The FDA today approved Provenge, Dendreon Corp.'s individualized "vaccine" for the treatment of advanced prostate cancer. The action comes more than three years after an FDA advisory panel recommended approval, declaring the immune therapy safe and effective. But FDA concerns over efficacy led the FDA to delay a decision until more data became available.

Provenge isn't your everyday vaccine. It's an immune therapy created by harvesting immune cells from a patient, genetically engineering them to fight prostate cancer, and then infusing them back into the patient.

It's approved only for treatment of asymptomatic or minimally symptomatic patients with prostate cancer that has spread outside the prostate and no longer responds to hormone therapy.

In clinical trials, Provenge extended survival by a median 4.1 months -- about half of patients were below that amount and half were above. But some of the patients remain alive years after the treatment. In the most recent trial, 32% of Provenge-treated patients remained alive three years after treatment. Only 23% of placebo-treated patients survived that long.

The approval makes Provenge the first cancer treatment vaccine. It will "re-energize" work in a field that is littered with disappointing failures, says Robert Dreicer, MD, chairman of Cleveland Clinic's department of solid tumor oncology. Dreicer helped run a Provenge clinical trial but has no financial interest in the product.

"If you asked me two years ago if I thought we were on the cusp of a cancer-treatment vaccine, I would have said no -- and I would have been wrong," Dreicer tells WebMD. "Now we are about to see a series of therapeutic vaccines that will not be curative, but which will allow us to manage many advanced cancers in a chronic disease paradigm."

The treatment won't be inexpensive. Industry analysts' estimate of Provenge's cost range from $40,000 to $100,000, with most analysts betting on the high end of the range. And the treatment presents a logistical challenge, as cells taken from patients must be transported to Dendreon facilities, treated with Provenge and tested for purity and potency, and then returned to a doctor for infusion.

Ongoing clinical trials are looking at whether Provenge might have more dramatic effects if given earlier in the course of prostate cancer. One of these studies is giving Provenge to men intending to undergo prostatectomy for prostate cancer that is still confined to the prostate gland. Investigators will examine the removed prostate tissue for signs that Provenge is reducing prostate tumors.

PROVENGE（sipuleucel-T）介绍说明；

附件：http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm210174.htm
FDA批准细胞免疫疗法药Provenge(sipuleucel-T)用于治疗前列腺癌

2010年4月29日美国食品药品监督管理局（FDA）今日批准Provenge (sipuleucel-T)一种新的用于治疗某些晚期前列腺癌患者的药物，该药可通过激发患者自身免疫系统来抵抗这种疾病。Provenge适用于治疗已扩散至人体其他部位并且常规激素治疗无效的无症状或症状轻微的前列腺癌。

在美国，前列腺癌是男性中仅次于皮肤癌的第二常见癌症类型，通常发生于老年男性。根据美国国家癌症研究所（National Cancer Institute）的统计，2009年约有192000个新的前列腺癌病例被诊断出，并且约有27000人死于该病。FDA生物制品评估和研究中心的执行主任Karen Midthun博士表示，“Provenge的获批为目前治疗药物有限的晚期前列腺癌患者提供了一种新的选择。”

Provenge是一种自体源性细胞免疫疗法药（autologous cellular immunotherapy），可激发患者自身免疫系统对前列腺癌作出反应。每剂Provenge均通过一种用于白细胞去除术（leukapheresis）的机器提取患者血液中的免疫细胞而制备的。为增强这些免疫细胞对前列腺癌的反应，这些细胞随后会被暴露于一种在多数前列腺癌中存在的蛋白质，并结合为一种免疫激发物质（immune stimulating substance）。在这个过程之后，患者的自身免疫细胞会返回至其体内以治疗这种前列腺癌。Provenge大约每隔2周静脉注射3剂。

在一项纳入512名激素治疗无效的转移性前列腺癌患者的随机、双盲、安慰剂对照、多中心试验中，对Provenge的有效性进行了研究，该研究显示（接受Provenge治疗的患者较未接受该药治疗者）其总体生存期增加4.1个月。接受Provenge治疗的患者的中位生存期为25.8个月，而与之相对照的未接受该药治疗患者的中位生存期则为21.7个月。

几乎所有接受Provenge治疗的患者都曾发生过某种类型的不良反应。已报告的常见不良反应包括寒战、疲劳、发热、背痛、恶心、关节痛和头痛。大部分不良反应为轻度或中度。在大约1/4接受Provenge治疗的患者中已报告的严重不良反应包括一些急性输注反应和中风。在Provenge组中3.5%的患者被观察到有心血管事件发生，包括出血性和局部缺血性中风，而对照组为2.6%。Provenge由位于Seattle的Dendreon公司生产。