In vitro and physiologically-based pharmacokinetic based assessment of drug-drug interaction potential of canagliflozin.

AIMS: Canagliflozin is a recently approved drug for use in the treatment of type 2 diabetes. The potential for canagliflozin to cause clinical drug-drug interactions (DDIs) was assessed. METHODS: DDI potential of canagliflozin was investigated using in vitro test systems containing drug metabolizing enzymes or transporters. Basic predictive approaches were applied to determine potential interactions in vivo. A physiologically-based pharmacokinetic (PBPK) model was developed and clinical DDI simulations were performed to determine the likelihood of cytochrome P450 (CYP) inhibition by canagliflozin. RESULTS: Canagliflozin was primarily metabolized by uridine 5'-diphospho-glucuronosyltransferase 1A9 and 2B4 enzymes. Canagliflozin was a substrate of efflux transporters (P-glycoprotein, breast cancer resistance protein and multidrug resistance-associated protein-2) but was not a substrate of uptake transporters (organic anion transporter polypeptide isoforms OATP1B1, OATP1B3, organic anion transporters OAT1 and OAT3, and organic cationic transporters OCT1, and OCT2). In inhibition assays, canagliflozin was shown to be a weak in vitro inhibitor (IC50 ) of CYP3A4 (27 µmol l -1 , standard error [SE] 4.9), CYP2C9 (80 µmol l -1 , SE 8.1), CYP2B6 (16 µmol l-1 , SE 2.1), CYP2C8 (75 µmol l -1 , SE 6.4), P-glycoprotein (19.3 µmol l -1 , SE 7.2), and multidrug resistance-associated protein-2 (21.5 µmol l -1 , SE 3.1). Basic models recommended in DDI guidelines (US Food & Drug Administration and European Medicines Agency) predicted moderate to low likelihood of interaction for these CYPs and efflux transporters. PBPK DDI simulations of canagliflozin with CYP probe substrates (simvastatin, S-warfarin, bupropion, repaglinide) did not show relevant interaction in humans since mean areas under the concentration-time curve and maximum plasma concentration ratios for probe substrates with and without canagliflozin and its 95% CIs were within 0.80-1.25. CONCLUSIONS: In vitro DDI followed by a predictive or PBPK approach was applied to determine DDI potential of canagliflozin. Overall, canagliflozin is neither a perpetrator nor a victim of clinically important interactions.

Pharmacokinetic interaction between telaprevir and methadone.

Hepatitis C virus (HCV) antibody is present in most patients enrolled in methadone maintenance programs. Therefore, interactions between the HCV protease inhibitor telaprevir and methadone were investigated. The pharmacokinetics of R- and S-methadone were measured after administration of methadone alone and after 7 days of telaprevir (750 mg every 8 h [q8h]) coadministration in HCV-negative subjects on stable, individualized methadone therapy. Unbound R-methadone was measured in predose plasma samples before and during telaprevir coadministration. Safety and symptoms of opioid withdrawal were evaluated throughout the study. In total, 18 subjects were enrolled; 2 discontinued prior to receiving telaprevir. The minimum plasma concentration in the dosing interval (C(min)), the maximum plasma concentration (Cmax), and the area under the plasma concentration-time curve from h 0 (time of administration) to 24 h postdose (AUC(0-24)) for R-methadone were reduced by 31%, 29%, and 29%, respectively, in the presence of telaprevir. The AUC0-24 ratio of S-methadone/R-methadone was not altered. The median unbound percentage of R-methadone increased by 26% in the presence of telaprevir. The R-methadone median (absolute) unbound C(min) values in the absence (10.63 ng/ml) and presence (10.45 ng/ml) of telaprevir were similar. There were no symptoms of opioid withdrawal and no discontinuations due to adverse events. In summary, exposure to total R-methadone was reduced by approximately 30% in the presence of telaprevir, while the exposure to unbound R-methadone was unchanged. No symptoms of opioid withdrawal were observed. These results suggest that dose adjustment of methadone is not required when initiating telaprevir treatment. (This study has been registered at ClinicalTrials.gov under registration no. NCT00933283.).

Pharmacokinetics of JNJ-73763989 and JNJ-56136379 (Bersacapavir) in Participants With Moderate Hepatic Impairment.

