Molecular bases for targeting bile acid-cisplatin derivatives Bamet-R2 [cis-diammine-chloro-cholylglycinate-platinum(II)]and Bamet-UD2 [cis-diammine-bisursodeoxycholate-platinum(II)] toward liver cells were investigated. Carriers for bile acids [human Na ϩ -taurocholate cotransporting polypeptide (NTCP)], organic anions [organic anion transporting polypeptide (OATP)], and organic cations [organic cation transporter (OCT)] were expressed in Xenopus laevis oocytes (XO) and Chinese hamster ovary (CHO) cells. Drug uptake was measured by flameless atomic absorption of platinum. Rat Oatp1-or rat Ntcp-transfected CHO cells were able to take up Bamets, but not cisplatin, severalfold more efficiently than wild-type cells. This uptake was enhanced by butyrate-induced expression of both carriers. Uptake of both Bamets by Ntcp-transfected CHO cells was stimulated by extracellular sodium. The amount of Bamets, but not cisplatin, taken up by XO was enhanced when expressing OATP-A, OATP-C, NTCP, OCT1, or OCT2, a nonhepatic OCT isoform used for comparative purposes. Bamet uptake by XO was inhibited by known substrates of these carriers (glycocholate for NTCP and OATP-C, ouabain for OATP-A, and quinine for OCT1 and OCT2). Drug uptake versus substrate concentration revealed saturation kinetics (K m was in the 8 -58 M range), with the following order of efficiency of transport (V max / K m ) for Bamet-R2: OATP-C Ͼ OCT2 Ͼ OATP-A Ͼ NTCP Ͼ OCT1; and the following order of efficiency of transport for Bamet-UD2: OATP-C Ͼ OCT2 Ͼ OATP-A Ͼ OCT1 Ͼ NTCP. Increasing the generation of cationic forms of Bamets by incubation in the absence of chloride increased drug uptake by OATP-A, OCT1, and OCT2 but reduced that achieved by NTCP and OATP-C. These results suggest a role for carriers of organic anions and cations in Bamet-R2 and Bamet-UD2 uptake, which may determine their ability to accumulate in liver tumor cells and/or be taken up and efficiently excreted by hepatocytes.

Aims: Therapeutic drug monitoring (TDM) of trough serum infliximab concentrations has been mainly used in case of loss of response in patients with inflammatory bowel disease (IBD). The aim of this study was to evaluate the effectiveness and safety of a multidisciplinary early proactive TDM (mep-TDM) programme for dose adjustment. Methods: A 3-year prospective study was conducted based on a sample of 81 patients who started treatment and were subsequently subjected to mep-TDM with the first control at week 14. Data of a historical control group of 72 patients treated with infliximab and managed with empirical dosing were included. Effectiveness variables were treatment failure, IBD-related surgery and IBD-related hospitalization. Safety variables were serious infusion reactions (SIRs) and adverse reactions. Cox regression was used for survival analysis. Results: In the mep-TDM study group, compared to the control group, there was a significant reduction in the risk of treatment failure (hazard ratio [HR]: 0.51; 95% confidence interval [CI]: 0.27-0.92; P = .037), IBD-related surgery (HR: 0.14; 95% CI:0.03-0.65; P = .012) and hospitalization (HR: 0.38; 95% CI: 0.17-0.87; P = .022). SIRs were lower in the mep-TDM group (2.5% vs 10.4%; P < .050); the incidence of adverse reactions was similar (3.7% vs 3.9%; p > .999).Conclusion: This study found that compared to empirical dosing, mep-TDM is associated with improved efficacy and safety of infliximab therapy, reduced IBD-related hospitalization and surgery and incidence of SIRs, and increasing long-term durability of treatment effects. K E Y W O R D Sinflammatory bowel diseases, infliximab, personalized medicine, therapeutic drug monitoring