Survival, durable tumor remission, and long-term safety in patients with advanced melanoma receiving nivolumab

Risk of Immune-Related Pneumonitis with PD-1/PD-L1 Inhibitors in Different Cancer Types and Treatment Regimens: A Systematic Review and Meta-Analysis of 22 Randomized Controlled Trials

BACKGROUND

Pneumonitis, the specific toxicity associated with PD-1/PD-L1 inhibitors, is severe and potentially life-threatening, and its incidence and severity are poorly understood among different tumor types or treatment methods. This meta-analysis was performed to compare the incidence and severity of pneumonitis among different tumor types and treatment regimens.

METHODS

MEDLINE and Embase were retrieved until September 2021. Meta-analysis of the risk of pneumonitis was calculated using a fixed-effect model. Pooled analysis of the incidence of pneumonitis in different tumor types was performed using a metaprop function.

RESULTS

Twenty two randomized controlled trials (RCTs) (n = 10,700) were included for pool analysis, and eighteen RCTs (n = 8,852) were eligible for meta-analysis. For all-grade pneumonitis, the risk of the combination therapy (PD-1/PD-L1 plus CTLA-4 inhibitor) was 3.62 times significantly higher than that of monotherapy, and 4.06 and 1.78 times significantly higher than that of chemotherapy and placebo than monotherapy. The incidence of pneumonitis was not significantly different between PD-1/PD-L1 inhibitor versus ipilimumab or between low doses versus high doses. For high-grade (grade ≥3) pneumonitis, the risk in PD-1/PD-L1 inhibitors alone was 3.62 times significantly higher than chemotherapy. No significant difference was found in the incidence of pneumonitis between combination versus monotherapy, monotherapy versus placebo, combination versus ipilimumab alone, monotherapy versus ipilimumab alone, or low doses versus high doses.

CONCLUSIONS

Compared with chemotherapy, PD-1/PD-L1 inhibitor monotherapy may cause more treatment-related pneumonitis. Increasing the dose of PD-1/PD-L1 inhibitor does not significantly increase the incidence of pneumonitis. Compared with the monotherapy, combination therapy does not increase the incidence of pneumonitis significantly.

Checkpoint Inhibitors and Induction of Celiac Disease-like Condition

Immune checkpoint inhibitors herald a new era in oncological therapy-resistant cancer, thus bringing hope for better outcomes and quality of life for patients. However, as with other medications, they are not without serious side effects over time. Despite this, their advantages outweigh their disadvantages. Understanding the adverse effects will help therapists locate, apprehend, treat, and perhaps diminish them. The major ones are termed immune-related adverse events (irAEs), representing their auto-immunogenic capacity. This narrative review concentrates on the immune checkpoint inhibitors induced celiac disease (CD), highlighting the importance of the costimulatory inhibitors in CD evolvement and suggesting several mechanisms for CD induction. Unraveling those cross-talks and pathways might reveal some new therapeutic strategies.

Remodeling tumor immunosuppressive microenvironment via a novel bioactive nanovaccines potentiates the efficacy of cancer immunotherapy

The clinical outcomes of cancer nanovaccine have been largely impeded owing to the low antigen-specific T cell response rate and acquired resistance caused by the immunosuppressive tumor microenvironment (TME). Here, we reported a tumor acidity-responsive nanovaccine to remodel the immunosuppressive TME and expand the recruitment of tumor infiltrating lymphocytes (TILs) using hybrid micelles (HM), which encapsulated colony stimulating factor 1 receptor (CSF1-R) inhibitor BLZ-945 and indoleamine 2,3-dioxygenase (IDO) inhibitor NLG-919 in its core and displayed a model antigen ovalbumin (OVA) on its surface (denoted as BN@HM-OVA). The bioactive nanovaccine is coated with a polyethylene glycol (PEG) shell for extending nanoparticle circulation. The shell can be shed in response to the weakly acidic tumor microenvironment. The decrease in size and the increase in positive charge may cause the deep tumor penetration of drugs. We demonstrated that the bioactive nanovaccine dramatically enhance antigen presentation by dendritic cells (DCs) and drugs transportation into M1-like tumor-associated macrophages (TAMs) and tumor cells via size reduction and increasing positive charge caused by the weakly acidic TME. Such bioactive nanovaccine could remodel the immunosuppressive TME into an effector T cells favorable environment, leading to tumor growth inhibition in prophylactic and therapeutic E.G7-OVA tumor models. Furthermore, combining the bioactive nanovaccine with simultaneous anti-PD-1 antibody treatment leads to a long-term tumor inhibition, based on the optimal timing and sequence of PD-1 blockade against T cell receptor. This research provides a new strategy for the development of efficient cancer immunotherapy.

•

A bioactive nanovaccine (BN@HM-OVA) was adopted for synergistic immunotherapy of E.G7-OVA tumors.

•

BN@HM-OVA exhibited superior ability to induce DCs maturation and robust antigen-specific T cell responses.

•

BN@HM-OVA contributed to a homeostasis in the tumor microenvironment ideal for antitumor vaccination.

•

The combination treatment of BN@HM-OVA and αPD-1 achieved maximum therapeutic benefits.

Melanoma: An update on systemic therapies

Despite advances in early detection as described in part 1 of this continuing medical education series, melanoma continues to be a large contributor to cutaneous cancer-related mortality. In a subset of patients with unresectable or metastatic disease, surgical clearance is often not possible; therefore, systemic and local therapies are considered. The second article in this series provides dermatologists with an up-to-date working knowledge of the treatment options that may be prescribed by oncologists for patients with unresectable stage III, stage IV, and recurrent melanoma.

Re-administration of nivolumab after immune checkpoint inhibitor-induced cholangitis: the first reported case

Immune checkpoint inhibitors (ICIs) cause various immune-related adverse events (irAEs). We encountered a patient in whom nivolumab was re-administered effectively and safely treat laryngeal cancer after nivolumab-induced cholangitis. A 60-year-old man with metastatic laryngeal squamous cell carcinoma received 3rd-line treatment with nivolumab. After the 8th cycle of chemotherapy, laboratory tests revealed grade 3 elevations of gamma-glutamyl transpeptidase and alkaline phosphatase. Computed tomography and endoscopic retrograde cholangiopancreatography showed diffuse hypertrophy, dilation of bile ducts, and intrahepatic bile ducts with irregular walls and mild stenosis. The histologic findings of a liver biopsy revealed portal inflammation and cholangitis, mainly composed of T cell infiltration. We diagnosed nivolumab-induced cholangitis and administered 30 mg of prednisolone (0.5 mg/kg) and ursodeoxycholic acid (600 mg) per day. Although we initiated 4th-line cytotoxic anticancer drug after the cholangitis improved, the laryngeal cancer progressed rapidly. Based on the improvement in hematologic parameters, radiologic imaging, and pathologic findings, we cautiously restarted nivolumab. During the 30 months after re-administration of nivolumab, the cholangitis did not recur and the disease was well-controlled.

Controlling Cell Trafficking: Addressing Failures in CAR T and NK Cell Therapy of Solid Tumours

The precision guiding of endogenous or adoptively transferred lymphocytes to the solid tumour mass is obligatory for optimal anti-tumour effects and will improve patient safety. The recognition and elimination of the tumour is best achieved when anti-tumour lymphocytes are proximal to the malignant cells. For example, the regional secretion of soluble factors, cytotoxic granules, and cell-surface molecule interactions are required for the death of tumour cells and the suppression of neovasculature formation, tumour-associated suppressor, or stromal cells. The resistance of individual tumour cell clones to cellular therapy and the hostile environment of the solid tumours is a major challenge to adoptive cell therapy. We review the strategies that could be useful to overcoming insufficient immune cell migration to the tumour cell mass. We argue that existing 'competitive' approaches should now be revisited as complementary approaches to improve CAR T and NK cell therapy.

Cancer immunotherapy by immune checkpoint blockade and its advanced application using bio-nanomaterials

Cancer is the second leading cause of death worldwide. Traditional approaches, such as surgery, chemotherapy, and radiotherapy have been the main cancer therapeutic modalities in recent years. Cancer immunotherapy is a novel therapeutic modality that potentiates the immune responses of patients against malignancy. Immune checkpoint proteins expressed on T cells or tumor cells serve as a target for inhibiting T cell overactivation, maintaining the balance between self-reactivity and autoimmunity. Tumors essentially hijack the immune checkpoint pathway in order to survive and spread. Immune checkpoint inhibitors (ICIs) are being developed as a result to reactivate the anti-tumor immune response. Recent advances in nanotechnology have contributed to the development of successful, safe, and efficient anticancer drug systems based on nanoparticles. Nanoparticle-based cancer immunotherapy overcomes numerous challenges and offers novel strategies for improving conventional immunotherapies. The fundamental and physiochemical properties of nanoparticles depend on various cancer therapeutic strategies, such as chemotherapeutics, nucleic acid-based treatments, photothermal therapy, and photodynamic agents. The review discusses the use of nanoparticles as carriers for delivering immune checkpoint inhibitors and their efficacy in cancer combination therapy.

