Time-in-therapeutic-range defined warfarin and direct oral anticoagulants in atrial fibrillation: a Nationwide Cohort Study.

BACKGROUND: Little is known how individual time-in-therapeutic-range (TTR) impacts the effectiveness and safety of warfarin therapy compared to direct oral anticoagulants (DOACs) in patients with atrial fibrillation (AF). OBJECTIVE: To compare the effectiveness and safety of standard dose DOACs to warfarin in patients with AF, while categorizing warfarin treated patients into quartiles based on their individual TTR. MATERIALS AND METHODS: We conducted a nationwide study including all patients with new-onset AF between 2011 and 2018 in Finland. Hazard ratios (HR) were calculated using Cox regression analysis with the inverse probability of treatment weighted method to assess the risks of ischaemic stroke (IS), intracranial haemorrhage (ICH) and mortality for users of apixaban (n = 12,426), dabigatran (n = 4545), rivaroxaban (n = 12,950) and warfarin (n = 43,548). RESULTS: The median TTR for warfarin users was 72%. Compared to the second best TTR quartile (reference), the risk of IS was higher in the two poorest TTR quartiles, and lower in the best TTR quartile and on rivaroxaban [2.35 (95% confidence interval, 1.85-2.85), 1.44 (1.18-1.75), 0.60 (0.47-0.77) and 0.72 (0.56-0.92)]. These differences were non-significant for apixaban and dabigatran. HR of ICH was 6.38 (4.88-8.35) and 1.87 (1.41-2.49) in the two poorest TTR groups, 1.44 (1.02-1.93) on rivaroxaban, and 0.58 (0.40-0.85) in the best TTR group compared to the reference group. Mortality was higher in the two poorest TTR groups and lowest in the best TTR group. CONCLUSIONS: The outcome was unsatisfactory in the two lowest TTR quartiles - in half of the patients treated with warfarin. The differences between the high TTR groups and standard dose DOACs were absent or modest.

Non-targeted metabolomics for the identification of plasma metabolites associated with organic anion transporting polypeptide 1B1 function.

Our aim was to evaluate biomarkers for organic anion transporting polypeptide 1B1 (OATP1B1) function using a hypothesis-free metabolomics approach. We analyzed fasting plasma samples from 356 healthy volunteers using non-targeted metabolite profiling by liquid chromatography high-resolution mass spectrometry. Based on SLCO1B1 genotypes, we stratified the volunteers to poor, decreased, normal, increased, and highly increased OATP1B1 function groups. Linear regression analysis, and random forest (RF) and gradient boosted decision tree (GBDT) regressors were used to investigate associations of plasma metabolite features with OATP1B1 function. Of the 9152 molecular features found, 39 associated with OATP1B1 function either in the linear regression analysis (p < 10-5) or the RF or GBDT regressors (Gini impurity decrease > 0.01). Linear regression analysis showed the strongest associations with two features identified as glycodeoxycholate 3-O-glucuronide (GDCA-3G; p = 1.2 × 10-20 for negative and p = 1.7 × 10-19 for positive electrospray ionization) and one identified as glycochenodeoxycholate 3-O-glucuronide (GCDCA-3G; p = 2.7 × 10-16). In both the RF and GBDT models, the GCDCA-3G feature showed the strongest association with OATP1B1 function, with Gini impurity decreases of 0.40 and 0.17. In RF, this was followed by one GDCA-3G feature, an unidentified feature with a molecular weight of 809.3521, and the second GDCA-3G feature. In GBDT, the second and third strongest associations were observed with the GDCA-3G features. Of the other associated features, we identified with confidence two representing lysophosphatidylethanolamine 22:5. In addition, one feature was putatively identified as pregnanolone sulfate and one as pregnenolone sulfate. These results confirm GCDCA-3G and GDCA-3G as robust OATP1B1 biomarkers in human plasma.

Genome-Wide Association Study of Atorvastatin Pharmacokinetics: Associations With SLCO1B1, UGT1A3, and LPP.

