Exposure-Response Analysis of the Sodium-Glucose Cotransporter-2 Inhibitors Dapagliflozin and Empagliflozin on Kidney Hemodynamics in Patients with Type 2 Diabetes.

Sodium-glucose cotransporter-2 (SGLT2) inhibitors improve markers for renal and cardiovascular outcomes in patients with and without type 2 diabetes (T2D). To assess whether individual differences in plasma drug exposure can explain inter-individual response variation, we characterized the exposure-response relationship for two SGLT2 inhibitors on several clinical and kidney hemodynamic variables. Data were obtained from two studies, RED and RECOLAR, assessing the effects of once-daily 10 mg dapagliflozin or empagliflozin, respectively, on kidney hemodynamics in patients with T2D. Individual plasma exposure was estimated using non-compartmental analyses and exposure-response relationships were assessed using linear mixed-effects models. In 23 patients participating in RED, the dapagliflozin geometric mean apparent area under the concentration-time curve during one dosing interval at steady state (AUC0-tau,ss) was 1153.1 µg/L*h (coefficient of variation (CV) 81.8%) and associated, per doubling, with decreases in body weight (0.29 kg, p < 0.001), systolic blood pressure (0.80 mmHg, p = 0.002), measured glomerular filtration rate (mGFR) (0.83 mL/min, p = 0.03), and filtration fraction (0.09%, p = 0.04). In 20 patients participating in RECOLOR, the empagliflozin geometric mean AUC0-tau,ss was 2035.7 nmol/L*h (CV 48.4%) and associated, per doubling, with decreases in body weight (0.13 kg, p = 0.002), systolic blood pressure (0.65 mmHg, p = 0.045), and mGFR (0.78 mL/min, p = 0.002). To conclude, dapagliflozin and empagliflozin plasma exposure was highly variable between patients and associated with inter-individual variation in response variables.

Glycemic Control and Effects of Canagliflozin in Reducing Albuminuria and eGFR: A Post Hoc Analysis of the CREDENCE Trial.

BACKGROUND: In the Canagliflozin and Renal Events in Diabetes with Established Nephropathy Clinical Evaluation (CREDENCE) trial, the sodium-glucose cotransporter-2 (SGLT2) inhibitor canagliflozin improved kidney and cardiovascular outcomes and reduced the rate of estimated glomerular filtration decline (eGFR slope) in patients with type 2 diabetes and CKD. In other clinical trials of patients with CKD or heart failure, the protective effects of SGLT2 inhibitors on eGFR slope were greater in participants with versus participants without type 2 diabetes. This post hoc analysis of the CREDENCE trial assessed whether the effects of canagliflozin on eGFR slope varied according to patient subgroups by baseline glycated hemoglobin A1c (HbA1c). METHODS: CREDENCE ( ClinicalTrials.gov [ NCT02065791 ]) was a randomized controlled trial in adults with type 2 diabetes with an HbA1c of 6.5%-12.0%, an eGFR of 30-90 ml/min per 1.73 m 2 , and a urinary albumin-to-creatinine ratio of 300-5000 mg/g. Participants were randomly assigned to canagliflozin 100 mg once daily or placebo. We studied the effect of canagliflozin on eGFR slope using linear mixed-effects models. RESULTS: The annual difference in total eGFR slope was 1.52 ml/min per 1.73 m 2 (95% confidence interval [CI], 1.11 to 1.93) slower in participants randomized to canagliflozin compared with placebo. The rate of eGFR decline was faster in those with poorer baseline glycemic control. The mean difference in total eGFR slope between canagliflozin and placebo was greater in participants with poorer baseline glycemic control (difference in eGFR slope of 0.39, 1.36, 2.60, 1.63 ml/min per 1.73 m 2 for HbA1c subgroups 6.5%-7.0%, 7.0%-8.0%, 8.0%-10.0%, 10.0%-12.0%, respectively; Pinteraction = 0.010). The mean difference in change from baseline in urinary albumin-to-creatinine ratio between participants randomized to canagliflozin and placebo was smaller in patients with baseline HbA1c 6.5%-7.0% (-17% [95% CI, -28 to -5]) compared with those with an HbA1c of 7.0%-12% (-32% [95% CI, -40 to -28]; Pinteraction = 0.03). CONCLUSIONS: The effect of canagliflozin on eGFR slope in patients with type 2 diabetes and CKD was more pronounced in patients with higher baseline HbA1c, partly because of the more rapid decline in kidney function in these individuals. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: Evaluation of the Effects of Canagliflozin on Renal and Cardiovascular Outcomes in Participants With Diabetic Nephropathy (CREDENCE), NCT02065791.

