A phase I study of isunakinra, an IL-1 alfa/beta inhibitor, in combination with nivolumab for patients with solid tumors refractory to standard therapies.

Abstract

e14580 Background: Interleukin-1 is a master cytokine produced by macrophages (IL-1 β) and released upon cell death (IL-1 α). IL-1 upregulates other cytokines in the tumor microenvironment (i.e. IL-6 and IL-8), drives chronic non-resolving inflammation in the tumor, induces cancer cell invasion and metastasis (EMT), has profound effects on immune cells and cancer associated fibroblasts and can attract granulocytic myeloid suppressor cells to the tumor (PMN-MDSC), that in turn inhibit cytotoxic T cell responses. Isunakinra is a small recombinant protein resembling IL-1Ra, with an inhibitory potency 10-20 times higher, that binds to the IL1-R1 and blocks activation of the receptor by both IL-1α and IL-1β. We conducted a phase I dose escalation study with isunakinra as monotherapy and in combination with a PD-1 inhibitor in patients with locally advanced or metastatic solid tumors that had exhausted all treatment options. Methods: Enrolled patients with refractory metastatic solid tumor, ECOG 0-2, on a 3 + 3 dose-escalation trial at three dose levels of isunakinra (15, 25 or 50 mg). Isunakinra was self-administered once daily SC for three weeks followed by 4 additional weeks in combination with nivolumab Q4W at 480 mg, flat dose to complete the DLT period of 7 weeks. Thereafter, isunakinra/nivolumab was continued until week 28. Primary endpoints: DLTs, safety, and pharmacokinetics. Secondary endpoints: tumor and immune monitoring. Results: Enrolled fifteen patients with metastatic or unresectable locally advanced solid tumors (colorectal, pancreatic, triple-negative BC, anal, prostatic, CCA, and appendix) that had received 2-5 prior lines of therapy. Seven SAE occurred in three rapidly deteriorating subjects, all disease related hospitalizations, leading to study withdrawal during the DLT period. No DLTs, irAE or predefined laboratory deviations occurred in any subject. The highest dose, 50 mg, was selected as RP2D. Twelve subjects completed visit week 8, six of them week 12, and four completed the trial. One patient with metastatic colon cancer (MSS, KRAS mut, high TMB) was granted extended treatment for PR and continued response at end of study. Isunakinra exposure totaled 1575 daily doses, 81% during combination with nivolumab, t 1/2 5 hours with no accumulation over time. At 50mg of isunakinra, plasma levels where well above 100 ng/mL, a target for complete IL-1 inhibition. Conclusions: Isunakinra is safe and well-tolerated in combination with standard dose nivolumab. Ongoing expansion cohorts and future studies will explore the safety and efficacy of isunakinra in specific tumors and with other immunotherapy combinations. Clinical trial information: NCT04121442 .