TNF-PEG 20 is tumor necrosis factor alpha (TNF) conjugated with polyethylene glycol having an average molecular weight of 20 kilodaltons (PEG 20). As an early development stage biotherapeutic project, Polaris is developing a PEGylated version of the tumor necrotizing cytokine TNF for use as an anticancer agent. The PEGylation of this protein results in a potent anticancer therapeutic with unique pharmacokinetic properties.


TNF was first discovered by Dr. Lloyd Old in 1975 as an anticancer agent isolated from blood. Later work resulted in the isolation and characterization of this potent cytotoxic protein.

In Europe, non-PEGylated TNF is currently administered via isolated limb perfusion therapy to treat cancers found in the extremities, primarily soft-tissue sarcomas and metastatic melanoma. The response rate for this treatment is approximately 85%. Unfortunately, non-PEGylated TNF is acutely toxic when dosed systemically. Therefore, tumors of the internal organs cannot be targeted by current TNF-based therapy without significant co-morbidities.

Polaris is working on a PEGylated version of TNF with pharmacological properties that will make systemic dosing more feasible. Our PEGylated biologic has a significantly longer circulating half-life while still maintaining meaningful antitumor effects. Systemic toxicity can be greatly reduced using our proprietary PEGylation technology. TNF-PEG 20 is anticipated to be useful in the systemic treatment of melanomas, sarcomas and other tumors.