Antitumor Activity of MEDI3726 (ADCT-401), a Pyrrolobenzodiazepine Antibody-Drug Conjugate Targeting PSMA, in Preclinical Models of Prostate Cancer

Mol Cancer Ther. 2018 Oct;17(10):2176-2186. doi: 10.1158/1535-7163.MCT-17-0982. Epub 2018 Jul 31.


Prostate-specific membrane antigen (PSMA) is a membrane-bound glutamate carboxypeptidase that is highly expressed in nearly all prostate cancers with the highest expression in metastatic castration-resistant prostate cancer (mCRPC). The prevalence of increased surface expression and constitutive internalization of PSMA make it an attractive target for an antibody-drug conjugate (ADC) approach to treating patients with mCRPC. MEDI3726 (previously known as ADCT-401) is an ADC consisting of an engineered version of the anti-PSMA antibody J591 site specifically conjugated to the pyrrolobenzodiazepine (PBD) dimer tesirine. MEDI3726 specifically binds the extracellular domain of PSMA and, once internalized, releases the PBD dimer to crosslink DNA and trigger cell death. In vitro, MEDI3726 demonstrated potent and specific cytotoxicity in a panel of PSMA-positive prostate cancer cell lines, consistent with internalization and DNA interstrand crosslinking. In vivo, MEDI3726 showed robust antitumor activity against the LNCaP and the castration-resistant CWR22Rv1 prostate cancer cell line xenografts. MEDI3726 also demonstrated durable antitumor activity in the PSMA-positive human prostate cancer patient-derived xenograft (PDX) LuCaP models. This activity correlated with increased phosphorylated Histone H2AX in tumor xenografts treated with MEDI3726. MEDI3726 is being evaluated in a phase I clinical trial as a treatment for patients with metastatic castrate-resistant prostate cancer (NCT02991911). Mol Cancer Ther; 17(10); 2176-86. ©2018 AACR.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Surface / genetics
  • Antigens, Surface / metabolism
  • Antineoplastic Agents, Immunological / pharmacology*
  • Biomarkers, Tumor / antagonists & inhibitors*
  • Cell Line, Tumor
  • Cross Reactions / immunology
  • Disease Models, Animal
  • Drug Evaluation, Preclinical
  • Gene Expression
  • Glutamate Carboxypeptidase II / antagonists & inhibitors*
  • Glutamate Carboxypeptidase II / genetics
  • Glutamate Carboxypeptidase II / metabolism
  • Humans
  • Immunoconjugates / pharmacology*
  • Immunohistochemistry
  • Macaca fascicularis
  • Male
  • Mice
  • Prostatic Neoplasms / drug therapy*
  • Prostatic Neoplasms / immunology*
  • Prostatic Neoplasms / pathology
  • Xenograft Model Antitumor Assays


  • Antigens, Surface
  • Antineoplastic Agents, Immunological
  • Biomarkers, Tumor
  • Immunoconjugates
  • FOLH1 protein, human
  • Glutamate Carboxypeptidase II

Associated data