经济学人下载:癌症治疗 查理检查站

Science and technology
科学技术

Cancer therapy
癌症治疗

Checkpoint Charlie
查理检查站

A new class of drugs is being deployed in the struggle against cancer
部署新药部队投入抗癌战斗

THE lexicon of oncology is filled with military metaphors: the war on cancer, aggressive tumours, magic bullets.
肿瘤学词典里充斥着军事比喻：抗癌战，侵袭性肿瘤，魔术弹。

And although these are indeed only metaphors, they do reflect an underlying attitude—that it is the clinician's job to attack and destroy his patient's tumour directly, with whatever weapons are to hand.
虽然只是些比喻，它们却凸显出人们对待肿瘤的态度。临床医生的工作就是直接攻击和摧毁病人体内的肿瘤，无论是用什么武器装备。

As in real warfare, those weapons may be conventional, chemical or nuclear.
就像在真实的战场上一样，这些武器可能是常规武器，化学武器，或者核武器。

There is even talk of biological agents, in the form of viruses specifically tailored to seek out and eliminate their tumorous targets.
有时甚至会使用生物制剂，即能找出并消灭肿瘤标靶的特制病毒。

Which is all well and good as strategies go. But as Sun Tzu observed, the wisest general is not one who wins one hundred victories in one hundred battles, but rather one who overcomes the armies of his enemies without having to fight them himself.
癌症治疗和兵法一样好用。但是正如孙子所言，善用兵的将军不是指百战不殆，而是能不战而屈人之兵。

And one way to do that is to get someone else to do your fighting for you.
有个办法就可以做到，那便是让别人帮你战斗。

That, in an oncological context, is where immunotherapy comes in.
在肿瘤学领域，这就需要免疫疗法出山。

Instead of attacking cancer directly, immunotherapy recruits a patient's immune system to do the attacking.
免疫疗法并不直接攻击癌症，而是招募病人的免疫系统来做这件事，最新的方法是解除那些为保护人体在健康时期免受免疫系统伤害而对其进行检查的控制机制。

The latest way of doing so is by removing the controls which keep the immune system in check during times of bodily peace, lest it damage the person it is supposed to be protecting. Such checkpoint-inhibitor immunotherapy has proved itself over the past three years in the treatment of advanced melanoma, hitherto a death sentence.
晚期黑色素瘤目前被视为对病人判了死刑，而过去三年的这类病症相关治疗证明检查抑制剂免疫疗法确实有效。

Now, as a series of papers presented this week to the annual meeting of the American Society of Clinical Oncology, in Chicago, shows, its range is being extended.
现在，在芝加哥举办的美国临床肿瘤学协会年度会议上，研究人员发表一系列论文表明该疗法可以推广到其它肿瘤治疗领域。

More effective versions are being brought to bear on melanoma.
目前更多有效的同类治疗手段正在用于治疗黑色素瘤，

And the whole approach is being tried out—often successfully—on lots of other cancers, including those of the lungs, the kidneys, the bladder, the colon, the stomach, the head and the neck.
这种方法正在经受其它癌症的考验，如肺部、肾脏、膀胱、结肠、胃部、头部和颈部等出现的癌症，并且常常很有效果。

Checkout time
检查时间到

The treatment of melanoma that started the ball rolling employed a drug called ipilimumab.
这种黑色素瘤治疗是研究人员在三年前的协会会议上公布的。

This belongs to a class known as monoclonal antibodies.
它使用一种名为易普利姆玛的单克隆抗体药物。

An antibody is an immune-system protein shaped to lock onto a particular chemical target. And specific varieties of antibody, aimed at specific targets, can be generated from cultures of genetically identical cells created for the task—in other words, cellular clones.
抗体是一种能够锁定特异化学标靶的免疫系统蛋白。不同类型的抗体针对不同的特定性标靶，可以通过培养那些为实现特定功能而出现且具有相同基因的细胞获取，换句话说就是采用细胞克隆的方法。

Ipilimumab locks onto and thus blocks the action of a protein, CTLA-4, which sits on the outer membranes of immune-system cells called T-lymphocytes.
易普利姆玛锁定并抑制CTLA-4的活动，这种蛋白位于T淋巴细胞的细胞膜外层。

These lymphocytes exist to kill body cells that pose a threat, such as cells infected by viruses, and also cancer cells.
这些T淋巴细胞杀死构成威胁的身体细胞，比如被病毒感染的细胞或者癌细胞等。

CTLA-4's role is to calm lymphocytes down and stop them proliferating.
CTLA-4的作用是让淋巴细胞冷静下来，阻止它们增殖。

That is a good thing when there is no threat around.
这在人体未受威胁时是件好事，但是有些癌细胞非常善于躲避免疫系统。

But some cancer cells are skilled at hiding from the immune system, so a drug that switches CTLA-4 off can unleash lymphocytes in circumstances when they are needed but otherwise unavailable.
在需要淋巴细胞活动却无法激活的情况下，一种关闭CTLA-4功能的药物可以解放更多的淋巴细胞。

Ipilimumab's success has spurred the development of further antibodies that work in similar ways.
易普利姆玛的成功激励研究人员深入研究有着类似工作机制的抗体。