In a genome-wide association study of atorvastatin pharmacokinetics in 158 healthy volunteers, the SLCO1B1 c.521T>C (rs4149056) variant associated with increased area under the plasma concentration-time curve from time zero to infinity (AUC0-∞) of atorvastatin (P = 1.2 × 10-10), 2-hydroxy atorvastatin (P = 4.0 × 10-8), and 4-hydroxy atorvastatin (P = 2.9 × 10-8). An intronic LPP variant, rs1975991, associated with reduced atorvastatin lactone AUC0-∞ (P = 3.8 × 10-8). Three UGT1A variants linked with UGT1A3*2 associated with increased 2-hydroxy atorvastatin lactone AUC0-∞ (P = 3.9 × 10-8). Furthermore, a candidate gene analysis including 243 participants suggested that increased function SLCO1B1 variants and decreased activity CYP3A4 variants affect atorvastatin pharmacokinetics. Compared with individuals with normal function SLCO1B1 genotype, atorvastatin AUC0-∞ was 145% (90% confidence interval: 98-203%; P = 5.6 × 10-11) larger in individuals with poor function, 24% (9-41%; P = 0.0053) larger in those with decreased function, and 41% (16-59%; P = 0.016) smaller in those with highly increased function SLCO1B1 genotype. Individuals with intermediate metabolizer CYP3A4 genotype (CYP3A4*2 or CYP3A4*22 heterozygotes) had 33% (14-55%; P = 0.022) larger atorvastatin AUC0-∞ than those with normal metabolizer genotype. UGT1A3*2 heterozygotes had 16% (5-25%; P = 0.017) smaller and LPP rs1975991 homozygotes had 34% (22-44%; P = 4.8 × 10-5) smaller atorvastatin AUC0-∞ than noncarriers. These data demonstrate that genetic variation in SLCO1B1, UGT1A3, LPP, and CYP3A4 affects atorvastatin pharmacokinetics. This is the first study to suggest that LPP rs1975991 may reduce atorvastatin exposure. [Correction added on 6 April, after first online publication: An incomplete sentence ("= 0.017) smaller in heterozygotes for UGT1A3*2 and 34% (22%, 44%; P × 10-5) smaller in homozygotes for LPP noncarriers.") has been corrected in this version.].

The effect of hydroxychloroquine on cholesterol synthesis depends on the profile of cholesterol metabolism. A controlled clinical study.

Background and aims: Hydroxychloroquine (HCQ) has a variable effect on cholesterol synthesis. To clarify this, we assessed the effect of HCQ on the cholesterol-synthesis pathway in individuals with low and high cholesterol absorption efficiency. Method: A total of 53 acute myocardial infarction patients with a constant statin dose randomized to receive HCQ or placebo for six months in a double-blind manner, were classified further into low (n = 26) and high (n = 27) cholesterol absorbers based on the median baseline serum cholestanol level. Serum lipids and biomarkers of cholesterol synthesis (squalene, lanosterol, zymostenol, desmosterol, and lathosterol) and absorption efficiency (sitosterol and cholestanol), were measured at baseline and one-, six-, and 12-month follow-up visits. Results: In low cholesterol absorbers, serum cholesterol concentration and cholesterol synthesis and absorption biomarkers did not differ between the HCQ and placebo groups. At one month, high cholesterol absorbers with HCQ had lower serum cholesterol concentration and serum lanosterol to cholesterol ratio in comparison to the placebo group (HCQ 3.18 ± 0.62 vs. placebo 3.71 ± 0.65, p = 0.042, and HCQ 10.4 ± 2.55 vs. placebo 13.1 ± 2.36, p = 0.008, respectively). At 12 months, serum desmosterol to cholesterol ratio was lower in HCQ users (HCQ 47.1 ± 7.08 vs. placebo 59.0 ± 13.1, p = 0.011). Conclusions: HCQ affects the cholesterol-synthesis pathway in high cholesterol absorbers. It reduces serum lanosterol and desmosterol ratios and consequently serum cholesterol concentration possibly by inhibiting the activity of lanosterol synthase as described earlier in vitro studies. Trial registration: ClinicalTrials.gov Identifier: NCT02648464.

Solanidine is a sensitive and specific dietary biomarker for CYP2D6 activity.

