Nivolumab and pembrolizumab as immune-modulating monoclonal antibodies targeting the PD-1 receptor to treat melanoma

Malignant melanoma is an important issue in oncology due to its high incidence, high mortality, and resistance to systemic therapy; however, targeted immunotherapy has noticeably improved the survival rates of melanoma patients. Promising targeted immunotherapies for malignant melanoma include the blockade of immune checkpoints with antibodies targeting cytotoxic T lymphocyte-associated antigen 4 and the programmed cell death protein 1 pathway. The US FDA-approved antibody ipilimumab targets cytotoxic T lymphocyte-associated antigen 4; however, it was limited by toxicity and a low response. Nivolumab and pembrolizumab (formerly lambrolizumab), the two FDA-approved anti-programmed death-1 monoclonal antibodies, show highly durable response rates and long-term safety, validating the importance of the programmed cell death protein 1 pathway blockade for treatment of malignant melanoma.

Spatial Regulation of T-Cell Signaling by Programmed Death-Ligand 1 on Wireframe DNA Origami Flat Sheets

Programmed Death-1 (PD-1) is a coinhibitory receptor expressed on activated T cells that suppresses T-cell signaling and effector functions. It has been previously shown that binding to its ligand PD-L1 induces a spatial reorganization of PD-1 receptors into microclusters on the cell membrane. However, the roles of the spatial organization of PD-L1 on PD-1 clustering and T-cell signaling have not been elucidated. Here, we used DNA origami flat sheets to display PD-L1 ligands at defined nanoscale distances and investigated their ability to inhibit T-cell activation in vitro. We found that DNA origami flat sheets modified with CD3 and CD28 activating antibodies (FS-α-CD3-CD28) induced robust T-cell activation. Co-treatment with flat sheets presenting PD-L1 ligands separated by ∼200 nm (FS-PD-L1-200), but not 13 nm (FS-PD-L1-13) or 40 nm (FS-PD-L1-40), caused an inhibition of T-cell signaling, which increased with increasing molar ratio of FS-PD-L1-200 to FS-α-CD3-CD28. Furthermore, FS-PD-L1-200 induced the formation of smaller PD-1 nanoclusters and caused a larger reduction in IL-2 expression compared to FS-PD-L1-13. Together, these findings suggest that the spatial organization of PD-L1 determines its ability to regulate T-cell signaling and may guide the development of future nanomedicine-based immunomodulatory therapies.

Peripheral blood immune cell-based biomarkers in anti-PD-1/PD-L1 therapy

Immune checkpoint blockade targeting PD-1 and PD-L1 has resulted in unprecedented clinical benefit for cancer patients. Anti-PD-1/PD-L1 therapy has become the standard treatment for diverse cancer types as monotherapy or in combination with other anti-cancer therapies, and its indications are expanding. However, many patients do not benefit from anti-PD-1/PD-L1 therapy due to primary and/or acquired resistance, which is a major obstacle to broadening the clinical applicability of anti-PD-1/PD-L1 therapy. In addition, hyperprogressive disease, an acceleration of tumor growth following anti-PD-1/PD-L1 therapy, has been proposed as a new response pattern associated with deleterious prognosis. Anti-PD-1/PD-L1 therapy can also cause a unique pattern of adverse events termed immune-related adverse events, sometimes leading to treatment discontinuation and fatal outcomes. Investigations have been carried out to predict and monitor treatment outcomes using peripheral blood as an alternative to tissue biopsy. This review summarizes recent studies utilizing peripheral blood immune cells to predict various outcomes in cancer patients treated with anti-PD-1/PD-L1 therapy.

