Treatment with adenoX-rCB11-A9 can suppress collagen-induced arthritis when administered after the development of established arthritis. Groups of 3 DBA/1 mice were immunized with type II collagen/complete Freund's adjuvant and at the time arthritis reached a severity score of two or greater, the mice were administered intra-articularly either adenoX-rCB11-A9 (square) or adenoX-LacZ (circle). All mice were observed for the development of arthritis. The data points reflect the mean severity score (sum of the severity scores/total number of animals in the group) at each time point. As noted the adenoX-rCB11-A9 was extremely effective at treating established arthritis, causing a reversal of the severity of the disease which persisted for a full two weeks (severity scores of 0 vs 5.1 ± 2.1, P < 0.05 on day 30 after immunization and 0 vs 7.1 ± 2.2; P ≤ 0.05 on day 44).