First-line pembrolizumab therapy in a cisplatin-ineligible patient with plasmacytoid urothelial carcinoma: A case report

Pathological complete response of plasmacytoid variant bladder cancer to pembrolizumab following genomic analysis

Introduction

Plasmacytoid variant bladder cancer is a rare variant of urothelial carcinoma that accounts for 1% of bladder cancers. Plasmacytoid variant urothelial carcinoma is characterized by an aggressive phenotype and poor clinical outcomes.

Case presentation

A 61‐year‐old woman presented with gross hematuria. Cystoscopy showed a 16‐mm solid tumor. Transurethral resection of the bladder tumor was performed, and the pathological diagnosis was invasive plasmacytoid variant urothelial carcinoma. Although the pathological T stage was pT1, computed tomography showed right obturator lymph node swelling. Since previous reports indicate poor response to chemotherapy for this disease, clinical sequencing was performed. Based on the high tumor mutation burden revealed, pembrolizumab was administered for 4 cycles, and computed tomography showed a partial response. Robot‐assisted radical cystectomy was performed, and a pathological complete response including the pelvic lymph node was observed.

Conclusion

Pembrolizumab may be a treatment option for plasmacytoid variant urothelial carcinoma following genomic analysis.

Complete response to anti-PD-L1 antibody in a metastatic bladder cancer associated with novel MSH4 mutation and microsatellite instability

Background

Microsatellite instability (MSI) occurs in 3% of urothelial carcinomas as a result of germline or somatic loss of function mutation in mismatch repair (MMR) proteins.1 Although MSH4 is a member of the DNA MMR mutS family, the association of MSH4 mutation with MSI has not been described. We report a complete responder to PD-L1 blockade who had MSH4 mutated metastatic bladder cancer with mixed histology and MSI. The genomics of urothelial, plasmacytoid and squamous histology was characterized individually through microdissection.

Case presentation

An 81-year-old man was diagnosed with metastatic urothelial carcinoma 8 months after a cystectomy for muscle invasive bladder cancer. His disease was primary refractory to first-line platinum-based chemotherapy but attained complete response to second-line atezolizumab. PCR-based assay revealed MSI high. The tumor mutational burden was elevated to 36.7 mut/Mb. However, immunohistochemistry of MLH1, MSH2, MSH6 and PMS2 was intact. Whole exome sequencing confirmed that the above mentioned four classic MMR genes were wild type but revealed a deleterious MSH4 L359I mutation with variant allele fraction of 30% and Polyphen2 score of 0.873. The association of MSH4 alterations and MSI-H was independently verified in two publicly available MSI-H colorectal cancer datasets.

Conclusions

The novel MSH4 L359I mutation is associated with MSI and high mutational burden leading to remarkable response to PD-L1 blockade. More studies are warranted to establish the causality relationship between MSH4 and MSI.

Progressive plasmacytoid variant bladder cancer with retroperitoneal dissemination: An autopsy case report

INTRODUCTION

Plasmacytoid urothelial carcinoma is a rare and aggressive variant of bladder cancer.

CASE PRESENTATION

A 75-year-old woman presented with plasmacytoid urothelial carcinoma with retroperitoneal dissemination was treated with chemotherapy. After an unsuccessful first-line chemotherapy with gemcitabine and cisplatin, we assessed circulating tumor cells; one such cell was found to be positive for programmed death-ligand 1. The patient received second-line chemotherapy with pembrolizumab. However, the tumor extended to the retroperitoneal organs, and the patient eventually died. Autopsy revealed a widespread diffuse scirrhous infiltration of the carcinoma into the retroperitoneum. However, distant metastasis was not observed.

CONCLUSION

The evaluation of circulating tumor cells and autopsy revealed a disease state of progressive plasmacytoid urothelial carcinoma treated with pembrolizumab.

Metastatic Plasmacytoid Bladder Cancer Harboring a CDH-1 Mutation and Producing High Levels of CA 19-9. A Case Report and Literature Review

Patient: Female, 64-year-old

Final Diagnosis: Plasmacytoid urothelial carcinoma of the bladder

Symptoms: Nausea • vomiting

Medication:—

Clinical Procedure: Cystoscopy

Specialty: Oncology

Atezolizumab in patients with renal insufficiency and mixed variant histology: analyses from an expanded access program in platinum-treated locally advanced or metastatic urothelial carcinoma

Background

Atezolizumab is a treatment for locally advanced/metastatic urothelial carcinoma (mUC). However, its use in patients with renal insufficiency or UC with mixed variant histology (MVH) is not well characterized.

