Yu Y, Elmeliegy M, Litton JK, Tudor IC, Czibere A, Zheng J, Wang DD. Talazoparib Exposure-Efficacy Analysis in Patients With Advanced Breast Cancer and Germline BRCA1/2 Mutations in the EMBRACA Trial.
J Clin Pharmacol 2020;
60:1324-1333. [PMID:
32468579 DOI:
10.1002/jcph.1623]
[Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 03/25/2020] [Indexed: 11/08/2022]
Abstract
In the phase 3 EMBRACA trial, treatment with the poly(ADP-ribose) polymerase inhibitor, talazoparib, led to significantly improved progression-free survival (PFS) compared with chemotherapy (hazard ratio, 0.54; 95% confidence interval, 0.41-0.71; P < .0001). We conducted an exposure-efficacy analysis using EMBRACA data from 285 patients who were treated with talazoparib and had available pharmacokinetic parameters to evaluate the effect of talazoparib exposure (time-varying average talazoparib concentration [Cavg,t ]) and other baseline variables on PFS. Graphical examination of the relationship between Cavg,t and PFS and a Cox proportional model were used. Exposure-response analyses showed that higher talazoparib exposure, absence of visceral disease, lower baseline lactate dehydrogenase levels, and disease-free interval >12 months were independent covariates associated with longer PFS. The association of talazoparib exposure with PFS (higher exposure, longer PFS) suggests the recommended starting dose of 1 mg once daily (the maximum tolerated dose) is appropriate.
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