Effect of Upadacitinib on the Pharmacokinetics of Rosuvastatin or Atorvastatin in Healthy Subjects.

This phase 1, 2-part, 2-period, open-label, drug-drug interaction study evaluated the potential for pharmacokinetic interactions between upadacitinib and rosuvastatin, an organic anion transporting polypeptide (OATP) 1B1 and breast cancer resistance protein substrate, or atorvastatin, a cytochrome P450 3A, OATP1B1, and OATP1B3 substrate, in 36 healthy volunteers. During period 1, a single dose of rosuvastatin (5 mg; part 1) or atorvastatin (10 mg; part 2) was administered on day 1, followed by a washout period of 5 days. During period 2, once-daily doses of upadacitinib extended-release (30 mg) were administered on days 1 to 10, and a single dose of rosuvastatin (5 mg; part 1) or atorvastatin (10 mg; part 2) was administered 1 hour after the upadacitinib dose on day 7. Serial blood samples were collected for assays of drug concentrations. In Part 1, rosuvastatin maximum observed plasma concentration (Cmax ) and area under the plasma concentration-time curve from time 0 to infinity (AUCinf ) were 23% and 33% lower, respectively, when administered with upadacitinib relative to when administered alone. In part 2, atorvastatin Cmax and AUCinf was 11% and 23% lower, respectively, when administered with upadacitinib relative to when administered alone. The Cmax and AUCinf of the active metabolite ortho-hydroxyatorvastatin remained unchanged. Administration of a single 5-mg dose of rosuvastatin or a single 10-mg dose of atorvastatin had no relevant effect on upadacitinib Cmax or area under the plasma concentration-time curve. These results demonstrated that upadacitinib has no clinically relevant effect on the pharmacokinetics of rosuvastatin and atorvastatin or on substrates transported by OATP1B or breast cancer resistance protein.

Evaluation of the Effects of Repeat-Dose Dabrafenib on the Single-Dose Pharmacokinetics of Rosuvastatin (OATP1B1/1B3 Substrate) and Midazolam (CYP3A4 Substrate).

Dabrafenib is an oral BRAF kinase inhibitor approved for the treatment of various BRAF V600 mutation-positive solid tumors. In vitro observations suggesting cytochrome P450 (CYP) 3A induction and organic anion transporting polypeptide (OATP) inhibition prompted us to evaluate the effect of dabrafenib 150 mg twice daily on the pharmacokinetics of midazolam 3 mg (CYP3A substrate) and rosuvastatin 10 mg (OATP1B1/1B3 substrate) in a clinical phase 1, open-label, fixed-sequence study in patients with BRAF V600 mutation-positive tumors. Repeat dabrafenib dosing resulted in a 2.56-fold increase in rosuvastatin maximum observed concentration (Cmax ), an earlier time to Cmax , but only a 7% increase in area under the concentration-time curve from time 0 (predose) extrapolated to infinite time. Midazolam Cmax and AUC extrapolated to infinite time decreased by 47% and 65%, respectively, with little effect on time to Cmax . No new safety findings were reported. Exposure of drugs that are CYP3A4 substrates is likely to decrease when coadministered with dabrafenib. Concentrations of medicinal products that are sensitive OATP1B1/1B3 substrates may increase during the absorption phase.

Effect of Pharmacogenetic Testing for Statin Myopathy Risk vs Usual Care on Blood Cholesterol: A Randomized Clinical Trial.

