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Purpose: To investigate the relationship of pembrolizumab pharmacokinetics (PK) and overall survival (OS) in patients with advanced melanoma and non-small cell lung cancer (NSCLC)., Patients and Methods: PK dependencies in OS were evaluated across three pembrolizumab studies of either 200 mg or 2 to 10 mg/kg every 3 weeks (Q3W). Kaplan-Meier plots of OS, stratified by dose, exposure, and baseline clearance (CL 0 ), were assessed per indication and study. A Cox proportional hazards model was implemented to explore imbalances of typical prognostic factors in high/low NSCLC CL 0 subgroups., Results: A total of 1,453 subjects were included: 340 with pembrolizumab-treated melanoma, 804 with pembrolizumab-treated NSCLC, and 309 with docetaxel-treated NSCLC. OS was dose independent from 2 to 10 mg/kg for pembrolizumab-treated melanoma [HR = 0.98; 95% confidence interval (CI), 0.94-1.02] and NSCLC (HR = 0.98; 95% CI, 0.95-1.01); however, a strong CL 0 -OS association was identified for both cancer types (unadjusted melanoma HR = 2.56; 95% CI, 1.72-3.80 and NSCLC HR = 2.64; 95% CI, 1.94-3.57). Decreased OS in subjects with higher pembrolizumab CL 0 paralleled disease severity markers associated with end-stage cancer anorexia-cachexia syndrome. Correction for baseline prognostic factors did not fully attenuate the CL 0 -OS association (multivariate-adjusted CL 0 HR = 1.64; 95% CI, 1.06-2.52 for melanoma and HR = 1.88; 95% CI, 1.22-2.89 for NSCLC)., Conclusions: These data support the lack of dose or exposure dependency in pembrolizumab OS for melanoma and NSCLC between 2 and 10 mg/kg. An association of pembrolizumab CL 0 with OS potentially reflects catabolic activity as a marker of disease severity versus a direct PK-related impact of pembrolizumab on efficacy. Similar data from other trials suggest such patterns of exposure-response confounding may be a broader phenomenon generalizable to antineoplastic mAbs. See related commentary by Coss et al., p. 5787 ., (©2018 American Association for Cancer Research.)

Purpose: Voreloxin, a novel replication-dependent DNA-damaging agent, intercalates DNA and inhibits topoisomerase II. Voreloxin induces site-selective DNA double-strand breaks and apoptosis. We report the phase 1 experience of voreloxin in patients with relapsed/refractory solid tumors, including dose-limiting toxicity (DLT), maximum-tolerated dose (MTD), pharmacokinetics, and clinical activity., Experimental Design: Two dose-escalation studies evaluated voreloxin administered i.v. every 3 weeks (SPO-0001) or weekly for 3 weeks every 28 days (SPO-0002). In SPO-0001, patients were classified as heavily pretreated (HP) or minimally pretreated (MP) based on therapeutic history., Results: In the SPO-0001 study, 41 patients (24 HP/17 MP) were treated in eight dose cohorts (3-75 mg/m(2)). At 60 mg/m(2), four HP patients experienced DLTs: grade 4 neutropenia (n = 3, one with fever) and grade 3 febrile neutropenia/pneumonia (n = 1). At 75 mg/m(2), two MP patients experienced DLTs: grade 4 neutropenia/thrombocytopenia (n = 1) or grade 2 oral thrush for >29 days (n = 1). Therefore, the MTD was 48 mg/m(2) (HP patients) and 60 mg/m(2) (MP patients). In the SPO-0002 study, 21 patients were treated in six dose cohorts (3-24 mg/m(2)). At 18 mg/m(2), two patients experienced DLTs: grade 3 neutropenia, one with pleural effusion (>14 days each). The MTD was 15 mg/m(2). Voreloxin exhibited low clearance (2 L/h/m(2)), a long terminal half-life (22 hours), and dose-proportional exposure. Overall, 31 of 62 patients had stable disease and 1 patient (ovarian cancer) had a partial response per Rustin criteria., Conclusions: Voreloxin showed an acceptable safety profile with clinical activity in patients with relapsed/refractory solid tumors. The MTD was schedule-dependent. Voreloxin is currently in clinical studies of ovarian cancer and acute myeloid leukemia., (Copyright 2010 AACR.)