The Importance of Diversity in Clinical Trials

The disproportionate representation of certain segments of the population in clinical trials is no secret, and research has shown that psoriasis studies are the least racially diverse of all dermatology studies in the US.¹ Shahram Jacobs, MD, medical director at Unison Internal & Integrative Medicine/Unison Clinical Trials, spoke with Practical Dermatology about making a concerted effort to match real-world demographics in a phase 3 trial for TAK-279, an oral allosteric tyrosine kinase 2 (TYK2) inhibitor from Takeda for treating plaque psoriasis and psoriatic arthritis.

How much of an issue is diversity in clinical trials in general? 

It's an important issue, both in terms of trying to come up with treatments that help people across the board and in terms of being able to include a whole section of the population that might be more inclined to look at clinical trials in a suspicious way. Being able to have people of different backgrounds—different races and economic backgrounds—participate in clinical research really helps to increase the population of people who are available so clinical trials can be done more effectively and enrollment completed more quickly. This allows for quicker results and, most importantly, results that are valid across a wide spectrum of patients. And I can use some of the psoriasis trials as an example: There are certain treatments currently available for psoriasis, such as TNF inhibitors, for which the clinical trials have shown lower efficacy in certain populations—for example, in Asians—because of some genetic variations. And this is not something that was known, let's say 10 or 15 years ago.

How much more is there to learn about other skin types and how psoriasis might need to be treated differently?

A very easy example is people with different skin tones. Not only is the way that you evaluate the severity of psoriasis affected by the person's skin tone, but also the results they can expect after treatment are dependent on the skin tone. It's very important for the patients to know what to expect. When we're grading the severity of psoriasis, we look at three main factors. One is how much erythema is present; the second is the thickness of the lesions; and the third is the degree of the skin scaling on top of those lesions. For people with darker skin, you always need to recognize that, even though you might see only a slight darkening of the skin tone, it's at least one or two notches more severe than you might judge if you're looking at the same comparison with someone who has lighter skin. Another factor for people who have darker skin tones is that you need to make them aware that they might see the scaling and the plaques go away completely, but they may not see the skin tone going back to the same as the surrounding areas that were not affected with the psoriasis. They usually have some residual hyperpigmentation, even though there is no evidence of any psoriasis on the skin.

How did you approach trying to achieve more diversity in your trial? Was it as simple as just making a point to seek out diversity?

No, it is not that simple. At our site, we have tried to go on platforms and go to areas where there is more density of the population that we're seeking. For example, we've done some of our advertisements in Spanish. We've done several outreach programs around places like community centers and local fairs to try to reach that diverse population. The most important part is to spend the time educating people. It's one thing for a patient to have the disease and even be slightly interested in at least learning more about a clinical trial or a new potential treatment, but it's a whole different thing for them to actually participate. Something we try to do for all of our patients, but that has proven to be particularly effective in drawing a more diverse patient population, is spending time just sitting there, really answering their questions, really explaining to them what the treatment is, what the potential drawbacks may be, and what the potential benefits may be. That rapport, that relationship that you can develop when you spend time talking to the patients, is a big factor.

What are some other challenges that need to be overcome in achieving this diversity?

We need to try to design the protocols to make it easier to have a more diverse population participate in the trials. Sometimes that's difficult because science is science and if you need to get to certain markers after they're exposed to a medication before and after, within certain hours, those things are not very flexible. But there's some room to make adjustments like a longer window for visits or less frequent visits, so that people who have, perhaps, a more rigorous work schedule, or people who may not have the luxury of having their childcare extended can still participate in clinical trials. If these and other factors could be adjusted even slightly, it would be very helpful.

Do you think these initial efforts will make a wider impact and really catch on?

That's a very good question. I am not sure that it's getting the attention it should be getting, but I think it's just a matter of time. I think once more physicians, especially investigators doing clinical trials, recognize the benefits that can be gained for patients by increasing the diversity in various types of clinical trials, then they're going to be a lot more excited to participate, promote, and strive to achieve it.

Do you think we might see a push from the community of dermatologists and maybe even patients for more diverse trials?

I certainly hope so. I certainly do hope so. 

1. Chen V, Akhtar S, Zheng C, Kumaresan V, Nouri K. Assessment of Changes in Diversity in Dermatology Clinical Trials Between 2010-2015 and 2015-2020: A Systematic Review. JAMA Dermatol. 2022;158(3):288-292. doi: 10.1001/jamadermatol.2021.5596.