Baseline neutrophil-to-lymphocyte ratio (NLR) is associated with clinical outcome in recurrent or metastatic head and neck cancer patients treated with nivolumab

Background: Nivolumab has been approved for recurrent or metastatic head and neck cancer (R/M HNC) on March 2017 in Japan. Recently, many researchers have been actively studying the prognostic and predictive markers. However, they have not been clarified. In this study, we evaluate the prognostic and predictive markers of the anticancer effect of nivolumab.Objective: This study assessed baseline neutrophil-to-lymphocyte ratio (NLR) as a prognostic and predictive marker for nivolumab efficacy in patients with recurrent/metastatic head and neck cancer (R/M HNC).Material and methods: This retrospective cohort study used medical records of patients with R/M HNC treated with nivolumab from May 2017 to January 2018 at a university hospital in Japan.Results: Twenty-nine patients (median age, 64 years) were included. In univariate analyses, baseline NLR ≥5 was significantly associated with overall survival (HR 4.88; p = .045) and progressive disease (HR 5.0; p = .046). More patients with baseline NLR ≥5 changed from nivolumab to best supportive care, compared to patients with baseline NLR <5 (64.3% vs 26.7%, respectively).Conclusions and significance: Baseline NLR was associated with clinical benefit from nivolumab in patients with R/M HNC. We propose that baseline NLR be used as a predictive or prognostic marker for nivolumab efficacy in these patients.

Programmed death-1 & its ligands: promising targets for cancer immunotherapy

Novel strategies for cancer treatment involving blockade of immune inhibitors have shown significant progress toward understanding the molecular mechanism of tumor immune evasion. The preclinical findings and clinical responses associated with programmed death-1 (PD-1) and PD-ligand pathway blockade seem promising, making these targets highly sought for cancer immunotherapy. In fact, the anti-PD-1 antibodies, pembrolizumab and nivolumab, were recently approved by the US FDA for the treatment of unresectable and metastatic melanoma resistant to anticytotoxic T-lymphocyte antigen-4 antibody (ipilimumab) and BRAF inhibitor. Here, we discuss strategies of combining PD-1/PD-ligand interaction inhibitors with other immune checkpoint modulators and standard-of-care therapy to break immune tolerance and induce a potent antitumor activity, which is currently a research area of key scientific pursuit.

Miller Fisher Syndrome Associated With Immunotherapy for Metastatic Melanoma

Immunotherapy is a treatment strategy that has demonstrated survival benefit for metastatic melanoma. Ipilimumab and nivolumab are examples of immunotherapy, in which monoclonal antibodies antagonize cytotoxic T-lymphocyte-associated protein 4 and programmed death-ligand 1 receptors, respectively, resulting in upregulation of the host immune response to cancer cells. There is increasing recognition of immune-mediated adverse events associated with immune therapies in patients with cancer. We present a case report of a patient who developed Miller Fisher syndrome associated with these therapies for metastatic melanoma along with a discussion of its management.

Molecular targeting of PD-1 signaling pathway as a novel therapeutic approach in HTLV-1 infection

HTLV-1, the first human oncogenic retrovirus, is a type C retrovirus that belongs to the Deltaretrovirus genus. The HTLV-1 genome has 8.5 kbp length, and consists of major genes such as gag, pol, pro, env, and pX region. This retrovirus is considered as one of the most deadly infectious agent for peripheral-blood mononuclear cells (PBMC). The infection of HTLV-1 can lead to dangerous complications, such as infective dermatitis (ID), uveitis, arthritis, lymphadenitis, arthropathies, Sjögren's Syndrome (SS), and particularly HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) or Adult T-Cell Leukemia Lymphoma (ATLL). At the moment, Zidovudine (AZT) plus IFN-α is the only treatment available for HTLV-1 infections. Based on scientific studies, alongside the therapeutic regimens, intrinsic mechanisms also play a determinant role in reducing the signs of disease. Programmed cell death-1 (PD-1) signaling pathway, one of the most important checkpoints, has recently received interest, such as the development of a novel generation of anti-tumors. In the present study, we discuss the role of PD-1 signaling pathway in HTLV-1 infection as well as its application as a novel approach for treatment of HTLV-1 infections.

