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

Difference of oncological efficacy between two immune checkpoint inhibitors following first-line platinum-based chemotherapy in patients with unresectable, metastatic, advanced urothelial carcinoma: a multicenter real-world Japanese cohort

BACKGROUND

Maintenance avelumab is currently recommended for patients with unresectable and/or metastatic (mUC) achieving at least stable disease (SD) on first-line platinum-based chemotherapy (1L-CT). Pembrolizumab is an alternative therapeutic avenue for this patient cohort in clinical practice. We investigated real-world data, focusing on the correlation between response to 1L-CT and oncological efficacy of subsequent immune checkpoint inhibitor (ICI) therapy with avelumab or pembrolizumab.

METHODS

A multicenter database registered 626 patients with mUC diagnosed from 2008-2023; among these, 175 receiving 2-6 cycles of 1L-CT followed by ICI therapy. Patients were categorized based on response to 1L-CT using the Response Evaluation Criteria in Solid Tumors (v1.1). Objective response rate on ICI, progression to ICI-free survival (ICI-PFS), and overall survival from start of 1L-CT were compared between avelumab-treated and pembrolizumab-treated patients in each response subgroup.

RESULTS

ICI-PFS was significantly longer in patients achieving partial response on 1L-CT and subsequently receiving pembrolizumab compared to those receiving avelumab. Notably, patients achieving SD on 1L-CT and subsequently receiving pembrolizumab manifested significantly higher objective response rate (14% and 41%, respectively) and prolonged ICI-PFS relative to those receiving avelumab. In contrast, overall survival did not delineate difference between patients treated with avelumab versus pembrolizumab. Similar findings were discerned in the subanalysis of patients having favorable SD (tumor shrinkage, from - 29 to 0%) and unfavorable SD (tumor enlargement, from + 1 to + 19%) on 1L-CT.

CONCLUSIONS

Our study provides real-world evidence regarding difference of oncological efficacy between maintenance avelumab and subsequent pembrolizumab in patients with mUC who achieved partial response or SD on 1L-CT.

A Multicenter, Single-Arm, Prospective Trial to Evaluate Efficacy and Safety of Dose-Dense Methotrexate, Vinblastine, Doxorubicin, and Carboplatin (DD-MVACarbo) Chemotherapy for Cisplatin-Ineligible Patients with Advanced Urothelial Cancer: Study Protocol of the CARBUNCLE Trial

Unresectable, metastatic, advanced urothelial carcinoma (aUC) is an aggressive disease and is treated with platinum-containing first-line chemotherapy, followed by immune checkpoint inhibitors and antibody-drug conjugates. Response to first-line chemotherapy is a vital priority in sequential treatment strategies because a better response to first-line chemotherapy is associated with a better response to subsequent therapies. Gemcitabine plus carboplatin chemotherapy is conventionally recommended for cisplatin-ineligible patients. This multicenter, single-arm prospective trial will investigate whether dose-dense methotrexate, vinblastine, doxorubicin, and carboplatin (DD-MVACarbo) chemotherapy is superior to gemcitabine plus carboplatin chemotherapy in terms of efficacy in platinum-naïve, cisplatin-ineligible patients with aUC. After screening and registration, a total of 46 patients will be treated with this novel chemotherapy regimen. The primary endpoint is the objective response rate. The secondary endpoints include disease control rate, patient-reported outcomes, and adverse events. No evidence of this novel intervention is available as of July 2024. The results are expected to change the standard of care and improve the management of patients with aUC.

Trend in overall survival from the start of first-line chemotherapy in patients with metastatic urothelial carcinoma

New approaches involving immune checkpoint inhibitors and antibody-drug conjugates prolong overall survival in patients with metastatic urothelial carcinoma. However, the access to such systemic therapy in clinical practice is suboptimal, and whether these agents improve overall survival in patients with metastatic urothelial carcinoma over time remains unclear. Hence, we investigated the overall survival trend from the initiation of first-line therapy with these agents to identify changes due to the medication and time of treatment initiation. We retrospectively evaluated 195 patients from a single center. They were treated with chemotherapy, pembrolizumab, or avelumab or enfortumab vedotin. The treatment was categorized into chemotherapy, pembrolizumab or avelumab/enfortumab vedotin period. The new agents prolonged overall survival from the start of first-line therapy. Furthermore, sequential treatment with these agents in real-world clinical practice has been reported to prolong overall survival. These study results will have major implications when a new first-line therapy is approved in the future.

