Abstract 4083: Pre-clinical development of IAMA-005, a long-acting cytokine fusion of modified IL-2 and IFN-α

Abstract

Abstract In 1990s, both IL-2 and IFN-α were approved as the first two immunotherapies for metastatic melanoma and renal cell carcinoma; IFN-α was also approved for hairy cell leukemia. Although the response rates are relatively low, along ~25%, those who responded have long term survival benefits. However, the severe toxicity especially in high dose prohibited their broad use in oncology. Recently, there have been tremendous interests in modifying these two cytokines in the efforts to reduce the toxicity and enhance the activity. One such effort is to enhance the binding of IL-2 to the intermediate affinity β/γ receptors, which are expressed and function on CD8 T cells and NK cells. Another effort is to reduce the binding of IL-2 to high affinity α/β/γ receptors which mostly expressed on Treg and stimulate the growth of Treg cells, which suppress immune responses. Recently, whether it’s better to target intermediate affinity or high affinity for cancer therapy has become controversial with some studies showing that high affinity receptor engagements are required for robust anti-tumor activity while others favoring intermediate affinity receptor engagement for better efficacy; However, the clinical comparison is still lacking to be sure which approach is better. Here we have developed a long-acting novel IL-2-Fc-IFN-α fusion molecule termed IAMA-005 that has mutations to reduce the toxicity effects of IL-2 and IFN-α. We have characterized this molecule preclinically both in vitro and in vivo. IAMA-005 has demonstrated a potent tumor cell killing activities in numerous cancer cell lines including BT-474, SK-OV-3, NCI-N87, OE19, HCC-1954, MDA-MB-231, MDA-MB-468. When combined with IAMA-004 (a Her2-CD47-CD16 tri-specific antibody) in vitro, the tumor cell killing activities were dramatically increased. In addition, IAMA-005 was also tested in patient-derived Ex-Vivo fluids (one malignant pleural effusion and one malignant asities) and demonstrated excellent tumor cell killing efficacies. In addition, the killing activities of IAMA-005 could be attributed to the specific part of the fusion molecule because of the TME immune cell compositions. The in vivo assays to demonstrate efficacy and safety are ongoing and will be presented in the poster. These results suggest that this fusion cytokine molecule may be used in monotherapy in certain indications and an excellent complementary therapeutic to antibody targeted therapies or immunotherapies when used in combination. Citation Format: Liming Liu, Zhen Han, Yang Fan, Qi Pan. Pre-clinical development of IAMA-005, a long-acting cytokine fusion of modified IL-2 and IFN-α [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4083.