Real-world evidence analysis of palbociclib prescribing patterns for patients with advanced/metastatic breast cancer treated in community oncology practice in the USA one year post approval

Table 3 CBC laboratory evaluations during palbociclib + letrozole treatment and occurrence, timing and grade of neutropenia

	Throughout palbociclib treatment		First 6 cycles^c		First 4 cycles^d		First 2 cycles^e
Total patients (n (%))	612	(100.0)	497	(81.2)	551	(90.0)	575	(94.0)
Patients with ≥ 1 CBC/WBC during time period (n (%))	351	(57.4)	299	(60.2)	316	(57.4)	316	(55.0)
Number of CBC/WBC tests (mean (SD))^a	6.0	(5.7)	5.3	(4.5)	4.7	(3.6)	3.3	(2.2)
Laboratory value consistent with neutropenia^b while on PAL (n (%))	262	(74.6)	262	(91.0)	262	(85.3)	243	(76.9)
Days to neutropenia diagnosis (mean (SD))	28.4	(19.6)	28.4	(19.6)	28.4	(19.6)	24.2	(12.6)

CBC complete blood count, WBC white blood cell count, ANC absolute neutrophil count, PAL palbociclib
^aOnly patients with at least one laboratory test result were counted in calculating the frequency of CBC/WBC tests, neutrophil count during palbociclib treatment, and grade of neutropenia
^bNeutropenia = neutrophil percentage divided by 100, multiplied by WBC quantity (neutrophil value in K/μl), and multiplied by 1000 to convert to mm³
^cInterval from initiation of palbociclib + letrozole through 168 days post initiation among those considered on palbociclib + letrozole at day 168 post initiation and those who received test/experienced event prior to the end of the interval
^dInterval from initiation of palbociclib + letrozole through 112 days post initiation among those considered on palbociclib + letrozole at day 112 post initiation, and those who received test/experienced event prior to the end of the interval
^eInterval from initiation of palbociclib + letrozole through 56 days post initiation among those considered on palbociclib + letrozole at day 56 post initiation, and those who received test/experienced event prior to the end of the interval

ISSN: 1465-542X