New drugs target cancer
A new generation of cancer drugs has been garnering attention and, while they are far from a cure-all, they are likely another step in the right direction toward solving the very tricky puzzle that most forms of the disease present to biomedical researchers.
The majority of these new drugs are considered “targeted therapies,” in that they take aim at the genetics of a patient’s cancer instead of simply attacking it very broadly. These drugs anticipate the genetic mutations that can make a cancer so difficult to combat, typically acting to slow tumor growth by inhibiting a protein essential to that process. Other targeted therapies actually cause cells to commit suicide (as they normally would), instead of growing at an unchecked rate.
So far, the clinical trials for these genetically angled treatments have been promising, if not revolutionary. Patients treated with these newest drugs are out-surviving those who receive conventional measures by months — which, although not a great span of time, does offer hope. Accordingly, leading cancer centers are now using genotyping technology to uncover the genetic profiles of a cancer in order to target treatments correctly.
In the case of cancer mutations that haven’t yet been targeted by one of these new drugs, another successful tack is that of immunotherapy. Two drugs — one of them the 2010 approved prostate cancer vaccine, Provenge — aim to bolster a cancer patient’s immune response. Yet Provenge’s efficacy remains uncertain, and the other newly developed immunotherapy drug — ipilimumab, used against melanoma — has been effective in only 10 percent of patients.
Dr. Dennis Powell, former director of oncology chemistry at Wyeth and an expert on targeted cancer therapy, points out some of the obstacles that any researcher will face in this area. “Targeted therapy holds the promise of inhibiting specific cancer pathways while minimizing toxicity,” he says. “Such therapies often do well in initial patient treatment for specific cancers. However, this reliance on focused targets increases the chance that resistance and mutation of those targets can arise quickly and, unfortunately, many of the single agent targeted therapies do not produce durable long lasting results.”
For more on the frustrating shape-shifting nature of cancer, we recommend ACSH’s Dr. Bloom’s look at the topic from earlier this year.
