Vikram Sinha

Pharmacokinetics/pharmacodynamics and the stages of drug development: Role of modeling and simulation

Pharmacokinetic (PK) and pharmacodynamic (PD) modeling and simulation (M&S) are well-recognized powerful tools that enable effective implementation of the learn-and-confirm paradigm in drug development. The impact of PK/PD M&S on decision making and drug development risk management is dependent on the question being asked and on the availability and quality of data accessible at a particular stage of drug development. For instance, M&S methodologies can be used to capture uncertainty and use the expected variability in PK/PD data generated in preclinical species for projection of the plausible range of clinical dose; clinical trial simulation can be used to forecast the probability of achieving a target response in patients based on information obtained in early phases of development. Framing the right question and capturing the key assumptions are critical components of the “learn-and-confirm” paradigm in the drug development process and are essential to delivering high-value PK/PD M&S results. Selected works of PK/PD modeling and simulation from preclinical to phase III are presented as case examples in this article.

A Randomized, Controlled Study of Once-Daily LY2605541, a Novel Long-Acting Basal Insulin, Versus Insulin Glargine in Basal Insulin–Treated Patients With Type 2 Diabetes

OBJECTIVE To evaluate whether LY2605541 results in lower fasting blood glucose (FBG) versus insulin glargine (GL). RESEARCH DESIGN AND METHODS This 12-week, randomized, open-label, Phase 2 study enrolled patients with type 2 diabetes (hemoglobin A1c [A1C] ≤ 10.5%), taking metformin and/or sulfonylurea with GL or NPH insulin once daily. Patients converted to morning insulin administration during lead-in were randomized 2:1 from GL (n = 248) or NPH insulin (n = 39) to LY2605541 (n = 195) or GL (n = 95) once daily in the morning. RESULTS At 12 weeks, FBG (mean ± SE) was similar with LY2605541 and GL (118.2 ± 2.0 mg/dL [6.6 ± 0.1 mmol/L] vs. 116.9 ± 2.7 mg/dL [6.5 ± 0.2 mmol/L], P = 0.433) as was A1C (7.0 ± 0.1 vs. 7.2 ± 0.1%, P = 0.279). Intraday blood glucose variability was reduced with LY2605541 (34.4 vs. 39.1 mg/dL [1.9 vs. 2.2 mmol/L], P = 0.031). LY2605541 patients had weight loss (−0.6 ± 0.2 kg, P = 0.007), whereas GL patients gained weight (0.3 ± 0.2 kg, P = 0.662; treatment difference: −0.8 kg, P = 0.001). The incidence and rate of both total hypoglycemia and nocturnal hypoglycemia were comparable between LY2605541 and GL, although, LY2605541 had a 48% reduction in nocturnal hypoglycemia after adjusting for baseline hypoglycemia (P = 0.021). Adverse events were similar across treatments. Alanine aminotransferase and aspartate aminotransferase remained within normal range but were significantly higher with LY2605541 (P ≤ 0.001). CONCLUSIONS In patients with type 2 diabetes, LY2605541 and GL had comparable glucose control and total hypoglycemia rates, but LY2605541 showed reduced intraday variability, lower nocturnal hypoglycemia, and weight loss relative to GL.

Model-based drug development : The road to quantitative pharmacology

High development costs and low success rates in bringing new medicines to the market demand more efficient and effective approaches. Identified by the FDA as a valuable prognostic tool for fulfilling such a demand, model-based drug development is a mathematical and statistical approach that constructs, validates, and utilizes disease models, drug exposure-response models, and pharmacometric models to facilitate drug development. Quantitative pharmacology is a discipline that learns and confirms the key characteristics of new molecular entities in a quantitative manner, with goal of providing explicit, reproducible, and predictive evidence for optimizing drug development plans and enabling critical decision making. Model-based drug development serves as an integral part of quantitative pharmacology. This work reviews the general concept, basic elements, and evolving role of model-based drug development in quantitative pharmacology. Two case studies are presented to illustrate how the model-based drug development approach can facilitate knowledge management and decision making during drug development. The case studies also highlight the organizational learning that comes through implementation of quantitative pharmacology as a discipline. Finally, the prospects of quantitative pharmacology as an emerging discipline are discussed. Advances in this discipline will require continued collaboration between academia, industry and regulatory agencies.

