Abstract Details

Title Pharmacokinetics of Intravenous Immunoglobulin in Multifocal Motor Neuropathy

Topic Peripheral Nerve

Presentation(s) P01 - (-)

Poster/Presentation
Number 152

Objective

Background BACKGROUND: MMN can successfully be treated with IVIg. Maintenance therapy is often required, but the optimal dose and treatment intervals for IVIg infusions have not been established. Changes in IgG concentrations (?IgG) after IVIg infusion show large variability between patients, which may suggest differences in expression of the endothelial IgG Fc receptor (FcRn) that protects IgG against catabolism. ?IgG may represent a potentially useful biomarker to tailor IVIg therapy in individual patients.

Design/Methods DESIGN/METHODS: Twenty-three patients with MMN were included. Patients were treated with a cumulative IVIg dose of 2.0 g/kg in 5 days and treatment response was monitored. A positive treatment response was defined as an increase in muscle strength in at least two muscle groups of 1 grade or more on the MRC scale. IgG concentrations in serum were determined at baseline, at days 1 and 5 of the IVIg course and 3 weeks after treatment. FcRn copy number variation and differences in repeat length of the variable number of tandem repeats (VNTR) in the FcRn gene were also determined.

Results RESULTS: Seventeen patients (74%) responded to treatment. Total IgG levels and increase of IgG levels compared to baseline (?IgG) varied substantially between patients. Median ?IgG levels were higher in IVIg responders than in non-responders, with the largest difference on day 1 (8.6 vs. 2.3 g/L, p-value = 0.16). Genetic variation in the FcRn gene was not associated with ?IgG levels or response to treatment.

Conclusions CONCLUSIONS: IVIg pharmacokinetics varies in patients with MMN and may be associated with clinical response, but can not be explained by genetic heterogeneity or copy number variation of FcRn.

Authors/Disclosures
PRESENTER	No disclosure on file
Elisabeth A. Cats, MD	No disclosure on file
	No disclosure on file
Jan H. Veldink, MD, PhD	The institution of Dr. Veldink has received research support from Biogen.
Leonard van den Berg, MD (University Medical Centre Utrecht)	The institution of Dr. Van den Berg has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Amylyx. The institution of Dr. Van den Berg has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for ferrrer. The institution of Dr. Van den Berg has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sanofi. The institution of Dr. Van den Berg has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biogen. The institution of Dr. Van den Berg has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Takeda. The institution of Dr. Van den Berg has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis. The institution of Dr. Van den Berg has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for BMS. The institution of Dr. Van den Berg has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for ArgenX. The institution of Dr. Van den Berg has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Projenx. Dr. Van den Berg has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Corcept. The institution of Dr. Van den Berg has received research support from Netherlands ALS Foundation.
	No disclosure on file
James Brewer, MD, PhD (UC San Diego)	No disclosure on file

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