Censavudine (OBP-601; BMS-986001), a nucleoside analog, is a nucleoside reverse transcriptase inhibitor. Censavudine is a potent HIV inhibitor with EC50 ranges from 30 nM to 81 nM and 450 nM to 890 nM for HIV-2 and HIV-1, respectively[1][2].

BMS-986001 shows greater activity against HIV-2ROD9 than against HIV-1NL4-3; the mean EC50s for BMS-986001 are 74 nM for HIV-2ROD9 and 890 nM for HIV-1NL4-3 in the single-cycle assay. HIV-2ROD9 also showes greater sensitivity to BMS-986001 in 4-day infections of an immortalized T cell line (CEMss), with the mean EC50 for HIV-2ROD9 (EC50 of 0.14 nM) being 30-fold lower than that for HIV-1NL4-3 (EC50 of 4.2 nM)[1].BMS-986001 also exhibits full activity against HIV-2 variants whose genomes encoded the single amino acid changes K65R and Q151M in reverse transcriptase[1].

The pharmacokinetic parameters of Censavudine (BMS-986001; 100-750 mg/kg) generated from the dried blood spot (DBS) assay and the plasma assay is compared. The ratios of the AUC(0-24 h) and C max for BMS-986001 in DBS compared to those in plasma are consistent at 0.83-0.91 and 0.81-0.97, respectively, across all dose groups in rats. The T max in rat DBS and plasma are also consistent at about 1 h[2].

[1]. Robert A Smith, et al. The Nucleoside Analog BMS-986001 Shows Greater In Vitro Activity Against HIV-2 Than Against HIV-1. Antimicrob Agents Chemother. 2015 Dec;59(12):7437-46.
[2]. Long Yuan, et al. Dried Blood Spot Analysis Without Dilution: Application to the LC-MS/MS Determination of BMS-986001 in Rat Dried Blood Spot. J Chromatogr B Analyt Technol Biomed Life Sci. 2015 Oct 1;1002:201-9.