Poster Presentation Clinical Oncology Society of Australia Annual Scientific Meeting 2024

Real-world usage patterns of palbociclib and associated patient characteristics in Australia: a retrospective analysis (#374)

Richard H De Boer 1 , Louise Nott 2 , Maree Colosimo 3 , Eugene Moylan 4 , Giles W.P Stratton 5 , Thomas W Chiu 5 , Mahsa H Kouhkamari 6 , Maureen Hitschfeld 6 , Jessica Michie 5
  1. St Vincent's Private Hospital, Melbourne
  2. Icon Cancer Centre, Hobart
  3. St Vincent's Private Hospital Northside, Brisbane
  4. Liverpool Hospital, Liverpool
  5. Pfizer, Australia and New Zealand
  6. IQVIA, Australia

Objectives 

This study sought to understand the real-world use of palbociclib in HR+/HER2- advanced or metastatic breast cancer in Australia. The primary objective was to describe the demographic and clinical characteristics of patients initiating Pharmaceutical Benefits Scheme (PBS) funded palbociclib, including age, sex and baseline comorbidity burden. Secondary objectives included evaluating real-world usage and outcomes with palbociclib, including initiation dose and modifications, time to chemotherapy initiation, persistence, and subsequent use of PBS reimbursed anti-cancer medications post-discontinuation.  

Method 

This non-interventional retrospective cohort study utilised the PBS10% dataset, which includes longitudinal claims data from January 2004 to December 2023. The study population comprised CDK4/6i-naïve patients aged ≥18 years who initiated treatment with PBS funded palbociclib. Comorbidities were determined using the validated Rx-Risk Comorbidity Index. Descriptive data analyses were conducted, and Kaplan-Meier method was used for time-to event analysis. 

Results 

The study analysed data from 407 patients initiating palbociclib. Analyses identified that the median age at palbociclib initiation was 67 years, 67% were >60 years old at initiation. 67% of patients received treatment for ≥3 comorbidities in the preceding 12 months. 80% of patients started on 125 mg formulation and 53% of patients did not experience a dose modification (all initiated doses). At a median follow-up of 38 months, 61% and 40% remained on treatment at 12 and 24 months, the median time on palbociclib was 541 days (~18mo). Median time to chemotherapy was not reached. Of the patients who discontinued palbociclib during the study period, 82.6% commenced other PBS reimbursed anti-cancer medications within 180 days. Subsequent therapies included aromatase inhibitors (54%), fulvestrant (12.9%), everolimus (5.3%) and chemotherapy (54.5%) including capecitabine (32%) and nab-paclitaxel (18.7%). 

Conclusion 

This study provides real-world data on the utilisation and outcomes on palbociclib in Australia, offering insights into the management of HR+/HER2- advanced or metastatic breast cancer.