Can new drugs punch holes in cancer's protective barrier? For Parthenon Therapeutics, that's the $65M question
Imagine taking an ice pick to the protective barrier that surrounds cancer cells. That’s essentially what Parthenon Therapeutics is trying to do — and now a handful of investors including Pfizer’s venture arm are putting up $65 million to see it through.
“For at least 50% of tumors out there, cancer therapies or cancer fighting cells are unable to penetrate the tumor because of a physical barrier,” CEO Laurent Audoly told Endpoints News. “When we did our research, we quickly realized that this was a wide open opportunity.”
Audoly, the former CEO of Kymera, launched Parthenon in the summer of 2019 to find new ways of reprogramming the tumor microenvironment to attack cancer cells’ protective shields. And Wednesday, he and his team unveiled a sizable Series A round led by Northpond Ventures, Pfizer Ventures and Taiho Ventures.
Research suggests there are several types of barriers that underpin immune cell exclusion, Audoly explained. Most companies are pursuing ways around a concept that scientists have dubbed “dynamic barriers,” or immunology-based barriers which prevent the body’s immune system from destroying the tumor. A large crowd of immuno-oncology companies big and small fall under this umbrella, with the number of drugs in the clinic swelling over the last few years. In the case of Merck and its blockbuster Keytruda, for example, PD-1 is a type of dynamic barrier, according to Audoly.
Then there are functional barriers, in which the core of the tumor generates repellents against immune cells that could destroy the tumor. There’s also what’s called a physical or mechanical barrier, which Audoly says is akin to barbed wire built around the core of a tumor, which prevents immune cells and some antitumor agents from penetrating the cells. This is the type of barrier that Parthenon is most focused on, in addition to functional barriers.
Their approach is simple: “Think of it as, for example, an icebreaker that is making its way across the ice sheets. And then behind that, there are a number of ships with their precious cargo that can then reach the destination,” Audoly said.
On Wednesday, some of Parthenon’s collaborators published a piece in Nature describing one of the company’s approaches with its lead program PRTH-101 — neutralizing discoidin domain receptor 1 (DDR1), a collagen receptor that’s believed to play a role in stabilizing the tumor extracellular matrix. Researchers showed in preclinical models that by neutralizing DDR1, they could perforate the tumor’s protective barrier in triple negative breast cancer.
“That is not the only type of tumor… that we’re going to go after,” Audoly said. “We believe that there are many other opportunities besides this one cancer type for our pipeline.”
The chief executive wasn’t ready to offer a timeline on the company’s path toward the clinic, but said the Series A funds will be used to grow the 10-person team and scale the platform. In a year from now, he expects to have 25 to 30 staffers.
“We were a company that was really founded into so-called wilderness,” he said. “We’re founders that came together because of our strong belief that there are opportunities for patients living with cancers that are basically not being advanced into the clinic.”
What’s next? Audoly and his team will keep chipping away at the pipeline, one chunk at a time.