1318. Pharmacokinetics and Safety of Cefepime-Taniborbactam (formerly Cefepime/VNRX-5133) in Subjects with Renal Impairment

Background

Taniborbactam is a novel, non-ß-lactam, ß-lactamase inhibitor with activity against serine (Class A, C, D) and metallo (Class B) ß-lactamases including epidemiologically important carbapenemases. Both cefepime and taniborbactam are predominantly renally excreted and are likely to require dose adjustment in patients with renal impairment and end-stage renal disease (ESRD). The current study was designed to evaluate the pharmacokinetics and safety in patients with renal impairment and ESRD.

Methods

This was a Phase 1, open-label study in subjects with normal renal function (eCL_CR ≥ 90 mL/min) matched to subjects with mild, moderate, and severe renal impairment (eGFR 60-89, 30-59, and < 30 mL/min/1.73m², respectively), and patients with ESRD on hemodialysis. Subjects received a single dose of cefepime 2 g and taniborbactam 500 mg; subjects with ESRD received a single dose before HD and after a 9 day washout period, following HD. PK parameters including AUC_0-inf and total body clearance (CL) were evaluated. Safety assessments included adverse events (AEs), vital signs, clinical laboratory evaluations, electrocardiograms, and physical examinations.

Results

Thirty-three subjects were enrolled; 67% male, 58% white and 39% black/African Americans. Median age and BMI were 55.0 years and 29.5 kg/m², respectively. For both cefepime and taniborbactam, exposures increased, and CL decreased with increasing renal impairment (see Table). The hemodialysis extraction ratio was 49.7% and 47.4% for taniborbactam and cefepime respectively. No safety signals were observed and there were no serious adverse events.

Table

Conclusion

Cefepime and taniborbactam CL is similarly reduced with varying degrees of renal impairment. Dialysis removes a high fraction of both drugs. Dose adjustments recommended for cefepime are appropriate for taniborbactam.

Disclosures

Brooke Geibel, BS, Venatorx Pharmaceuticals (Employee, Shareholder) James A. Dowell, PhD, Venatorx Pharmaceuticals (Independent Contractor) Thomas C. Marbury, MD, Venatorx Pharmaceuticals (Independent Contractor) William Smith, MD, Venatorx Pharmaceuticals (Independent Contractor) Paul C. McGovern, MD, Venatorx Pharmaceuticals (Employee) Cynthia Richards, MD, Venatorx Pharmaceuticals (Independent Contractor) Tim Henkel, MD, PhD, Venatorx Pharmaceuticals (Employee, Shareholder)

1401. A Randomized, Double-Blind, Placebo-Controlled Study of the Safety and Pharmacokinetics of Single and Repeat Doses of VNRX-5133 in Healthy Subjects

Background

VNRX-5133 is a novel, non-β-lactam, β-lactamase inhibitor with potent and selective direct inhibitory activity against serine- and metallo-β-lactamases. VNRX-5133, combined with the β-lactam antibiotic cefepime, is being developed for the treatment of serious infections due to multidrug-resistant Gram-negative bacteria, including ESBL-producing organisms and carbapenem-resistant Enterobacteriaceae and Pseudomonas aeruginosa. This study evaluated the safety and pharmacokinetics (PK) of VNRX-5133 after single and multiple intravenous (IV) doses.

Methods

This was a Phase 1, randomized, single-center, double-blind, placebo-controlled, sequential group study in healthy subjects. In a single ascending dose (SAD), phase subjects received 62.5, 125, 250, 500, 1000, and 1500 mg VNRX-5133 via a 2-hour IV infusion. In a multiple ascending dose (MAD) phase, subjects received 250, 500, and 750 mg VNRX-5133 q8h for 10 days. PK samples were collected predose and at frequent intervals. Safety was assessed from adverse events (AEs), laboratory tests, physical examination, vital signs, and electrocardiogram (ECG).

