Real-World Effectiveness of Palbociclib in Combination With an Aromatase Inhibitor

OS was defined as the time from the index date (start of palbociclib + AI or AI alone) to death. Participants who did not die, were censored at the end of study date (30-Sep-2020). Kaplan-Meier method adjusted by stabilized inverse probability of treatment weighting (sIPTW) was used.

Real-world PFS was defined as the number of months from start of palbociclib + AI or AI alone to death from any cause or disease progression (based on clinical assessment or by radiographic scan/tissue biopsy), whichever occurred first. Disease progression was defined as at least a 20 percentage (%) increase in the sum of diameters of target lesions, taking as reference the smallest sum on study (this includes the baseline sum if that was the smallest on study). Participants who did not die and did not have disease progression were censored at the date of initiation of next line of therapy for participants with 2 or more lines of therapy or at the date of their last visit during the study period (February 2015-September 2020) for participants with only 1 line of therapy. Kaplan-Meier method adjusted by stabilized IPTW was used.

Real-world best responses were assessed based on treating clinician's assessment of radiological evidence for change in burden of disease over course of treatment after 1 month of index treatment initiation. Responses were classified as complete response (CR), partial response (PR), stable disease (SD), progressive disease (PD), indeterminate response (IR). CR=Complete resolution of all visible disease. PR=partial reduction in size of visible disease in some or all areas without any areas of increase in visible disease. SD=no change in overall size of visible disease. PD: an increase in visible disease; also included cases where some lesions increased in size and some lesions decreased in size; included cases where clinician indicated progressive disease; IR=study data not available for evaluation of efficacy for any reason, including participants lost to follow-up or assessment not undertaken or death. Analysis was performed using sIPTW method to balance participant characteristics.

Real-world tumor response rate (rwTR) was defined as the percentage of participants with a real world complete response (rwCR) or real-world partial response (rwPR). CR: complete resolution of all visible disease. PR: partial reduction in size of visible disease in some or all areas without any areas of increase in visible disease. Analysis was performed using sIPTW method to balance participant characteristics.

Number of participants according to the initial dose of palbociclib (75 milligrams [mg]/day, 100mg/day, 125 mg/day or missing dose) are reported in this outcome measure.

Time to dose adjustment for participants who received palbociclib 125 mg/day, 100 mg/day, or 75 mg/day as initial dose was presented in this outcome measure.

Duration of treatment was defined as days from index prescription order date to end of treatment, start of subsequent line of therapy, or death from any cause, whichever occurred first. Kaplan-Meier method adjusted by stabilized IPTW was used.

Time to next line of treatment represents the interval from commencement of one treatment to initiation of the next line of therapy. Analysis was performed using sIPTW method to balance participant characteristics among reporting groups.

Time to subsequent chemotherapy represents the time interval to administration of a different chemotherapeutic agent after the first course of therapy was administered. Analysis was performed using sIPTW method to balance participant characteristics among reporting groups.

rwPFS2 was defined as the time from the index date to the date of the first documentation of a rwPD or death due to any cause after starting second line of therapy, whichever occurs first. Disease progression was defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study (this includes the baseline sum if that was the smallest on study). In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. Analysis was performed using sIPTW method to balance participant characteristics among reporting groups.