Effects of sevelamer carbonate versus calcium acetate on vascular calcification,inflammation, and endothelial dysfunction in chronic kidney disease

Hyperphosphatemia is present in most patients with end‐stage renal disease (ESRD) and has been associated with increased cardiovascular mortality. Phosphate binders (calcium‐based and calcium free) are the mainstay pharmacologic treatment to lower phosphorus levels in patients with ESRD. We evaluated biochemical markers of vascular calcification, inflammation, and endothelial dysfunction in patients with chronic kidney disease (CKD) treated with sevelamer carbonate (SC) versus calcium acetate (CA). Fifty patients with CKD (stages 3 and 4) were enrolled and assigned to treatment with SC and CA for 12 weeks. At the end of the study the biomarkers of vascular calcification, inflammation, and endothelial dysfunction were analyzed. A significant increase in HDL‐cholesterol was observed with SC but not with CA in patients with CKD. Treatment with SC reduced serum phosphate, calcium phosphate, and FGF‐23 levels and there was no change with CA treatment. The inflammatory markers IL‐8, IFN‐γ, and TNFα decreased with response to both treatments. The levels of IL‐6 significantly increased with CA treatment and no change was observed in the SC treatment group. SC showed favorable effects on anti‐inflammatory and vascular calcification biomarkers compared to CA treatment in patients with CKD stages 3 and 4 with normal phosphorous values.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Non‐calcium‐based phosphate binders are effective in the patients with end stage kidney disease for lowering serum phosphorus and have demonstrated anti‐inflammatory effects.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This study demonstrates a favorable reduction in systemic, vascular, and bone‐related inflammatory markers from treatment with sevelamer carbonate (SC) in the patients with chronic kidney disease (CKD) not on dialysis with normal serum phosphorus levels.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

This study suggests that patients with CKD not on dialysis may benefit from SC phosphate binders despite having a normal serum phosphorus level.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

This study offers insight to the role phosphates binder may play in lowering inflammation and vascular calcification in patients with CKD not on dialysis.     

Non‐synonymous alterations in AKR7A3 and ABCA6 correlate with bleeding in aged patients treated with rivaroxaban

Rivaroxaban is an oral anticoagulant that inhibits thrombin and blocks coagulation cascade through directly inactivating factors Xa. Despite rivaroxaban is widely used for prevention and treatment of venous thrombosis, and its common adverse reactions have been reported, including abnormal coagulation, mucosal hemorrhage, hematuria, and intracranial hemorrhage. To explore potential drivers of individual differences in adverse reactions induced by rivaroxaban, we performed whole‐exome sequencing and found that AKR7A3 rs1738023/rs1738025 and ABCA6 rs7212506 are susceptible sites for rivaroxaban‐related bleeding in aged patients treated with rivaroxaban. Gene functional annotation and signaling pathway enrichment indicated that homozygous mutations in AKR7A3 and ABCA6 might alter normal rivaroxaban transport and metabolism, and lead to continuous accumulation of activated drugs and toxic substances in vivo. Our results suggested that interindividual differences in bleeding events induced by rivaroxaban may be potentially driven by genetic alterations related to abnormal metabolism and transport of rivaroxaban.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Although rivaroxaban has been wildly used for the prevention and treatment of prevent of deep vein thrombosis without requiring routine coagulation monitoring, the adverse events, such as bleeding following rivaroxaban treatment, has not been fully addressed.

• WHAT QUESTION DID THIS STUDY ADDRESS?

The correlation between genetic variations and rivaroxaban treatment‐induced side effects (e.g., bleeding).

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

The AKR7A3 rs1738023/rs1738025 and ABCA6 rs7212506 confer susceptibility to adverse reactions caused by rivaroxaban.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY AND TRANSLATIONAL SCIENCE?

This study identified AKR7A3 and ABCA6 genes involved in drug metabolism and transport associated with susceptibility to rivaroxaban‐related bleeding events, and provided supporting evidence for the prevention and treatment of anticoagulant‐caused adverse effects.     

Safety,tolerability, pharmacokinetics,and pharmacodynamics of a TLR7 agonist prodrug RO6870868 in healthy volunteers

RO6870868 is an oral prodrug of the toll‐like receptor 7 (TLR7) specific agonist, RO6871765. TLR7 agonists augment host immune activity and are in development to treat hepatitis B infection. We evaluated the safety, tolerability, pharmacokinetics (PKs), and pharmacodynamics (PDs) of RO6870868 in a first‐in‐human, phase I, randomized, single ascending oral dose study in 60 healthy volunteers at 6 dose levels (200–2000 mg). Single oral doses were generally well‐tolerated with a predictable safety profile associated with dose‐dependent increases in systemic interferon. No serious adverse events (AEs) were reported and no subject withdrew from the study due to an AE. No clinically significant changes were observed in vital signs, electrocardiograms, or laboratory parameters. Following oral RO6870868 doses, plasma RO6871765 concentrations increased rapidly, exhibiting mean terminal half‐life ranging 2–6 h across all cohorts, with area under the plasma concentration versus time curve extrapolated to infinity (AUC_0‐∞) increasing proportionally with dose. A pattern of dose and time‐dependent PD activity was demonstrated consistent with engagement of the TLR7 system. Single RO6870868 doses activated components of the TLR innate immune system in a dose‐dependent manner with adequate safety and tolerability. Single‐dose data in healthy volunteers are useful to evaluate safety, PK, and PD activity of TLR7 agonists and help to guide dose and regimen selection for further trials in patients with chronic hepatitis B.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Toll‐like receptor 7 (TLR7) agonists induce broad immune‐enhancing effects and may play a role in overcoming the adaptive and innate immune defects in chronic hepatitis B infection.

• WHAT QUESTION DID THIS STUDY ADDRESS?

