With the arrival of two revolutionary treatment strategies, immunotherapy and personalised medicine, cancer researchers have found new hope -and a problem that is perhaps unprecedented in medical research.
There are too many experimental cancer drugs in too many clinical trials, and not enough patients to test them on. The logjam is caused partly by companies hoping to rush profitable new cancer drugs to market, and partly by the nature of these therapies, which can be spectacu larly effective but only in select patients.
In July, an expert panel of the US Food and Drug Administration (FDA) approved a groundbreaking new leukaemia treatment, a type of immunotherapy . Firms are scrambling to develop other drugs based on using the immune system itself to attack cancers. Many of these experimental candidates in trials are quite similar. Yet each drug company wants to have its own proprietary version, seeing a potential windfall if it receives FDA approval.
As a result, there are more than 1,000 immunotherapy trials underway , and the number keeps growing. “It’s hard to imagine we can support more than 1,000 studies,“ said Dr Daniel Chen, a vicepresident at Genentech, a bio technology company .
In a commentary in the journal `Nature’, he and Ira Mellman, also a vice-president at the company , wrote that the proliferating trials “have outstripped our progress in understanding the basic underlying science“.
“I think there is a lot of exuberant rush to market,“ said Dr Peter Bach, director of the Center for Health Policy and Outcomes at Memorial Sloan Kettering Cancer Center, “ And we are squandering our most precious resource -patients.“
Take melanoma: There are more than 85,000 cases a year in the US, according to Dr Norman Sharpless, director of the Lineberger Comprehensive Cancer Center at the University of North Carolina. Most melanomas are cured by surgery, leaving about 10,000 patients who have had relapses and could be candidates for an experimental treatment. But nearly all will be treated by doctors outside of academic medical centres, who are not part of the clinical trials network and so do not offer patients experimental treatments.
Companies therefore must compete for the few patients with relapsed melanoma who are at centres offering clinical trials. Many end up struggling to find enough subjects to determine wheth er a treatment actually works -and if so, for whom.
The problem is that many of the trials are uninteresting from a scientific view, said Dr Roy Herbst, the center’s chief of medical oncology . The companies sponsoring these trials are not addressing new research questions, he said; they are trying to get proprietary drugs approved.
Trials involving limited numbers of patients can be perilous. In tiny studies, serious side effects can be missed, said Dr Scott Ramsey , an oncologist at the Fred Hutchinson Cancer Research Center, US.