Objective

To report efficacy and safety of atezolizumab in these special subpopulations from an expanded access program (EAP).

Design, setting, and participants

A total of 218 patients were enrolled at 36 US study sites (November 2015–August 2016), and the trial ended following the approval of atezolizumab by the US Food and Drug Administration. This post hoc analysis investigated outcomes in specific study subgroups.

Intervention

Atezolizumab 1200 mg was administered intravenously every 3 weeks until loss of clinical benefit, unacceptable toxicity, death, consent withdrawal, decision to discontinue, commercial availability, or study closure.

Outcome measurements and statistical analysis

Response Evaluation Criteria in Solid Tumors V.1.1 responses and safety were evaluated by baseline renal function and histology.

Results and limitations

Objective responses occurred in 0/6 (0%), 4/19 (21%), 1/27 (3.7%), and 12/62 (19%) of evaluable patients with creatinine clearance (CrCl) <30, 30–45, 45–60, and ≥60 mL/min, respectively, and stable disease was seen in three patients with CrCl <30 mL/min. Objective responses were seen in 13/102 patients (13%) with urothelial carcinoma (UC) histology only and in 4/12 patients (33%) with UC with MVH. Treatment-related adverse event frequencies ranged from 35% to 54% across the earlier indicated CrCl subgroups and they were also similar in patients with pure UC or UC with MVH (46%).

Conclusions

In this EAP mUC subgroup analysis, clinical benefit of atezolizumab occurred in patients with compromised renal function or MVH UC tumors. Safety was comparable across subgroups.

Patient summary

We examined the efficacy and safety of atezolizumab for UC in certain patients participating in an EAP. We found that responses to atezolizumab occurred, and safety was similar, in most patient subgroups with varying levels of kidney functioning or less common types of tumor tissue histology.

Histological Subtypes and Response to PD-1/PD-L1 Blockade in Advanced Urothelial Cancer: A Retrospective Study

PURPOSE

Urinary tract cancer can be pure urothelial carcinoma, pure nonurothelial carcinoma or variant urothelial carcinoma (defined here as mixed urothelial carcinoma). Little is known regarding outcomes for patients with variant urothelial carcinoma receiving immune checkpoint inhibitors. We hypothesized that variant urothelial carcinoma does not compromise immune checkpoint inhibitor efficacy in patients with advanced urothelial carcinoma.

MATERIALS AND METHODS

We performed a retrospective cohort study across 18 institutions. Demographic, clinicopathological, treatment and outcomes data were collected for patients with advanced urothelial carcinoma who received immune checkpoint inhibitors. Patients were divided into pure vs variant urothelial carcinoma subgroups, with variant urothelial carcinoma further divided by type of variant (ie squamous, neuroendocrine etc). We compared overall response rate using univariate and multivariate logistic regression and progression-free survival and overall survival using Kaplan-Meier and univariate and multivariate Cox proportional hazards.

RESULTS

Overall 519 patients were identified, with 395, 406 and 403 included in overall response rate, overall survival and progression-free survival analyses, respectively. Overall response rate to immune checkpoint inhibitors between patients with pure vs variant urothelial carcinoma was comparable (28% vs 29%, p=0.90) without significant differences for individual subtypes vs pure urothelial carcinoma. Median overall survival for patients with pure urothelial carcinoma was 11.0 months vs 10.1 months for variant urothelial carcinoma (p=0.60), but only 4.6 months for patients with neuroendocrine features (9 patients, HR 2.75, 95% CI 1.40-5.40 vs pure urothelial carcinoma, p=0.003). Median progression-free survival was 4.1 months for pure vs 5.2 months for variant urothelial carcinoma (p=0.43) and 3.7 months for neuroendocrine features (HR 1.87, 95% CI 0.92-3.79 vs pure urothelial carcinoma, p=0.09).

CONCLUSIONS

Overall response rate to immune checkpoint inhibitors was comparable across histological types. However, overall survival was worse for patients with tumors containing neuroendocrine features. Variant urothelial carcinoma should not exclude patients from receiving immune checkpoint inhibitors.