The Effect of Albumin-Binding Moiety on Tumor Targeting and Biodistribution Properties of 67Ga-Labeled Albumin Binder-Conjugated Alpha-Melanocyte-Stimulating Hormone Peptides

Background: The purpose of this study was to examine the effect of 4-p-(tolyl)butyric acid as an albumin-binding (ALB) moiety on tumor targeting and biodistribution properties of ⁶⁷Ga-labeled albumin binder-conjugated alpha-melanocyte-stimulating hormone peptides. Materials and Methods: DOTA-Lys(ALB)-G/GG/GGG-Nle-CycMSH_hex {1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-Lys(ALB)-Gly/GlyGly/GlyGlyGly-Nle-c[Asp-His-DPhe-Arg-Trp-Lys]-CONH₂} were synthesized with 4-p-(tolyl)butyric acid serving as an ALB moiety. The melanocortin-1 receptor (MC1R)-binding affinities of the peptides were determined on B16/F10 melanoma cells. The biodistribution of ⁶⁷Ga-DOTA-Lys(ALB)-G/GG/GGG-Nle-CycMSH_hex was examined on B16/F10 melanoma-bearing C57 mice at 2 h postinjection to select a lead peptide for further evaluation. The melanoma targeting and imaging properties of ⁶⁷Ga-DOTA-Lys(ALB)-GGNle-CycMSH_hex {⁶⁷Ga-ALB-G2} were determined on B16/F10 melanoma-bearing C57 mice. Results: The IC₅₀ value of DOTA-Lys(ALB)-G/GG/GGG-Nle-CycMSH_hex {ALB-G1, ALB-G2, ALB-G3} was 0.67 ± 0.07, 0.5 ± 0.09 and 0.51 ± 0.03 nM on B16/F10 cells, respectively. ⁶⁷Ga-ALB-G2 was further evaluated as a lead peptide because of its higher tumor uptake (30.25 ± 3.24%ID/g) and lower kidney uptake (7.09 ± 2.22%ID/g) than ⁶⁷Ga-ALB-G1 and ⁶⁷Ga-ALB-G3 at 2 h postinjection. The B16/F10 melanoma uptake of ⁶⁷Ga-ALB-G2 was 15.64 ± 4.55, 30.25 ± 3.24, 26.76 ± 3.23, and 10.71 ± 1.21%ID/g at 0.5, 2, 4, and 24 h postinjection, respectively. The B16/F10 melanoma lesions were clearly visualized by SPECT/CT using ⁶⁷Ga-ALB-G2 as an imaging probe at 2 h postinjection. Conclusions: The introduction of 4-p-(tolyl)butyric acid as an ALB moiety increased the blood retention, and resulted in higher tumor/kidney ratio of ⁶⁷Ga-ALB-G2 as compared with its counterpart without an albumin binder. However, the resulting high uptake of ⁶⁷Ga-ALB-G2 in blood and liver need to be further reduced to facilitate its therapeutic application when replacing ⁶⁷Ga with therapeutic radionuclides.

Volume of Disease as a Predictor for Clinical Outcomes in Patients With Melanoma Brain Metastases Treated With Stereotactic Radiosurgery and Immune Checkpoint Therapy

Purpose/Objectives

Clinical trials of anti-Programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein (CTLA-4) therapies have demonstrated a clinical benefit with low rates of neurologic adverse events in patients with melanoma brain metastases (MBMs). While the combined effect of these immunotherapies (ITs) and stereotactic radiosurgery (SRS) has yielded impressive results with regard to local control (LC) and overall survival (OS), it has also been associated with increased rates of radiation necrosis (RN) compared to historical series of SRS alone. We retrospectively reviewed patients treated with IT in combination with SRS to report on predictors of clinical outcomes.

Materials and Methods

Patients were included if they had MBMs treated with SRS within 1 year of receiving anti-PD-1 and/or CTLA-4 therapy. Clinical outcomes including OS, LC, intracranial death (ID), and RN were correlated with type and timing of IT with SRS, radiation dose, total volume, and size and number of lesions treated.

Results

Twenty-nine patients with 171 MBMs were treated between May 2012 and May 2018. Patients had a median of 5 lesions treated (median volume of 6.5 cm³) over a median of 2 courses of SRS. The median dose was 21 Gy. Most patients were treated with ipilimumab (n = 13) or nivolumab-ipilimumab (n = 10). Most patients underwent SRS concurrently or within 3 months of receiving immunotherapy (n = 21). Two-year OS and LC were 54.4% and 85.5%, respectively. In addition, 14% of patients developed RN; however, only 4.7% of the total treated lesions developed RN. The median time to development of RN was 9.5 months. Patients with an aggregate tumor volume >6.5 cm³ were found to be at increased risk of ID (p = 0.05) and RN (p = 0.03). There was no difference in OS, ID, or RN with regard to type of IT, timing of SRS and IT, number of SRS courses, SRS dose, or number of cumulative lesions treated.

Conclusions

In our series, patients treated with SRS and IT for MBMs had excellent rates of OS and LC; however, patients with an aggregate tumor volume >6.5 cm³ were found to be at increased risk of ID and RN. Given the efficacy of combined anti-PD-1/CTLA-4 therapy for MBM management, further study of optimal selection criteria for the addition of SRS is warranted.

Low-Dose Nivolumab with or without Ipilimumab as Adjuvant Therapy Following the Resection of Melanoma Metastases: A Sequential Dual Cohort Phase II Clinical Trial

Simple Summary

Optimal dosing and duration of adjuvant treatment with PD-1 immune checkpoint inhibitors in melanoma patients have not been established. The investigated low-dose regimen of nivolumab with or without ipilimumab (in a sequential dual-cohort phase II trial), resulted in a 12-months relapse-free survival (RFS) rate and tolerability that was comparable to what has been served with standard dosing of nivolumab or pembrolizumab when patients were matched for stage. The incidence of immune-related adverse events was similar to what has been reported from registration trials in this indication. Immunohistochemical quantification of intra- and peritumoral immune cells, but not PD-1/PD-L1 staining, correlated significantly with RFS. Therefore, low-dose regimes of PD-1 blocking monoclonal antibodies deserve further study as cost-effective alternatives for currently approved standard dosing regimens, with baseline immunohistochemical tumor profiling to be further explored as a promising biomarker.

Abstract

Background: Optimal dosing and duration of adjuvant treatment with PD-1 and CTLA-4 immune checkpoint inhibitors have not been established. Prior to their regulatory approval we investigated a low-dose regimen of nivolumab with or without ipilimumab in a sequential dual-cohort phase II clinical trial. Methods: Following the complete resection of melanoma metastases, patients were treated with a single fixed dose of ipilimumab (50 mg) plus 4 bi-weekly fixed doses of nivolumab (10 mg) (cohort-1), or nivolumab for 1 year (10 mg fixed dose, Q2w x9, followed by Q8w x4) (cohort-2). Twelve-months relapse-free survival (RFS) served as the primary endpoint. Results: After a median follow-up of 235 weeks for cohort-1 (34 patients), and 190 weeks for cohort-2 (21 patients), the 12-months RFS-rate was, respectively, 55.9% (95% CI, 39–72), and 85.7% (95% CI, 70–100). Treatment-related adverse events occurred in 27 (79%), and 18 (86%) patients, with 3 (9%), and 1 (5%) grade 3 adverse events in cohort-1 and -2, respectively. Immunohistochemical quantification of intra- and peritumoral CD3⁺ T cells and CD20⁺ B cells, but not PD-1/PD-L1 staining, correlated significantly with RFS. Conclusions: One year of adjuvant low-dose nivolumab could be an effective and economically advantageous alternative for standard dosing, at the condition of further confirmation in a larger patient cohort. A shorter low-dose nivolumab plus ipilimumab regimen seems inferior and less tolerable.

Defining unique clinical hallmarks for immune checkpoint inhibitor-based therapies

Introduction

Immuno-oncology therapies, including immune checkpoint inhibitors (ICIs), have transformed cancer care and have brought into question whether classic oncology efficacy assessments adequately describe the distinctive responses observed with these agents. With more ICI-based therapies being approved across multiple tumor types, it is essential to define unique clinical hallmarks of these agents and their associated assessments to better reflect the therapeutic impact for both patients and physicians. Long-term survival and objective responses, such as depth and durability of responses, treatment-free survival, efficacy in brain metastases, improved health-related quality of life, and unique safety profiles, are among the hallmarks that have emerged for ICI therapies. An established clinical hallmark is a sustained long-term survival, as evidenced by a delayed separation of Kaplan-Meier survival curves, and a plateau at ~3 years. Combination ICI therapies provide the opportunity to raise this plateau, thereby affording durable survival benefits to more patients. Deepening of responses over time is a unique clinical ICI hallmark, with patients responding long term and with more durable complete responses. Depth of response has demonstrated prognostic value for long-term survival in some cancers, and several ICI studies have shown sustained responses even after discontinuing ICI therapy, offering the potential for treatment-free intervals. Although clinical evidence supporting efficacy in brain metastases is limited, favorable ICI intracranial responses have been seen that are largely concordant with extracranial responses. While patient outcomes can be significantly improved with ICIs, they are associated with unique immune-mediated adverse reactions (IMARs), including delayed ICI toxicities, and may require multidisciplinary management for optimal care. Interestingly, patients discontinuing ICIs for IMARs may maintain responses similar to patients who did not discontinue for an IMAR, whether they restarted ICI therapy or not.

Conclusion

Herein, we comprehensively review and refine the clinical hallmarks uniquely associated with ICI therapies, which not only will rejuvenate our assessment of ICI therapeutic outcomes but also will lead to a greater appreciation of the effectiveness of ICI therapies.

Infections in Hospitalized Cancer Patients

Cancer patients are at an increased risk of developing infections that are primarily treatment-driven but may also be malignancy-driven. While cancer treatments such as chemotherapy, radiotherapy, and surgery have been known to improve malignancy morbidity and mortality, they also have the potential to weaken immune defenses and induce periods of severe cytopenia. These adverse effects pave the way for opportunistic infections to complicate a hospitalized cancer patient's clinical course. Understanding the risk each patient inherently has for developing a bacterial, fungal, or viral infection is critical to choosing the correct prophylactic treatment in conjunction with their scheduled cancer therapy. This review discusses the most common types of infections found in hospitalized cancer patients as well as the current guidelines for prophylactic and antimicrobial treatment in cancer patients. In addition, it describes the interaction between antibiotics and cancer therapies for consideration when treating infection in a cancer patient.

