U.S. health officials on Friday approved the use of a new HIV drug, made by Johnson & Johnson, in combination with related therapies to help treat patients who do not first improve with other treatment.
The drug, Prezista, is a protease inhibitor designed to treat resistant strains of HIV, the virus that causes AIDS.
The approval marks the New Jersey-based drugmaker's first entry into the $1.5 billion U.S. market for protease inhibitors, a class of drugs designed to suppress the virus and prevent it from replicating.
Also known as TMC114, the drug is given with a low dose of an older protease inhibitor called ritonavir, which slows the breakdown of Prezista in the body, increasing its concentration in a patient's system, the Food and Drug Administration said.
The human immunodeficiency virus that causes AIDS infects close to 40 million people worldwide, with more than 1 million in the United States. The U.S. Centers for Disease Control and Prevention estimates that 40,000 Americans become infected with HIV each year.
While many HIV therapies are now available, AIDS specialists and activists have said resistance to them is becoming a problem because the virus can quickly mutate and current drugs can become ineffective.
TRIAL RESULTS
JP Morgan analyst Michael Weinstein, in a note to clients on Wednesday, forecast Prezista sales of $65 million in the second half of 2006 and peak sales of $800 million to $900 million.
"I really expect it to be used quite widely even with the indication that it has," Dr. Tim Wilkin of Weil-Cornell Medical College, New York, who helped conduct one of the Prezista clinical trials, said in an interview before the approval.
J&J said the drug, which will be taken in combination with other HIV drugs, will have a wholesale cost of $25 a day.
Still, other doctors sounded a more cautious note.
Dr. Steven Deeks, an associate professor of medicine at the University of California, San Francisco, said he plans to delay prescribing the J&J drug for patients who are highly resistant to existing HIV drugs until he can combine it with a second compound that would work for these patients.
He said these drugs need to be partnered with another effective drug. "For many patients with truly highly resistant HIV, there is no drug yet to partner with it," Deeks said in an interview on Friday.
The FDA said it approved Prezista based on two six-month trials that found 70 percent of patients who had tried other therapies improved when they added Prezista and ritonavir to their drug cocktails compared with 21 percent of those who took ritonavir with other protease inhibitors.
In a separate release, Roche Holding AG said the trial showed that its anti-HIV drug Fuzeon, in combination with Prezista and ritonavir, resulted in undetectable virus levels in up to two-thirds of patients who had become resistant to other drugs.
Side effects of Prezista can include diarrhea, nausea and headache as well as mild to serious skin rashes. The risks for patients who have not undergone other treatments first is unknown, the agency said.
J&J must also conduct post-marketing studies, it said.
Prezista is the first of three advanced compounds in J&J's HIV franchise, which aims to combat HIV drug resistance.
Prezista will be followed by TMC125, a non-nucleoside reverse transcriptase inhibitor typically used in combination with other drugs expected to be launched in late 2008.
That will be followed by TMC278, a second non-nucleoside reverse transcriptase inhibitor.
J&J also is studying Prezista in comparison to currently approved protease inhibitors.
Shares in the company were up 66 cents, or 1 percent, at $61.98 in after-hours trade on the Inet exchange after earlier closing up 14 cents at $61.32 on the New York Stock Exchange.
针对抗药病人开发的新的抗艾滋药物
（本文由丁香园网友Victor001翻译并点评）
美国卫生官员周五批准使用一种新的艾滋病病毒的药物，由Johnson开发，结合相关疗法治疗的病人，帮助改善其他治疗。该药即Prezista，一种针对抗艾滋病毒菌株的蛋白抑制剂。新泽西的批准标志着药物制造商首次进入美国15亿美元的蛋白抑制剂市场，该类药物可抑制病毒复制并对抗其作用。食品与药物管理局的人表示，如同已知的TMC114，蛋白抑制剂ritonavir的剂量很低，将会减缓Prezista在体内的降解，从而增加病人的体内浓度。
人类免疫缺陷病毒引起病毒感染在全世界近40万人，100多万在美国。美国疾病控制和预防中心估计，每年40,000人感染上艾滋病毒。虽然有许多艾滋病病毒治疗方法，但专家认为耐受或抵抗正在成为问题。因为这种病毒可以在很短的时间内突变，药物治疗效果很差。
分析师Michael在周三向客户表示，Prezista销售预测2006年下半年可到6500万美元，销售高峰将从8亿上升到9亿。纽约布鲁美国康乃尔大学医学院的Wilkin博士协助进行Prezista的临床试验，他在接受采访时说：“我真希望该药能得到普遍采用，因为该药物起效较慢。”
J&J说，结合其他艾滋病药物，批发成本为每天25美元。 还有其他医生的发言是比较慎重地。史蒂文博士（美国加州大学助理教授）计划对现有的艾滋病药物出现抵抗的患者推迟使用该药物，直到他能符合其他有效的药物为这些患者治疗。他表示，这些药物必须与其他有效药物配伍使用。在周五接受采访时Deeks表示：“许多抗药性强的艾滋病患者还没有真正有效的配伍药物。”
美国食品及药物管理局说，通过对Prezista进行的2次六个月的试验，把Prezista和ritonavir加到鸡尾酒药物发现其中70%的患者曾尝试过其他疗法并且病情得到改善。相比，把ritonavir加到鸡尾酒药物只有21%的人得到改善。
在单独应用中，Roche Holding AG表示，研究显示，抗艾滋病毒药物Fuzeon结合Prezista和ritonavir使用，可使达三分之二对其他药物产生抗药性的病人病毒载量到达检测不到的水平。
Prezista副作用可能包括腹泻、恶心、头痛以及轻微到严重的皮肤出现红疹，而没有经过其它治疗的病人治疗后是否出现这些副作用尚不清楚。
在防止艾滋病毒抗药性方面，Prezista是三个高级化合物中的一种。
预料于2008年底 Prezista将在非核苷反转录酶抑制剂TMC125之后，与其他药物合并使用。这个药物将会是tmc278后第2个非核苷反转录酶抑制剂。
J&J目前正在开展prezista和其他批准的蛋白抑制剂的对照治疗。网络发布消息几个小时后，在纽约证券交易所，该公司股票很快上升。
点评：
J&J开发的Prezista是非核苷类反转录酶抑制剂。
这类药物一般要结合其他的化合物才能更好的发挥作用，是鸡尾酒药物的新的补充。虽然目前最为流行的还是膜融合抑制剂，但是理论上，反转录酶抑制剂的效果也是比较明确的。
唯有多方位的预防，多途径治疗策略才是对抗HIV的出路。
编辑：西门吹血
