Ms. Marie Vastola is a Clinical Research Assistant in Radiation Oncology at Dana-Farber/Brigham and Women’s Cancer Center. She works on Dana-Farber-led and international clinical trials that accrue men with multiple stages of prostate cancer. She is an author on six research articles focusing on prostate cancer and has presented her research at a national conference.
Dr. Paul Nguyen is an internationally recognized expert in prostate cancer clinical care and research. He has published over 250 original research articles and has various national leadership roles and is the Dana-Farber Cancer Center Genitourinary Clinical Center Director for Radiation Oncology, Vice-Chair for Clinical Research in the Department of Radiation Oncology, and Associate Professor at Harvard Medical School.
Prostatepedia spoke with them about how eligibility requirements for prostate cancer clinical trials may unfairly exclude African American men.
How have black men been underrepresented historically in prostate clinical trials? What are some of the prevailing theories or ideas about why that might be?
Dr. Nguyen: It’s multifactorial, and that was something that our research aimed to get at. Because of the historical experiences like the Tuskegee experiment, some African- Americans may have been more leery of engaging in clinical trials. Because trials require certain costs and extra time away from work, this can be more difficult on certain populations. Or it could be from the doctor side. Some doctors may not be as willing to engage African-American patients to enroll them on trials. There are multiple factors, so it’s hard to know exactly what is the main driver.
Ms. Vastola: We have patients come from long distances to Dana-Farber, and they do that because they know that Dana-Farber is a good place for them to get treated. Many patients, especially ones who travel long distances, either have connections in the medical field and that’s how they found out about this, or they’re highly educated and they have the resources to look into research and potential treatments themselves. These are tools that only people who are a little more privileged have.
Why did you zero in on eligibility criteria? What were you looking at?
Ms. Vastola: Actually, a patient is what started this research project. I had been screening an African-American patient for one of our open trials, and filling out the paperwork to determine if he was eligible. Most of this paperwork is related to the cancer, to make sure that patients have the type of cancer that we’re studying. But other sections of the checklist establish that the patient is otherwise healthy. We wouldn’t want to give an experimental treatment to a patient who wasn’t healthy for their sake and for the research’s integrity. He didn’t meet the criteria for one of those health checks.
One of the ways we determine that a patient is otherwise healthy is to look at their immune function, and his white blood cell count was too low. I hadn’t seen that before, and we ran his blood test again. His medical oncologist said the patient had benign ethnic neutropenia, which I had never heard of it until then. Because of that he couldn’t go on the trial that we had. It wasn’t a trial that we were running out of this hospital, but we talked to the sponsors. And as with many big trials, they don’t allow exceptions, no matter what.
He didn’t get the opportunity to be on a trial that was designed for men just like him, and that was really frustrating. Everyone involved with his treatment was frustrated with that, and so we looked into if that could be happening to other men. We also looked at creatinine. It’s well known in the medical field that black patients have a higher serum creatinine, and so you have to use a special formula that accounts for race when you’re looking at their kidney function. We looked at benign ethnic neutropenia because that’s what started it, and it was something that people seemed unaware of.
Dr. Nguyen: In a research group, the ideas usually come from the lab principal investigator (PI), and then the junior people carry it out. In this case, Marie actually came up with this idea herself because of a patient experience that she had, seeing an African-American patient not be able to get on one of our trials. It’s what led to this Journal of the American Medical Association Oncology paper, which is impressive.
That is. What did you look at?
Ms. Vastola: We wanted to know how often this happens. Was this a fluke, or does this happen to other African-American men? The best way to find out was to look at the eligibility criteria of other trials. Every trial records when people don’t meet the criteria. They don’t often record why though, so we couldn’t just look at the internal records of our trials. The website clinicaltrials.gov lists all trials available to patients in the United States and also a lot of international trials, and it usually lists the eligibility criteria. Not all the trials go into detailed criteria, but many do. We went through 401 trials that had endpoints that we thought meant that they had the potential to reach large audiences and change practice. We looked at all of them and pulled the eligibility criteria to see how many of them had this white blood cell criterion.
We expected some would have it. We did not expect that almost 50% of trials would have either of these two criteria. We were also surprised that the serum creatinine criterion was so common that a quarter of the trials have it.
People are aware of this, and they know to calculate kidney function accounting for race. A lot of trials would use serum creatinine, which is just the blood test, but then they would also say that if a patient meets formula criteria (based on race), then they’re okay, which is what we want to see. Not all trials do that, and that’s the issue. Every single lab result you look at that measures creatinine says at the bottom that if the patient is African-American, apply this formula. But over 25% of these trials weren’t including that formula.
What else did you find?
Ms. Vastola: Those were the two criteria that we looked at. We also broke it down by year, size of the trial, the phase, and toxicity of the therapy. We were glad to see that, over time, people are using the serum creatinine eligibility criteria less and less, which may mean that more people are aware of it. That’s not the case for the white blood cell criterion though.
Dr. Nguyen: We looked only at trials that have survival as an endpoint, so these are trials looking to make people live longer. We think it’s especially important that all patients have equal access to these kinds of trials. There are a few consequences of not having African-Americans on these trials. Patients who go on trials can sometimes get access to new drugs, so it’s a problem if African-American patients aren’t getting on trials. We also don’t get to learn enough about whether certain drugs perform particularly well in African-Americans, and so we don’t get to learn about the specific benefits or lack of benefit of certain agents for African-American patients. We wind up extrapolating from the larger patient pool, which probably works most of the time, but perhaps there’s something special that we can learn from having African-American patients on trials so that we could find better cures that can be tailored for African-American patients.
Ms. Vastola: Exactly. Not having access to these clinical trials hurts the individual because they don’t have access to treatment that could potentially help them. But the lack of access also hurts the whole population.
It also skews your results, so that what you’re learning about isn’t really prostate cancer in all men, just prostate cancer in a subset of men.
Ms. Vastola: Exactly.
What do you hope this will mean for clinical trial design and eligibility recruitments?
Ms. Vastola: We presented this research letter at the Prostate Cancer Symposium of the American Society for Clinical Oncology in poster form. We got a lot of feedback from academic investigators, people who devote their lives to this. Their papers define the field. They said they’d never thought of this, and that some didn’t know benign ethnic neutropenia existed. This section of the eligibility criteria—the part that defines whether a patient is healthy—is just carried over from trial to trial because it’s so standard. It’s not something people think about when they design trials because it’s so standard.
It’s textbook. We hope that, as more people understand this, they will consider it when they design their trials.
Dr. Nguyen: We were guilty of it in our own trials, and that’s how this all came about. We just used standard entry criteria copied over from previous studies. We were surprised to learn that this could disproportionally disadvantage African-American patients from being able to enroll in our trials. Given all the barriers that African-American patients face in getting on clinical trials in the first place, the last thing that we need is yet another barrier.