Trefoil Therapeutics CEO David Eveleth, Ph.D. is excited about the results of the Phase 2 study of its lead drug candidate, an engineered form of Fibroblast Growth Factor (FGF1) that stimulates corneal cell proliferation and migration and protects cells from stress and injury – all important attributes of one’s vision.
“We’re happy because the drug works. We demonstrated that it works,” he said.
Trefoil presented the results of its STORM study at the annual American Society of Cataract and Refractive Surgery meeting, held this year in Trefoil’s home city of San Diego the first weekend of May.
The STORM study looked at patients with corneal edema, swelling of the cornea, which Eveleth said is a “significant problem” for patients, especially for those with damage caused by conditions such as Fuchs dystrophy, which causes vision to worsen over the years and can lead to blindness without transplant surgery.
“That’s a pretty challenging surgery and it has a number of disadvantages,” he added.
Rather than removing and replacing an entire layer of cornea in a transplant procedure, subjects in the study had only a small section at the center of the cornea removed and then were treated with an injection of Trefoil’s FGF1 therapeutic, TTHX1114.
“In the absence of something to stimulate the process, those patients will heal very slowly. They will often not recover vision for two to three months after the surgery and some of them will never recover vision and will need a transplant,” Eveleth said, adding that the “exciting thing” about the study is that after being treated with TTHX1114, “those patients recovered their vision very quickly and all the associated markers indicate that the drug is working.”
‘Significant Unmet Medical Need’
Roughly 4% of the population over 40 years old will develop Fuchs. In the U.S. alone, there are about 50,000 corneal transplants performed each year for Fuchs and other corneal conditions.
The process used in Trefoil’s study of only stripping off the central part of the cornea used for vision means that many of those patients will be able to avoid transplant surgery in the future.
“Protection of the corneal endothelium in patients with Fuchs dystrophy undergoing surgery represents a significant unmet medical need,” said Mark Packer, M.D., chief medical officer of Trefoil Therapeutics. “There is now a promising therapeutic agent that speeds recovery of the endothelium following surgery. TTHX1114 provides hope that patients at risk of corneal decompensation may maintain good vision and avoid the risks of corneal transplantation.”
That unmet need is even more pronounced outside the U.S.
“In the United States, transplant surgery is not that big a deal – although this process has a lot of advantages over transplant – but outside the United States, transplant tissue is not often available. In many countries, you cannot get transplant material,” Eveleth said, adding that Trefoil expects number of patients worldwide to eventually be treated with TTHX1114 for Fuchs alone would be several times what the U.S. market is.”
In addition to treating more severe diseases like Fuchs, the STORM study also showed that TTHX1114 can also treat many types of corneal endothelial damage, such as complications that arise from ocular surgery, of which there are roughly 4.5 to 5 million performed in the U.S. each year. Eveleth estimates that 5 to 10% of those patients would benefit from TTHX1114 to heal from surgery more quickly.
In addition to developing TTHX1114 as an injection to treat various conditions that lead to corneal edema. Trefoil is also developing the compound as an eye drop to reduce the duration and impact of ocular herpes virus related ulcers and other corneal ulcers.
An estimated 500,000 patients annually suffer corneal complications of herpes virus reactivation in the U.S. Globally, 10 % of all blindness – 4 million people – is attributable to herpes infections. There are currently no treatments that directly address corneal ulcers related to herpes infection.
In addition to herpes, corneal ulcers can arise from a variety of other diseases or from injury. TTHX1114 has also shown potential in addressing chemical injury in studies supported by a grant from the U.S. Department of Defense.
For the injectable TTHX1114 product, the next phase is to “show in a clinical trial the drug has an effect on corneal edema that is due to multiple causes,” Eveleth said, adding that those additional trials could take several years to complete and file with FDA and that TTHX1114 could be a marketable product by the end of 2028.
CEO: David Eveleth, Ph.D.
Headquarters: San Diego, Sorrento Valley
Business: Clinical-stage biotechnology company leveraging its engineered FGF-1 protein technology platform to develop pharmacologic treatments for serious corneal endothelial diseases and epithelial disorders.
Notable: Trefoil’s FGF1 compound could replace many cornea transplant surgeries.