Newswise — The 20 year survival rate for men diagnosed with prostate cancer is better now than it was in the 1980s, partially because of early detection with PSA testing and the development of more effective treatment options, like androgen deprivation therapy, or ADT. Prostate cancer is still, however, the second leading cause of cancer deaths in men, with more than 28,000 American men expected to die from the disease in 2008. Despite this high mortality rate, researchers are debating whether prostate cancer patients are being over treated with ADT, as ADT can cause multiple serious and life threatening side effects.
GTx, Inc., a biopharmaceutical company based in Memphis, is developing toremifene citrate, a selective estrogen receptor modulator, or SERM, currently under investigation for the treatment of the side effects of ADT (80 mg dose), as well as the prevention of prostate cancer in high risk men with the precancerous lesion known as high grade prostatic intraepithelial neoplasia, or high grade PIN (20 mg dose). In late February, GTx announced positive results of the Phase III clinical trial of toremifene citrate 80 mg for the treatment of the side effects of ADT. GTx expects to file a New Drug Application (NDA) with the United States Food and Drug Administration (FDA) by summer 2008. The Company expects to announce the results of an efficacy interim analysis of the Phase III clinical trial of toremifene citrate 20 mg for the prevention of prostate cancer in men with high grade PIN soon.
"We are excited by the recently announced positive results of the toremifene citrate 80 mg Phase III ADT clinical trial and are working expeditiously to file a new drug application," said Mitchell S. Steiner, MD, CEO of GTx. "If approved, toremifene citrate 80 mg could help men with advanced stage prostate cancer who are on ADT manage estrogen related side effects. In addition, we are eagerly anticipating Phase III data from our toremifene citrate 20 mg Phase III high grade PIN clinical trial. With successful Phase III results and FDA approval, toremifene citrate 20 mg could be the first product indicated for the prevention of prostate cancer in a large group of high risk men."
About Toremifene CitrateToremifene is a selective estrogen receptor modulator, a small molecule which binds to estrogen receptors but displays different clinical activities, acting either as an estrogen or as an antiestrogen, depending on tissue type. GTx's clinical trials are designed to evaluate whether toremifene displays positive estrogenic activity by building bone, maintaining cholesterol levels, and regulating certain pituitary and central nervous system functions, and whether toremifene displays antiestrogenic effects in the breast and prostate, where it blocks the harmful estrogenic activity which can stimulate tissue growth.
Toremifene Citrate 80 mg for the Treatment of Side Effects of ADTAndrogen deprivation therapy (ADT) is the primary treatment for advanced prostate cancer. It works by lowering testosterone and estrogen, ultimately forcing the cancer into remission. However, these low estrogen levels can also lead to serious side effects such as bone loss and increased risk of fractures, lipid changes and increased risk of cardiovascular disease, hot flashes, and gynecomastia (breast pain). Studies have shown that median survival falls by more than three years in patients who develop a skeletal fracture.
Recently, GTx released positive Phase III clinical trial results showing that toremifene citrate 80 mg reduced new morphometric vertebral fractures in prostate cancer patients on ADT, the primary endpoint of the Phase III ADT clinical trial, and also increased bone mineral density, improved lipid profiles, ameliorated gynecomastia, and reduced hot flashes in men experiencing a high number of hot flashes per day.
Toremifene citrate 80 mg had a favorable safety profile and was well tolerated. Among the most common adverse events that occurred were joint pain (treated 7.3%, placebo 11.8%), dizziness (treated 6.3%, placebo 5.0%), back pain (treated 5.9%, placebo 5.2%), and extremity pain (treated 5.0%, placebo 4.4%).
Based on these findings, GTx plans to file an NDA with the U.S. Food and Drug Administration (FDA) by the summer of 2008. Also, data will be presented at the upcoming annual meeting of the American Association for Cancer Research.
Toremifene Citrate 20 mg for the Prevention of Prostate CancerHigh grade prostatic intraepithelial neoplasia (PIN) is the precancerous lesion of the prostate, which is detected in approximately 115,000 men each year by needle biopsy. More than 40 percent of these men progress to prostate cancer within three years. Currently, there is no approved treatment to prevent prostate cancer in men with this precancerous lesion.
Toremifene citrate 20 mg is being studied as a daily tablet to prevent prostate cancer in men with high grade PIN. GTx plans to conduct an efficacy interim analysis of the Phase III clinical trial evaluating toremifene 20 mg for high risk men with high grade PIN in early 2008.
Additional Hormone Related ResearchGTx recently entered into a global strategic collaboration with Merck & Co., Inc. for the discovery, development and commercialization of selective androgen receptor modulators, (SARMs). This new class of drugs has the potential to treat a variety of indications associated with muscle wasting and bone loss, including sarcopenia, or age related muscle loss, and cancer cachexia, the progressive and preferential loss of muscle in cancer patients.
A Phase II clinical trial demonstrated the ability of GTx's lead SARM, Ostarineâ„¢ (MK-2866), to build muscle and improve physical performance in elderly men and postmenopausal women. GTx is currently evaluating Ostarine for the treatment of cancer cachexia in a Phase IIb clinical trial. Results are anticipated by the end of the summer 2008.
About GTxGTx, Inc., headquartered in Memphis, Tenn., is a biopharmaceutical company entering its second decade. The Company is a recognized leader in the discovery and development of novel small molecules that selectively target hormone pathways to treat cancer, osteoporosis and bone loss, muscle wasting and other serious medical conditions.
Forward-Looking Information is Subject to Risk and UncertaintyThis press release contains forward-looking statements based upon GTx's current expectations. Forward-looking statements involve risks and uncertainties. GTx's actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation, the risks that (i) GTx and its collaboration partners will not be able to commercialize their product candidates if clinical trials do not demonstrate safety and efficacy in humans; (ii) GTx may not able to obtain required regulatory approvals to commercialize product candidates; (iii) clinical trials being conducted by GTx and its collaboration partners may not be completed on schedule, or at all, or may otherwise be suspended or terminated; and (iv) GTx could utilize its available cash resources sooner than it currently expects and may be unable to raise capital when needed, which would force GTx to delay, reduce or eliminate its product development programs or commercialization efforts. You should not place undue reliance on these forward-looking statements, which apply only as of the date of this press release. GTx's registration statement on Form 10-K filed March 11, 2008 contains under the heading, "Risk Factors," a more comprehensive description of these and other risks to which GTx is subject. GTx expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in its expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based.
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