Phase 1-2 study of TI-061 alone and in combination with other anti-cancer agents in patients with advanced malignancies.

Abstract

TPS3109 Background: The cell surface protein CD47 is expressed or over-expressed on many tumor types. CD47 binds to signal regulatory protein alpha (SIRPα) on macrophages resulting in a “don’t eat me” signal that blocks host cell phagocytosis of the tumor cells, thus allowing them to escape removal by the innate immune system. Recent data indicate that anti-CD47 antibodies also contribute to an effective anti-tumor T cell response in immune-competent mice. Therefore, anti-CD47 antibodies are a new class of immune checkpoint inhibitors that modulate both the innate and adaptive immune systems. Ti-061 is a novel IgG4 humanized monoclonal antibody that specifically binds to CD47 with Kd values range from 100 – 500 pM. Ti-061 exhibits cross-species binding to cynomolgus monkey, mouse and rat CD47, enabling efficacy and toxicity testing across species. Ti-061 binds to CD47 on RBCs; however, it does not cause agglutination of RBCs in vitro from any of the species tested. Ti-061 exhibits anti-tumor activity in several in vivo mouse tumor models. This ongoing Phase 1-2 study will assess the safety, efficacy, pharmacokinetics (PK) and pharmacodynamics (PD) of Ti-061 alone and in combination with other anti-cancer agents in patients with advanced malignancies. Methods: Part A is an open-label, dose-escalation study of Ti-061 administered as a weekly 1-hour IV infusion at doses ranging from 1 to 20 mg/kg. Once the MTD/RP2D or “active dose” is determined, patients with specific solid tumors and high CD47 expression will be enrolled in 4 or more expansion cohorts. Up to 160 patients with histologically confirmed solid tumors, ECOG PS 0-1, adequate blood counts (Hb≥ 10 g/dL), organ function, and archival or fresh tumor tissue will be enrolled in Part A, and will be treated until disease progression, unacceptable toxicity, or withdrawal. Primary endpoint is safety, which will be assessed using NCI-CTCAE v4.03. Secondary endpoints include PK, PD, objective response rate (ORR) and progression-free survival (PFS), which will be assessed using RECIST v1.1. The results of this study will support further development of Ti-061 in combination with checkpoint inhibitors (Part B) and other anti-cancer agents.