free interval was 14.8 (-3 to 134) months. Of 34 pts (25.4%) who received PAL as second or later line (≥2L), 23.8% previously received hormonal therapy, 28.6% chemotherapy, and 14.3% both. The majority of pts (96.27%) initiated PAL at 125 mg regardless of line of therapy (Table). During the first PAL treatment cycle, 2.9% of all preMeno pts, 1% of 1L pts, and 8.8% of ≥2L pts had a dose reduction; 8.2%, 9%, and 5.9%, respectively, had an interruption. Dose reductions/interruptions peaked in cycle 2 (11.9%/15.7%); 56.67% of these modifications were due to adverse events. Conclusions: PAL is routinely prescribed in clinical practice for preMeno women with HR+/HER2- ABC. The majority of preMeno pts in this real-world dataset received PAL+LET as 1L ABC treatment; PAL was primarily initiated at the recommended dose (125 mg) and was well tolerated with few dose modifications required. Clinical trial identification: Pfizer (NCT03280303)

Table.CharacteristicFirst-Line Pre/Perimenopausal Patients (n=100)Second or Later Line Pre/Perimenopausal Patients (n=34)Pre/Perimenopausal Patients (N=134)Age at study enrollment, yMedian (range)44 (22-61)42.5 (27-58)44 (22-61)Distribution, n (%)&lt;4032 (32.0)12 (35.3)44 (32.8)40–5045 (45.0)17 (50.0)62 (46.3)51–6923 (23.0)5 (14.7)28 (20.9)Race, n (%)White73 (73.0)26 (76.5)99 (73.9)Black or African American16 (16.0)4 (11.8)20 (14.9)Asian1 (1.0)1 (2.9)2 (1.5)Native Hawaiian or other Pacific Islander2 (2.0)0 (0.0)2 (1.5)American Indian or Alaska Native1 (1.0)0 (0.0)1 (0.7)Other3 (3.0)2 (5.9)5 (3.7)Not reported because of confidentiality regulations4 (4.0)1 (2.9)5 (3.7)Hispanic/Latino ethnicity, n (%)10 (10.0)3 (8.8)13 (9.7)Disease status, n (%)Visceral35 (35.0)13 (38.2)48 (35.8)Nonvisceral61 (61.0)17 (50.0)78 (58.2)Not reported4 (4.0)4 (11.8)8 (6.0)Bone metastases at mBC diagnosis, among patients with metastatic (stage IV) disease at study enrollment, n (%)Bone only40 (40)8 (23.5)48 (35.8)Bone plus other metastases32 (32)13 (38.2)45 (33.6)Disposition of patient ABC/mBC diagnosis at study at study enrollment, n (%)Recurrent from earlier stage (Stage 0-III)72 (72.0)18 (52.9)90 (67.2)De novo (Newly diagnosed Stage IV at enrollment)26 (26.0)15 (44.1)41 (30.6)Not reported2 (2.0)1 (2.9)3 (2.2)ECOG performance status at study enrollment (N, %)041 (41)15 (44.1)56 (41.8)126 (26)7 (20.6)33 (24.6)28 (8)3 (8.8)11 (8.2)32 (2)0 (0)2 (1.5)Not reported23 (23)9 (26.5)32 (23.9)Starting dose, first cycle of PAL treatment n (%)125 mg96 (96.0)33 (97.1)129 (96.3)100 mg2 (2.0)1 (2.9)3 (2.2)75 mg2 (2.0)0 (0.0)2 (1.5)Reason for first cycle starting dose &lt;125 mg, n (%)Patient preference0 (0.0)1 (100)1 (25.0)Other3 (100)0 (0.0)3 (75.0)

Citation Format: Meghan S Karuturi, Adnan Garrett, Joanne L Blum, Jay Anderson, Erin Jepsen, Timothy Pluard, Thomas Stanton, Kenneth Manning, Joseph C Cappelleri, Faith Beery, Yao Wang, Debu Tripathy. Pre/perimenopausal (preMeno) women receiving palbociclib (PAL) for hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2–) advanced breast cancer (ABC) in a real-world setting: Treatment patterns from POLARIS [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS7-19.