Cytodyn would have done genetic testing of patients to exclude those with the double allele CCR5 delta 32 variant. Since they don't express surface CCR5 leronlimab would not be of benefit to them. That same genetic test would show if they were single allele CCR5 delta 32. If Cytodyn did not exclude patients with single allele then they would just need to go back and look at the DNA tests to see if there is any correlation between single allele and non-responders.