By Michael Rytting and Sara Farris
Recently, the U.S. Food and Drug Administration (FDA) approved the use of Gleevec in combination with chemotherapy to treat newly diagnosed children with Philadelphia chromosome-positive acute lymphocytic leukemia (Ph+ ALL).
While this is good news, it comes more than 10 years after it was approved in adults and about 8 years after I treated my first pediatric patient with chemotherapy plus Gleevec followed by a stem cell transplant. This young patient came here from the Philippines with Ph+ ALL, and I was able to treat her 'off-label' since Gleevec had already been approved in adults and was well-tolerated. Today she is cured of cancer.
Historically, high-risk Ph+ ALL patients received chemotherapy and a stem cell transplant. However, in 2009, a study in the Journal of Clinical Oncology showed that the addition of Gleevec to chemotherapy increased the 3-year survival without relapse from 35% to 80.5%. In retrospect, perhaps my patient might not have needed the transplant (and its associated risks) to be cured of her cancer.
For the most part, this latest approval doesn't really change the therapy for children with this disease. In fact, we have already moved forward with enrolling patients on similar therapies in clinical trials that involve newer variations of Gleevec. The new drugs may be more effective or have fewer toxicities.
So what does this approval really mean for childhood cancer and drug development?
• For one, it confirms the positive impact Gleevec has on the treatment of Ph+ ALL in children.
• Also, from the studies conducted, it defines the best dosage for treating children.
• In addition, it may be beneficial to the pharmaceutical manufacturer, Novartis, by giving it an extension on its patent as a result of current legislation to incentivize companies to study therapies in children.
• It supports the benefit of having the Children's Oncology Group conduct a multi-institution trial bringing larger patients volumes and resulting in better, more comprehensive data.
• The results from the Gleevec pediatric clinical trials could potentially spare some kids from transplant.
Next steps to improve access to drugs
We need to partner with pharmaceutical companies and write trials that allow pediatric clinical trials to open after adult trials hit certain milestones and numbers. This could help speed up the time it takes from start to finish.
We have been able to initiate this model at MD Anderson, but it needs to occur on a more widespread basis. This could be aided by getting legislation enacted that would require pharmaceutical companies to build in a pediatric arm into their trials.
Financially, there isn't much incentive to try new drugs in children or rare cancers due to the smaller patient volume. Likewise, if anything goes wrong with a pediatric patient enrolled on trial, it could have far-reaching adverse effects on the progress and approval of the drug being researched. However, our pediatric patients have just as much right to these new agents as adults, and not decades afterwards.
Historically, there was a time when pediatric trials were pioneering treatments in adults - leukemia being a perfect example. We must look back and figure out how to regain this valuable role as pediatric oncologists in leading the development of new treatments for lymphoblastic leukemia patients.
It is interesting to see the FDA's approval of Gleevec. I hope there are many more approvals to come. In the meantime, we must continue to advocate for children with cancer and speed up their access to new agents
Michael Rytting, M.D., is an associate professor in MD Anderson's Division of Pediatrics. Sara Farris is a senior communications specialist in External Communications..