Abstract 1519
Background
Following the approval of palbociclib as the first CDK4/6 inhibitor for HR+/HER2- advanced/metastatic breast cancer (ABC/ MBC), a need exists to understand treatment patterns associated with palbociclib combination therapies in real world clinical settings. The Ibrance Real World Insights (IRIS) study aims to address this evidence gap.
Methods
A retrospective chart review of HR+/HER2- ABC/ MBC patients who received palbociclib combination therapies was conducted in Germany. Physicians completed electronic case report forms (eCFRs), extracting data on patient demographics, clinical characteristics and treatment patterns from an index date (60 days after physician’s first prescription of palbociclib) until the most recent record available.
Results
42 physicians completed 257 eCRFs with 48% representing academic centers. The mean (SD) age of patients at palbociclib initiation was 59.6 (9.4) years (median, 60 years). ECOG status at palbociclib initiation was mostly 0 (48.2%) or 1 (33.5%). Visceral disease was present in 65.6% of patients. Approximately 75% of patients received palbociclib in combination with aromatase inhibitors (AI) and 25% in combination with fulvestrant. Overall, 97% patients received palbociclib + AI as 1st line advanced therapy, the remaining having received chemotherapy previously in the advanced setting. Letrozole was the most common AI partner therapy (63.4%) followed by anastrozole (23.2%), and exemestane (13.4%). Palbociclib + fulvestrant was mostly used in first (44.4%) and second (52.4%) lines. The most frequently prescribed starting dose was 125 mg/day (73.2%), followed by 100mg/day (26.1%) and 75 mg/day (0.8%). 76% of palbociclib + AI patients started on 125 mg compared to 65% of palbociclib + fulvestrant patients. Dose reductions occurred in only 28 (10.9%) patients (7.4% of those who started at 125 mg/day) and a cycle delay occurred in 1 (3.4%) patient. Dose reduction rates were 10.8% in palbociclib + AI and 11.1% in palbociclib + fulvestrant.
Conclusions
In the real world setting, rates of dose reduction were low, and were similar between palbociclib + AI and palbociclib + fulvestrant in HR+/HER2- ABC/ MBC patients in Germany.
Clinical trial identification
Legal entity responsible for the study
Pfizer Inc.
Funding
Pfizer Inc.
Editorial Acknowledgement
Disclosure
D. Mitra: Employment and stock ownership: Pfizer. G. Taylor-Stokes, J. Waller, K. Gibson, G. Milligan: Employee: Adelphi Real World, who were paid consultants to Pfizer in connection with the development of this abstract. S. Iyer: Employment and stock ownership at Pfizer.