Pfizer has strengthened its oncology pipeline with a deal to acquire the clinical stage immuno-oncology company Trillium Therapeutics for $2.26 billion.   Trillium’s portfolio includes biologics that are designed to enhance the ability of patients’ innate immune system to detect and destroy cancer cells. Its two lead molecules, TTI-622 and TTI-621, block the signal-regulatory protein α (SIRPα)–CD47 axis, which is emerging as a key immune checkpoint in hematological malignancies. TTI-622 and TTI-...