TORONTO -- Trillium Therapeutics Inc. has signed a deal to be bought by Pfizer Inc. in an agreement valued at US$2.26 billion.

Under the plan, Pfizer will pay US$18.50 per share in cash for the Mississauga, Ont.-based biotechnology company.

Trillium is developing treatments to enhance the ability of a patient's immune system to detect and destroy cancer cells.

The acquisition follows Pfizer's US$25 million investment in Trillium in September 2020.

The deal is subject to customary closing conditions, including approval by a two-thirds majority vote by Trillium shareholders.

Trillium shares were up US$11.48 at US$17.57 in trading on the Nasdaq market, while they were up C$14.60 at C$22.41 on the Toronto Stock Exchange.

This report by The Canadian Press was first published Aug. 23, 2021