Best Practices and Considerations for Clinical Pharmacology and Pharmacometric Aspects for Optimal Development of CAR-T and TCR-T Cell Therapies: An Industry Perspective.

With the promise of a potentially "single dose curative" paradigm, CAR-T cell therapies have brought a paradigm shift in the treatment and management of hematological malignancies. Both CAR-T and TCR-T cell therapies have also made great progress toward the successful treatment of solid tumor indications. The field is rapidly evolving with recent advancements including the clinical development of "off-the-shelf" allogeneic CAR-T therapies that can overcome the long and difficult "vein-to-vein" wait time seen with autologous CAR-T therapies. There are unique clinical pharmacology, pharmacometric, bioanalytical, and immunogenicity considerations and challenges in the development of these CAR-T and TCR-T cell therapies. Hence, to help accelerate the development of these life-saving therapies for the patients with cancer, experts in this field came together under the umbrella of International Consortium for Innovation and Quality in Pharmaceutical Development (IQ) to form a joint working group between the Clinical Pharmacology Leadership Group (CPLG) and the Translational and ADME Sciences Leadership Group (TALG). In this white paper, we present the IQ consortium perspective on the best practices and considerations for clinical pharmacology and pharmacometric aspects toward the optimal development of CAR-T and TCR-T cell therapies.

Evolution of preclinical characterization and insights into clinical pharmacology of checkpoint inhibitors approved for cancer immunotherapy.

Cancer immunotherapy has significantly advanced the treatment paradigm in oncology, with approvals of immuno-oncology agents for over 16 indications, many of them first line. Checkpoint inhibitors (CPIs) are recognized as an essential backbone for a successful anticancer therapy regimen. This review focuses on the US Food and Drug Administration (FDA) regulatory approvals of major CPIs and the evolution of translational advances since their first approval close to a decade ago. In addition, critical preclinical and clinical pharmacology considerations, an overview of the pharmacokinetic and dose/regimen aspects, and a discussion of the future of CPI translational and clinical pharmacology as combination therapy becomes a mainstay of industrial immunotherapy development and in clinical practice are also discussed.

Phase I Open-Label Study Evaluating the Safety, Pharmacokinetics, and Preliminary Efficacy of Dilpacimab in Patients with Advanced Solid Tumors.

Dilpacimab (formerly ABT-165), a novel dual-variable domain immunoglobulin, targets both delta-like ligand 4 (DLL4) and VEGF pathways. Here, we present safety, pharmacokinetic (PK), pharmacodynamic (PD), and preliminary efficacy data from a phase I study (trial registration ID: NCT01946074) of dilpacimab in patients with advanced solid tumors. Eligible patients (≥18 years) received dilpacimab intravenously on days 1 and 15 in 28-day cycles at escalating dose levels (range, 1.25-7.5 mg/kg) until progressive disease or unacceptable toxicity. As of August 2018, 55 patients with solid tumors were enrolled in the dilpacimab monotherapy dose-escalation and dose-expansion cohorts. The most common treatment-related adverse events (TRAE) included hypertension (60.0%), headache (30.9%), and fatigue (21.8%). A TRAE of special interest was gastrointestinal perforation, occurring in 2 patients (3.6%; 1 with ovarian and 1 with prostate cancer) and resulting in 1 death. The PK of dilpacimab showed a half-life ranging from 4.9 to 9.5 days, and biomarker analysis demonstrated that the drug bound to both VEGF and DLL4 targets. The recommended phase II dose for dilpacimab monotherapy was established as 3.75 mg/kg, primarily on the basis of tolerability through multiple cycles. A partial response was achieved in 10.9% of patients (including 4 of 16 patients with ovarian cancer). The remaining patients had either stable disease (52.7%), progressive disease (23.6%), or were deemed unevaluable (12.7%). These results demonstrate that dilpacimab monotherapy has an acceptable safety profile, with clinical activity observed in patients with advanced solid tumors.

