Der er påvist klinisk signifikant reduktion af følsomhed over for abacavir i kliniske isolater fra patienter med ukontrolleret virusreplikation, som tidligere er behandlet med, og nu er resistente over for, andre nukleosidinhibitorer.
Clinically significant reduction of susceptibility to abacavir has been demonstrated in clinical isolates of patients with uncontrolled viral replication, who have been pre-treated with and are resistant to other nucleoside inhibitors.