Importance: Nonadherence to statin guidelines is common. The solute carrier organic anion transporter family member 1B1 (SLCO1B1) genotype is associated with simvastatin myopathy risk and is proposed for clinical implementation. The unintended harms of using pharmacogenetic information to guide pharmacotherapy remain a concern for some stakeholders. Objective: To determine the impact of delivering SLCO1B1 pharmacogenetic results to physicians on the effectiveness of atherosclerotic cardiovascular disease (ASCVD) prevention (measured by low-density lipoprotein cholesterol [LDL-C] levels) and concordance with prescribing guidelines for statin safety and effectiveness. Design, Setting, and Participants: This randomized clinical trial was performed from December 2015 to July 2019 at 8 primary care practices in the Veterans Affairs Boston Healthcare System. Participants included statin-naive patients with elevated ASCVD risk. Data analysis was performed from October 2019 to September 2020. Interventions: SLCO1B1 genotyping and results reporting to primary care physicians at baseline (intervention group) vs after 1 year (control group). Main Outcomes and Measures: The primary outcome was the 1-year change in LDL-C level. The secondary outcomes were 1-year concordance with American College of Cardiology-American Heart Association and Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines for statin therapy and statin-associated muscle symptoms (SAMS). Results: Among 408 patients (mean [SD] age, 64.1 [7.8] years; 25 women [6.1%]), 193 were randomized to the intervention group and 215 were randomized to the control group. Overall, 120 participants (29%) had a SLCO1B1 genotype indicating increased simvastatin myopathy risk. Physicians offered statin therapy to 65 participants (33.7%) in the intervention group and 69 participants (32.1%) in the control group. Compared with patients whose physicians did not know their SLCO1B1 results at baseline, patients whose physicians received the results had noninferior reductions in LDL-C at 12 months (mean [SE] change in LDL-C, -1.1 [1.2] mg/dL in the intervention group and -2.2 [1.3] mg/dL in the control group; difference, -1.1 mg/dL; 90% CI, -4.1 to 1.8 mg/dL; P < .001 for noninferiority margin of 10 mg/dL). The proportion of patients with American College of Cardiology-American Heart Association guideline-concordant statin prescriptions in the intervention group was noninferior to that in the control group (12 patients [6.2%] vs 14 patients [6.5%]; difference, -0.003; 90% CI, -0.038 to 0.032; P < .001 for noninferiority margin of 15%). All patients in both groups were concordant with CPIC guidelines for safe statin prescribing. Physicians documented 2 and 3 cases of SAMS in the intervention and control groups, respectively, none of which was associated with a CPIC guideline-discordant prescription. Among patients with a decreased or poor SLCO1B1 transporter function genotype, simvastatin was prescribed to 1 patient in the control group but none in the intervention group. Conclusions and Relevance: Clinical testing and reporting of SLCO1B1 results for statin myopathy risk did not result in poorer ASCVD prevention in a routine primary care setting and may have been associated with physicians avoiding simvastatin prescriptions for patients at genetic risk for SAMS. Such an absence of harm should reassure stakeholders contemplating the clinical use of available pharmacogenetic results. Trial Registration: ClinicalTrials.gov Identifier: NCT02871934.

Precursor-Directed Biosynthesis and Fluorescence Labeling of Clickable Microcystins.

Microcystins, cyclic nonribosomal heptapeptides, are the most well-known cyanobacterial toxins. They are exceptionally well studied, but open questions remain concerning their physiological role for the producing microorganism or their suitability as lead compounds for anticancer drug development. One means to study specialized metabolites in more detail is the introduction of functional groups that make a compound amenable for bioorthogonal, so-called click reactions. Although it was reported that microcystins cannot be derivatized by precursor-directed biosynthesis, we successfully used this approach to prepare clickable microcystins. Supplementing different azide- or terminal alkyne containing amino acid analogues into the cultivation medium of microcystin-producing cyanobacteria strains, we found that these strains differ strongly in their substrate acceptance. Exploiting this flexibility, we generated more than 40 different clickable microcystins. We conjugated one of these derivatives with a fluorogenic dye and showed that neither incorporation of the unnatural amino acid analogue nor attachment of the fluorescent label significantly affects the cytotoxicity against cell lines expressing the human organic anion transporting polypeptides 1B1 or 1B3. Using time-lapse microscopy, we observed that the fluorescent microcystin is rapidly taken up into eukaryotic cells expressing these transporters.