A Population Pharmacokinetic Meta-Analysis of Veliparib, a PARP Inhibitor, Across Phase 1/2/3 Trials in Cancer Patients.

Veliparib (ABT-888) is a poly(ADP-ribose) polymerase inhibitor in development for the treatment of high-grade ovarian cancer or BRCA-mutated breast cancer in combination with carboplatin and paclitaxel. The population pharmacokinetics of veliparib were characterized using combined data from 1470 adult subjects with ovarian cancer, breast cancer, or other solid tumors enrolled in 6 phase 1 studies, 1 phase 2 study, and 2 phase 3 studies of veliparib oral doses of 10 to 400 mg twice daily as monotherapy or in combination with chemotherapy. A 1-compartment model with linear clearance and first-order absorption best characterized veliparib pharmacokinetics. The predicted apparent oral clearance (CL/F) and volume of distribution (Vc /F) were 479 L/day and 152 L, respectively. The significant covariates in the final model included albumin, creatinine clearance, strong inhibitors of cytochrome P450 (CYP) 2D6, and sex on CL/F and albumin, body weight, and sex on Vc /F. Mild and moderate renal impairment increased veliparib median (95%CI) steady-state AUC (AUCss ) by 27.3% (23.7%-30.9%) and 65.4% (56.0%-75.5%), respectively, compared with normal renal function. Male subjects had 16.5% (7.53%-23.9%) lower AUCss compared with female subjects and coadministration with strong CYP2D6 inhibitors increased AUCss by 13.0% (6.11%-20.8%). Race, age, region, cancer type, or enzyme (CYP3A4, CYP2C19) or transporter (P-glycoprotein, multidrug and toxin extrusion protein 1/2, organic cation transporter 2) inhibiting/inducing comedications were not found to significantly impact veliparib pharmacokinetics. Other than baseline creatinine clearance and hence renal impairment effect on veliparib clearance, no other covariates had a clinically meaningful effect on veliparib exposure warranting dose adjustment.

Model Informed Dosing Regimen and Phase I Results of the Anti-PD-1 Antibody Budigalimab (ABBV-181).

Budigalimab is a humanized, recombinant, Fc mutated IgG1 monoclonal antibody targeting programmed cell death 1 (PD-1) receptor, currently in phase I clinical trials. The safety, efficacy, pharmacokinetics (PKs), pharmacodynamics (PDs), and budigalimab dose selection from monotherapy dose escalation and multihistology expansion cohorts were evaluated in patients with previously treated advanced solid tumors who received budigalimab at 1, 3, or 10 mg/kg intravenously every 2 weeks (Q2W) in dose escalation, including Japanese patients that received 3 and 10 mg/kg Q2W. PK modeling and PK/PD assessments informed the dosing regimen in expansion phase using data from body-weight-based dosing in the escalation phase, based on which patients in the multihistology expansion cohort received flat doses of 250 mg Q2W or 500 mg every four weeks (Q4W). Immune-related adverse events (AEs) were reported in 11 of 59 patients (18.6%), of which 1 of 59 (1.7%) was considered grade ≥ 3 and the safety profile of budigalimab was consistent with other PD-1 targeting agents. No treatment-related grade 5 AEs were reported. Four responses per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 were reported in the dose escalation cohort and none in the multihistology expansion cohort. PK of budigalimab was approximately dose proportional and sustained > 99% peripheral PD-1 receptor saturation was observed by 2 hours postdosing, across doses. PK/PD and safety profiles were comparable between Japanese and Western patients, and exposure-safety analyses did not indicate any trends. Observed PK and PD-1 receptor saturation were consistent with model predictions for flat doses and less frequent regimens, validating the early application of PK modeling and PK/PD assessments to inform the recommended dose and regimen, following dose escalation.

Informing Development of Bispecific Antibodies Using Physiologically Based Pharmacokinetic-Pharmacodynamic Models: Current Capabilities and Future Opportunities.

