Pfizer swallows CD47 biotech Trillium in $2.3B takeover

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Pfizer’s bet on Trillium sees it join Gilead and AbbVie as the big beasts in the CD47 space. (Delmaine Donson/iStock/Getty Images Plus/Getty Images)

Biotechs targeting the “don’t eat me” signal cancer cells use to avoid the immune system are getting gobbled up. Pfizer is the latest company to buy its way into the space, splashing out $2.3 billion to acquire Trillium Therapeutics for its early-phase inhibitors of the CD47 macrophage checkpoint.

Trillium, like peers such as Forty Seven and Arch Oncology, has identified CD47 blockade as a way to unleash the power of the innate immune system against tumors. The two candidates are designed to block CD47 while simultaneously delivering an “eat me” signal to macrophages and, in the case of TTI-621, activating natural killer (NK) cells.

Pfizer sees enough promise in the prospects to bet $2.26 billion on Trillium. At $18.50 per share, the takeover represents a 118% premium over the 60-day weighted average price of Trillium’s stock and a more than 200% premium over the biotech’s closing price yesterday.

In return for the outlay, Pfizer will gain ownership of TTI-621 and TTI-622. TTI-621 is designed to deliver a stronger “eat me” signal and activate NK cells, differentiating it from its otherwise similar sibling TTI-622.

Trillium shared updated data from a clinical trial of TTI-622 in blood cancer patients earlier this year. The update revealed a slight dip in the response rate, despite the most recent patients getting a high dose, but still pointed to TTI-622 having greater efficacy as a monotherapy than rival CD47 inhibitors. The drugs will be used in combinations, but the monotherapy efficacy is still a positive early sign.

RELATED: Trillium unveils CD47 clinical research priorities as investors await solid tumor data

Pfizer will now take responsibility for showing whether that positive sign translates into significant efficacy in later-stage studies. Trillium is enrolling blood cancer patients in three clinical trials that are giving TTI-622 in combination with drugs including Amgen’s Kyprolis and is gearing up to start a clutch of monotherapy and combination studies of both of its CD47 inhibitors over the coming year.

The slate of studies will go some way toward validating or disproving Trillium’s belief that its molecules are differentiated from other CD47 inhibitors. Magrolimab, which Gilead acquired in its $4.9 billion takeover of Forty Seven, is leading the race. But features of TTI-621 and TTI-622 such as the fact they don’t bind to red blood cells, minimizing the risk of anemia, could give Trillium an edge.

Pfizer’s bet on Trillium sees it join Gilead and AbbVie as the big beasts in the CD47 space. AbbVie  paid I-Mab $180 million upfront for rights to CD47 inhibitor lemzoparlimab outside of greater China. 

Trillium’s share price has been on a roller coaster as interest in CD47 has increased, rising from less than $0.30 in late 2019 to $20 a year later. The stock has fallen throughout 2021, enabling Pfizer to pay a hefty premium but still bag Trillium for less than its 52-week high.