BACKGROUND: Individual assessment of CYP enzyme activities can be challenging. Recently, the potato alkaloid solanidine was suggested as a biomarker for CYP2D6 activity. Here, we aimed to characterize the sensitivity and specificity of solanidine as a CYP2D6 biomarker among Finnish volunteers with known CYP2D6 genotypes. RESULTS: Using non-targeted metabolomics analysis, we identified 9152 metabolite features in the fasting plasma samples of 356 healthy volunteers. Machine learning models suggested strong association between CYP2D6 genotype-based phenotype classes with a metabolite feature identified as solanidine. Plasma solanidine concentration was 1887% higher in genetically poor CYP2D6 metabolizers (gPM) (n = 9; 95% confidence interval 755%, 4515%; P = 1.88 × 10-11), 74% higher in intermediate CYP2D6 metabolizers (gIM) (n = 89; 27%, 138%; P = 6.40 × 10-4), and 35% lower in ultrarapid CYP2D6 metabolizers (gUM) (n = 20; 64%, - 17%; P = 0.151) than in genetically normal CYP2D6 metabolizers (gNM; n = 196). The solanidine metabolites m/z 444 and 430 to solanidine concentration ratios showed even stronger associations with CYP2D6 phenotypes. Furthermore, the areas under the receiver operating characteristic and precision-recall curves for these metabolic ratios showed equal or better performances for identifying the gPM, gIM, and gUM phenotype groups than the other metabolites, their ratios to solanidine, or solanidine alone. In vitro studies with human recombinant CYP enzymes showed that solanidine was metabolized mainly by CYP2D6, with a minor contribution from CYP3A4/5. In human liver microsomes, the CYP2D6 inhibitor paroxetine nearly completely (95%) inhibited the metabolism of solanidine. In a genome-wide association study, several variants near the CYP2D6 gene associated with plasma solanidine metabolite ratios. CONCLUSIONS: These results are in line with earlier studies and further indicate that solanidine and its metabolites are sensitive and specific biomarkers for measuring CYP2D6 activity. Since potato consumption is common worldwide, this biomarker could be useful for evaluating CYP2D6-mediated drug-drug interactions and to improve prediction of CYP2D6 activity in addition to genotyping.

Screening of 16 major drug glucuronides for time-dependent inhibition of nine drug-metabolizing CYP enzymes - detailed studies on CYP3A inhibitors.

Time-dependent inhibition of cytochrome P450 (CYP) enzymes has been observed for a few glucuronide metabolites of clinically used drugs. Here, we investigated the inhibitory potential of 16 glucuronide metabolites towards nine major CYP enzymes in vitro. Automated substrate cocktail methods were used to screen time-dependent inhibition of CYP1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2J2 and 3A in human liver microsomes. Seven glucuronides (carvedilol ß-D-glucuronide, diclofenac acyl-ß-D-glucuronide, 4-hydroxyduloxetine ß-D-glucuronide, ezetimibe phenoxy-ß-D-glucuronide, raloxifene 4'-glucuronide, repaglinide acyl-ß-D-glucuronide and valproic acid ß-D-glucuronide) caused NADPH- and time-dependent inhibition of at least one of the CYPs investigated, including CYP2A6, CYP2C19 and CYP3A. In more detailed experiments, we focused on the glucuronides of carvedilol and diclofenac, which inhibited CYP3A. Carvedilol ß-D-glucuronide showed weak time-dependent inhibition of CYP3A, but the parent drug carvedilol was found to be a more potent inhibitor of CYP3A, with the half-maximal inhibitor concentration (IC50) decreasing from 7.0 to 1.1 µM after a 30-min preincubation with NADPH. The maximal inactivation constant (kinact) and the inhibitor concentration causing half of kinact (KI) for CYP3A inactivation by carvedilol were 0.051 1/min and 1.8 µM, respectively. Diclofenac acyl-ß-D-glucuronide caused time-dependent inactivation of CYP3A at high concentrations, with a 4-fold IC50 shift (from 400 to 98 µM after a 30-min preincubation with NADPH) and KI and kinact values of >2,000 µM and >0.16 1/min. In static predictions, carvedilol caused significant (>1.25-fold) increase in the exposure of the CYP3A substrates midazolam and simvastatin. In conclusion, we identified several glucuronide metabolites with CYP inhibitory properties. Based on detailed experiments, the inactivation of CYP3A by carvedilol may cause clinically significant drug-drug interactions.

Ticagrelor Increases Exposure to the Breast Cancer Resistance Protein Substrate Rosuvastatin.

