Rare Daily Staff
The class of erectile dysfunction drugs that include Viagra, Cialis, and Levitra, known as PDE5 inhibitors could be enlisted to treat rare cancers, according to a study published in the open access journal, ecancermedicalscience.
Researchers at the Repurposing Drugs in Oncology Project, or ReDO, an international collaboration between the Belgium-based Anticancer Fund and USA-based GlobalCures produced the study. The Anticancer Fund’s mission is to identify commonly available and inexpensive approved drugs that have the potential to be repurposed as life-saving cancer therapies.
In their paper, the researchers reported that PDE5 inhibitors show a wide range of mechanisms of action in different cancer types, such as glioblastoma multiforme, a rare disease where clinically meaningful advances are desperately needed.
“Checkpoint inhibitors have radically altered the landscape in oncology, but there remain significant challenges in terms of increasing the number and duration of responses,” said Pan Pantziarka. “Emerging evidence, summarized in this paper, suggests that PDE5 inhibitors may be one mechanism for achieving this. It would be ironic if the key to improving outcomes from some of the most expensive drugs in oncology comes from repurposing some of the cheapest non-oncology drugs.”
The paper also explores the issue that finding new agents able to cross the blood-brain-barrier is a challenge which severely limits the range of drugs available to treat brain tumors. There is some evidence that drugs not currently licensed for cancer treatment like the PDE5 inhibitors, are able to increase permeability so that drug delivery to brain tumors is improved, potentially opening the door to new therapeutic options for patients.
The paper includes a broad range of data, pre-clinical and clinical, has been summarized and presented to make the case that these commercially available and widely used PDE5 inhibitors are very strong candidates for repurposing as anticancer agents. These low-cost, low-toxicity drugs show potential to be included with current and emerging standard of care treatments in oncology.
The researchers hope that the paper will bring the potential of this class of drugs to the attention of more clinicians and researchers engaged in clinical trials. A number of small, early-stage trials are on-going, but the ReDO group believes that it is time for much larger efficacy trials to begin so that the promise of these cheap repurposed medications can be fully realized.
April 12, 2018