Dataset Information

Ravulizumab pharmacokinetics and pharmacodynamics in patients with generalized myasthenia gravis.

ABSTRACT:

Introduction

The terminal complement C5 inhibitor ravulizumab has a long elimination half-life, allowing maintenance dosing every 8 weeks. In the 26-week, double-blind, randomized, placebo-controlled period (RCP) of the CHAMPION MG study, ravulizumab provided rapid and sustained efficacy and was well tolerated in adults with anti-acetylcholine receptor antibody-positive (AChR Ab+) generalized myasthenia gravis (gMG). This analysis evaluated the pharmacokinetics (PK), pharmacodynamics (PD), and potential immunogenicity of ravulizumab in adults with AChR Ab+ gMG.

Methods

Data were analyzed from 86 patients who received ravulizumab in the CHAMPION MG RCP. Ravulizumab dosing was weight-based: initial loading dose of 2400/2700/3000 mg on Day 1 and maintenance doses of 3000/3300/3600 mg on Day 15 and then every 8 weeks. PK parameters were estimated from serum ravulizumab concentrations determined pre- and post-dose; PD effects of ravulizumab on serum free C5 concentrations were measured; and immunogenicity was assessed using anti-drug antibody and neutralizing-antibody assays.

Results

Target serum ravulizumab concentrations (> 175 µg/mL) were achieved immediately after the first ravulizumab dose (within 30 min of infusion completion) and maintained throughout the 26-week treatment period irrespective of patient body weight. Following the final maintenance dose, mean C_max was 1548 µg/mL and C_trough 587 µg/mL; no meaningful differences were noted among body-weight categories. Inhibition of serum free C5 was immediate, complete (< 0.5 μg/mL), and sustained throughout treatment in all patients. No treatment-emergent anti-drug antibodies were observed.

Conclusions

PK/PD evidence supports the use of ravulizumab every 8 weeks for immediate, complete, and sustained inhibition of terminal complement C5 in adults with AChR Ab+ gMG.

Trial registration

ClinicalTrials.gov ID: NCT03920293 (April 18, 2019).

SUBMITTER: Vu T

PROVIDER: S-EPMC10188401 | biostudies-literature | 2023 Jun

REPOSITORIES: biostudies-literature

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Publications

Ravulizumab pharmacokinetics and pharmacodynamics in patients with generalized myasthenia gravis.

Vu Tuan T Ortiz Stephan S Katsuno Masahisa M Annane Djillali D Mantegazza Renato R Beasley Kathleen N KN Aguzzi Rasha R Howard James F JF

Journal of neurology 20230309 6

<h4>Introduction</h4>The terminal complement C5 inhibitor ravulizumab has a long elimination half-life, allowing maintenance dosing every 8 weeks. In the 26-week, double-blind, randomized, placebo-controlled period (RCP) of the CHAMPION MG study, ravulizumab provided rapid and sustained efficacy and was well tolerated in adults with anti-acetylcholine receptor antibody-positive (AChR Ab+) generalized myasthenia gravis (gMG). This analysis evaluated the pharmacokinetics (PK), pharmacodynamics (PD ...[more]