C. tropicalis promotes CRC by down-regulating tumor cell-intrinsic PD-1 receptor via autophagy

Background: The programmed cell death 1 (PD-1) receptor is an immune checkpoint molecule that induces immune tolerance and mediates the immune escape of tumor cells. It is mainly expressed in immune cells such as T cells, B cells and monocytes. In recent years, studies have shown that tumor cell-intrinsic PD-1 plays different roles in the development of melanoma, Liver cancer and lung cancer. However, the expression and function of PD-1 in colon cancer cells has not been reported. Our previous studies have found that Candida tropicalis (C. tropicalis) can promote CRC tumor growth and chemotherapy resistance to oxaliplatin by regulating mismatch repair system. Whether C. tropicalis participates in the progression of CRC and immunotherapy resistance through regulating the tumor cell-intrinsic PD-1 remains to be further elucidated. Methods & Results: In this study, we first found that high concentrations of C. tropicalis promote tumor growth in cell cultures and xenografts. In addition, we proved that colon cancer cell lines express PD-1 receptors. Knockdown of PD-1 enhanced SW480 viability in-vitro, while overexpression of PD-1 diminished cell viability. Moreover, blocking antibody against PD-1 promotes tumor growth both in SW480 cells and mice CRC xenografts in an adaptive immune-independent manner. We also demonstrated that high concentrations of C. tropicalis can down-regulate tumor cell-intrinsic PD-1 expression in colon cancer cells. CRC cell growth induced by C. tropicalis is partially offset in the presence of PD-1 overexpression. This shows that C. tropicalis promotes CRC progression via controlling the expression of tumor cell-intrinsic PD-1. Mechanistically, we found that C. tropicalis modulates the expression of PD-1 via increasing the autophagy traffic in colon cancer cells. Combining autophagy inhibitor with C. tropicalis treatment partly blocked the CRC tumor growth and reversed the downregulation of PD-1. Conclusion: This study shows that PD-1 is a tumor suppressor in CRC. C. tropicalis can down-regulate tumor cell-intrinsic PD-1 expression via enhancing tumor cells autophagy levels to promote CRC progression. It may provide a new idea and mechanism for answering why the immune monoclonal antibody treatment is ineffective in cancer patients.

[Immunotherapeutic studies of head and neck tumors : Highlights of the 2016 ASCO Annual Meeting]

Immunotherapeutic drugs in the form of novel immune checkpoint inhibitors have had a significant impact on and revival of the treatment standards for head and neck tumors. Recently, at the annual meeting of the American Society of Clinical Oncology (ASCO) several innovative immunotherapies in head and neck cancer were presented, which might lead to a paradigm shift in the palliative as well as curative setting in the near future.The most common approaches are antibodies targeting the programmed cell death 1 (PD-1) axis. These therapies seem to be effective in a significant proportion of patients (independent of human papillomavirus) and show an extended duration of response.In a phase III trial for palliative second-line therapy, the PD-1 antibody nivolumab demonstrated a significant improvement in survival in patients with head and neck squamous cell carcinoma (HNSCC) who were experiencing disease progression after platinum-based therapy; therefore, the Food and Drug Administration gave it a breakthrough therapy designation.Further clinical trials focusing on first-line palliative treatment (compared with the EXTREME protocol) as well as neoadjuvant therapies using immune checkpoint-inhibitors are ongoing. However, valid testing systems (e. g., PD-L1 testing) as well as reliable predictive markers for patient selection are necessary to avoid increasing public health costs and to protect patients from potentially serious adverse events.

Pseudoprogression with Neoadjuvant Immunotherapy for Cutaneous Melanoma

Immune checkpoint inhibitors (ICI) have drastically changed the landscape of metastatic melanoma management, thus significantly improving survival. Clinically, assessing treatment response may be challenging in a portion of cases due to a massive influx of immune cells into the tumor microenvironment, causing a transient increase in the target lesion size. This phenomenon, coined pseudoprogression, can occur in 5-10% of metastatic patients, and it is commonly followed by a tumor regression. Its incidence, however, may be underestimated, given its ephemeral nature and often being documented in visceral metastatic lesions, which are only assessed by imaging scans every 2-3 months. More recently, ICI has been studied in the neoadjuvant setting, yielding durable pathological responses in patients with cutaneous melanoma. Here, we report a case of a large retroauricular melanoma mass with regional lymph node involvement treated with ipilimumab and nivolumab combination therapy that developed pseudoprogression. Initially documented as an increase in size along with inflammatory features, followed by a dramatic clinical improvement. A complete regression was pathologically documented after 3 months and the patient remains disease-free for 14 months after treatment initiation. In conclusion, we document a pseudoprogression case during neoadjuvant ICI treatment and raise the question of whether the incidence of this phenomenon is higher when observed in superficial lesions, which can be assessed by routine physical exam.