Antibody therapeutics continue to represent a significant portion of the biotherapeutic pipeline, with growing promise for bispecific antibodies (BsAbs). BsAbs can target 2 different antigens at the same time, such as simultaneously binding tumor-cell receptors and recruiting cytotoxic immune cells. This simultaneous engagement of 2 targets can be potentially advantageous, as it may overcome disadvantages posed by a monotherapy approach, like the development of resistance to treatment. Combination therapy approaches that modulate 2 targets simultaneously offer similar advantages, but BsAbs are more efficient to develop. Unlike combination approaches, BsAbs can facilitate spatial proximity of targets that may be necessary to induce the desired effect. Successful development of BsAbs requires understanding antibody formatting and optimizing activity for both targets prior to clinical trials. To realize maximal efficacy, special attention is required to fully define pharmacokinetic (PK)/pharmacodynamic (PD) relationships enabling selection of dose and regimen. The application of physiologically based pharmacokinetics (PBPK) has been evolving to inform the development of novel treatment modalities such as bispecifics owing to the increase in our understanding of pharmacology, utility of multiscale models, and emerging clinical data. In this review, we discuss components of PBPK models to describe the PK characteristics of BsAbs and expand the discussion to integration of PBPK and PD models to inform development of BsAbs. A framework that can be adopted to build PBPK-PD models to inform the development of BsAbs is also proposed. We conclude with examples that highlight the application of PBPK-PD and share perspectives on future opportunities for this emerging quantitative tool.

Influence of Renal Function on Evolocumab Exposure, Pharmacodynamics, and Safety.

We evaluated the pharmacokinetics, pharmacodynamics, and safety of evolocumab, a fully human monoclonal antibody against proprotein convertase subtilisin kexin type 9 (PCSK9), in an open-label, parallel-design study in participants with normal renal function (n = 6), severe renal impairment (RI; n = 6), or end-stage renal disease (ESRD) receiving hemodialysis (n = 6) who received a single 140-mg dose of evolocumab. The effects of evolocumab treatment on low-density lipoprotein cholesterol (LDL-C) lowering and unbound PCSK9 concentrations were similar in the normal renal function group and the renally impaired groups. Geometric mean Cmax and AUClast values in the severe RI and ESRD hemodialysis groups compared with the normal renal function group were lower but within 37% of the normal renal function group (Jonckheere-Terpstra trend test; Cmax , P = .23; AUClast , P = .22) and within 26% after adjusting for body weight (mean body weight was approximately 9% higher in the renally impaired groups compared with the normal renal function group). No correlations were observed between exposure and baseline creatinine clearance. No adverse event was determined by the investigators to be related to evolocumab, and there were no trends indicative of clinically important effects on laboratory variables or vital signs. Overall, there were no meaningful differences in evolocumab exposure, as assessed by Cmax and AUClast , in patients with severe RI and ESRD hemodialysis compared with patients with normal renal function, and LDL-C-lowering effects were similar across groups. These results support the use of evolocumab without dose adjustment in patients who have severe RI or ESRD.

Reverse Translation: The Art of Cyclical Learning.

We live in an era of precision therapeutics, value-based healthcare, patient-participatory research, and enhanced clinical trial transparency, with explosive increases in our ability to access and analyze multiscale biological and clinical data from diverse ecosystems. To discover and develop truly transformative medicines with a patient-centric sense of urgency, we will need to exploit data that lie far beyond the confines of laboratory-based experimental models and controlled clinical trials, dynamically maximizing the value of information in real-world data from clinical practice settings and even social media. This demands commitment to a culture that embraces Reverse Translation as a critical component of the practice of Translational Medicine in the discovery, development, regulation, and utilization of therapeutics.