Better Glycemic Control and Weight Loss With the Novel Long-Acting Basal Insulin LY2605541 Compared With Insulin Glargine in Type 1 Diabetes: A randomized, crossover study

OBJECTIVE To compare effects of LY2605541 versus insulin glargine on daily mean blood glucose as part of a basal-bolus regimen for type 1 diabetes. RESEARCH DESIGN AND METHODS In this randomized, Phase 2, open-label, 2 × 2 crossover study, 137 patients received once-daily basal insulin (LY2605541 or glargine) plus mealtime insulin for 8 weeks, followed by crossover treatment for 8 weeks. Daily mean blood glucose was obtained from 8-point self-monitored blood glucose profiles. The noninferiority margin was 10.8 mg/dL. RESULTS LY2605541 met noninferiority and superiority criteria compared with insulin glargine in daily mean blood glucose (144.2 vs. 151.7 mg/dL, least squares mean difference = −9.9 mg/dL [90% CI −14.6 to −5.2], P < 0.001). Fasting blood glucose variability and A1C were reduced with LY2605541 compared with insulin glargine (both P < 0.001). Mealtime insulin dose decreased with LY2605541 and increased with insulin glargine. Mean weight decreased 1.2 kg with LY2605541 and increased 0.7 kg with insulin glargine (P < 0.001). The total hypoglycemia rate was higher for LY2605541 (P = 0.04) and the nocturnal hypoglycemia rate was lower (P = 0.01), compared with insulin glargine. Adverse events (including severe hypoglycemia) were similar, although more gastrointestinal-related events occurred with LY2605541 (15% vs. 4%, P < 0.001). Mean changes (all within normal range) were higher for alanine aminotransferase, aspartate aminotransferase, triglycerides, and LDL-cholesterol and lower for HDL-cholesterol with LY2605541 compared with insulin glargine (all P < 0.02). CONCLUSIONS In type 1 diabetes, compared with insulin glargine, LY2605541, a novel, long-acting basal insulin, demonstrated greater improvements in glycemic control, increased total hypoglycemia, and reduced nocturnal hypoglycemia, as well as reduced weight and lowered mealtime insulin doses.

Application of Physiologically Based Pharmacokinetic (PBPK) Modeling to Support Dose Selection: Report of an FDA Public Workshop on PBPK

The US Food and Drug Administration (FDA) public workshop, entitled “Application of Physiologically‐based Pharmacokinetic (PBPK) Modeling to Support Dose Selection focused on the role of PBPK in drug development and regulation. Representatives from industry, academia, and regulatory agencies discussed the issues within plenary and panel discussions. This report summarizes the discussions and provides current perspectives on the application of PBPK in different areas, including its utility, predictive performance, and reporting for regulatory submissions.

Novel PEGylated Basal Insulin LY2605541 Has a Preferential Hepatic Effect on Glucose Metabolism

The impact of the novel basal insulin LY2605541 (LY) on hepatic and nonhepatic glucose uptake (non-HGU) was evaluated. Conscious dogs underwent euglycemic clamps with tracer and hepatic balance measurements. Clamp period infusions were peripheral venous regular insulin (0.1 nmol ⋅ kg−1 ⋅ h−1 [control], n = 6) or LY (bolus [nmol/kg], continuous [nmol ⋅ kg−1 ⋅ h−1]: 0.5, 0.5 [n = 6]; 0.375, 0.375 [n = 5]; 0.25, 0.25 [n = 4]), somatostatin, and glucose, as well as intraportal glucagon (basal). During the clamp, the dogs switched from net hepatic glucose output to uptake (rates reached 2.1 ± 1.2, 0.9 ± 2.1, 8.6 ± 2.3, and 6.0 ± 1.1 µmol ⋅ kg−1 ⋅ min−1 within 5 h in control, LY0.25, LY0.375, and LY0.5, respectively). Non-HGU in LY increased less than in control; the ratio of change from basal in non-HGU to change in net hepatic glucose balance, calculated when glucose infusion rates (GIRs) were ~20 µmol ⋅ kg-1 ⋅ min−1 in all groups, was higher in control (1.17 ± 0.38) versus LY0.25 (0.39 ± 0.33), LY0.375 (−0.01 ± 0.13), and LY0.5 (−0.09 ± 0.07). Likewise, the change from baseline in glucose Rd-to-Ra ratio was greatest in control (1.4 ± 0.3 vs. 0.6 ± 0.4, 0.5 ± 0.2, and 0.6 ± 0.2 in LY0.25, LY0.375, and LY0.5, respectively). In contrast to exogenously administered human insulin, LY demonstrated preferential hepatic effects, similar to endogenously secreted insulin. Therefore, the analog might reduce complications associated with current insulin therapy.

