
Contributions
Abstract: P1238
Type: Poster
Abstract Category: Therapy - disease modifying - Long-term treatment monitoring
Background: John Cunningham virus (JVC) antibody serostatus is being utilized to stratify risk of developing progressive multifocal leukoencephalopathy (PML) in natalizumab infusing patients with multiple sclerosis (MS). In the US prescribing information for natalizumab, seroconversion is reported to be 3-8% annually. Findings from recent studies are inconsistent regarding the impact of natalizumab therapy duration on the rate of JCV seroconversion and index values. The aim of this study was to characterize serostatus changes longitudinally in a long-term natalizumab treated US cohort.
Methods: A total of 981 patients were tested for anti-JCV antibodies using the STRATIFY JCV Gen2 assay between Jan 2013 and Mar 2016. Of these, 552 had a first and last test separated by at least 180 days. Patients were further divided into two infusing cohorts: Group 1 - First test occurring after the initiation of natalizumab (n = 411); Group 2 - First test occurring prior to the initiation of natalizumab (n = 141).
Results: At baseline, 981 patients were anti-JCV antibody seropositive (60%) and 393 (40%) were seronegative. For Group 1, the average time between the first and last test was 35.5 months and the natalizumab treatment duration was 81.7 months. During the testing period 222 patients remained positive (54.0%), 146 remained negative (35.5%), 31 switched from negative to positive (7.5%), and 12 switched from positive to negative (2.9%). For Group 2, the average time between the first and last test was 19 months and the natalizumab treatment duration was 15.1 months. During the testing period 58 remained positive (41.1%), 67 remained negative (47.5%), 11 switched from negative to positive (7.8%), and 5 switched from positive to negative (3.5%). The annualized seroconversion rates for Group 1 and Group 2 were 6.0% and 9.0%, respectively. Conversely, the annualized seroreversion rates were 1.8%, 5.1%, respectively.
Conclusion: Baseline seroprevalence, without respect to previous or current therapies, is similar to that reported in other MS populations. For both long-term natalizumab patients and those initiating therapy, the net change results in an annualized seroprevalence rate increase of 4.2% and 3.9%, respectively. Natalizumab therapy did not appear to alter the conversion rate. Further analysis of anti-JCV antibody index levels will also be reported.
Disclosure: Tamara Hoyt has nothing to disclose.
Angelene Christensen has nothing to disclose.
Ryan Metzger owns stock in Biogen.
Dr. Foley participates in the Speakers´ Bureaus for Biogen, Genentech-Roche, Genzyme and Accorda. Dr. Foley advises for Biogen, Genentech-Roche, and Genzyme.
Abstract: P1238
Type: Poster
Abstract Category: Therapy - disease modifying - Long-term treatment monitoring
Background: John Cunningham virus (JVC) antibody serostatus is being utilized to stratify risk of developing progressive multifocal leukoencephalopathy (PML) in natalizumab infusing patients with multiple sclerosis (MS). In the US prescribing information for natalizumab, seroconversion is reported to be 3-8% annually. Findings from recent studies are inconsistent regarding the impact of natalizumab therapy duration on the rate of JCV seroconversion and index values. The aim of this study was to characterize serostatus changes longitudinally in a long-term natalizumab treated US cohort.
Methods: A total of 981 patients were tested for anti-JCV antibodies using the STRATIFY JCV Gen2 assay between Jan 2013 and Mar 2016. Of these, 552 had a first and last test separated by at least 180 days. Patients were further divided into two infusing cohorts: Group 1 - First test occurring after the initiation of natalizumab (n = 411); Group 2 - First test occurring prior to the initiation of natalizumab (n = 141).
Results: At baseline, 981 patients were anti-JCV antibody seropositive (60%) and 393 (40%) were seronegative. For Group 1, the average time between the first and last test was 35.5 months and the natalizumab treatment duration was 81.7 months. During the testing period 222 patients remained positive (54.0%), 146 remained negative (35.5%), 31 switched from negative to positive (7.5%), and 12 switched from positive to negative (2.9%). For Group 2, the average time between the first and last test was 19 months and the natalizumab treatment duration was 15.1 months. During the testing period 58 remained positive (41.1%), 67 remained negative (47.5%), 11 switched from negative to positive (7.8%), and 5 switched from positive to negative (3.5%). The annualized seroconversion rates for Group 1 and Group 2 were 6.0% and 9.0%, respectively. Conversely, the annualized seroreversion rates were 1.8%, 5.1%, respectively.
Conclusion: Baseline seroprevalence, without respect to previous or current therapies, is similar to that reported in other MS populations. For both long-term natalizumab patients and those initiating therapy, the net change results in an annualized seroprevalence rate increase of 4.2% and 3.9%, respectively. Natalizumab therapy did not appear to alter the conversion rate. Further analysis of anti-JCV antibody index levels will also be reported.
Disclosure: Tamara Hoyt has nothing to disclose.
Angelene Christensen has nothing to disclose.
Ryan Metzger owns stock in Biogen.
Dr. Foley participates in the Speakers´ Bureaus for Biogen, Genentech-Roche, Genzyme and Accorda. Dr. Foley advises for Biogen, Genentech-Roche, and Genzyme.