JNJ-73763989 is comprised of 2 short interfering RNAs (siRNAs), JNJ-73763976 and JNJ-73763924, that target hepatitis B virus (HBV) mRNAs for degradation, thereby inhibiting HBV replication. JNJ-56136379 is a capsid assembly modulator that inhibits HBV replication by inducing the formation of empty capsids (CAM-E). In 2 phase 1, open-label, non-randomized, single-center studies, the single-dose pharmacokinetics, safety, and tolerability of JNJ-73763989 or JNJ-56136379 were assessed in participants with moderate hepatic impairment (Child-Pugh Class B) versus participants with normal liver function. Participants in both studies received a single subcutaneous dose of JNJ-73763989 200 mg or oral JNJ-56136379 250 mg, followed by an evaluation of plasma pharmacokinetic parameters and safety assessments. Plasma exposure to JNJ-73763976, JNJ-73763924, and JNJ-56136379 was 1.3- to 1.4-, 1.8- to 2.2-, and 1.1- to 1.3-fold higher in participants with moderate hepatic impairment versus participants with normal liver function; however, these increases were not considered clinically relevant. Both drugs were well tolerated and safe, with 7 (21.9%) participants experiencing 1 or more treatment-emergent adverse events, 3 of which were related to JNJ-56136379. Overall, the plasma exposures of JNJ-73763989 and JNJ-56136379 were higher in participants with moderate hepatic impairment, but both were well tolerated. Further studies are needed to evaluate the effect of hepatic impairment under multiple-dose administration.

Intestinal organoids as an in vitro platform to characterize disposition, metabolism, and safety profile of small molecules.

Intestinal organoids derived from LGR5+ adult stem cells allow for long-term culturing, more closely resemble human physiology than traditional intestinal models, like Caco-2, and have been established for several species. Here we evaluated intestinal organoids for drug disposition, metabolism, and safety applications. Enterocyte-enriched human duodenal organoids were cultured as monolayers to enable bidirectional transport studies. 3D enterocyte-enriched human duodenal and colonic organoids were incubated with probe substrates of major intestinal drug metabolizing enzymes (DMEs). To distinguish human intestinal toxic (high incidence of diarrhea in clinical trials and/or black box warning related to intestinal side effects) from non-intestinal toxic compounds, ATP-based cell viability was used as a readout, and compounds were ranked based on their IC50 values in relation to their 30-times maximal total plasma concentration (Cmax). To assess if rat and dog organoids reproduced the respective in vivo intestinal safety profiles, ATP-based viability was assessed in rat and dog organoids and compared to in vivo intestinal findings when available. Human duodenal monolayers discriminated high and low permeable compounds and demonstrated functional activity for the main efflux transporters Multi drug resistant protein 1 (MDR1, P-glycoprotein P-gp) and Breast cancer resistant protein (BCRP). Human 3D duodenal and colonic organoids also showed metabolic activity for the main intestinal phase I and II DMEs. Organoids derived from specific intestinal segments showed activity differences in line with reported DMEs expression. Undifferentiated human organoids accurately distinguished all but one compound from the test set of non-toxic and toxic drugs. Cytotoxicity in rat and dog organoids correlated with preclinical toxicity findings and observed species sensitivity differences between human, rat, and dog organoids. In conclusion, the data suggest intestinal organoids are suitable in vitro tools for drug disposition, metabolism, and intestinal toxicity endpoints. The possibility to use organoids from different species, and intestinal segment holds great potential for cross-species and regional comparisons.

Prediction of the drug-drug interaction potential of the α1-acid glycoprotein bound, CYP3A4/CYP2C9 metabolized oncology drug, erdafitinib.

Erdafitinib is a potent oral pan-fibroblast growth factor receptor inhibitor being developed as oncology drug for patients with alterations in the fibroblast growth factor receptor pathway. Erdafitinib binds preferentially to α1-acid glycoprotein (AGP) and is primarily metabolized by cytochrome P450 (CYP) 2C9 and 3A4. This article describes a physiologically based pharmacokinetic (PBPK) model for erdafitinib to assess the drug-drug interaction (DDI) potential of CYP3A4 and CYP2C9 inhibitors and CYP3A4/CYP2C9 inducers on erdafitinib pharmacokinetics (PK) in patients with cancer exhibiting higher AGP levels and in populations with different CYP2C9 genotypes. Erdafitinib's DDI potential as a perpetrator for transporter inhibition and for time-dependent inhibition and/or induction of CYP3A was also evaluated. The PBPK model incorporated input parameters from various in vitro and clinical PK studies, and the model was verified using a clinical DDI study with itraconazole and fluconazole. Erdafitinib clearance in the PBPK model consisted of multiple pathways (CYP2C9/3A4, renal, intestinal; additional hepatic clearance), making the compound less susceptible to DDIs. In poor-metabolizing CYP2C9 populations carrying the CYP2C9*3/*3 genotype, simulations shown clinically relevant increase in erdafitinib plasma concentrations. Simulated luminal and enterocyte concentration showed potential risk of P-glycoprotein inhibition with erdafitinib in the first 5 h after dosing, and simulations showed this interaction can be avoided by staggering erdafitinib and digoxin dosing. Other than a simulated ~ 60% exposure reduction with strong CYP3A/2C inducers such as rifampicin, other DDI liabilities were minimal and considered not clinically relevant.

