LOS ANGELES -- Compared to standard interval dosing (SID), extended interval dosing (EID) with natalizumab was tied to a decreased risk for PML.
In an analysis of the TOUCH prescribing program data, Lana Zhovtis Ryerson, MD, of NYU Langone Health in New York City, and colleagues reported a 94% reduction in the risk for PML with EID compared with SID in the primary analysis, as well as an 88% reduction in the secondary analysis (both P<0.0001).
The study -- which only included patients who were anti-JC virus antibody positive -- looked at 1,988 patients in the EID group and 13,132 in the SID group. The three separate analyses used average dosing intervals of ≥3 to <5 weeks for SID and >5 to ≤12 weeks for EID.
The primary analysis defined EID as ≤15 infusions in the past 540 days, with SID defined as >15 infusions.
The secondary analysis defined the EID group as including patients who received consecutive EID infusions for 6 months after a first EID infusion, with ≤10 doses occurring in the prior year. SID was considered >10 doses over the previous year prior to any infusion.
After 2 or more years of treatment, the majority of SID patients switched to EID, with an average dosing interval of 35-43 days, compared with a dosing interval of 30-31 days for SID.
As the TOUCH prescribing program does not collect data on effectiveness, "additional prospective studies are needed to establish whether the effectiveness of natalizumab is maintained with EID," the authors concluded.
Disclosures
The natalizumab study was funded by Biogen, and Zhovtis Ryerson and colleagues reported relationship with industry.
Primary Source
American Academy of Neurology
Zhovtis Ryerson L, et al "Natalizumab extended interval dosing (EID) is associated with a significant reduction in progressive multifocal leukoencephalopathy (PML) risk compared with standard interval dosing (SID): analyses of TOUCH® prescribing program data" AAN 2018; Abstract P4.475.