Cord blood transplants help children fighting deadly diseases

Dr. Paul Szabolcs: Photo courtesy of UPMC

A simple blood stem cell transplant is showing tremendous promise in treating a wide range of metabolic, blood and immune disorders such as thalassemia and some leukodystrophies.

These are considered rare diseases – meaning there are fewer than 200,000 people with them in the US – so there is often little funding available to develop new therapies to help people suffering from them. So, researchers at UPMC Children’s Hospital of Pittsburgh set out to develop a therapy that could help several different disorders without having to craft individual approaches for each condition.

The team used blood stem cells from donated umbilical cords and placentas. In a news article, study senior author Dr. Paul Szabolcs, said they then used a combination of chemotherapy and immunotherapy to prepare the patients for the transplant and increase the chance of success.

“We approached the topic with the mindset to design a regimen that carefully balances low-intensity chemo (bringing safety) with sufficiently effective immunotherapy to blast away the patients’ immune system, therefore preventing rejection. Rejection has been a common failure when other centers explored the reduced-intensity conditioning (RIC) approach with cord blood. We are the first to prove the RIC is able to give reliable results in long-term engraftment.”

Szabolcs says another advantage to their approach was that it meant there didn’t need to be a perfect immune system match of donor and recipient.

“That’s huge for ethnic minorities. The probability of a perfect match is very low, but with a cord blood graft, we have a chance to overcome this discrepancy over the course of a couple months and then taper immunosuppressants away.”

Altogether 44 children were treated this way. After undergoing the preparation, they had the blood stem cells transfused into them and, once those cells had integrated into the body they got a second, smaller, transfusion a few weeks later to help kick start their immune system.

Most of the complications from the infusions were mild, and while around 5 percent of children died from viral infection due to the immune suppression this was much lower than in earlier studies. Another encouraging sign was that none of the children suffered severe Graft vs Host disease which can be fatal.

Thirty of the children in the trial suffered from metabolic disorders, meaning their bodies were unable to remove dangerous toxins, and this led to developmental delays in their brains. One year after the treatment all 30 children had normal enzyme levels and their neurological decline had stopped. Some of the children even showed improvements and gained new skills.

Most of the children with metabolic disorders had leukodystrophies. These are usually fatal within a few years of diagnosis. Even with a cord blood transplant the three-year survival rate is only 60 percent. In this trial more than 90 percent of children with leukodystrophies were alive after three years.

Dr. Szabolcs says this approach has a lot of advantages over existing approaches, including cost.

“There has been a lot of emphasis placed on cool new technologies that might address these diseases, but — even if they prove effective — those aren’t available to most centers. The regimen we developed is more robust, readily applicable and will remain significantly less expensive.”

The study was published in the journal Blood Advances.