It's not necessary to be the flashy Dendreons (Nasdaq: DNDN) of the world trying to cure -- or at least prolong the life of -- prostate cancer patients. Sometimes it's enough to just treat the side effects of prostate cancer treatment to make money.

Witness GTx (Nasdaq: GTXI), whose stock rose more than 36% yesterday after the company released data from its phase 3 trial of toremifene to treat the side effects of androgen-deprivation therapy. The stock has lost 11% today.

After androgen-deprivation therapy with drugs such as AstraZeneca's (NYSE: AZN) Zoladex or Watson Pharmaceuticals' (NYSE: WPI) Trelstar, prostate cancer patients often get menopause-like symptoms. Definitely an unwanted side effect of an already horrible disease.

Toremifene achieved its primary goal by reducing bone fractures in patients' backs by 50%. GTx said the drug was also better than the placebo in all the other objectives except the one that patients probably find most annoying -- hot flashes. GTx is still evaluating the hot flash data, which won't be presented until the full data set is made public at a medical meeting.

The only safety concern in the trial was an elevated incidence of blood clots, which GTx could address with a warning label that says that patients at high risk of getting blood clots shouldn't take the drug.

Toremifene is in the same class of drugs as breast cancer treatment tamoxifen and Eli Lilly's (NYSE: LLY) osteoporosis drug Evista, which modulate the estrogen receptor differently depending on what cell type the receptor is attached to. GTx already sells a lower dosage of the drug, for treating breast cancer, under the brand name Fareston.

GTx plans to file a New Drug Application with the Food and Drug Administration by the summer. Because there are no approved drugs to treat the side effects of androgen-deprivation therapy, the company probably will get a six-month priority review and have an answer back from the FDA before the end of the year.

The unpopular drugmaker -- it has only 67 Motley Fool CAPS ratings -- is trying to get a little more attention. Next month, it plans to release results from another phase 3 trial testing toremifene to prevent prostate cancer in men with a premalignant lesion called prostatic intraepithelial neoplasia (PIN). If those results are as good as the ones released yesterday, more investors should take note of GTx.

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Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. Eli Lilly is a selection of the Income Investor newsletter. The Fool has a disclosure policy.