In contrast to BL, serum creatinine levels decreased in subjects receiving BCV 100 mg BIW and increased in placebo recipients at treatment week 10 (5

In contrast to BL, serum creatinine levels decreased in subjects receiving BCV 100 mg BIW and increased in placebo recipients at treatment week 10 (5. 6 versus 14. 0 M; P= 0. 03, Satterthwaitettest); this improvement continuing through posttreatment week 1 (4. 7 versus 12. 8 M; P= 0. 03). == The mobile uptake of BCV as well as its major metabolites was assessed in vitro. Renal function at baseline and during and after treatment in subjects in BCV medical studies was examined. == Results: == In OAT1-expressing cells, uptake of BCV and its 2 major metabolites (CMX103 and CMX064) was the same as in mock-transfected control cells and was not inhibited by the OAT inhibitor probenecid. In individual pharmacokinetic studies, BCV operations at therapeutic doses led to detection of CDV like a circulating metabolite; peak CDV plasma concentrations after dental BCV operations in humans were <1% of these observed after IV CDV administration at therapeutic dosages. Analysis of renal function and unfavorable events coming from 3 BCV clinical studies in immunocompromised adult and pediatric subject matter indicated little to no evidence of associated nephrotoxicity. Over 80% of subjects who also switched coming from CDV or foscarnet to BCV experienced an improvement in renal function as measured by Fosfosal maximum on-treatment estimated glomerular filtration price. == Findings: == Deficiency of BCV uptake through OAT1, together with reduced CDV concentrations after dental BCV in contrast to IV CDV administration, likely explains the superior renal safety profile observed in immunocompromised subjects receiving Fosfosal BCV in contrast to CDV. == INTRODUCTION == Brincidofovir (BCV) is an orally bioavailable lipid conjugate of cidofovir (CDV) (Fig. 1) that preferentially delivers the antiviral moiety CDV diphosphate to the intracellular space, avoiding the significant nephrotoxicity that limits the effectiveness of CDV. CDV is given by intravenous (IV) infusion and provides substantial concentrations of circulating drug in the plasma. CDV is then Fosfosal actively transported into renal proximal tubule epithelial cells by the individual organic anion transporter 1 (OAT1). 13Dose-limiting nephrotoxicity after IV operations of CDV has been exhibited in both animals and humans. 13Severe nephrotoxicity resulting in renal failure and death has occurred after a solitary IV operations of CDV. 4Recommendations to ameliorate CDV-associated nephrotoxicity consist of prehydration with normal saline and coadministration of probenecid, an inhibitor of OATs. 48Despite these protective steps, nephrotoxicity continues to be a significant risk and limits the medical utility of CDV. == FIGURE 1 . == Chemical structures of BCV and metabolites. The proprietary BCV molecule, with its lipid moiety, is designed to mimic the organic lipid lysophosphatidylcholine and to make use of endogenous lipid uptake pathways to achieve intracellular concentrations of BCV that provide antiviral activity against a broad range of double-stranded DNA (dsDNA) viruses. In cell-based assays, BCV exhibited activity against all five families of dsDNA viruses that cause individual disease, including orthopoxviruses, polyomaviruses, human herpesviruses, human papillomaviruses, and adenoviruses (AdVs). 9BCV has also exhibited antiviral activity in dog models of dsDNA virus illness, including herpesviruses, 10, 11AdVs, 12and poxviruses. 1316BCV (Chimerix, Durham, NC) is in late-stage clinical advancement for the treatment of serious AdV infection [the Guide study, CMX001-304 (NCT02087306)] and for the prevention of cytomegalovirus (CMV) infection in hematopoietic cell transplant (HCT) recipients [the recently completed CONTROL study CMX001-301 (NCT01769170)], and is in pivotal efficacy studies for the treatment of smallpox in well-described dog models under the Food and Drug Administration’s Animal Guideline. Herein, we present data confirming deficiency of in vitro uptake of BCV as well as its major metabolites by OAT1 and summarize the pharmacokinetic (PK) and renal protection profiles seen after BCV administration in clinical studies. == COMPONENTS AND METHODS == == Human OAT-Mediated Cellular Uptake of BCV and Metabolites == Epithelial MadinDarby doggy kidney type 2 (MDCK-II) cells were grown on semipermeable filters and transiently transfected with OAT1, OAT3, or vector only (Optivia Biotechnology, Menlo Fosfosal Park, CA). BCV as well as its major metabolites CMX103 (3-hydroxypropyl ester of CDV) and CMX064 [4-(3-propoxy) butanoic acid ester of CDV]17or CDV (Gilead Sciences, Foster City, CA) IgG2a/IgG2b antibody (FITC/PE) were added to the basolateral side of the cell monolayer (n= 34 replicates/condition), with or without probenecid (100 M). A higher incubation concentration of each of the metabolites (25 versus 5 M) was used to obtain detectable concentrations of these more polar substances in mock-transfected cells. After a 5-minute incubation, drugs were removed from cells, and the cells were rinsed, extracted, and analyzed using high-performance liquid chromatographytandem mass spectrometry. Net OAT-mediated uptake was established from total uptake in OAT-expressing cells minus uptake in vector-treated control cells. The Fosfosal minimum established popularity.