Statistical analysis
toxicity, death, tumors
DISEASE, TUMORS
Sample size was obtained with Simon’s two-stage design for the primary endpoint of a 6-month progression-free survival rate, and estimated accrual of 24 months. The initial design estimated a 6-m PFSR of 14%, the EORTC cut-off for second-line active drugs,An amendment was approved increasing the delta value between H0 and H1 due to a slower accrual related, in particular due to the COVID pandemic. In the new design, the type I and II errors (10%) remained unchanged, but the null hypothesis (H0) was increased up to 15%, while the alternative hypothesis (H1) was increased up to 40%. With Simon’s two-stage Minimax design, 21 patients were estimated. At least 3 cases of the 15 first patients (first stage) should have ≥6-m PFS. Then, an additional six evaluable patients would be accrued (second stage) and to reject the null hypothesis at least six patients should have a 6-m PFS or longer.Those patients who provided written consent, whose tumors were centrally confirmed for the histotype and molecular expression, formed the intention-to-treat population. The per-protocol population was defined as the subset of the intention-to-treat population with measurable disease at study entry (as per RECIST criteria). Patients in this population also received at least one month (one cycle) of treatment and had at least one radiological assessment. Otherwise, the patient was not considered assessable (the exception was early progression or death, for which patients were included). Patients who received at least one dose of palbociclib were considered evaluable for toxicity.Variables following binomial distributions (i.e. response rate), were expressed as frequencies and percentages. Comparisons between qualitative variables were done using the Fisher Exact Test or Chi-square. Comparisons between quantitative and qualitative variables were performed through non-parametric tests (