Adjusting Rituximab Dose, Timing Can Improve Response to COVID-19 Vaccination

Humoral response to COVID-19 vaccination in patients with rheumatoid arthritis (RA) treated with rituximab was notably better with an ultra-low rituximab dose and with a longer period between the most recent rituximab infusion and vaccination, according to a single-center study published in the journal Rheumatology.

“Treatment with rituximab … impairs humoral response to both COVID-19 and non-COVID-19 vaccines,” wrote lead and corresponding author Céleste van der Togt, MD, of Radboud University Medical Center in the Netherlands, and coauthors. “Thus, for optimal prevention of COVID-19 in this patient group, increasing vaccine response is of utmost importance.”

The study investigated humoral response 2 to 6 weeks after complete COVID-19 vaccination in a total of 196 patients treated with rituximab for RA at Sint Maartenskliniek, the Netherlands.

Patients treated with 200 mg rituximab showed a better humoral response after 2-dose COVID-19 vaccination compared with patients treated with 1000 mg rituximab. Although just 31 patients in the study received 200 mg rituximab, the identified effect was nonetheless statistically significant, researchers pointed out.

Additionally, timing COVID-19 vaccination longer after rituximab infusion was positively linked with a higher chance of vaccination response. Researchers reported a per-month odds ratio of 1.67.

“Based on our findings, two recommendations can be formulated,” the authors wrote. “First, COVID-19 vaccination should be timed as late as possible after the latest rituximab infusion, preferably more than one rituximab cycle (6 months). Second, rituximab should be dosed as low as possible, preferably 200 mg. The safety and feasibility of this dosage is supported by high-quality evidence.”

—Jolynn Tumolo

Reference
Van der Togt CJT, Ten Cate DF, den Broeder N, Rahamat-Langendoen J, van den Bemt BJF, den Broeder AA. Humoral response to coronavirus disease-19 vaccines is dependent on dosage and timing of rituximab in patients with rheumatoid arthritis. Rheumatology. 2022;61(SI2):SI175-SI179