Immune checkpoint-targeted antibodies: a room for dose and schedule optimization?

Anti-CTLA-4 and anti-PD-1/PD-L1 immune checkpoint inhibitors are therapeutic monoclonal antibodies that do not target cancer cells but are designed to reactivate or promote antitumor immunity. Dosing and scheduling of these biologics were established according to conventional drug development models, even though the determination of a maximum tolerated dose in the clinic could only be defined for anti-CTLA-4. Given the pharmacology of these monoclonal antibodies, their high interpatient pharmacokinetic variability, the actual clinical benefit as monotherapy that is observed only in a specific subset of patients, and the substantial cost of these treatments, a number of questions arise regarding the selected dose and the dosing interval. This review aims to outline the development of these immunotherapies and considers optimization options that could be used in clinical practice.

Toripalimab: the First Domestic Anti-Tumor PD-1 Antibody in China

Toripalimab (Tuoyi™) is a selective, recombinant, humanized monoclonal antibody against programmed death protein 1 (PD-1) developed by Shanghai Junshi Bioscience Co., Ltd. Toripalimab is able to bind to PD-1 and block the interaction with its ligands. The binding of toripalimab to PD-1 is mainly attributed to the heavy chain of the former and the FG loop of the latter. Toripalimab received a conditional approval in China for the treatment of melanoma (second-line) in December, 2018. It has also received approvals to treat nasopharyngeal carcinoma (first-line and third-line) and urothelial carcinoma (second-line) in 2021. Additionally, several orphan drug designations were granted to toripalimab by the US Food and Drug Administration. Toripalimab has exhibited primary anti-tumor effects in tumors such as melanoma, lung cancer, digestive tract tumors, hepatobiliary and pancreatic tumors, neuroendocrine neoplasms, nasopharyngeal carcinoma and urothelial carcinoma. It showed a satisfactory anti-tumor effect and long-term survival benefits in Chinese melanoma patients, while the combination of axitinib with toripalimab exhibited an impressive result in metastatic mucosal melanoma. As a checkpoint inhibitor, toripalimab was generally well-tolerated in the enrolled patients. Due to different study populations, comparisons could not be made directly between toripalimab and other drugs in most cases. Nevertheless, the introduction of toripalimab may offer a valuable choice for decision-making in the treatment of tumors in the future.

GPR182 limits antitumor immunity via chemokine scavenging in mouse melanoma models

For many solid tumors, immune checkpoint blockade therapy has become first line treatment, yet a large proportion of patients with immunologically cold tumors do not benefit due to the paucity of tumor infiltrating lymphocytes. Here we show that the orphan G Protein-Coupled Receptor 182 (GPR182) contributes to immunotherapy resistance in cancer via scavenging chemokines that are important for lymphocyte recruitment to tumors. GPR182 is primarily upregulated in melanoma-associated lymphatic endothelial cells (LECs) during tumorigenesis, and this atypical chemokine receptor endocytoses chemokines promiscuously. In GPR182-deficient mice, T cell infiltration into transplanted melanomas increases, leading to enhanced effector T cell function and improved antitumor immunity. Ablation of GPR182 leads to increased intratumoral concentrations of multiple chemokines and thereby sensitizes poorly immunogenic tumors to immune checkpoint blockade and adoptive cellular therapies. CXCR3 blockade reverses the improved antitumor immunity and T cell infiltration characteristic of GPR182-deficient mice. Our study thus identifies GPR182 as an upstream regulator of the CXCL9/CXCL10/CXCR3 axis that limits antitumor immunity and as a potential therapeutic target in immunologically cold tumors.

Immunologically cold tumours don’t respond to immune checkpoint blockade inhibition due to poor recruitment of anti-tumour T cells. Authors show here that melanoma-associated lymphatic endothelial cells express G Protein-Coupled Receptor 182 that scavenges CXCL9 and other chemokines necessary for T cell recruitment.

Pulmonary Toxicities of Immunotherapy

Immune checkpoint inhibitors are a form of immunotherapy that are increasingly being used in a wide variety of cancers. Immune-related adverse events (irAEs) pose a major challenge in the treatment of cancer patients. Pneumonitis, the most common lung irAE, can cause significant disruptions in the treatment of cancer and may be life-threatening. The goal of this chapter is to instruct readers on the incidence and clinical manifestations of pneumonitis and to offer guidance in the evaluation and treatment of patients with pneumonitis.

Hepatobiliary and Pancreatic Adverse Events

The expanded approval of immune checkpoint inhibitors (ICIs) for the treatment of multiple cancer types has offered patients more opportunities in treatment selection and survival.Hepatotoxicity is a well-recognized immune-related adverse event (irAE) associated with treatment with ICI. It is considered a type of drug-induced liver injury (DILI). Depending on the specific ICI and whether the patient receives single- or dual-drug therapy, the incidence of hepatotoxicity in general could be as high as 30%. As more patients receive treatment with ICI, more cases of hepatotoxicity are expected to occur. Clinicians must exercise close pharmacovigilance to recognize liver-related irAEs early.ICI-mediated hepatobiliary toxicity (or "IMH") generally presents as asymptomatic elevations of alanine transaminase and aspartate transaminase, with or without alkaline phosphatase elevation. Some patients may present with jaundice, fever, or malaise. Rarely, it may cause liver failure and death. The diagnosis of IMH is made after careful exclusion of other causes of acute hepatitis based on medical history, laboratory evaluation, imaging, and liver histological findings. In clinically significant cases of IMH, the management involves discontinuation of ICI followed by close monitoring and the initiation of immunosuppression. Current society guidelines, which are not based on robust evidence, specify treatment recommendations depending on the grade of liver injury, according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. However, our clinical experience suggests possible alternatives, including lower corticosteroid dosing with adjunct therapies. Whereas current guidelines endorse permanent cessation of future ICI treatment in patients diagnosed with grades 3-4 IMH, published clinical experience suggests potential for flexibility when assessing for candidacy of resuming ICI.Because histologic bile duct injury has been observed in cases ascribed to IMH, ICI-mediated cholangiopathic disease probably exists on a spectrum within IMH. Even extrahepatic bile duct involvement has been observed. This phenotype warrants special considerations in treatment and surveillance.ICI-related cholecystitis has been rarely reported in the literature. Management follows current standards of care for typical cases of cholecystitis. No relationship with ICI-mediated cholangiopathic disease has been observed.Assessing for and managing ICI-associated pancreatic injury remain challenging to the clinician. Many cases of asymptomatic serum lipase elevation are detected on routine labs without clinical signs or symptoms of typical acute pancreatitis. However, symptomatic patients should be initially managed like traditional cases of acute pancreatitis requiring hospitalization for evaluation and inpatient management.

A retrospective chart review of management strategies for lichenoid eruptions associated with immune-checkpoint inhibitor therapy from a single institution

Immune checkpoint inhibitors and their associated immune-related cutaneous adverse events are continuing to become a mainstay of cancer treatment regimens. While most rashes are mild and easily manageable, severe or persistent rashes like lichenoid dermatoses can significantly impact the quality of life and may require ICI cessation. Lichenoid dermatoses currently have no management guidelines beyond the use of topical or oral steroids. Our study is a single-institution retrospective chart review to characterize ICI-induced lichenoid eruptions, their treatments, and associated tumor response. We utilized natural language processing and our institutional medical record to identify patients with lichenoid eruptions on ICI therapy. One-hundred nineteen patients were identified, of which 108 rashes were characterized as lichenoid dermatitis and fifteen as lichenoid mucositis. Most patients presented with a diffuse distribution (86%, 101/117), with pruritus in lichenoid dermatoses (82%, 89/108) and pain in lichenoid mucositis (80%, 12/15). Successful treatments for lichenoid dermatitis included topical steroids (81%, 88/108), oral antihistamines (21%, 23/108), and oral steroids (15%, 16/108). Of lichenoid dermatitis patients, 21% (23/108) did not respond to treatment (7) or required oral steroids (16). Approximately 28% of patients who had lichenoid dermatitis had delay, reduction, or discontinuation of their ICI because of their irCAE. This descriptive study highlights the impact of lichenoid dermatitis on patients' ability to remain on ICI therapy and the need for more effective non-steroidal management strategies.

First experiences with the use of targeted and immunotherapy in the treatment of cutaneous melanoma: A single centre experience

Background / Aim: Up until ten years ago stage four melanoma was considered a disease with extremely poor prognosis. Standard therapy during this period of time was dacarbazine chemotherapy. Patients with better performance status were treated with immunotherapy cytokine IL-2. In the last ten years eight medications have been approved by the FDA for the therapy of melanoma. The goal of this study was to determine objective response rate (ORR), median overall survival (OS), median progression free survival (PFS) and safety in patients with advanced and metastatic cutaneous melanoma treated with targeted therapy and immunotherapy at the University Clinical Centre of the Republic of Srpska (Centre). Methods: A non-randomised observational retrospective/prospective trial was conducted to investigate first experiences with the use of targeted therapy and immunotherapy at the Centre and compare the results with the literature data. A total of 23 patients received BRAF targeted therapy for the treatment of metastatic cutaneous melanoma in the first line of treatment. Nine patients received vemurafenib, fourteen patients received a combination of BRAF/MEK inhibitor. Nine patients were treated with pembrolizumab immunotherapy. The trial was performed in a period from May 2017 until December 2020. Results: In patients receiving vemurafenib ORR was 44.4 %, median PFS was 5 months (95 % CI, 1 to 11) and the median OS was 9 months (95 % CI, 2 to 17). In the vemurafenib/cobimetinib group ORR was 71.4 %. Median PFS was 9 months and median OS was 12 months. ORR in patients receiving pembrolizumab was 22.9 %, median PFS was 3 months (95 % CI, 1 to 11) and the median OS was 4.5 months (95 % CI, 2 to 12). Results in all three groups were inferior compared to the results from the literature except for ORR in patients receiving vemurafenib and vemurafenib/cobimetinib. Adverse events were tolerable and manageable and were similar to those described in the literature. Conclusion: Based on the experience with the targeted and immunotherapy in the Centre, which was presented in this study, it was concluded that in conditions when there is limited access to drugs, the greatest benefit have the patients who meet the inclusion criteria in clinical trials.