Three versus four cycles of neoadjuvant chemotherapy for muscle-invasive bladder cancer: a systematic review and meta-analysis

OBJECTIVE

The optimal cycle of neoadjuvant chemotherapy (NAC) for muscle-invasive bladder cancer (MIBC) remains controversial. This study aimed to compare the efficacy of three and four cycles of NAC in the treatment of MIBC through a systematic review and meta-analysis of the literature.

MATERIALS AND METHODS

Relevant studies were systematically collected and reviewed in PubMed, Medline, Embase, Web of Science Databases, and the Cochrane Library. Relative ratios (RRs), Hazard ratios (HRs) and their 95% confidence intervals (CIs) were used to estimate outcome measures. Studies comparing the pathological response and prognosis of three versus four cycles of NAC for MIBC were included.

RESULTS

Five studies were included in this meta-analysis, including 2190 patients, of whom 1016 underwent three cycles of NAC and 1174 underwent four cycles of NAC. All studies were retrospective cohort studies. We found that 4 cycles of NAC had significantly better cancer-specific survival than 3 cycles (HR = 1.31, 95%CI,1.03-1.67, p = 0.029). There was no significant difference in overall survival between patients who received 3 and 4 cycles of chemotherapy (HR = 1.18, 95%CI = 0.83-1.69, p = 0.345). Similarly, no significant difference was observed in pathological objective response (RR = 0.95, 95%CI= 0.81-1.11, p = 0.515) and complete response rates (RR = 0.87, 95%CI = 0.69-1.11, p = 0.256) in MIBC after 3 or 4 cycles of NAC.

CONCLUSIONS

Three and four cycles of NAC had similar pathological responses and prognosis for MIBC, although the cancer-specific survival rate of four cycles was better than that of three cycles.

Treatment impact of newly approved therapeutic agents for metastatic urothelial carcinoma in Japan: a single-center retrospective study

Although recent clinical trials of new therapeutic agents for metastatic urothelial carcinoma have shown prolonged overall survival, there are few real-world evidence. To assess the impact of new therapeutic agents, we performed retrospective analysis for consecutive 158 metastatic urothelial carcinoma patients who performed systemic therapy in our institution between May 2008 and August 2023. We defined a period from May 2008 to December 2017, when pembrolizumab was first introduced to the clinical setting in the new therapeutic agents for metastatic urothelial carcinoma in Japan, as "pre new drug era" and a period from January 2018 to August 2023 as "post new drug era". We compared overall survival between pre- and post- new drug era using Kaplan-Meier method with log rank test. Median overall survival of pre- and post- new drug era were 14.5 months (95% confidence intervals: 11.6-16.7) and 23.1 months (95% confidence intervals: 14.5-NA), respectively (p < 0.001). Five-year survival rate of pre- and post- new drug era was 7.0% (95% confidence intervals: 2.3-15.3) and 36.3% (95% confidence intervals: 21.4-51.5), respectively. Multivariable Cox proportional hazards regression analysis of factors associated with overall survival showed that enfortumab vedotin administration, administration of second-line or more systemic therapy, best overall response of SD, PR and CR in first-line systemic therapy, higher serum albumin and lower CRP were factors for overall survival prolongation. Introduction of new therapeutic agents for metastatic urothelial carcinoma contributed to the improvement of overall survival in comparison with the era without these agents.

Significance of second progression-free survival in patients with advanced urothelial cancer who received platinum-based combination chemotherapy followed by pembrolizumab

OBJECTIVES

The present study comprehensively investigated the significance of several factors reflecting the therapeutic effects of anticancer treatment on overall survival (OS) in advanced urothelial cancer (UC) patients receiving sequential systemic therapy.

