Stem Cell/Gene Therapy combo heals patients battling rare disorder

Brenden Whittaker and his dog: Photo by Colin McGuire

A few years ago, Brenden Whittaker was running out of time. Brenden was born with a rare condition called x-linked chronic granulomatous disease or XCGD. It meant he lacked a critical part of his immune system that protects against bacterial or fungal infections.

Over 22 years Brenden was in and out of the hospital hundreds of times. Twice he almost died. When antibiotics failed to clear up persistent infections surgeons had to remove parts of his lungs and liver.

Brenden felt he was running out of options. Then he signed up for a clinical trial (funded by CIRM) that would use his own stem cells to correct the problem. More than four years later Brenden is doing just fine.

And he’s not the only one. A new study, published in the journal Nature Medicine, shows that six other patients in the clinical trial are now in remission and have stopped taking any other medications.

Dr. Don Kohn: Photo courtesy UCLA

Don Kohn, the lead researcher on the team from UCLA’s Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, says that in the past the only “cure” for people with CGD was a bone marrow transplant, but that was rarely an option for most patients. In a news release he said finding a perfect match for a transplant was difficult, and even then, patients had to take powerful anti-rejection medications to stop their body rejecting the transplant. So, they developed another approach, using genetically re-engineered stem cells from the patient themselves.

“With this gene therapy, you can use a patient’s own stem cells instead of donor cells for a transplant. This means the cells are perfectly matched to the patient and it should be a much safer transplant, without the risks of rejection.”

The team removed blood stem cells from the patients and, in the lab, corrected the genetic mutation that caused CGD. They then returned those cells to the patients which, because they are stem cells, multiplied and created a new blood supply – one free of CGD – and repaired the immune system.

Brenden was the first of five patients treated in the US. Another four were treated in Europe. All were between the ages of 2 and 27 (CGD patients often die in their 20’s because of the impact of repeated infections).

  • Two patients died because of previously incurred infections
  • Six of the seven surviving patients have discontinued previous treatments
  • Four new patients have since been treated and are currently free of infections

Dr. Kohn said the results are really encouraging: “None of the patients had complications that you might normally see from donor cells and the results were as good as you’d get from a donor transplant — or better.”

The next step is for the researchers to work with the US Food and Drug Administration to get permission to carry out a larger trial, with the eventual goal of getting approval to make it available to all patients who need it.  

Regular readers of our blog will remember that Don Kohn also pioneered a similar approach in treating, and curing, children battling another rare immune disorder, severe combined immunodeficiency or SCID. You can read about that here.

As for Brenden, he is now in college and has his sights set on medical school. In 2016 we profiled him in our Annual Report and ran a long interview with him on the blog where he talked about the joys of mowing the lawn and learning to live without a deadly disease stalking him.

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