Rare Cancer Could Be Subject of ‘Drug Repurposing’

Rare cancers exhibit the characteristic of developing a resistance to chemotherapy drugs, including blood cancers as well as some breast, ovarian, lung, and lower gastrointestinal cancers. A recent study has shown that this resistance could be reversed. 

Scientists at the University of Pittsburgh Cancer Institute (UPCI) took part in screening a library of FDA-approved anti-cancer drugs and discovered that these older drugs could provide hope for patients with certain rare drug-resistant cancers. Their study will be published in the Feb. 15 issue of Cancer Research.

The use of these older drugs to treat the rare cancers is known as "drug repurposing," which is further described by the study's lead author, Anette Duensing, MD, who is an assistant professor of pathology at UPCI. "It is an increasingly promising way to speed up the development of treatments for cancers that do not respond well to standard therapies," she said in this EurekAlert! article.

The study incorporated the screening of 89 FDA-approved anti-cancer drugs while focusing on treatment options for gastrointestinal stromal tumors. As mentioned earlier, gastrointestinal cancers are among those resistant to standard therapies. There are approximately 5,000 cases annually. Patients are typically treated with the drug Gleevec, but half of them become resistant to the drug within the first two years of treatment.

More information about cancer multidrug resistance can be found in this Nature Biotechnology journal submission.

After testing gastrointestinal cancer's response to the 89 drugs, the researchers found that the candidates that demonstrated effectiveness were a member of two major drug classes known as inhibitors of gene transcription and topoisomerase II inhibitors. They then selected two compound drugs of these classes to test their effectiveness on the gastrointestinal stromal tumors. Gene transcription inhibitor mithramycin A and topoisomerase II inhibitor mitoxantrone both demonstrated effectiveness in lab tests when fighting the tumors.

This process of drug repurposing has shown successful trials in this study, which is very promising for future research because cancer treatment can undergo clinical trials with older drugs that may be effective instead of waiting for the development and approval of a new drug.

To read more about drug repurposing, visit this EurekAlert! article.