Marshall Edwards today announced that the U.S. Food and Drug Administration (FDA) has granted the investigational anti-cancer drug, phenoxodiol, fast track status for its intended use in patients with hormone- refractory prostate cancer (HRPC).
The successful application for fast track status was based on data derived in a Phase Ib/IIa study, conducted in two Australian hospitals, in which men with late stage HRPC were treated with the oral dosage form of phenoxodiol as a monotherapy.
The preliminary outcome of this study was presented to the American Association of Cancer Research (AACR) conference on Basic, Translational and Clinical Advances in Prostate Cancer in November 2004. In the study, dosages of phenoxodiol ranging from 200mg to 400mg 8-hourly had a significant effect on disease progression, as evidenced by falls in PSA levels, and suppression of those levels for a period of at least 6 months. Most of the patients remain on phenoxodiol therapy for periods up to 18 months without evidence of disease progression.
Of particular relevance to the FDA is that prostatic adenocarcinoma that is refractory to both hormonal therapy and cytotoxic chemotherapy is associated with severe morbidity and a life expectancy of less than 1 year, and as such meets the criteria for a serious and life-threatening disease.
Under the FDA Modernization Act of 1997, designation as a Fast Track product means that the drug for the designated indication is eligible for accelerated marketing approval programs. More information on the FDA fast track program is available at http://www.fda.gov/cber/inside/fastrk.htm
"This decision of the FDA underpins our confidence in phenoxodiol being an effective therapy for late-stage prostate cancer. The next step is to take phenoxodiol into a pivotal study where we will test its ability to halt disease progression in men with prostate cancer who have failed the standard treatment of hormone therapy and docetaxel chemotherapy," said Dr. Graham Kelly, Executive Chairman of Marshall Edwards, Inc.
Mr. Christopher Naughton, CEO of Marshall Edwards, Inc., said, "This decision represents a significant endorsement of the potential of phenoxodiol, coming just 2 months after the FDA granted fast track status for phenoxodiol for late-stage ovarian cancer. The Company now has two opportunities to pursue for the continuing development of phenoxodiol for the benefit of both prostate cancer and ovarian cancer patients."
Phenoxodiol in intravenous form was granted fast track status by the FDA in November 2004 for its intended use in patients with recurrent ovarian cancer.
Phenoxodiol is an investigational product that regulates signal transduction pathways in cancer cells resulting in the break down of the intra-cellular proteins -- XIAP (X-linked Inhibitor of Apoptosis Protein) and FLIP (Fas Ligand Inhibitory Protein) -- that block the ability of the cancer cell to undergo apoptosis via the death receptor mechanism. While these proteins play a vital role in preventing unintentional cell death in healthy cells, they are over-expressed in many forms of cancer, as well as being associated with the development of resistance to anti-cancer drugs.
Phenoxodiol works selectively on tumor cells, thought to be due to its interaction with the enzyme, tumor-specific NADH oxidase, which is restricted to cancer cells. Clinical trials to date have revealed no significant drug related adverse side effects. Phenoxodiol is an investigational drug and, as such, is not approved for marketing in the United States.