The DNA Methylcytosine Dioxygenase Tet2 Sustains Immunosuppressive Function of Tumor-Infiltrating Myeloid Cells to Promote Melanoma Progression.

Ten-Eleven-Translocation-2 (Tet2) is a DNA methylcytosine dioxygenase that functions as a tumor suppressor in hematopoietic malignancies. We examined the role of Tet2 in tumor-tissue myeloid cells and found that Tet2 sustains the immunosuppressive function of these cells. We found that Tet2 expression is increased in intratumoral myeloid cells both in mouse models of melanoma and in melanoma patients and that this increased expression is dependent on an IL-1R-MyD88 pathway. Ablation of Tet2 in myeloid cells suppressed melanoma growth in vivo and shifted the immunosuppressive gene expression program in tumor-associated macrophages to a proinflammatory one, with a concomitant reduction of the immunosuppressive function. This resulted in increased numbers of effector T cells in the tumor, and T cell depletion abolished the reduced tumor growth observed upon myeloid-specific deletion of Tet2. Our findings reveal a non-cell-intrinsic, tumor-promoting function for Tet2 and suggest that Tet2 may present a therapeutic target for the treatment of non-hematologic malignancies.

Adjuvant PD-1 inhibitor versus high-dose interferon α-2b for Chinese patients with cutaneous and acral melanoma: A retrospective cohort analysis.

The clinical efficacy of PD-1 inhibitors as an adjuvant treatment for Asian melanoma patients has not yet been determined. This retrospective study analyzed the clinical data of 90 Chinese patients with completely resected, stage III cutaneous or acral melanoma who received either adjuvant PD-1 inhibitor or high-dose interferon α-2b (HDI). Anti-PD-1 treatment resulted in significantly longer RFS and DMFS than HDI in cutaneous melanoma patients, with hazard ratios (HRs) (anti-PD-1 versus HDI) of 0.402 (95% CI, 0.183-0.886) and 0.324 (95%CI, 0.122 to 0.861) for RFS and DMFS, respectively. However, adjuvant anti-PD-1 treatment had no advantage over HDI in acral melanoma patients with HRs (anti-PD-1 versus HDI) of 1.204 (95% CI, 0.521 to 2.781) and 1.968(95% CI, 0.744-5.209) for RFS and DMFS, respectively. Adjuvant anti-PD-1 treatment yielded a significantly better prognosis than HDI in Chinese patients with stage IIIB/C cutaneous melanoma, but a significant difference was not observed in those with acral melanoma.

Chimeric antigen receptor-modified T-cell therapy for platelet-derived growth factor receptor α-positive rhabdomyosarcoma.

BACKGROUND: New immunotherapeutic approaches are urgently needed for metastatic rhabdomyosarcoma, which is associated with poor survival and unsatisfactory treatment outcomes. Platelet-derived growth factor receptor α (PDGFRA) plays an essential role in the onset and development of rhabdomyosarcoma and is a new potential therapeutic target for rhabdomyosarcoma. The objective of this study was to generate humanized PDGFRA single-chain variable fragment-based chimeric antigen receptor (CAR)-modified T cells (CAR-T cells) against PDGFRA-positive rhabdomyosarcoma. METHODS: PDGFRA antigen expression was evaluated in specimens from patients with rhabdomyosarcoma. CAR-T cells containing a PDGFRA-specific single-chain variable fragment was developed in combination with a 4-1BB costimulatory domain and a CD3-ζ signaling domain. Specific cytotoxic effects of PDGFRA CAR-T cells, T-cell proliferation, and cytokine secretion were investigated in vitro and in vivo. RESULTS: PDGFRA CAR-T cells produced large amounts of immune-promoting cytokines, including interleukin 2, tumor necrosis factor α, and interferon γ, and exhibited efficient cytotoxic activity toward human PDGFRA-overexpressing rhabdomyosarcoma cells in vitro. In a subcutaneous xenograft model, CAR-T cells were more effective against PDGFRA-overexpressing rhabdomyosarcoma than against rhabdomyosarcoma with low PDGFRA expression in terms of tumor regression and patient survival. Expanded CAR-T cells also were detected in peripheral blood. CONCLUSIONS: The current study demonstrates for the first time that the PDGFRA antigen is a promising target for CAR-T-cell therapy in rhabdomyosarcoma and likely in a wide spectrum of other PDGFRA-expressing cancers.