Clinical Pharmacokinetics and Pharmacodynamics of Evolocumab, a PCSK9 Inhibitor.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) increases plasma low-density lipoprotein cholesterol (LDL-C) by decreasing expression of the LDL receptor on hepatic cells. Evolocumab is a human monoclonal immunoglobulin G2 that binds specifically to human PCSK9 to reduce LDL-C. Evolocumab exhibits nonlinear kinetics as a result of binding to PCSK9. Elimination is predominantly through saturable binding to PCSK9 at lower concentrations and a nonsaturable proteolytic pathway at higher concentrations. The effective half-life of evolocumab is 11-17 days. The pharmacodynamic effects of evolocumab on PCSK9 are rapid, with maximum suppression within 4 h. At steady state, peak reduction of LDL-C occurs approximately 1 week after a subcutaneous dose of 140 mg every 2 weeks (Q2W) and 2 weeks after a subcutaneous dose 420 mg once monthly (QM), and returns towards baseline over the dosing interval. In several clinical studies, these doses of evolocumab reduced LDL-C by approximately 55-75% compared with placebo. Evolocumab also reduced lipoprotein(a) [Lp(a)] levels and improved those of other lipids in clinical studies. No clinically meaningful differences in pharmacodynamic effects on LDL-C were observed in adult subjects regardless of mild/moderate hepatic impairment, renal impairment or renal failure, body weight, race, sex, or age. No clinically meaningful differences were observed for the pharmacodynamic effects of evolocumab on LDL-C between patients who received evolocumab alone or in combination with a statin, resulting in additional lowering of LDL-C when evolocumab was combined with a statin. No dose adjustment is necessary based on patient-specific factors or concomitant medication use.

How Well Are We Applying Quantitative Methods to Reverse Translation to Inform Early Clinical Development?

If we are to improve our low success rate and rising costs in the pharmaceutical industry, we need to use every tool available. Reverse translation can particularly inform discovery and early clinical development via appropriate quantitative integration of relevant data. This commentary reports on a crowd-sourced survey (2017) that sought to evaluate the integration of reverse translation in pharma. The results indicate that these methods are being applied, to varying degrees, across most respondents.

Crowdsourced Asparagus Urinary Odor Population Kinetics.

The consumption of asparagus is associated with the production of malodorous urine with considerable interindividual variability (IIV). To characterize the urinary odor kinetics after consumption of asparagus spears, we conducted a study with consenting attendees from two American Society for Clinical Pharmacology and Therapeutics (ASCPT) meetings. Subjects were randomized to eat a specific number of asparagus spears, and then asked to report their urinary odor perception. Eighty-seven subjects were included in the final analysis. A mixed effect proportional odds model was developed that adequately characterized the dose-response relationship. We estimated the half-life of the asparagus effect on malodorous urine to be 4.7 hours (relative standard error (RSE) = 13.2%), and identified a dose-response slope term with good precision (24.3%). Age was found as the predictor of IIV in slope estimates. This study design and tools can be used as a demonstration "crowdsourcing" project for studying population kinetics in organizational and educational settings.

Bedside to Bench: Integrating Quantitative Clinical Pharmacology and Reverse Translation to Optimize Drug Development.

With so much emphasis on reducing attrition and becoming more efficient in the delivery of healthcare, there are many opportunities to leverage existing clinical data in drug development and to foster the practice of reverse translation. The application of quantitative approaches to convert clinical trial and real-world data to knowledge will continue to drive innovation. Herein we discuss recent examples of reverse translation and consider future opportunities to capture critical clinical knowledge to inform decision-making in drug development.

Assessment of pharmacokinetic interaction between rilotumumab and epirubicin, cisplatin and capecitabine (ECX) in a Phase 3 study in gastric cancer.

