Where are the new low-cost cancer drugs? Do common drugs from the pharmacy represent the future of cancer treatment? The Repurposing Drugs in Oncology (ReDO) project, an international collaboration between Anticancer Fund, Belgium, and US based GlobalCures, finds that existing and widely-used non-cancer drugs may represent a relatively untapped source of novel therapies for cancer.
Currently the main focus in new drug development is on targeted therapies aimed at specific cancer pathways. In spite of major advances, the side-effects and modest effectiveness of such therapies raise concerns; additionally the high cost of these new therapies puts them out of reach for many patients. In contrast, there is strong evidence that some common inexpensive drugs used in the treatment of other diseases (e.g. diabetes, high blood pressure), have anti-cancer effects that can be exploited in combination treatments.
"It really is a case of looking at the cancer treatments in our medicine cabinets," says Pan Pantziarka, lead author of the first two papers to be published by the ReDO project.
Working in the US, Belgium and the UK the ReDO team have drawn up a short-list of drugs with enough evidence to go to clinical trial. Working with leading oncology journal ecancermedicalscience, ReDO is producing a series of scientific papers that explore these drugs in detail -- starting with the drug mebendazole, an over-the-counter treatment currently used for threadworm. The paper cites strong pre-clinical evidence that mebendazole has anti-cancer properties, particularly in colorectal cancer, brain tumours, melanoma and possibly leukemia and bone cancer. The authors conclude that there is sufficient evidence to begin clinical trials now.
"Such promising therapies are often ignored since pharmaceutical companies lack financial incentives to develop them further via proper clinical trials," says Gauthier Bouche, medical director of Anticancer Fund. "The ReDO project was established to find and document such opportunities."
In addition to mebendazole, other high-priority cancer drug candidates include cimetidine (an antacid), nitroglycerin (used to treat angina), itraconazole (a common anti-fungal), diclofenac (an over-the-counter pain killer) and clarithromycin (an antibiotic).
"ecancer is committed to developing affordable cancer care in all emerging countries," says Professor Gordon McVie, of the European Institute of Oncology and ecancer. "We have great pleasure therefore in partnering ReDO in disseminating news from their important and innovative project. A success with even one of their repurposed drugs would have a significant impact on improving cancer care in India, Africa or South America, as well as in the developed world."
However, without industry funding getting these low-cost and relatively non-toxic drugs to trial is a challenge for society. Dr. Vikas P. Sukhatme, co-founder of GlobalCures and professor at Harvard Medical School, describes these drugs as "financial orphans looking for adoption."
"Repurposing these drugs will save money and lives," says Pan Pantziarka. "This isn't just about medical breakthroughs; it's about social necessity worldwide."