{Reference Type}: Letter
{Title}: Subcutaneous administration of natalizumab can lead to lower drug concentrations compared to intravenous administration.
{Author}: Gelissen LMY;Loveless S;Toorop AA;Howlett J;Loeff FC;Rispens T;Killestein J;Tallantyre EC;van Kempen ZLE;
{Journal}: Mult Scler Relat Disord
{Volume}: 90
{Issue}: 0
{Year}: 2024 Jul 30
{Factor}: 4.808
{DOI}: 10.1016/j.msard.2024.105796
{Abstract}: <B>BACKGROUND: </B>Several studies reported lower drug concentrations with subcutaneous natalizumab compared to intravenous natalizumab. With the emergence of extended interval dosing, gaining more insight into lower concentrations after subcutaneous administration is essential.<BR><B>METHODS: </B>We compared serum trough concentrations between subcutaneous and intravenous administration within a matched cohort (n = 50).<BR><B>RESULTS: </B>Subcutaneous administration (n = 25) was associated with lower concentrations compared to intravenous administration (n = 25) (log-B=-0.28, p = 0.01). In an exploratory group of 11 patients receiving extended interval dosing of subcutaneous natalizumab, the median trough concentration was even lower.<BR><B>CONCLUSIONS: </B>Subcutaneous natalizumab can lead to lower drug concentrations, potentially limiting extended interval dosing.