Complex DDI by Fenebrutinib and the Use of Transporter Endogenous Biomarkers to Elucidate the Mechanism of DDI.

Mechanistic understanding of complex clinical drug-drug interactions (DDIs) with potential involvement of multiple elimination pathways has been challenging, especially given the general lack of specific probe substrates for transporters. Here, we conducted a clinical DDI study to evaluate the interaction potential of fenebrutinib using midazolam (MDZ; CYP3A), simvastatin (CYP3A and OATP1B), and rosuvastatin (BCRP and OATP1B) as probe substrates. Fenebrutinib (200 mg) increased the area under the curve (AUC) of these probe substrates twofold to threefold. To evaluate the mechanism of the observed DDIs, we measured the concentration of coproporphyrin I (CP-I) and coproporphyrin III (CP-III), endogenous biomarkers of OATP1B. There was no change in CP-I or CP-III levels with fenebrutinib, suggesting that the observed DDIs were caused by inhibition of CYP3A and BCRP rather than OATP1B, likely due to increased bioavailability. This is the first published account using an endogenous transporter biomarker to understand the mechanism of complex DDIs involving multiple elimination pathways.

Physiologically Based Pharmacokinetic Models for Prediction of Complex CYP2C8 and OATP1B1 (SLCO1B1) Drug-Drug-Gene Interactions: A Modeling Network of Gemfibrozil, Repaglinide, Pioglitazone, Rifampicin, Clarithromycin and Itraconazole.

BACKGROUND: Drug-drug interactions (DDIs) and drug-gene interactions (DGIs) pose a serious health risk that can be avoided by dose adaptation. These interactions are investigated in strictly controlled setups, quantifying the effect of one perpetrator drug or polymorphism at a time, but in real life patients frequently take more than two medications and are very heterogenous regarding their genetic background. OBJECTIVES: The first objective of this study was to provide whole-body physiologically based pharmacokinetic (PBPK) models of important cytochrome P450 (CYP) 2C8 perpetrator and victim drugs, built and evaluated for DDI and DGI studies. The second objective was to apply these models to describe complex interactions with more than two interacting partners. METHODS: PBPK models of the CYP2C8 and organic-anion-transporting polypeptide (OATP) 1B1 perpetrator drug gemfibrozil (parent-metabolite model) and the CYP2C8 victim drugs repaglinide (also an OATP1B1 substrate) and pioglitazone were developed using a total of 103 clinical studies. For evaluation, these models were applied to predict 34 different DDI studies, establishing a CYP2C8 and OATP1B1 PBPK DDI modeling network. RESULTS: The newly developed models show a good performance, accurately describing plasma concentration-time profiles, area under the plasma concentration-time curve (AUC) and maximum plasma concentration (Cmax) values, DDI studies as well as DGI studies. All 34 of the modeled DDI AUC ratios (AUC during DDI/AUC control) and DDI Cmax ratios (Cmax during DDI/Cmax control) are within twofold of the observed values. CONCLUSIONS: Whole-body PBPK models of gemfibrozil, repaglinide, and pioglitazone have been built and qualified for DDI and DGI prediction. PBPK modeling is applicable to investigate complex interactions between multiple drugs and genetic polymorphisms.

Pazopanib interacts with irinotecan by inhibiting UGT1A1-mediated glucuronidation, but not OATP1B1-mediated hepatic uptake, of an active metabolite SN-38.