Cryoablation combined with transarterial infusion of pembrolizumab (CATAP) for liver metastases of melanoma: an ambispective, proof-of-concept cohort study.

BACKGROUND: The presence of liver metastasis correlates with poor therapeutic response of PD-1 blockade therapy in melanoma. A novel treatment protocol by combining cryoablation with transarterial infusion of pembrolizumab (CATAP) was proposed, and its feasibility and safety was assessed among this group of patients. METHODS: This registered ambispective cohort study enrolled fifteen melanoma patients with multiple hepatic metastases who received planned two-stage CATAP therapy: in the combined stage, subtotal cryoablation on day 1, in which one to two intrahepatic lesions were ablated completely with other lesions left untreated, sequentially combined transarterial infusion of pembrolizumab on day 3, every three weeks, for at least one cycle; in the infusion stage, arterial infusion of pembrolizumab was recommended at three-week interval until disease progression. The primary endpoint was objective response rate by RECIST (version 1.1); secondary end points included progression-free survival (PFS) and safety; exploratory endpoints were changes of cytokines and immune cell compositions in peripheral blood samples. RESULTS: Of the 15 patients enrolled, no grade 3-4 adverse events or major complications were observed. One patient (6.7%) achieved complete response, and 3 (20.0%) achieved partial response. The overall response rates of CATAP for the entire cohort and patients with cutaneous melanoma were 26.7% (95% confidence interval (CI) 4.3-49.0%) and 33.3% (95% CI 2.5-64.1%), respectively. Clinical response was observed in a proportion of patients (2/6; 33.3%) who failed first-line intravenous pembrolizumab treatment. The median overall PFS time and hepatic PFS time were 4.0 (95% CI 2.5-5.5) and 5.73 (95% CI 1.1-10.4) months, respectively. A significant increase in CD3-CD16 + CD56 + cells (natural killer cells; P = 0.0124) and a marginally significant decrease in CD4 + CD25 + cells (regulatory T cells; P = 0.0546) were observed three weeks after the first cycle of treatment in the combined stage. CONCLUSIONS: The CATAP therapy demonstrated positive clinical activity and a favorable safety profile for melanoma patients with liver metastasis.

Time-varying pattern of recurrence risk for localized melanoma in China.

BACKGROUND: Acral and mucosal melanomas are rarely seen in Caucasians but common in China. There are limited data on the recurrence characteristics for these patients. This study aimed to identify the recurrence pattern for localized melanoma in China, especially acral and mucosal subtypes. METHODS: Patients with localized melanoma who underwent radical resection between January 1999 and December 2014 in southern China were retrospectively reviewed. Survival and annual recurrence hazard were analyzed by Kaplan-Meier method and hazard function, respectively. RESULTS: Totally, 1012 patients were included (acral melanoma 400; chronic sun-induced damage (CSD)/non-CSD melanoma 314; mucosal melanoma 298). Recurrence was recorded in 808 patients (localized 14.1%; regional 29.6%, and distant 56.3%). Mucosal melanoma had local and M1c stage recurrence more frequently than cutaneous melanoma, but less frequent regional node relapse. There was no difference in recurrent site distribution between acral and CSD/non-CSD melanoma. The annual recurrence hazard curve for the entire cohort showed a double-peaked pattern with the first major peak in the second year after surgery and the second peak near the seventh year. Mucosal melanoma had a higher recurrence risk than cutaneous melanoma. Acral melanoma had a lower flat recurrence peak than CSD/non-CSD melanoma. Tumor thickness > 4.0 mm, ulceration, positive regional nodes, and wound infection were associated with a higher recurrence risk in cutaneous melanoma. Adjuvant therapy reduced the recurrence risk of cutaneous melanoma but not of mucosal melanoma. CONCLUSIONS: This is a large cohort about the rule of recurrence risk in acral and mucosal melanoma and will provide an initial framework for development of surveillance and adjuvant strategy for Chinese melanoma patients.