Interleukin-8 in Melanoma Pathogenesis, Prognosis and Therapy-An Integrated View into Other Neoplasms and Chemokine Networks

Cutaneous melanoma accounts for only about 7% of skin cancers but is causing almost 90% of deaths. Melanoma cells have a distinct repertoire of mutations from other cancers, a high plasticity and degree of mimicry toward vascular phenotype, stemness markers, versatility in evading and suppress host immune control. They exert a significant influence on immune, endothelial and various stromal cells which form tumor microenvironment. The metastatic stage, the leading cause of mortality in this neoplasm, is the outcome of a complex, still poorly understood, cross-talk between tumor and other cell phenotypes. There is accumulating evidence that Interleukin-8 (IL-8) is emblematic for advanced melanomas. This work aimed to present an updated status of IL-8 in melanoma tumor cellular complexity, through a comprehensive analysis including data from other chemokines and neoplasms. The multiple processes and mechanisms surveyed here demonstrate that IL-8 operates following orchestrated programs within signaling webs in melanoma, stromal and vascular cells. Importantly, the yet unknown molecularity regulating IL-8 impact on cells of the immune system could be exploited to overturn tumor fate. The molecular and cellular targets of IL-8 should be brought into the attention of even more intense scientific exploration and valorization in the therapeutical management of melanoma.

Efficacy of ipilimumab and nivolumab in patients with high-grade neuroendocrine neoplasms

Background

Dual checkpoint inhibitor therapy with anti-programmed cell death protein 1 and anti-cytotoxic T-lymphocyte-associated protein 4 therapy has shown promising results in patients with high-grade neuroendocrine neoplasms (NENs), demonstrating varying response rates of 9%-44%. More data are needed to evaluate the true response in a real-world cohort of patients.

Patients and methods

We conducted a retrospective study of all patients with high-grade NENs treated at the Moffitt Cancer Center and Mayo Clinic between September 2017 and July 2020 who received combination therapy with ipilimumab and nivolumab.

Results

Thirty-four patients met the eligibility criteria. Patients had received an average of two prior lines of therapy, including at least one cytotoxic chemotherapy regimen. Twenty-seven (79.4%) patients had poorly differentiated neuroendocrine carcinomas, and seven (20.6%) had well-differentiated high-grade neuroendocrine tumors. The most common primary site (10, 29.4%) was pancreas; other primary sites of disease included colon (n = 5), endometrium (n = 3), anorectum (n = 2), esophagus (n = 2), cervix (n = 1), stomach (n = 1), small intestine (n = 1), and unknown primary (n = 9). Five patients (14.7%) exhibited a best response of partial response as per RECIST 1.1 criteria, 9 (26.5%) stable disease, and 17 (50%) progressive disease: 3 patients did not have a follow-up scan as they discontinued treatment shortly after initiation due to clinical progression. The objective response rate was 14.7%, and disease control rate was 41.2%. Median progression-free survival was 1 month [95% confidence interval (CI), 0.54-1.46 months]; median overall survival (OS) from time of treatment initiation was 5.0 months (95% CI, 4.07-5.93 months), and median OS from diagnosis was 14.0 months (95% CI, 11.79-16.21 months). The median duration of treatment was 1 month (range 0-10 months). Twenty-eight patients discontinued treatment for progression, four patients for toxicity, and two remain on treatment at the time of data cut-off. Twelve patients (35%) experienced grade 3 and 4 treatment-emergent toxicities.

Conclusions

The ipilimumab and nivolumab regimen has modest activity in aggressive and heavily pretreated high-grade NENs who have progressed on prior cytotoxic chemotherapy.

•

Dual checkpoint inhibitor therapy has shown promising results in high-grade NENs.

•

Thirty-four patients with progressive high-grade NENs were treated with ipilimumab and nivolumab.

•

The objective response rate was 14.7%; 35% of patients experienced grade 3-4 treatment-emergent toxicities.

•

The ipilimumab and nivolumab regimen has modest activity in aggressive and heavily pretreated high-grade NENs.

Rational administration sequencing of immunochemotherapy elicits powerful anti-tumor effect

As a research hotspot, immune checkpoint inhibitors (ICIs) is often combined with other therapeutics in order to exert better clinical efficacy. To date, extensive laboratory and clinical investigations into the combination of ICIs and chemotherapy have been carried out, demonstrating augmented effectiveness and broad application prospects in anti-tumor therapy. However, the administration of these two treatment modalities is usually randomized or fixed to a given chronological order. Nevertheless, the pharmacological effect of drug is closely related to its exposure behavior in vivo, which may consequently affect the synergistic outcomes of a combined therapy. In this study, we prepared a lipid nanoparticle encapsulating docetaxel (DTX-VNS), and associated it with the immune checkpoint inhibitor anti-PD-1 antibody (αPD-1) for the treatment of malignant tumors. To identify the optimum timing and sequencing for chemotherapy and immunotherapy, we designed three administration regimes, including the simultaneous delivery of DTX-VNS and αPD-1(DTX-VNS@αPD-1), DTX-VNS delivery before (DTX-VNS plus αPD-1) or post (αPD-1 plus DTX-VNS) PD-1 blockade with an interval of two days. Analysis from mass spectrometry, multi-factor detection and other techniques indicated that DTX-VNS plus αPD-1 initiated a powerful anti-tumor response in multiple tumor models, contributing to a remarkably reshaped tumor microenvironment landscape, which may attribute to the maximum therapeutic additive effects arise from a concomitant exposure of DTX-VNS and αPD-1 at the tumor site. By profiling the exposure kinetics of nanoparticles and αPD-1 in vivo, we defined the administration schedule with utmost therapeutic benefits, which may provide a valuable clinical reference for the rational administration of immunochemotherapy.

Analysis of human glioma-associated co-inhibitory immune checkpoints in glioma microenvironment and peripheral blood

One biomarker for a better therapeutic effect of immune checkpoint inhibitors is high expression of checkpoint in tumor microenvironment The purpose of this study is to investigate the expression of immune checkpoints in human glioma microenvironment and peripheral blood mononuclear cells. First, single-cell suspension from 20 fresh high-grade glioma (HGG) specimens were obtained, and analyzed for lymphocyte composition, then six co-inhibitory immune checkpoints were analyzed at the same time. Second, 36 PBMC specimens isolated from HGG blood samples were analyzed for the same items. In GME, there were four distinct subtypes of cells, among them, immune cells accounted for an average of 51.3%. The myeloid cell population (CD11b⁺) was the most common immune cell identified, accounting for 36.14% on average; the remaining were most CD3⁺CD4⁺ and CD3⁺/CD8⁻/CD4⁻ T lymphocytes. In these cells, we detected the expression of BTLA, LAG3, Tim-3, CTLA-4, and VISTA on varying degrees. While in PBMCs, the result showed that when compared with healthy volunteers, the proportion of NK cells decreased significantly in HGG samples (p < 0.01). Moreover, the expression of BTLA, LAG3, and Tim-3 in CD45⁺ immune cells in PBMC was more remarkable in glioma samples. In conclusion, the CD11b⁺ myeloid cells were the predominant immune cells in GME. Moreover, some immune checkpoints displayed a more remarkable expression on the immune cells in GME. And the profile of checkpoint expression in PBMC was partially consistent with that in GME.

Signal pathways of melanoma and targeted therapy

Melanoma is the most lethal skin cancer that originates from the malignant transformation of melanocytes. Although melanoma has long been regarded as a cancerous malignancy with few therapeutic options, increased biological understanding and unprecedented innovations in therapies targeting mutated driver genes and immune checkpoints have substantially improved the prognosis of patients. However, the low response rate and inevitable occurrence of resistance to currently available targeted therapies have posed the obstacle in the path of melanoma management to obtain further amelioration. Therefore, it is necessary to understand the mechanisms underlying melanoma pathogenesis more comprehensively, which might lead to more substantial progress in therapeutic approaches and expand clinical options for melanoma therapy. In this review, we firstly make a brief introduction to melanoma epidemiology, clinical subtypes, risk factors, and current therapies. Then, the signal pathways orchestrating melanoma pathogenesis, including genetic mutations, key transcriptional regulators, epigenetic dysregulations, metabolic reprogramming, crucial metastasis-related signals, tumor-promoting inflammatory pathways, and pro-angiogenic factors, have been systemically reviewed and discussed. Subsequently, we outline current progresses in therapies targeting mutated driver genes and immune checkpoints, as well as the mechanisms underlying the treatment resistance. Finally, the prospects and challenges in the development of melanoma therapy, especially immunotherapy and related ongoing clinical trials, are summarized and discussed.

