Women treated for melanoma die twice as often as males when given two immunotherapies at once, says new study.

Checkpoint inhibitors, a type of cancer immunotherapy, have changed cancer treatment. It’s a novel technique to combat the disease by allowing the immune system to take over. However, the medication does not cure every patient, and it can have serious, even life-threatening side effects in some. 

According to new research, one group of patients may be at higher risk. Women with advanced melanoma are twice as likely as males to die when treated with the same combination of checkpoint inhibitors, according to the findings, which were published in JAMA Network Open on December 2nd.

“This is the first large population-based study that demonstrates a significant difference in outcomes for women treated with two checkpoint inhibitors at the same time,” said Dr. Grace Lu-Yao, senior author of the study.

“Are women more likely to die because the therapy isn’t working, or because of side effects? We don’t know yet, but this is a powerful signal in real-world data that we need to investigate further,” Dr. Lu-Yao added.

The immune systems of men and women differ slightly. Women, for example, have a higher risk of auto-immune illnesses than men, but they also have stronger immunological responses to infection. Despite these well-documented inequalities, men continue to outnumber women in clinical studies. These trials’ findings, which were considered to be applicable to women, may not be.

Dr. Lu-team Yao’s wanted to see if men and women who had melanoma and were treated with checkpoint inhibitors had the same results. The researchers looked at health information from cancer patients in a nationwide database called SEER (Surveillance, Epidemiology, and End Results), which was connected to Medicare files.

They looked examined data from 1,369 people who had advanced melanoma between 1991 and 2015. One or more checkpoint inhibitors, such as pembrolizumab, nivolumab, or ipilimumab, were used to treat the patients.

There were no changes in survival between men and women treated with a single checkpoint inhibitor, according to the researchers.

However, Dr. Lu-Yao and her colleagues discovered that when the checkpoint inhibitors nivolumab and ipilimumab were combined, the risk of death was 2.06 times higher for women than for males.

The death rate for both men and women using PD-1 inhibitors was 40% at the start. For individuals receiving anti-PD1 and anti-CTLA-4 therapy in combination, the rate remained at 40% for men but increased to 65% for women.

Despite mounting evidence that sex may have a role in affecting pharmacological effectiveness, sex differences between men and women are rarely investigated. This lack of focus on the relationship between sex and the efficacy of ICI-based immunotherapy treatments could have serious ramifications, especially since these medicines are linked with high toxicity and treatment costs.

“This data is a wake-up call based on the experience of hundreds of patients on these drugs,” said Dr. Lu-Yao.

“This real-world data demonstrates that the results derived from men might not be applicable to women and it is critical to design studies with sufficient power to evaluate treatment effectiveness by sex.”

Dr. Lu-Yao and her colleagues aim to look into if the risk exists for women with other cancer types using more recent datasets. They also intend to collaborate on research to better understand how women’s immune systems differ from men’s.

Source: JAMA Network

Image Credit: Getty

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