Ticagrelor and rosuvastatin are often used concomitantly after atherothrombotic events. Several cases of rhabdomyolysis during concomitant ticagrelor and rosuvastatin have been reported, suggesting a drug-drug interaction. We showed recently that ticagrelor inhibits breast cancer resistance protein (BCRP) and organic anion transporting polypeptide (OATP) 1B1, 1B3, and 2B1-mediated rosuvastatin transport in vitro. The aim of this study was to investigate the effects of ticagrelor on rosuvastatin pharmacokinetics in humans. In a randomized, crossover study, 9 healthy volunteers ingested a single dose of 90 mg ticagrelor or placebo, followed by a single 10 mg dose of rosuvastatin 1 hour later. Ticagrelor 90 mg or placebo were additionally administered 12, 24, and 36 hours after their first dose. Ticagrelor increased rosuvastatin area under the plasma concentration-time curve (AUC) and peak plasma concentration 2.6-fold (90% confidence intervals: 1.8-3.8 and 1.7-4.0, P = 0.001 and P = 0.003), and prolonged its half-life from 3.1 to 6.6 hours (P = 0.009). Ticagrelor also decreased the renal clearance of rosuvastatin by 11% (3%-19%, P = 0.032). The N-desmethylrosuvastatin:rosuvastatin AUC0-10h ratio remained unaffected by ticagrelor. Ticagrelor had no effect on the plasma concentrations of the endogenous OATP1B substrates glycodeoxycholate 3-O-glucuronide, glycochenodeoxycholate 3-O-glucuronide, glycodeoxycholate 3-O-sulfate, and glycochenodeoxycholate 3-O-sulfate, or the sodium-taurocholate cotransporting polypeptide substrate taurocholic acid. These data indicate that ticagrelor increases rosuvastatin concentrations more than twofold in humans, probably mainly by inhibiting intestinal BCRP. Because the risk for rosuvastatin-induced myotoxicity increases along with rosuvastatin plasma concentrations, using ticagrelor concomitantly with high doses of rosuvastatin should be avoided.

Drug-related deaths in a university hospital: Comparison to previous decades.

The incidence of fatal adverse drug reactions (ADRs) in hospitals varies widely, and ADRs are often underreported. The impact of medical safety processes is not easily evaluated, and although medical practice changes constantly, little is known about ADR trends. This study concentrated on the current incidence and properties of fatal ADRs occurring in a university hospital and compared the results with two previous studies performed in the same hospital. We investigated retrospectively all 1236 deaths that occurred during 2019 in the Helsinki University Hospital. All the cases were evaluated by a team of experts, and the causality was assessed using the categories by World Health Organization and Uppsala monitoring centre. Suicides were excluded. Among death cases, we identified 65 certain or probable ADR cases (5.3%), representing 0.011% of all hospital admissions. Cytostatics and antithrombotics remained the largest drug classes, with neutropenia or sepsis and bleedings as the most common fatal ADRs. Compared with our earlier studies, warfarin caused less, and direct oral anticoagulants caused more fatal bleedings, reflecting the drug usage among the population. In contrast to earlier studies, contrast media and insulin did not cause any fatal ADRs, which may reflect an improvement in pharmacovigilance awareness among healthcare workers.

Posaconazole-ibrutinib interaction cannot be avoided by staggered dosing: How to optimize ibrutinib dose during posaconazole treatment.

AIMS: Ibrutinib is used in the treatment of certain B-cell malignancies. Due to its CYP3A4-mediated metabolism and highly variable pharmacokinetics, it is prone to potentially harmful drug-drug interactions. METHODS: In a randomized, placebo-controlled, three-phase crossover study, we examined the effect of the CYP3A4-inhibiting antifungal posaconazole on ibrutinib pharmacokinetics. Eleven healthy participants ingested repeated doses of 300 mg of posaconazole either in the morning or in the evening, or placebo. A single dose of ibrutinib (30, 70 or 140 mg, respectively) was administered at 9 AM, 1 or 12 h after the preceding posaconazole/placebo dose. RESULTS: On average, morning posaconazole increased the dose-adjusted geometric mean area under the plasma concentration-time curve from zero to infinity (AUC0-∞ ) and peak plasma concentration (Cmax ) of ibrutinib 9.5-fold (90% confidence interval [CI] 6.3-14.3, P < 0.001) and 8.5-fold (90% CI 5.7-12.8, P < 0.001), respectively, while evening posaconazole increased those 10.3-fold (90% CI 6.7-16.0, P < 0.001) and 8.2-fold (90% CI 5.2-13.2, P < 0.001), respectively. Posaconazole had no significant effect on the half-life of ibrutinib, but substantially reduced the metabolite PCI-45227 to ibrutinib AUC0-∞ ratio. There were no significant differences in ibrutinib pharmacokinetics between morning and evening posaconazole phases. CONCLUSIONS: Posaconazole increases ibrutinib exposure substantially, by about 10-fold. This interaction cannot be avoided by dosing the drugs 12 h apart. In general, a 70-mg daily dose of ibrutinib should not be exceeded during posaconazole treatment to avoid potentially toxic systemic ibrutinib concentrations.

