Children with life-threatening conditions, such as cancer, are often candidates for clinical trials. What are they? Which factors should parents weigh in determining whether enrolling in one is a good option for their child? Dr. Steven DuBois, director of the Advancing Childhood Cancer Therapies Clinic at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, answers questions about clinical trials.
What are clinical trials? Why are they important?
Clinical trials are systematic, scientific investigations of new drugs or therapies for a specific disease. Through clinical trials, we have taken many fatal pediatric cancers and turned them into diseases that now have cure rates of over 90 percent. Although we still want to improve those cure rates, research is now increasingly focused on making treatments more tolerable and reducing late effects of therapy.
In other pediatric cancers, we are not doing as well, so our goal is to improve cure rates for patients with a poor prognosis. After decades of focusing on various chemotherapy agents and combinations to improve outcomes, much of today’s focus is on precision medicine, immunotherapies and other novel approaches that we hope will deliver less toxic and more effective treatment than chemotherapy.
What is a Phase 1 trial? Phase 2? Phase 3?
When we hear about a new drug or combination that has not yet been tested in children but shows promise in laboratory research or adult trials, we must first determine the best dose to use in children. What are the side effects? How is it absorbed into the blood? These are the goals of a Phase 1 trial. Because we do not yet know the best pediatric dose, let alone efficacy of the drug in children, patients are usually only candidates for Phase 1 trials if their cancer has not responded to standard therapy.
Once a pediatric dose is established, we move to a Phase 2 trial. Here the aim is to study a similar group of patients treated with the same dose of the medicine and determine how likely their cancers are to respond to the new therapy. These patients usually also have relapsed or treatment-resistant cancers.
If Phase 2 produces promising results, we then move into a Phase 3 trial for newly diagnosed patients to see if adding the new drug or adjusting the regimen upfront cures more patients and/or reduces toxicity. This is usually a large, randomized trial. A successful Phase 3 trial can help establish a new standard of care and is often the final step before a new therapy can be approved by the federal Food and Drug Administration.
How do you present Phase 1 and Phase 2 trials to parents? What are some of their questions and concerns?
This can be a difficult and very personal decision and a difficult conversation. We make sure parents understand the purposes of Phase 1 and Phase 2 clinical trials and their potential risks and benefits. We explain the potential benefit to the child in terms of reducing the size of their tumor, stopping it from growing, reducing its symptoms or extending life. We are careful not to raise false hopes and explain that even though we try to predict which patients are most likely to benefit, the probability of a response, unfortunately, is often low. We also make sure families understand the option of not enrolling in an early phase trial and discuss the role palliative care can play in easing their child’s symptoms.
Quality of life concerns often come into play, so we also talk about the extra appointments, extra blood draws and extra hospitalizations that might be needed. Parents understand that we are a leading pediatric cancer center with a broad portfolio of clinical trials, but they also want to know what might be available elsewhere, so that enters our conversations, too.
How do you present Phase 3 trials to parents? What are some of their questions and concerns?
Talking with families whose child might be a candidate for a Phase 3 trial is completely different. Families whose children are candidates for early phase trials are already savvy about cancer and cancer therapies. Phase 3 trials, on the other hand, usually enroll newly diagnosed patients.
Our first task is to make sure parents understand their child’s diagnosis and the standard of care. Only then do we introduce the option of a Phase 3 clinical trial. We explain that it is a randomized trial, with children assigned to one arm of the trial receiving the standard of care and children assigned to the experimental arm receiving some modification of standard care. We explain what we are trying to learn and explain that, over the previous 5-10 years, the experimental therapy has demonstrated promising outcomes in Phase 1 and Phase 2 trials for patients with relapsed or treatment-resistant disease. Now we want to learn if this experimental therapy should become the new upfront therapy to lessen the chances of relapse and/or achieve cure with less toxicity.
We also explain that these trials are monitored by an independent group. If, at any point, it looks like the experimental treatment is making things worse, the trial is stopped. Likewise, if it looks like the new medicine is clearly better than the standard regimen, then the trial is also stopped early and everyone then usually gets access to the new medicine.
What is the bottom line?
Whatever the phase of the clinical trial, our job is to provide families with the information they need to make an informed decision about their child’s care and, once they have made a decision, to provide them with the physician, nursing and psycho-social support they need to see them through this difficult time.