Population Pharmacokinetics of Vixotrigine in Healthy Volunteers and Subjects with Trigeminal Neuralgia, Painful Lumbosacral Radiculopathy and Erythromelalgia

BACKGROUND

Vixotrigine is a voltage and use dependent sodium channel blocker currently under development for treatment of various neuropathic pain indications.

OBJECTIVE

The objective of this work was to develop a population pharmacokinetic model and assess effects of various covariates on pharmacokinetic parameters of vixotrigine.

METHOD

Plasma concentration-time data from 12 Phase 1 or 2 studies were included in the analyses. The data were obtained following administration of single or multiple doses of vixotrigine in healthy volunteers and patients. One- and two-compartment pharmacokinetic models were evaluated as base structural pharmacokinetic models. The inclusion of selected covariates was assessed using a stepwise backward elimination approach (α = 0.001) once the base/full model was developed. The predictive ability of the model was evaluated using a visual predictive check (VPC). The final model was used to evaluate effect of covariates on exposure of vixotrigine.

RESULTS

A total of 10,263 pharmacokinetic samples collected from 465 subjects were included in the analyses. The pharmacokinetics of vixotrigine was adequately described by a two-compartment model with two transit absorption compartments and first-order elimination. Predictability of the model was also established by VPC. The final model included covariates of age, weight and carbamazepine co-administration on clearance, weight on central volume of distribution, food on absorption rate constant and formulation and Japanese race on bioavailability. None of the covariates identified had a clinically relevant effect, as impact on area under the plasma concentration-time curve (AUC) and maximum plasma concentration (C_max) was within ± 25%.

CONCLUSION

The model characterizes the pharmacokinetics of vixotrigine well, and the exposure of vixotrigine was comparable between healthy subjects and patients. None of the covariates evaluated have a clinically relevant impact on the pharmacokinetics of vixotrigine.

Efficacy and safety of a premixed versus a basal-plus insulin regimen as intensification for type 2 diabetes by timing of the main meal

OBJECTIVE

To describe the efficacy and safety of premixed insulin lispro protamine suspension 75%/insulin lispro solution 25% (LM25) twice daily (bid) versus basal insulin glargine plus prandial insulin lispro (IGL), both once daily, according to main meal timing.

METHODS

Data were obtained post hoc from a 24 week, randomized, open-label study comparing LM25 and IGL as insulin intensification in patients with type 2 diabetes inadequately controlled with once daily basal insulin glargine plus metformin and/or pioglitazone (ClinicalTrials.gov identifier: NCT01175824). Patients administered LM25 bid before breakfast and the evening meal, insulin glargine at bedtime and insulin lispro before the day's main meal (meal with the highest 2 hour postprandial glucose level during screening). Patients were grouped by main meal. Changes in glycosylated hemoglobin (HbA1c) and bodyweight were summarized using likelihood-based mixed models; hypoglycemia incidence was compared between treatments using Fisher's exact test.

RESULTS

Overall, 476 patients (LM25, n = 236; IGL, n = 240) were randomized. In all main meal groups, with both insulin regimens, mean HbA1c significantly decreased from baseline to 24 weeks (p < 0.0001). Patients whose main meal was in the evening had a greater bodyweight increase with LM25 than with IGL (p = 0.015), and a smaller proportion of these patients experienced total (p = 0.027) and nocturnal (p = 0.006) hypoglycemia with LM25 compared with IGL. Patients whose main meal was lunch experienced more nocturnal hypoglycemia with LM25 than with IGL (p = 0.030). Study limitations include that this was a post hoc analysis and no assessments ensured that: SMBG results determined timing of the main meal, each patient's main meal remained unchanged throughout the study, or patients administered insulin lispro with that meal.

CONCLUSIONS

Glycemic control improved in patients receiving either LM25 or IGL, irrespective of main meal timing. Both regimens can be used in patients with inadequate glycemic control who are in need of insulin intensification.

Insulin lispro low mixture twice daily versus basal insulin glargine once daily and prandial insulin lispro once daily in patients with type 2 diabetes requiring insulin intensification: a randomized phase IV trial

AIMS

To compare the efficacy and safety of two insulin intensification strategies in patients with type 2 diabetes inadequately controlled on basal insulin glargine with metformin and/or pioglitazone.

METHODS

A multinational, randomized, open-label trial that compared insulin lispro low mixture (LM25; n = 236) twice daily with a basal-prandial regimen of insulin glargine once daily and insulin lispro once daily (IGL; n = 240) over 24 weeks in patients with HbA1c 7.5-10.5% and fasting plasma glucose ≤ 6.7 mmol/l. The primary objective was to assess non-inferiority [per-protocol (PP) population], and then superiority [intention-to-treat (ITT) population], of LM25 versus IGL according to change in HbA1c after 24 weeks (non-inferiority margin 0.4%, two-sided significance level 0.05).

RESULTS

Estimated change [least squares (LS) mean (95% CI)] in HbA1c after 24 weeks: -1.30 (-1.44, -1.16)% with LM25 and -1.08 (-1.22, -0.94)% with IGL. Non-inferiority was shown [LS mean (95% CI) HbA1c treatment difference -0.21 (-0.38, -0.04) (PP population)]; gated superiority assessment showed a statistically significant advantage for LM25 (p = 0.010; ITT population). Mean blood glucose, glycaemic variability, overall tolerability and hypoglycaemic episodes per patient-year did not show significant differences between treatments during the study.

CONCLUSIONS

In patients with type 2 diabetes inadequately controlled on once-daily basal insulin glargine and metformin and/or pioglitazone, intensification with LM25 was superior to a basal-prandial approach in terms of reduction in HbA1c after 24 weeks and did not increase hypoglycaemia episodes.

