Skin stem cell therapy helped prevent new wounds in RDEB

Mesenchymal stem cell treatment also healed wounds faster, analysis shows

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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People with recessive dystrophic epidermolysis bullosa (RDEB) developed fewer new wounds after getting treatment with skin-derived mesenchymal stem cells, a new clinical trial analysis shows.

The treatment also led to newly developed wounds healing more quickly, and healed wounds more frequently remained closed.

The study, “Kinetics of Wound Development and Healing Suggests a Skin-Stabilizing Effect of Allogeneic ABCB5+ Mesenchymal Stromal Cell Treatment in Recessive Dystrophic Epidermolysis Bullosa,” was published in Cells.

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Mesenchymal stromal cells (MSCs), also called mesenchymal stem cells, are precursor cells that have the ability to differentiate into various cell types. Because these cells can travel to damaged tissues and boost tissue regeneration, they may be a promising approach to promote wound healing in people with RDEB.

A particular kind of skin-derived MSCs, carrying a protein marker called ABCB5, have been deemed better than other MSCs at promoting tissue regeneration. These are being investigated as a potential treatment to help heal wounds in RDEB.

Rheacell, the company developing this strategy, sponsored an open-label clinical trial (NCT03529877) in which people with RDEB were given three infusions of ABCB5-positive MSCs over the course of about a month and were monitored for 12 weeks.

The study’s main goal was to assess how well the stem cell treatment could promote healing for wounds that were present at baseline (before the start of the trial). Results, published earlier this year, showed these wounds healed faster than would be expected without treatment.

RDEB treatment goals

While healing existing wounds is a major goal of RDEB treatment, it isn’t the only goal — ideally, a maintenance therapy for RDEB also would be able to reduce the development of new wounds, or at least cause new wounds to resolve more quickly without becoming serious.

Here, a team led by scientists at Rheacell analyzed photos of participants taken during the open-label trial in order to assess how treatment with ABCB5-positive MSCs affected the development of new wounds. This was a post hoc analysis, meaning the study was designed and carried out after the trial was complete and all the data had been collected.

The analysis included data for 14 people with RDEB, ages 6 to 36. A total of 174 wounds that were not present at baseline were identified from the photographs. Among these new wounds, 77 developed within the first 17 days of the study, before the second injection, and another 48 developed over the following 18 days, before the third injection. The remaining 49 wounds were seen only at the last study visit at week 12.

Put another way, patients developed a total of 125 new wounds in the first month or so of the study, when the MSC infusions were being administered. But then, over the next two months, only 49 new wounds were observed. The reduced occurrence of wounds following repeated infusions “suggest a therapeutic advantage of repeated dosing,” the researchers wrote, noting that this will be an important consideration for future studies.

Among the 77 wounds that occurred in the first weeks of the study, more than half had closed by the next available assessment about 2.5 weeks later, and most of these remained closed over the remaining follow-up. Similarly, of the 48 wounds seen between study days 17 and 35, three-quarters were healed by the assessment at week 12.

Faster wound healing

Comparisons against baseline wounds that appeared before treatment suggested that, after starting on ABCB5-positive MSCs, new wounds tended to heal at much faster rates. Collectively, the data suggest “a systemic healing-promoting and skin-stabilizing effect of treatment” with this stem cell therapy.

The researchers stressed that this post hoc analysis was done using unstandardized photographs, and the study did not include a control group. As such, more research will be required to verify these results and further test the potential of ABCB5-positive MSCs in RDEB.