Low expression of CD80 predicts for poor prognosis in patients with gastric adenocarcinoma.

AIM: To study the expression and prognostic significance of CD80 in patients with gastric adenocarcinoma. Materials & methods: Real-time quantitative PCR, western blot and immunohistochemistry were performed to detect the expression of CD80 in gastric cancer tissues and matched adjacent normal tissues. Double immunohistochemical staining was performed to preliminary examine the relationship between CD80+ cells and CD8+ cytotoxic T lymphocytes. RESULTS: The expression of CD80 was downregulated in tumor tissues compared with normal tissues (p = 0.002). Immunohistochemistry analysis showed that 49 (39.8%) of 123 patients with gastric cancer demonstrated reduced CD80 expression, which was correlated with the tumor differentiation grade. CONCLUSION: Our data suggest that reduced CD80 expression independently predicts a poor prognosis in patients with gastric adenocarcinoma.

The experience of immune checkpoint inhibitors in Chinese patients with metastatic melanoma: a retrospective case series.

Melanomas in Chinese patients show relatively higher rates of acral and mucosal types than in other populations. However, the efficacy of checkpoint inhibitor therapies against these melanoma subtypes is not well defined. We analyzed 52 patients treated with ipilimumab, pembrolizumab, or a combination of both to evaluate the efficacy and safety of checkpoint inhibitors in Chinese patients with advanced melanoma, particularly those with acral and mucosal types. The objective response rates (ORRs) were 0, 25, and 20% for ipilimumab, pembrolizumab, and pembrolizumab plus ipilimumab, respectively. Pembrolizumab contained therapy was as effective in acral and mucosal melanoma patients (ORR 26.7 and 20%, respectively) as in non-acral cutaneous melanoma patients (ORR 26.7%). Baseline lactate dehydrogenase levels and relative lymphocyte counts were independent prognostic factors for PFS and OS. The incidences of grade 3-4 adverse events were 14% in the two monotherapy groups and 30% in the combined therapy group. The most frequent adverse events were elevation of aminotransferase, skin toxicity, thyroid dysfunction, pyrexia, and fatigue. Treatment-related rash or vitiligo was associated with a better prognosis. In summary, pembrolizumab-based therapy resulted in meaningful efficacy and good tolerability in Chinese patients with melanoma, including those with acral and mucosal types.

The absence of the ERBB4 hotspot mutations in melanomas in patients from southern China.

V-erb-a erythroblastic leukemia viral oncogene homolog 4 (ERBB4) has been reported to be somatically mutated in 19% of melanoma cases. To investigate the prevalence of ERBB4 mutations in melanoma patients from southern China, we analyzed 117 formalin-fixed, paraffin-embedded melanoma samples archived in the Sun Yat-sen University Cancer Center. A matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) platform was used to screen for mutations. No ERBB4 hotspot mutations were detected. Our results indicate that ERBB4 mutations may play a limited role in melanomas in China; therefore, targeting the ERBB4 mutation in melanoma patients from southern China may not be a promising strategy.

Clinical features and response to systemic therapy in NRAS-mutant Chinese melanoma patients.

