Right now, the only way to prevent blindness in patients with a group of genetic eye disorders called corneal dystrophies is with cornea transplant surgery. But Trefoil Therapeutics is looking to change that: It's raised $28 million to push its regenerative treatment toward the clinic.
Trefoil’s first goal is to bring its drug, dubbed TTHX1114, to patients with endothelial corneal dystrophies, which affect the cells lining the back of the cornea. The San Diego-based company is testing its drug in multiple forms of the disorder, including Fuch’s dystrophy, which is caused by the gradual deterioration of cells in the cornea’s endothelium.
“There are no alternatives to surgery for these patients—they go blind if they do not get surgery. Our goal is to be able to treat them with a drug, without surgery,” Trefoil CEO David Eveleth, Ph.D., told FierceBiotech.
TTHX1114 is an engineered form of the fibroblast growth factor-1 protein designed to reverse vision loss by making the cornea regenerate the endothelial cells that are dying off. To reach the back of the cornea, it is injected into the eye, but Trefoil is also working on a topical version for epithelial conditions, which affect the cells that line the front of the cornea.
“Corneal endothelial dystrophy is fundamentally a disease of the failure and degeneration of the endothelial layer in the cornea,” Eveleth said. “This drug causes those cells to proliferate and regenerate … That’s the basis of the therapeutic effect: rather than having to transplant new cells in [via surgery], we can cause patients’ own cells to regenerate.”
The cornea may be among the smallest organs to transplant, but it’s still a solid organ transplant. That means patients are at risk of their body rejecting their new cornea and must take lifelong immunosuppressive drugs. And in some parts of the world, there just isn’t enough transplantable corneal tissue to go around.
“Many patients outside the U.S. and Europe don’t even have the option of surgery,” Eveleth said.
The series A proceeds will support a proof-of-concept phase 2a study of TTHX1114 in multiple corneal endothelial dystrophies. It has posted positive results in preclinical studies, clearing the buildup of material that clouds the cornea in animal models and boosting the proliferation and migration of endothelial tissue in both healthy and diseased corneas. Trefoil plans to start clinical trials in 2020 and will follow that up with an IND for the topical version in 2021.
Bios Partners led the financing, with Access Biotechnology, Aju IB Investment, Correlation Ventures, ExSight Ventures, Hatteras Venture Partners and InFocus Capital Partners pitching in.