The safety, tolerability, pharmacokinetics, and pharmacodynamics of single oral doses of RO6870868 (a prodrug of the specific TLR7 agonist RO6871765) in healthy volunteers.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

RO6870868 was safe and acceptably tolerated across the dose range in healthy volunteers. Oral administration results in the rapid appearance of the active TLR7 agonist RO6871765 and leads to a profile of gene expression typical for TLR7 agonism, including activation of interferon and interferon‐response genes. Gene activation occurs at RO6871765 exposure associated with single RO6870868 doses greater than or equal to 800 mg, with a plateau for several markers at doses between 1200 mg and 1600 mg.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

The study results help to guide dose and regimen selection for clinical trials with RO6870868 and other potent TLR7 activators.     

Pharmacokinetics and tolerability of apremilast in healthy Korean adult men

We performed a two‐part study to evaluate the pharmacokinetics, safety, and tolerability of oral apremilast, a phosphodiesterase 4 inhibitor indicated for the treatment of psoriasis, in healthy Korean adult men. In part 1, there were 12 subjects who randomly received a single oral dose of apremilast at 20, 30, or 40 mg in each of 3 periods in a crossover fashion. In part 2, there were 16 subjects who randomly received 30 mg of apremilast or its matching placebo in a ratio of 3:1 twice daily for 14 days. Apremilast was rapidly absorbed (maximum concentration: ~2–3 h postdose), and eliminated according to a monoexponential pattern with a terminal‐phase elimination half‐life of 8–9 h. The exposure to apremilast increased in a dose‐proportional manner and accumulation was 1.6‐fold at steady‐state. Apremilast was well‐tolerated after a single oral administration and multiple oral administrations in Korean adult men; all of the treatment‐emergent adverse events were mild and recovered without sequelae. In conclusion, apremilast was safe and well‐tolerated in healthy Korean adult men when administered single oral doses of 20, 30, or 40 mg or when administered multiple oral doses of 30 mg b.i.d. for 14 days. Overall exposures increased in an approximate dose proportional manner in healthy Korean adult men.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Apremilast, a phosphodiesterase 4 inhibitor, has been approved to treat patients with psoriasis in many countries, including the United States, Canada, and Japan. Although apremilast has shown a linear pharmacokinetic (PK) profile and little ethnic sensitivity, apremilast has never been studied specifically in Koreans.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This two‐part study evaluated differences in PKs and tolerability of apremilast between healthy Korean adult men and previously studied ethnic populations.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Our results clearly showed that apremilast was safe and well‐tolerated after single and multiple oral administrations in healthy Korean adult men. Linear PK profiles of apremilast were consistently observed in healthy Korean adult men.

• HOW MIGHT THIS CHANGE DRUG DISCOVERY, DEVELOPMENT, AND/OR THERAPEUTICS?

Our results support the notion that recommended apremilast dose of 30 mg b.i.d., after a first week of titration, would be also appropriate in Koreans.     

Safety,tolerability, and pharmacokinetics of single‐ and multiple‐dose administration of islatravir (MK‐8591) in adults without HIV

Islatravir (MK‐8591) is a nucleoside analogue in development for the treatment and prevention of HIV‐1. Two phase 1 trials were conducted during initial evaluation of islatravir: rising single doses (Study 1) and rising multiple doses (Study 2) of oral islatravir in male and female participants without HIV (aged 18–60 years). Safety, tolerability, and pharmacokinetics of islatravir (plasma) and islatravir‐triphosphate (peripheral blood mononuclear cells) were assessed. In Study 1, 24 participants, assigned to 1 of 3 panels, received alternating single doses of islatravir in a fasted state from 5 mg to 400 mg, or placebo, over 3 dosing periods; a 30 mg dose was additionally assessed following a high‐fat meal. In Study 2, 8 participants per dose received 3 once‐weekly doses of 10, 30, or 100 mg islatravir or placebo in a fasted state. For each panel in both trials, 6 participants received active drug and 2 received placebo. Islatravir was generally well‐tolerated, with no serious adverse events or discontinuations due to adverse events. Islatravir was rapidly absorbed (median time to maximum plasma concentration 0.5 hours); plasma half‐life was 49–61 h; intracellular islatravir‐triphosphate half‐life was 118–171 h. Plasma exposure increased in an approximately dose‐proportional manner; there was no meaningful food effect. There was a modest degree of intracellular islatravir‐triphosphate accumulation after multiple weekly dosing. After single oral doses of islatravir greater than or equal to 5 mg, intracellular islatravir‐triphosphate levels were comparable to levels associated with efficacy in preclinical studies. These results warrant continued clinical investigation of islatravir.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

​Current HIV treatment and prevention strategies have limitations, and novel agents that offer improved safety and tolerability, a high barrier to HIV resistance, and more convenient dosing regimens are required.

• WHAT QUESTION DID THIS STUDY ADDRESS?

Two phase 1 studies in participants without HIV assessed safety and pharmacokinetics of rising single and multiple doses of oral islatravir, a nucleoside analogue, to support continued development for the treatment and prevention of HIV‐1 infection.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Islatravir was generally well‐tolerated at single doses up to 400 mg. Oral doses of islatravir greater than or equal to 10 mg resulted in intracellular peripheral blood mononuclear cell levels of the active form, islatravir‐triphosphate, comparable to those associated with antiviral efficacy in preclinical studies.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

These studies provide important safety and pharmacokinetic information about islatravir in adults without HIV, which will be used to support further clinical investigation of islatravir for the treatment and prevention of HIV‐1 infection.     