PURPOSE: The prognosis of patients with NRAS-mutant melanoma is rather poor. Immunotherapy and targeted therapy have revolutionized anti-tumor therapy, especially for melanoma. In this study, we retrospectively summarized the real-world experience of systematic treatment for NRAS-mutant melanoma patients in this new era. PATIENTS AND METHODS: The respective cohort included NRAS-mutant melanoma patients with metastatic or unresectable disease of Sun Yat-sen University Cancer Center (SYSUCC) from January 2018 to July 2022. The data about the clinical features and impact for systemic therapy of NRAS-mutant patients were collected and analyzed. RESULTS: At data cutoff, 44 patients (19, 11, and 14 for acral, cutaneous, and mucosal ones, respectively) with NRAS-mutant were assessed. In addition, the median time of follow-up was 22.0 months. The immunotherapy-based combined treatment not only significantly improved the progression-free survival (PFS) (P = 0.006, HR 0.322), but was also accompanied by a higher objective response rate (ORR) (18.2%), disease control rate (DCR) (72.7%) than those of cytotoxic therapy or immunotherapy alone for advanced patients as first-line treatment. Nab-paclitaxel combined with anti-PD-1 inhibitor tended to produce better clinical benefit for the first-line treatment, especially for patients with acral melanoma. In addition, the tyrosine kinase inhibitor (TKI) combined with anti-PD-1 inhibitor also seemed to provide longer duration of response (DOR) for some patients. But combined therapy did not prolong the overall survival (OS) of NRAS-mutant patients. The combined therapy was well tolerated. Most adverse events were moderate and controllable. CONCLUSION: In conclusion, PD-1 inhibitor-based combined therapy increased clinical benefit for advanced patients with NRAS-mutant melanoma.

Phase 1 clinical trial to assess safety and efficacy of NY-ESO-1-specific TCR T cells in HLA-A∗02:01 patients with advanced soft tissue sarcoma.

New York esophageal squamous cell carcinoma-1 (NY-ESO-1)-specific T cell receptor (TCR) T cell therapy is effective in tumors with NY-ESO-1 expression, but a safe and effective TCR-T cell therapeutic protocol remains to be improved. Here, we report a phase 1 investigational new drug clinical trial with TCR affinity-enhanced specific T cell therapy (TAEST16001) for targeting NY-ESO-1. Enrolled patients receive TAEST16001 cell infusion after dose-reduced lymphodepletion with cyclophosphamide (15 mg/kg/day × 3 days) combined with fludarabine (20 mg/m2/day × 3 days), and the TCR-T cells are maintained with low doses of interleukin-2 injection post-adoptive transfer. Analysis of 12 patients treated with the regimen demonstrates no treatment-related serious adverse events. The overall response rate is 41.7%. The median progression-free survival is 7.2 months, and the median duration of response is 13.1 months. The protocol of TAEST16001 cells delivers a safe and highly effective treatment for patients with advanced soft tissue sarcoma (ClinicalTrials.gov: NCT04318964).

A pilot study of lymphodepletion intensity for peripheral blood mononuclear cell-derived neoantigen-specific CD8 + T cell therapy in patients with advanced solid tumors.

Currently, the optimal lymphodepletion intensity for peripheral blood mononuclear cell-derived neoantigen-specific CD8 + T cell (Neo-T) therapy has yet to be determined. We report a single-arm, open-label and non-randomized phase 1 study (NCT02959905) of Neo-T therapy with lymphodepletion at various dose intensity in patients with locally advanced or metastatic solid tumors that are refractory to standard therapies. The primary end point is safety and the secondary end points are disease control rate (DCR), progression-free survival (PFS), overall survival (OS). Results show that the treatment is well tolerated with lymphopenia being the most common adverse event in the highest-intensity lymphodepletion groups. Neo-T infusion-related adverse events are only grade 1-2 in the no lymphodepletion group. The median PFS is 7.1 months (95% CI:3.7-9.8), the median OS is 16.8 months (95% CI: 11.9-31.7), and the DCR is 66.7% (6/9) among all groups. Three patients achieve partial response, two of them are in the no lymphodepletion group. In the group without lymphodepletion pretreatment, one patient refractory to prior anti-PD1 therapy shows partial response to Neo-T therapy. Neoantigen specific TCRs are examined in two patients and show delayed expansion after lymphodepletion treatment. In summary, Neo-T therapy without lymphodepletion could be a safe and promising regimen for advanced solid tumors.

An immune risk score predicts progression-free survival of melanoma patients in South China receiving anti-PD-1 inhibitor therapy-a retrospective cohort study examining 66 circulating immune cell subsets.

