Imatinib demonstrated significant activity in patients with metastatic melanoma harboring genetic c-Kit aberrations, with an overall response rate of 23.3%. Escalation to 800 mg/d could not restore disease control.

The accumulation of myeloid-derived suppressor cells (MDSCs) has been observed in solid tumors and is correlated with tumor progression; however, the underlying mechanism is still poorly understood. In this study, we identified a mechanism by which tumor cells induce MDSC accumulation and expansion in the bladder cancer (BC) microenvironment via CXCL2/MIF-CXCR2 signaling. Elevated expression of CXCL2 and MIF and an increased number of CD33 MDSCs were detected in BC tissues, and these increases were significantly associated with advanced disease stage and poor patient prognosis (P<0.01). A positive association was observed between CXCL2 or MIF expression and the number of tumor-infiltrating CD33 MDSCs (P<0.01). Subsequently, we demonstrated that CD45CD33CD11bHLA-DR MDSCs from fresh BC tissues displayed high levels of suppressive molecules, including Arg1, iNOS, ROS, PDL-1 and P-STAT3, and stronger suppression of T-cell proliferation. Interestingly, these CD45CD33CD11bHLA-DR MDSCs exhibited increased CXCR2 expression compared with that in peripheral blood from BC patients or healthy controls (P<0.05). Chemotaxis assay revealed that bladder cancer cell line J82 induced MDSC migration via CXCL2/MIF-CXCR2 signaling in vitro. Mechanistic studies demonstrated that J82-induced MDSC trafficking and CXCR2 expression were associated with increased phosphorylation of p38, ERK and p65. Conversely, inhibition of the phosphorylation of p38, ERK or p65 decreased J82-induced MDSC trafficking and CXCR2 expression. CXCL2/MIF-stimulated activation of the mitogen-activated protein kinase and nuclear factor kappa B pathways in MDSCs was MyD88 dependent. Overall, our results identify the CXCL2/MIF-CXCR2 axis as an important mediator in MDSC recruitment and as predictors and potential therapeutic targets in BC patients.

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BackgroundHepatitis B virus (HBV) reactivation is a serious complication in patients with cancers and HBV infection undergoing immunosuppressant treatment or chemotherapy. However, the safety of anti-programmed cell death (PD) -1 and anti-programmed cell death-ligand 1 (PD-L1) therapy in these patients is unknown because they were excluded from clinical trials of immunotherapy.MethodsThis retrospective cohort study involved consecutive hepatitis B surface antigen (HBsAg) -positive cancer patients who were referred to Sun Yat-sen University Cancer Center and received an anti-PD-1/PD-L1 antibody between January 1, 2015 and July 31, 2018. The primary end point was the rate of the occurrence of HBV reactivation.ResultsIn total, 114 eligible patients were included, among whom 90 (79%) were male, and the median (range) age was 46 (16–76) years. Six patients (5.3%) developed HBV reactivation, occurring at a median of 18 weeks (range, 3–35 weeks) from the commencement of immunotherapy. Among these patients, all of them had undetectable baseline HBV DNA; one had prophylactic antiviral therapy while five did not; four were positive for Hepatitis B e antigen while the other two were negative. At reactivation, the median HBV DNA level was 3.89 × 104 IU/mL (range, 1.80 × 103–6.00 × 107 IU/mL); five had HBV-related hepatitis and one exhibited increasing HBV DNA level without alanine transaminase elevation. No HBV-related fatal events occurred. The lack of antiviral prophylaxis was the only significant risk factor for HBV reactivation (odds ratio, 17.50 [95% CI, 1.95–157.07], P = .004).ConclusionsHBV reactivation occurs in a subset of HBsAg-positive cancer patients undergoing anti-PD-1 or anti-PD-L1 immunotherapy. Regular monitoring of HBV DNA and antiviral prophylaxis are advised to prevent this potentially fatal complication.

Our study showed safety and efficacy of PD-1 blockade in advanced melanoma patients in China with predominantly acral and mucosal subtypes. This is the largest prospective research focusing on differential clinical responses and unique mutation signatures among melanoma subtypes in China based on the whole-exome sequencing and RNA-sequencing profiling. we found CDK4 or CCND1(Cyclin D1) amplifications occurred more often in acral and mucosal melanoma than in non-acral cutaneous melanoma. CCND1 copy number variation as a part of 11q13 genomic amplification, occurred exclusively in acral and mucosal subtypes and correlated with poor response to PD-1 blockade treatment, suggesting a potential CDK4/6 targeting therapy or combination strategy of CDK4/6 inhibitor with anti-PD-1 for CCND1 amplified melanomas. Our results showed that for acral and mucosal subtypes in particular, combination treatment strategies are likely needed to further improve the clinical outcome of PD-1 blockade.Research.

Background Pembrolizumab shows robust antitumor activity and favorable safety in metastatic melanoma. KEYNOTE-151 evaluated pembrolizumab in Chinese patients, who have more aggressive melanoma subtypes than other populations. Methods Chinese patients aged ≥18 years with advanced melanoma previously treated with one line of therapy received pembrolizumab 2 mg/kg every 3 weeks for 35 cycles or until confirmed disease progression, intolerable toxicity, or study withdrawal. Primary end points were objective response rate (ORR) per RECIST v1.1 by blinded independent central review and safety. Key secondary end points included duration of response (DOR) and progression-free survival (PFS) per RECIST v1.1 and overall survival (OS). Results Median age was 52 years (N = 103); 37.9% had acral and 14.6% had mucosal melanoma. Median follow-up was 7.9 months at data cutoff (December 27, 2017). ORR was 16.7% (95% CI, 10.0–25.3%) (1 complete, 16 partial responses). Disease control rate was 38.2%. ORR was 15.8% for acral, 13.3% for mucosal melanoma. Median DOR was 8.4 months; 65.6% of patients had response duration ≥6 months. Median PFS was 2.8 months (95% CI, 2.7–3.5 months); 6-month rate was 20.4%. Median OS was 12.1 months (95% CI, 9.6 months–not reached); 6-month rate, 75.7%; 12-month rate, 50.6%. Treatment-related AEs (TRAEs) occurred in 87 (84.5%) patients; 9 (8.7%) experienced grade 3/4 TRAE and 2 (1.9%) discontinued because of TRAE; none died. Two deaths occurred that were unrelated to treatment. Conclusions Pembrolizumab was well tolerated and provided clinically meaningful antitumor activity as second-line therapy in Chinese patients with advanced melanoma.

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