Blood Pressure Drug Shows Promise Against Childhood Cancer

A treatment that started with lab research and moved to dogs is now giving new hope to children battling one of the deadliest bone cancers.

Researchers at Colorado State University have successfully treated nine pediatric osteosarcoma patients using losartan, a common blood pressure drug, combined with an oral chemotherapy medication. All nine patients tolerated the treatment well, and blood tests show their immune systems responding exactly as doctors hoped.

Osteosarcoma strikes about 1,000 children and teens each year in the United States. It spreads quickly to the lungs, often requires limb amputation, and hasn't seen new treatment options in 40 years. Kids who relapse have almost nowhere to turn.

Dr. Dan Regan and his team at CSU's Flint Animal Cancer Center discovered something remarkable more than a decade ago. Losartan could disrupt harmful immune cells called monocytes that help cancer spread through the body. They tested the drug combination on dogs with osteosarcoma first, since dogs develop this cancer at much higher rates than humans.

The results in dogs were encouraging. Half of the treated dogs saw their lung tumors shrink significantly or stop growing for at least eight weeks, sometimes for more than six months.

That success opened the door for human trials starting in 2019. The current phase 1 trial at children's hospitals in Aurora, Atlanta, and Los Angeles focuses on finding safe dosage levels. Nine patients have now received treatment at three progressively higher doses.

The latest blood samples reveal something exciting. Patients are reaching the same losartan levels that successfully treated dogs. Their harmful monocytes are decreasing while helpful immune cells are increasing.

Dr. Kelly Faulk, a pediatric oncologist at Children's Hospital Colorado, calls the progress extremely promising. The team is currently enrolling patients at the third of four planned dosage levels.

The Ripple Effect

This research shows how studying cancer in pets can accelerate breakthroughs for children. Dogs naturally develop osteosarcoma at rates 27 times higher than humans, making them ideal partners in finding treatments. Every advancement helps both species.

The path from laboratory bench to dog patients to human trials took over a decade of careful work. Researchers chose losartan specifically because it was already FDA-approved, meaning they understood its safety profile and could potentially repurpose it quickly.

Now children with few options have access to a treatment that's not only safer than traditional toxic chemotherapy regimens but appears to boost their own immune systems to fight cancer. The trial continues recruiting patients to find the optimal dose that maximizes benefits while maintaining safety.

For families facing a disease with outcomes unchanged in four decades, this represents genuine progress toward better treatments.