Phase I rapid dose-escalation study of AGS-1C4D4, a human anti-PSCA (prostate stem cell antigen) monoclonal antibody, in patients with castration-resistant prostate cancer: A PCCTC trial Journal Article


Authors: Antonarakis, E. S.; Carducci, M. A.; Eisenberger, M. A.; Denmeade, S. R.; Slovin, S. F.; Jelaca-Maxwell, K.; Vincent, M. E.; Scher, H. I.; Morris, M. J.
Article Title: Phase I rapid dose-escalation study of AGS-1C4D4, a human anti-PSCA (prostate stem cell antigen) monoclonal antibody, in patients with castration-resistant prostate cancer: A PCCTC trial
Abstract: Purpose: AGS-1C4D4 is a human monoclonal antibody against prostate stem cell antigen (PSCA), a cell-surface protein expressed by most prostate cancers. AGS-1C4D4 is produced in Chinese hamster ovary (CHO) cells and has an identical sequence to AGS-PSCA, an anti-PSCA antibody produced in mouse hybridoma cells that has completed Phase I testing. Preclinical studies demonstrated comparability of AGS-1C4D4 to AGS-PSCA with respect to pharmacokinetics (PK) and tumor inhibition. However, because of differences in antibody-dependent cellular cytotoxicity between AGS-PSCA and AGS-1C4D4, a limited Phase I trial using AGS-1C4D4 was performed evaluating safety and PK. Patients and methods: Thirteen patients with metastatic castration-resistant prostate cancer were enrolled. AGS-1C4D4 was administered intravenously every 3 weeks for four planned doses at 6, 12, 24, or 48 mg/kg. Primary endpoints were safety and PK. Secondary endpoints were immunogenicity and clinical activity. Disease assessments were conducted every 12 weeks and included radiographic and PSA evaluations. Patients with stable disease could receive extended treatment beyond four infusions. Results: Adverse events were primarily grade 1-2, without any grade 3-4 drug-related toxicities or infusion reactions. Anti-AGS-1C4D4 antibodies were not detected. Similar to AGS-PSCA, serum AGS-1C4D4 concentrations declined biphasically and elimination was characterized by slow clearance (CL) and a long terminal half-life (t 1/2). Median CL for the four dose levels ranged from 0.10 to 0.14 ml/h kg, and t 1/2 ranged from 2.2 to 2.9 weeks. No PSA reductions ≥50% were observed. Six patients (46%) had radiographically stable disease, lasting a median of 24 weeks. Conclusion: AGS-1C4D4 was well-tolerated and demonstrated linear PK. Despite preclinical differences in antibody-dependent cellular cytotoxicity, AGS-1C4D4 and AGS-PSCA have similar safety and PK profiles. The recommended Phase II dose is 48 mg/kg. © 2011 Springer-Verlag.
Keywords: monoclonal antibody; phase i; castration-resistant prostate cancer; ags-1c4d4; psca
Journal Title: Cancer Chemotherapy and Pharmacology
Volume: 69
Issue: 3
ISSN: 0344-5704
Publisher: Springer  
Date Published: 2012-03-01
Start Page: 763
End Page: 771
Language: English
DOI: 10.1007/s00280-011-1759-9
PROVIDER: scopus
PUBMED: 22020316
PMCID: PMC3586214
DOI/URL:
Notes: --- - "Cited By (since 1996): 2" - "Export Date: 1 May 2012" - "CODEN: CCPHD" - "Source: Scopus"
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  1. Susan Slovin
    254 Slovin
  2. Michael Morris
    579 Morris
  3. Howard Scher
    1130 Scher