Researchers Improve Anti-Cancer Treatment

U.S. scientists have created a simple modification in an anti-cancer treatment currently in clinical trials that greatly improves the drug’s effectiveness.

The improvement by Enzon Pharmaceuticals Inc.’s David Filpula and colleagues at the National Cancer Institute is said to also reduce side effects in experiments with laboratory mice.

The research centers on an immunotoxin called SS1P that targets and destroys cells producing the surface protein mesothelin.

Ovarian, pancreatic and malignant mesothelioma cells all produce abnormally large amounts of mesothelin and, therefore, are targets for SS1P.

In the new study, researchers modified SS1P with PEGylation, which involves attaching chains of polyethylene glycol to the molecule. PEGylation is a well-established process that is used in at least six protein-based pharmaceutical products currently on the market.

PEGylated SS1Ps had fewer side effects and were more effective in mice bearing human tumors than standard SS1P, the researchers reported. A single dose of the modified SS1P resulted in complete regression of the mouse tumors — the first time that such an effect has been observed.

The research is described in the current issue of the bi-monthly journal Bioconjugate Chemistry.