Prognostic value of 2-[18F]FDG PET-CT in metastatic melanoma patients receiving immunotherapy

PURPOSE

The 2-fluorodeoxyglucose positron emission tomography/computed tomography (2-[¹⁸F]FDG PET/CT) is used for the evaluation of response to immunotherapy in malignant melanoma. Here, we evaluated the prognostic value of various metabolic parameters in baseline and different time points after therapy.

METHODS

In this retrospective study, 51 metastatic melanoma patients, who had received immunotherapy, were included. Patients with baseline and two follow-up 2-[¹⁸F]FDG PET/CT studies (3 and 6 months after therapy) were selected. Multiple metabolic parameters and tumor-to-background ratios (TBRs) were extracted and correlated with OS.

RESULTS

The 3- and 5-year OS rates were 49% and 43.1%, respectively. On baseline 2-[¹⁸F]FDG PET/CT, only standardized uptake value corrected for lean body mass (SUL_max and SUL_peak), as well as most of the TBRs were predictive for 3- and 5-year OS rates. Metabolic tumor volume (MTV), total lesion glycolysis (TLG), and most of the TBRs were predictive on both follow-up studies. Also, the changes in values of MTV, TLG and most of the TBRs from the baseline to the 3-month and 6- month follow-up studies were prognostic. On multivariate analysis, all of the most predictive parameters for OS were derived from the 3-month follow-up study. The ratio of TBR_mean to the mediastinum was the best factor (cutoff value of 2.15, sensitivity of 88.5% and specificity of 68.0% for 3-year survival).

CONCLUSION

Metabolic parameters derived from 2-[¹⁸F]FDG PET/CT are valuable tools for the prediction of 3- and 5-year OS rates in metastatic melanoma patients undergoing immunotherapy. The 3-month follow-up 2-[¹⁸F]FDG PET/CT is of particular importance in this regard.

Protein phosphatase 2A inactivation induces microsatellite instability, neoantigen production and immune response

Microsatellite-instable (MSI), a predictive biomarker for immune checkpoint blockade (ICB) response, is caused by mismatch repair deficiency (MMRd) that occurs through genetic or epigenetic silencing of MMR genes. Here, we report a mechanism of MMRd and demonstrate that protein phosphatase 2A (PP2A) deletion or inactivation converts cold microsatellite-stable (MSS) into MSI tumours through two orthogonal pathways: (i) by increasing retinoblastoma protein phosphorylation that leads to E2F and DNMT3A/3B expression with subsequent DNA methylation, and (ii) by increasing histone deacetylase (HDAC)2 phosphorylation that subsequently decreases H3K9ac levels and histone acetylation, which induces epigenetic silencing of MLH1. In mouse models of MSS and MSI colorectal cancers, triple-negative breast cancer and pancreatic cancer, PP2A inhibition triggers neoantigen production, cytotoxic T cell infiltration and ICB sensitization. Human cancer cell lines and tissue array effectively confirm these signaling pathways. These data indicate the dual involvement of PP2A inactivation in silencing MLH1 and inducing MSI.

Cancer Therapy Targeting CD47/SIRPα

Simple Summary

The interaction between cluster of differentiation 47 (CD47) on cancer cells and signal regulatory protein alpha (SIRPα) on immune cells, such as macrophages and dendritic cells, generates a “don’t eat me” signal. This is a common mechanism that provides cancer cells an escape from the innate immune system. Several therapeutics directed to CD47 or SIRPα have entered early clinical trials in recent years. In this article, we review the role of CD47/SIRPα axis in cancer, and summarize the literature on the efficacy and safety of therapeutics targeting CD47 or SIRPα. We also discuss the future implementation of these therapeutics in the treatments of various cancer types.

Abstract

In the past decade, the field of cancer immunotherapy has rapidly advanced, establishing a crucial role for immune checkpoint blockers in the treatment of a variety of cancer types. In parallel with these remarkable clinical developments, further efforts have focused on ways of unleashing adaptive immune responses against cancer. CD47, a cell surface molecule overexpressed by several cancer types that facilitates immune escape from macrophages, dendritic cells and natural killer cells, and its ligand SIRPα, have emerged as potential therapeutic targets. A number of agents directed to CD47/SIRPα have been developed and demonstrated preclinical activity. Early phase clinical trials are investigating CD47/SIRPα directed agents with available data, suggesting safety and preliminary activity. Herein, we provide an overview of the mechanistic rationale of targeting CD47/SIRPα axis and associated clinical evidence.

Interacting Genetic Lesions of Melanoma in the Tumor Microenvironment: Defining a Viable Therapy

Melanoma is the most aggressive form of skin cancer with an estimated 106,110 newly diagnosed cases in the United States of America in 2021 leading to an approximated 7180 melanoma-induced deaths. Cancer typically arises from an accumulation of somatic mutations and can be associated with mutagenic or carcinogenic exposure. A key characteristic of melanoma is the extensive somatic mutation rate of 16.8 mutations/Mb, which is largely attributed to UV exposure. Bearing the highest mutational load, many of them occur in key driver pathways, most commonly the BRAFV600E in the mitogen-activated protein kinase (MAPK) pathway. This driver mutation is targeted clinically with FDA-approved therapies using small molecule inhibitors of oncogenic BRAFV600E and MEK, which has greatly expanded therapeutic intervention following a melanoma diagnosis. Up until 2011, therapeutic options for metastatic melanoma were limited, and treatment typically fell under the spectrum of surgery, radiotherapy, and chemotherapy.Attributed to the extensive mutation rate, as well as having the highest number of neoepitopes, melanoma is deemed to be extremely immunogenic. However, despite this highly immunogenic nature, melanoma is notorious for inducing an immunosuppressive microenvironment which can be relieved by checkpoint inhibitor therapy. The two molecules currently approved clinically are ipilimumab and nivolumab, which target the molecules CTLA-4 and PD-1, respectively.A plethora of immunomodulatory molecules exist, many with redundant functions. Additionally, these molecules are expressed not only by immune cells but also by tumor cells within the tumor microenvironment. Tumor profiling of these cell surface checkpoint molecules is necessary to optimize a clinical response. The presence of immunomodulatory molecules in melanoma, using data from The Cancer Genome Atlas and validation of expression in two model systems, human melanoma tissues and patient-derived melanoma cells, revealed that the expression levels of B and T lymphocyte attenuator (BTLA), TIM1, and CD226, concurrently with the BRAFV600E mutation status, significantly dictated overall survival in melanoma patients. These molecules, along with herpesvirus entry mediator (HVEM) and CD160, two molecules that are a part of the HVEM/BTLA/CD160 axis, had a higher expression in human melanoma tissues when compared to normal skin melanocytes and have unique roles to play in T cell activation. New links are being uncovered between the expression of immunomodulatory molecules and the BRAFV600E genetic lesion in melanoma. Small molecule inhibitors of the MAPK pathway regulate the surface expression of this multifaceted molecule, making BTLA a promising target for immuno-oncology to be targeted in combination with small molecule inhibitors, potentially alleviating T regulatory cell activation and improving patient prognosis.

Comparison of programmed death ligand 1 immunostaining for pancreatic ductal adenocarcinoma between paired cytological and surgical samples

Objectives:

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis with surgery or chemotherapy. Programmed death ligand 1 expression (PD-L1) immunotherapy has been successful for treating lung and other cancers with PD-L1 expression. However, in many unresectable PDAC cases, cytological samples are the only available tissues for PD-L1 testing. The aim of this study is to retrospectively compare the expression of PD-L1 using cytological and surgical samples.

Material and Methods:

Paired formalin-fixed cell blocks and surgical samples from the same patients with confirmed diagnoses of PDAC (n = 28) were sectioned for PD-L1 immunohistochemistry. Using tumor proportion score (TPS) and combined positive score (CPS) to evaluate paired cell blocks and surgical samples, we counted and analyzed the data.

Results:

With TPS, the PD-L1 was expressed in 9/28 (32%) of PDAC surgical samples and in 9/28 (32%) of paired cytological samples. Overall, the PD-L1 expression had a correlation of 26/28 (93%). With CPS, the PD-L1 was expressed in 20/28 (71%) of PDAC surgical samples and in 16/28 (57%) of paired cytological samples. The PD-L1 expression had a correlation of 20/28 (71%) and a discrepancy of 8/28 (29%). The PD-L1 expression was significantly higher in moderately-differentiated PDAC than in well-differentiated with TPS.

Conclusion:

Cytological samples are useful for evaluating PD-L1 expression with TPS because the concordant rate was 93%. With CPS, cytological samples are limited due to the scant inflammatory cells with the concordant rate of 71%. Extensive sampling of the pancreatic tumor may improve the detection of immune cells expressing PD-L1 in cytological samples. With TPS, PD-L1 expression was significantly higher in moderate-differentiation of PDAC than in poor- and well-differentiation.

Soluble PD-L1 through alternative polyadenylation works as a decoy in lung cancer immunotherapy

Immune checkpoint therapy targeting the PD-1/PD-L1 axis is a novel development in anticancer therapy and has been applied to clinical medicine. However, there are still some problems, including a relatively low response rate, innate mechanisms of resistance against immune checkpoint blockades, and the absence of reliable biomarkers to predict responsiveness. In this study of in vitro and in vivo models, we demonstrate that PD-L1-vInt4, a splicing variant of PD-L1, plays a role as a decoy in anti-PD-L1 antibody treatment. First, we showed that PD-L1-vInt4 was detectable in clinical samples and that it was possible to visualize the secreting variants with IHC. By overexpressing the PD-L1-secreted splicing variant on MC38 cells, we observed that an immune-suppressing effect was not induced by their secretion alone. We then demonstrated that PD-L1-vInt4 secretion resisted anti-PD-L1 antibody treatment, compared with wild type PD-L1, which was explicable by the PD-L1-vInt4's decoying of the anti-PD-L1 antibody. The decoying function of PD-L1 splicing variants may be one of the reasons for cancers being resistant to anti-PD-L1 therapy. Measuring serum PD-L1 levels might be helpful in deciding the therapeutic strategy.