PURPOSE: Pazopanib is an orally active, multi-targeted tyrosine kinase inhibitor. A previous phase I study demonstrated that coadministration of pazopanib with irinotecan increases the area under the plasma concentration-time curve (AUC) for SN-38, an active metabolite of irinotecan. To clarify the possible mechanism underlying that drug-drug interaction, we investigated the potential for pazopanib to inhibit UDP-glucuronosyltransferase (UGT)1A1 and organic anion-transporting polypeptide (OATP)1B1, which are involved in detoxification and hepatic uptake of SN-38, respectively. METHODS: Human liver microsomes (HLMs) and recombinant human UGT1A1, and HEK293 cells stably transfected with OATP1B1 were used to evaluate the inhibitory effects of pazopanib against glucuronidation, and hepatic uptake of SN-38, respectively. Kinetic analysis was performed to estimate inhibition constants, which were corrected for non-specific binding to enzyme sources (Ki,u values). RESULTS: Concentration-dependent inhibition of SN-38 glucuronidation was observed in the HLMs and recombinant human UGT1A1 experiments: Pazopanib noncompetitively inhibited SN-38 glucuronidation by HLMs (Ki,u = 1.6 ± 0.05 µM) and recombinant human UGT1A1 (Ki,u = 0.69 ± 0.02 µM). Pazopanib-induced increases in SN-38 AUC estimated using Ki,u values were comparable to those observed in patients of the phase I study who received both irinotecan and pazopanib. Such results suggest that the drug-drug interaction is at least partially mediated by inhibition of UGT1A1. In contrast, pazopanib did not inhibit OATP1B1-mediated SN-38 uptake at concentrations up to 60 µM. CONCLUSIONS: Results showed that pazopanib inhibits UGT1A1-mediated SN-38 glucuronidation, but not OATP1B1-mediated SN-38 uptake.

SLCO1B1 genetic variation and hormone therapy in menopausal women.

OBJECTIVE: Response to menopausal hormone therapy (MHT) shows individual variation. SLCO1B1 encodes the OATP1B1 transporter expressed in the liver that transports many endogenous substances, including estrone sulfate, from the blood into hepatocytes. This study evaluated the relationship between genetic variation in SLCO1B1 and response to MHT in women enrolled in the Kronos Early Estrogen Prevention Study (KEEPS) at Mayo Clinic, Rochester, MN. METHODS: KEEPS participants were randomized to oral conjugated equine estrogen (n = 33, oCEE), transdermal 17ß-estradiol (n = 33, tE2), or placebo (n = 34) for 48 months. Menopausal symptoms (hot flashes, night sweats, insomnia, palpitations) were self-reported before treatment and at 48 months. Estrone (E1), E2, and sulfated conjugates (E1S, E2S) were measured using high-performance liquid chromatography-tandem mass spectrometry. SLCO1B1 rs4149056 (c.521T>C, p.Val174Ala) was genotyped using a TaqMan assay. RESULTS: After adjusting for treatment, there was a significant association between the SLCO1B1 rs4149056 TT genotype (encoding normal function transporter) and lower E1S, E1S/E1, and E2S (P = 0.032, 0.010, and 0.008, respectively) compared with women who were heterozygous (TC) or homozygous (CC) for the reduced function allele. The interactions between genotype, treatment, and E2S concentration were stronger in women assigned to tE2 (P = 0.013) than the women taking oCEE (P = 0.056). Among women assigned to active treatment, women with the CT genotype showed a significantly greater decrease in night sweats (P = 0.041) than those with the TT genotype. CONCLUSIONS: Individual variation in sulfated estrogens is explained, in part, by genetic variation in SLCO1B1. Bioavailability of sulfated estrogens may contribute to relief of night sweats.

Cooperative inhibitory effects of uremic toxins and other serum components on OATP1B1-mediated transport of SN-38.

