About 860 cancer drugs are being tested in clinical trials, according to the pharmaceutical industry’s main trade group. That is more than twice the number of experimental drugs for heart disease and stroke combined, nearly twice as many as for AIDS and all other infectious diseases combined, and nearly twice as many as for Alzheimer’s and all other neurological diseases combined.
But for all the industry’s spending and effort, only a trickle of new cancer drugs make it to market. Last year there were two, and this year there has been only one.
And even some of those drugs offer only a few months at most of extra life or tumor stabilization despite prices that often reach thousands of dollars a month. The drug Tarceva, which costs about $3,500 a month, was approved as a treatment for pancreatic cancer because it improved survival by 12 days.
The battle to treat cancer has become, as a commentary in a leading journal put it, a “grinding war of the trenches.”
Why? Experts say the same factors that attract drug companies to the cancer business help explain the slow progress.
Cancer is a lot more complex than simply blocking one or two pathways in most cases. CML and GIST are two such examples, but lung cancer may have 200 pathways that over-express protein tyrosine kinase, but the big question is which ones are constituitively active, ie are aberrant?
Not every cancer patient is the same. If you look at pairs of patients with breast, lung or prostate cancer, for example, they may be very different on the molecular level and thus what works for one, may not work for the other.
We have a long way to go before we even begin to scratch the surface and achieve more than small incremental improvements in survival. A greater understanding of the science and biology of the diseases is important but there is still so much that we don't even know and many drugs and billions of dollars in research will go by the wayside along the journey.