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【drug-news】另一个有希望的肿瘤疫苗正在测试
Another Cancer Vaccine Promise In Test
Shares of Cell Genesys of South San Francisco leapt more than 32 percent Tuesday after the company said its experimental prostate cancer drug performed better than expected in a clinical trial, adding momentum to the fast-developing cancer vaccine field.
Last week, Provenge, an experimental prostate cancer vaccine developed by Seattle's Dendreon Corp., got a favorable review from a Food and Drug Administration advisory panel, raising the odds that it will be the first therapeutic cancer vaccine approved in the United States.
Tuesday, the positive news concerned Cell Genesys' Gvax. Analysts said data from a small study suggest that the vaccine may extend the lives of men with prostate cancer more effectively than an approved chemotherapy regimen and may deliver comparable or greater survival results than Provenge.
The positive Provenge review Thursday re-energized the cancer vaccine field, which has seen many disappointing final studies on once-promising treatments. Investors are piling in.
Dendreon shares closed at $14.65 Tuesday, nearly three times their value before the panel review. Cell Genesys shares gained $1.39 to close at $5.70 Tuesday. The shares have gained 77 percent since Dendreon's favorable reception by the FDA advisory panel . Other cancer vaccine developers have seen similar increases.
Cancer vaccines, also called cancer immunotherapies, are different from vaccines that prevent disease. They are designed to train the immune system to attack cancer that has already developed.
Cell Genesys' Gvax report was based on the type of a small clinical trial typically carried out during the middle stage of drug development, known as Phase II. The encouraging findings confirmed the survival trend it reported in 2002 from a previous Phase II study and could give an early snapshot of the anticipated outcome in a much larger trial that the company hopes will lead to FDA approval after it is completed in 2009.
Those larger studies, known as Phase III trials, occur in the later stages of drug development and are designed to provide the FDA with enough information to fully evaluate a product's safety and effectiveness.
"We are encouraged," chief executive Stephen Sherwin said. But Sherwin emphasized that preliminary Phase II trials cannot give the definitive picture of the drug's activity that will emerge from the Phase III trial. He also cautioned against comparisons between the early trials of Gvax and the late-stage trial of Provenge that Dendreon submitted to the FDA.
Cell Genesys is hoping to prove that Gvax works better while producing fewer side effects in advanced prostate cancer than the FDA-approved chemotherapy drug Taxotere. The median survival time of patients who take Taxotere after hormonal therapy fails is 18.9 months, according to published research.
This can vary, however, depending on how advanced the disease is in subjects admitted to particular clinical trials.
In 2002, Cell Genesys said 34 patients on two different dose levels of Gvax had a combined median survival of 26.2 months.
In the trial data released Tuesday, 22 patients given the highest dose of Gvax had a median survival of 35 months. Based on their symptoms before treatment, Cell Genesys had estimated median survival at 22 months. The high dose in that trial is the same as that being used in Phase III trials of Gvax.
Dendreon is pinning its hope of FDA approval for Provenge on an apparent 41/2-month median survival improvement in a similar population of prostate cancer patients. John McCamant, editor of the Medical Technology Stock Letter in Berkeley, said the preliminary Gvax data compare favorably to Provenge results. In addition, Gvax might be easier to commercialize if the two products ever go head to head, he said.
Gvax is a standardized "off-the-shelf" treatment, while Provenge is a customized preparation made from a cell sample drawn from each individual patient. The FDA is expected to decide on Provenge's approval by May 15. 本人已认领该文编译，48小时后若未提交译文，请其他战友自由认领。 原文3388 译文1226
Another Cancer Vaccine Promise In Test
另一个有希望的肿瘤疫苗正在测试
Shares of Cell Genesys of South San Francisco leapt more than 32 percent Tuesday after the company said its experimental prostate cancer drug performed better than expected in a clinical trial, adding momentum to the fast-developing cancer vaccine field.
星期二，当南圣弗朗西斯科的Cell Genesys公司宣布它的实验性的前列腺癌药物在临床试验中的表现比预期的要好后，它的股票上涨了超过32个百分点。这个消息给快速发展的癌症疫苗领域增加了动力。
Last week, Provenge, an experimental prostate cancer vaccine developed by Seattle's Dendreon Corp., got a favorable review from a Food and Drug Administration advisory panel, raising the odds that it will be the first therapeutic cancer vaccine approved in the United States.
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作者:admin@医学,生命科学 2011-08-06 05:11
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