[Immunotherapy for HNSCC : Quo vadis?]

BACKGROUND

Immunotherapy remains a hot topic with an endless stream of new upcoming clinical trials. The results of studies to date are promising for second-line palliative treatment of head and neck squamous cell carcinoma (HNSCC). The next step is testing these strategies in randomized trials for first-line and curative treatment in an adjuvant, neoadjuvant, and primarily nonsurgical setting. So far, established biomarkers have not proven reliable enough to predict response rates precisely.

OBJECTIVES

On occasion of the annual meeting of the American Society of Clinical Oncology (ASCO), we aimed to invesitage the future of immunotherapies.

METHODS

We collected the most promising upcoming studies alongside current research in the field of biomarkers with a  view to interesting new immunotherapeutic strategies.

RESULTS

The search for appropriate biomarkers in particular seems to be a central research objective in the short term. There is a broad range of new agents that will be tested in clinical trials as well as the combination of immunotherapy with chemo- and chemoradiotherapy or other immune-modulating drugs.

CONCLUSION

The real challenge will be to find the most fitting therapy for each patient out of a large panel of available regimens. Therefore, it is most important to find a set of reliable biomarkers that together could predict treatment response.

Recombinant Expression and Purification of Extracellular Domain of the Programmed Cell Death Protein Receptor

BACKGROUND

The programmed cell death protein 1 (PD-1), which is a member of the CD28 receptor family, can negatively regulate antitumor immune responses by interacting with its ligands, PD-L1 or PD-L2. The PD-1-PD-L1 signaling pathway is a checkpoint mechanism that plays essential roles in downregulating immune responses in cancerous tissues. Thus, blocking this signaling pathway leads to enhanced antitumor immunity, potentially preventing tumor progression.

METHODS

We synthesized the extracellular domain of the PD-1 receptor (rPD-1) de novo by using a two-step polymerase chain reaction and the Phusion® DNA polymerase. The synthesized gene was cloned into the pET28 expression plasmid and transformed into competent Escherichia coli. Purification of rPD-1 was performed by metal-affinity chromatography, using a HisTrap column. Purified rPD-1 was characterized by western blotting and mass spectrometry using the SwissProt database and the Mascot program.

RESULTS

Designed and synthesized construct of rPD-1 was 500 bp in size. Analysis of the electrophoresis data of purified rPD-1 showed the presence of a protein with a molecular mass of 21 kDa. Mass spectrometry data using the SwissProt database and the Mascot program outputted the highest-scoring sequence to correspond to rPD-1.

CONCLUSION

Synthesized de novo rPD-1 may have potential therapeutic applications in enhancing antitumor immune responses.

The CD27/CD70 pathway negatively regulates visceral adipose tissue-resident Th2 cells and controls metabolic homeostasis

Adipose tissue homeostasis relies on the interplay between several regulatory lineages, such as type 2 innate lymphoid cells (ILC2s), T helper 2 (Th2) cells, regulatory T cells, eosinophils, and type 2 macrophages. Among them, ILC2s are numerically the dominant source of type 2 cytokines and are considered as major regulators of adiposity. Despite the overlap in immune effector molecules and sensitivity to alarmins (thymic stromal lymphopoietin and interleukin-33) between ILC2s and resident memory Th2 lymphocytes, the role of the adaptive axis of type 2 immunity remains unclear. We show that mice deficient in CD27, a member of the tumor necrosis factor receptor superfamily, are more resistant to obesity and associated disorders. A comparative analysis of the CD4 compartment of both strains revealed higher numbers of fat-resident memory Th2 cells in the adipose tissue of CD27 knockout mice, which correlated with decreased programmed cell death protein 1-induced apoptosis. Our data point to a non-redundant role for Th2 lymphocytes in obesogenic conditions.