AIMS: Rilotumumab is a fully human monoclonal antibody investigated for the treatment of MET-positive gastric cancer. The aim of this study was to evaluate the potential pharmacokinetic (PK)-based drug-drug interaction (DDI) between rilotumumab and epirubicin (E), cisplatin(C) and capecitabine (X). METHODS: This was a Phase 3 double-blind, placebo-controlled study, in which rilotumumab, epirubicin and cisplatin were administered intravenously at 15 mg kg-1 , 50 mg m-2 , and 60 mg m-2 Q3W, respectively, while capecitabine was given orally at 625 mg m-2 twice daily. Rilotumumab PK samples were taken at pre-dose and at the end-of-infusion from all patients in cycles 1, 3, 5 and 7. ECX PK samples were taken in cycle 3 from patients who participated in the intensive PK assessment. ECX PK was assessed by non-compartmental (NCA) analyses and PK parameters were compared between two arms. Rilotumumab PK was assessed by comparing the observed rilotumumab serum concentrations with model-predicted concentrations using a population PK model developed from previous Phase 1 and Phase 2 studies. RESULTS: The study enrolled 609 patients. ECX plasma concentrations in the presence and absence of rilotumumab were similar, as demonstrated by the geometric mean ratios for Cmax and AUC, which were close to 1.0, suggesting ECX PK was not affected by co-administration of rilotumumab. The observed rilotumumab serum concentrations were similar to the values predicted by population PK modelling on the basis of a prediction-corrected visual predictive check, indicating rilotumumab exposure was not affected by co-administration of ECX. CONCLUSIONS: The results suggest lack of PK-based DDI between rilotumumab and ECX.

Exploring the potential of the SGLT2 inhibitor dapagliflozin in type 1 diabetes: a randomized, double-blind, placebo-controlled pilot study.

OBJECTIVE: Insulin adjustments to maintain glycemic control in individuals with type 1 diabetes often lead to wide glucose fluctuations, hypoglycemia, and increased body weight. Dapagliflozin, an insulin-independent sodium-glucose cotransporter 2 (SGLT2) inhibitor, increases glucosuria and reduces hyperglycemia in individuals with type 2 diabetes. The primary objective of this study was to assess short-term safety of dapagliflozin in combination with insulin; secondary objectives included pharmacokinetic, pharmacodynamic, and efficacy parameters. RESEARCH DESIGN AND METHODS: A 2-week, dose-ranging, randomized, double-blind, placebo-controlled proof-of-concept study randomly assigned 70 adults with type 1 diabetes (HbA1c 7-10%), who were receiving treatment with stable doses of insulin, to one of four dapagliflozin doses (1, 2.5, 5, or 10 mg) or placebo. The insulin dose was not proactively reduced at randomization but could be adjusted for safety reasons. RESULTS: Sixty-two patients (88.6%) completed the study. Any hypoglycemia was common across all treatments (60.0-92.3%); one major event of hypoglycemia occurred with dapagliflozin 10 mg. No diabetic ketoacidosis occurred. Pharmacokinetic parameters were similar to those observed in patients with type 2 diabetes. Glucosuria increased by 88 g/24 h (95% CI 55 to 121) with dapagliflozin 10 mg and decreased by -21.5 g/24 h (95% CI -53.9 to 11.0) with placebo. Changes from baseline with dapagliflozin 10 mg by day 7 were as follows: -2.29 mmol/L (95% CI -3.71 to -0.87 [-41.3 mg/dL; 95% CI -66.9 to -15.7]) for 24-h daily average blood glucose; -3.77 mmol/L (95% CI -6.09 to -1.45 [-63.1 mg/dL; 95% CI -111.5 to -14.8]) for mean amplitude of glycemic excursion; and -16.2% (95% CI -29.4 to -0.5) for mean percent change in total daily insulin dose. Corresponding changes with placebo were as follows: -1.13 mmol/L (95% CI -3.63 to 1.37), -0.45 mmol/L (95% CI -4.98 to 4.08), and 1.7% (95% CI -22.8 to 33.9), respectively. However, for every efficacy parameter, the 95% CIs for all dapagliflozin doses overlapped those for placebo. CONCLUSIONS: This exploratory study of dapagliflozin in adults with type 1 diabetes demonstrated acceptable short-term tolerability and expected pharmacokinetic profiles and increases in urinary glucose excretion. Within the dapagliflozin groups, dose-related reductions in 24-h glucose, glycemic variability, and insulin dose were suggested, which provide hope that SGLT2 inhibition may prove in larger randomized controlled trials to be efficacious in reducing hyperglycemia in type 1 diabetes.