Implementation and Effectiveness of Novel Therapeutic Substances for Advanced Malignant Melanoma in Saxony, Germany, 2010-2020-Cohort Study Based on Administrative Data

(1) Background: Targeted (TT) and immune checkpoint inhibitor (ICI) therapies have become available in the routine care of metastatic melanoma in recent years. (2) Objective: We compared mortality in patients with metastatic melanoma and different systemic therapies. (3) Methods: A retrospective cohort study, based on pseudonymized health insurance data of about two million individuals from Saxony, Germany, was conducted for the years 2010 to 2020. Only patients with an advanced stage, i.e., distant metastases were considered for the main analysis. Relative survival since metastasis and predicted survivor curves derived from a Cox model were used to assess potential differences in mortality. (4) Results: Relative survival was highest in the subgroup with sequential use of ICI and TT. All treatments except interferon had significant hazard ratios (HR) in the Cox model with time-dependent effects indicating a protective effect after treatment initiation (HR 0.01-0.146) but decreasing over time (HR 1.351-2.310). The predicted survivor curves revealed best survival under ICI-TT treatment and worst survival under TT treatment alone. (5) Conclusions: We found real-world evidence for survival benefits of patients with metastatic melanoma who received sequential ICI and TT treatment. It is conceivable that the observed high survival differences were overestimated due to bias, such as confounding by indication.

Interleukin-2, Ipilimumab, and Anti-PD-1: clinical management and the evolving role of immunotherapy for the treatment of patients with metastatic melanoma

Treatment of metastatic melanoma has changed dramatically in the past 5 years with the approval of six new agents (vemurafenib, dabrafenib, trametinib, ipilimumab, pembrolizumab, and nivolumab) by the US Food and Drug Administration (FDA). This review will compare the immunotherapies recently approved by the FDA (ipilimumab, nivolumab and pembrolizumab) with the long-approved immunotherapy, interleukin-2. Additional consideration will be given to the evolving landscape, including the opportunities for combination regimens. Immunotherapies have distinct mechanisms of action and unique response kinetics that differ from conventional cytotoxic and targeted therapies, and have a range of adverse events that can be safely managed by experienced health-care providers. Data suggest immunotherapies can result in long-term survival in a proportion of patients. This dynamic and evolving field of immunotherapy for melanoma will continue to offer challenges in terms of optimal patient management for the foreseeable future.

Pembrolizumab in endometrial cancer: Where we stand now

Recently, immunotherapy has shown promising results in solid tumors. To the best of our knowledge, this is the first systematic review of published literature synthesizing all the available data and evaluating both the efficacy and safety of pembrolizumab in endometrial cancer. The present study was performed in accordance with the PRISMA guidelines. Eligible articles were identified by searching the MEDLINE and ClinicalTrials.gov databases, using a predefined combination of the terms 'endometrial cancer' and 'pembrolizumab'. Overall, nine articles incorporating data from 712 patients were eligible. Pembrolizumab was demonstrated to be an effective and safe therapeutic option for the management of advanced/metastatic endometrial cancer. Results of ongoing trials evaluating either pembrolizumab alone or in combination with other antineoplastic regimens are expected to confirm its efficacy in this setting of patients. Pembrolizumab appears to be both durable and robust in endometrial cancer. However, there is an emerging need for novel predictive biomarkers to guide clinical practice.

Dissociated Responses in Patients with Metastatic Solid Tumors Treated with Immunotherapy

BACKGROUND

Immune checkpoint inhibitors have been demonstrated to improve overall survival. Atypical patterns of response have been reported, including dissociated response (DR). We evaluated the prevalence of DR.

PATIENTS AND METHODS

Patients had to have a baseline computed tomography (CT) scan and at least one follow-up CT scan and two target lesions (TLs). Three types of DR were evaluated using RECIST1.1: DR1, defined as at least one progressive and one responding TL; DR2, defined as at least one progressive and one stable TL; and DR3, defined as at least one stable and one responding TL.

RESULTS

A total of 1244 measurements of 272 TLs were performed in 100 patients. Forty-nine out of the 272 TLs (18%) had received old or recent radiotherapy, and 42 (15%) had been biopsied. An objective response was observed in 22 patients (22%) and on 52 TLs (19%). DR1 were observed in 8% of patients. At the tumor measurement level, the response rate was lower in the case of prior radiotherapy (29% vs 34%, p = 0.01) and higher in the case of prior biopsy (40% vs 32%, p = 0.02).

CONCLUSIONS

A DR was observed in 8% of patients. Response rate was lower in the case of prior radiotherapy and higher in the case of prior biopsy.

Neuro-Ophthalmic Complications in Patients Treated With CTLA-4 and PD-1/PD-L1 Checkpoint Blockade

BACKGROUND

In recent years, CTLA-4 and PD-1/PD-L1 checkpoint inhibitors have proven to be effective and have become increasingly popular treatment options for metastatic melanoma and other cancers. These agents work by enhancing autologous antitumor immune responses. Immune-related ophthalmologic complications have been reported in association with checkpoint inhibitor use but remain incompletely characterized. This study seeks to investigate and further characterize the neuro-ophthalmic and ocular complications of immune checkpoint blockade treatment.

METHODS

A survey was distributed through the secure electronic data collection tool REDCap to neuro-ophthalmology specialists in the North American Neuro-Ophthalmology Society listserv. The study received human subjects approval through the University of California at Los Angeles Institutional Review Board. The survey identified patients sent for neuro-ophthalmic consultation while receiving one or more of a PD-1 inhibitor (pembrolizumab, nivolumab, or cemiplimab); PD-L1 inhibitor (atezolizumab, avelumab, or durvalumab); or the CTLA-4 inhibitor ipilimumab. Thirty-one patients from 14 institutions were identified. Patient demographics, neuro-ophthalmic diagnosis, diagnostic testing, severity, treatment, clinical response, checkpoint inhibitor drug used, and cancer diagnosis was obtained.

RESULTS

The checkpoint inhibitors used in these patients included pembrolizumab (12/31), nivolumab (6/31), combined ipilimumab with nivolumab (7/31, one of whom also received pembrolizumab during their course of treatment), durvalumab (3/31), ipilimumab (2/31), and cemiplimab (1/31). Malignant melanoma (16/31) or nonsmall cell lung carcinoma (6/31) were the most common malignancies. The median time between first drug administration and the time of ophthalmological symptom onset was 14.5 weeks. Eleven patients had involvement of the optic nerve, 7 patients had inflammatory orbital or extraocular muscle involvement, 6 patients had ocular involvement from neuromuscular junction dysfunction, 4 patients had cranial nerve palsy, and 4 patients had non neuro-ophthalmic complications. Use of systemic corticosteroids with or without stopping the checkpoint inhibitor resulted in improvement of most patients with optic neuropathy, and variable improvement for the other ophthalmic conditions.

CONCLUSION

This study describes the variable neuro-ophthalmic adverse events associated with use of immune checkpoint inhibitors and contributes a more thorough understanding of their clinical presentations and treatment outcomes. We expect this will increase awareness of these drug complications and guide specialists in the care of these patients.

Conditional PD-1/PD-L1 Probody Therapeutics Induce Comparable Antitumor Immunity but Reduced Systemic Toxicity Compared with Traditional Anti-PD-1/PD-L1 Agents

Immune-checkpoint blockade has revolutionized cancer treatment. However, most patients do not respond to single-agent therapy. Combining checkpoint inhibitors with other immune-stimulating agents increases both efficacy and toxicity due to systemic T-cell activation. Protease-activatable antibody prodrugs, known as Probody therapeutics (Pb-Tx), localize antibody activity by attenuating capacity to bind antigen until protease activation in the tumor microenvironment. Herein, we show that systemic administration of anti-programmed cell death ligand 1 (anti-PD-L1) and anti-programmed cell death protein 1 (anti-PD-1) Pb-Tx to tumor-bearing mice elicited antitumor activity similar to that of traditional PD-1/PD-L1-targeted antibodies. Pb-Tx exhibited reduced systemic activity and an improved nonclinical safety profile, with markedly reduced target occupancy on peripheral T cells and reduced incidence of early-onset autoimmune diabetes in nonobese diabetic mice. Our results confirm that localized PD-1/PD-L1 inhibition by Pb-Tx can elicit robust antitumor immunity and minimize systemic immune-mediated toxicity. These data provide further preclinical rationale to support the ongoing development of the anti-PD-L1 Pb-Tx CX-072, which is currently in clinical trials.

Inhibition of estrogen signaling in myeloid cells increases tumor immunity in melanoma

Immune checkpoint blockade (ICB) therapies have significantly prolonged patient survival across multiple tumor types, particularly in melanoma. Interestingly, sex-specific differences in response to ICB have been observed, with males receiving a greater benefit from ICB than females, although the mechanism or mechanisms underlying this difference are unknown. Mining published transcriptomic data sets, we determined that the response to ICBs is influenced by the functionality of intratumoral macrophages. This puts into context our observation that estrogens (E2) working through the estrogen receptor α (ERα) stimulated melanoma growth in murine models by skewing macrophage polarization toward an immune-suppressive state that promoted CD8+ T cell dysfunction and exhaustion and ICB resistance. This activity was not evident in mice harboring macrophage-specific depletion of ERα, confirming a direct role for estrogen signaling within myeloid cells in establishing an immunosuppressed state. Inhibition of ERα using fulvestrant, a selective estrogen receptor downregulator (SERD), decreased tumor growth, stimulated adaptive immunity, and increased the antitumor efficacy of ICBs. Further, a gene signature that determines ER activity in macrophages predicted survival in patients with melanoma treated with ICB. These results highlight the importance of E2/ER signaling as a regulator of intratumoral macrophage polarization, an activity that can be therapeutically targeted to reverse immune suppression and increase ICB efficacy.