Propsective evaluation of high‐dose methotrexate pharmacokinetics in adult patients with lymphoma using novel determinants of kidney function

High‐dose methotrexate (HDMTX) pharmacokinetics (PKs), including the best estimated glomerular filtration rate (eGFR) equation that reflects methotrexate (MTX) clearance, requires investigation. This prospective, observational, single‐center study evaluated adult patients with lymphoma treated with HDMTX. Samples were collected at predefined time points up to 96 h postinfusion. MTX and 7‐hydroxy‐MTX PKs were estimated by standard noncompartmental analysis. Linear regression determined which serum creatinine‐ or cystatin C‐based eGFR equation best predicted MTX clearance. The 80 included patients had a median (interquartile range [IQR]) age of 68.6 years (IQR 59.2–75.6), 54 (67.5%) were men, and 74 (92.5%) were White. The median (IQR) dose of MTX was 7.6 (IQR 4.8–11.3) grams. Median clearance was similar across three dosing levels at 4.5–5.6 L/h and was consistent with linear PKs. Liver function, weight, age, sex, concomitant chemotherapy, and number of previous MTX doses did not impact clearance. MTX area under the curve (AUC) values varied over a fourfold range and appeared to increase in proportion to the dose. The eGFR_cys (ml/min) equation most closely correlated with MTX clearance in both the entire cohort and after excluding outlier MTX clearance values (r = 0.31 and 0.51, respectively). HDMTX as a 4‐h infusion displays high interpatient pharmacokinetic variability. Population PK modeling to optimize MTX AUC attainment requires further evaluation. The cystatin C‐based eGFR equation most closely estimated MTX clearance and should be investigated for dosing and monitoring in adults requiring MTX as part of lymphoma management.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Methotrexate (MTX) clearance has a relationship with glomerular filtration rate (GFR), which is often calculated using serum creatinine as a surrogate marker of renal clearance; however, kidney function estimation derived from serum creatinine‐based GFR formulas has several known limitations, particularly in patients with cancer.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This study attempts to answer the question of which estimated GFR (eGFR) equation has the strongest correlation with MTX clearance.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Results of this study suggest that, when high‐dose MTX is administered, cystatin C based eGFR equations more strongly correlate with MTX clearance than eGFR equations based on serum creatinine alone.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Incorporating cystatin C into baseline evaluation when estimating kidney function has potential to improve MTX safety and optimize MTX exposure.     

Imeglimin population pharmacokinetics and dose adjustment predictions for renal impairment in Japanese and Western patients with type 2 diabetes

Imeglimin is an orally administered first‐in‐class drug to treat type 2 diabetes mellitus (T2DM) and is mainly excreted unchanged by the kidneys. The present study aimed to define the pharmacokinetic (PK) characteristics of imeglimin using population PK analysis and to determine the optimal dosing regimen for Japanese patients with T2DM and chronic kidney disease (CKD). Imeglimin plasma concentrations in Japanese and Western healthy volunteers, and patients with T2DM, including patients with mild to severe CKD with an estimated glomerular filtration rate (eGFR) greater than 14 ml/min/1.73 m² were included in a population PK analysis. PK simulations were conducted using a population PK model, and the area under concentration‐time curve (AUC) was extrapolated with power regression analysis to lower eGFR. The influence of eGFR, weight, and age on apparent clearance and of dose on relative bioavailability were quantified by population PK analysis. Simulations and extrapolation revealed that the recommended dosing regimen based on the AUC was 500 mg twice daily (b.i.d.) for patients with eGFR 15–45 ml/min/1.73 m², and 500 mg with a longer dosing interval was suggested for those with eGFR less than 15. Simulations revealed that differences in plasma AUCs between Japanese and Western patients at the same dose were mainly driven by a difference in the eGFR and that the plasma AUC after 1000 and 1500 mg b.i.d. in Japanese and Western patients, respectively, was comparable in the phase IIb studies. These results indicate suitable dosages of imeglimin in the clinical setting of T2DM with renal impairment.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Imeglimin is a first‐in‐class oral agent for the treatment of type 2 diabetes (T2DM) and is excreted unchanged into urine. A Japanese phase IIb study found that 1000 mg b.i.d. was optimal in Japanese population, and phase III studies confirmed significant glucose lowering effect. A Western phase IIb study found an optimal dose of 1500 mg b.i.d.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This study addressed the key determinants of imeglimin pharmacokinetics (PKs), recommended doses for patients with renal impairment, and what drives the different optimal doses between Japanese and Western patients with T2DM.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Renal function significantly impacts imeglimin PKs. Recommended doses for patients with renal impairment have been proposed for exposure matching. Differences in estimated glomerular filtration rate (eGFR) comprised the key driver for different optimal doses at which estimated exposures were similar between Japanese and Western patients.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Doses of imeglimin could be reduced based on eGFR. Exposure responses seemed similar between Japanese and Western patients.     

Limited sampling strategies for estimation of tacrolimus exposure in kidney transplant recipients receiving extended‐release tacrolimus preparation

Tacrolimus is the key component of most contemporary immunosuppressive drug regimens for the prevention of transplant rejection. Area under the concentration time curve over 24 h (AUC_0–24) predicts efficacy, but predose (trough) tacrolimus blood concentration (C₀) is currently used to guide dosing. In clinical or research situations where an estimate of AUC is required, collection of a full 24 h pharmacokinetic (PK) profile is cumbersome. Limited sampling strategies (LSSs) have been developed for some tacrolimus preparations but not for the new, extended‐release, once‐daily formulation of tacrolimus, ENVARSUS XR. Twenty‐four kidney transplant recipients were enrolled in this study. Twenty‐four tacrolimus PK profiles were obtained over 24 h. Multiple linear regression was used to generate LSSs with the best subset selection for accurate estimation of tacrolimus AUC_0–24. The predictive performance of each model was assessed in the evaluation group. The correlation between actual and predicted AUC_0–24 was evaluated and mean percentage prediction error (MPE%), mean absolute percentage prediction error (MAE%), and root mean squared error (RMSE) were calculated for each prediction model to assess bias and precision. The selected LSSs were highly correlated to AUC_0–24 compared with the correlation between C₀ and AUC_0‐24. Two and three sampling points limited sampling strategies: C₀, C₂, and C₁₀ provide the most reliable and effective LSS for estimation of tacrolimus AUC_0–24 in routine clinic use. These limited sampling models can be applied in therapeutic drug monitoring schemes to personalize tacrolimus dosing for kidney transplant recipients on treatment with extended‐release tacrolimus.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Tacrolimus is a narrow therapeutic index drug with wide pharmacokinetic (PK) variability between individuals. There is evidence that tacrolimus exposure based on blood concentration (C₀) monitoring can vary extensively. Although AUC is considered the best exposure indicator related to tacrolimus clinical effects, tacrolimus C₀ monitoring is the most commonly used method in routine clinical practice. There is no limited sampling strategy (LSS) available for kidney transplant recipients using extended‐released tacrolimus.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This study assessed different LSSs for an accurate estimation of area under the concentration time curve over 24 h (AUC_0–24) for extended‐released tacrolimus.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Tacrolimus exposure can be accurately measured using two and three sampling points of LSS in kidney transplant recipients using extended‐released tacrolimus.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

