ABBV-319: a CD19-targeting glucocorticoid receptor modulator antibody-drug conjugate therapy for B-cell malignancies.

ABSTRACT: Glucocorticoids are key components of the standard-of-care treatment regimens for B-cell malignancy. However, systemic glucocorticoid treatment is associated with several adverse events. ABBV-319 is a CD19-targeting antibody-drug conjugate engineered to reduce glucocorticoid-associated toxicities while possessing 3 distinct mechanisms of action (MOA) to increase therapeutic efficacy: (1) antibody-mediated delivery of a glucocorticoid receptor modulator (GRM) payload to activate apoptosis, (2) inhibition of CD19 signaling, and (3) enhanced fragment crystallizable (Fc)-mediated effector function via afucosylation of the antibody backbone. ABBV-319 elicited potent GRM-driven antitumor activity against multiple malignant B-cell lines in vitro, as well as in cell line-derived xenografts and patient-derived xenografts (PDXs) in vivo. Remarkably, a single dose of ABBV-319 induced sustained tumor regression and enhanced antitumor activity compared with repeated dosing of systemic prednisolone at the maximum tolerated dose in mice. The unconjugated CD19 monoclonal antibody (mAb) also displayed antiproliferative activity in a subset of B-cell lymphoma cell lines through the inhibition of phosphoinositide 3-kinase signaling. Moreover, afucosylation of CD19 mAb enhanced Fc-mediated antibody-dependent cellular cytotoxicity. Notably, ABBV-319 displayed superior efficacy compared with afucosylated CD19 mAb in human CD34+ peripheral blood mononuclear cell-engrafted NSG-Tg(Hu-IL15) transgenic mice, demonstrating enhanced antitumor activity when multiple MOAs are enabled. ABBV-319 also showed durable antitumor activity across multiple B-cell lymphoma PDX models, including nongerminal center B-cell diffuse large B-cell lymphoma and relapsed lymphoma after R-CHOP treatment. Collectively, these data support the ongoing evaluation of ABBV-319 in a phase 1 clinical trial.

Simvastatin protects against amyloid beta and HIV-1 Tat-induced promoter activities of inflammatory genes in brain endothelial cells.

Increased deposition of amyloid beta (Abeta) is characteristic for normal aging and human immunodeficiency virus-1 (HIV-1)-associated alterations of the central nervous system. In addition, both Abeta and HIV-1 are known to induce cellular oxidative stress and disruption of the blood-brain barrier (BBB). Therefore, we hypothesize that Abeta and HIV-1 protein Tat can potentiate their proinflammatory effects at the brain endothelium level. To address this hypothesis, we studied promoter activity of three proinflammatory genes in an in vitro BBB model of human brain microvascular endothelial cells (HBMEC) cocultured with a human astrocyte cell line producing Tat (SVGA-Tat cells) and exposed to Abeta. Treatment of HBMEC with Abeta(1-40) in the presence of SVGA-Tat cells resulted in a significant up-regulation of E-selectin, CC chemokine ligand-2, and interleukin-6 promoter activities and protein levels compared with the individual effects of Abeta or Tat. In addition, Abeta markedly amplified E-selectin promoter activity in HBMEC cocultured with HIV-1-infected Jurkat T cells. Simvastatin, the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, effectively blocked proinflammatory reactions induced by Abeta in cocultures with SVGA-Tat cells or with HIV-1-infected Jurkat cells. The present study indicates that a combined exposure to Abeta and Tat or HIV-1 can synergistically potentiate the expression of inflammatory genes in brain endothelial cells. In addition, simvastatin may provide a beneficial influence by reducing these effects at the BBB level.