By Raffaele Pereno – PhD, MBA
LISBON, Portugal – During a meeting with Dr. Ross Macdonald, Chief Commercial Officer of StemSight, at BioEurope Spring, the discussion focused on a fundamental limitation in current treatments for limbal stem cell deficiency (LSCD) and how emerging cell therapy approaches may overcome it.
LSCD occurs when limbal stem cells, located at the edge of the cornea, are depleted. These cells are essential for maintaining corneal integrity through continuous regeneration, lubrication, and protection. When they are lost due to injury, chronic inflammation, or prolonged contact lens misuse, the cornea progressively deteriorates, resulting in inflammation, opacity, and ultimately vision loss.
A Disease with Limited Options
LSCD is a rare disease and will likely receive orphan designation in relevant jurisdictions such as the U.S. and EU. Over half of cases are bilateral, meaning both eyes are affected. Severe forms—particularly bilateral cases—are relatively uncommon and behave clinically like orphan conditions.
Today, treatment options remain limited. The most advanced therapy available, Holoclar—developed by Holostem Terapie Avanzate (initially in collaboration with Chiesi Farmaceutici)—is based on autologous transplantation of limbal stem cells. However, as highlighted during the discussion, this approach presents several key constraints.
“You need a healthy eye to treat the diseased one,” Macdonald told CheckOrphan. “If both eyes are affected, which is the case for a significant proportion of patients, there is no available treatment.” It is estimated that up to 60% of LSCD patients fall into this category.
In addition, autologous approaches yield limited quantities of limbal stem cells, potentially requiring repeated administrations to maintain the stem cell population—and, consequently, the corneal epithelial cells derived from them—over time.
StemSight’s Approach: Reprogramming and Redefining the Cell
StemSight, a spin-off from Tampere University, is developing an alternative approach based on induced pluripotent stem cells (iPSCs).
The company has focused on defining what constitutes a true limbal stem cell using gene expression and biomarker profiling. This work has enabled StemSight to develop a proprietary differentiation process, starting with iPSCs reprogrammed from adult somatic cells and yielding a limbal stem cell–like population.
Its lead product, STE-101, is an allogeneic, hypoimmune, iPSC-derived limbal stem cell therapy targeting LSCD.
“Our goal is not just to replace cells, but to recreate a functional limbal stem cell population that can both self-renew and regenerate healthy corneal epithelium, ultimately delivering a curative outcome for patients,” Macdonald noted.
A Potential Shift Toward Allogeneic Therapies
A key aspect of StemSight’s strategy is its allogeneic model. By moving away from patient-specific cell harvesting, the company aims to:
- enable treatment of bilateral disease
- standardize manufacturing
- create a scalable, cost-effective, off-the-shelf therapy
This contrasts with current approaches, where manufacturing is individualized, expensive, and difficult to scale.
At the same time, StemSight’s approach may address another limitation of existing therapies: durability. Because many current treatments involve variable quantities of limbal stem cells, repeated dosing may be required. By generating cells that more closely resemble a true stem cell phenotype, StemSight aims to improve long-term engraftment and function.
“The field of iPSC research is maturing,” Macdonald stated. “We are seeing strong clinical progress in areas such as Parkinson’s disease and cardiac indications, and regulators are becoming increasingly familiar with these approaches.”
“We have had very constructive interactions with regulatory agencies, which have helped us map a clear path toward clinical development.”
StemSight is currently working toward entering clinical development, with initial timelines targeting 2028.
For more information please contact:
Dr. Ross Macdonald