Pfizer and Trillium Therapeutics
Deal value: $2.26 billion
Premium: 118% over the 60-day weighted average price of Trillium’s stock
Date announced:Aug. 23, 2021
Pfizer's second-largest acquisition in 2021 after its Arena Pharma takeover was its $18.50-per-share buyout of Trillium Therapeutics, claiming territory in the emerging category of cancer therapies that aim to switch off a tumor cell's "don’t eat me" signal broadcast to the immune system.
The $2.26 billion deal focused on Trillium's early-phase inhibitors of the CD47 macrophage checkpoint. The drugs are designed to unleash the innate immune system against cancers, a hot trend in oncology.
The deal added two candidates—TTI-622 and TTI-621—to Pfizer's cancer pipeline. The drugs block CD47 while simultaneously delivering an "eat me" signal to macrophages and, in the case of TTI-621, activate natural killer (NK) cells.
Pfizer’s takeover of Trillium, which closed in November, is the third major tie-up involving a CD47 specialist in the space of a couple of years.
In 2020, Gilead Sciences paid $4.9 billion to buy Forty Seven and its lead antibody magrolimab, which is in phase 3 testing for myelodysplastic syndrome and acute myeloid leukemia. Shortly afterwards, AbbVie entered into a strategic partnership with Chinese biotech I-Mab worth $2.9 billion. That deal is focused on mid-stage candidate lemzoparlimab.
Other players in what is becoming an increasingly busy category include Roche-backed ARCH Oncology (April 27, 2021 - Arch Oncology Secures $105 Million Series C Financing - to include a combination trial with pembrolizumab (KEYTRUDA) in solid tumors), ALX Oncology (512MM$US), Innovent Biologics, Surface Oncology (135MM$US) and Zai Lab. Some of those companies have also been earmarked as potential takeover candidates.
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The promise of inhibiting CD47 lies primarily in blocking a process that protects malignant cells from being engulfed and eaten by white blood cells. Experiments have also suggested that inhibiting CD47 can stimulate the malignant cells to self destruct via a process known as apoptosis or programmed cell death.
Cambridge, Massachusetts-based Trillium reported data from a clinical trial of TTI-622 as a monotherapy in hematological cancers last year, showing preliminary efficacy that Trillium said was higher than had been observed with other CD47 inhibitors.
Ahead of the Pfizer takeover, the biotech also started a phase 1b/2 program in seven different types of cancer, including solid tumors. The program is testing the drug on its own and in combination with other therapies.
For now, that includes Bristol Myers Squibb’s Onureg (azacitidine) and Amgen’s Kyprolis (carfilzomib), but there could be plenty of potential for combinations involving Pfizer's own portfolio of targeted oncology drugs and cancer immunotherapies.
With Trillium under its wing, Pfizer will take responsibility for showing whether the initial positive data translates into significant efficacy in late-stage studies, and whether TTI-621 and TTI-622 are differentiated from other CD47 inhibitors. The company has said that one key difference with the meds is that they don’t bind to red blood cells, minimizing the risk of anemia.
It's worth noting that Pfizer already owned a minority stake in Trillium and had a seat on its board, so the company had been fairly close to Trillium and would have had insight into the biotech's programs before making the move.
RELATED: Pfizer funnels $1B into protein degrader Arvinas, with more in biobucks on the table
Aside from its Arena and Trillium buyouts, Pfizer also bolstered its oncology portfolio this year with another sizeable deal, paying Arvinas a whopping $1 billion upfront for rights to develop and commercialize ARV-471, an estrogen degrader in phase 2 testing for advanced breast cancer.
The company paid $650 million in upfront cash and made a $350 million equity investment in Arvinas, with another $1.4 billion in potential milestones tied to the deal.