Iniparib, previously named BSI-201, is an intravenously administered PARP1 inhibitor, which either alone or in combination with chemotherapy, has important antitumor activity in studies in vitro and in vivo. It is active against a broad range of cancer cells in culture, including drug resistant cell lines. Iniparib has been reported to be a prodrug whose C-nitroso metabolite, 4-iodo-3-nitrosobenzamide, selectively kills tumor cells by oxidizing the zinc finger of PARP-1 resulting in ejection of zinc and inhibition of PARP activity.

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