Old medicines getting new uses
A computer program that pairs gene information with drug data may help resurrect old medicines for new uses, including an over-the-counter ulcer pill that may be used to treat lung cancer, Stanford University scientists said.
By searching through a National Institutes of Health database that catalogs the results of genomic studies, researchers matched symptoms of diseases with the effects of drugs, yielding 1,000 potential new treatments, said Atul Butte, the study's lead researcher. The scientists described their work in two reports published in the journal Science Translational Medicine.
The system, which correctly matched current drugs with the diseases they treat, also suggested Tagamet, a nonprescription ulcer medication, may have use in treating lung cancer, and Topamax, an anti-seizure medicine sold as generic topiramate, might treat a type of bowel disorder. Finding new uses for old drugs could become much easier using the approach, Butte said.
“If there are additional uses for drugs coming off patents, one could be thinking creatively, how do we find the value in that,” Butte, the chief of divisions of systems medicine at Stanford's School of Medicine near Palo Alto, California, said in an interview.
It takes an average 15 years and about $1 billion to bring a single new drug to the market, researchers said in one of the reports. So-called repurposing of old drugs can cut that cost because drugmakers wouldn't have to do the toxicity tests required in early development.
Butte's team focused on 100 diseases and 164 generic drugs, which yielded about 1,000 potential treatments, Butte said. The matchmaking method provided possible therapeutic drug-disease relationships for 53 of the 100 diseases, he said. Cancers of the skin and stomach showed the most matches, according to his study.
Topiramate was tested in rats after the program proposed its use as a treatment for inflammatory bowel disease. After administering the drug to the animals with the disease's symptoms, topiramate was effective, sometimes even better than the standard treatment, prednisolone.
That result was compelling, said Pankaj Agarwal, director of computational biology at London-based Glaxo, in an interview.
“The impact of repurposing drugs would be huge,” said Agarwal. “If you find a new use for a drug that's already on the market and somebody sponsors it, you wouldn't have to go through safety and have a new indication within three to five years.”
Cimetidine, the generic form of Tagamet, was targeted by the system for its potential for lung cancer, and was shown to slow tumor cell growth in mice, according to one report.
“Unless someone focuses on this, the additional uses are never going to be captured,” Butte said. “Companies have to get creative and remarket and re-brand these to tests in clinical trials.”