Higher-than-standard doses of rituximab improved clinical response rates in patients with rheumatoid arthritis who had an incomplete B-lymphocyte depletion as determined by highly sensitive flow cytometry, judging from results from a small study.
“Not only is B-cell depletion important in determining clinical response, it can be enhanced by increasing the dose of rituximab,” according to Dr. Edward Vital of the U.K. National Institute for Health Research's Leeds (England) Musculoskeletal Biomedical Research Unit.
Rituximab is administered as two 1-g doses, “but a significant proportion [of patients] fail to achieve a EULAR response after standard therapy,” he said.
Dr. Vital and his associates used highly sensitive flow cytometry to identify 26 patients with active RA and incomplete deletion 2 weeks after they received an initial 1-g dose of rituximab. The patients were then randomized 1:1 to a total of either 2 g or 3 g rituximab.
At the end of 40 weeks, a significantly higher proportion of patients who received 3 g of rituximab had EULAR moderate/good response rates, compared with their counterparts who received 2 g (92% vs. 54%, respectively). Data from 1 year of follow-up on 20 of the patients showed EULAR moderate/good responses in 67% of patients who received 3 g vs. 27% in those who received 2 g.
Disclosures: Dr. Vital disclosed that he received research support from Roche to conduct the study.