PMID: 36890354

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Project description:Objective: To investigate the pharmacokinetics, pharmacodynamics, and exposure-response of the approved 900/1,200 mg dosing regimen for the terminal complement component 5 (C5) inhibitor eculizumab in patients with generalized myasthenia gravis (gMG). Methods: The analysis used data from 62 patients aged ≥ 18 years with anti-acetylcholine receptor (AChR) antibody-positive refractory gMG who received eculizumab during the REGAIN study (ClinicalTrials.gov: NCT01997229). One- and two-compartment population-pharmacokinetic models were evaluated, and the impact of covariates on pharmacokinetic parameters was assessed. Relationships between eculizumab exposure and free C5 concentration, in vitro hemolytic activity, clinical response, and tolerability were characterized. Results: Steady-state serum eculizumab concentrations were achieved by Week 4 and were sustained throughout the 26-week treatment period. The eculizumab pharmacokinetic data were well-described by a two-compartment model with first-order elimination, including effects of body weight on pharmacokinetic parameters and plasma-exchange events on clearance. Complete inhibition of terminal complement was achieved in nearly all patients at the time of trough and peak eculizumab concentrations at all post-dose timepoints assessed (free C5 < 0.5 μg/ml in 92% of patients; in vitro hemolysis < 20% in 87% of patients). Serum eculizumab concentrations of ≥116 μg/ml achieved free C5 concentrations of < 0.5 μg/ml. Clinical efficacy and tolerability were consistent across the eculizumab exposure range. Conclusions: Rigorous, quantitative, model-based exposure-response analysis of serum eculizumab concentration and response data demonstrated that the approved eculizumab dosing (900/1,200 mg) for adults with anti-AChR antibody-positive refractory gMG rapidly achieved complete inhibition of terminal complement activation and provided sustained clinical efficacy across the eculizumab exposure range.

Project description:ImportanceUse of biologic agents in generalized myasthenia gravis is generally limited to therapy-refractory cases; benefit in new-onset disease is unknown.ObjectiveTo assess rituximab in refractory and new-onset generalized myasthenia gravis and rituximab vs conventional immunotherapy in new-onset disease.Design, setting, and participantsA retrospective cohort study with prospectively collected data was conducted on a county-based community sample at Karolinska University Hospital, Stockholm, Sweden. Participants included 72 patients with myasthenia gravis, excluding those displaying muscle-specific tyrosine kinase antibodies, initiating rituximab treatment from January 1, 2010, to December 31, 2018, and patients with new-onset disease initiating conventional immunotherapy from January 1, 2003, to December 31, 2012, with 12 months or more of observation time. The present study was conducted from March 1, 2019, to January 31, 2020.ExposuresTreatment with low-dose rituximab (most often 500 mg every 6 months) or conventional immunosuppressants.Main outcomes and measuresTime to remission (main outcome) as well as use of rescue therapies or additional immunotherapies and time in remission (secondary outcomes).ResultsOf the 72 patients included, 31 patients (43%) were women; mean (SD) age at treatment start was 60 (18) years. Twenty-four patients had received rituximab within 12 months of disease onset and 48 received rituximab at a later time, 34 of whom had therapy-refractory disease. A total of 26 patients (3 [12%] women; mean [SD] age, 68 [11] years at treatment start) received conventional immunosuppressant therapy. Median time to remission was shorter for new-onset vs refractory disease (7 vs 16 months: hazard ratio [HR], 2.53; 95% CI, 1.26-5.07; P = .009 after adjustment for age, sex, and disease severity) and for rituximab vs conventional immunosuppressant therapies (7 vs 11 months: HR, 2.97; 95% CI, 1.43-6.18; P = .004 after adjustment). In addition, fewer rescue therapy episodes during the first 24 months were required (mean [SD], 0.38 [1.10] vs 1.31 [1.59] times; mean difference, -1.26; 95% CI, -1.97 to -0.56; P < .001 after adjustment), and a larger proportion of patients had minimal or no need of additional immunotherapies (70% vs 35%; OR, 5.47; 95% CI, 1.40-21.43; P = .02 after adjustment). Rates of treatment discontinuation due to adverse events were lower with rituximab compared with conventional therapies (3% vs 46%; P < .001 after adjustment).Conclusions and relevanceClinical outcomes with rituximab appeared to be more favorable in new-onset generalized myasthenia gravis, and rituximab also appeared to perform better than conventional immunosuppressant therapy. These findings suggest a relatively greater benefit of rituximab earlier in the disease course. A placebo-controlled randomized trial to corroborate these findings is warranted.

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Dataset Information

Ravulizumab pharmacokinetics and pharmacodynamics in patients with generalized myasthenia gravis.

Introduction

Methods

Results

Conclusions

Trial registration

Publications

Ravulizumab pharmacokinetics and pharmacodynamics in patients with generalized myasthenia gravis.

Similar Datasets

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