Anti-tumour response of RIT alone or in combination with chemotherapy. LL2 tumour bearing mice were left untreated, or treated with chemotherapy (chemo) and/or RIT (177Lu-DAB4 or 177Lu-Sal5). (A) Left panel, percentage change in tumour volume after treatment. Right panel, Kaplan-Meier survival analysis, ** p < 0.01 compared to untreated mice, n = 5. (B) Comparison of the anti-tumour effect of escalating doses of RIT when delivered after chemotherapy. Left panel, percentage change in tumour volume after treatment. Red symbols = toxic dose. Right panel, Kaplan-Meier survival analysis, ** p < 0.01 compared to mice given chemotherapy alone, n = 5. (C) Mean tumour doubling times derived from tumour growth curves are displayed as a function of RIT dose. Standard errors for data points range from 0.03 to 0.15, and are too small to be evident as error bars. Data shows that the combination of chemotherapy and RIT is supra-additive because the slopes of the two lines are significantly different (p = 0.02; analysis of covariance).