Researchers at Rockefeller University are reporting encouraging results from an early clinical trial of a redesigned cancer immunotherapy that not only shrank treated tumors but also affected tumors elsewhere in the body.

Findings published in the journal Cancer Cell showed that six of 12 patients experienced tumor shrinkage, while two patients achieved complete remission after receiving the experimental treatment.

The therapy is based on CD40 immunotherapy, a class of drugs designed to stimulate the immune system to recognize and attack cancer cells. Traditionally delivered through the bloodstream, these drugs can trigger significant side effects, including inflammation and liver damage.

To address those risks, researchers modified the drug, known as 2141-V11, and changed its delivery method. Instead of intravenous infusion, the therapy is injected directly into tumors, allowing for a more targeted immune response with reduced toxicity.

“We saw only mild toxicity,” said Jeffrey V. Ravetch, a study author at Rockefeller University.

In addition to shrinking injected tumors, the treatment appeared to trigger a systemic immune response, meaning tumors elsewhere in the body were also attacked by the immune system. This effect is considered rare in cancer treatment.

“This effect, where you inject locally but see a systemic response, is not something seen very often,” Ravetch said.

In some cases, tumors that were not directly treated also shrank or disappeared entirely. Researchers highlighted two patients with advanced cancers, one with melanoma and another with breast cancer, whose metastatic tumors were eliminated after injections were administered to a single site.

The therapy works by activating T cells, a type of immune cell capable of identifying and destroying cancer cells throughout the body once properly stimulated.

Despite the encouraging results, researchers cautioned that the trial was small and that further study is needed to confirm the findings. Larger clinical trials are already underway, with nearly 200 patients enrolled to evaluate the treatment’s safety and effectiveness.