Enzon Commences Enrollment of Two Phase I Studies of PEG-SN38

Enzon Pharmaceuticals announced that several patients have been enrolled in two Phase I studies of PEG-SN38 (EZN-2208), the company’s pegylated form of SN38, the active metabolite of the cancer drug Camptosar.

According to Enzon, these studies are designed to evaluate the safety, tolerability and pharmacokinetics of PEG-SN38 the active metabolite of the cancer drug Camptosar (irinotecan HCl injection) in different dosing schedules for patients with advanced solid tumors or lymphoma.

Although unmodified SN38 is 1,000 times more potent than Camptosar, it has not been converted into a viable drug candidate because it is insoluble, the company said. Using pegylation technology, the company developed PEG-SN38 (EZN-2208), which results in a compound with increased solubility, higher exposure and longer half-life than unmodified SN38.