Tagged: immunotherapy

Immunotherapy Response in Primary vs Metastatic Pancreatic Cancer

In this editorial, researchers delve into the immunotherapeutic challenges posed by the tumor microenvironment and liver metastasis in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDA), a common type of pancreatic cancer, has proven to be largely resistant to immunotherapy, a treatment that uses the body’s immune system to fight cancer. Despite numerous successful pre-clinical trials using sophisticated PDA mouse models, clinical trials have failed to show a significant improvement in survival.

In a recent editorial, researchers Brian Diskin, Sarah Schwartz and George Miller from Trinity Health of New England shed light on the complex interplay between the immune system and pancreatic cancer. Their paper was published in Oncotarget on April 24, 2023, and entitled, “The critical immune basis for differential responses to immunotherapy in primary versus metastatic pancreatic cancer.”

Tumor Microenvironment and Liver Metastasis: Challenges in Pancreatic Cancer

The authors attribute PDA immunotherapy resistance to the unique characteristics of the tumor microenvironment (TME). The TME is often hypoxic and fibrotic, making it inaccessible to immune cells. Furthermore, the immune cells that do infiltrate the TME often have tolerogenic features, meaning they are more likely to tolerate the presence of cancer cells rather than attack them.

PDA most commonly metastasizes to the liver, an organ known for its immune tolerance. The liver is home to a diverse array of innate immune populations, including NK cells, Kupfer cells, NKT cells, and double negative T cells. Despite this, the liver is the most common location for metastasis from gastrointestinal cancers.

“It is an unfortunate fact that all failed clinical trials assessing immunotherapeutic efficacy were conducted in metastatic PDA, whereas basic preclinical investigations are usually performed in primary PDA using genetically engineered mouse models. We postulated that this dichotomy may explain the gap between preclinical promise and ultimate clinical failure.”

Divergent Responses to Immunotherapy: Primary vs. Metastatic 

“The potentially divergent responses to immunotherapy in the respective environments of primary versus metastatic PDA within the same host has not been well-studied.”

The authors highlight the lack of research into the potentially divergent responses to immunotherapy in primary versus metastatic PDA. They argue that this gap in knowledge may explain the discrepancy between the promising results of pre-clinical trials and the disappointing outcomes of clinical trials.

In their research, they discovered that the TMEs of primary PDA and liver metastases differ significantly, and this difference plays a critical role in the site-specific response to immunotherapy. They found that liver metastases are uniquely resistant to immunotherapies, in stark contrast to the immunotherapeutic responsiveness of primary PDA.

“We discovered that the respective TMEs of primary PDA and liver metastases differ markedly and this fact plays a critical role in dictating site-specific PDA response to immunotherapy [6].”

The Role of B Cells

The researchers identified B cells as a key player in this differential response. They found that B cells constituted approximately 25% of the tumor-infiltrating lymphocytes in metastatic PDA liver deposits, compared to approximately 10% in primary PDA. They also discovered a novel population of CD24+CD44–CD40– B cells in the metastatic liver, which is recruited to the metastatic milieu by Muc1hiIL18hi tumor cells.

“[…] by targeting B cells or blocking CD200/BTLA, we demonstrated enhanced macrophage and T-cell immunogenicity, which enabled immunotherapeutic efficacy of liver metastases.”

However, the authors note that primary PDA sites lack this b-cell population. Instead, they are characterized by macrophages and effector T cells that have a higher ability to provoke an immune response. This makes their immunotherapeutic responsiveness far more robust than metastatic liver PDA.


This research underscores the importance of understanding the immune basis of differential responses to immunotherapy in primary versus metastatic pancreatic cancer. It highlights the need for further research into the role of the TME and immune cells like B cells in the response to immunotherapy. Such insights could pave the way for more effective treatments for this challenging disease.

“[…] our data suggest that models of primary PDA are poor surrogates for evaluating immunity or treatment response in advanced disease.”

Click here to read the full editorial paper in Oncotarget.

Oncotarget is an open-access, peer-reviewed journal that has published primarily oncology-focused research papers since 2010. These papers are available to readers (at no cost and free of subscription barriers) in a continuous publishing format at Oncotarget.com. Oncotarget is indexed/archived on MEDLINE / PMC / PubMed.

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Epigenetics and Immunotherapy Combined Fights Rare Lymphoma

In a new Oncotarget study, researchers assessed an epigenetic and immunotherapy treatment regimen among patients with blastic mantle cell lymphoma (bMCL).

Mantle cell lymphoma
Mantle cell lymphoma
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Mantle cell lymphoma (MCL) is a type of non-Hodgkin’s lymphoma (NHL) that is aggressive, difficult to treat and typically affects older adults. Recurrence and mortality rates among patients with MCL have remained high, despite recent therapeutic advances. Blastic mantle cell lymphoma (bMCL) is a rare subtype of MCL associated with a worse disease trajectory.

