Abstract
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Background: Cabazitaxel (C) and abiraterone (A) improve survival in mCRPC after progression on docetaxel (D). We examined whether mCRPC patients progressing on D received C and/or A, in which sequence, and how they compared with patients not receiving C or A. Methods: This retrospective study used medical records from the ACORN Data Warehouse. Eligible patients were: diagnosed with mCRPC, progressed after 1st-line D, treated 2nd-line with C (DC) or A (DA). Some went to 3rd-line C or A (DCA, DAC). A random sample of comparable patients without A or C (DO) was included. Demographic and clinical characteristics were extracted. Cox regression analyses assessed PFS and OS by 2nd-line group after D. Results: Screened out patients were: 60 with no progression on D; 41 absent records; 18 with another cancer. Table below shows patients by treatment sequence group. Age, PS, and PSA did not differ significantly. More patients appear to have received A after C (56.7%) than C after A (25.7%). In the 3-drug sequence groups, more patients received DCA in the 6-month period from April-October 2011 (n = 17/19) than in the 6-month period from June-December 2012 (n = 2/10), suggesting a drop-off in use of C immediately after D. Cox PFS treatment effect was not significant. Cox OS treatment effect was significant (DA vs DC, HR = 1.693 [95% CI: 1.066, 2.691], p = 0.0258). Conclusions: Patterns suggest comparable outcomes in PFS. Controlling for patient characteristics, OS may be longer in DC vs DA. Patients appear undertreated in third line with fewer receiving C after A than the opposite sequence. We hypothesize that DAC may not be as feasible as DCA. Reasons for underutilization of C are being examined.
Patient demographic and clinical characteristics.* | Characteristic | DC
n = 60 | DA
n = 71 | DCA
n = 34 | DAC
n = 18 | DO
n = 129 | Total
n= 260 | | Age (median years) | 68.97 | 70.83 | 68.88 | 67.00 | 68.95 | 69.47 | | PS, n (%) impaired vs. not indicated impaired | 8 (13.33) | 12 (16.90) | 5 (14.71) | 3 (16.67) | 16 (12.4) | 36 (13.85) | | PSA ng/mL (n) | 49 | 50 | 27 | 14 | 95 | 194 | | Median | 221.00 | 82.00 | 264.80 | 67.50 | 111.00 | 111.95 |
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© 2013 by American Society of Clinical Oncology
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