Black patients benefit less from ranibizumab


Black patients have less improvement in visual acuity than white patients when treated with ranibizumab for diabetic macular edema, according to available data from clinical trials.

The difference between races disappears when the stats are adjusted for factors like HbA1c levels. But the findings raise questions that highlight the lack of data on ethnicity in clinical trials of retinal treatments, said Ali Khan, MD, assistant professor of ophthalmology at Thomas Jefferson University at Philadelphia.

“The ultimate message from the project is that we need to do a better job of recruiting patients from diverse backgrounds,” he said. Medscape Medical News.

Khan presented his findings at the 2021 American Society of Retina Specialists (ASRS) annual meeting.

Few researchers have reported differences between racial or ethnic groups in response to treatments for retinal conditions. “And obviously, with the George Floyd protests, I think people got a little more interested in making sure that we set things right when it comes to diversity and inclusion,” Khan said.

For example, Khan and colleagues reviewed data from the Diabetic Retinopathy Clinical Research Network (DRCR) I, S, and T protocols and the RISE and RIDE trials of ranibizumab funded by Genentech.

They counted a total of 928 white patients and 181 black patients in the five trials. They found that white patients started with a best-corrected mean observed visual acuity (BCVA) of 62.0 ETDRS letters, which rose to 72.2 after 24 months, for improvement from baseline of 10.0 letters. Black patients started with an average of 66.7 letters, which rose to 72.8, an improvement of 7.8 letters. The difference in improvement letters was statistically significant (P = .04).

At the same time, 27.6% of black patients and 35.0% of white patients had gains of at least 15 letters, which is just short of statistical significance (P = .05).

The differences between the two races came from the RISE and RIDE data; the differences in the other trials were not statistically different.

And those differences disappeared when the researchers compared black patients to white patients who had similar age, gender, HbA1c, central subfield thickness, and BCVA initially, and a similar number of injections and of ranibizumab visits after 24 months.

The same was true when patients were matched on all of these characteristics except HbA1c, and also when only baseline characteristics were considered.

The researchers would have liked to include more factors, such as kidney function and socioeconomic aspects in their analysis, but limited themselves to what had been collected in those trials, Khan said.

Likewise, they were unable to analyze differences involving Asians, Latinxes, and other ethnic and racial groups because these trials did not include enough patients from these groups.

It might be useful to subdivide some of these racial and ethnic groups, for example, by distinguishing people of ancestry from different parts of Asia or Latin America, he said.

The under-representation of people of color is common to other medical specialties, Khan said. “It just means that we have to do a better job of getting these patients into clinical trials, and how to get there is the more difficult question,” he said.

Hiring more principal investigators of color might help, he said, adding that the researchers should work to overcome language barriers.

Research in other medical specialties has identified socio-economic factors and mistrust of health professionals as factors limiting recruitment from under-represented groups, said Abdul-Hadi Kaakour, MD, MS, researcher at the Cleveland Clinic, in an email.

In a related study, Kaakour presented to ASRS, he and his colleagues compared the representation of ethnic and racial groups in 15 randomized controlled trials in diabetic macular edema. They found that:

  • the cohort of white patients was under-represented in two and over-represented in 10

  • the cohort of black patients was under-represented in six and over-represented in three

  • the Hispanic patient cohort was under-represented in nine and over-represented in three

  • the Asian patient cohort was under-represented in eight and over-represented in three

  • the Native American / Alaska Native and Hawaiian / Pacific Islander patient cohort was under-represented in four cases.

“Each person’s barriers will also be unique, so at the very least spending more time with patients who identify as under-represented minorities will allow the clinician to understand their particular barriers and find constructive ways to overcome them. “Kaakour said. Medscape Medical News.

Neither Kaakour nor Khan reported any relevant financial interests. Funding was provided by Genentech for the study presented by Khan.

American Society of Retina Specialists (ASRS) 2021 Annual Meeting. Presented October 9, 2021.

Laird Harrison writes on science, health and culture. His work has been featured in national magazines, newspapers, public radio, and websites. He is working on a novel on alternative realities in physics. Harrison teaches writing at Writers Grotto. Visit him at follow him on Twitter: @LairdH

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