Results

All subjects completed the SAD (n = 48) and the MAD phases (n = 36). VNRX-5133 plasma exposure exhibited dose proportionality and linearity. Total clearance (CL) was ~6 L/h and volume of distribution (Vz) was ~30 to 50 L. The t_1/2 based on a noncompartmental analysis was ~6.5 hours. Modeling of VNRX-5133 plasma concentrations showed that the PK fit a 2-compartment model with most of the drug exposure accounted for within the initial phase of ~2 hours. Minimal accumulation of VNRX-5133 was observed following q8h dosing over 10 days. In the SAD phase, AEs occurred in four subjects (33.3%) with placebo and seven (19.4%) with VNRX-5133. In the MAD phase, AEs occurred in three subjects (33.3%) with placebo and eight (29.6%) with VNRX-5133. The most common AEs with VNRX-5133 were headache (11.1%), nausea (7.4%), and constipation (7.4%).

Conclusion

After single doses of 62.5–1,500 mg and multiple doses of 250–750 mg q8h, VNRX-5133 demonstrated a linear and dose-proportional PK profile with low variability. No safety issues were identified.

Disclosures

B. Geibel, VenatoRx Pharmaceuticals, Inc.: Employee, Salary. J. Dowell, VenatoRx Pharmaceuticals, Inc.: Consultant, Consulting fee. D. Dickerson, VenatoRx Pharmaceuticals, Inc.: Research Contractor, Research support. T. Henkel, VenatoRx Pharmaceuticals, Inc.: Employee, Salary

A randomized, double-blind, placebo-controlled, dose-ranging study of lisdexamfetamine dimesylate augmentation for major depressive disorder in adults with inadequate response to antidepressant therapy

BACKGROUND

This randomized, double-blind, placebo-controlled study evaluated dose-response relationships of lisdexamfetamine dimesylate when used as augmentation for major depressive disorder in individuals exhibiting inadequate responses to antidepressant monotherapy.

METHODS

Eligible adults (18-65 years) were assigned to antidepressant monotherapy (escitalopram or venlafaxine extended-release) plus lisdexamfetamine dimesylate-matching placebo during an eight-week single-blind lead-in phase. Participants meeting randomization criteria were randomized (1:1:1:1:1) to eight weeks of lisdexamfetamine dimesylate (10, 30, 50, or 70 mg) or placebo while maintaining antidepressant therapy. Dose-responses for changes from augmentation baseline to week 16/early termination for Montgomery-Åsberg Depression Rating Scale total score (primary efficacy endpoint) and vital signs (systolic and diastolic blood pressure and pulse) were assessed using multiple comparisons procedures with modeling.

RESULTS

For Montgomery-Åsberg Depression Rating Scale total score change, no significant dose-responses were observed for any candidate dose-response curve (all p>0.10). In the dose-response evaluable population, least squares mean (90% confidence interval) treatment differences versus placebo for Montgomery-Åsberg Depression Rating Scale total score change at week 16 were -1.4 (-3.9, 1.2), 0.1 (-2.5, 2.7), -0.7 (-3.4, 2.0), and -0.9 (-3.5, 1.6) with 10, 30, 50, and 70 mg lisdexamfetamine dimesylate, respectively. For all vital sign parameters, lisdexamfetamine dimesylate exhibited significant dose-responses for all candidate dose-response curves (all p<0.10), with increases observed as lisdexamfetamine dimesylate dose increased; a linear relationship provided the best fit. Mean±standard deviation changes from augmentation baseline for systolic and diastolic blood pressure and pulse at week 16/early termination were -0.7±9.90 and -0.3±7.24 mm Hg and 0.2±10.57 bpm with placebo and were 1.9±9.47 and 0.8±7.40 mm Hg and 3.6±9.74 bpm with lisdexamfetamine dimesylate (all doses combined). The safety and tolerability profile of lisdexamfetamine dimesylate was consistent with previous studies.

CONCLUSIONS

Lisdexamfetamine dimesylate augmentation did not provide benefit over placebo in adults with inadequate responses to antidepressant monotherapy based on the assessed efficacy measures.

Lisdexamfetamine dimesylate augmentation for adults with major depressive disorder and inadequate response to antidepressant monotherapy: Results from 2 phase 3, multicenter, randomized, double-blind, placebo-controlled studies

BACKGROUND

The efficacy, safety, and tolerability of lisdexamfetamine dimesylate (LDX) augmentation of antidepressant monotherapy in adults with major depressive disorder (MDD) from two phase 3 studies are reported.