Feasibility Study to Assess Canagliflozin Distribution and Sodium-Glucose Co-Transporter 2 Occupancy Using [18 F]Canagliflozin in Patients with Type 2 Diabetes.

Sodium-glucose co-transporter 2 (SGLT2) inhibitors, including canagliflozin, reduce the risk of cardiovascular and kidney outcomes in patients with and without type 2 diabetes, albeit with a large interindividual variation. The underlying mechanisms for this variation in response might be attributed to differences in SGLT2 occupancy, resulting from individual variation in plasma and tissue drug exposure and receptor availability. We performed a feasibility study for the use of [18 F]canagliflozin positron emission tomography (PET) imaging to determine the association between clinical canagliflozin doses and SGLT2 occupancy in patients with type 2 diabetes. We obtained two 90-minute dynamic PET scans with diagnostic intravenous [18 F]canagliflozin administration and a full kinetic analysis in 7 patients with type 2 diabetes. Patients received 50, 100, or 300 mg oral canagliflozin (n = 2:4:1) 2.5 hours before the second scan. Canagliflozin pharmacokinetics and urinary glucose excretion were measured. The apparent SGLT2 occupancy was derived from the difference between the apparent volume of distribution of [18 F]canagliflozin in the baseline and post-drug PET scans. Individual canagliflozin area under the curve from oral dosing until 24-hours (AUCP0-24h ) varied largely (range 1,715-25,747 µg/L*hour, mean 10,580 µg/L*hour) and increased dose dependently with mean values of 4,543, 6,525, and 20,012 µg/L*hour for 50, 100, and 300 mg, respectively (P = 0.046). SGLT2 occupancy ranged between 65% and 87%, but did not correlate with canagliflozin dose, plasma exposure, or urinary glucose excretion. We report the feasibility of [18 F]canagliflozin PET imaging to determine canagliflozin kidney disposition and SGLT2 occupancy. This suggests the potential of [18 F]canagliflozin as a tool to visualize and quantify clinically SGLT2 tissue binding.

Studying Telmisartan Plasma Exposure, Kidney Distribution, Receptor Occupancy, and Response in Patients With Type 2 Diabetes Using [11 C]Telmisartan.

The angiotensin receptor blocker telmisartan slows progression of kidney disease in patients with type 2 diabetes (T2D), yet many patients remain at high risk for progressive kidney function loss. The underlying mechanisms for this response variation might be attributed to differences in angiotensin-1 receptor occupancy (RO), resulting from individual variation in plasma drug exposure, tissue drug exposure, and receptor availability. Therefore, we first assessed the relationship between plasma telmisartan exposure and urinary-albumin-to-creatinine-ratio (UACR) in 10 patients with T2D and albuminuria (mean age 66 years, median UACR 297 mg/g) after 4 weeks treatment with 80 mg telmisartan once daily. Increasing telmisartan exposure associated with a larger reduction in UACR (Pearson correlation coefficient (PCC) = -0.64, P = 0.046, median change UACR: -40.1%, 95% confidence interval (CI): -22.9 to -77.4%, mean telmisartan area under the curve (AUC) = 2927.1 ng·hour/mL, 95% CI: 723.0 to 6501.6 ng·hour/mL). Subsequently, we assessed the relation among plasma telmisartan exposure, kidney distribution, and angiotensin-1 RO in five patients with T2D (mean age 60 years, median UACR 72 mg/g) in a separate positron emission tomography imaging study with [11 C]Telmisartan. Individual plasma telmisartan exposure correlated with telmisartan distribution to the kidneys (PCC = 0.976, P = 0.024). A meaningful RO could be calculated in three patients receiving 120 mg oral telmisartan, and although high exposure seems related to higher RO, with AUC0-last of 31, 840, and 274 ng·hour/mL and corresponding RO values 5.5%, 44%, and 59%, this was not significant (P = 0.64). Together these results indicate, for the first time, a relationship among interindividual differences in plasma exposure, kidney tissue distribution, RO, and ultimately UACR response after telmisartan administration.

