经济学人下载:癌症治疗 即将实现对症下药

Cancer therapy
癌症治疗

Taking aim sooner
即将实现对症下药

If personalised medicine is to achieve its full potential, it should be used earlier on in clinical trials
若想让个体化药物发挥最大潜力，那就应该尽早将它投入临床试验。

Jun 9th 2011 | from the print edition

ONE of the prospects supporters of the Human Genome Project held out was personalised medicine. Knowing which genes were involved in a particular patient’s disease would allow drugs to be deployed with greater precision. That is starting to happen in the field of cancer. Several targeted therapies, aimed at specific cancer-causing mutations, including Gleevec for chronic myelogenous leukaemia and Herceptin for some types of breast cancer, have been spectacularly successful. Yet in most cases of cancer doctors still base their treatment on where in the body a tumour has sprung up, rather than on which molecular aberrations have caused it.

人类基因组计划支持者认为该计划的前景之一就是个体化药物。通过了解哪些基因与特定病人的疾病存在关联，会使药物的使用更加精确。在癌症领域，这种情况即将成为现实。几种针对特定致癌突变的靶向疗法——包括治疗慢性髓细胞性白血病的格列卫和治疗多种类型乳癌的赫塞汀——所展现出的治疗效果令世人瞩目。而在癌症的大多数病例中，医生们的治疗仍然基于人体中肿瘤出现的位置，而不考虑究竟是哪几种分子畸变导致了肿瘤的发生。

The same is true of medical researchers recruiting volunteers for clinical trials, especially those known as phase I trials, in which a new drug is tested on people for the first time. Participants in such trials are often those whose tumour has spread beyond its original site, and will probably prove fatal. Usually, they have tried all proven therapies, to no avail. Their precarious condition means they are rarely accepted for phase II and III trials, which are more complicated and extensive.

对于招募临床试验志愿者，尤其是所谓的第一阶段试验（在该阶段，人们要接受新药的第一次人体试验）志愿者的医疗研究员来说，情况也同样如此。该阶段试验的参加者通常是那些肿瘤发生扩散而远离初始位置的人，他们也将因此而有性命之忧。一般来说，他们已然尝试过所有经过验证的疗法，却徒劳无功。他们危急的病情意味着只有少数人能接受更为复杂和广泛的第二和第三阶段试验。

Oddly, though, even if the drug being tested is a targeted therapy the tradition in phase I trials has been to gather together patients with, say, lung cancer and assume that all carry the relevant mutation. That is because such trials are concerned mainly with testing a drug’s safety, not its efficacy. The volunteers are usually happy to go along with this. But the odds are not good. On average, fewer than 5% of participants in phase I trials respond successfully to the treatment.

但是令人感到奇怪的是，即便所试验的药物是一种靶向治疗药物，第一阶段试验的传统也一直是招募病人，比如肺癌患者，并假定他们所有人都携带相关的突变体。那是因为这些试验主要关注点在于测试药品的安全性，而非有效性。志愿者通常愿意从头到尾全程配合，但是效果仍不甚理想。平均来说，在第一阶段试验中只有不到5%的参与者经过治疗后病情大有起色。