
Novartis backs Harvard spinout's quest to build TCR repository in $48M round
As T cell receptors emerged as a potent tool for the immune system to latch onto tumor antigens, Stephen Elledge wanted to screen antigen-TCR matches in a faster, more systematic way — one that would go beyond currently known targets but stop short of the new realms of neoantigens bioinformatic predictions.

So the Harvard professor spent the last 7 years consolidating new tech to come up with a platform that can run multiple TCRs against antigen epitopes and pinpoint the exact pairs that appear to interact. There’s also a built-in library of the human peptidome to flag any off-target effects and prevent safety scares down the road.
What started out on 96 plates in Elledge’s lab has now been scaled up and spun out to TScan Therapeutics, which is now making its first public appearance with $48 million in total Series A and B funding.
The interest from Novartis Institutes for BioMedical Research was a key impetus for the round, CEO David Southwell told me. The pharma giant’s venture arm also joined alongside Bessemer, GV and Longwood Fund.
“The whole goal is sort of to do it differently than the way everyone else is doing it,” he said, which also explained why he jumped on board last October after merging Inotek with Rocket.
One of Elledge’s big breakthroughs here, Southwell said, is developing a unique fluorescent detector system to find the proverbial needle in the haystack.
“It’s long been known as what happens when a cytotoxic T cell meets an antigen is that it puts out compounds like perforin, which put holes in the tumor cells, and granzyme B, which is a messenger that is essentially a cytokine which tells a cell to die. So that’s been known,” he said. “The question is how do you actually measure the actual killing activity between the cytotoxic T cell and a target?”
The ability to sort that all out on the fly means TScan can run a high-throughput, whole-genome search for novel antigens and the T cell receptors that may target them.
There are many paths to go down with a platform as broad as this, and Southwell readily admits he’s yet to make up his mind as to whether TScan will opt for platform licensing or keep more of the development programs to itself. But the money they have is more than enough for a team of 20 scientists — many scooped from prominent biotechs like Editas, CRISPR, KSQ and Juno — doing discovery work.
The platform “is so broad that we could do a number of pharma partnerships that are different in their scope, they don’t compete with each other, and they leave us open to develop what we want, which is a repository of TCR antigen pairs that work in both solid and liquid tumors,” he said.
Before arriving at that allogeneic future, though, TScan has a tight timeline to execute on autologous projects. The goal is to have two lead candidates within 6 to 9 months and go into 2021 with a couple of INDs.
Much of that will be conducted in a new site at Waltham, Massachusetts, which will offer a key component that their current digs at Harvard Medical School lack: GMP manufacturing facilities.
“One of the biggest mistakes that cell therapy companies make is having a platform like this and then you find a lead, and you’re really excited about your lead, and you haven’t figured out how to manufacture it,” he said.
He’s recruited Ken LeClair out of Editas to run that operation. Gavin MacBeath, a scientific founder of Merrimack, is CSO; Amgen vet Henry Rath is handling all the pharma interest as CBO; and Robert Crane is CFO.