Registry Data Suggest That Rituximab is Safe and Efficacious in Refractory Lupus

Despite advances in the treatment of systemic lupus erythematosus (SLE) in recent years, a number of patients are refractory to conventional immunosuppressive therapies, or require unacceptably high doses of glucocorticoids for adequate disease control. Because B cells play a role in SLE, rituximab has been proposed as a potential treatment for SLE. However, data on the use of rituximab in this indication has been far from clear; 2 randomized controlled trials of rituximab in patients with SLE failed to meet their primary endpoints, while open-label trials have reported the drug’s efficacy in patients with refractory SLE.

In a paper newly published in Rheumatology, researchers used the British Isles Lupus Assessment Group Biologics Register to describe the baseline characteristics of patients in the United Kingdom who were initiating biologic therapy during the first 5 years of the register, and to evaluate the early efficacy of rituximab treatment in the first 6 months.

Patients (n = 270) with SLE who were aged 5 years or older and had started a new biologic therapy in the past 12 months were included. Patients were followed up at 3, 6, and 12 months, then annually for at least 2 years. Most patients were women (92%), the mean disease duration was 8.4 years (standard deviation, 8.7 years), and the majority (60%) were white. Most (74%) had 1 or more comorbidity. In total, 91% of patients were taking antimalarial drugs, and 93% were taking glucocorticoids. Among patients who started a biologic, 97% initiated treatment with rituximab.

A total of 178 patients who received rituximab completed baseline and 6-month assessments. At 3 months, 91 (51%) patients had responded to rituximab treatment, and at 6 months, 88 (49%) had responded. Another 9 (5%) patients—all of whom had required unacceptably high levels of steroids—experienced no worsening in disease control over 6 months after treatment with rituximab, and were able to reduce their steroid dosages.

A major clinical response was achieved by 33 (18.4%) patients. After rituximab treatment, disease activity increased in 26 (15%) patients at 3 months and 33 (19%) patients at 6 months, however.

There were 185 infections reported in 82 (30%) of patients, with respiratory and urinary tract infections most commonly reported.

More work will be necessary to identify predictors of response to rituximab, but, say the authors, “It is notable that almost one in five patients achieved a major clinical response at 6 months.” The authors conclude that rituximab appears to be safe and efficacious in treating refractory SLE, and that as additional biologic agents become available, inclusion of these agents in the register will allow for real-world comparison of treatments in identifying which patients will benefit from biologic therapies.

Reference

McCarthy EM, Sutton E, Nesbit S, et al. Short-term efficacy and safety of rituximab therapy in refractory systemic lupus erythematosus: results from the British Isles Lupus Assessment Group Biologics Register. Rheumatology. 2018;57(3):470-479. doi: 10.1093/rheumatology/kex395.