ARQ 761 is an intravenously administered analogue of β-Lapachone, a naturally existing substance. ARQ 761 is a pro-drug of ARQ 501 and has demonstrated in vitro activity against a wide range of solid tumors. In Phase 1a testing with single agent ARQ 761, anti-cancer activity as measured by tumor responses occurred exclusively in a portion of patients with high levels of NQO1.
ARQ 761 is an NQO1 inhibitor, with the potential to enhance the effect of chemotherapy and other cancer therapies, which is over-expressed in many cancers.
Phase 1a testing with ARQ 761 identified anti-cancer activity, as measured by tumor responses, that occurred exclusively in a portion of the patient population with high levels of NQO1.
NQO1 is over-expressed in many cancers. For instance, ~90% of pancreatic and NSCLC cancers express NQO1 10-100 fold, while ~60% of breast, prostate and colon cancers express NQO1 5-20 fold. NQO1, in combination with chemotherapy or PARP inhibitors, has shown efficacy in multiple cancer lines.