PURPOSE: Half-life of SN-38, an active metabolite of irinotecan, remarkably increases in patients with end-stage kidney disease (ESKD), even though SN-38 is excreted in bile. Uremic toxins (UTs), which accumulate in the serum of ESKD patients, were reported to inhibit organic anion-transporting polypeptide (OATP) 1B1-mediated uptake of SN-38; however, the relevance of this finding in a clinical setting is unknown. This study focused on cooperative effects of serum components and UTs on OATP1B1-mediated transport of SN-38. METHODS: Uptake of SN-38 by OATP1B1 was evaluated using cells stably expressing OATP1B1. Serum was obtained from > 400 ESKD patients undergoing hemodialysis. Deproteinized serum was combined with human serum albumin (HSA) to explore the effects of albumin-bound and unbound serum compounds. RESULTS: Uptake clearance of SN-38 in OATP1B1 cells decreased by 40% in the presence of uremic serum residue with albumin compared to that in the presence of normal serum residue. Additional UTs (3-carboxy-4-methyl-5-propyl-2-furanpropionic acid, hippuric acid, indole-3-acetic acid, and 3-indoxyl sulfate) combined with normal serum residue in HSA decreased OATP1B1-mediated SN-38 transport by 32.1% compared to that in the presence of normal serum residue. The inhibitory effect of albumin-unbound fraction with UTs and normal serum residue was comparable to that of uremic serum residue, with an uptake decrease of 17.2% compared to that reported in the presence of normal serum residue. CONCLUSIONS: Hepatic uptake of SN-38 via OATP1B1 decreases in ESKD patients through cooperative inhibitory effects of UTs and serum components.

Development of a high-throughput mass spectrometry based analytical method to support an in vitro OATP1B1 inhibition screening assay.

RATIONALE: It is well known that the organic anion transporting polypeptide 1B1 (OATP1B1) plays a major role in the hepatic uptake of a range of drugs. To this end, it is pivotal that the potential for new molecular entities (NMEs) to inhibit OATP1B1 activity be assessed during early drug discovery. The work reported herein describes the development of a high-throughput analytical method to measure the clinically relevant probe substrate, pitavastatin, for the in vitro assessment of OATP1B1 inhibition. METHODS: Development of an analytical method capable of very fast throughput was crucial for the success of this assay and was accomplished using a system which combines direct, on-line solid-phase extraction (SPE) with highly sensitive, label-free tandem mass spectrometry (MS/MS)-based detection. Mass spectrometry analysis of pitavastatin, along with the stable isotopically labeled internal standard d5-pitavastatin, was conducted using positive electrospray ionization (ESI) in selected reaction monitoring (SRM) mode. RESULTS: The on-line SPE-MS/MS platform demonstrated similar sensitivity, selectivity, reproducibility, linearity and robustness to existing methodologies while achieving analytical cycle times of 10.4 seconds per well. Sensitivity exceeded what was necessary for our assay conditions, with a determined lower limit of quantification (LLOQ) for pitavastatin of 10 pM (picomolar) in assay matrix. Furthermore, the potency of multiple reference compounds was shown to be within 2-fold of IC50 values generated from liquid chromatography (LC)/MS/MS-based literature values. CONCLUSIONS: A very fast and robust analytical method was successfully developed for the measurement of the clinically relevant OATP1B1 substrate, pitavastatin. The successful development and implementation of this very important early liability screen has helped to facilitate judicious lead candidate progression and will ultimately help build a greater understanding of OATP1B1-NME interactions, in general. Copyright © 2016 John Wiley & Sons, Ltd.

Elucidating rifampin's inducing and inhibiting effects on glyburide pharmacokinetics and blood glucose in healthy volunteers: unmasking the differential effects of enzyme induction and transporter inhibition for a drug and its primary metabolite.

The effects of single doses of intravenous (IV) ciprofloxacin and rifampin and of multiple doses of rifampin on glyburide exposure and blood glucose levels were investigated in nine healthy volunteers. A single IV dose of rifampin significantly increased the area under the concentration-time curve (AUC) of glyburide and its metabolite. Blood glucose levels were significantly lower than those observed after dosing with glyburide alone. Multiple doses of rifampin induced an increase in liver enzyme levels, leading to a marked decrease in glyburide exposure and blood glucose levels. When IV rifampin was administered after multiple doses of rifampin, the inhibition of hepatic uptake transporters masked the induction effect; however, the relative changes in AUC for glyburide and its hydroxyl metabolite were similar to those seen under noninduced conditions. The studies reported here demonstrate how measurements of the levels of both the parent drug and its primary metabolite are useful in unmasking simultaneous drug-drug induction and inhibition effects and in characterizing enzymatic vs. transporter mechanisms.

