MOR209/ES414, a Novel Bispecific Antibody Targeting PSMA for the Treatment of Metastatic Castration-Resistant Prostate Cancer.

Treatment of metastatic, castration-resistant prostate cancer (mCRPC) remains a highly unmet medical need and current therapies ultimately result in disease progression. Immunotherapy is a rapidly growing approach for treatment of cancer but has shown limited success to date in the treatment of mCRPC. We have developed a novel humanized bispecific antibody, MOR209/ES414, built on the ADAPTIR (modular protein technology) platform, to redirect T-cell cytotoxicity toward prostate cancer cells by specifically targeting T cells through CD3ε to prostate cancer cells expressing PSMA (prostate-specific membrane antigen). In vitro cross-linking of T cells with PSMA-expressing tumor cells by MOR209/ES414 triggered potent target-dependent tumor lysis and induction of target-dependent T-cell activation and proliferation. This activity occurred at low picomolar concentrations of MOR209/ES414 and was effective at low T-effector to tumor target cell ratios. In addition, cytotoxic activity was equivalent over a wide range of PSMA expression on target cells, suggesting that as few as 3,700 PSMA receptors per cell are sufficient for tumor lysis. In addition to high sensitivity and in vitro activity, MOR209/ES414 induced limited production of cytokines compared with other bispecific antibody formats. Pharmacokinetic analysis of MOR209/ES414 demonstrated a serum elimination half-life in NOD/SCID γ (NSG) mice of 4 days. Administration of MOR209/ES414 in murine xenograft models of human prostate cancer significantly inhibited tumor growth, prolonged survival, and decreased serum prostate-specific antigen levels only in the presence of adoptively transferred human T cells. On the basis of these preclinical findings, MOR209/ES414 warrants further investigation as a potential therapeutic for the treatment of CRPC. Mol Cancer Ther; 15(9); 2155-65. ©2016 AACR.

VSGP/F-spondin: a new ovarian cancer marker.

The discovery of genes that are overexpressed in ovarian cancers provides valuable insight into ovarian cancer biology and will lead to the development of more effective treatment strategies for combating this disease. To identify genes exhibiting ovarian- and ovarian cancer-specific expression, we generated four subtracted cDNA libraries from primary and metastatic ovarian adenocarcinoma tissues. 3,400 cDNA clones from these libraries were analyzed by microarray for tissue distribution and tumor specificity using 32 pairs of fluorophore-labeled cDNA samples from a variety of normal tissues and ovarian tumor tissues. cDNA clones showing elevated expression in ovarian tumors were identified by DNA sequencing with comparison to public databases, and the most promising candidates were further analyzed by quantitative real-time polymerase chain reaction and Northern blot. This systematic approach led to the identification of a number of genes including vascular smooth muscle growth-promoting factor (VSGP/F-spondin), a secreted protein previously identified and cloned from bovine and human ovary. VSGP/F-spondin protein was observed in ovarian carcinomas but not in normal ovarian epithelium by immunohistochemistry with a VSGP/F-spondin antibody. The expression profile of VSGP/F-spondin identifies this molecule as a potential diagnostic marker or target for developing therapeutic strategies to treat ovarian carcinoma.