Introduction: Immune checkpoint blockade inhibitor (ICI) therapy offers significant survival benefits for malignant melanoma. However, some patients were observed to be in disease progression after the first few treatment cycles. As such, it is urgent to find convenient and accessible indicators that assess whether patients can benefit from ICI therapy. Methods: In the training cohort, flow cytometry was used to determine the absolute values of 66 immune cell subsets in the peripheral blood of melanoma patients (n=29) before treatment with anti-PD-1 inhibitors. The least absolute shrinkage and selection operator (LASSO) Cox regression model was followed for the efficacy of each subset in predicting progression-free survival. Then we validated the performance of the selected model in validation cohorts (n=20), and developed a nomogram for clinical use. Results: A prognostic immune risk score composed of CD1c+ dendritic cells and three subsets of T cells (CD8+CD28+, CD3+TCRab+HLA-DR+, CD3+TCRgd+HLA-DR+) with a higher prognostic power than individual features (AUC = 0.825). Using this model, patients in the training cohort were divided into high- and low-risk groups with significant differences in mean progression-free survival (3.6 vs. 12.3 months), including disease control rate (41.2% vs. 91.7%), and objective response rate (17.6% vs. 41.6%). Integrating four-immune cell-subset based classifiers and three clinicopathologic risk factors can help to predict which patients might benefit from anti-PD-1 antibody inhibitors and remind potential non-responders to pursue effective treatment options in a timely way. Conclusions: The prognostic immune risk score including the innate immune and adaptive immune cell populations could provide an accurate prediction efficacy in malignant melanoma patients with ICI therapy.

Next-generation sequencing in advanced Chinese melanoma reveals therapeutic targets and prognostic biomarkers for immunotherapy.

Limited studies have interrogated the genomic landscape of Chinese melanoma in which acral and mucosal melanoma are the mainstay. In this study, we carried out a retrospective analysis on 81 Chinese melanoma patients (15 acral, 25 mucosal and 41 cutaneous melanoma). With the identification of 1114 mutations spanning 248 genes, we summarized that the mutation spectrum varied significantly by subtypes. Acral melanoma and mucosal melanoma had significantly more CNVs. MYC amplification was one of the most commonly detected CNVs, other frequent CNVs in mucosal melanoma included NBN and KDR, which were associated with the poor survival of melanoma patients. A generally low TMB, with a median of only 5.1 mut/Mb, was observed in three groups including cutaneous melanoma. Additionally, over 50% variants in DNA damage repair pathway were detected in all three subtypes, most of which were HRD related genes. Patients with alterations of HRD related genes had a longer survival time after immunotherapy. This study revealed a molecular profiling of Chinese patients with advanced melanoma, and proposed the high variant rate in DDR pathway as a biomarker of immunotherapy, which might provide therapeutic targets and guidance in making clinical decision for different Chinese melanoma.

HHLA2 predicts improved prognosis of anti-PD-1/PD-L1 immunotherapy in patients with melanoma.

Background: As a recognized highly immunogenic tumor, immune checkpoint blockades (ICB) have been widely used as a systemic treatment option for melanoma. However, only about half of treated patients could benefit from it in Caucasians, and only about 15% in Chinese melanoma patients. Robust predictive biomarkers are needed. HHLA2, a new-found member of B7 family, is generally expressed in kinds of tumors, such as melanoma. This study focuses on illustrating the prognostic value of HHLA2 in melanoma immunotherapy and its association with tumor-infiltrating lymphocytes. Methods: HHLA2 expression in pan-cancer and the association with prognosis and immune microenvironment were identified by analyzing gene expression profiles from TCGA database with selected bioinformatics tools and methods. Tumor tissues from 81 cases with advanced and unresectable melanoma were collected for detecting HHLA2 and CD8 levels by immunohistochemistry. Results: HHLA2 was found to be ubiquitously expressed in pan-cancer with high level and correlate with the prognosis of patients. Further comprehensive analysis from TCGA database demonstrated that the highly expressed HHLA2 was remarkably correlated with better prognosis, high infiltration status of various immune-active cells and immune activated pathways in skin cutaneous melanoma (SKCM). Moreover, immunohistochemistry (IHC) analyses of FFPE tissue from melanoma patients revealed that HHLA2 high expression was strongly related to improved response to ICB and indicated a longer progression-free survival (PFS) and overall survival (OS). Besides, HHLA2 expression was found to have a positive association with the density of CD8+ TILs. Conclusion: Our findings revealed that high expression of HHLA2 has important values in predicting the response to ICB and indicating improved PFS and OS in patients with advanced and unresectable melanoma, suggesting that HHLA2 may serve as a costimulatory ligand in melanoma, which renders it as an ideal biomarker for immunotherapy.

