Checkpoint Inhibitor Induced Colitis and Arthritis -Immunomodulation With IL-6 Blockade and Exploration of Disease Mechanisms

Immune checkpoint inhibitors (ICI) targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and the programmed cell death protein-1 (PD-1)/programmed cell death ligand-1 (PD-L1) pathway might induce inflammatory potentially serious and even lethal immune related Adverse Events (irAEs). Diarrhea and/or colitis are ones of the most frequently reported irAEs in patients taking ICI, occurring after an average of three infusions. The incidence is higher among patients taking combination anti-CTLA-4/ anti-PD-1 therapy (44%) than those receiving anti-CTLA-4 (23-33%) or anti-PD-1 (≤19%) monotherapy. The most common autoimmune and musculoskeletal irAEs reported in clinical trials are represented by arthralgia and arthritis. The incidence of arthralgia and/or inflammatory arthritis secondary to nivolumab therapy ranges from 5% to 16% and 5%, respectively. Although the immune mechanisms underlying irAEs have not been fully elucidated, studies suggest that Th17 and Tregs cells, increases in expression of immunologically-related genes, eosinophilia, microbiome among others and cytokines may be involved in the pathophysiology of immune-related complications in some diseases that resemble irAEs, such as colitis and rheumatic manifestations. Previous studies report Th-17, that drives interleukin-17 (IL-17) production, as a key mediator of many immune diseases, including inflammatory bowel disease and ICI-induced colitis, and IL-17 elevations have been observed in experimental colitis. Importantly, interleukin-6 (IL-6) promotes the differentiation of naïve CD4+ T cells into Th17 cells (17), and IL-6 inhibition may rebalance the altered Th17-Treg axis without inhibiting the Th1-CD8+ T-cell subsets that govern antitumor immunity. An imbalance of Th17/Treg may cause the onset and progression of immune-mediated side effects. Thus, a 3-fold increase of IL-17 and IL-6 by week 12, concomitant with the development of fulminant colitis has been reported in a patient who developed presumed ipilimumab-induced colitis. These findings raise the possibility of using IL-6 blockade as a strategy for treating colitis and arthritis induced by immune checkpoint blockade.

Inclusion criteria

• Signed informed consent
• Subjects must have signed and dated an IEC approved written informed consent form in accordance with regulatory and institutional guidelines. This must be obtained before the performance of any protocol related procedures that are not part of normal subject care
• Subjects must be willing and able to comply with scheduled visits, treatment schedule, laboratory testing, and other requirements of the study
• Patients with solid tumors treated with PD-1, PD-L1 and /or CTLA-4 inhibitors
• Diarrhea and/or colitis CTCAE grade ˃ 1 and/or arthritis CTCAE grade ˃ 1 induced by PD-1, PD-L1 and /or CTLA-4 inhibitors
• Age 18 years and older
• ECOG/WHO Performance Status (PS) 0-1, PS of 2 due to ongoing irAEs is allowed
• White blood cell count (WBC) ≥ 2 x 10⁹/L and/or absolute neutrophil count (ANC) ≥ 1.0 x 10⁹/L
• Platelet count ≥ 50 x 10⁹/L
• Serum bilirubin ≤ 1.5 x upper limit of normal (ULN)
• ASAT/ALAT ≤ 5 x ULN

Exclusion criteria

• History of allergy to study drug component
• Patients should be excluded if they have a condition and/or other irAEs requiring systemic treatment with either corticosteroids (> 10 mg daily prednisone equivalents) or other immunosuppressive medications within 14 days of study drug administration
• Females of childbearing potential or males of reproductive potential who are not willing to use an effective method of contraception, such as oral, injected, or implanted hormonal methods of contraception, intrauterine device or intrauterine system, condom or occlusive cap (diaphragm or cervical/vault caps) with spermicidal foam, gel, film, cream, suppository, male sterilization, or true abstinence throughout study and for a minimum of 3 months after study drug therapy.