Researchers at the Medical University of South Carolina are testing a possible treatment for multisystem inflammatory syndrome, MIS-C, a rare but serious complication of COVID-19 in children. The syndrome can cause inflammation in the heart, lungs, kidneys, brain, skin, eyes and gastrointestinal organs. One MUSC Health pediatrician described MIS-C as an immune response to the virus “gone haywire.”
The syndrome has only affected seven children in South Carolina since the start of the pandemic. All have recovered. But MIS-C is blamed for killing children in other states, including Louisiana and Colorado.
In the clinical trial at MUSC, children with MIS-C who meet certain criteria will get an IV treatment called remestemcel-L, which goes by the brand name Ryonicil. It uses cells from the bone marrow of healthy people, mesenchymal stromal cells, that have been expanded in a lab to try to help sick people. The hope is that they’ll help kids with MIS-C by getting their over-active immune systems under control and repairing some of the damage the syndrome has caused.
Allison Eckard, M.D., a pediatric infectious disease specialist at MUSC Children’s Health and an associate professor in the College of Medicine, is helping lead MUSC’s part of the trial. “The safety profile looks very safe, with very few side effects or concerns. As a parent, I would 100% want to give this to my child because it may improve outcomes and there’s very little downside of giving it,” she said.
The treatment was actually developed by the company Mesoblast for another purpose: to try to help people who have had bone marrow transplants by keeping their bodies from rejecting the transplanted tissue. Eckard said it’s also a potential MIS-C fighter because, like the body’s reaction to a bone marrow transplant, MIS-C is a harmful immune system reaction to a perceived enemy.
Research suggests remestemcel-L is safe for children, one of the important thresholds in clinical research. A very small study indicates it may also be effective in the fight against COVID. Twelve adults with COVID who were on ventilators because their immune systems were overreacting to the infection, causing acute respiratory distress syndrome, were given the treatment. Eckard said it seemed to help. “They had a much higher survival rate than people who didn’t receive the product. This is preliminary data, but it looks like it could work.”
To qualify for the MUSC trial, a child’s MIS-C must be causing heart trouble and affecting at least one other organ. The kids also have to be 17 or younger and have either tested positive for COVID-19 or been exposed to the coronavirus within a few weeks of showing MIS-C symptoms.
The current treatment for MIS-C is similar to how doctors care for kids with a condition called Kawasaki disease. “The standard of care normally is to give large amounts of very non-specific anti-inflammatory drugs – steroids, immunoglobulin,” Eckard said.
“But I think the advantage of the treatment we’re testing is that it’s a more specific, really focusing just on the tissues that are more affected – the blood vessels, the heart and the lungs rather than just everything. Because there are side effects of steroids. We find them very safe, we give them all the time, but this may be advantageous because it’s more directed toward the damaged tissue,” Eckard said.
She’s pleased that the trial is in a category called expanded access, which means everyone in the trial gets the treatment. Nobody gets a placebo. “Being able to give this in addition to standard of care is huge because then it’s not as hard to decide if the child should be in the study or not.”
The remestemcel-L trial is one of several studies underway at MUSC focusing on COVID-19, including one testing a possible antibody treatment. Eckard is pleased to see that growing list include potential options for kids. “Hopefully, we won’t see many children with MIS-C, but you want to have good treatments for them.”