Validation of 4ß-hydroxycholesterol and evaluation of other endogenous biomarkers for the assessment of CYP3A activity in healthy subjects.

AIMS: This study aimed to assess changes in the plasma concentrationss of 4ß-hydroxycholesterol (4ßHC) against intravenous (i.v.) and oral midazolam (MDZ) pharmacokinetics (PK) after administration of a potent CYP3A inhibitor [ketoconazole (KETO)] and inducer [rifampicin (RIF)]. METHODS: Thirty-two healthy subjects (HS) were allocated into three groups of 12 each in KETO and RIF and 10 in a placebo group (PLB). All HS were randomized to receive oral and i.v. MDZ on day 1 or 2 and on day 15 or 16 after receiving RIF (600 mg once daily), KETO (400 mg once daily) or PLB for 2 weeks. Subjects were followed until day 30. The effect of treatments on 4ßHC was assessed by analyzing % change from baseline using a linear spline mixed effects model. RESULTS: Compared with PLB, KETO decreased 4ßHC mean values up to 13% (P = 0.003) and RIF increased 4ßHC mean values up to 220% (P < 0.001). Within 14 days of stopping KETO and RIF, 4ßHC had either returned to baseline (KETO) or was still returning to baseline (RIF). Compared with baseline, mean oral MDZ AUC increased by 11-fold (90% CI ranging from 9-fold to 13-fold increase) and decreased by 92% (90% CI ranging from 90% to 95% decrease) after KETO and RIF, respectively. Similar trends were observed for 6ß-hydroxycortisol : cortisol (6ßHCL : CL) urinary ratios. CONCLUSIONS: Changes in plasma 4ßHC can be utilized as a surrogate for MDZ PK after multiple doses of potent CYP3A inducers. There is a more limited dynamic range for 4ßHC for assessment of potential CYP3A inhibitors. 4ßHC is a valuable tool for the assessment of potential CYP3A inducers in early drug development.

Clinical pharmacokinetics and pharmacodynamics of dapagliflozin, a selective inhibitor of sodium-glucose co-transporter type 2.

Sodium-glucose co-transporter 2 (SGLT2) is predominantly expressed in the S1 segment of the proximal tubule of the kidney and is the major transporter responsible for mediating renal glucose reabsorption. Dapagliflozin is an orally active, highly selective SGLT2 inhibitor that improves glycemic control in patients with type 2 diabetes mellitus (T2DM) by reducing renal glucose reabsorption leading to urinary glucose excretion (glucuresis). Orally administered dapagliflozin is rapidly absorbed generally achieving peak plasma concentrations within 2 h. Dose-proportional systemic exposure to dapagliflozin has been observed over a wide dose range (0.1-500 mg) with an oral bioavailability of 78 %. Dapagliflozin has extensive extravascular distribution (mean volume of distribution of 118 L). Dapagliflozin metabolism occurs predominantly in the liver and kidneys by uridine diphosphate-glucuronosyltransferase-1A9 to the major metabolite dapagliflozin 3-O-glucuronide (this metabolite is not an SGLT2 inhibitor at clinically relevant exposures). Dapagliflozin is not appreciably cleared by renal excretion (<2 % of dose is recovered in urine as parent). Dapagliflozin 3-O-glucuronide elimination occurs mainly via renal excretion, with 61 % of a dapagliflozin dose being recovered as this metabolite in urine. The half-life for orally administered dapagliflozin 10 mg was 12.9 h. Maximal increases in urinary glucose excretion were seen at doses ≥20 mg/day in patients with T2DM. No clinically relevant differences were observed in dapagliflozin exposure with respect to age, race, sex, body weight, food, or presence of T2DM. Pharmacodynamic changes are dependent on plasma glucose and renal function, and decreases in urinary glucose excretion were observed due to the lower filtered load (plasma glucose × glomerular filtration rate) in healthy volunteers compared to subjects with T2DM. After multiple doses of dapagliflozin, urinary glucose excretion was associated with dose-related decreases in plasma glucose parameters in subjects with T2DM. Patients with severe renal or hepatic impairment show higher systemic exposure to dapagliflozin. No clinically relevant drug interactions were observed that would necessitate dose adjustment of dapagliflozin when administered with other antidiabetic or cardiovascular medications, as well as drugs that could potentially influence dapagliflozin metabolism.

