DNA Based Therapy with Diphtheria Toxin-A BC-819: A Phase 2b Marker Lesion Trial in Patients with Intermediate Risk Nonmuscle Invasive Bladder Cancer

Purpose: H19 is a paternally imprinted oncofetal gene expressed in various embryonic tissues and in 85% of bladder tumors but suppressed in the adult healthy bladder. BC-819 is a DNA plasmid that carries the gene for diphtheria toxin-A under regulation of the H19 promoter sequence. We assessed the efficacy and toxicity of intravesical BC-819 instillations to prevent tumor recurrence and ablate a marker lesion in a phase 2b trial.Materials and Methods: A total of 47 patients with recurrent, multiple nonmuscle invasive bladder tumors in whom prior intravesical therapy had failed underwent transurethral resection of all except 1 marker tumor. Patients expressing H19 received a 6-week induction course of intravesical BC-819. Patients who achieved a complete response (absent new tumors at 3 months) were given 3 maintenance courses of 3-weekly instillations every 3 months.Results: All patients were evaluable for adverse effects and 39 were evaluable for efficacy. Complete tumor ablation was achieved in 33% of p...