Clinical benefit of neoadjuvant anti-PD-1/PD-L1 utilization among different tumors

PD‐1/PD‐L1 (programmed cell death‐1 and programmed death‐ligand 1) inhibitors utilization in neoadjuvant therapy has been assessed in tumors. This study focused on the clinical benefits of neoadjuvant anti‐PD‐1/PD‐L1 therapy. A comprehensive search was conducted in electronic databases to identify eligible studies. Major response rate (MRR) and complete response rate (CRR) were pooled in this analysis to assess the efficacy of neoadjuvant anti‐PD‐1/PD‐L1 utilization, all grades and high‐grade adverse events (AEs) were pooled to evaluate its safety. Twenty studies were included in this meta‐analysis, with 828 patients suffering from different tumors. The pooled CRR of triple‐negative breast cancer was 0.569 (95% CI 0.514, 0.624, I² = 0%) and the pooled MRR of lung cancer was 0.471 (95% CI 0.267, 0.575, I² = 0%). The most frequent adverse event was fatigue (0.272 95% CI 0.171, 0.402, I² = 87%), and the most common high‐grade adverse event was febrile neutropenia (0.084 95% CI 0.063, 0.112, I² = 85%). In conclusion, neoadjuvant anti‐PD‐1/PD‐L1 therapy received satisfactory clinical results in these tumors included.

Clinical characteristics of gastrointestinal immune-related adverse events of immune checkpoint inhibitors and their association with survival

BACKGROUND

Despite the popularity of immune checkpoint inhibitors (ICIs) in the treatment of advanced cancer, patients often develop gastrointestinal (GI) and non-GI immune-related adverse events (irAEs). The clinical characteristics and survival outcomes of GI-irAEs have not been fully elucidated in previous reports. This necessitates the evaluation of the impact of GI-irAEs on patients receiving ICI treatment.

AIM

To evaluate the clinical characteristics of GI-irAEs and their impact on survival in patients treated with ICIs.

METHODS

In this single-center, retrospective, observational study, we reviewed the records of 661 patients who received ICIs for various cancers at Nagoya University Hospital from September 2014 to August 2020. We analyzed the clinical characteristics of patients who received ICI treatment. We also evaluated the correlation between GI-irAE development and prognosis in non-small cell lung cancer (LC) and malignant melanoma (MM). Kaplan-Meier analysis was used to compare the median overall survival (OS). Multivariate Cox proportional hazards models were used to identify prognostic factors. A P value < 0.05 was considered statistically significant.

RESULTS

GI-irAEs occurred in 34 of 605 patients (5.6%) treated with an anti-programmed cell death-1/programmed death-ligand 1 (anti-PD-1/PD-L1) antibody alone and in nine of 56 patients (16.1%) treated with an anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4) antibody alone or a combination of anti-PD-1 and anti-CTLA-4 antibodies. The cumulative incidence and median daily diarrhea frequency were significantly higher in patients receiving anti-CTLA-4 antibodies (P < 0.05). In 130 patients with MM, OS was significantly prolonged in the group that continued ICI treatment despite the development of GI-irAEs compared to the group that did not experience GI-irAEs (P = 0.035). In contrast, in 209 patients with non-small cell LC, there was no significant difference in OS between the groups. The multivariate analyses showed that a performance status of 2-3 (hazard ratio: 2.406; 95% confidence interval: 1.125–5.147; P = 0.024) was an independent predictive factor for OS in patients with MM.

CONCLUSION

Patients receiving anti-CTLA-4 antibodies develop GI-irAEs more frequently and with higher severity than those receiving anti-PD-1/PD-L1 antibodies. Continuing ICI treatment in patients with MM with GI-irAEs have better OS.

Cautious addition of targeted therapy to PD-1 inhibitors after initial progression of BRAF mutant metastatic melanoma on checkpoint inhibitor therapy

Background

Virtually all metastatic patients with metastatic melanoma who progress after initial treatment with PD-1 or CTLA-4 directed antibodies will die of their disease. Salvage options are urgently needed. It is theoretically attractive to combine immunotherapy with targeted agents in progressing patients with BRAF mutation positive melanoma, but the toxicity of combined treatment has proven challenging.

Methods

We performed a retrospective analysis of our patient database and identified 23 patients who progressed on initial checkpoint inhibitor treatment, who subsequently had cautious addition of BRAF±MEK inhibitor therapy to continued PD-1 antibody treatment.

Results

We found an objective response rate of 55% in second line therapy, with a median progression-free survival of 33.4 months and median overall survival of 34.1 months, with 40% of patients in unmaintained remission at over 3 years. Ten of 12 responding patients were able to discontinue all therapy and continue in unmaintained remission. Toxicity of this approach was generally manageable (21.7% grade 3–5 toxicity). There was 1 early sudden death for unknown reasons in a responding patient.

Discussion

Our results suggest that 2nd line therapy with PD-1 inhibitors plus BRAF±MEK inhibitors has substantial activity and manageable toxicity. This treatment can induce additional durable complete responses in patients who have progressed on initial immunotherapy. These results suggest further evaluation be performed of sequential PD-1 antibody treatment with cautious addition of targeted therapy in appropriate patients.

Engineered Removal of PD-1 From the Surface of CD19 CAR-T Cells Results in Increased Activation and Diminished Survival

CAR-T cell therapy is the most advanced way to treat therapy resistant hematologic cancers, in particular B cell lymphomas and leukemias, with high efficiency. Donor T cells equipped ex vivo with chimeric receptor recognize target tumor cells and kill them using lytic granules. CAR-T cells that recognize CD19 marker of B cells (CD19 CAR-T) are considered the gold standard of CAR-T therapy and are approved by FDA. But in some cases, CD19 CAR-T cell therapy fails due to immune suppressive microenvironment. It is shown that tumor cells upregulate expression of PD-L1 surface molecule that binds and increases level and signal provided by PD-1 receptor on the surface of therapeutic CAR-T cells. Induction of this negative signaling results in functional impairment of cytotoxic program in CAR-T cells. Multiple attempts were made to block PD-1 signaling by reducing binding or surface level of PD-1 in CAR-T cells by various means. In this study we co-expressed CD19-CAR with PD-1-specific VHH domain of anti-PD-1 nanobody to block PD-1/PD-L1 signaling in CD19 CAR-T cells. Unexpectedly, despite increased activation of CAR-T cells with low level of PD-1, these T cells had reduced survival and diminished cytotoxicity. Functional impairment caused by disrupted PD-1 signaling was accompanied by faster maturation and upregulation of exhaustion marker TIGIT in CAR-T cells. We conclude that PD-1 in addition to its direct negative effect on CAR-induced signaling is required for attenuation of strong stimulation leading to cell death and functional exhaustion. These observations suggest that PD-1 downregulation should not be considered as the way to improve the quality of therapeutic CAR-T cells.

Comparative Review of Malignant Melanoma and Histologically Well-Differentiated Melanocytic Neoplasm in the Oral Cavity of Dogs

Oral malignant melanoma (OMM) is the most common neoplasm of the canine oral cavity. It is characterized by its aggressive local disease as well as its high rate of lymphatic invasion and distant metastasis. OMM carries a poor prognosis, with most patients succumbing to the disease due to progression of the neoplasm. Histopathologically, OMM is characterized by significant nuclear atypia, a mitotic index of greater than 4/10 hpf, and evidence of vascular invasion or metastasis. Clinically, these lesions can become locally invasive, causing lysis of bones and severe inflammation of the surrounding soft tissue. With time, these lesions can spread to the regional lymph node and to the lungs and other organs. Prognosis can vary depending on the size of the primary tumor, regional node involvement, and distant metastatic disease; however, multiple studies report a relatively short median survival time ranging from less than 4 months to 8 months. Histologically well- differentiated melanocytic neoplasms (HWDMN) are a variant of OMM and sometimes referred to as canine oral melanocytic neoplasms of low malignant potential. Unlike OMM, patients with HWDMN have longer survival times. Histopathologically, HWDMNs have well-differentiated melanocytes with a low mitotic index of 3 or less per 10 hpf and minimal nuclear atypia. HWDMNs have better prognosis with a mean survival time of up to 34 months. This article is a comparative review of OMM and its less aggressive counterpart.

Physachenolide C induces complete regression of established murine melanoma tumors via apoptosis and cell cycle arrest

•

PCC and LG-134 had direct cytotoxicity in murine melanoma cell lines (IC₅₀ values ranged from 0.19–1.8 µM).

•

PCC treatment induced apoptosis of tumor cells both in vitro and in vivo.

•

PCC treatment induced G0-G1 cell cycle arrest of melanoma cells.

•

PCC treatment caused complete regression of established melanoma tumors in all mice.

•

17β-hydroxywithanolides have the potential to improve melanoma therapeutic outcome.

