Does personalized medicine cut the mustard when it comes to treating cancer? Richard Smith, a former editor of the British Medical Journal, believes that it does not. Using the mustard metaphor, he shows how personalized medicine undermines the pharmaceutical industry’s profits. If the one-size-fits-all approach to prescribing cancer drugs were abandoned, drug companies would be forced to change their business model, most notably by increasing prices radically — or stop producing the drugs altogether.
In pharmacogenetics (or pharmacogenomics), genetic typing is used to determine a patient’s likely response to drugs, and to tailor the pharmaceutical regime accordingly.
In oncology, this means adjusting treatment based on the cancer’s sequenced genome, which differs from that of the patient’s normal cells. It might be possible, for example, to identify patients who are genetically programmed to respond more quickly to chemotherapy, and thus to prescribe lower dosages that allow them to avoid the treatment’s worst side effects.
This approach is crucial in oncology, given that cancer varies widely, even in patients with the same diagnosis. After sequencing 50 patients’ breast cancers, one group of researchers found that only 10 percent of the tumors had more than three mutations in common.
Likewise, an analysis of biopsies conducted on four patients with kidney cancer showed that a single tumor can have many different genetic mutations at various locations. Two-thirds of the genetic faults identified were not repeated in the same tumor, let alone in any other tumors that appeared elsewhere in the patients’ bodies. A pharmacogenomic drug that targets one mutation may not work on others.
If a pharmaceutical company treats 100 patients for ￡100 each, it makes ￡10,000. However, if only 10 of those patients — 10 percent of tumors — are genetically programmed to benefit from the drug, insurers or national-health systems will want to pay only for those patients, reducing the company’s income by 90 percent. This is where the mustard metaphor comes in.
According to Smith, drug companies are like mustard makers. They make most of their money from patients who do not benefit from the drugs that they provide, just as mustard makers profit primarily from what diners leave on their plates. Stratified or personalized medicine will require drug companies to raise their prices significantly in order to offset losses from the reduction in portions.
In fact, this is already happening. A new personalized drug for cystic fibrosis, Kalydeco, is highly effective, but only in the 4 percent of patients who have a particular genetic mutation. As a result, one year of treatment costs US$294,000. Likewise, Xalkori is being made available for US$9,600 per month, because the drug’s target population — patients whose lung cancers have a certain mutation — comprises fewer than 10,000 patients.
In the UK, the National Health Service deemed the personalized cancer drug Herceptin too expensive, until a public outcry forced the NHS to reverse its position. However, in an age of austerity, will the authorities do so again?
By restricting access to the rich and the well insured, rising drug costs could exacerbate growing inequality in many countries. As the healthcare ethicist Karen Peterson-Iyer has pointed out: “From the standpoint of justice, one of the most disturbing possibilities raised by pharmacogenetics is that it will further entrench the already deep socioeconomic divisions that characterize modern US society.”