H19 promoter-driven diphtheria toxin A (BC-819)

H19 promoter-driven diphtheria toxin A (H19-DTA) is a targeted gene therapy construct designed for the selective destruction of cancer cells. It leverages the oncofetal H19 promoter, which is transcriptionally active in many human malignancies—such as bladder, ovarian, and pancreatic cancers—while remaining largely inactive in normal adult tissues (Ariel et al., 2000, PubMed: 10863518). The construct delivers a DNA plasmid encoding the A-chain of diphtheria toxin (DTA). Once the plasmid enters a cell where the H19 promoter is active, DTA is expressed and inhibits protein synthesis by ADP-ribosylating elongation factor 2, ultimately triggering apoptosis. This approach aims to provide a targeted cytotoxic effect while minimizing systemic toxicity by restricting toxin production to the tumor microenvironment. Clinical development, particularly for the drug candidate BC-819, has primarily focused on intravesical administration for non-muscle invasive bladder cancer, where it has demonstrated the ability to reduce tumor recurrence in patients who failed standard therapies (Sidi et al., 2008, PubMed: 18660453).

Other names

DTA-H19CyntoluxH19-DTA plasmidInhibitor of protein synthesis driven by H19 promoterH19-DTA

The therapeutic construct utilizes the H19 promoter, which is highly active in various tumor types but silenced in healthy adult tissues, to drive the expression of the Diphtheria Toxin A (DTA) gene (Amit and Hochberg, 2010, PubMed: 20815758). Upon entry into H19-expressing cancer cells, the DTA protein is produced and catalyzes the ADP-ribosylation of eukaryotic Elongation Factor 2 (eEF-2). This modification inactivates eEF-2, leading to the total cessation of protein synthesis and subsequent cell death via apoptosis (Mizrahi et al., 2009, PubMed: 19609358).