US, Japanese to trial NZ lung cancer drug

Photo / Peter Meecham

Japanese and American companies plan to commission clinical trials of a promising lung cancer drug developed in New Zealand.

The drug, called PR610, is part of a new class developed by scientists at the Auckland Cancer Society Research Centre and the Maurice Wilkins research centre. They preserve healthy tissue by becoming active only in the "hypoxic" parts of tumours - the zones without oxygen.

PR610 follows PR509 in being picked up for clinical development under a deal between Japanese pharmaceutical company Yakult Honsha and American biotechnology company Proacta.

Both drugs have been targeted for development in non-small-cell lung cancer that is resistant to established treatments.

They are also likely to be evaluated in treating cancers of the stomach, breast and pancreas.

John Loof, chief executive of the Cancer Society's Auckland division, said the experimental drugs were a breakthrough by the Auckland University-linked researchers.

The university has licensed the development of the "hypoxia-activated" drugs to Proacta. The university says the pre-clinical data on PR610 is "compelling".

Two-thirds of tumours contain hypoxic zones and the cancer cells in these areas are more resistant to treatment. They are an important cause of treatment failure and relapse.

The researchers' new class of "pro-drugs" targets human epidermal growth factor receptors which are involved in normal cell growth and are overactive or mutated in many cancers. The process of converting the pro-drugs to their active, toxic form can't occur in oxygen, so healthy tissue is protected.

These drugs stay in tumours for longer than existing drugs that target human epidermal growth factor receptors.

One of the researchers, Dr Jeff Smaill has said previously: "By preventing toxicity in healthy tissues and achieving long residency and slow release within cancerous tissue, we can deliver much more drug to a tumour than is possible with standard chemotherapy.

"This is associated with far greater efficacy against tumours."