Biotechnology and Pharmaceuticals · global
Claris Raises $118 Million to Advance Late-Stage Trial in Rare Corneal Disease
CSB-001 will move from a once-targeted indication into a pivotal trial involving about 400 people; new funding and a commercial team are in place, but key efficacy data have yet to undergo public scrutiny.
Once the stem cells on the corneal surface are depleted, the eye may gradually lose its ability to repair its transparent window. U.S. biotech company Claris Biotherapeutics has now raised $118 million (approximately NT$3.5 billion) for this disease, which has few treatment options, as it prepares to advance the CSB-001 eye drops into late-stage clinical trials.
The Series B financing was co-led by Samsara BioCapital and Catalio Capital Management, with participation from new and existing investors including Sofinnova Investments and Novo Holdings. The funds will be used to complete a proof-of-concept study and a natural history study in limbal stem cell deficiency (LSCD), and to support pivotal trials expected to begin in the first half of 2027 as well as pre-launch preparations.
In patients with LSCD, the stem cells responsible for renewing the corneal surface are damaged or lost, potentially causing persistent epithelial defects, inflammation, fibrosis, and vision loss. Surgical procedures such as stem cell transplantation may currently be considered for severe cases, but their applicability and accessibility are limited. Claris says at least 30,000 patients in the United States are receiving ophthalmic care, although this estimate has not yet been sufficiently confirmed by independent epidemiological data.
CSB-001 is an ophthalmic solution containing recombinant human deleted hepatocyte growth factor, dHGF, designed to promote corneal epithelial regeneration while modulating inflammation and fibrosis. It was previously developed to treat neurotrophic keratitis, but according to industry media reports, the indication did not achieve the expected results. The company shifted its development focus to LSCD after researchers observed improved vision in some patients who also had LSCD.
The ongoing proof-of-concept study has an open-label design and has enrolled 63 participants. Some patients first undergo 20 weeks of observation, followed by 20 weeks of treatment with CSB-001 eye drops. Claris expects to report results in the second half of 2026 and says the data to date show improved vision. However, complete figures, the duration of response, and safety details have not yet been disclosed, and open-label studies are also more susceptible to the effects of the natural course of disease and observational bias.
If the early results are sufficient to support the next step, the company plans to conduct two pivotal trials involving approximately 400 people in total, using a vehicle without an active ingredient as the control. The primary efficacy endpoint will be vision, supported by corneal anatomical measures. This will be critical to determining whether CSB-001 can truly replace or delay surgery, and will also test whether the improvement in vision is clinically meaningful and reproducible.
Claris has also restructured its leadership team, appointing Stephen Brady as president and CEO, Brian Baum, who was involved in the commercialization of the neurotrophic keratitis drug Oxervate, as chief commercial officer, and Abivax CEO Marc de Garidel as chairman. The scale of the financing and the arrival of commercial talent indicate that the company has begun preparing for late-stage development and an eventual launch. But until the complete proof-of-concept results are available, this remains a high-risk bet based on preliminary signals.