Inhibition of efflux transporters by poly ADP-ribose polymerase inhibitors.

Poly ADP-ribose polymerase (PARP) inhibitors have been approved for the treatment of various cancers. They share a similar mechanism of action but have differences in pharmacokinetic characteristics and potential for drug-drug interactions (DDI). This study evaluated the potential ATP-binding cassette transporter-mediated interactions between PARP inhibitors (niraparib, olaparib and rucaparib) and statins (atorvastatin and rosuvastatin). We studied the inhibitory activity of PARP inhibitors on breast cancer resistance protein (BCRP), multidrug resistance-associated protein 3 (MRP3) and P-glycoprotein (P-gp) using vesicular transport assays and determined the concentrations required for 50% inhibition (IC50 ). Then, we predicted the increase of statin exposure followed by the administration of PARP inhibitors using a mechanistic static model. Rucaparib was the strongest inhibitor of BCRP-mediated rosuvastatin transport (IC50 13.7 µM), followed by niraparib (42.6 µM) and olaparib (216 µM). PARP inhibitors did not affect MRP3. While niraparib appeared to inhibit P-gp, the inhibition showed large variability. The inhibition of intestinal BCRP by rucaparib, niraparib and olaparib was predicted to elevate rosuvastatin exposure by 52%, 37% and 24%, respectively. The interactions between PARP inhibitors and rosuvastatin are probably of minor clinical significance alone, but combined with other predisposing factors, they may increase the risk of rosuvastatin-associated adverse effects.

CYP2C19 loss-of-function alleles and use of omeprazole or esomeprazole increase the risk of cardiovascular outcomes in patients using clopidogrel.

Our aim was to investigate in a real-life prospective patient cohort how CYP2C19 loss-of-function (LOF) variants and CYP2C19 inhibitor omeprazole or esomeprazole influence the incidence of cardiovascular events in patients using clopidogrel. Data based simultaneously on these factors are conflicting and sparse. A cohort of prospective patients (n = 1972) with acute coronary syndrome (n = 1302) or symptomatic chronic coronary disease (n = 656) was followed for 365 days after hospitalization with information on purchased prescription drugs, hospital discharge, death, and genotype for CYP2C19*2, CYP2C19*3, and CYP2C19*8 LOF variants. The primary study outcome measurement was cardiovascular death or recurring myocardial infarction or stroke. Altogether, 608 patients (30.8%) carried CYP2C19 LOF alleles. During the 365-day follow-up 252 patients (12.8%) had an ischemic vascular event. Cardiovascular events were significantly more frequent in carriers of CYP2C19 LOF alleles (14.8%, 95% confidence interval [CI], 11.7-17.8) than in non-carriers (10.8%, 95% CI, 9.0-12.6, p = 0.0159). Omeprazole or esomeprazole use was similar among LOF allele carriers (n = 131, 21.5%) and non-carriers (n = 250, 18.3%, p = 0.185). Cardiovascular events were significantly more common in a composite group consisting of all CYP2C19 LOF carriers regardless of proton pump inhibitor use status and non-carriers using omeprazole or esomeprazole than in non-carriers not using omeprazole or esomeprazole (14.8%, 95% CI, 12.2-17.3 vs. 9.9%, 95% CI, 8.0-11.9, p = 0.00173). We observed significantly more cardiovascular events in carriers of CYP2C19 LOF variants and in non-carriers using omeprazole or esomeprazole. For optimal patient care, both genetics and concomitant medication should be considered.

The effect of hydroxychloroquine on cholesterol metabolism in statin treated patients after myocardial infarction.