Melanoma is an aggressive skin cancer that metastasizes to other organs. While immune checkpoint blockade with anti-PD-1 has transformed the treatment of advanced melanoma, many melanoma patients fail to respond to anti-PD-1 therapy or develop acquired resistance. Thus, effective treatment of melanoma still represents an unmet clinical need. Our prior studies support the anti-cancer activity of the 17β-hydroxywithanolide class of natural products, including physachenolide C (PCC). As single agents, PCC and its semi-synthetic analog demonstrated direct cytotoxicity in a panel of murine melanoma cell lines, which share common driver mutations with human melanoma; the IC₅₀ values ranged from 0.19–1.8 µM. PCC treatment induced apoptosis of tumor cells both in vitro and in vivo. In vivo treatment with PCC alone caused the complete regression of established melanoma tumors in all mice, with a durable response in 33% of mice after discontinuation of treatment. T cell-mediated immunity did not contribute to the therapeutic efficacy of PCC or prevent tumor recurrence in YUMM2.1 melanoma model. In addition to apoptosis, PCC treatment induced G0-G1 cell cycle arrest of melanoma cells, which upon removal of PCC, re-entered the cell cycle. PCC-induced cycle cell arrest likely contributed to the in vivo tumor recurrence in a portion of mice after discontinuation of treatment. Thus, 17β-hydroxywithanolides have the potential to improve the therapeutic outcome for patients with advanced melanoma.

Management of Immune-Related Adverse Events in Patients Treated With Immune Checkpoint Inhibitor Therapy: ASCO Guideline Update

PURPOSE

To increase awareness, outline strategies, and offer guidance on the recommended management of immune-related adverse events (irAEs) in patients treated with immune checkpoint inhibitor (ICPi) therapy.

METHODS

A multidisciplinary panel of medical oncology, dermatology, gastroenterology, rheumatology, pulmonology, endocrinology, neurology, hematology, emergency medicine, nursing, trialists, and advocacy experts was convened to update the guideline. Guideline development involved a systematic literature review and an informal consensus process. The systematic review focused on evidence published from 2017 through 2021.

RESULTS

A total of 175 studies met the eligibility criteria of the systematic review and were pertinent to the development of the recommendations. Because of the paucity of high-quality evidence, recommendations are based on expert consensus.

RECOMMENDATIONS

Recommendations for specific organ system-based toxicity diagnosis and management are presented. While management varies according to the organ system affected, in general, ICPi therapy should be continued with close monitoring for grade 1 toxicities, except for some neurologic, hematologic, and cardiac toxicities. ICPi therapy may be suspended for most grade 2 toxicities, with consideration of resuming when symptoms revert ≤ grade 1. Corticosteroids may be administered. Grade 3 toxicities generally warrant suspension of ICPis and the initiation of high-dose corticosteroids. Corticosteroids should be tapered over the course of at least 4-6 weeks. Some refractory cases may require other immunosuppressive therapy. In general, permanent discontinuation of ICPis is recommended with grade 4 toxicities, except for endocrinopathies that have been controlled by hormone replacement. Additional information is available at www.asco.org/supportive-care-guidelines.

Response durability after cessation of immune checkpoint inhibitors in patients with metastatic Merkel cell carcinoma: a retrospective multicenter DeCOG study

BACKGROUND

Immune checkpoint inhibitors (ICI) have led to a prolongation of progression-free and overall survival in patients with metastatic Merkel cell carcinoma (MCC). However, immune-mediated adverse events due to ICI therapy are common and often lead to treatment discontinuation. The response duration after cessation of ICI treatment is unknown. Hence, this study aimed to investigate the time to relapse after discontinuation of ICI in MCC patients.

METHODS

We analyzed 20 patients with metastatic MCC who have been retrospectively enrolled at eleven skin cancer centers in Germany. These patients have received ICI therapy and showed as best overall response (BOR) at least a stable disease (SD) upon ICI therapy. All patients have discontinued ICI therapy for other reasons than disease progression. Data on treatment duration, tumor response, treatment cessation, response durability, and tumor relapse were recorded.

RESULTS

Overall, 12 of 20 patients (60%) with MCC relapsed after discontinuation of ICI. The median response durability was 10.0 months. Complete response (CR) as BOR to ICI-treatment was observed in six patients, partial response (PR) in eleven, and SD in three patients. Disease progression was less frequent in patients with CR (2/6 patients relapsed) as compared to patients with PR (7/11) and SD (3/3), albeit the effect of initial BOR on the response durability was below statistical significance. The median duration of ICI therapy was 10.0 months. Our results did not show a correlation between treatment duration and the risk of relapse after treatment withdrawal. Major reasons for discontinuation of ICI therapy were CR (20%), adverse events (35%), fatigue (20%), or patient decision (25%). Discontinuation of ICI due to adverse events resulted in progressive disease (PD) in 71% of patients regardless of the initial response. A re-induction of ICI was initiated in 8 patients upon tumor progression. We observed a renewed tumor response in 4 of these 8 patients. Notably, all 4 patients showed an initial BOR of at least PR.

CONCLUSION

Our results from this contemporary cohort of patients with metastatic MCC indicate that MCC patients are at higher risk of relapse after discontinuation of ICI as compared to melanoma patients. Notably, the risk of disease progression after discontinuation of ICI treatment is lower in patients with initial CR (33%) as compared to patients with initial PR (66%) or SD (100%). Upon tumor progression, re-induction of ICI is a feasible option. Our data suggest that the BOR to initial ICI therapy might be a potential predictive clinical marker for a successful re-induction.

Oral Immune-Related Adverse Events - Current Concepts and their Management

Recent advent of immune checkpoint inhibitors (ICIs) have made significant improvement in the treatment outcome of cancer patients. They are also known to increase the overall survival in many malignancies. They target key immune checkpoints, acting on the cytotoxic T-lymphocyte antigen-4, programmed death-1 (PD-1), and PD-1 ligand 1 pathways. ICIs are effective in cancer therapy, but also possess various adverse effects that are termed together as immune-related adverse events (irAEs). Information focusing only on the oral reactions of irAEs is scanty in the literature. Therefore, we performed a computerized database search in PubMed and Google Scholar to identify and collect data regarding the oral adverse effects of ICIs. The early recognition of oral irAEs and appropriative intervention may help in improving the quality of life in patients. This paper presents a brief review of oral irAEs and their management.

Cemiplimab in advanced cutaneous squamous cell carcinoma

Cemiplimab, a high-affinity, highly potent human monoclonal antibody that binds to the programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) receptor, is the only drug to attain Food and Drug Administration (FDA) approval and marketing authorization from the European Commission for use in patients with metastatic and locally advanced cutaneous squamous cell carcinoma (CSCC) who are not candidates for curative surgery or curative radiation therapy as a first- or later-line treatment. In pivotal phase II clinical testing, cemiplimab showed rapid and substantial antitumor efficacy and acceptable safety. This systematic review was aimed at evaluating the efficacy and safety of cemiplimab in patients with advanced CSCC. To this end, I reviewed EMBASE, MEDLINE, PubMed, and clinical trial registries/databases by using the following keywords alone or in combination: "cemiplimab," "Libtayo," "cutaneous squamous cell carcinoma," "REGN2810," and "SER439684." Cemiplimab showed clinical efficacy and considerable safety and was associated with low rates of treatment discontinuation (7%) and death (3%). However, the current recommendation is primarily based on only phase II clinical testing due to the absence of an approved comparator agent.

Effect of Immune Checkpoint Blockade on Myeloid-Derived Suppressor Cell Populations in Patients With Melanoma

Introduction

Myeloid-derived suppressor cells (MDSC) are a subset of immature myeloid cells that inhibit anti-tumor immunity and contribute to immune therapy resistance. MDSC populations were measured in melanoma patients receiving immune checkpoint inhibitors (ICI).

Methods

Patients with melanoma (n=128) provided blood samples at baseline (BL), and before cycles 2 and 3 (BC2, BC3). Peripheral blood mononuclear cells (PBMC) were analyzed for MDSC (CD33⁺/CD11b⁺/HLA- DR^lo/-) and MDSC subsets, monocytic (CD14+, M-MDSC), granulocytic (CD15+, PMN-MDSC), and early (CD14-/CD15-, E-MDSC) via flow cytometry. Statistical analysis employed unpaired and paired t-tests across and within patient cohorts.

Results

Levels of MDSC as a percentage of PBMC increased during ICI (BL: 9.2 ± 1.0% to BC3: 23.6 ± 1.9%, p<0.0001), and patients who developed progressive disease (PD) had higher baseline MDSC. In patients who had a complete or partial response (CR, PR), total MDSC levels rose dramatically and plateaued (BL: 6.4 ± 1.4%, BC2: 26.2 ± 4.2%, BC3: 27.5 ± 4.4%; p<0.0001), whereas MDSC rose less sharply in PD patients (BL: 11.7 ± 2.1%, BC2: 18.3 ± 3.1%, BC3: 19.0 ± 3.2%; p=0.1952). Subset analysis showed that within the expanding MDSC population, PMN-MDSC and E-MDSC levels decreased, while the proportion of M-MDSC remained constant during ICI. In PD patients, the proportion of PMN-MDSC (as a percentage of total MDSC) decreased (BL: 25.1 ± 4.7%, BC2: 16.1 ± 5.2%, BC3: 8.6 ± 1.8%; p=0.0105), whereas a heretofore under-characterized CD14+/CD15+ double positive MDSC subpopulation increased significantly (BL: 8.7 ± 1.4% to BC3: 26.9 ± 4.9%; p=0.0425).

Conclusions

MDSC levels initially increased significantly in responders. PMN-MDSC decreased and CD14+CD15+ MDSC increased significantly in PD patients. Changes in MDSC levels may have prognostic value in ICI.