RESUMO
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.
Assuntos
Antineoplásicos Imunológicos/farmacologia , Biomarcadores Tumorais/antagonistas & inibidores , Glutamato Carboxipeptidase II/antagonistas & inibidores , Imunoconjugados/farmacologia , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/imunologia , Animais , Antígenos de Superfície/genética , Antígenos de Superfície/metabolismo , Linhagem Celular Tumoral , Reações Cruzadas/imunologia , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Expressão Gênica , Glutamato Carboxipeptidase II/genética , Glutamato Carboxipeptidase II/metabolismo , Humanos , Imuno-Histoquímica , Macaca fascicularis , Masculino , Camundongos , Neoplasias da Próstata/patologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
In recent decades, mAbs have been used increasingly as targeted therapeutics for various diseases. However, the selective nature of antibodies can often lead to mAbs that do not recognize the target antigen in a preclinical model species used in studies of in vivo efficacy and safety. This feature review article focuses on the use of alternative animal models and surrogate antibodies for studies of efficacy for cases in which the primary therapeutic antibody does not recognize the antigen in a relevant species. In addition, the use of rodent and non-human primate models for preclinical safety studies with mAbs is discussed.