Figure 7. Percentage changes in tumour perfusion with combretastatin (CA4P) at (A) 30 min and (B) 24 h after infusion. A threshold response is clearly seen. Kindly reproduced with permission from: Anderson H, Yap J, Miller M, Robbins A, Jones T, Price P. Assessment of pharmacodynamic vascular response in a Phase I trial of combretastatin A4 phosphate. J Clin Oncol 2003;21:2823–30.