Trillium Therapeutics

Trillium Therapeutics operated as a clinical-stage immuno-oncology company, primarily focused on developing therapies for cancer treatment. Founded in 2004 and headquartered in Mississauga, Canada, the company dedicated its resources to targeting key immunoregulatory pathways that cancer cells exploit to evade the immune system.

The company's core business revolved around its portfolio of biologics designed to enhance the innate immune system's ability to detect and destroy cancer cells. A significant milestone in the company's history was its acquisition by Pfizer in November 2021 for an aggregate purchase price of approximately $2.22 billion. This acquisition followed an initial investment of $25 million by Pfizer in September 2020 through its Breakthrough Growth Initiative, which also led to a Pfizer executive joining Trillium's Scientific Advisory Board. The acquisition was structured as a statutory plan of arrangement under the Business Corporations Act of British Columbia, resulting in Trillium becoming a wholly-owned subsidiary of Pfizer and its shares being delisted from the Nasdaq and Toronto Stock Exchange.

Trillium's main products in development were two lead molecules, TTI-622 and TTI-621, which are novel SIRPα-Fc fusion proteins. These proteins function by blocking the signal-regulatory protein α (SIRPα)–CD47 axis, an immune checkpoint that cancer cells use to send a "don't eat me" signal to evade destruction by the immune system. The technology was designed to not only block this inhibitory signal but also to deliver a pro-phagocytic "eat me" signal to macrophages. A key feature of these molecules is their design to have limited binding to red blood cells, mitigating the risk of anemia, a common issue with other CD47-targeted therapies. These candidates were in Phase 1b/2 clinical development across several indications, with a primary focus on hematological malignancies such as various types of leukemia, multiple myeloma, and lymphoma. The groundbreaking research that led to the development of TTI-621 began at UHN's Princess Margaret Cancer Centre and The Hospital for Sick Children (SickKids), stemming from a collaboration between Drs. John Dick, Jean Wang, and Jayne Danska.

Keywords: immuno-oncology, CD47 inhibitor, SIRPα-Fc fusion protein, cancer therapy, hematological malignancies, Pfizer acquisition, TTI-622, TTI-621, innate immune system, clinical-stage, macrophage checkpoint, biologics, leukemia treatment, lymphoma treatment, multiple myeloma, immune checkpoint inhibitor, drug development, oncology pipeline, cancer research