Nomogram for predicting prognosis of patients with metastatic melanoma after immunotherapy: A Chinese population-based analysis.

Background: Previous studies indicated the evidence that baseline levels of thyroid antibodies, thyroid status, and serum lactate dehydrogenase (LDH) and M stage may influence the prognosis of patients with advanced or metastatic melanoma treated with immune checkpoint inhibitors that targets programmed cell death-1 (PD-1) or programmed death ligand 1, which reported that dramatic improvements in survival rates were observed; however, the presence of controversy has prevented consensus from being reached. Study objectives were to develop a nomogram to identify several prognostic factors in Chinese patients with metastatic melanoma receiving immunotherapy. Methods: This retrospective study included 231 patients from Sun Yat-sen University Cancer Center, and patients were split into internal cohort (n = 165) and external validation cohort (n = 66). We developed a nomogram for the prediction of response and prognosis on the basis of the levels of serum thyroid peroxidase antibody (A-TPO), free T3 (FT3), and LDH and M stage that were measured at the baseline of anti-PD-1 infusion. In addition, the follow-up lasted at least until 5 years after the treatment or mortality. RECIST v1.1 was used to classify treatment responses. Results: Chi-square test showed that PD-1 antibody was more effective in patients with melanoma with high level baseline FT4 or earlier M stage. A multivariate Cox analysis showed that baseline FT3 (P = 0.009), baseline A-TPO (P = 0.016), and LDH (P = 0.013) levels and M stage (P < 0.001) independently predicted overall survival (OS) in patients with melanoma. The above factors are integrated, and a prediction model is established, i.e., nomogram. Survival probability area-under-the-curve values of 1, 2, and 3 years in the training, internal validation, and external validation cohorts showed the prognostic accuracy and clinical applicability of nomogram (training: 0.714, 0.757, and 0.764; internal validation: 0.7171963, 0.756549, and 0.7651486; external validation: 0.748, 0.710, and 0.856). In addition, the OS of low-risk (total score ≤ 142.65) versus high-risk (total score > 142.65) patients varied significantly in both training group (P < 0.0001) and external validation cohort (P = 0.0012). Conclusions: According to this study, baseline biomarkers are associated with response to immunotherapy and prognosis among patients with metastatic melanoma. Treatment regimens can be tailor-made on the basis of these biomarkers.

Phase I study of pegylated liposomal doxorubicin and cisplatin in patients with advanced osteosarcoma.

PURPOSE: The repeated use of doxorubicin is limited due to dose-limiting cardiac toxicity. Pegylated liposomal doxorubicin (PEG-LD, Duomeisu) has a reduced cardiac toxicity. This phase I study aimed to investigate the maximum tolerated doses (MTDs) and dose-limiting toxicities (DLTs) of the PEG-LD and cisplatin combination in patients with metastatic and recurrent osteosarcoma. METHODS: Patients were given PEG-LD at a dose of 40, 50, or 60 mg/m2 on day 1 of each 21-day cycle, according to a 3 + 3 approach for dose escalation. Cisplatin was administered as a fixed dose of 100 mg/m2 for every cycle. Toxicities and tumor response were observed. RESULTS: A total of 15 patients were enrolled in this trial, and nine of the patients had received prior doxorubicin. The MTD of PEG-LD was reached at 50 mg/m2 in this regimen, with neutropenic fever and stomatitis as DTLs. The main adverse event (AE) was myelosuppression. The most common non-hematological AEs were vomiting, hypoproteinemia, stomatitis and transient sinus arrhythmia. Grade 3-4 toxicity was neutropenia, leukopenia, thrombocytopenia, anemia and stomatitis in the whole cohort. All the AEs were relieved after symptomatic and supportive treatment. Totally, the overall response rate was 13.3% and disease control rate was 66.7%. For the six patients who have not received prior doxorubicin, one partial response and five stable diseases were observed. CONCLUSION: We provide the data showing that PEG-LD 50 mg/m2 combined with cisplatin 100 mg/m2 demonstrated an acceptable safety profile and promising clinical activity in advanced osteosarcoma, which merits further evaluation in phase II studies. TRIAL REGISTRATION: ChiCTR1900021550.

