PEG–drug-conjugates in clinical trials.

Name	Polymer	Drug	Function	Results	Clinical trial	Reference
Prothecan	PEG	Camptothecin (with glycine linker)	Gastric and gastroesophageal tumors	Lower drug loading of 1.7 wt% as compared to other polymers	Phase II	68–70
				Better efficacy in animal models of human tumors than free camptothecin
EZN-2208	PEG	SN38 (camptothecin analog)	Metastatic breast tumor	Prolonged blood circulation half-life	Phase II	71 and 72
				Increased tumor to plasma drug concentration ratio
NKTR-102	PEG	Irinotecan	second line colorectal tumor, metastatic breast tumor, platinum-resistant ovarian tumor and metastatic cervical tumor	Prolonged half-life of 15 days as compared to free irinotecan (4 h)	Phase II	66
				1.2–6.5 fold higher cumulative exposure