Glucagon-like peptide 1 receptor agonist or bolus insulin with optimized basal insulin in type 2 diabetes

OBJECTIVE

Mealtime insulin is commonly added to manage hyperglycemia in type 2 diabetes when basal insulin is insufficient. However, this complex regimen is associated with weight gain and hypoglycemia. This study compared the efficacy and safety of exenatide twice daily or mealtime insulin lispro in patients inadequately controlled by insulin glargine and metformin despite up-titration.

RESEARCH DESIGN AND METHODS

In this 30-week, open-label, multicenter, randomized, noninferiority trial with 12 weeks prior insulin optimization, 627 patients with insufficient postoptimization glycated hemoglobin A1c (HbA1c) were randomized to exenatide (10-20 µg/day) or thrice-daily mealtime lispro titrated to premeal glucose of 5.6-6.0 mmol/L, both added to insulin glargine (mean 61 units/day at randomization) and metformin (mean 2,000 mg/day).

RESULTS

Randomization HbA1c and fasting glucose (FG) were 8.3% (67 mmol/mol) and 7.1 mmol/L for exenatide and 8.2% (66 mmol/mol) and 7.1 mmol/L for lispro. At 30 weeks postrandomization, mean HbA1c changes were noninferior for exenatide compared with lispro (-1.13 and -1.10%, respectively); treatment differences were -0.04 (95% CI -0.18, 0.11) in per-protocol (n = 510) and -0.03 (95% CI -0.16, 0.11) in intent-to-treat (n = 627) populations. FG was lower with exenatide than lispro (6.5 vs. 7.2 mmol/L; P = 0.002). Weight decreased with exenatide and increased with lispro (-2.5 vs. +2.1 kg; P < 0.001). More patients reported treatment satisfaction and better quality of life with exenatide than lispro, although a larger proportion of patients with exenatide experienced treatment-emergent adverse events. Exenatide resulted in fewer nonnocturnal hypoglycemic episodes but more gastrointestinal adverse events than lispro.

CONCLUSIONS

Adding exenatide to titrated glargine with metformin resulted in similar glycemic control as adding lispro and was well tolerated. These findings support exenatide as a noninsulin addition for patients failing basal insulin.

Resource utilisation and clinical data before and after switching between short-acting human insulin and rapid-acting insulin analogues in patients with type 2 diabetes: the SWING study

AIM

SWING was a prospective, observational study conducted in nine European countries primarily to assess direct treatment costs when switching from short-acting human insulins to rapid-acting insulin analogues (H-A) or vice versa (A-H) in patients with type 2 diabetes.

METHODS

Data were collected at a baseline visit (time of switch) and at approximately 3, 6 and 12 months post-switch.

RESULTS

In total, 2389 patients switched from H-A (n=2203) or A-H (n=186); another 603 were enrolled but ineligible. Mean (SD) direct diabetes-related costs (pro-rated to account for variable visit schedules) were €548.7 (865.8) 6 months prior to switch, €625.6 (1474.9) at 0-6 months and €568.6 (590.7) 6-12 months following switch for H-A, and €544.5 (421.0), €481.0 (301.5) and €461.6 (335.0) for A-H, respectively. Mean (SD) HbA(1c) decreased over 12 months by 1.08 (1.53)% units H-A and 1.17 (1.45)% units A-H. A small decline in hypoglycaemia occurred over time, but there were no clinically meaningful changes in mean PROs.

CONCLUSIONS

There were small changes in mean direct diabetes-related costs (following adjustment for time interval) in patients switching in either direction. Improvements in mean HbA(1c) and incidence of hypoglycaemia cannot necessarily be attributed to therapeutic switch.

Comparison of insulin lispro protamine suspension versus insulin glargine once daily in basal-bolus therapies with insulin lispro in type 2 diabetes patients: a prospective randomized open-label trial

AIMS

To compare the efficacy and safety of insulin lispro protamine suspension (ILPS) versus insulin glargine once daily in a basal-bolus regimen in type 2 diabetes mellitus (T2DM) patients.

METHODS

Three hundred eighty-three insulin-treated patients were randomized to either ILPS plus lispro or glargine plus lispro in this open-label 24-week European study. Insulin doses were titrated to predefined blood glucose (BG) targets. Non-inferiority of ILPS versus glargine was assessed by comparing the upper limit of the 95% confidence interval (CI) for the change of HbA1c from baseline to week 24 (adjusted for country and baseline HbA1c) with the non-inferiority margin of 0.4%. Secondary endpoints included HbA1c categories, BG profiles, insulin doses, hypoglycaemic episodes, adverse events and vital signs.

RESULTS

Non-inferiority of ILPS versus glargine in the change of HbA1c from baseline was shown: least-square mean between-treatment difference (95% CI) was 0.1% (-0.11; 0.31). Mean changes at week 24 were -1.05% (ILPS) and -1.20% (glargine). HbA1c <7.0% was achieved by 21.7 versus 29.4% of patients. Mean basal/mealtime insulin doses at week 24 were 29.6/36.2 IU/day (ILPS) versus 32.8/42.2 IU/day (glargine); the difference was not statistically significant for total dose (p = 0.7). In both groups, 56.1/25.7% versus 63.6/19.3% of patients experienced any/nocturnal hypoglycaemia (p = 0.2 for both). No relevant differences were noted in any other variables.

CONCLUSIONS

A basal-bolus regimen with ILPS once daily resulted in non-inferior glycaemic control compared to a similar regimen with glargine, without statistically significant or clinically relevant differences in hypoglycaemia. ILPS-based regimens can be considered an alternative to basal-bolus regimens with glargine for T2DM patients.