Figure 1: Growth response of osteosarcoma xenografts to treatment with PEGylated IFN (PEG-IFN), unconjugated IFN (IFN), doxorubicin (DOX) or a combination of doxorubicin and PEGylated IFN (DOX-IFN) compared to a control group (CTR). Doses are given in equivalents to μg/kg/week. IFN was always given daily. PEG-IFN was given weekly in Figure A, C, D, E and F and every third day in Figure B, G, H. Doxorubicin was given at the maximal tolerated dose of 8 mg/kg 24 hours after start of treatment with PEG-IFN 100 (DOX-IFN). Volume is annotated as median relative tumour volume (RTV).