Summary: Researchers at UCLA have identified a combination immunotherapy that markedly strengthens the immune response in patients with malignant gliomas. By pairing a personalized dendritic cell vaccine with the immune stimulant poly-ICLC, the treatment enhances dendritic cell function and T cell activity, showing promise against this aggressive brain tumor.
Malignant gliomas are aggressive, fast-growing brain tumors that infiltrate healthy tissue, making treatment difficult and prognosis often poor. This new approach—combining a patient-specific dendritic cell vaccine with a toll-like receptor (TLR) agonist—represents a promising strategy to improve immune recognition and anti-tumor activity, potentially shifting treatment paradigms and improving outcomes for people with these challenging cancers.
Key Facts:
- Enhanced immune activation: Adding poly-ICLC to a personalized dendritic cell vaccine significantly boosts interferon-driven immune responses and increases T cell activity against malignant gliomas.
- Personalized vaccine approach: The vaccine is made from a patient’s own white blood cells and tumor-derived protein antigens, training the immune system to recognize and attack tumor cells when reintroduced into the patient.
- Clinical potential: Early trial data link stronger interferon responses after treatment with longer survival and delayed progression, suggesting interferon activation may serve as a predictive blood biomarker for response to this combination immunotherapy.
Source: UCLA
Investigators at the UCLA Health Jonsson Comprehensive Cancer Center report that combining a personalized dendritic cell vaccine with the TLR agonist poly-ICLC amplifies anti-tumor immune responses in patients with malignant gliomas.
Published in Nature Communications, the randomized phase II study found that poly-ICLC, when given with an autologous tumor lysate-pulsed dendritic cell (ATL-DC) vaccine, produced a stronger systemic immune response than the vaccine alone or when paired with an alternate TLR agonist, resiquimod. The combination notably increased interferon-related gene expression and altered immune cell behavior consistent with heightened antitumor activity.
“Treating malignant gliomas is complex,” said Robert Prins, professor of molecular and medical pharmacology and neurosurgery at the David Geffen School of Medicine at UCLA and co-senior author of the study. “Because these tumors infiltrate brain tissue and are often located in critical areas, patients frequently face a poor prognosis. By increasing the potency of the vaccine with a TLR agonist, we aim to generate stronger anti-tumor immune responses.”
The ATL-DC vaccine, developed at UCLA, uses dendritic cells derived from a patient’s own blood. These dendritic cells are loaded with tumor protein antigens harvested from surgically removed tumor tissue. Once reintroduced to the patient, the dendritic cells train the immune system to detect and target tumor cells bearing those antigens.
Because the vaccine does not benefit all patients equally, the investigators tested whether adding TLR agonists could amplify immune activation. TLR agonists activate innate immune receptors on dendritic cells and macrophages, helping to prime and shape adaptive immune responses. The team compared poly-ICLC and resiquimod in combination with the ATL-DC vaccine to establish which adjuvant best improved immune potency and safety.
Twenty-three patients with WHO Grade III-IV gliomas, aged 26 to 72, were randomized to receive ATL-DC vaccination together with either poly-ICLC, resiquimod, or placebo. Researchers performed high-dimensional single-cell proteomic and transcriptomic analyses to track systemic immune changes induced by each TLR agonist. This detailed profiling revealed how treatment affected immune cell populations and signaling pathways across the body.
Poly-ICLC produced the most robust immune modulation: it amplified interferon-induced gene expression in monocytes and T lymphocytes, increased monocyte counts, elevated PD-1 expression on CD4+ T cells, and reduced CD38 and CD39 expression on CD8+ T cells—changes consistent with enhanced anti-tumor immunity. Importantly, higher interferon response signatures in peripheral blood correlated with longer survival and delayed progression in the trial cohort.
Although the survival association was statistically significant, the authors caution that the phase II trial was not powered to definitively establish clinical benefit for survival. Further, larger trials will be necessary to validate interferon activation as a reliable biomarker and to confirm the therapy’s impact on long-term outcomes.
“If confirmed in larger studies, measuring systemic interferon activation could help identify patients who are likely to benefit from combined poly-ICLC and dendritic cell vaccine therapy,” said Willy Hugo, assistant professor of medicine and co-first author. “Patients who show weak or absent interferon responses could be steered more quickly to alternative therapies or clinical trials, conserving valuable time in treating this aggressive disease.”
The researchers also suggest that combining ATL-DC plus poly-ICLC with immune checkpoint inhibitors may further enhance therapeutic benefit. A follow-up clinical trial testing this combination in patients with recurrent glioblastoma has already begun with support from the UCLA Specialized Program of Research Excellence (SPORE) in Brain Cancer.
“This research advances the development of more effective immunotherapies for gliomas and highlights the potential for a blood-based test to monitor vaccine-induced immune responses,” added Dr. Richard Everson, assistant professor of neurosurgery and co-first author.
The study’s co-senior authors include Dr. Linda Liau, professor and chair of neurosurgery. Additional contributors from UCLA include Lu Sun, Joseph Antonios, Alexander Lee, Lizhong Ding, Melissa Bu, Sarah Khattab, Carolina Chavez, Emma Billingslea-Yoon, Benjamin Ellingson, and Dr. Timothy Cloughesy. Prins, Hugo, Cloughesy, Ellingson, Everson, and Liau are all members of the UCLA Health Jonsson Comprehensive Cancer Center.
Funding: This study was supported in part by a grant from the National Cancer Institute.
About this brain cancer research news
Author: Denise Heady
Source: UCLA
Contact: Denise Heady – UCLA
Image: Image credited to Neuroscience News
Original Research: Open access. “TLR agonists polarize interferon responses in conjunction with dendritic cell vaccination in malignant glioma: a randomized phase II Trial” by Robert Prins et al., Nature Communications.
Abstract
TLR agonists polarize interferon responses in conjunction with dendritic cell vaccination in malignant glioma: a randomized phase II Trial
In this randomized phase II clinical trial, investigators evaluated the addition of TLR agonists—poly-ICLC or resiquimod—to autologous tumor lysate-pulsed dendritic cell (ATL-DC) vaccination in patients with newly diagnosed or recurrent WHO Grade III-IV malignant gliomas. Primary endpoints focused on identifying the most effective vaccine-adjuvant combination for enhancing immune potency and confirming safety.
The ATL-DC vaccine combined with a TLR agonist proved safe and promoted systemic immune activation, reflected by increased interferon gene expression and measurable changes in immune cell activation markers. Poly-ICLC specifically amplified interferon-induced genes in monocytes and T cells, increased monocyte counts, raised PD-1 expression on CD4+ T cells, and reduced CD38 and CD39 on CD8+ T cells. Patients with higher interferon-response gene expression experienced prolonged survival and slower disease progression, suggesting that interferon polarization in circulating immune cells could serve as a blood biomarker for immunotherapy response in this population.
Trial Registration: ClinicalTrials.gov Identifier: NCT01204684.