London drug developer Cytospire said Tuesday it raised £61 million, or $83 million, to finance its twist on a popular class of cancer drugs.
Cytospire is making a new form of “T cell engagers,” a type of cancer immunotherapy that directs immune cells to diseased ones. Several T cell engagers are now approved to treat blood cancers, and others are being tested against solid tumors and immunological diseases. By and large, these treatments are dual-targeting antibodies that latch onto a T cell receptor, “CD3,” as well as a protein flag of interest on another cell type.
Cytospire, by comparison, is designing treatments that specifically draw out all “gamma delta” T cells, a unique subset of T cells able to rapidly wipe out infected or diseased cells. According to CEO Natalie Mount, gamma delta T cells are already present in the immune-suppressing barrier, or “tumor microenvironment,” cancers use to protect themselves — making them more fit to deliver an impact than other T cell types. They can also better detect differences between target antigens on tumor cells and healthy ones, she said.
Cytospire hopes these distinctions will help lead to therapies that can broaden the reach of T cell engagers, which have largely struggled with solid tumors and are associated with side effects that can require drugmakers to lower dosing. The company isn’t alone in that pursuit, as many startups as well as publicly traded companies are working on newer types of T cell engagers.
“What we want to achieve with the engager is to provide something in a biologic format which is very familiar to big pharma and has the ability to be scaled to be widely available to large numbers of patients,” Mount said.
The biotech’s lead program, dubbed “CYT X300,” has yet to enter human testing. Cytospire plans to test it in EGFR-positive solid tumors, such as colorectal, head and neck and non-small cell lung cancers.
Mount previously led Adaptate Biotherapeutics, another T cell engager developer, and oversaw R&D as chief scientific officer of GammaDelta Therapeutics, a cell therapy maker. Both Adaptate and GammaDelta were acquired by Takeda Pharmaceutical.
Mount has since joined Abingworth, which led Cytospire’s seed round, as a venture partner. (Abingworth is one of seven investors in Cytospire’s Series A round, which was led by 4BIO Capital and involved the venture arm of Servier Pharmaceuticals.)
“The Series A reflects two years of conviction building,” said Owen Smith, a partner at 4BIO. “We lead when we have conviction across a number of things, but the core things are technology, biology and team. Cytospire has all three.”