METHODS

Across study 1 (placebo, n=201; LDX, n=201) and study 2 (placebo, n=213; LDX, n=211), most participants (placebo and LDX) in the safety analysis set were female (study 1: 66.2% and 64.2%; study 2: 67.1% and 66.8%); mean±SD ages were 41.8±12.04 with placebo and 42.2±12.32 with LDX in study 1 and 42.6±11.41 with placebo and 42.0±11.63 with LDX in study 2. Participants (18-65 y) had DSM-IV-TR-diagnosed MDD and lead-in baseline Montgomery-Åsberg Depression Rating Scale (MADRS) total scores ≥24. Eight-week antidepressant lead-in phases prospectively assessed antidepressant response. Then, 8 weeks of randomized (1:1), double-blind treatment with dose-optimized LDX (20-70mg) or placebo in participants exhibiting inadequate antidepressant monotherapy responses (augmentation baseline MADRS total scores ≥18 and <50% MADRS total score reductions from lead-in baseline to augmentation baseline) was initiated. The primary endpoint was MADRS total score change from augmentation baseline to week 16. Safety and tolerability measures included the occurrence of treatment-emergent adverse events (TEAEs).

RESULTS

Least squares mean (95% CI) treatment differences (LDX-placebo) for MADRS total score changes from augmentation baseline to week 16 were not statistically significant in study 1 (0.1 [-1.7, 2.0], P=0.883) or study 2 (-0.5 [-2.3, 1.3], P=0.583). The only TEAE reported by >5% of LDX participants at twice the placebo rate in both studies was dry mouth.

LIMITATIONS

Limitations include the exclusion of participants with psychiatric comorbidities/active medical disorders, the inability to assess specific MDD symptom domains (eg, anhedonia, cognition) or subtypes, the use of telephone-based depression assessments, and the potential influence of placebo response.

CONCLUSION

Contrary to expectations, LDX augmentation was not superior to placebo in reducing depressive symptoms in individuals with MDD exhibiting inadequate responses to antidepressant monotherapy.

Time-course of treatment-emergent adverse events in a long-term safety study of lisdexamfetamine dimesylate in children and adolescents with ADHD

Introduction

The long-term safety and efficacy of lisdexamfetamine dimesylate (LDX) in children and adolescents with attention deficit/hyperactivity disorder (ADHD) was evaluated in a European 2-year, open-label study (SPD489-404).

Objective

To evaluate the time-course of treatment-emergent adverse events (TEAEs) in SPD489-404.

Methods

Participants aged 6–17 years received open-label LDX (30, 50 or 70 mg/day) for 104 weeks (4 weeks dose-optimization; 100 weeks dose-maintenance).

Results

All enrolled participants (n = 314) were included in the safety population and 191 (60.8%) completed the study. TEAEs occurred in 282 (89.8%) participants; most were mild or moderate. TEAEs considered by the investigators as related to LDX were reported by 232 (73.9%) participants with the following reported for ≥ 10% of participants: decreased appetite (49.4%), weight decreased (18.2%), insomnia (13.1%). TEAEs leading to discontinuation and serious TEAEs occurred in 39 (12.4%) and 28 (8.9%) participants, respectively. The median (range) time to first onset and duration, respectively, of TEAEs identified by the sponsor as being of special interest were: insomnia (insomnia, initial insomnia, middle insomnia, terminal insomnia), 17.0 (1–729) and 42.8 (1–739) days; weight decreased, 29.0 (1–677) and 225.0 (26–724) days; decreased appetite, 13.5 (1–653) and 169.0 (1–749) days; headache, 22.0 (1–718) and 2.0 (1–729) days. Reports of insomnia, weight decreased, decreased appetite and headache were highest in the first 4–12 weeks.

Conclusions

TEAEs associated with long-term LDX treatment were characteristic of stimulant medications, with the greatest incidence observed during the first 4–12 weeks.

Disclosure of interest

The authors have not supplied their declaration of competing interest.