Novogen Limited, an Australian biotechnology company, has achieved a key milestone with its super-benzopyran (SBP) drug programme, having identified a number of SBP compounds with potent anti-cancer activity against human prostate cancer cells in vitro. As a result, Novogen has extended its preclinical SBP programme to include prostate cancer as well as ovarian and brain cancers.

Prostate cancer cells are highly resistant to chemotherapy and the few drugs approved for late-stage, hormone-resistant prostate cancer offer only modest improvements in survival. There is thus an urgent need to develop drugs specifically against prostate cancer that will prolong life to a meaningful degree for these advanced patients.

In a study conducted by Australian oncologist, Paul de Souza, Foundation Professor in Medical Oncology at the University of Western Sydney's (UWS) and who is also affiliated with the Ingham Institute, a number of SBP compounds were tested in vitro against five different prostate cancer cell lines that most closely mimic common clinical situations.

"There is a significant need for more effective treatments for prostate cancer. It's exciting at long last to be working with new compounds with such impressive activity against a panel of clinically-relevant prostate cancer cell lines," Prof, de Souza said. "With anti-cancer activity down around 50 nanomolar levels, this group of chemicals appears to be at least as active as standard cytotoxic drugs such as cisplatin. We now can work to bring the lead compound into the clinic."

The studies in the laboratory of Professor de Souza are funded by Novogen and are part of an international research program initiated and coordinated by Novogen and involving some of the world's most prestigious universities and hospitals. An ongoing structural-activity-relationship drug discovery program has produced a sub-family of SBP compounds with high potency against prostate cancer cells. A lead candidate compound has been identified and now will enter its lead optimization phase.

Professor de Souza will be the Lead Investigator in this program, with the aim of testing the investigational drug as a monotherapy in Australia in 2015 in men with advanced prostate cancer who have failed standard of care. At the same time, Novogen will file an investigational new drug (IND) application with the US Food and Drug Administration (FDA) seeking permission to conduct a US clinical trial, also in 2015.

Novogen's proprietary SBP drug technology platform targets an oncogene that appears to be common to all forms of cancer. The oncogene produces a mutant form of an enzyme that regulates fundamental biochemical processes within all cells. When inhibited, the cell quickly dies. This mechanism of action offers the potential for SBP drugs to avoid the common problems associated with targeted therapies of the cancer cell being able to develop alternative signaling pathways or multi-drug resistance mechanisms. Other studies funded by Novogen at prestigious US universities have already have identified two SBP structures with particular activity against ovarian cancer and glioblastoma cells respectively.

Dr David Brown, Novogen Group Chief Scientific Officer, said today, "The horizon for new and effective chemotherapeutics for prostate cancer is bleak. This discovery heralds in an entirely new and exciting area of clinical development. Other SBP compounds have already shown a potent ability to kill the full hierarchy of cancer cells within ovarian cancer and the main form of brain cancer, glioblastoma, and we have every confidence that what we are seeing in this study is the potential to do the same thing with prostate cancer."

"The prostate cancer cells used in this study respond poorly both in the laboratory and in the clinic to standard chemotherapy drugs, so our ability to kill them at such low drug concentrations suggests that we have broken through an important barrier."

Dr Graham Kelly, Novogen CEO, said, "This discovery extends Novogen's clinical focus into an entirely new area of cancer where patients desperately need new, better treatment options. We're excited to be moving all three of these programs forward towards human clinical trials."

SBPs are a proprietary family of compounds that inhibit the internal trans-membrane proton pump mechanisms within cancer cells. The target is a nicotinamide adenosine dinucleotide hydrogen (NADH) oxidase enzyme complex that regulates the movement of protons (hydrogen ions) across cellular membranes in support of a range of cellular functions including ATP production. The NADH oxidase isoforms targeted are tumour-associated, splice variants of normal NADH oxidases.