Steady-state pharmacokinetics and glucodynamics of the novel, long-acting basal insulin LY2605541 dosed once-daily in patients with type 2 diabetes mellitus.

To assess the pharmacokinetics (PK) and glucodynamics (GD) of LY2605541 in patients with type 2 diabetes mellitus.

Basal Insulin Peglispro Demonstrates Preferential Hepatic Versus Peripheral Action Relative to Insulin Glargine in Healthy Subjects

OBJECTIVE We evaluated the endogenous glucose production (EGP) and glucose disposal rate (GDR) over a range of doses of basal insulin peglispro (BIL) and insulin glargine in healthy subjects. RESEARCH DESIGN AND METHODS This was a single-center, randomized, open-label, four-period, incomplete-block, crossover study conducted in eight healthy male subjects. Subjects had 8-h euglycemic clamps performed with primed, continuous infusions of BIL (5.1 to 74.1 mU/min) in three dosing periods and insulin glargine (20 or 30 mU/m2/min) in a fourth period, targeted to achieve 50–100% suppression of EGP. D-[3-3H] glucose was infused to assess rates of glucose appearance and disappearance. RESULTS Mean BIL and insulin glargine concentrations (targeted to reflect the differences in intrinsic affinities of the two basal insulins) ranged from 824 to 11,400 and 212 to 290 pmol/L, respectively, and increased accordingly with increases in dose. Suppression of EGP and stimulation of GDR were observed with increasing concentrations of both insulins. At insulin concentrations where EGP was significantly suppressed, insulin glargine resulted in increased GDR. In contrast, at comparable suppression of EGP, BIL had minimal effect on GDR at lower doses and had substantially less effect on GDR than insulin glargine at higher doses. CONCLUSIONS The novel basal insulin analog BIL has relative hepatopreferential action and decreased peripheral action, compared with insulin glargine, in healthy subjects.

PBPK Model Describes the Effects of Comedication and Genetic Polymorphism on Systemic Exposure of Drugs That Undergo Multiple Clearance Pathways

An important goal in drug development is to understand the effects of intrinsic and/or extrinsic factors (IEFs) on drug pharmacokinetics. Although clinical studies investigating a given IEF can accomplish this goal, they may not be feasible for all IEFs or for situations when multiple IEFs exist concurrently. Physiologically based pharmacokinetic (PBPK) models may serve as a complementary tool for forecasting the effects of IEFs. We developed PBPK models for four drugs that are eliminated by both cytochrome P450 (CYP)3A4 and CYP2D6, and evaluated model prediction of the effects of comedications and/or genetic polymorphism on drug exposure. PBPK models predicted 100 and ≥70% of the observed results when the conventional “twofold rule” and the more conservative 25% deviation cut point were applied, respectively. These findings suggest that PBPK models can be used to infer effects of individual or combined IEFs and should be considered to optimize studies that evaluate these factors, specifically drug interactions and genetic polymorphism of drug‐metabolizing enzymes.

Single-dose pharmacokinetics and glucodynamics of the novel, long-acting basal insulin LY2605541 in healthy subjects.

LY2605541 is a novel basal insulin analog with a prolonged duration of action. Two Phase I studies assessed LY2605541 pharmacokinetics (PK), glucodynamics (GD), and tolerability in healthy subjects. In Study 1, 33 subjects received single subcutaneous (SC) doses of LY2605541 (0.01–2.22 U/kg) and insulin glargine (0.5–0.8 U/kg) followed by euglycemic clamp for up to 24–36 hours. In Study 2, absolute bioavailability of SC LY2605541 was assessed in 8 subjects by comparing dose normalized area under concentration versus time curve of SC against IV administration. Time‐to‐maximum plasma concentration (medians) and geometric means for half‐life (t1/2) and apparent clearance, respectively, ranged from 18.0 to 42.0 hours, 24.4–45.5 hours, and 1.8–2.8 L/h for SC LY2605541, versus 10.0–12.0 hours, 12.2–14.9 hours, and 51.4–65.2 L/h for SC insulin glargine. LY2605541 glucose infusion rate (GIR) profiles were sustained for ≥36 hours versus glargine GIR profiles, which waned at 24 hours. After IV administration, LY2605541s geometric mean t1/2 was 2.3 hours. LY2605541 intra‐subject variability (CV%) was <18% for PK and <32% for GD parameters. The most common adverse events were related to study procedures and were mild‐moderate in severity. These results established a well‐tolerated baseline dose for LY2605541 with a relatively flat PK profile and low intra‐subject variability.