These LSSs can be applied in therapeutic drug monitoring (TDM) schemes to personalize tacrolimus dosing in routine clinical practice for kidney transplant recipients receiving extended‐released tacrolimus. Moreover, it can be used in PK clinical trials providing an accurate AUC_0–24 estimation. It also can have useful implementation in the new micro‐sampling techniques.     

A randomized crossover study comparing different tacrolimus formulations to reduce intrapatient variability in tacrolimus exposure in kidney transplant recipients

A high intrapatient variability (IPV) in tacrolimus exposure is a risk factor for poor long‐term outcomes after kidney transplantation. The main objective of this trial was to investigate whether tacrolimus IPV decreases after switching patients from immediate‐release (IR)‐tacrolimus to either extended‐release (ER)‐tacrolimus or LifeCyclePharma (LCP)‐tacrolimus. In this randomized, prospective, open‐label, cross‐over trial, adult kidney transplant recipients on a stable immunosuppressive regimen, including IR‐tacrolimus, were randomized for conversion to ER‐tacrolimus or LCP‐tacrolimus, and for the order in which IR‐tacrolimus and the once‐daily formulations were taken. Patients were followed 6 months for each formulation, with monthly tacrolimus predose concentration assessments to calculate the IPV. The IPV was defined as the coefficient of variation (%) of dose corrected predose concentrations. Ninety‐two patients were included for analysis of the primary outcome. No significant differences between the IPV of IR‐tacrolimus (16.6%) and the combined once‐daily formulations (18.3%) were observed (% difference +1.7%, 95% confidence interval [CI] −1.1% to ‒4.5%, p = 0.24). The IPV of LCP‐tacrolimus (20.1%) was not significantly different from the IPV of ER‐tacrolimus (16.5%, % difference +3.6%, 95% CI −0.1% to 7.3%, p = 0.06). In conclusion, the IPV did not decrease after switching from IR‐tacrolimus to either ER‐tacrolimus or LCP‐tacrolimus. These results provide no arguments to switch kidney transplant recipients from twice‐daily (IR) tacrolimus formulations to once‐daily (modified‐release) tacrolimus formulations when the aim is to lower the IPV.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

High intrapatient variability (IPV) in tacrolimus exposure is associated with poor kidney transplant outcomes. Different causes of a high IPV are considered, like drug‐drug interactions, food intake, and adherence and the type of tacrolimus formulation.

• WHAT QUESTION DID THIS STUDY ADDRESS?

Does switching from a twice‐daily immediate‐release (IR) formulation to a once‐daily modified‐release tacrolimus formulation with a flatter pharmacokinetic (PK) profile lower the IPV of tacrolimus in stable kidney transplant recipients?

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

We could not demonstrate a decrease in tacrolimus IPV after switching from IR‐ to modified‐release tacrolimus formulations in stable kidney transplant recipients. Tremor, an important side effect of tacrolimus, seems to occur less frequently with LifeCyclePharma‐tacrolimus compared to IR‐tacrolimus.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Tacrolimus IPV seems not to be influenced by different PK profiles of the different tacrolimus formulations.     

Evaluation of the potential for pharmacokinetic interaction between tirabrutinib and levonorgestrel/ethinyl estradiol in healthy female volunteers

Tirabrutinib (TIRA), a potent and nonreversible oral Bruton tyrosine kinase inhibitor, is evaluated for treatment of certain hematological malignancies and inflammatory diseases. A drug–drug interaction study to evaluate the effect of TIRA on the pharmacokinetics of the oral contraceptive levonorgestrel (LEVO)/ethinyl estradiol (EE) was conducted in healthy female participants (N = 26). Participants received a single dose of LEVO (150 mcg)/EE (30 mcg) alone (reference), and on day 12 of a 15‐day regimen of TIRA 160 mg once‐daily (test). Intensive blood sampling for determination of LEVO, EE, and TIRA plasma concentrations was conducted, and safety was assessed throughout the study. Pharmacokinetic interactions were evaluated using 90% confidence intervals (CIs) of the geometric least squares mean (GLSM) ratios of the test versus reference treatments. The GLSM (90% CI) ratios of area under the concentration‐time curve from zero to infinity (AUC_inf; LEVO: 0.95, 95% CI: 0.88–1.03, EE: 1.10, 95% CI: 1.05–1.16) and maximum plasma concentration (C_max; LEVO: 0.85, 95% CI: 0.74–0.98, EE: 1.07, 95% CI: 0.98–1.18) were within the prespecified 0.70 to 1.43 no effect bounds; and the AUC ratios met the stricter 0.80 to 1.25 equivalence bounds. Study treatments were generally well‐tolerated. In conclusion, co‐administration with TIRA did not alter the exposure of LEVO/EE, and accordingly LEVO/EE containing oral contraceptives can serve as a contraception method for participants on TIRA 160 mg (or lower) daily doses.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Tirabrutinib (TIRA) is a Bruton tyrosine kinase inhibitor developed for treatment of certain hematological malignancies and inflammatory diseases. Due to teratogenic potential of TIRA, enrollment of women of childbearing age is contingent upon the use of highly effective contraception.

• WHAT QUESTION DID THIS STUDY ADDRESS?

