An experimental stem cell therapy could help reverse corneal damage in people with a vision-threatening eye condition.
- Researchers
estimate that more than 10 million people worldwide live with corneal
blindness caused by disease or injury to the eye’s cornea.
- Unilateral
limbal stem cell deficiency (LSCD) is a type of corneal disease caused by
certain injuries that can lead to vision loss.
- A
new clinical trial is testing a potential new stem cell treatment for
LSCD.
- Researchers
reported that 50% of treated study participants experienced complete
cornea restoration after 3 months.
As of 2019, researchers estimate that more than 10 million people globally live
with corneal blindness due
to disease or injury to the eye’s cornea.
The cornea is the outermost clear layer on the front
of the eye. It is vital for clear vision, as it provides
Unilateral limbal stem cell deficiency (LSCD) is
a corneal disease that occurs when there is a shortage of the limbal stem cells that typically
regenerate the cornea as needed. This can lead to eye pain, blurred vision, and
even vision loss.
LSCD can be caused by corneal injuries, such as
Currently, treatments for LSCD include surgical
options, such as limbal stem cell transplants, as well as corneal scraping and amniotic membrane patching.
Ula Jurkunas, MD,
associate director of the Cornea Service at Mass Eye and Ear, and professor of
ophthalmology at Harvard Medical School, told Medical News Today that:
“Current treatment options
for limbal stem cell deficiency caused by cornea injuries have considerable limitations,
including injury to the healthy eye from removal of stem cells, or limited
effectiveness. Because of this deficiency, they are unable to undergo a cornea transplant, the current standard of
care, and they are often left blind in the affected eye and in great pain.”
Jurkunas is the principal investigator of a clinical
trial testing a potential new stem cell treatment for LSCD.
She is also the lead author of a study recently
published in the journal
Testing
novel CALEC stem cell therapy for eye damage
This clinical trial
revolved around an experimental stem cell therapy called cultivated autologous limbal epithelial cells (CALEC),
which had reportedly been developed by researchers in the Mass General Brigham
healthcare system.
“In the CALEC procedure, a very small biopsy is
performed in a patient’s healthy eye, which removes a small amount of limbal
cells,” Jurkunas explained. “Then, the cells are transported to a GMP (Good
Manufacturing Practices) facility at Dana-Farber Cancer Institute, where they
are expanded on a scaffold, a process that takes about two to three weeks.”
“The resulting stem cell graft is then brought back to
Mass Eye and Ear, where it is transplanted into the patient’s damaged eye,” she
continued. “After a brief recovery, the stem cell graft replenishes the limbal
stem cells and restores the cornea’s surface. At this point, a patient can
undergo a cornea transplant, or in the case of some patients in our study, do
not need further cornea treatment.”
“We felt it was important to find new options for our
patients that are safe to the donor and recipient eye, and effective,” Jurkunas
added. “We feel the CALEC procedure fills some of these current gaps, and our
study finds it was safe and feasible, and led to improvements in the cornea
surface.”
50% achieved
complete corneal restoration in 3 months
At the study’s
conclusion, researchers found the CALEC treatment completely restored the
cornea of 50% of the 15 study participants recruited for this clinical trial at
their 3-month follow-up.
Additionally,
their complete success rate increased to 79% at the 12-month mark and 77% by 18
months after treatment.
“These findings are significant because it shows that
CALEC’s effectiveness improved overtime, which can translate into a lasting
benefit for patients who undergo these treatments,” Jurkunas said.
Researchers also reported a high safety profile for
CALEC, with no serious issues occurring to either the donor or recipient eyes.
“Some existing methods to replenish limbal epithelial
cells do not have as high of a safety profile; for example risking the healthy
donor eye through the incision required to remove cells,” Jurkunas explained.
“CALEC, however, did have a high safety profile for
patients. Only one infection occurred, and that was not due to the CALEC
transplant itself. This is very important, because for a procedure to be widely
used, it needs to be a safe option for patients,” she emphasized.
As for the next steps of this clinical trial, Jurkunas
said they plan to expand to a phase 3 study of CALEC, that includes a
randomized design testing it against a different treatment:
“Additionally, we are
working to see [if] this stem cell transplant is feasible if it is allogenic
(from a separate donor), rather than autologous (from the patient’s healthy
eye). An allogenic approach may benefit patients who have sustained an injury,
like a chemical burn, in both eyes.”
‘Really
exciting’ findings according to eye experts
MNT had the opportunity to speak with Benjamin Bert, MD, a board-certified
ophthalmologist at MemorialCare Orange Coast Medical Center in Fountain Valley,
CA, about this study, who commented that any developments, especially in this
area of treating corneal disease, is very important and very exciting.
“The limbal
stem cells are cells that we are born with and then do not produce any
additional during our lifetime, so if there’s damage to those, it’s somewhat
irreversible,” Bert explained. “So the ability to repopulate those damaged
cells using our own cells is a really exciting idea.”
“Previously, the only way to fix this was with a
transplant from a cadaver donor,” he continued. “And there’s such a huge blood
supply to this particular part of the cornea that people had to be on full systemic immunosuppression, as if they had a
kidney transplant or a lung transplant, and we know that those medications have
major side effects. So being able to repopulate these damaged cells using our
own cells avoids all of those potential complications.”
For future research, Bert said he would like to see it
continue to progress, and see how feasible it would be on a larger scale.
“The description of how they’re able to culture these
cells requires pretty advanced technology, so it’s a question of can this be
expanded so that it can be offered to many patients, or is it going to be
limited just to these more academic centers where they have the laboratories
and the capabilities to do it,” he added.
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