Comparison of efficacy and toxicity of second-line combination chemotherapy regimens in patients with advanced urothelial carcinoma

Targeted Inhibition of O-Linked β-N-Acetylglucosamine Transferase as a Promising Therapeutic Strategy to Restore Chemosensitivity and Attenuate Aggressive Tumor Traits in Chemoresistant Urothelial Carcinoma of the Bladder

Acquisition of acquired chemoresistance during treatment cycles in urothelial carcinoma of the bladder (UCB) is the major cause of death through enhancing the risk of cancer progression and metastasis. Elevated glucose flux through the abnormal upregulation of O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (OGT) controls key signaling and metabolic pathways regulating diverse cancer cell phenotypes. This study showed that OGT expression levels in two human UCB cell models with acquired resistance to gemcitabine and paclitaxel were significantly upregulated compared with those in parental cells. Reducing hyper-O-GlcNAcylation by OGT knockdown (KD) markedly facilitated chemosensitivity to the corresponding chemotherapeutics in both cells, and combination treatment with OGT-KD showed more severe growth defects in chemoresistant sublines. We subsequently verified the suppressive effects of OGT-KD monotherapy on cell migration/invasion in vitro and xenograft tumor growth in vivo in chemoresistant UCB cells. Transcriptome analysis of these cells revealed 97 upregulated genes, which were enriched in multiple oncogenic pathways. Our final choice of suspected OGT glycosylation substrate was VCAN, S1PR3, PDGFRB, and PRKCG, the knockdown of which induced cell growth defects. These findings demonstrate the vital role of dysregulated OGT activity and hyper-O-GlcNAcylation in modulating treatment failure and tumor aggression in chemoresistant UCB.

Impact of the objective response to and number of cycles of platinum-based first-line chemotherapy for metastatic urothelial carcinoma on overall survival of patients treated with pembrolizumab

OBJECTIVES

To investigate the impact of the number of cycles and objective response to chemotherapy on overall survival in patients with metastatic urothelial carcinoma treated with pembrolizumab.

METHODS

This multicenter, retrospective study included 755 patients from 59 institutions with advanced, chemoresistant urothelial carcinoma who received pembrolizumab. The associations of the overall survival with the number of cycles and best objective response were investigated using Cox multiple regression analysis.

RESULTS

Overall, 391 patients received standard first-line chemotherapy and pembrolizumab as a second-line treatment, and were included in the final analysis. Of the 391 patients, 185 received less than four cycles, 134 received four to six cycles and 72 received more than six cycles of first-line chemotherapy. An objective response (complete or partial response) to chemotherapy was observed in 145 patients (37.1%). Univariate analysis showed that the overall survival of patients who received more than six cycles or responded to chemotherapy (complete or partial response) was significantly longer than that of patients who received less than four cycles or did not respond to chemotherapy (stable or progressive disease). At multivariate levels, no correlations were observed between overall survival and the number of cycles of or the response to chemotherapy.

CONCLUSIONS

Therapeutic benefit of pembrolizumab can be expected irrespective of the objective response to and number of cycles of platinum-based first-line chemotherapy.

Pembrolizumab Versus Combined Chemotherapy With Gemcitabine and Paclitaxel: A Comparative Assessment of Clinical Outcomes in Patients With Platinum-refractory Advanced Urothelial Cancer

BACKGROUND/AIM

There are limited data on comprehensive assessments of several treatments as second-line therapy against advanced urothelial cancer (UC). The objective of this study was to compare clinical outcomes between advanced UC patients receiving either pembrolizumab (Pem) or combined chemotherapy with gemcitabine and paclitaxel (GP) as second-line therapy.

PATIENTS AND METHODS

This study retrospectively analyzed the clinical outcomes of 89 patients with platinum-refractory advanced UC, consisting of 46 and 43 who received Pem and GP therapy, respectively, as second-line treatment.

