Phase I clinical trials are the foundation for how we develop new
cancer drugs. Typically, they involve only several dozen patients and
study a new medicine’s effect on a variety of cancer types.
David S. Hong, M.D., sat down with us to explain
more about Phase I clinical trials and answer some of patients’ most
frequently asked questions.
What is a Phase I clinical trial?
Phase I clinical trials are the first time human
beings are being treated with an experimental drug. It starts with
researchers figuring out a pathway to kill cancer. A drug company then
develops a medication that mimics that process. The primary purpose of
a Phase I is to figure out how much of the drug we can safely give
patients and see a benefit.
But that’s not the only purpose. Phase I trials also help us figure
out which cancers benefit from these drugs.
Who should consider participating in a Phase I clinical trial?
Phase I clinical trials aren’t for everyone. Most patients who
choose Phase I clinical trials are running out of options. Typically,
they have metastatic disease, haven’t had success with standard chemotherapy, have mild or no symptoms and don’t
want to go to hospice. They’re willing to see if they can help others,
and possibly themselves, by participating in a Phase I clinical trial.
What questions do you hear most from patients considering
Phase I clinical trials?
“Is there a placebo?” Unlike Phase III clinical trials, there’s usually not a
placebo in a Phase I trial. Everyone gets the drug, just at different
There are also a lot of questions about schedules. Phase I clinical
trials are very intensive and require multiple visits from the
patient. Since it’s the first time this drug has been used in human
beings, we’re very vigilant.
We also get a lot of questions about side effects. Typical side
effects include nausea, vomiting and diarrhea. But side effects
are different for each patient in each trial. We try to give patients
an overview of the most common side effects, those that are most
concerning and then all possible side effects. Most side effects are
reversible and treatable. We either stop the drug or we give another
medication to address the side effects.
How long will a patient be enrolled in a Phase I clinical trial?
Patients can usually stay on a Phase I clinical trial as long as
they benefit. A traditional Phase I clinical trial lasts about two
years (from the time we start enrolling to the time that we actually
close out a study).
What happens if a patient’s condition doesn’t improve?
If a patient’s clinical condition declines, it may just be because
of side effects and we can address those issues. Or, it’s because the
tumors are growing. We re-image patients on a regular basis, and we do
measurements on the patient following a preset criteria. Depending on
the drug and the set criteria, we’ll take the patient off the study if
a tumor grows a certain percentage. What happens next depends on how
the patient is doing overall. Many patients go on to another Phase I
study or back to their medical oncologist because he or she has one
more therapy to try. Or, if they are out of options, they may decide
to go to hospice.
What are some of the most promising Phase I clinical trials we
have at MD Anderson right now?
There’s lots of exciting research happening. In a Phase I trial of the drug LOXO-101, we’ve seen
tumors shrink in patients with cancers that are linked to the gene
fusion of NTRK. We’ve also seen promising results in a Phase I trial of a combination of inhibitor
drugs that target a cancer cell’s signaling. Lastly, we have many
immunotherapy Phase I clinical trials, but one
that’s exciting is the upcoming MAGE-A10 study on the use of
engineered cells of the immune system (called CAR-T cell and T-cell
What advice do you have for caregivers of patients enrolling
in Phase I trials?
My number one piece of advice is don’t push your loved one to do a
Phase I. It’s not always the best choice for the patient.
Two, be prepared to support this patient timewise. It’s an intensive
and time-consuming process.
Three, ask questions. You need to be informed.
Anything else you want patients to know about Phase I clinical trials?
What we’re seeing in the Phase I environment is a lot of hope.
Within the past decade, there’s been an explosion of new drugs. There
are over a thousand new cancer drugs in the pipeline. We’re seeing a
lot more activity than before; drugs that are actually working in lots
of different tumors types than before. We’re also getting much more
sophisticated in how we identify patients. I’m an optimist, and I
wouldn’t be in this field if I wasn’t.
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