Background and aims: To evaluate the effect of hydroxychloroquine (HCQ) on serum and lipoprotein lipids and serum biomarkers of cholesterol synthesis and absorption in myocardial infarction patients with a high-dose statin. Methods: Myocardial infarction patients (n = 59) with a constant statin dose were randomized to receive hydroxychloroquine 300 mg (n = 31) or placebo (n = 28) daily for six months and followed up for one year. Results: Statin reduced total-c (-26 ± 22% in hydroxychloroquine and -28 ± 19% in placebo group, P = 0.931), LDL-c (-38 ± 26% vs. -44 ± 23%, respectively, P = 0.299), and cholesterol synthesis biomarkers zymostenol, desmosterol, and lathosterol ratios from baseline to one year (e.g., serum lathosterol ratio -17 ± 45% vs. -15 ± 41%, respectively, P < 0.001 for both, P = 0.623 between groups). Compensatorily, cholesterol absorption increased during the intervention (e.g., serum campesterol ratio 125 ± 90% vs. 113 ± 72%, respectively, P < 0.001 for both, P = 0.488 between groups). Hydroxychloroquine did not affect cholesterol concentrations or cholesterol absorption. It prevented the statin-induced increase in cholesterol precursor, desmosterol ratio, from six months to one year in the hydroxychloroquine group (P = 0.007 at one year compared to placebo). Conclusions: Combined with a high-dose statin, hydroxychloroquine had no additional effect on serum cholesterol concentration or cholesterol absorption. However, the findings suggest that hydroxychloroquine interferes with lanosterol synthesis, and thereafter, it temporarily interferes with the cholesterol synthesis pathway, best seen in halting the increase of the desmosterol ratio.Trial Registration ClinicalTrials.gov Identifier: NCT02648464.

Real-world pharmacogenetics of statin intolerance: effects of SLCO1B1, ABCG2 , and CYP2C9 variants.

OBJECTIVE: The association of SLCO1B1 c.521T>C with simvastatin-induced muscle toxicity is well characterized. However, different statins are subject to metabolism and transport also by other proteins exhibiting clinically meaningful genetic variation. Our aim was to investigate associations of SLCO1B1 c.521T>C with intolerance to atorvastatin, fluvastatin, pravastatin, rosuvastatin, or simvastatin, those of ABCG2 c.421C>A with intolerance to atorvastatin, fluvastatin, or rosuvastatin, and that of CYP2C9*2 and *3 alleles with intolerance to fluvastatin. METHODS: We studied the associations of these variants with statin intolerance in 2042 patients initiating statin therapy by combining genetic data from samples from the Helsinki Biobank to clinical chemistry and statin purchase data. RESULTS: We confirmed the association of SLCO1B1 c.521C/C genotype with simvastatin intolerance both by using phenotype of switching initial statin to another as a marker of statin intolerance [hazard ratio (HR) 1.88, 95% confidence interval (CI) 1.08-3.25, P  = 0.025] and statin switching along with creatine kinase measurement (HR 5.44, 95% CI 1.49-19.9, P  = 0.011). No significant association was observed with atorvastatin and rosuvastatin. The sample sizes for fluvastatin and pravastatin were relatively small, but SLCO1B1 c.521T>C carriers had an increased risk of pravastatin intolerance defined by statin switching when compared to homozygous reference T/T genotype (HR 2.11, 95% CI 1.01-4.39, P  = 0.047). CONCLUSION: The current results can inform pharmacogenetic statin prescribing guidelines and show feasibility for the methodology to be used in larger future studies.

Characterization of Bile Acid Sulfate Conjugates as Substrates of Human Organic Anion Transporting Polypeptides.

Drug interactions involving the inhibition of hepatic organic anion transporting polypeptides (OATPs) 1B1 and OATP1B3 are considered important. Therefore, we sought to study various sulfated bile acids (BA-S) as potential clinical OATP1B1/3 biomarkers. It was determined that BA-S [e.g., glycochenodeoxycholic acid 3-O-sulfate (GCDCA-S) and glycodeoxycholic acid 3-O-sulfate (GDCA-S)] are substrates of OATP1B1, OATP1B3, and sodium-dependent taurocholic acid cotransporting polypeptide (NTCP) transfected into human embryonic kidney 293 cells, with minimal uptake evident for other solute carriers (SLCs) like OATP2B1, organic anion transporter 2, and organic cation transporter 1. It was also shown that BA-S uptake by plated human hepatocytes (PHH) was inhibited (≥96%) by a pan-SLC inhibitor (rifamycin SV), and there was greater inhibition (≥77% versus ≤12%) with rifampicin (OATP1B1/3-selective inhibitor) than a hepatitis B virus myristoylated-preS1 peptide (NTCP-selective inhibitor). Estrone 3-sulfate was also used as an OATP1B1-selective inhibitor. In this instance, greater inhibition was observed with GDCA-S (76%) than GCDCA-S (52%). The study was expanded to encompass the measurement of GCDCA-S and GDCA-S in plasma of SLCO1B1 genotyped subjects. The geometric mean GDCA-S concentration was 2.6-fold (90% confidence interval 1.6, 4.3; P = 2.1 × 10-4) and 1.3-fold (1.1, 1.7; P = 0.001) higher in individuals homozygous and heterozygous for the SLCO1B1 c.521T > C loss-of-function allele, respectively. For GCDCA-S, no significant difference was noted [1.2-fold (0.8, 1.7; P = 0.384) and 0.9-fold (0.8, 1.1; P = 0.190), respectively]. This supported the in vitro data indicating that GDCA-S is a more OATP1B1-selective substrate (versus GCDCA-S). It is concluded that GCDCA-S and GDCA-S are viable plasma-based OATP1B1/3 biomarkers, but they are both less OATP1B1-selective when compared to their corresponding 3-O-glucuronides (GCDCA-3G and GDCA-3G). Additional studies are needed to determine their utility versus more established biomarkers, such as coproporphyrin I, for assessing inhibitors with different OATP1B1 (versus OATP1B3) inhibition signatures.