“Despite recent advances, MCL is incurable except with allogeneic stem cell transplant. Blastic mantle cell lymphoma (bMCL) is a rarer subtype of cMCL associated with an aggressive clinical course and poor treatment response, frequent relapse and poor outcomes.”

In previous studies, researchers reported that a combination of epigenetic and immunotherapy treatments may have synergistic activity and offer better outcomes in patients with MCL. In the current study, Francis R. LeBlanc, Zainul S. Hasanali, August Stuart, Sara Shimko, Kamal Sharma, Violetta V. Leshchenko, Samir Parekh, Haiqing Fu, Ya Zhang, Melvenia M. Martin, Mark Kester, Todd Fox, Jiangang Liao, Thomas P. Loughran, Juanita Evans, Jeffrey J. Pu, Stephen E. Spurgeon, Mirit I. Aladjem, and Elliot M. Epner from Pennsylvania State University College of MedicinePenn State Hershey Cancer InstituteWinter Haven Hospital Cassidy Cancer CenterIcahn School of Medicine at Mount SinaiNational Cancer InstituteUniversity of VirginiaUVA Cancer CenterUniversity of Arizona College of MedicineOregon Health and Science University, and Beverly Hills Cancer Center used samples from a previous trial to perform correlative studies focused on clinical results in patients with blastic MCL. On August 16, 2022, their research paper was published in Volume 13 of Oncotarget, entitled, “Combined epigenetic and immunotherapy for blastic and classical mantle cell lymphoma.”

Epigenetic and Immunotherapy

Epigenetic therapy includes a range of drugs that can target epigenetic mechanisms, including DNA methylation and posttranslational modifications of histones. For example, vorinostat (SAHA; a histone deacetylase inhibitor) and cladribine (chemotherapy that also inhibits DNA methylation) are epigenetic agents. Rituximab, a maintenance immunotherapeutic agent, is a CD20-directed monoclonal antibody. These three treatments combined encompass a novel potential epigenetic and immunotherapy treatment regimen (SCR) for mantle cell lymphoma (MCL).

“Relapsed and [treatment] naïve MCL patients were treated with vorinostat (SAHA), cladribine and rituximab (SCR) regimen and followed for OS [overall survival], progression free survival (PFS) and with correlative basic science studies to investigate potential mechanisms of action of this epigenetic/immunotherapy combination.”

The Study

Since blastic MCL patients are rare, only 13 bMCL (four relapsed, nine previously untreated) patients treated with the SCR regimen were assessed in the prospective part of this study. All patients were male and Caucasian, and the median age at diagnosis was 62 years old. The patients were treated until they achieved remission, met the criteria for removal from the study, withdrew from the study, or passed away. Four patients were changed from rituximab to ofatumumab (a potent fully-human anti-CD20 antibody) due to rituximab intolerance (allergies, reactions) or lack of efficacy.

“Of 13 bMCL patients, all patients responded to therapy, with 12 patients meeting criteria for remission (CR, n = 6; PR, n = 6). Of those achieving CR, 5 remain in CR more than 5 years after diagnosis.”


After a median of 4.8 cycles of therapy, 12 patients achieved a complete response (CR), and one patient maintained stable disease (SD). The patients reported an increased overall survival greater than 40 months, and several patients maintained durable remissions without relapse for longer than five years. These results are remarkably superior to current treatment regimens with conventional chemotherapy, which range from 14.5-24 months among bMCL patients.

“The median OS of 43.4 months and PFS of 17.3 months for MCL patients with blastic disease treated with SCR therapy is one of the most important outcomes in this study.”

Another important finding was that the G/A870 CCND1 polymorphism was a strong predictor of blastic MCL, nuclear localization of cyclinD1 and response to SCR therapy. The team identified two distinct mechanisms of resistance to SCR therapy. The researchers reported that the loss of CD20 expression and evading treatment by seeking sanctuary in the central nervous system were two major resistance mechanisms to SCR therapy. 

“These data indicate that administration of epigenetic agents improves efficacy of anti-CD20 immunotherapies.”


Although the study sample was relatively small, the researchers’ results are promising. The SCR regimen was demonstrated to be an effective epigenetic and immunotherapy treatment for mantle cell lymphoma, with long-term remissions and improved overall survival in bMCL patients. Researchers revealed important insights into the mechanisms of action of SCR and potential resistance mechanisms. This study also highlights the potential for future research exploring the efficacy of SCR in other cancers, along with other predictive biomarkers of response.

“This approach is promising in the treatment of MCL and potentially other previously treatment refractory cancers.”

Click here to read the full research paper published by Oncotarget

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Oncotarget is an open-access journal that publishes primarily oncology-focused research papers in a continuous publishing format. These papers are available at no cost to readers on Oncotarget.com. Open-access journals have the power to benefit humanity from the inside out by rapidly disseminating information that may be freely shared with researchers, colleagues, family, and friends around the world.

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