The impact of dose delays and reductions on progression free survival (PFS) in older patients with metastatic breast cancer receiving palbocilib

Palbociclib in Older Patients with Advanced/Metastatic Breast Cancer: A Systematic Review

“…Three retrospective studies using data from the Flatiron Health longitudinal database had different study time frames and populations (in terms of patient age); however, there remains a possibility of patient overlap across studies [ 35 , 37 , 52 ]. Older patients were defined as ≥ 60 years of age in one study [ 40 ], ≥ 65 years in 21 studies [ 30 , 32 , 34 , 36 – 39 , 42 , 43 , 45 , 46 , 49 , 50 , 52 , 53 , 56 – 58 , 64 , 65 , 68 ], ≥ 70 years in 11 studies [ 31 , 44 , 47 , 48 , 54 , 55 , 59 – 63 , 66 , 67 ], and ≥ 75 years in four studies [ 33 , 35 , 41 , 51 ]. Three studies evaluated CDK 4/6 inhibitors as a class; however, ≥ 80% of the patients received palbociclib as the CDK 4/6 inhibitor [ 43 , 58 , 67 ].…”

“…Dose reduction data for older patients who received palbociclib were reported in 13 RWE studies. Of these studies, seven compared data between older and younger patients [ 32 , 34 , 39 , 40 , 44 , 50 , 67 ]. In five studies, older patients in comparison with younger patients had a higher rate of dose reductions with no detrimental effect on survival outcomes [ 32 , 39 , 44 , 50 , 67 ].…”

“…Of these studies, seven compared data between older and younger patients [ 32 , 34 , 39 , 40 , 44 , 50 , 67 ]. In five studies, older patients in comparison with younger patients had a higher rate of dose reductions with no detrimental effect on survival outcomes [ 32 , 39 , 44 , 50 , 67 ]. In a study evaluating the impact of palbociclib dose reductions on rwPFS, 38% of older patients (≥ 65 years) and 31% of younger patients (< 65 years) had dose reductions; however, rwPFS was not inferior in patients whose dose was reduced versus those whose dose was not reduced in either age group [ 32 ].…”

“…In five studies, older patients in comparison with younger patients had a higher rate of dose reductions with no detrimental effect on survival outcomes [ 32 , 39 , 44 , 50 , 67 ]. In a study evaluating the impact of palbociclib dose reductions on rwPFS, 38% of older patients (≥ 65 years) and 31% of younger patients (< 65 years) had dose reductions; however, rwPFS was not inferior in patients whose dose was reduced versus those whose dose was not reduced in either age group [ 32 ]. In a study that retrospectively examined toxicities and outcomes of older patients receiving palbociclib, the number of dose reductions was significantly higher in patients aged ≥ 65 years versus < 65 years ( P < 0.05) and in patients aged ≥ 70 years versus < 70 years ( P < 0.0001) [ 39 ].…”

“…Data for palbociclib dose delays in older patients who received palbociclib were reported in six RWE studies. Of these studies, four compared data between older and younger patients [ 32 , 39 , 50 , 67 ]. In a study assessing clinical outcomes in patients receiving palbociclib plus ET, dose delays were seen in 4% of older patients (> 65 years) and 1% of younger patients (≤ 65 years); the effectiveness (ORR, rwPFS, and OS) of palbociclib plus ET did not depend on age [ 50 ].…”