Vitamin D drug may help crack pancreatic cancer’s protective shield — SkimNews
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- Paricalcitol plus chemotherapy produced a 42% partial response rate (10 of 24 patients) versus 9% (1 of 12) on placebo in a 36-patient randomized trial of previously untreated metastatic pancreatic cancer, published in Nature Cancer on October 3, 2026.
- Ronald Evans, PhD at the Salk Institute discovered the vitamin D receptor's role in regulating fibroblasts and showed in preclinical models that synthetic vitamin D could reverse cancer-associated fibroblast activation in pancreatic tumors — the foundational work behind the trial.
- Brian Wolpin, MD, MPH and Kimberly Perez, MD at Dana Farber Cancer Institute led the randomized, multiarm trial, in which patients received gemcitabine plus nab-paclitaxel with either placebo, IV paricalcitol, or oral paricalcitol, and underwent tumor biopsies before and after 4–6 weeks of treatment.
- Paired tumor biopsies analyzed by multiplex immunofluorescence and spatial transcriptomics showed paricalcitol reduced fibroblast activation and increased T cell infiltration — patient-level evidence that the drug remodels the tumor microenvironment rather than directly killing cancer cells.
- Five of 12 patients on oral paricalcitol developed elevated blood calcium (hypercalcemia), a known class effect, which researchers managed with standard dose reductions; the combination was otherwise safely administered.
- Patients with high tumor vitamin D receptor levels who received paricalcitol had the strongest chemotherapy responses and the longest overall survival, suggesting VDR expression could serve as a predictive biomarker for selecting candidates.
- Paricalcitol is already FDA-approved to treat secondary hyperparathyroidism in chronic kidney disease, putting the drug on a potential fast track to be repurposed for pancreatic cancer if larger confirmatory trials succeed.
Why it matters: Pancreatic cancer resists chemotherapy largely because a dense fibrotic shield limits drug penetration and immune access. This trial is the first randomized study to show in patients that a drug can dismantle that shield and measurably improve chemo response, while flagging vitamin D receptor levels as a candidate biomarker to enrich for responders in the larger trials the authors say are now needed.
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