Ocrelizumab May Affect Prognostic Value of JCV Antibody Index in Multiple Sclerosis

Presenting at CMSC 2022, researchers evaluated the decline in the anti-JCV antibody index in patients with MS through 2 years of ocrelizumab treatment.

Patients with multiple sclerosis (MS) treated with ocrelizumab for 2 years demonstrated declining JC virus (JCV) antibody index titers while conversion from seronegative to seropositive status rarely occurred. This suggests a decreased predictive value of the index for progressive multifocal leukoencephalopathy. These study findings were presented at the 2022 Annual Meeting of the Consortium of Multiple Sclerosis Centers (CMSC) held from June 1-4, in National Harbor, Maryland.

The JCV antibody index, an enzyme-linked immunoabsorbent assay (ELISA), detects antibodies to VP1, 1 of the structural proteins present in JCV. Infection JCV, as reflected by a seropositive antibody index result, increases the risk for developing progressive multifocal leukoencephalopathy.

Researchers evaluated the JCV antibody index of 645 patients diagnosed with MS at 6-month intervals over 2 years. Prior to ocrelizumab treatment, previous JCV antibody index documentation only existed for 560 of these 645 patients. A total of 360 patients (64.3%) were JCV seropositive (>0.4), while the remaining 200 (35.7%) were seronegative (0.0-0.2) or indeterminate (0.2-0.4).

Following 2 years of treatment with ocrelizumab, the average JCV antibody index decline was 0.257 (95% CI, -0.318 to -0.196). Patients who were initially seropositive showed a small trend for lowered antibody titers which was statistically significant, although none permanently converted to seronegative status. After 2 years, only 3 patients converted from seronegative to seropositive. Therefore, very few patients changed classifications by the end of the study.

“The small number of individuals becoming seropositive during the course of treatment is in keeping with the observation in other populations [receiving disease-modifying therapies] and is unlikely to have been the effect of the therapy,” the authors concluded. “The rarity of [progressive multifocal leukoencephalopathy] with ocrelizumab use and the results of this study indicate that measuring JCV antibody index in this population is unlikely to be of any prognostic value,” they added.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. Research was funded by industry grant.


Berger JR, Jacobs D, Wilson J, Wilson E, Virupakshaiah A, Do D. Effect of ocrelizumab on JC virus antibody index. Presented at: CMSC 2022 Annual Meeting; June 1-4, 2022; National Harbor, Maryland. Abstract DMT57.