T-cell immunotherapy trials are showing potential to transform care for some childhood cancers.
Over the last several years, immunotherapy has emerged as a promising alternative to traditional forms of cancer treatment. Seattle Children's Hospital is at the forefront of these efforts, with several trials underway to better treat leukemia in children and young adults by boosting the immune system with T-cell immunotherapy. Researchers hope T-cell therapy will transform care for some childhood cancers, making treatment more effective, in less time and with milder side effects.
Here's how it works: T cells, which are white blood cells in the immune system that fight infection, are collected from the child's blood. Then, using laboratory techniques, the T cells are reprogrammed to recognize cancer cells and grown into millions of reprogrammed T cells, known as CAR (Chimeric Antigen Receptor) T cells. The CAR T cells are returned to the child's body, where they seek out and destroy cancer cells without harming normal, healthy cells.
Early results from the ongoing trials at Seattle Children's are promising:
- 40 of 43 patients treated in one leukemia clinical trial achieved complete initial remission
- The 93 percent remission rate was confirmed by highly sensitive tests designed to detect tiny amounts of cancer cells
- 40 patients who achieved complete remission included children with very high tumor burdens, as well as children who were diagnosed with acute lymphoblastic leukemia (ALL) as infants. When they started the clinical trial, the patients had less than a 20 percent chance of survival using current treatments.
- Of the patients who achieved initial remission, about half are still in remission one year after therapy. Some are still in remission more than three years after therapy.
Children's Hospitals Today caught up with Michael Jensen, M.D., director of the Ben Towne Center for Childhood Cancer Research at Seattle Children's, to gather his perspectives on the future of immunotherapy treatment for pediatric cancers.
What does the early success of T-cell immunotherapy trials represent for the future of pediatric cancer treatment?
One of the benefits is that it appears to work when all other therapies stop working. However, our goal is not to have this be a rescue therapy for children after they've gone through years of chemotherapy, radiation, surgery and bone marrow transplants. Our goal is to understand if this therapy can be effectively used earlier in a patient's treatment so he or she won't need highly toxic, debilitating therapies in the future.
It would represent a paradigm shift in how kids can be cured. This therapy requires only one dose and tends to put patients into remission in less than two weeks. They only need one dose of therapy and within two weeks they're back at school and on the soccer fields instead of going through three years of chemotherapy and all the issues that are related to that.
What are the primary challenges you face to get to that point?
There are still some barriers to making CAR T cells work well against solid tumors. But I'm optimistic we are making progress towards unlocking the potential of this therapy for all types of cancers. The most significant obstacle to being successful isn't the science; it's the insufficient funding from the federal government for pediatric cancer research to do this work.
What are the keys to overcoming those funding challenges?
Thankfully, research to help children tends to be a collaborative enterprise. At Seattle Children's, we're forming an organization called CureWorks. This is an enterprise that facilitates the participation of children's hospitals in CAR T-cell trials even if they don't have a GMP facility (Good Manufacturing Practice, as required by the FDA for production of CAR T cells) at their site.
We need to figure out how to democratize this therapy. That's what the CureWorks network is seeking to achieve. Children's hospitals can join this partnership, and their patients can benefit from these trials at their sites. The major programs that can make these cells would make them for the other hospitals. The patients get to stay in their local communities and the parents get to continue working.
How rewarding is it to be a part of this?
It is a privilege to be doing this work on behalf of children, their parents and their families. I think that is true of all my colleagues in this field. They are impassioned by the potential to change the future for children that are diagnosed with cancer. At the same time, we have to be careful to manage expectations. We don't want to tell our communities that we have something that's perfect and it works every time. That's not the case. We have a lot of work to do.
That's why we need support. We need to figure it out as a community that cares about children and cancer and wants to see this reach its fruition. But the successes we do have are very symbolic. They are very meaningful for families and parents—there's hope. In Seattle and in similar research programs around the country, there are people every day doing the hard work necessary to make cures available for the children that will be diagnosed tomorrow.
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