Poster Presentation Clinical Oncology Society of Australia Annual Scientific Meeting 2022

CDK4/6 Inhibitors (CKD4/6i) in advanced Hormone-Receptor-Positive (HR+) HER2-Negative (HER2-) breast cancer: prescribing practices and outcomes in a real-world, Australian cohort (#211)

Anadil Javaid 1 , Sheau Wen Lok 2 , Vanessa Wong 2 3 , Sally Baron-Hay 4 , Fran Boyle 5 , Ian Collins 6 , Katharine Cuff 7 , Richard de Boer 8 , Lucy Gately 9 , Chloe Georgiou 10 , Sally Greenberg 11 , Bhaskar Karki 12 , Michelle Nottage 13 , Natalie Rainey 14 , Javier Torres 15 , Belinda Yeo 16 , Bianca Devitt 1 17 , Peter Gibbs 2 , Angelyn Anton 1 17
  1. Eastern Health, Melbourne, Victoria
  2. Personalised Oncology Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria
  3. Ballarat Health Services, Ballarat, Victoria
  4. Northern Cancer Institute, Sydney, New South Wales
  5. Mater North Sydney Hospital, Sydney, New South Wales
  6. South West HealthCare, Warrnambool, Victoria
  7. Princess Alexandra Hospital, Brisbane, Queensland
  8. St Vincent’s Private Hospital, Melbourne, Victoria
  9. Alfred Hospital, Melbourne, Victoria
  10. Bendigo Health, Bendigo, Victoria
  11. Western Health, Melbourne, Victoria
  12. Toowoomba Hospital, Toowoomba, Queensland
  13. Royal Brisbane and Women’s Hospital, Brisbane, Queensland
  14. Cairns Hospital, Cairns, Queensland
  15. Goulburn Valley Health, Shepparton, Victoria
  16. Austin Health, Melbourne, Victoria
  17. Eastern Clinical Research Unit, Monash University, Melbourne, Victoria

Aims: To examine treatment trends, efficacy and toxicity in advanced HR+/HER2- breast cancer in a real-world, Australian cohort.

 

Methods: Data was extracted from the Advanced Hormone Receptor Positive Breast Cancer Registry in Australia (ARORA), a prospective registry, including 15 sites.  Patients had inoperable or metastatic HR+/HER2- breast cancer diagnosed after January 1st 2020. Patient and disease characteristics, treatment, progression-free survival (PFS) and adverse events (AEs) were extracted. Data analysis used descriptive statistics. This Research Collaboration was supported by Novartis.

 

Results: 201 patients were enrolled; 6 were excluded due to incomplete data;  median age  63 years (29-89 years); median follow-up 12.8 months. 67 (34%) had de novo metastatic disease. Of 128 patients with relapsed disease, 107 (84%) received adjuvant therapy, 98 (77%) endocrine therapy (ET) and 69 (54%) chemotherapy. 17 (13%) received no adjuvant therapy. 4 (3%) were unknown. 147 (75%) received CDK4/6i+ET in the first-line metastatic setting,  25 (13%) received ET alone, 13 (7%) received chemotherapy and 9 (5%) received no treatment.  In the CDK4/6i+ET group, 83 (56%) received palbociclib, 58 (39%) ribociclib and 12 (8%) abemaciclib. CDK4/6i was combined with an aromatase inhibitor in 121 (82%) and with fulvestrant in 27 (18%). 67 (46%) in the CDK4/6i+ET group had visceral metastases, compared to 9 (69%) in the chemotherapy group. At reporting, 55 (27%) had progressed on first-line treatment; of these 43% had relapsed on or within 6 months of adjuvant ET and 27% had de novo metastatic disease.  12-month PFS was 83% for CDK4/6i+ET. PFS and OS data is immature. The most common AEs associated with CDK4/6i+ET were neutropenia (27%), nausea/vomiting (14%) and diarrhoea (5%).

 

Conclusions: Real-world Australian data of advanced HR+/HER2- breast cancer demonstrates significant uptake of CDK4/6i+ET in the first-line setting. Toxicity is consistent with previous reports. Longer follow up will allow analysis of efficacy and subgroups.