The Sixth European Society of Pharmacogenomics and Personalised Therapy Congress.

On 8-9 November 2022, the European Society of Pharmacogenomics and Personalised Therapy organized its sixth biennial congress, in Belgrade, Serbia (congress website: www.sspt.rs). The congress aimed to address the current status and future perspectives of pharmacogenomics, share latest knowledge in the field of precision medicine and showcase the implementation of clinical applications in pharmacogenomics/pharmacogenetics. The 2 day congress consisted of 17 lectures given by key-opinion leaders and included a poster session plus discussions. The meeting was a great success by generating an informal environment and enabling the exchange of information between 162 participants from 16 different countries.

Toxicity and therapy outcome associations in LIG3, SLCO1B3, ABCB1, OPRM1 and GSTP1 in high-grade serous ovarian cancer.

Adverse effects are the major limiting factors in combinatorial chemotherapies. To identify genetic associations in ovarian cancer chemotherapy-induced toxicities and therapy outcomes, we examined a cohort of 101 patients receiving carboplatin-paclitaxel treatment with advanced high-grade serous ovarian cancers. Based on literature and database searches, we selected 19 candidate polymorphisms, designed a multiplex single nucleotide polymorphism-genotyping assay and applied Cox regression analysis, case-control association statistics and the log-rank Mantel-Cox test. In the Cox regression analysis, the SLCO1B3 rs1052536 AA-genotype was associated with a reduced risk of any severe toxicity (hazard ratio = 0.35, p = 0.023). In chi-square allelic test, the LIG3 rs1052536 T-allele was associated with an increased risk of neuropathy (odds ratio [OR] = 2.79, p = 0.031) and GSTP1 rs1695 G allele with a poorer response in the first-line chemotherapy (OR = 2.65, p = 0.026). In Kaplan-Meier survival analysis, ABCB1 rs2032582 TT-genotype was associated with shorter overall survival (uncorrected p = 0.025) and OPRM1 rs544093 GG and GT genotypes with shorter platinum-free interval (uncorrected p = 0.027) and progression-free survival (uncorrected p = 0.012). Results suggest that SLCO1B3 and LIG3 variants are associated with the risk of adverse effects in patients receiving carboplatin-paclitaxel treatment, the GSTP1 variant may affect the treatment response and ABCB1 and OPRM1 variants may influence the prognosis.

Rhabdomyolysis during concomitant ticagrelor and rosuvastatin: A breast cancer resistance protein-mediated drug interaction?

We present 3 patients diagnosed with rhabdomyolysis 1-6 months after the initiation of concomitant rosuvastatin and ticagrelor medication. A literature review and Food and Drug Administration adverse event reporting system revealed >40 reports of rhabdomyolysis during concomitant ticagrelor and rosuvastatin, including 3 with a fatal outcome. We show that ticagrelor inhibits breast cancer resistance protein-, organic anion transporting polypeptide (OATP) 1B1-, 1B3- and 2B1-mediated transport of rosuvastatin in vitro with half-maximal unbound inhibitory concentrations of 0.36, 4.13, 7.5 and 3.26 µM, respectively. A static drug interaction model predicted that ticagrelor may inhibit intestinal breast cancer resistance protein and thus increase rosuvastatin plasma exposure 2.1-fold, whereas the OATP-mediated hepatic uptake of rosuvastatin should not be inhibited due to relatively low portal ticagrelor concentrations. Taken together, concomitant use of ticagrelor with rosuvastatin may increase the systemic exposure to rosuvastatin and the risk of rosuvastatin-induced rhabdomyolysis. Further studies are warranted to investigate the potential pharmacokinetic interaction between ticagrelor and rosuvastatin in humans.

