Lung cancer treatment for dogs may also work on humans with deadly tumors

SACRAMENTO— Dogs once again show that they deserve the title of man’s best friend. With the help of dogs, researchers at the University of California-Davis Health have found a specific protein in the body that could create more effective immunotherapies. The protein would help trigger the immune system to better respond and eliminate the cancer.

The clinical study involved 21 pet dogs who developed metastatic lung disease due to bone or skin cancer. The team treated dogs with the cytokine interleukin-15 (IL-15), which scientists believe is beneficial for immunotherapy. However, IL-15 treatments in humans are rare because certain doses carry high risks of toxicity.

“Nobody had ever given IL-15 as an inhaled treatment to dogs before to deliver it directly to the cancer site. We came up with this idea as a way to reduce exposure to the rest of the body, in order to improve the benefit-risk ratio, improve immunostimulatory effects and reduce toxicity,” says Robert J. Canter, a canine oncologist and chief of the UC Davis Division of Surgical Oncology, in an academic statement.

“In this study, we used interleukin-15 to invigorate the immune system to recognize cancer cells that had evaded the immune system and eliminate them.”

Inhalation of IL-15 reduced cancerous tumors

The dogs inhaled a mist of IL-15 twice a day. The dosage increased over time to improve efficacy and allow researchers to determine a safe dose. Within 14 days of inhaling the mist, the dogs’ health began to improve.

Doctors have found that giving large amounts of IL-15 helps boost the immune system’s defenses against several cancers in dogs. The overall response rate was close to 40%. Two dogs’ tumors have shrunk significantly and one went into remission for over a year.

“The inhaled IL-15 responses we observed in dogs are better than in previous human studies, but clinical benefit is seen in less than half of the dogs. Use of IL-15 in humans led to potentially favorable immune responses, but did not yield good tumor responses. This indicates that combining IL-15 with other immunotherapies may result in additive or synergistic responses,” says Robert B. Rebhun, canine oncologist at UC Davis School of Veterinary Medicine and associate director of the control program. cancer at the Center for Companion Animal Health. .

Treatment works best with other medications

The two main findings of the study were that dogs tolerated IL-15 therapy well and that within two weeks it helped suppress metastatic cancer. However, researchers warn that IL-15 alone is not enough to eliminate cancer completely. Rather, they recommend that it works best in combination with other cancer treatments.

“All of the canine patients in this study had advanced metastatic cancer, and the majority had previously received chemotherapy, radiation therapy and, in some cases, immunotherapy. Studies are currently underway to see if we can predict which patients might respond. to this therapy depending on the properties of the tumor or the immune status of the patient,” explains Dr. Rebhun.

The findings could also provide insight into the response of IL-15 treatment in humans and potentially speed the process of getting IL-15 therapy as an adjunct option to chemo or to immunotherapy.

The study is published in the Journal for Cancer Immunotherapy.

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