Vitamin D analog paricalcitol shows promise against pancreatic cancer in early trial

October 3, 2026 at 05:00 AM2 min

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A small clinical trial led by Dana Farber Cancer Institute found that adding the vitamin D analog paricalcitol to standard chemotherapy was safe for patients with untreated metastatic pancreatic cancer. The combination also reduced fibroblast activation in the tumor microenvironment, supporting earlier Salk Institute laboratory findings. The trial was not designed to measure survival, but patients receiving paricalcitol had more responses and longer progression-free survival at one year.

Key Facts

The study, published in Nature Cancer, included patients with previously untreated metastatic pancreatic cancer.
Paricalcitol is a vitamin D analog already approved by the FDA for other medical uses.
Patients who received paricalcitol with chemotherapy had more responses to treatment and were more likely to remain free of disease progression after one year.
Those whose tumors had high levels of the vitamin D receptor and who received paricalcitol had the longest overall survival.
About 13% of all FDA approved drugs currently work by targeting nuclear receptors.

Trial Design and Safety

The trial was led by researchers at Dana Farber Cancer Institute and built on laboratory discoveries at the Salk Institute. Participants received standard chemotherapy either alone or in combination with paricalcitol, a vitamin D analog already approved by the FDA for other medical uses. Whether paricalcitol was given by mouth or intravenously, researchers found that it could be combined safely with chemotherapy overall. The drug also reduced the activation of fibroblasts in the tumor microenvironment, providing evidence in patients that supported earlier findings from Salk laboratory studies.

Clinical Signals and Survival

Although the trial was not designed to determine whether the treatment improved pancreatic cancer outcomes, researchers observed encouraging signals. Patients who received paricalcitol with chemotherapy had more responses to treatment and were more likely to remain free of disease progression after one year. Those whose tumors had high levels of the vitamin D receptor and who received paricalcitol also had the longest overall survival. Study co-author Ronald Evans, PhD, professor and the March of Dimes Chair in Molecular and Developmental Biology at Salk, said the study takes a novel approach for cracking therapeutic resistance in pancreatic cancer.

Vitamin D Receptor Biology

Evans discovered the nuclear receptor superfamily, a major class of molecules that includes the vitamin D receptor. Nuclear receptors respond to substances such as hormones, vitamins, and lipids, then influence cell behavior by switching genes on and off. About 13% of all FDA approved drugs currently work by targeting nuclear receptors. Earlier research by Evans and his colleagues showed that the vitamin D receptor helps regulate fibroblasts in the liver and pancreas in preclinical models. The Salk researchers further showed that synthetic forms of vitamin D, including paricalcitol, could block liver fibrosis and pancreatitis in experimental models.