Research led by University College London (UCL) suggests the presence of anti-drug antibodies (ADA) predict infusion-related reaction (IRR) with rituximab (RTX) in patients with systemic lupus erythematosus (SLE).
The study recruited 57 patients from the lupus clinic at UCL. All patients were receiving RTX for active SLE for the first time. Confirmed IRRs were recorded. Baseline characteristics including complement C3 (C3), double-stranded DNA antibody titres (dsDNA) and British Isles Lupus Assessment Group (BILAG) score were recorded at the time of treatment and at each subsequent clinic visit. CD19 positive lymphocyte (CD19) levels were measured at one and six months following treatment.
ADAs were identified in 37 per cent of patients following treatment. ADAs were more common in males (P=.04). There was no significant difference in concomitant treatment, disease manifestation and ethnicity.
At the time of treatment, there was no difference in C3, dsDNA titres or BILAG. At six months post-treatment, ADA-negative patients showed a significant increase in C3 levels (P=.003) and reduction in dsDNA antibody binding (P=.008).
In ADA-positive patients, although C3 was normalised at six months (P=.007), there was no observed improvement in dsDNA titres (P=.96). Both ADA-positive and ADA-negative patients showed significant improvement in global BILAG score six months after treatment (P<.0001). Contrary to previous studies, there was no difference in CD19 between ADA-positive and ADA-negative patients at either one or six months post-treatment.
Of the 57 patients recruited, 25 patients underwent retreatment with RTX (18 ADA-positive and 7 ADA-negative). All ADA-positive patients developed IRRs. No IRR was reported in ADA-negative patients (P<.001). Severe reactions resulting in hospitalisation were seen in three cases in which ADA titres were >1500 IU.
Writing in the Annals of the Rheumatic Diseases, the authors said: “If validated, these findings may support routine screening for ADA prior to treatment with RTX, thus potentially identifying patients at risk of developing IRR and prompting greater caution and enhanced surveillance.”