Nivolumab and lambrolizumab gum up another surface protein, PD-1; and a fourth, so new that it still goes by its laboratory identifier of MPDL3280A, binds to PD-L1, a protein that would otherwise help PD-1 to do its job.
Nivolumab和lambrolizumab扰乱另一种表面蛋白PD-1。第四种蛋白最近才发现，还使用着实验室标识符MPDL3280A，它可以绑定到PD-L1上，而PD-L1会反过来协助PD-1蛋白完成任务。

Though they have slightly different modi operandi, all four antibodies work by shutting down biochemical checkpoints that limit the proliferation of lymphocytes.
尽管方式稍微不同，四种抗体采取关闭生物检查站，解除淋巴细胞扩散限制的方法，

Hence the name checkpoint inhibitors.
因此得名检查抑制剂

In the original trials of ipilimumab, 11% of patients responded.
易普利姆玛在最初进行试验时，有11%的病人对药物产生反应。

That might not sound many, but those who did respond often did so strongly—surviving in some cases for years with no evidence of disease.
虽然人数不是很多，但这些病人的反应很强烈。有些人可以存活几年而没有疾病特征。

Ipilimumab's successors have pushed the response rate up while maintaining the long-term benefits.
易普利姆玛的后续制剂提高了反应比例，同时维持长期效果。

A trial of nivolumab, led by Mario Sznol of the Yale Cancer Centre, showed a success rate of almost a third in a group of 107 melanoma patients, when success was defined as a tumour shrinking by 30% or more.
耶鲁大学癌症中心Mario Sznol 对Nivolumab进行了试验，按照肿瘤缩小至少30%的标准，参与该试验的107名黑色素瘤病人中有三分之一取得了良好的治疗效果，

The median survival time of these successes has so far been 16.8 months, quite a gain over the nine months that might have been expected for such people just a few years ago.
目前存活时间的中位数为16.8个月，这要比前些年对这类病人存活期的预期增加了9个月，已经算相当长了。

Lambrolizumab, too, looks promising.
Lambrolizumab也很有前景。

Antoni Ribas of the University of California, Los Angeles, and his colleagues reported to the meeting that the tumours of more than a third of the 135 advanced-melanoma patients whom they had treated with it have shrunk.
洛杉矶加利福尼亚大学的Antoni Ribas及其同事在会议上报告称，135名接受Lambrolizumab治疗的黑色素瘤病人中，有超过三分之一的肿瘤缩小了。

Some of these people had previously been treated, unsuccessfully, with ipilimumab, confirming that the two drugs really do work in different ways.
有些人之前接受ipilimumab治疗却没有成效，证明了这两种药物确实有着不同的工作机制。

Those separate modes of action were also confirmed by work announced to the meeting by Jedd Wolchok of the Memorial Sloan-Kettering Cancer Centre, in New York.
两种制剂相互独立的作用机制也由Jedd Wolchok向大会所做的工作汇报证明。

He and his colleagues reported that a combination of ipilimumab and nivolumab causes faster and more complete responses than either does on its own. So far, they have treated 52 people.
Jedd来自纽约斯隆–凯特林癌病中心，他和同事们称ipilimumab和nivolumab结合使用比单独使用产生更快更彻底的效果。

The tumours of around three-quarters of these patients began shrinking in the first 12 weeks of treatment.
目前他们治疗了52位病人，约有四分之三的的肿瘤在治疗初的12周内开始缩小，

In a third of cases tumours shrank by 80% or more in that period and in 90% the patient was continuing to respond at his last check-up.
同时有三分之一的肿瘤缩小了至少80%。在最后一次的检查中，这种治疗对90%的病人继续有效。

This, then, is good news for those with melanoma.
这对于患有黑色素瘤的病人是个莫大的好消息。

But the most intriguing paper of the series was delivered by Roy Herbst, who also works at Yale.
然而这些论文中最令人激动的要数同在耶鲁工作的Roy Herbst所发表的论文。

He and his colleagues are testing MPDL3280A in a trial open to people who have any type of metastatic or otherwise incurable tumour—those, in other words, for whom established treatments offer no hope.
他和同事们在一轮实验中测试MPDL3280A，并且面向所有患有任何转移性或者不可治愈肿瘤的人，换句话说，这些病人的肿瘤是目前成熟的治疗手段所不能治疗的。

Preliminary results suggest a fifth of the 140 patients in this trial are responding. And, as in the case of Dr Wolchok's work, these responses are long-lasting.
该实验的初步结果显示140名病人中有五分之一产生反应，并且这些反应长期持续，恰如Wolchok博士研究中观察到的那样。

The crucial point in the MPDL3280A trial is that those who have responded have a range of cancers—not just melanoma.
MPDL3280A试验的关键点在于那些产生反应的病人患有的癌症多种多样，不局限在黑色素瘤。

What was once a treatment specifically for melanoma now looks as if it might work for at least some cases of half a dozen common cancers.
曾经专门用于黑色毒瘤的治疗现在看似至少对六种常见肿瘤的部分病例起效。

If such results are confirmed by future studies, a new front will have opened in the war on cancer.
这一结论如果能在未来的研究中得以验证，抗癌战争就开拓了新前线。

Moreover, the troops on this front will be not untested conscripts but confederates who are familiar with the enemy and just needed a little encouragement to join the battle.
此外，守在前线的部队不是没有经验的新兵，他们对敌人十分了解，只需要一点点鼓励参加战斗，

Sun Tzu would surely have approved.
而孙子必定会批准下命令。