New drug extends survival in advanced chemo-resistant prostate cancer

Results announced at the Genitourinary Cancers Symposium this week show impressive gains in prostate cancer, especially those with metastatic cancer and few treatment options.For men with chemotherapy-resistant advanced prostate cancer, hope may be in a new investigational chemotherapy presented at the meeting being held today through Sunday in San Francisco.Although most prostate cancers respond to hormonal therapy, or androgen deprivation therapy, some do not. These hormone-resistant prostate cancers are usually treated with Taxotere (docetaxel), but if patients progress on the drug, patients usually have few, if any, options. A newer generation taxane-based drug, cabazitaxel, could provide those patients with another treatment. The drug was shown to increase median survival by 30 percent. Of the 755 patients in the study, those who received cabazitaxel lived a median of 15.1 months compared with about 12.7 months in patients taking mitoxantrone--a highly significant difference, said Oliver Sartor, MD, who presented the study. Patients with this type of advanced prostate cancer usually have about a year survival, but Sartor noted that twice as many patients reached the two-year survival mark with cabazitaxel. "It is also, I think, particularly meaningful for patients who really don't have other alternatives today," Sartor said at a press briefing prior to the conference. Nicholas Vogelzang, MD, who moderated the press briefing Wednesday, noted that although a three month survival advantage may seem small, it is a huge advancement in terms of cancer research. "Almost all the advances in [cancers] have come in these sorts of incremental advances. Three months is a major clinical advance," he told reporters. "It is exactly the same difference that led the FDA to approve docetaxel, and docetaxel now has become more and more widely used."The phase III international study, called TROPIC, compared cabazitaxel, which is administered intravenously once every three weeks, with mitoxantrone, a commonly used chemotherapy, but one that has shown no survival benefit in this patient population. Sartor noted that researchers chose to use mitoxantrone to give patients an active therapy, as opposed to a placebo. All patients received the steroid prednisone.Further results of the study will be presented at the 2010 ASCO annual meeting in early June, including progression-free survival, tumor response rates, and prostate-specific antigen (PSA) response. However, researchers have suggested that those results are also favorable.The maker of cabazitaxel, Sanofi-Aventis, is working with the FDA on submitting the drug for approval soon and was granted fast-track status in December. If approved, it could be available as early as end of this year. Vogelzang said the argument could also be made now that the drug could be used earlier, "...now that there is something that works, the therapy might be given earlier and the survival advantage could potentially become even greater." Current trials are looking into whether the drug should be given before hormone-resistant cancers progress on Taxotere, as well as in other tumor types.You can view the study abstract at www.asco.org.