Trifluoromethyl Dihydrothiazine-Based ß-Secretase (BACE1) Inhibitors with Robust Central ß-Amyloid Reduction and Minimal Covalent Binding Burden.

The ß-site amyloid precursor protein cleaving enzyme 1 (BACE1, also known as ß-secretase) is a promising target for the treatment of Alzheimer's disease. A pKa lowering approach over the initial leads was adopted to mitigate hERG inhibition and P-gp efflux, leading to the design of 6-CF3 dihydrothiazine 8 (N-(3-((4S,6S)-2-amino-4-methyl-6-(trifluoromethyl)-5,6-dihydro-4H-1,3-thiazin-4-yl)-4-fluorophenyl)-5-cyanopicolinamide). Optimization of 8 led to the discovery of 15 (N-(3-((4S,6S)-2-amino-4-methyl-6-(trifluoromethyl)-5,6-dihydro-4H-1,3-thiazin-4-yl)-4-fluorophenyl)-5-(fluoromethoxy)pyrazine-2-carboxamide) with an excellent balance of potency, hERG inhibition, P-gp efflux, and metabolic stability. Oral administration of 8 elicited robust Aß reduction in dog even at 0.16 mg/kg. Reflecting the reduced hERG inhibitory activity, no QTc prolongation was observed at high doses. The potential for reactive metabolite formation of 15 was realized in a nucleophile trapping assay using [14 C]-KCN in human liver microsomes. Utilizing covalent binding (CVB) in human hepatocytes and the maximum projected human dosage, the daily CVB burden of 15 was calculated to be at an acceptable value of below 1 mg/day. However, hepatotoxicity was observed when 15 was subjected to a two-week tolerance study in dog, which prevented further evaluation of this compound.

Single-dose pharmacokinetic studies of abiraterone acetate in men with hepatic or renal impairment.

Three open-label, single-dose studies investigated the impact of hepatic or renal impairment on abiraterone acetate pharmacokinetics and safety/tolerability in non-cancer patients. Patients (n = 8 each group) with mild/moderate hepatic impairment or end-stage renal disease (ESRD), and age-, BMI-matched healthy controls received a single oral 1,000 mg abiraterone acetate (tablet dose); while patients (n = 8 each) with severe hepatic impairment and matched healthy controls received 125- and 2,000-mg abiraterone acetate (suspension doses), respectively (systemic exposure of abiraterone acetate suspension is approximately half to that of tablet formulation). Blood was sampled at specified timepoints up to 72 or 96 hours postdose to measure plasma abiraterone concentrations. Abiraterone exposure was comparable between healthy controls and patients with mild hepatic impairment or ESRD, but increased by 4-fold in patients with moderate hepatic impairment. Despite a 16-fold reduction in dose, abiraterone exposure in patients with severe hepatic impairment was about 22% and 44% of the Cmax and AUC∞ of healthy controls, respectively. These results suggest that abiraterone pharmacokinetics were not changed markedly in patients with ESRD or mild hepatic impairment. However, the capacity to eliminate abiraterone was substantially compromised in patients with moderate or severe hepatic impairment. A single-dose administration of abiraterone acetate was well-tolerated.

Fourier fringe processing by use of an interpolated Fourier-transform technique.

Recently a powerful Fourier transform technique was introduced that was able to extract the phase from only one image. However, because the method is based on the two-dimensional Fourier transform, it inherently suffers from leakage effects. A novel procedure is proposed that does not exhibit this distortion. The procedure uses localized information and estimates both the unknown frequencies and the phases of the fringe pattern (using an interpolated fast Fourier transform method). This allows us to demodulate the fringe pattern without any distortion. The proposed technique is validated on both computer simulations and the profile measurements of a tube.