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腾讯登录FDA委员会：安全性问题不妨碍赛诺菲MS药物Lemtrada的获批
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FDA顾问委员会周三举行会议，认为赛诺菲（Sanofi）开发的实验性多发性硬化症（MS）药物Lemtrada的安全性问题，并不妨碍（preclude）该药的批准，但该委员会对相关临床研究的质量表示了担忧。
该委员会以17:0，1票弃权的投票结果认为，Lemtrada潜在导致癌症及其他严重疾病的安全性问题，不能成为阻止MS患者获得该药的一个理... |
该委员会以17:0，1票弃权的投票结果认为，Lemtrada潜在导致癌症及其他严重疾病的安全性问题，不能成为阻止MS患者获得该药的一个理由。
然而，该委员会大多数成员认为，Lemtrada相关临床研究不足且未良好控制（well-controled），称尽管Lemtrada似乎对复发型MS患者有效，但并未被证明能够帮助阻止残疾。
该委员会主席、弗吉尼亚大学医学院Nathan Fountain医师认为，对于某些患者，Lemtrada可能是适合的。
上周，FDA审查员对Lemtrada潜在导致系列自身免疫性疾病及潜在引发甲状腺癌、皮肤癌、乳腺癌的安全性问题表达了严重关注。
顾问委员会成员认为，尽管这些风险很大（substantial），但对于某些难以治疗的MS患者而言，可能是值得的，因为复发型MS实在是一种非常糟糕的疾病。
多发性硬化症（MS）是一种慢性、自身免疫性疾病，在全球范围内患者总数超过250万人，在美国多达50万患者。该病可引起肌肉无力、疼痛、言语和认知困难。
Lemtrada旨在用于治疗复发缓解型多发性硬化症（relapsing remitting multiple sclerosis，RRMS），这是多发性硬化症中的最常见形式。
Lemtrada于今年9月获欧盟批准，用于活动性复发缓解型多发性硬化症（RRMS）成人患者的治疗。
根据汤姆森路透数位分析师预测，若Lemtrada获FDA获批，预计截止2018年的销售峰值仅为7.52亿美元。
FDA并非一定要遵循其顾问委员会的建议，但通常都会这样做。
2项III期临床试验表明，在减少年度复发率方面，Lemtrada显着优于活性对照药物Rebif，同时Lemtrada治疗组中有更多的患者在2年内无复发。
但这2项研究中，研究人员和患者知道其正在接受哪种药物治疗，因此提出了相关疑问，即这些研究结果是否存在偏颇（biased）。但赛诺菲认为，由于这2种药物给药的方式本身就不同，所以很难伪装患者接受哪一种药物治疗。
Lemtrada是一种单克隆抗体，被认为能够选择性消耗T细胞和B细胞，同时保留免疫系统中的其他抗感染成分，该药的给药方式为静脉给药5天，1年后给药3天。
如果获批，Lemtrada将与百健艾迪（Biogen Idec）的Tysabri展开激烈竞争，该药是市面上最有效的多发性硬化症（MS）治疗药物，但可能引发一种潜在致死的脑部感染，即进行性多灶性白质脑病(PML)。
这种风险，已将Tysabri的使用限制至经其他MS药物治疗失败的患者群体，若Lemtrada获批，也可能被限制至这一患者群体。
大多数MS药物为注射或输注给药，目前MS市场正逐渐走向口服治疗药物，其中百健艾迪（Biogen Idec）最近推出的Tecfidera有望成为市场的领导者，年销售峰值将超过30亿美元。
口服药物预计最终将从注射药物中夺取市场份额，其中包括梯瓦（Teva）的Copaxone。
关于Lemtrada：
Lemtrada是一种单克隆抗体，靶向于CD52，这是一种位于T细胞及B细胞上的蛋白。健赞认为，该药能够减少MS疾病的活动，通过抗炎作用，有助于再次平衡（rebalance）免疫系统。
原文链接：
FDA panel says safety issues do not rule out Sanofi MS drug approval
(Reuters) - A federal advisory panel said safety issues do not preclude approval of Sanofi SA's experimental multiple sclerosis drug Lemtrada on Wednesday, but voiced concerns about the quality of clinical studies.
An advisory panel to the Food and Drug Administration voted 17 to 0, with one abstention, on Wednesday that the drug's potential to cause cancer and other serious conditions was not a reason to prevent patients from gaining access to it.
However, a majority of panel members believed Sanofi's studies were not adequate and well-controlled, and they said that while it appeared to be effective in patients with relapsing MS it had not been proven to help against disability.
"Do I want to take this drug? No way!" said Dr. Nathan Fountain of the University of Virginia School of Medicine and the panel's chairperson. But for some patients, he said, it could be appropriate. "I wouldn't want to deny those people," he said.
The panel's recommendation follows an initial report last week by reviewers for the FDA, who raised grave concerns about the drug's potential to cause an array of autoimmune conditions, in which the body mistakenly attacks its own cells, as well as its potential to cause thyroid, skin and breast cancer.
Advisory panelists, who met in Silver Spring, Maryland, said the risks could be worth it for some difficult-to-treat patients.
"The risks are very substantial, but this is a really bad disease," said Dr. Paul Rosenberg of the Johns Hopkins University School of Medicine.
Multiple sclerosis is a chronic, autoimmune disease that affects more than 2.5 million people worldwide and up to 500,000 in the United States, according to the Multiple Sclerosis Foundation. It can cause muscle weakness, pain, and speech and cognitive difficulties.
Lemtrada is designed to treat relapsing remitting multiple sclerosis, the most common form of the disease, in which flare-ups are followed by periods of recovery.
The drug, which was approved in Europe in September, was at the heart of Sanofi's lengthy, $20.1 billion takeover battle for Genzyme Corp., which developed the drug. Sanofi finally acquired Genzyme in 2011.
As part of the takeover deal, Genzyme shareholders received contingent value rights, known as CVRs, entitling them to future payments of up to $14 a share if certain goals were met, including approval for Lemtrada.
The price of the CVRs has fallen 67 percent to 66 cents since the FDA posted its review last week.
If Lemtrada, also known as alemtuzumab, is approved, it is expected to generate peak sales of $752 million by 2018, according to seven analysts polled by Thomson Reuters.
The FDA is not bound to follow the advice of its advisory committees but typically does so.
Two late-stage clinical trials showed that patients taking Lemtrada were significantly less likely to experience a relapse over the course of two years than patients taking Rebif, a standard therapy made by EMD Serono, a subsidiary of Merck KGaA and Pfizer Inc.
But patients and investigators knew which treatment they were getting, raising questions as to whether the results could have been biased. Sanofi argued that it was difficult to disguise who was taking which treatment given the differences in how they are dosed.
Lemtrada is a monoclonal antibody that is thought to selectively deplete T and B cells, while sparing other infection-fighting elements of the immune system. It is given intravenously for five days and then for three days a year later.
If the drug wins approval it would likely compete most closely with Biogen Idec Inc's Tysabri, which is one of the most effective drugs for multiple sclerosis on the market but can cause a potentially fatal brain infection known as PML.
That risk has limited Tysabri's usage to patients who have failed other treatments -- a group which Lemtrada, if approved, would also target.
Most MS drugs are either injected or infused. The market is increasingly moving toward oral treatments, of which Biogen's recently launched Tecfidera is expected to be the market leader, with peak annual sales of more than $3 billion.
Oral drugs are expected to eventually take market share from injectibles, which also include Teva Pharmaceutical's Copaxone.
来源：生物谷
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