Efficacy and safety of anti-PD-1 inhibitor combined with nab-paclitaxel in Chinese patients with refractory melanoma.

PURPOSE: This retrospective study aimed to evaluate the combined effect of anti-PD-1 inhibitor and nanoparticle albumin-bound (nab)-paclitaxel for refractory melanoma among Chinese patients. METHODS: Data from January 2018 to March 2021 were retrospectively collected and analyzed. Sixty-four patients were eligible for analysis from a single Chinese cancer center. RESULTS: The median follow-up was 16.0 months at data cutoff. The objective response rate (ORR) was 29.7%, and the disease control rate (DCR) was 67.2% in all patients. Treatment-naïve patients had significantly higher ORR than pretreated patients (42.9% vs 13.8%, p = 0.011). Cutaneous melanoma patients with NRAS gene mutation benefited more than non-mutated patients (DCR of 100% vs. 54.5%) (p = 0.030). The median progression-free survival (mPFS) of all patients was 5.2 months and the duration of response was 10.8 months. Median duration of disease control was 7.7 months. Prior treatment-naïve patients had significantly longer PFS than those who accepted prior treatments (7.2 vs. 5.1 months, p = 0.024). Patients with abnormally high LDH level had shorter mPFS (3.6 months vs. 6.6 months, p = 0.020). Median overall survival was not reached in this study. Most patients experienced adverse events (AEs), but only 17.2% of patients experienced grade 3 severe AEs. The most common AEs were alopecia (89.1%), neutropenia (18.8%), pruritus (15.6%), and arthralgia (14.1%). Some patients had immune related AEs (irAEs). No grade 4 or 5 AEs were observed. Patients with ≥ 3 AEs or with irAEs had longer mPFS (p < 0.05). CONCLUSION: Nab-paclitaxel combined with PD-1 antibody is a well-tolerated and effective regimen for Chinese patients with refractory melanoma.

Pembrolizumab in Chinese patients with advanced melanoma: 3-year follow-up of the KEYNOTE-151 study.

Survival is generally poor for Chinese patients with advanced melanoma because of high rates of acral and mucosal melanoma and limited therapeutic options. The first analysis of the phase 1b KEYNOTE-151 study showed second-line pembrolizumab was well tolerated and had clinically meaningful antitumor activity in Chinese patients with advanced melanoma. Three-year follow-up is presented. Eligible patients were of Chinese descent and had unresectable stage III/IV melanoma that progressed after first-line therapy. Patients received pembrolizumab 2 mg/kg every 3 weeks for ≤35 cycles. Primary end points were safety and objective response rate (ORR). Secondary end points included duration of response (DOR), progression-free survival (PFS), and overall survival (OS). Response was assessed per RECIST v1.1 by blinded independent central review. Subgroup analyses were conducted by melanoma subtype and BRAF and PD-L1 status (acral melanoma only). 103 patients were enrolled; median follow-up duration (time from first dose to data cutoff [July 13, 2020]) was 44.6 months (IQR, 39.1-46.2). Any-grade treatment-related adverse events (TRAEs) occurred in 85.4% of patients, and grade 3/4 TRAEs in 12.6%. No grade 5 TRAEs occurred. Three patients discontinued pembrolizumab because of TRAEs (immune-mediated hepatitis, pneumonia, and arthritis). Immune-mediated AEs and infusion reactions occurred in 34.0% (grade 3/4, 2.9%). ORR was 17.6% (95% CI, 10.8-26.4; 1 complete response/17 partial responses), and median DOR was 13.8 months (range, 2.7-37.4+). Median PFS was 2.8 months (95% CI, 2.7-3.5) and 36-month PFS rate was 5.0%. Median OS was 13.2 months (95% CI, 10.4-16.5) and 36-month OS rate was 22.3%. Median OS for patients with known melanoma subtype was 14.8 months for acral, 13.5 months for nonacral cutaneous, and 7.4 months for mucosal melanoma. Among the acral subgroup, median OS was 22.8 months for PD-L1-positive disease, 8.4 months for PD-L1-negative disease, 18.5 months for BRAF wild-type disease, and 5.8 months for BRAF-mutant disease. Over 3 years' follow-up, second-line pembrolizumab continued to show manageable safety, clinically meaningful antitumor activity, and durable responses in Chinese patients with advanced melanoma. Subgroup analysis suggested particular benefit in PD-L1-positive and BRAF wild-type acral melanoma, although small subgroup sizes preclude definitive conclusions. Clinical trial registration: https://clinicaltrials.gov, identifier NCT02821000.