Current Use and Complementary Value of Combining in Vivo Imaging Modalities to Understand the Renoprotective Effects of Sodium-Glucose Cotransporter-2 Inhibitors at a Tissue Level.

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) were initially developed to treat diabetes and have been shown to improve renal and cardiovascular outcomes in patients with- but also without diabetes. The mechanisms underlying these beneficial effects are incompletely understood, as is the response variability between- and within patients. Imaging modalities allow in vivo quantitative assessment of physiological, pathophysiological, and pharmacological processes at kidney tissue level and are therefore increasingly being used in nephrology. They provide unique insights into the renoprotective effects of SGLT2i and the variability in response and may thus contribute to improved treatment of the individual patient. In this mini-review, we highlight current work and opportunities of renal imaging modalities to assess renal oxygenation and hypoxia, fibrosis as well as interaction between SGLT2i and their transporters. Although every modality allows quantitative assessment of particular parameters of interest, we conclude that especially the complementary value of combining imaging modalities in a single clinical trial aids in an integrated understanding of the pharmacology of SGLT2i and their response variability.

GMP Compliant Synthesis of [18F]Canagliflozin, a Novel PET Tracer for the Sodium-Glucose Cotransporter 2.

Inhibition of the sodium-glucose cotransporter 2 (SGLT2) by canagliflozin in type 2 diabetes mellitus results in large between-patient variability in clinical response. To better understand this variability, the positron emission tomography (PET) tracer [18F]canagliflozin was developed via a Cu-mediated 18F-fluorination of its boronic ester precursor with a radiochemical yield of 2.0 ± 1.9% and a purity of >95%. The GMP automated synthesis originated [18F]canagliflozin with a yield of 0.5-3% (n = 4) and a purity of >95%. Autoradiography showed [18F]canagliflozin binding in human kidney sections containing SGLT2. Since [18F]canagliflozin is the isotopologue of the extensively characterized drug canagliflozin and thus shares its toxicological and pharmacological characteristics, it enables its immediate use in patients.

Predictors of new fragility fractures after diagnosis of indolent systemic mastocytosis.

BACKGROUND: Fragility fractures (FFxs) and osteoporosis occur frequently in patients with indolent systemic mastocytosis (ISM), even before 50 years of age. OBJECTIVE: We sought to develop a prediction model to identify individual patients with ISM at risk of new FFxs. METHODS: Data on lifetime fractures and trauma circumstances were collected from vertebral morphometry, patients' records, and questionnaires. Clinical, lifestyle, and bone characteristics were measured. Patients receiving treatment for osteoporosis before ISM diagnosis or with missing bone data were excluded from FFx risk assessment. RESULTS: In total, 389 lifetime fractures occurred in 127 of the 221 patients with ISM (age, 19-77 years), including 90 patients with 264 FFxs. Median follow-up after diagnosis was 5.4 years (range, 0.4-15.3 years), with 5- and 10-year FFx risks of 23% ± 3% and 31% ± 4%, respectively. Male sex, high levels of bone resorption (serum type I collagen C-telopeptide), low hip bone mineral density, absence of urticaria pigmentosa, and alcohol intake at the time of ISM diagnosis were independent predictors of future FFxs. The MastFx score, a prediction model using these 5 characteristics, showed good accuracy (area under the curve, 0.80) to determine the risk of new FFxs. QFracture, a validated risk scoring tool for persons aged 30 to 99 years, was not useful in patients with ISM. CONCLUSION: The MastFx score distinguishes patients with ISM at high, intermediate, and low risk of new FFxs. The included characteristics sex, serum type I collagen C-telopeptide, hip bone mineral density, urticaria pigmentosa, and alcohol intake are easy to collect in clinical practice. The high occurrence of FFxs in patients with ISM underlines the importance of optimizing bone quality and early start of therapeutic prevention in patients at risk.