The study evaluated the potential effect of TIRA 160 mg once‐daily regimen on the exposure of a hormonal oral contraceptive containing levonorgestrel (LEVO) and ethinyl estradiol (EE).

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

TIRA 160 mg once daily did not have any clinically relevant impact on the exposures of LEVO and EE.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Combination oral contraception containing LEVO and EE can be allowed as a highly effective form of contraception during administration of TIRA at 160 mg once daily or lower daily doses.     

Pharmacokinetics and pharmacodynamics of itepekimab in healthy adults and patients with asthma: Phase I first‐in‐human and first‐in‐patient trials

Itepekimab is a monoclonal antibody that targets interleukin (IL‐33) and has been shown to reduce airway inflammation and associated tissue damage in preclinical studies. We assessed the safety, tolerability, pharmacokinetics (PKs), and pharmacodynamic profiles of single‐ascending and multiple‐ascending doses of itepekimab in two randomized, double‐blind, placebo‐controlled phase I studies. Healthy adults (N = 40) were randomized to the single‐dose study and patients with moderate asthma (N = 23) to the multiple‐dose study. Itepekimab was administered intravenously (0.3, 1, 3, or 10 mg/kg infusion) or subcutaneously (150 mg) in the single‐dose study and subcutaneously (75 or 150 mg weekly for 4 weeks) in the multiple‐dose study. Itepekimab exhibited linear PKs across studies and dose‐proportional increases in mean maximum concentration in serum and area under the concentration–time curve following single intravenous or multiple subcutaneous doses. Itepekimab demonstrated mean subcutaneous bioavailability of 59–73% and a long terminal half‐life (30.0–31.6 days). IL‐33 concentrations in most healthy participants and patients with asthma were undetectable at baseline. Following administration of itepekimab in both studies, total IL‐33 concentrations increased and blood eosinophils decreased, both with durable effect. Itepekimab was well‐tolerated in both studies with no detection of treatment‐emergent anti‐drug antibody responses.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Preclinical data suggest that itepekimab, a monoclonal antibody targeting IL‐33, may benefit patients with chronic inflammatory airway diseases by blocking IL‐33–mediated pathologic inflammation. Neither the pharmacokinetic (PK) profile of itepekimab nor its safety has been fully elucidated in first‐in‐human or first‐in‐patient studies.

• WHAT QUESTION DID THIS STUDY ADDRESS?

The study evaluated the initial safety of itepekimab, and its PK and pharmacodynamic activity in healthy adults and patients with asthma.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Itepekimab demonstrated linear and dose‐proportional PKs in our studies and was well‐tolerated, with no evidence of immunogenicity. These findings have facilitated dose and regimen selection for subsequent clinical studies in patients with asthma and chronic obstructive pulmonary disease.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Itepekimab is one of a few anti‐alarmin biologics under development; if successful, it may provide an alternative mechanism of action with which to target chronic inflammatory airway diseases, alone or in combination with other targeted therapies.     

Effects of elagolix on the pharmacokinetics of omeprazole and its metabolites in healthy premenopausal women

This study evaluated the effect of repeated doses of elagolix on the pharmacokinetics (PK) of omeprazole and its metabolites in healthy premenopausal female subjects. Adult premenopausal female subjects (N = 20) received a single oral dose of omeprazole (40 mg) on day 1 and day 11 and oral doses of elagolix (300 mg) twice‐daily on days 3–11. Serial blood samples for assay of omeprazole and its metabolites were collected for 24 h after dosing on days 1 and 11. PK parameters were calculated for omeprazole, 5‐hydroxyomeprazole and omeprazole sulfone; and were compared between day 1 and day 11. Pharmacogenetic testing was performed for CYP2C19 variant alleles and the results were used to compare the magnitude of elagolix–omeprazole drug–drug interaction (DDI) between the different genotype subgroups. Administration of elagolix 300 mg twice‐daily for 9 days increased omeprazole exposure by 1.8‐fold and decreased the metabolite‐to‐parent ratio for 5‐hydroxyomeprazole by ~60%. Conversely, there was an increase in the metabolite‐to‐parent ratio for omeprazole sulfone by 25%. Elagolix increased omeprazole exposures by 2‐ to 2.5‐fold in CYP2C19 extensive (EM) and intermediate (IM) metabolizer subjects, but decreased omeprazole exposures by 40% in poor metabolizer subjects. Exposures of 5‐hydroxyomeprazole decreased by 20%–30% in all genotype subgroups, and omeprazole sulfone exposures increased by ~3‐fold in EM and IM subjects. Elagolix is a weak inhibitor of CYP2C19 and exposure of CYP2C19 substrates may be increased upon coadministration with elagolix. Omeprazole may exhibit drug interactions due to multiple mechanisms other than CYP2C19‐mediated metabolism; complicating the interpretation of results from omeprazole DDI studies.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Elagolix is an inhibitor of P‐glycoprotein (P‐gp) and a weak‐to‐moderate inducer of cytochrome P450 3A (CYP3A4). In vitro, elagolix was identified as a possible inhibitor of CYP2C19 with potential to increase plasma concentrations of drugs that are substrates of CYP2C19 if they are coadministered with elagolix.

• WHAT QUESTION DID THIS STUDY ADDRESS?

What are the effects of elagolix on the pharmacokinetics of omeprazole and its metabolites in healthy subjects with different CYP2C19 genotypes and are P‐gp and/or CYP3A4 potentially involved in the interaction between elagolix and omeprazole?

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

This study suggests that elagolix is a weak inhibitor of CYP2C19 and exposure of other CYP2C19 substrates may be increased upon coadministration with elagolix. These results also suggest P‐gp, CYP3A4, and/or another unknown mechanism may also be potential mechanisms for drug interactions with omeprazole.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Future DDI studies with omeprazole as a CYP2C19 substrate should consider that omeprazole may exhibit complex drug interactions due to multiple mechanisms mediating metabolism and transport, which may confound the interpretation of study results.     

