Abstract P1-18-29: Male patients with hormone receptor positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) receiving palbociclib in the real-world: patient characteristics, treatment patterns, and outcomes from the POLARIS study

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Abstract Background: Although male breast cancer accounts for <1% of all breast cancer diagnoses, its incidence is increasing. Palbociclib in combination with an aromatase inhibitor or fulvestrant is indicated for treating HR+/HER2- ABC in men. Adding to a previous analysis describing real-world patient characteristics and treatment patterns in men with HR+/HER2- ABC, this analysis describes additional patient characteristics, study site characteristics, and preliminary tumor response data in male patients enrolled in the POLARIS study. Methods: POLARIS is a prospective, noninterventional real-world study of patients with HR+/HER2- ABC who received palbociclib as deemed appropriate by a physician; the targeted enrollment is 1500 patients from approximately 110 US and Canadian sites. Patient and study site data were collected from the treating physicians’ routine clinical assessments (eg, patient medical charts, surveys, site questionnaires). Real-world tumor response was determined based on the treating physicians’ assessments of imaging results and clinical progression. Results: As of December 17, 2020, 15 men were enrolled across 12 US sites; most were community-based sites (75%; Table 1) and most physicians (58.3%) had been treating patients with ABC for 11-20 years. The median age of patients was 66 years, 46.7% of patients had visceral disease, and 41.7% had bone-only disease. Seven patients received palbociclib plus an aromatase inhibitor, 7 patients received palbociclib plus fulvestrant, and 1 patient received palbociclib plus tamoxifen. Two patients initiated palbociclib treatment at 100 mg due to comorbidities. Five patients had ≥1 comorbidity (ie, anemia, neutropenia, cellulitis, myocardial infarction, hypertension, neoplasm, or cerebrovascular disorder). All patients received ≥1 concomitant medications (Table 2). Medications commonly received included antihyperglycemics (53.3%), antidepressants (46.7%), opioids (40.0%), antihyperlipidemics (26.7%), and antithrombotics (26.7%). Among all 15 patients, 1 had a best tumor response of complete response (CR) and 4 patients had a partial response (PR), as reported by the physician. Among patients who received palbociclib in the first-line setting (n=9), 1 had a CR and 3 had a PR, as reported by the physician. Conclusions: These findings add to the current knowledge of the male patient population enrolled in the POLARIS study and provide preliminary information on clinical outcomes. This population represents a real-world patient cohort with a heavy disease burden. Although longer follow-up of this patient cohort is warranted, these results continue to support palbociclib as a treatment for men with HR+/HER2- ABC. Pfizer (NCT03280303). Table 1.US Study Site CharacteristicsSite characteristicSites (N=12), n (%)Geographic locationSouth8 (66.7)Midwest3 (25.0)West1 (8.3)Site categoryCommunity9 (75.0)Academic1 (8.3)Other2 (16.7)Number of treating physicians at the practice*Median (range)12 (3-30)Distribution1-104 (33.3)11-205 (41.7)21-302 (16.7)Not reported1 (8.3)Number of breast cancer cases treated annually†Median (range)350 (50, 3000)Distribution50-1502 (16.7)>1508 (66.7)Not reported2 (16.7)Number of HR+/HER2- A/MBC cases treated annually†Median (range)100 (20, 600)Distribution<503 (25.0)50-1503 (25.0)>1504 (33.3)Missing2 (16.7)Use of clinical pathwaysYes7 (58.3)No5 (41.7)A/MBC=advanced/metastatic breast cancer. *Data missing for 1 site; †data missing for 2 sites. Table 2.Documented Concomitant Medications Received in >10% of Patients*MedicationPatients (N=15), n (%)Antihyperglycemics8 (53.3)Metformin4 (26.7)Glimepiride2 (13.3)Antidepressants7 (46.7)Anxiolytics7 (46.7)Alprazolam4 (26.7)Buspirone2 (13.3)Vitamin A and D, including combinations6 (40.0)Cholecalciferol6 (40.0)Opioids6 (40.0)Procet2 (13.3)Calcium3 (20.0)Other analgesics and antipyretics6 (40.0)Paracetamol3 (20.0)Antiemetics and antinauseants5 (33.3)Prochlorperazine3 (20.0)Ondansetron2 (13.3)Antihyperlipidemics4 (26.7)Atorvastatin2 (13.3)Antithrombotics4 (26.7)Rivaroxaban2 (13.3)Peptic ulcer and GORD medications4 (26.7)Pantoprazole2 (13.3)Thyroid medications3 (20.0)Levothyroxine3 (20.0)Angiotensin II receptor blockers3 (20.0)Losartan3 (20.0)ACE inhibitors2 (13.3)Lisinopril2 (13.3)Low-ceiling diuretics, thiazides2 (13.3)Hydrochlorothiazide2 (13.3)High-ceiling diuretics2 (13.3)Furosemide2 (13.3)Vitamin B12 and folic acid2 (13.3)Cyanocobalamin2 (13.3)Hypnotics and sedatives2 (13.3)Zolpidem2 (13.3)ACE=angiotensin-converting enzyme; GORD=gastro-oesophageal reflux disease.*Specific medications received by >10% of patients; information is entered voluntarily and is subject to missing data. This list is not exhaustive. Citation Format: Joanne Blum, Caroline DiCristo, David Gordon, Meghan Karuturi, David Oubre, Erin Jepsen, Juan Cuevas, Shailendra Lakhanpal, Zhe Zhang, Yao Wang, Debu Tripathy. Male patients with hormone receptor positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) receiving palbociclib in the real-world: patient characteristics, treatment patterns, and outcomes from the POLARIS study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-18-29.