A new study suggests that Viagra—widely known as a treatment for male erectile dysfunction—could also be effective in preventing the spread of cancer. Israeli researchers claim to have identified a biological process through which sildenafil, the active ingredient in Viagra, can reduce the ability of cancer cells to spread throughout the body. This information was reported online by The Times of Israel on Monday (August 3).
The report notes that the study was published in the international scientific journal Cancer Research in July.
According to researchers at Israel’s Weizmann Institute of Science, sildenafil blocks a crucial pathway for cholesterol supply to cancer cells. Cholesterol is an essential component that cancer cells utilize to spread to other parts of the body, a process known as metastasis.
The study was led by Dr. Yarden Ariav. It involved the laboratory of Professor Ayelet Erez at the Weizmann Institute, the laboratory of Professor Eytan Ruppin at the U.S. National Cancer Institute, and physicians and scientists from the Israeli healthcare provider Clalit Health Services and Clalit-Beilinson Hospital.
The research was conducted using mouse cancer models, cultures of cancer cells derived from humans, and health data spanning 20 years from approximately 5 million Clalit members.
The researchers’ analysis revealed that patients who had taken both sildenafil and statins (cholesterol-lowering drugs) for at least six months prior to their cancer diagnosis showed comparatively higher survival rates.
Laboratory experiments focused primarily on triple-negative breast cancer, melanoma, and lung cancer. Professor Ayelet Erez states that data from actual patients aligned with the results observed in mice; similar trends were noted, particularly in cases of lung, colon, and prostate cancer.
According to her, the next phase of the research involves conducting clinical trials on women. She emphasizes that the most critical step now is to conduct a clinical trial using Viagra on women suffering from triple-negative breast cancer.
How does Viagra work?
Sildenafil was originally developed to treat heart disease due to its ability to dilate blood vessels. It later gained recognition as an effective treatment for erectile dysfunction in men and received approval for this purpose in 1998.
In the study, scientists administered the drug to both male and female mouse cancer models as well as to human cancer cells. Using high-resolution cellular imaging technology, they observed that sildenafil rapidly inhibits an enzyme known as phosphodiesterase type-5 (PDE5). This inhibition leads to an increase in the levels of cyclic GMP, a crucial chemical messenger within the cell.
Subsequently, this cyclic GMP blocks a protein responsible for transporting cholesterol into cancer cells. Once the supply of cholesterol is cut off, the cancer cells lose their ability to spread to other parts of the body, resulting in a significant reduction in metastasis.
Professor Erez notes, “We have discovered a new biological pathway and demonstrated how it can be utilized for therapeutic purposes.”
However, the study revealed that the cancer cells did not easily succumb; when the supply of external cholesterol was halted, they began producing their own cholesterol.
To address this, the researchers administered statins—a widely used class of drugs that reduce cholesterol production in the body. According to data from Johns Hopkins University in the United States, more than 200 million people worldwide take statins.
Research has shown that the combined use of statins and sildenafil helps control cholesterol levels and more effectively inhibits the spread of cancer.
Same indications found in health data of 5 million people
Dr. Samah Hayek, a senior epidemiologist at Clalit Health Services, stated that researchers from the Weizmann Institute sought their assistance to compare laboratory findings with data from actual patients.
She explained that the researchers wanted to examine the outcomes for patients who had taken Viagra and statins in the six months prior to their cancer diagnosis.
“We took various factors into account using statistical and epidemiological methods,” Dr. Hayek said. “The results were found to be consistent with data obtained from studies on mice. Thus, by combining laboratory research with real-world patient data, we were able to answer a significant research question.”
Dr. Ido Wolf, Head of the Oncology Department at Tel Aviv Medical Center—who was not involved in the study—noted that this research highlights a crucial yet previously overlooked aspect of cancer biology.
According to him, metastatic cancer cells rely heavily on cholesterol; disrupting the transport of cholesterol into these cells opens up new therapeutic possibilities. The study not only identified a new mechanism but also substantiated it with real-world health data from a large population.
Dr. Wolf states that these results demonstrate the potential for rapidly repurposing widely available and well-established drugs, such as sildenafil and statins, for new therapeutic uses.
Dr. Hayek notes that this exemplifies translational science—an approach that seeks to apply laboratory research to human medical treatment.
According to Professor Erez, cancer treatment requires looking beyond just genetic mutations or the tumor microenvironment; the patient must also be given equal importance.
She points out that factors such as the patient’s diet, level of physical activity, and current medications are significant; treatment plans should be devised by considering the patient as a whole, living being.
