Beta-blockers, commonly used to slow down heart rate, seem to yield surprising benefits for the treatment of melanoma.
Immunotherapy works by changing the patients' immune system and enabling it to better detect and attack malignant cells. It is seen by medical professionals as one of the newest and best forms of melanoma treatment.
But many people still do not benefit fully from immunotherapy. The research community is now hard at work trying to figure out the most effective combination of immunotherapies, as well as the best ways to avoid its side effects and maximize its benefits.
New research may bring us closer to such benefits. Scientists at Penn State College of Medicine in Hershey — led by Dr. Todd Schell, a professor of microbiology and immunology — investigated the effect of combining beta-blockers with immunotherapies and found that the drugs boosted the impact of immunotherapy on advanced melanoma.
"Beta-blockers slow your heart rhythm, but they can also affect immune cells and improve immune function," Dr. Schell explains.
Additionally, given the fact that beta-blockers are often used to treat stress — known to interfere with how well a patient responds to cancer treatment — the scientists were keen to study the common drugs.
"We wanted to see if there would be a correlation between the beta-blockers patients were taking for another condition and their response to immunotherapy," Dr. Schell adds.
To this end, he and his colleagues examined the data available on patient survival rates and then carried out experiments in mice. The findings were published in the journal OncoImmunology.
Pan beta-blockers boost immunotherapy
Dr. Schell and team examined 195 people whose melanoma had metastasized and who received immunotherapy between the years 2000 and 2015.
Of these patients, 62 were also taking beta-blockers — either beta-1 selective blockers, or so-called pan beta-blockers such as propranolol.
The researchers looked at survival rates, comparing those of the patients taking the two kinds of beta-blockers with those of the patients who did not take beta-blockers.
The analysis revealed a dramatic difference in survival rates between the people who took pan beta-blockers and those who did not take beta-blockers at all.
Specifically, after 5 years of immunotherapy combined with pan beta-blockers, 70 percent of the patients survived, whereas only 25 percent of those who took beta-1 selective blockers or no beta-blockers survived after that same period of time.
To further substantiate their preliminary findings, the team tested the effect of propranolol in a mouse model of melanoma. They found that propranolol in combination with immunotherapy inhibited tumor growth and improved survival significantly.
The benefits of prescribing beta-blockers
"The type of beta-blocker we found to be effective against melanoma — pan beta-blockers — was actually the least prescribed," Dr. Schell comments.
"Most patients are either prescribed beta-1 selective blockers or are not taking beta-blockers at all," he continues. "This means there's a large population of patients who may be eligible to take pan beta-blockers while being treated with immunotherapy."
"And because beta-blockers are already FDA approved, it's something we know is safe and can be very quickly implemented in patient care," Dr. Schell says.
Study co-author Dr. Joseph Drabick, a professor of medicine at Penn State College of Medicine, also comments on the findings.
"The benefit of this is that beta-blockers already have a long history of safety in people, and they're cheap and generic [...] And now they have the potential to augment some of these newer immunotherapy drugs to help people with cancer."
Dr. Joseph Drabick