Spanish Scientists Develop Drug Combination That Eliminates Pancreatic Tumors in Mice [1]

A study conducted by Spanish scientists has developed a drug combination therapy capable of completely eliminating pancreatic tumors in tests with mice. Beyond achieving total tumor regression, the strategy also prevented the development of treatment resistance—one of the major challenges in current oncology.

The research was published in the journal PNAS [4] in December 2025 and led by Mariano Barbacid, Director of the Experimental Oncology Group at Spain’s National Cancer Research Center (CNIO).

Results showed that tumors disappeared in different mouse models within three to four weeks.

Even after more than 200 days without treatment, the animals remained disease-free and showed no signs of therapy-related toxicity.

How it works: The therapy combines three compounds that act to halt tumor cell growth. One targets the KRAS oncogene, considered the main driver of pancreatic cancer. The other two act on the EGFR and STAT3 proteins, which are involved in signaling pathways essential for tumor progression.

About Pancreatic Cancer:

The pancreas is an organ located in the intra-abdominal region behind the stomach, between the small intestine and spleen. It is responsible for producing insulin and enzymes that help digest fats. Anatomically, it is divided into the head, body, and tail.

Pancreatic cancer tends to develop silently in its early stages. In more advanced phases, the tumor’s location may cause various symptoms. The most common type is adenocarcinoma, which accounts for over 90% of cases.

According to Brazil’s National Cancer Institute (Inca), due to its difficulty of detection and aggressive behavior, pancreatic cancer has a high mortality rate.

In Brazil—excluding non-melanoma skin cancers—the disease ranks 14th among the most frequent cancer types. It represents about 1% of all cancer diagnoses and is responsible for approximately 5% of cancer deaths nationwide.

In absolute numbers, Inca estimates that in 2020, the disease caused 5,882 deaths in men and 6,011 in women, making pancreatic cancer the 7th most lethal among men and the 5th among women.

Future Perspectives:

Despite promising laboratory results, the researchers emphasize that the next step involves refining the substances so they can be safely tested in human clinical trials.

The study is still in the experimental phase. However, the success of tumor regression without relying on the immune system suggests the therapy could be effective even in patients with compromised immunity.

The hope is that the findings will serve as a foundation for developing new clinical trials and may benefit pancreatic cancer patients in the future. The team acknowledges that adapting the therapy for human use "will not be easy," but believes the results open a new perspective for improving survival in a disease historically associated with limited treatment options