RESULTS

There were no significant differences in major clinicopathological parameters between Pem and GP groups. No significant difference in the objective response rate was noted between the two groups. Progression-free survival (PFS) in the Pem group was significantly longer than that in the GP group; however, there was no significant difference in overall survival (OS) between them. Multivariate analyses identified performance status ≤2 and liver metastasis as independent factors associated with poor outcomes in both PFS and OS. The incidence of adverse events in the GP group was significantly higher than that in the Pem group.

CONCLUSION

Pem could be regarded as standard agent for platinum-refractory advanced UC patients.

Myeloid-derived suppressor cells are essential partners for immune checkpoint inhibitors in the treatment of cisplatin-resistant bladder cancer

Myeloid-derived suppressor cells (MDSCs) are one of the key players that contribute to immune evasion. The purpose of the present study was to investigate whether MDSCs could be a novel target for the treatment of cisplatin-resistant bladder cancer. We established cisplatin-resistant bladder cancer cell lines (MB49R, MBT-2R, and T24R) and evaluated chemokine expression and MDSC expansion. We also assessed the antitumor effect by depleting MDSCs with or without a α-PD-L1 antibody using MB49R xenograft models. The chemokine expression of CXCL1, CXCL2, and CCL2 increased in cisplatin-resistant cells compared to those in their parent strains. Monocytic MDSCs (Mo-MDSCs) were observed more frequently compared to polymorphonuclear MDSCs (PMN-MDSCs) in MB49R tumors. The immunosuppressive genes arginase 1 and iNOS were comparably expressed in each MDSC subtype. In vivo, combination therapy targeting both PMN- and Mo-MDSCs using α-Gr1 and α-Ly6C antibodies significantly reduced tumor volume with increased infiltration of CD8 T cells in the tumor. Finally, co-targeting pan-MDSCs and PD-L1 remarkably reduced the tumor growth. These findings suggest that targeting MDSCs might enhance the therapeutic effect of immune checkpoint inhibitors in cisplatin-resistant bladder cancers.

Pembrolizumab versus chemotherapy in recurrent, advanced urothelial cancer in Japanese patients: a subgroup analysis of the phase 3 KEYNOTE-045 trial

Background

The open-label, randomized, active-controlled KEYNOTE-045 study (NCT02256436) showed that second-line pembrolizumab significantly improved overall survival (OS) of patients with advanced/metastatic urothelial cancer (UC) that progressed after first-line platinum-containing chemotherapy, compared with standard chemotherapy (paclitaxel, docetaxel, or vinflunine). Pembrolizumab is approved for patients with bladder cancer in Japan.

Patients and methods

Analysis was performed in the subgroup of Japanese patients enrolled in the KEYNOTE-045 study. Coprimary end points were OS and progression-free survival (PFS). Objective response rate (ORR) and safety were secondary end points.

Results

Fifty-two Japanese patients (pembrolizumab, n = 30; chemotherapy, n = 22) were followed up for a median of 26.1 months. Patients who received pembrolizumab compared with chemotherapy had a 19% lower risk for death (hazard ratio [HR] 0.81, 95% CI 0.44–1.50); after adjusting for baseline covariates, the HR for OS was 0.61 (95% CI 0.32–1.15). The 24-month OS rate was higher with pembrolizumab (26.9% vs 14.3%). PFS was 2.0 and 4.9 months for pembrolizumab and chemotherapy, respectively (HR 1.71, 95% CI 0.95–3.08). ORR was similar for pembrolizumab and chemotherapy (20.0% vs 18.2%); durability of response was higher with pembrolizumab: 67% and 33% of patients, respectively, maintained a response for > 12 months. Treatment-related adverse events, including grade 3–5 events, occurred less frequently with pembrolizumab.

Conclusions

Pembrolizumab provided durable antitumor activity in patients with locally advanced/metastatic UC that progressed after platinum-containing chemotherapy in the overall population and in the Japanese subgroup; safety profile was consistent with that previously observed for pembrolizumab.

Electronic supplementary material

The online version of this article (10.1007/s10147-019-01545-4) contains supplementary material, which is available to authorized users.