Defined tumor antigen-specific T cells potentiate personalized TCR-T cell therapy and prediction of immunotherapy response.

Personalized immunotherapy targeting tumor-specific antigens (TSAs) could generate efficient and safe antitumor immune response without damaging normal tissues. Although neoantigen vaccines have shown therapeutic effect in clinic trials, precise prediction of neoantigens from tumor mutations is still challenging. The host antitumor immune response selects and activates T cells recognizing tumor antigens. Hence, T cells engineered with T-cell receptors (TCRs) from these naturally occurring tumor antigen-specific T (Tas) cells in a patient will target personal TSAs in his/her tumor. To establish such a personalized TCR-T cell therapy, we comprehensively characterized T cells in tumor and its adjacent tissues by single-cell mRNA sequencing (scRNA-seq), TCR sequencing (TCR-seq) and in vitro neoantigen stimulation. Compared to bystander T cells circulating among tissues, Tas cells were characterized by tumor enrichment, tumor-specific clonal expansion and neoantigen specificity. We found that CXCL13 is a unique marker for both CD4+ and CD8+ Tas cells. Importantly, TCR-T cells expressing TCRs from Tas cells showed significant therapeutic effects on autologous patient-derived xenograft (PDX) tumors. Intratumoral Tas cell levels measured by CXCL13 expression precisely predicted the response to immune checkpoint blockade, indicating a critical role of Tas cells in the antitumor immunity. We further identified CD200 and ENTPD1 as surface markers for CD4+ and CD8+ Tas cells respectively, which enabled the isolation of Tas cells from tumor by Fluorescence Activating Cell Sorter (FACS) sorting. Overall, our results suggest that TCR-T cells engineered with Tas TCRs are a promising agent for personalized immunotherapy, and intratumoral Tas cell levels determine the response to immunotherapy.

A prognostic model for melanoma patients on the basis of immune-related lncRNAs.

The prognosis of melanoma patients is highly variable due to multiple factors conditioning immune response and driving metastatic progression. In this study, we have correlated the expression of immune-related lncRNAs with patient survival, developed a prognostic model, and investigated the characteristics of immune response in the diverse groups. The gene expression profiles and prognostic information of 470 melanoma patients were downloaded from TCGA database. Significantly predictive lncRNAs were identified by multivariate Cox regression analyses, and a prognostic model based on these variables was constructed to predict survival. Kaplan-Meier curves were plotted to estimate overall survival. The predictive accuracy of the model was evaluated by the area under the ROC curve (AUC). Principal component analysis was used to observe the distribution of immune-related genes. CIBERSORT and ESTIMATE were used to evaluate the composition of immune cells and the immune microenvironment. Eight immune-related lncRNAs were determined to be prognostic by multivariate COX regression analysis. The patient scores were calculated and divided into high- and low-risk groups. The model could effectively predict the prognosis in patients of different stages. The AUC of the model is 0.784, which was significantly higher than that of the other variables. There were significant differences in the distribution of immune-related genes between two groups; the immune score and immune function enrichment score were higher in the low risk group.