Mark Gudesblatt, MD
One of the invisible treatment concerns is the effect of disease-modifying therapies (DMT) on vaccination, vaccination hesitancy, recurring COVID-19 variants and their ability to elude detection, and the protection of PWMS. This includes our ability to treat vaccinated PWMS if breakthrough recurrent infection occurs and identify how best to mitigate risk for recurrent infection. Prior comments have explored the impact of varied DMT on B-cell–related antibody response. With little surprise, a decreased SARS-CoV-2 antibody level is the major contributor to breakthrough SARS-CoV-2 infection in vaccinated PWMS taking various DMT, with a third vaccine dose significantly reducing the risk for infection. A prospective study (N = 1705) by Sormani and colleagues examined PWMS taking various DMT who received two doses of the BNT162b2 (BioNTech-Pfizer) (n = 1391) or mRNA-1273 (Moderna, aka CX-024414) (n = 314) SARS-CoV-2 vaccine, with most receiving a third dose. After the second dose, the only significant factor associated with risk for breakthrough infection was low antibody level (hazard ratio [HR] 0.51; P < .001), with the third dose reducing the risk for infection by 56% (HR 0.44; P = .025) during the Omicron COVID-19 wave.
In another recent prospective study, Cabeza and colleagues noted that ocrelizumab-treated PWMS who received a third SARS-CoV-2 vaccine dose had a boosted T-cell response, but there was no additive effect on the maximal T-cell response. The study included PWMS taking DMT (ocrelizumab, n = 24; fingolimod, n = 12; or no DMT, n = 10) and healthy controls (n = 12), all of whom received three SARS-CoV-2 vaccine doses (BioNTech-Pfizer or Moderna). The SARS-CoV-2–specific T-cell response in patients treated with ocrelizumab was comparable to that in PWMS who were not treated with DMT and to that in healthy controls after the second SARS-CoV-2 vaccination. However, the third SARS-CoV-2 vaccination had no additive effect on T-cell response, but it did induce a booster response ( P < .05).
The relationship and interplay of both T-cell and B-cell responses to viral infection is important to understand and appreciate. However, for PWMS who have had, do have, or will experience breakthrough infection, early use of anti-SARS-CoV-2 monoclonal antibodies (mAb) was effective and safe in treating acute COVID-19 in PWMS treated with fingolimod or ocrelizumab. Manzano and colleagues reported on an observational study including 23 PWMS, most of whom had completed the initial COVID-19 vaccine series before infection and were either untreated or treated with fingolimod+ ocrelizumab and then received anti–SARS-CoV2 mAbs (bamlanivimab + etesevimab, casirivimab + imdevimab, sotrovimab, or an undocumented formulation) for treatment of active COVID-19. In this study, 74% of PWMS were able to be managed as outpatients (median duration to mAb receipt, 4 days), and 48% of PWMS recovered from COVID-19 within 7 days after mAb receipt, with no clinical MS relapses documented during or shortly after COVID-19 (median follow-up, 18 days). No adverse events or deaths were reported in this series.
Pivotal trials and package insert information affect DMT choice and dosing, the timing of ongoing treatment, and the awareness of efficacy and potential adverse reactions. Foley and colleagues demonstrated that switching to once-every-6-weeks (QW6) dosing of natalizumab from a stable dosing of once every 4 weeks (QW4) was safe, without any clinically meaningful loss of efficacy in most patients with relapsing-remitting MS (RRMS). In the phase 3b NOVA trial (N = 499), patients with RRMS receiving stable intravenous natalizumab QW4 dosing were randomly assigned to continue QW4 (n = 248) or switch to QW6 (n = 251) natalizumab dosing. The mean number of new or newly enlarging T2 hyperintense lesions at 72 weeks was 0.20 (95% CI 0.07-0.63) with natalizumab QW6 vs 0.05 (95% CI 0.01-0.22) with natalizumab QW4, with only two of the PWMS developing 25 or more lesions; this contributed to most of the excess lesions in the QW6 dosing regimen. The safety profile was similar for both the regimens.
Both DMT choice and vaccine-related antibody production matter. Various DMT have different and problematic impact on antibody production and response, and unrecognized immune deficiency or poor antibody response are problematic as variant COVID-19 strains continue to evolve. Protection against both MS disease activity and infections from variants remain a complex issue. Establishing and maintaining protection are important. Identifying PWMS who are at high risk for poor or sustained antibody response is important in addition to the ongoing effective treatment of MS. The landscape of available DMT choice, treatment paradigms, and COVID-19 variants and COVID-19 family protection continues to evolve.