Functional Characterization of Six SLCO1B1 (OATP1B1) Variants Observed in Finnish Individuals with a Psychotic Disorder.

Variants in the SLCO1B1 (solute carrier organic anion transporter family member 1B1) gene encoding the OATP1B1 (organic anion transporting polypeptide 1B1) protein are associated with altered transporter function that can predispose patients to adverse drug effects with statin treatment. We explored the effect of six rare SLCO1B1 single nucleotide variants (SNVs) occurring in Finnish individuals with a psychotic disorder on expression and functionality of the OATP1B1 protein. The SUPER-Finland study has performed exome sequencing on 9381 individuals with at least one psychotic episode during their lifetime. SLCO1B1 SNVs were annotated with PHRED-scaled combined annotation-dependent (CADD) scores and the Ensembl variant effect predictor. In vitro functionality studies were conducted for the SNVs with a PHRED-scaled CADD score of >10 and predicted to be missense. To estimate possible changes in transport activity caused by the variants, transport of 2',7'-dichlorofluorescein (DCF) in OATP1B1-expressing HEK293 cells was measured. According to the findings, additional tests with rosuvastatin and estrone sulfate were conducted. The amount of OATP1B1 in crude membrane fractions was quantified using a liquid chromatography tandem mass spectrometry-based quantitative targeted absolute proteomics analysis. Six rare missense variants of SLCO1B1 were identified in the study population, located in transmembrane helix 3: c.317T>C (p.106I>T), intracellular loop 2: c.629G>T (p.210G>V), c.633A>G (p.211I>M), c.639T>A (p.213N>L), transmembrane helix 6: 820A>G (p.274I>V), and the C-terminal end: 2005A>C (p.669N>H). Of these variants, SLCO1B1 c.629G>T (p.210G>V) resulted in the loss of in vitro function, abolishing the uptake of DCF, estrone sulfate, and rosuvastatin and reducing the membrane protein expression to 31% of reference OATP1B1. Of the six rare missense variants, SLCO1B1 c.629G>T (p.210G>V) causes a loss of function of OATP1B1 transport in vitro and severely decreases membrane protein abundance. Carriers of SLCO1B1 c.629G>T might be susceptible to altered pharmacokinetics of OATP1B1 substrate drugs and might have increased likelihood of adverse drug effects such as statin-associated musculoskeletal symptoms.

Extraesophageal reflux and reflux aspiration in dogs with respiratory diseases and in healthy dogs.

BACKGROUND: Salivary bile acids are used to diagnose extraesophageal reflux (EER) and to evaluate the risk of reflux aspiration that is associated with respiratory diseases in dogs. OBJECTIVES: To study total bile acid (TBA) concentrations in saliva and in bronchoalveolar lavage fluid (BALF) to investigate EER and reflux aspiration in dogs with respiratory diseases and in healthy dogs. ANIMALS:  Thirty-one West Highland White Terriers (WHWTs) with idiopathic pulmonary fibrosis (IPF), 12 dogs with inflammatory airway disease (IAD), 6 dogs with recurrent pneumonia (RP), 26 brachycephalic dogs (BD), 27 healthy WHWTs (HW), 52 healthy dogs (HD). All privately-owned dogs. METHODS: Saliva and BALF were collected from dogs in each group. RESULTS: Salivary TBA concentrations were higher in IPF (median 0.1692 µM, interquartile range [IQR] 0.1115-0.2925 µM, Cohen's d 3.4, 95% confidence interval [CI] 2.2-4.0, P < .001) and BD (0.0256 µM, IQR 0.0086-0.0417 µM, d 0.5, CI -0.1 to 1.1, P = .003) compared to HD (0 µM, IQR not quantifiable [n.q.]-0.0131 µM). Bronchoalveolar lavage fluid TBA concentrations were higher in IPF (0.0117 µM, IQR 0.0048-0.0361 µM, d 0.5, CI 0-1.1, P < .001) compared to HD (0 µM, IQR n.q.-0.0074 µM). CONCLUSION AND CLINICAL IMPORTANCE: Extraesophageal reflux and reflux aspiration occur in healthy dogs and those with respiratory diseases.