Effect of MORAb-009 on tumor growth. (A) A431-K5 cells were inoculated in the flank of nude mice to establish tumors of approximately 50 mm³ in size. On day 7, mice were treated with the control IgG1 Rituximab (CT IgG, 50 mg/kg), MORAb-009 (50 mg/kg), or mesothelin-specific immunotoxin SS1(scFv) (immunotoxin, 0.2 mg/kg). Average tumor size for each treatment group was calculated on day 7-17. (B and C) A431-K5 cells were inoculated as described in A. On day 7, mice were treated with vehicle, control IgG (CT IgG, 50 mg/kg), MORAb-009 (50 mg/kg), gemcitabine (Gem, 80 mg/kg), or combinations of these drugs (see Material and methods for regimens). Average tumor size for each treatment group was calculated on day 7-17 (panel B) and day 19-28 (panel C). Best anti-tumor responses were observed with gemcitabine plus MORAb-009. (D) Same model as in panels A-C, whereby mice were treated with vehicle, MORAb-009 (50 mg/kg), Taxol® (50 mg/kg), or combinations of these drugs. MORAb-009 enhanced the anti-tumor effect of Taxol®.