Tissue pharmacokinetics of DHP107, a novel lipid‐based oral formulation of paclitaxel,in mice and patients by positron emission tomography

DHP107 is a newly developed lipid‐based oral formulation of paclitaxel. We evaluated the in vivo tissue pharmacokinetics (PKs) of DHP107 in mice and patients using positron emission tomography (PET). Radioisotope‐labeled [³H]DHP107 and [¹⁸F]DHP107 for oral administration were formulated in the same manner as the manufacturing process of DHP107. In vivo tissue PK were assessed in healthy ICR mice and breast cancer xenografted SCID mice. Two patients with metastatic breast cancer were clinically evaluated for absorption at the target lesion after internal absorbed dose estimation. Whole‐body PET/computed tomography data were acquired in healthy and xenografted mice and in patients up to 10–24 h after administration. Tissue [¹⁸F]DHP107 signals were plotted against time and PK parameters were determined. The amounts of radioactivity in various organs and excreta were determined using a beta‐counter and are expressed as the percentage of injected dose (ID). Oral [¹⁸F]DHP107 was well‐absorbed and reached the target lesion in mice and patients with breast cancer. Significant amounts of radioactivity were found in the stomach, intestine, and liver after oral administration of [³H]‐ and [¹⁸F]DHP107 in healthy mice. The [¹⁸F]DHP107 reached a peak distribution of 0.7–0.8%ID in the tumor at 5.6–7.3 h in the xenograft model. The [¹⁸F]DHP107 distribution in patients with metastatic breast cancer was the highest at 3–4 h postadministration. Systemic exposures after administration of a DHP107 therapeutic dose were comparable with those in previous studies. PET using radioisotope‐labeled drug candidates is useful for drug development and can provide valuable information that can complement plasma PK data, particularly in early phase clinical trials.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

PET allows visualizing and quantifying the tissue pharmacokinetic properties of a drug throughout the body.

• WHAT QUESTION DID THIS STUDY ADDRESS?

What is the tissue pharmacokinetic profile of DHP107, a novel oral paclitaxel, when administered with [¹⁸F]DHP107 to mice and humans with breast cancer?

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

PET/CT studies enabled for evaluating the relative amount and its time profile of orally administered [¹⁸F]DHP107, distributed to each organ and tissue, in mice and patients with breast cancer. In a clinical trial with two metastatic breast cancer patients, oral [¹⁸F]DHP107 was well absorbed and its localization in the tumor lesion was successfully visualized.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

PET/CT imaging using radioisotope‐labeled drug candidates can provide information on drug properties by exploring the tissue pharmacokinetics in early drug development.     

Pharmacokinetics and safety of a novel influenza treatment (baloxavir marboxil) in Korean subjects compared with Japanese subjects

Baloxavir marboxil, a novel influenza therapeutic agent, is a prodrug rapidly metabolized into its active form, baloxavir acid, which inhibits cap‐dependent endonuclease. This study evaluated the pharmacokinetics (PKs) and safety of baloxavir acid in healthy Korean subjects and compared them with published data in Japanese subjects. This open‐label and single‐ascending dose study was conducted in 30 Korean male subjects, with a single oral dose of baloxavir marboxil (20, 40, or 80 mg) administered to eight subjects each; additionally, 80 mg was administered to six subjects (body weight >80 kg). Noncompartmental and population PK analyses were performed, and results were compared with those of Japanese subjects. Appropriateness of the body weight‐based dosing regimen was evaluated by simulation. PK profiles of baloxavir acid revealed multicompartment behavior with a long half‐life (80.8–98.3 h), demonstrating a dose‐proportional increase. Baloxavir acid reached peak plasma concentration from 3.5 to 4.0 h postdosing. Body weight was identified as a significant covariate of apparent oral clearance and apparent volume of distribution, which was similar to that observed in Japanese subjects. Body weight‐adjusted analysis revealed that exposure to baloxavir acid did not significantly differ between Korean and Japanese subjects. Simulated exposures to baloxavir acid demonstrated that the body weight‐based dosing regimen for baloxavir marboxil was appropriate. Based on a PK study, clinical data including dosing regimen developed in Japan were adequately extrapolated to Korea, supporting the approval of baloxavir marboxil in Korean as a new treatment option for influenza.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Baloxavir marboxil, a novel influenza therapeutic agent, has been approved in Japan (first global approval; February 2018) and in the United States (October 2018). The recommended dosage for patients depends on body weight: 40 mg (40–80 kg), 80 mg (≥80 kg). However, no clinical data was available for adequate clinical use in the Korean population.

• WHAT QUESTION DID THIS STUDY ADDRESS?

What are the pharmacokinetic characteristics of baloxavir acid in Koreans, and will it show similar characteristics to those in Japanese?

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Pharmacokinetics of baloxavir acid were similar to those of Japanese population. Simulated exposures to baloxavir acid demonstrated that the body weight‐based dosing regimen for baloxavir marboxil was appropriate in Korean population. This study provided the pharmacokinetic data to support the approval of baloxavir marboxil in Korea (November 2019) as a new treatment option for influenza.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Based on this pharmacokinetic study, the efficacy, safety, and body weight‐based dosing regimen data developed in foreign countries could be adequately extrapolated to Korea.     

