Prospective Black volunteers with early disease symptoms did not have enough amyloid in their brain to qualify for the trials, the 10 researchers explained.

The company told Reuters that 49% of Black volunteers did not meet the trial’s amyloid threshold requirements compared to 22% for whites and 55% for Hispanics.

That left just 43 Black participants out of 947 people enrolled in the US portion of the trial, or 4.5% of the total - a stark under-representation since the disease is most prevalent for Black Americans and they make up 13.7% of the U.S. population

The title implies racism but this isnt, primarily, about racism. You could argue that the criteria were defined like that because it was mostly white people that were studied in the past(because of racism) but ultimately, they are trying to test something under specific conditions and black/hispanic people are less likely to have those conditions.