Pharmacokinetic and pharmacodynamic properties of single- and multiple-dose of dapagliflozin, a selective inhibitor of SGLT2, in healthy Chinese subjects.

BACKGROUND: Dapagliflozin, a selective, orally active, renal sodium glucose cotransporter 2 (SGLT2) 2 inhibitor, is under investigation as a treatment of type 2 diabetes mellitus (T2DM). Dapagliflozin reduces hyperglycemia by inhibiting renal glucose reabsorption and dose-dependently increasing urinary glucose excretion, independent of insulin secretion or action. OBJECTIVES: These studies assessed the single- and multiple-dose pharmacokinetic and pharmaco dynamic properties of dapagliflozin and its major inactive metabolite, dapagliflozin 3-O-glucuronide (D3OG), in healthy subjects residing in China. METHODS: In 2 identically designed, open-label, single- and multiple-dose studies (n = 14 for both studies), healthy Chinese subjects were administered oral dapagliflozin 5 or 10 mg. In both studies, subjects received a single dose on day 1 (single-dose administration period) followed by 6 once-daily doses on days 5 to 10 (multiple-dose administration period). Pharmacokinetic parameters (plasma and urinary dapagliflozin and D3OG), pharmacodynamic response (urinary glucose excretion), and tolerability were assessed. RESULTS: Fourteen subjects completed the dapagliflozin 5-mg study, and 13 completed the dapagliflozin 10-mg study. Baseline characteristics were balanced across the two studies: 9 versus 10 men; mean age, 27.1 versus 28.9 years; mean weight, 62.8 versus 62.2 kg; and mean body mass index, 23.0 versus 22.2 kg/m(2) in the dapagliflozin 5- and 10-mg studies, respectively. In both doses, dapagliflozin was rapidly absorbed (T(max), ≤1.5 h), accumulation (defined as the geometric mean ratio of AUC(τ) at day 10 to AUC(τ) at day 1) after multiple dosing was minimal (<1.13 fold), and elimination half-life was 10 to 12 h. D3OG showed a slightly longer median Tmax (≤2 h) but a similar plasma concentration-time profile and half-life compared with dapagliflozin. The majority of D3OG (up to 69.7% of the dapagliflozin dose) was excreted in urine, while ≤1.9% of dapagliflozin was excreted unchanged in urine. Over a 24-hour period and at steady state (day 10), urinary glucose excretion values were 28.1 and 41.1 g with dapagliflozin 5 and 10 mg, respectively. Dapagliflozin was generally well tolerated; one dapagliflozin 10 mg-treated subject discontinued the study because of a serious adverse event (bronchitis) considered by the investigator as unrelated to dapagliflozin dosing. CONCLUSIONS: Pharmacokinetic and pharmacodynamic characteristics following single- and multiple-dose dapagliflozin 5 and 10 mg oral administration in healthy Chinese subjects were as predicted from previous studies and were similar to findings observed in non-Chinese healthy subjects. Dapagliflozin dosing was well tolerated. The clinically recommended dapagliflozin dose of 10 mg once daily is expected to be appropriate in patients of Chinese ethnicity; results from an efficacy and tolerability study in Chinese patients with T2DM are awaited.