Effect of difelikefalin,a selective kappa opioid receptor agonist,on respiratory depression: A randomized,double‐blind,placebo‐controlled trial

Difelikefalin, a selective kappa opioid receptor agonist designed to limit central nervous system (CNS) penetration, is under development for the treatment of pruritus. Its hydrophilic, small‐peptidic structure limits CNS entry, minimizing potential CNS‐mediated adverse events (AEs). This study assessed the effect of difelikefalin on key relevant measures of respiratory depression in healthy volunteers. This single‐center, randomized, double‐blind, placebo‐controlled, three‐way crossover study enrolled healthy, nonsmoking volunteers. Subjects were randomized to 1 of 3 treatment sequences of difelikefalin (1.0 or 5.0 mcg/kg i.v.) or placebo on sequential days with an intervening 24 (±2) h washout period. The primary end points included incidence of increased end‐tidal carbon dioxide (ETCO₂) greater than or equal to 10 mm Hg versus baseline or a level greater than 50 mm Hg sustained greater than or equal to 30 seconds, and incidence of reduction in saturation of peripheral oxygen (SpO₂) to less than 92% sustained greater than or equal to 30 seconds. Secondary end points included incidence of reduced respiratory rate and other safety assessments. Fifteen subjects were randomized and completed the study. No subject on placebo or difelikefalin met the increased ETCO₂ or reduced SpO₂ primary end point criteria for respiratory depression. All respiratory measures in each group remained near baseline values during 4‐h postdose observations. No subject met the reduced respiratory rate criterion or experienced clinically significant changes in ETCO₂, SpO₂, or respiratory rate. The most commonly reported treatment‐emergent AEs (TEAEs; ≥20% of subjects) were paresthesia, hypoesthesia, and somnolence in the difelikefalin arms. All TEAEs were mild and resolved without intervention. Difelikefalin 1.0 and 5.0 mcg/kg i.v. did not produce respiratory depression.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Severe respiratory depression is a life‐threatening complication of inappropriate use of mu opioid receptor agonists. Difelikefalin, a peripherally restricted kappa opioid receptor (KOR) agonist, has not demonstrated evidence of compromised respiratory safety.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This study evaluated whether difelikefalin, a selective and potent KOR agonist, induces respiratory depression.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

This study helps to expand on the safety profile for difelikefalin. Difelikefalin did not produce respiratory depression in healthy volunteers at doses that were 2 to 10 times higher than those observed to be therapeutically effective in clinical trials of patients with chronic kidney disease–associated pruritus.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

KOR agonists may be potentially safe and effective therapeutics. Difelikefalin is currently being evaluated for chronic kidney disease‐associated pruritus and other chronic pruritic conditions.     

Pharmacometabonomic association of cyclophosphamide 4‐hydroxylation in hematopoietic cell transplant recipients

The widely used alkylating agent cyclophosphamide (CY) has substantive interpatient variability in the area under the curve (AUC) of it and its metabolites. Numerous factors may influence the drug‐metabolizing enzymes that metabolize CY to 4‐hydroxycyclophosphamide (4HCY), the principal precursor to CY’s cytotoxic metabolite. We sought to identify endogenous metabolomics compounds (EMCs) associated with 4HCY formation clearance (ratio of 4HCY/CY AUC) using global metabolomics. Patients who undergo hematopoietic cell transplantation receiving post‐transplant CY (PT‐CY) were enrolled, cohort 1 (n = 26) and cohort 2 (n = 25) donating longitudinal blood samples before they started HCT (pre‐HCT), before infusion of the donor allograft (pre‐graft), before the first dose of PT‐CY (pre‐CY), and 24 h after the first dose of PT‐CY (24‐h post‐CY), which is also immediately before the second dose of CY. A total of 512 and 498 EMCs were quantitated in two cohorts, respectively. Both univariate linear regression with false discovery rate (FDR), and pathway enrichment analyses using a global association test were performed. At the pre‐CY time point, no EMCs were associated at FDR less than 0.1. At pre‐HCT, cohort 1 had one EMC (levoglucosan) survive the FDR threshold. At pre‐graft, cohort 1 and cohort 2 had 20 and 13 EMCs, respectively, exhibiting unadjusted p values less than 0.05, with the only EMCs having an FDR less than 0.1 being two unknown EMCs. At 24‐h post‐CY, there were three EMCs, two ketones, and threitol, at FDR less than 0.1 in cohort 2. These results demonstrate the potential of pharmacometabonomics, but future studies in larger samples are needed to optimize CY.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

We report the first pharmacometabonomic study of the association of plasma EMCs with cyclophosphamide pharmacokinetics, specifically the ratio of 4HCY/CY AUC.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This study addresses the question regarding if EMCs in the plasma before PT‐CY administration are associated with the ratio of 4HCY/CY AUC.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

This study adds to our knowledge that longitudinal collection of plasma EMC samples is feasible in HCT patients receiving PT‐CY. In addition, the plasma EMC changes over the ~21‐day time period that starts pre‐HCT to 24‐hr after the first PT‐CY dose.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

This study demonstrates the possibility of pharmacometabolomic research to evaluate the pharmacokinetics of a drug – in this case, cyclophosphamide – with a complex pharmacokinetic disposition.     

Polypharmacy influences the renal composite outcome in patients treated with sodium‐glucose cotransporter 2 inhibitors

Polypharmacy is a serious concern in general practice, especially among elder patients; however, the evidence showing significantly poor renal outcomes is not sufficient. This survey was performed to evaluate the effect of polypharmacy on the incidence of the renal composite outcome among a sample of patients with sodium‐glucose cotransporter 2 inhibitor (SGLT2i) treatment. We assessed 624 Japanese patients with type 2 diabetes mellitus (T2DM) and chronic kidney disease who received SGLT2i treatment for greater than 1 year. The patients were classified as those with concomitant treatment, that was limited to the medications for hypertension, T2DM, and dyslipidemia, with greater than or equal to seven medications (n = 110) and those with less than seven medications (n = 514). Evaluation of the renal composite outcome was performed by propensity score matching and stratification into quintiles. A subgroup analysis of patients of greater than or equal to 62 years of age and less than 62 years of age was also performed. The incidence of the renal composite outcome was larger in patients with greater than or equal to seven medications than in those with less than seven medications in the propensity score‐matched cohort model (6% vs. 17%, respectively, p = 0.007) and also in the quintile‐stratified analysis (odds ratio [OR], 2.23, 95% confidence interval [CI, 1.21–4.12, p = 0.01). The quintile‐stratified analysis of patients of less than 62 years of age—but not those of greater than or equal to 62 years of age—also showed a significant difference (OR, 3.29, 95% CI, 1.41–7.69, p = 0.006). Polypharmacy appears to be associated to the incidence of the renal composite outcome, especially in young patients.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Polypharmacy is an unaddressed concern and may worsen prognosis in clinical practice, especially in elderly patients.

