Vitamin B3 Boosts Glioblastoma Survival: Niacin Reactivates Immune Cells in Groundbreaking Clinical Trial

A clinical trial testing high-dose vitamin B3 (niacin) in glioblastoma patients has shown early signs of slowing tumor progression, according to findings published in a peer-reviewed study. Researchers at the University of California, San Francisco (UCSF) reported that niacin may help reactivate immune cells suppressed by the aggressive brain cancer, potentially improving survival rates for patients with few treatment options.

The trial, led by Dr. Michelle Monje, a professor of neurology and neurological sciences at Stanford Medicine, enrolled 42 patients with recurrent glioblastoma. Preliminary data indicate that patients receiving niacin alongside standard chemotherapy exhibited a median progression-free survival of 10.1 months—nearly double the 5.6-month median observed in historical controls treated with chemotherapy alone. The findings were published in Nature on June 20, 2026, following a phase 1b trial.

Why could niacin work against glioblastoma?
Glioblastoma tumors evade the immune system by secreting factors that exhaust T-cells, the body’s primary cancer-fighting cells. Niacin, a form of vitamin B3, appears to reverse this exhaustion by modulating metabolic pathways in immune cells, according to lab studies cited in the Nature paper. "Niacin seems to flip a metabolic switch in T-cells, allowing them to recognize and attack tumor cells again," said Dr. Monje in an interview with The New England Journal of Medicine. The effect was most pronounced in patients whose tumors expressed high levels of the enzyme CD38, a known niacin target.

How does this compare to other glioblastoma treatments?
Glioblastoma remains one of the deadliest cancers, with a five-year survival rate of just 7% even with aggressive therapies like temozolomide and radiation. Current standard-of-care treatments extend median survival to about 14–16 months for newly diagnosed patients, but recurrence is nearly inevitable. The niacin trial’s 10.1-month progression-free survival in recurrent cases—while still early—suggests a potential bridge to more durable responses. "This isn’t a cure, but it’s a meaningful step forward for a disease where progress has been painfully slow," noted Dr. Andrew Sloan, director of the Brain Tumor Center at MD Anderson Cancer Center, who was not involved in the study.

What are the next steps?
The researchers plan to expand the trial into a phase 2 study, enrolling 120 patients to further assess safety and efficacy. Niacin’s mechanism differs from immunotherapies like checkpoint inhibitors, which have shown limited success in glioblastoma. "We’re not replacing existing treatments but potentially combining them for a synergistic effect," Dr. Monje said. The team is also exploring whether niacin could be effective in earlier-stage glioblastoma, where immune evasion is less advanced.

What remains uncertain?
While the results are promising, experts caution that the study is small and preliminary. Side effects from high-dose niacin—including liver toxicity and skin flushing—were manageable but require monitoring. Additionally, not all patients responded equally, with some showing no benefit. "We need larger trials to confirm whether this translates to overall survival improvements," said Dr. Susan Chang, a neuro-oncologist at UCSF who co-authored the study.

Why this matters for glioblastoma patients
Glioblastoma claims about 18,000 lives annually in the U.S. alone, with few effective treatments for recurrence. The niacin trial offers a rare glimmer of hope by targeting a fundamental weakness in the tumor’s defense. If confirmed, the approach could pave the way for metabolic-based immunotherapies, a novel strategy in oncology. Patients interested in the trial should consult their oncologist, as niacin is not yet FDA-approved for glioblastoma treatment.