Study ignores possibility that drugs, chemicals affect sexes differently

Many of the medicines we take were only ever tested on men during clinical studies. This poses a distinct danger that females are receiving suboptimal care—and that treatments specifically benefiting women are going undiscovered. As a recent U.S. Government Accountability Office study reported, 80 percent of the drugs withdrawn from the market are removed due to side effects on women. For example, in 2013—20 years after the drug first became available—the recommended dosage of a popular sedative for women was cut in half after it was realized that women process the drug more slowly than men and were experiencing serious side effects as a result. Indeed, as noted in The Guardian, the science that informs modern medicine—including the prevention, diagnosis and treatment of disease—routinely fails to consider the crucial impact of sex and gender. This lapse ignores the possibility that diseases, treatments and chemicals affect the sexes differently.

Even as the Office of Research on Women's Health—a division of the National Institutes of Health—includes as part of its mandate a focus on engaging, recruiting and retaining women when planning, designing and conducting clinical research, there is still work to do. In an effort to reduce the gender bias that is leaving women exposed to critical health risks, the Research for All Act—which would require federally funded research to perform studies on both male and female animals, cells and tissue—was first introduced into Congress in 2014 and reintroduced in 2015.

Brad Thompson, Ph.D., the president and CEO of Oncolytics Biotech Inc., has observed firsthand how improved, targeted treatments for women may result from their participation in clinical studies. Oncolytics recently reported preliminary data from a Phase II study of its lead product, REOLYSIN®, a proprietary formulation of the human reovirus, in advanced or metastatic colorectal cancer, in combination with other cancer drugs. In the study, female patients had an objective response rate of 63.2 percent versus 23.8 percent in the control arm—a result with a level of significance higher than that observed among the men in the study. The company intends to follow-up this study with an additional study in female metastatic colorectal patients. In a separate Phase II study of REOLYSIN® and other cancer drugs in patients with non-small cell lung cancer, once again, female patients did better than in the standard treatment arms than male patients.

There is growing recognition of the importance of developing immunotherapies (like REOLYSIN®) to specifically treat women. Earlier this year, for example, the journal Oncology published a feature spotlighting new strategies for the treatment of gynecological malignancies using immunotherapy. The Oncolytics study results, however, indicate that specific therapies for women might arise in cancers that impact both sexes.

Following the release of preliminary data from the colorectal cancer study, Dr. Thompson expressed encouragement that the inclusion of REOLYSIN® in the treatment combination may have "a profound impact" on response rates for women with colorectal cancer. Various immune-based therapies, he noted, have demonstrated a profile where patients derive tumor response and overall survival benefit with limited or no impact on progression free survival; according to Dr. Thompson, REOLYSIN®, as an oncolytic virotherapy, appears to be demonstrating a similar profile in female patients with advanced or metastatic colorectal cancer. Similarly, regarding the preliminary data from the non-small cell lung cancer study, Dr. Thompson expressed encouragement to see a gender linkage to progression free survival and overall survival.

The recent study results announced by Oncolytics lend weight to a crucial possibility: there could exist important treatments for women that are within researchers' grasp. This raises the question: have other researchers overlooked gender-specific data because the overall data were not sufficient to move forward in the clinical development process? Are there other therapies that may have potential if administered in a more personalized approach?

Addressing the imbalance in the male-to-female ratio within studies could help ensure that women-specific treatments—capable of helping the female half of the patient population—may eventually become reality.