• WHAT QUESTION DID THIS STUDY ADDRESS?

The evidence that polypharmacy correlates with poor cardiovascular or renal outcomes is insufficient in clinical practice.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

This study clarified the relationship between polypharmacy and a renal composite outcome in patients with type 2 diabetes mellitus and chronic kidney disease receiving sodium‐glucose cotransporter 2 inhibitor treatment, especially in young patients.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Both specialists and general practitioners should pay attention to polypharmacy to improve renal outcomes in clinical practice.     

Effects of 5‐HT₃ receptor antagonists on cisplatin‐induced kidney injury

Nausea, vomiting, and renal injury are the common adverse effects associated with cisplatin. Cisplatin is excreted via the multidrug and toxin release (MATE) transporter, and the involvement of the MATE transporter in cisplatin‐induced kidney injury has been reported. The MATE transporter is also involved in the excretion of ondansetron, but the effects of 5‐HT₃ receptor antagonists used clinically for cisplatin‐induced renal injury have not been elucidated. Therefore, the aim of this study was to investigate the effects of 5‐HT₃ receptor antagonists in a mouse model of cisplatin‐induced kidney injury and to validate the results using medical big data analysis of more than 1.4 million reports and a survey of 3000 hospital medical records. The concomitant use of a first‐generation 5‐HT₃ receptor antagonist (ondansetron, granisetron, or ramosetron) significantly increased cisplatin accumulation in the kidneys and worsened renal damage. Conversely, the concomitant use of palonosetron had no effect on renal function compared with the use of cisplatin alone. Furthermore, an analysis of data from the US Food and Drug Administration Adverse Event Reporting System and retrospective medical records revealed that the combination treatment of cisplatin and a first‐generation 5‐HT₃ receptor antagonist significantly increased the number of reported renal adverse events compared with the combination treatment of cisplatin and a second‐generation 5‐HT₃ receptor antagonist. These results suggest that compared with the first‐generation antagonists, second‐generation 5‐HT₃ receptor antagonists do not worsen cisplatin‐induced acute kidney injury. The findings should be validated in a prospective controlled trial before implementation in clinical practice.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

The involvement of the multidrug and toxin release (MATE) transporter in cisplatin‐induced kidney injury has been reported. The MATE transporter is involved in the excretion of not only cisplatin but also ondansetron, a 5‐HT₃ receptor antagonist used as an antiemetic; however, the effects of 5‐HT₃ receptor antagonists used clinically for cisplatin‐induced renal injury have not been elucidated.

• WHAT QUESTION DID THIS STUDY ADDRESS?

The aim of this study was to investigate the effects of 5‐HT₃ receptor antagonists in a mouse model of cisplatin‐induced kidney injury and to validate the results using medical big data analysis of more than 1.4 million reports and a survey of 3000 hospital medical records.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

The results suggest that compared with the first‐generation antagonists, second‐generation 5‐HT₃ receptor antagonists do not worsen cisplatin‐induced acute kidney injury.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Promoting the use of second‐generation 5‐HT₃ receptor antagonists is expected to reduce the number of patients who develop cisplatin‐induced renal damage.     

HLA variants associated with azathioprine‐induced pancreatitis in patients with Crohn’s disease

The immunosuppressant drug azathioprine is associated with a 4% risk of acute pancreatitis in patients with inflammatory bowel disease (IBD). Studies have demonstrated an increased risk in carriers of HLA‐DQA1*02:01 and HLA‐DRB1*07:01. We investigated whether these human leukocyte antigen (HLA) types were associated with azathioprine‐induced pancreatitis also in Swedish patients with IBD, and whether the type of disease affected the association. Nineteen individuals with IBD who developed acute pancreatitis after initiation of azathioprine were genotyped and compared with a population control cohort (n = 4891) and a control group matched for disease (n = 81). HLA‐DQA1*02:01 and HLA‐DRB1*07:01 were in full linkage disequilibrium, and were significantly associated with acute pancreatitis both when cases were compared with population controls (OR 3.97 [95% CI 1.57–9.97], p = 0.0035) and matched controls (OR 3.55 [95% CI 1.23–10.98], p = 0.0275). In a disease‐specific analysis, the correlation was positive in patients with Crohn''s disease versus matched controls (OR 9.27 [95% CI 1.86–46.19], p = 0.0066), but not in those with ulcerative colitis versus matched controls (OR 0.69 [95% CI 0.07–6.74], p = 0.749). In patients with Crohn''s disease, we estimated the conditional risk of carriers of HLA‐DQA1*02:01‐HLA‐DRB1*07:01 to 7.3%, and the conditional risk of a non‐carrier to 2.2%. We conclude that HLA‐DQA1*02:01‐HLA‐DRB1*07:01 is a marker for increased risk of acute pancreatitis in individuals of Swedish genetic origin, treated with azathioprine for Crohn''s disease.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

HLA‐DQA1*02:01 and HLA‐DRB1*07:01 have been shown to increase the risk of acute pancreatitis in individuals with inflammatory bowel disease (IBD) treated with azathioprine.

• WHAT QUESTION DID THIS STUDY ADDRESS?

It is unknown whether this risk also applies to patients of Swedish origin and if the risk differs depending on type of IBD.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

We show that HLA‐DQA1*02:01 and HLA‐DRB1*07:01 are risk markers for azathioprine‐induced acute pancreatitis in patients of Swedish origin. We propose that this risk could be restricted to those with Crohn''s disease, where the estimated risk equals 7.3% for carriers and 2.2% for non‐carriers.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

As the HLA‐DQA1*02:01‐HLA‐DRB1*07:01 haplotype has a frequency of ~7% in the Swedish population, preemptive HLA‐typing could be useful for the selection of patients with Crohn''s disease that need intensified monitoring or for choice of a different therapy.