Uptake of ursodeoxycholate and its conjugates by human hepatocytes: role of Na(+)-taurocholate cotransporting polypeptide (NTCP), organic anion transporting polypeptide (OATP) 1B1 (OATP-C), and oatp1B3 (OATP8).

Ursodeoxycholate (UDCA) is widely used for the treatment of cholestatic liver disease. After oral administration, UDCA is absorbed, taken up efficiently by hepatocytes, and conjugated mainly with glycine to form glycoursodeoxycholate (GUDC) or partly with taurine to form tauroursodeoxycholate (TUDC), which undergo enterohepatic circulation. In this study, to check whether three basolateral transporters--Na(+)-taurocholate cotransporting polypeptide (NTCP, SLC10A1), organic anion transporting polypeptide (OATP) 1B1 (OATP-C), and OATP1B3 (OATP8)-mediate uptake of UDCA, GUDC, and TUDC by human hepatocytes, we investigated their transport properties using transporter-expressing HEK293 cells and human cryopreserved hepatocytes. TUDC and GUDC could be taken up via human NTCP, OATP1B1, and OATP1B3, whereas UDCA could be transported significantly by NTCP, but not OATP1B1 and OATP1B3 in our expression systems. We observed a time-dependent and saturable uptake of UDCA and its conjugates by human cryopreserved hepatocytes, and more than half of the overall uptake involved a saturable component. Kinetic analyses revealed that the contribution of Na(+)-dependent and -independent pathways to the uptake of UDCA or TUDC was very similar, while the Na(+)-independent uptake of GUDC was predominant. These results suggest that UDCA and its conjugates are taken up by both multiple saturable transport systems and nonsaturable transport in human liver with different contributions. These results provide an explanation for the efficient hepatic clearance of UDCA and its conjugates in patients receiving UDCA therapy.

Gemfibrozil and its glucuronide inhibit the organic anion transporting polypeptide 2 (OATP2/OATP1B1:SLC21A6)-mediated hepatic uptake and CYP2C8-mediated metabolism of cerivastatin: analysis of the mechanism of the clinically relevant drug-drug interaction between cerivastatin and gemfibrozil.

A serious pharmacokinetic interaction between cerivastatin (CER) and gemfibrozil (GEM) has been reported. In the present study, we examined the inhibitory effects of GEM and its metabolites, M3 and gemfibrozil 1-O-beta-glucuronide (GEM-1-O-glu), on the uptake of CER by human organic anion transporting polypeptide 2 (OATP2)-expressing cells and its metabolism in cytochrome P450 expression systems. Uptake studies showed that GEM and GEM-1-O-glu significantly inhibited the OATP2-mediated uptake of CER with IC(50) values of 72 and 24 microM, respectively. They also inhibited the CYP2C8-mediated metabolism of CER with IC(50) values of 28 and 4 microM, respectively, whereas M3 had no effects. GEM and GEM-1-O-glu minimally inhibited the CYP3A4-mediated metabolism of CER. The IC(50) values of GEM and GEM-1-O-glu for the uptake and the metabolism of CER obtained in the present study were lower than their total, and not unbound, plasma concentrations. However, considering the possibly concentrated high unbound concentrations of GEM-1-O-glu in the liver and its relatively larger plasma unbound fraction compared with GEM itself, the glucuronide inhibition of the CYP2C8-mediated metabolism of CER appears to be the main mechanism for the clinically relevant drug-drug interaction. Previously reported clinical drug interaction studies showing that coadministration of GEM with pravastatin or pitavastatin, both of which are known to be cleared from the plasma by the uptake transporters in the liver, only minimally (less than 2-fold) increased the area under the plasma concentration-time curve of these statins, also supported our present conclusion.