Patients being treated with infliximab had weakened immune responses to the first dose of the ChAdOx1 nCoV-19 (Oxford/AstraZeneca) and BNT162b2 (Pfizer/BioNTech) vaccines, compared with patients on vedolizumab (Entyvio), although a very significant number of patients from both groups seroconverted after their second dose, according to a new U.K. study of patients with inflammatory bowel disease (IBD).
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“Antibody testing and adapted vaccine schedules should be considered to protect these at-risk patients,” Nicholas A. Kennedy, PhD, MBBS, of the University of Exeter (England) and colleagues wrote in a preprint published March 29 on MedRxiv.
Infliximab is an anti–tumor necrosis factor (anti-TNF) monoclonal antibody that’s approved to treat adult and pediatric Crohn’s disease and ulcerative colitis, as well as rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, and plaque psoriasis, whereas vedolizumab, a gut selective anti-integrin alpha4beta7 monoclonal antibody that is not associated with impaired systemic immune responses, is approved to treat Crohn’s disease and ulcerative colitis in adults.
A previous study from Kennedy and colleagues revealed that IBD patients on infliximab showed a weakened COVID-19 antibody response compared with patients on vedolizumab. To determine if treatment with anti-TNF drugs impacted the efficacy of the first shot of these two-dose COVID-19 vaccines, the researchers used data from the CLARITY IBD study to assess 865 infliximab- and 428 vedolizumab-treated participants without evidence of prior SARS-CoV-2 infection who had received uninterrupted biologic therapy since being recruited between Sept. 22 and Dec. 23, 2020.
In the 3-10 weeks after initial vaccination, geometric mean concentrations for SARS-CoV-2 anti-spike protein receptor-binding protein antibodies were lower in patients on infliximab, compared with patients on vedolizumab for both the Pfizer (6.0 U/mL [5.9] versus 28.8 U/mL [5.4], P < .0001) and AstraZeneca (4.7 U/mL [4.9] versus 13.8 U/mL [5.9]; P < .0001) vaccines. The researchers’ multivariable models reinforced those findings, with antibody concentrations lower in infliximab-treated patients for both the Pfizer (fold change, 0.29; 95% confidence interval, 0.21-0.40; P < .0001) and AstraZeneca (FC, 0.39; 95% CI, 0.30-0.51; P < .0001) vaccines.
After second doses of the two-dose Pfizer vaccine, 85% of patients on infliximab and 86% of patients on vedolizumab seroconverted (P = .68); similarly high seroconversion rates were seen in patients who had been infected with SARS-CoV-2 prior to receiving either vaccine. Several patient characteristics were associated with lower antibody concentrations regardless of vaccine type: being 60 years or older, use of immunomodulators, having Crohn’s disease, and being a smoker. Alternatively, non-White ethnicity was associated with higher antibody concentrations.
Evidence has ‘unclear clinical significance’
“These data, which require peer review, do not change my opinion on the safety and efficacy of COVID-19 vaccines in patients taking TNF inhibitors such as infliximab as monotherapy for the treatment of psoriatic disease,” Joel M. Gelfand MD, director of the psoriasis and phototherapy treatment center at the University of Pennsylvania, Philadelphia, said in an interview.
Courtesy Dr. Joel M. Gelfand
Dr. Joel M. Gelfand
“First, two peer-reviewed studies found good antibody response in patients on TNF inhibitors receiving COVID-19 vaccines (doi: 10.1136/annrheumdis-2021-220289; 10.1136/annrheumdis-2021-220272). Second, antibody responses were robust in the small cohort that received the second dose of a COVID-19 vaccine. We already know that, for the two messenger RNA-based vaccines available under emergency use authorization in the U.S., a second dose is required for optimal efficacy. Thus, evidence of a reduced antibody response after just one dose is of unclear clinical significance. Third, antibody responses are only a surrogate marker, and a low antibody response doesn’t necessarily mean the patient will not be protected by the vaccine.”