New class of drugs nips cancer growth in the bud

SYDNEY - Scientists have discovered a new class of drugs that practically nips lung cancer regrowth.

In pre-clinical trials, it was found that the new drug stays active for a long time, preventing tumour regrowth. The researchers are not sure why yet, but it may be attacking the tumour’s stem cells.

Medicinal chemist Jeffrey Smaill and cancer biologist Adam Patterson of the University of Auckland announced the discovery of this new class of anti-cancer drugs in Boston in the US.

The drugs are a type of prodrug — an inactive compound that is converted into an active drug by the body’s metabolic processes.

Smaill says that the new prodrug sticks to the cancer tumour for over 72 hours while existing anti-cancer drugs stay for only a few hours.

Our experiments show that this new prodrug is much more active than the current gold-standard drug treatment for advanced or spreading lung and pancreatic cancer, says Patterson.

It’s very common for tumours to start re-growing after you stop administering this type of cancer drug. But after we stopped doses of this prodrug, the tumours still hadn’t re-grown 30 days later. The prodrug appears to act like slow-release chemotherapy.

Patterson says they are not yet sure why the prodrug stays in the tumour for so long or why it is so effective. One theory being investigated is that the released active drug is targeting the tumour’s stem cells, which initiate tumour regrowth.

The results from our pre-clinical trials also show that this prodrug need only be taken once every four to seven days. Many of the new molecular targeted anti-cancer drugs currently on the market need to be taken once or twice every day, says Patterson.

The researchers will conduct phase 1 clinical trials in humans in 2010.