Marshall Edwards, the US-based subsidiary of Australian cancer drug developer Novogen (ASX:NRT, NASDAQ:NVGN), has begun a phase Ib/IIa trial of Novogen's investigational chemotherapy re-sensitising drug phenoxodiol.

Researchers at Yale University will trial a combination of phenoxodiol and the second-generation taxane-group chemotherapy drug docetaxel in 60 women with recurrent ovarian cancer, who have developed high-level resistance to docetaxel and other chemotherapy agents, including paclitaxel -- another taxane.

The volunteer patients have recurrent cancers of the ovarian epithelium, fallopian tubes or abdominal cavity after originally being treated with a platinum agent and paclitaxel. After such treatment, high-level drug resistance becomes an obstacle in treating recurrent tumours.

All the women will receive a weekly docetaxel injection; 50 per cent will also be given daily, oral phenoxodiol while the others will receive a placebo tablet.

Novogen said the tumour response would be assessed by monitoring tumour burden in patients with measurable disease, and tumour-marker levels in those with no overt cancer.

The company will also compare disease-free survival time in the experimental and control groups; the women will remain on the treatment for 12 months, barring toxicity or disease progression.

Phenoxodiol has already been shown in pre-clinical studies to reverse docetaxel resistance in cancerous ovarian cells.

Lead Investor Dr Thomas Rutherford said in a statement that advanced-stage ovarian cancer remains one of the most devastating of all cancers. The mortality rate in women with ovarian cancer is 50 per cent within 5 years of diagnosis.

Rutherford said one of the imperatives facing doctors treating women for ovarian cancer was to find a way to restore their sensitivity to taxanes, the front line drugs for ovarian and breast cancer.

He said the preclinical and phase I trial results of phenoxodiol's performance as a re-sensitising agent (it has cancer-fighting properties in its own right) give reason for optimism that that will prolong the survival of late-stage cancer patients in the trial.