Use of low-dose clinical pharmacodynamic and pharmacokinetic data to establish an occupational exposure limit for dapagliflozin, a potent inhibitor of the renal sodium glucose co-transporter 2.

Classical risk assessment models for setting safe occupational exposure limits (OEL) have used multiple uncertainty factors (UF) applied to a point of departure (POD), e.g., a No Observed Effect Level (NOEL), which in some cases is the pharmacological effect. Dapagliflozin promotes glucosuria by inhibiting the renal sodium-glucose cotransporter-2 transporter. The initial OEL for dapagliflozin (0.002mg/m(3)) was calculated when low dose clinical data was not available to identify a NOEL resulting in the need to use excessive UFs. To reduce the UFs from the OEL, a clinical pharmacodynamic [glucosuria and urinary glucose dipstick (UGD)] and pharmacokinetic study was conducted with single oral doses of 0.001, 0.01, 0.1, 0.3, 1.0 or 2.5mg administered to 36 healthy subjects. Dose-related dapagliflozin systemic exposures were observed at doses ⩾0.1mg and glucosuria was observed at doses ⩾0.3mg and corroborated by UGD. The NOEL was therefore 0.1mg for glucosuria. For setting the new OEL, no UFs were required. Dividing the POD by 10m(3) (the volume of air an adult inhales in a workday), the resulting OEL was 0.01mg/m(3). In conclusion, low-dose clinical pharmacodynamic and pharmacokinetic data can allow the OEL to be adjusted to the highest safe level.

Characterization of renal glucose reabsorption in response to dapagliflozin in healthy subjects and subjects with type 2 diabetes.

OBJECTIVE: To examine the effect of dapagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, on the major components of renal glucose reabsorption (decreased maximum renal glucose reabsorptive capacity [TmG], increased splay, and reduced threshold), using the pancreatic/stepped hyperglycemic clamp (SHC) technique. RESEARCH DESIGN AND METHODS: Subjects with type 2 diabetes (n=12) and matched healthy subjects (n=12) underwent pancreatic/SHC (plasma glucose range 5.5-30.5 mmol/L) at baseline and after 7 days of dapagliflozin treatment. A pharmacodynamic model was developed to describe the major components of renal glucose reabsorption for both groups and then used to estimate these parameters from individual glucose titration curves. RESULTS: At baseline, type 2 diabetic subjects had elevated TmG, splay, and threshold compared with controls. Dapagliflozin treatment reduced the TmG and splay in both groups. However, the most significant effect of dapagliflozin was a reduction of the renal threshold for glucose excretion in type 2 diabetic and control subjects. CONCLUSIONS: The SGLT2 inhibitor dapagliflozin improves glycemic control in diabetic patients by reducing the TmG and threshold at which glucose is excreted in the urine.

Simultaneous oral therapeutic and intravenous ¹4C-microdoses to determine the absolute oral bioavailability of saxagliptin and dapagliflozin.

AIM: To determine the absolute oral bioavailability (F(p.o.) ) of saxagliptin and dapagliflozin using simultaneous intravenous ¹4C-microdose/therapeutic oral dosing (i.v.micro + oraltherap). METHODS: The F(p.o.) values of saxagliptin and dapagliflozin were determined in healthy subjects (n = 7 and 8, respectively) following the concomitant administration of single i.v. micro doses with unlabelled oraltherap doses. Accelerator mass spectrometry and liquid chromatography-tandem mass spectrometry were used to quantify the labelled and unlabelled drug, respectively. RESULTS: The geometric mean point estimates (90% confidence interval) F(p.o) . values for saxagliptin and dapagliflozin were 50% (48, 53%) and 78% (73, 83%), respectively. The i.v.micro had similar pharmacokinetics to oraltherap. CONCLUSIONS: Simultaneous i.v.micro + oraltherap dosing is a valuable tool to assess human absolute bioavailability.