Anti-IL-6R Ab tocilizumab to treat paraneoplastic inflammatory syndrome of solid cancers.

Background: Paraneoplastic inflammatory syndrome (PIS) with fever and biological inflammation is a rare but severe condition often caused by the systemic production of interleukin 6 (IL-6) by cancer cells. We report on the efficacy of tocilizumab, an anti-IL-6 receptor antibody, in 35 patients with severe PIS.

Patients and methods: All 35 patients with solid cancers (sarcomas, lung carcinoma, and breast carcinoma) diagnosed with a PIS from 2019 to 2024 treated with tocilizumab were analyzed in this single-center study (health authorities' approval R201-004-478). Patients' characteristics and clinical and biological effects of tocilizumab administration are presented.

Results: Thirty-five (97%) patients had paraneoplastic fever. The median performance status (PS) was 2 (range 1-4). Forty percent of patients had lost 10% of body weight. All had increased serum C-reactive protein (CRP) levels (median 212 mg/l), and 74% and 48% had increased polymorphonuclear leukocyte (PMN) and platelet counts, respectively. Ninety-four percent had inflammatory anemia. Tocilizumab was given once in 23 (66%) patients and more than once in 12 patients. All patients experienced resolution of paraneoplastic fever, and 11 (31%) had improved PS. CRP, PMN, and platelet count decreases were observed in 100%, 85%, and 94% of patients, respectively. Seventy-seven percent of patients had increased hemoglobin levels. CRP and inflammatory symptoms often relapsed 4-6 weeks after tocilizumab in patients receiving only one injection.

Conclusions: Tocilizumab is an efficient treatment for severe PIS providing significant improvement in clinical symptoms and biological abnormalities.