OU Medicine Cancer Researchers Help Uncover Why Obese Patients Have Better Response to Immunotherapy

Obesity has long been associated with encouraging the growth of tumor cells, but a recent study reveals that obesity can also play a role in improved outcomes in cancer patients treated with immunotherapy. Physician-scientists from the Stephenson Cancer Center at OU Medicine participated in this collaborative study along with researchers from the UC Davis Cancer Center in Sacramento.

The seemingly-contradictory findings were recently published in the November issue of Nature Medicine, a high-impact monthly journal that showcases innovative and novel research.

At the Stephenson Cancer Center, Sami Ibrahimi, M.D., and Raid Aljumaily, M.D., both hematologist-oncologists, looked at the outcomes of cancer patients who received anti-PD-1 and PDL-1 therapy, a type of immunotherapy. Immunotherapy is a cancer treatment that uses the body’s immune system to fight cancer.

They found that obese patients with a body mass index of more than 30 had increased time living without cancer progression and better survival rates in general compared to patients with a BMI of less than 30. These results were also consistent with findings from studies done at the UC Davis Cancer Center with other experimental models.

“While obesity is a major risk factor for multiple types of cancers, the immune system in obese patients can be more responsive to reactivation by immunotherapy to fight cancer cells” said Ibrahimi.

Data found that obese patients experienced a higher exhaustion rate among T cells in the body, and in return they expressed greater dysfunction and higher amounts of PD-1 and PD-L1. Overall, this made the tumors more responsive to treatment.

“What we learn from this study will help make immunotherapy more effective in more patients, regardless of their body mass index,” said Aljumaily. “Our goal with the next phase of this study is to investigate other cancer resistance mechanisms and identify additional targets to improve the effectiveness of immunotherapy in more patients.”

Additional researchers from the University of Oklahoma Health Sciences Center who participated with this study include Michael Machiorlatti, MS, graduate research assistant, and Sara K. Vesely, PhD, MPH, professor of biostatistics and epidemiology.

Immunotherapy research at Stephenson Cancer Center is conducted primarily through the Oklahoma TSET Phase I Center, offering Oklahoma’s only early-phase clinical trial program in the state, providing patients access to cutting-edge cancer treatments.

The article, “Paradoxical effects of obesity on T cell function during tumor progression and PD-1 checkpoint blockage,” was published in the November issue of Nature Medicine. Nature Medicine is a monthly, peer-reviewed publication dedicated to high-impact biomedical research.