As the COVID-19 pandemic swept the world, rheumatologists wondered if their patients would be uniquely vulnerable. As time has passed, immunologists have learned that although the innate immune system and T cells are important in the early antiviral response to COVID-19, B cells also appear to be crucial—information that further suggests a special susceptibility of patients with rheumatological disease.
One of the first investigations of the vulnerabilities of patients with inflammatory rheumatic and musculoskeletal diseases used the French RMD COVID-19 cohort.1 The objective of the data analysis of this cohort was to identify epidemiological characteristics associated with severe disease in patients with both rheumatic disease and COVID-19. That first analysis found several factors, including a signal for rituximab. However, the findings were limited because the analysis did not take into consideration the main characteristics and potential confounders of patients receiving rituximab. To date, although it was reasonable to assume rituximab’s effect on B cells may compromise a response to COVID-19, no cohort studies have specifically addressed whether rituximab adversely affects COVID-19 outcomes.
A recent analysis of the French RMD COVID-19 cohort compared COVID-19 severity in patients with inflammatory rheumatic and musculoskeletal diseases who were treated with rituximab with those who were not. The analysis revealed patients receiving rituximab therapy experience more severe COVID-19. Jerome Avouac, MD, PhD, a rheumatologist at the Centre Universite de Paris, France, and colleagues concluded from their analysis of the French COVID-19 RMD cohort that rheumatologists should use caution when prescribing rituximab to patients with inflammatory rheumatic and musculoskeletal diseases. They published the association between rituximab therapy and admission to an intensive care unit (ICU) or death online March 25 in Lancet Rheumatology.2
“The findings support what we already knew and thought,” says Cassandra Calabrese, DO, a rheumatologist at Cleveland Clinic in Ohio, noting that the study reiterates what rheumatologists have learned from the COVID-19 Global Rheumatology Alliance data. “This [association] is something we’ve been long aware of and made practice changes as a result of the knowledge.”
The COVID-19 Global Rheumatology Alliance was created in March 2020 with the mission to collect, analyze and disseminate information about COVID-19 and rheumatology to patients, physicians and other relevant groups to improve the care of patients with rheumatic disease. The international database allows any provider to enter data, and it currently includes thousands of patients, symptoms and medications. Although data from the Alliance have been analyzed and published in multiple reports, the data do not allow for a cohort study.
In the current cohort study, the investigators collected data on patients treated with rituximab, as well as a control group of patients who were eligible for rituximab therapy by indication but did not receive it. The researchers adjusted for the main comorbidities associated with COVID-19 severity and rituximab prescription, finding comorbidities had a definite effect on risk of death. The study not only revealed an association between rituximab therapy and more severe disease, but it also found the time between the last infusion of rituximab and first symptoms of COVID-19 was significantly shorter in patients who developed severe COVID-19 than those with moderate or mild forms. This finding further supports a direct relationship between rituximab and severe COVID-19 disease.