Figure 2. Long term immunosuppression with CP is not required for the combined effect of VRX-007 and CP against tumor growth.

HaK tumors were injected with 1×10¹⁰ PFU of VRX-007 or PBS (mock group) for 6 consecutive days. The arrows in panel a represent days on which the virus was injected. CP was given intraperitoneally biweekly starting one week before infection. The CP-1 week groups were taken off CP at the time of infection, and the CP-all groups were given CP biweekly for the duration of the study. The mock and CP-1 week groups were sacrificed on days 31 and 34, respectively, due to excessive tumor burden. The experiment was terminated at 44 days post infection because of animal welfare considerations. (a) Mean tumor volume. Error bars represent mean + SE, and the numbers of animals per group were as follows: 9 (mock); 8 (VRX-007+CP-1 week); 7 (CP-1 week); 6 (VRX-007 and CP-all); 4 (VRX-007 + CP-all). There was a significant difference in tumor growth suppression between the mock group and either of the VRX-007 + CP groups (P<0.003). There was no significant difference between VRX-007 + CP-1 week and VRX-007 + CP-all at any time throughout the study (P>0.10 throughout). (b) Virus titers in the tumor. Tumor samples for TCID₅₀ assay were taken at time of death, 44 days post infection. (*P=0.0286) (c) Serum neutralizing antibody titers. An anti-Ad neutralizing antibody assay was performed for the serum collected at 44 days post infection (P < 0.02 for all groups compared to each other).