Abstract 4028: Nanocyclix^®ALK2 Inhibitors to overcome cancer-induced anemia

Introduction: Anemia is a condition characterized by low Hemoglobin levels. Anemia is observed during tumor development through the release of inflammatory cytokines, which will affect iron availability, a key component of red blood cells. In recent years, consequences of anemia of cancer on patients is getting growing recognition from a quality of life perspective, as well as its impact on the treatment scheme and hospitalization duration. Cancer-induced anemia has been identified in 30% of treatment-naive cancers (ECAS study, 2011 - WHO methodology). The proportion of anaemic patients reaches 70% following treatments, such as chemotherapies. Current approaches consider erythropoietin derivatives, formulated iron or transfusions, which does not address underlying chronic inflammation. Moreover, their use is limited as a consequence of toxicities (EPO, formulated iron) or availability (transfusion). Increased expression of Hepcidin, a peptidic hormone regulating the storage of bioavailable iron, has been demonstrated as downstream effector of key inflammatory cytokines activation of ALK2/Smad axis. ALK2 (Activin-like receptor kinase 2) plays a critical role in the Smad signaling pathway and the production haemoglobin, through the regulation Hepcidin production in the liver. As a consequence, the selective inhibition of ALK2 as emerged as a valuable target for the treatment of Hepcidin-driven anemia of cancer to provide an alternative to current treatments. Results: OD52, a potent and selective macrocyclic ALK2 inhibitor identified from Nanocyclix® technology platform, was used as in vitro pharmacological tool to investigate the impact of ALK2 inhibition on Hepcidin expression level in HepG2 cells, as well as in mice hepatocytes. BMP6-induced expression of Hepcidin mRNA was completely inhibited by LDN-193189 to low detectable levels, whereas OD52 normalized its expression. Further validation was performed in mice hepatocytes, where OD52 decreased Hepcidin expression to a lower extend as compared with LDN-193189. These experiments confirmed the importance of selectivity within BMP-kinase receptor family, where ALK3 component represents an undesired off-target. In vivo evaluation of the compound in the acute model of turpentine-induced anemia demonstrated a normalization of haemoglobin level. In contrast, LDN-193189 increased haemoglobin above vehicle group to a level mimicking hemochromatosis, likely due to its ALK3 component. Through further medicinal chemistry optimization, OD66 was identified as suitable in vivo pharmacological tool and was evaluated in a cancer-induced anemia mouse model. The compound demonstrated a normalization of haemoglobin levels to comparable levels with the tumor-free group without displaying toxicity. Conclusion: The identification of potent and selective Nanocyclix® ALK2 inhibitors and their evaluation in relevant in vitro and in vivo models demonstrated a normalization of haemoglobin levels through the modulation of Hepcidin expression. This collaborative work warrants further optimization towards the identification of a preclinical candidate. Citation Format: Pascal Benderitter, Josselin Caradec, Edwige Nicodeme, Anne Bouillot, Sophie Vaulont, Benoit Viollet. Nanocyclix® ALK2 Inhibitors to overcome cancer-induced anemia [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4028.