Efficacy and retention rate of rituximab in Japanese rheumatoid arthritis patients with a history of other iatrogenic immunodeficiency-associated lymphoproliferative disorders

Objective The present study aimed to evaluate the efficacy, safety, and retention rate of rituximab (RTX) in Japanese rheumatoid arthritis (RA) patients with a history of other iatrogenic immunodeficiency-associated lymphoproliferative disorders (OIIA-LPD). Methods Between January 1, 2014, and July 31, 2024, 3,392 RA patients were registered in our institutional database, and 74 of these had OIIA-LPD. Among patients who achieved remission after the onset of OIIA-LPD, those who subsequently received RTX were retrospectively identified. Clinical data, including the Disease Activity Score for 28 joints-C reactive protein (DAS28-CRP) value, Clinical Disease Activity Index (CDAI) score, adverse events, and RTX retention rate, were analyzed. Results Fourteen patients received RTX for RA after OIIA-LPD remission. The mean DAS28-CRP value at baseline and at month 6, 12, 24, and 36 was 3.91 ± 1.40, 3.03 ± 3.20, 2.45 ± 1.09, 2.22 ± 0.62, and 1.93 ± 0.78, respectively. The respective CDAI score was 15.2 ± 7.74, 4.91 ± 3.80, 6.19 ± 4.46, 5.08 ± 3.03, and 4.18 ± 3.28. Four infections were observed. The RTX retention rate at month 12, 24, and 36 was 85.1%, 76.6%, and 76.6%, respectively. Conclusion Even in real-world clinical practice, RTX demonstrated long-term efficacy in reducing disease activity in Japanese RA patients with a history of OIIA-LPD. RTX appears to be a viable treatment option for this patient population.