METHODS

This study included 101 consecutive advanced UC patients who received first-line platinum-based combination chemotherapy followed by second-line pembrolizumab. The impacts of the following factors on OS in these patients were analyzed: responses to chemotherapy, responses to pembrolizumab, progression-free survival (PFS) with chemotherapy, PFS with pembrolizumab, and second PFS (PFS2).

RESULTS

The median age of patients was 71 years, and 35 and 66 had UC in the upper urinary tract and bladder, respectively. objective response rate to first-line chemotherapy and second-line pembrolizumab were 37.6% and 19.8%, respectively. Median PFS with chemotherapy, pembrolizumab, and PFS2 were 5, 4, and 9 months, respectively. Uni- and multivariate analyses of the five factors examined identified PFS with pembrolizumab and PFS2 as independent surrogates for OS, with PFS2 (hazard ratio [HR] = 0.23) being more closely associated with OS than PFS with pembrolizumab (HR = 0.31). Furthermore, uni- and multivariate analyses of various prognostic parameters showed the independent impacts of baseline performance status (PS) and neutrophil-to-lymphocyte ratio (NLR) on PFS2.

CONCLUSIONS

The present results suggest the potential of PFS2 as an optimal surrogate for OS in advanced UC patients receiving standard sequential systemic therapy and indicate that intensive treatment needs to be considered for those with poor PS and/or high NLR prior to the introduction of first-line chemotherapy.

Real-world outcomes of pembrolizumab for platinum-refractory advanced urothelial carcinoma: Efficacy, safety, and evidence for trial-unfit patients

Pembrolizumab, monoclonal antibody targeting programmed cell death 1, is widely used for platinum-refractory urothelial carcinoma (UC) patients. Although the survival benefit of pembrolizumab was proven in the well-designed phase III trial, these data represent only a part of patients due to strictly defined eligibility criteria. The patients' characteristics in the clinical practice are much more heterogenous than those of trial participants. The real-world experience is useful to validate the trial result and find suitable candidates for the treatment. Similarly, real-world data plays a significant role in addressing the efficacy and safety of special populations, such as poor performance status or older patients. This review summarizes the real-world evidence on pembrolizumab for platinum-refractory UCs and discusses the clinical risk factors and efficacy for trial-ineligible patients.

Switch-maintenance avelumab immunotherapy following first-line chemotherapy for patients with advanced, unresectable or metastatic urothelial carcinoma: the first Japanese real-world evidence from a multicenter study

OBJECTIVE

To develop the first Japanese real-world evidence of switch-maintenance avelumab in advanced, unresectable or metastatic urothelial carcinoma (aUC).

METHODS

A multicenter-derived database registered 505 patients diagnosed with aUC between 2008 and 2021. Of these, 204 patients (40%) were selected and stratified according to the type of therapy used: maintenance avelumab group (27 [5.3%]), second-line (2 L) pembrolizumab group (103 [20%]) and 2 L cytotoxic chemotherapy group (74 [15%]). The progression-free survival and overall survival from the initiation of following therapy were compared. Tumor response was evaluated based on the Response Evaluation Criteria in Solid Tumors guideline v1.1 during the treatment period. A detailed analysis was performed in the maintenance avelumab group to investigate possible factors associated with response to avelumab therapy.

RESULTS

The maintenance avelumab group had a longer overall survival, not progression-free survival, compared with the other two treatment groups. The median treatment-free interval between the last dose of first-line (1 L) chemotherapy and the initiation of avelumab therapy was 6 weeks (range, 3-22). Disease control rate of maintenance avelumab therapy in patients with a treatment-free interval of ≤6 weeks was higher than that in patients with a treatment-free interval of >6 weeks (77 vs 40%, P = 0.029). The patients showing objective response to 1 L chemotherapy were less likely to experience tumor relapse (4 of 19) after the initiation of avelumab therapy compared with those showing stable disease (7 of 8).

CONCLUSIONS

Objective response to 1 L chemotherapy and early induction of maintenance avelumab therapy may be associated with increased benefit from maintenance avelumab therapy.

Probiotics enhances anti-tumor immune response induced by gemcitabine plus cisplatin chemotherapy for urothelial cancer

Chemotherapy drugs, such as gemcitabine and cisplatin (GC), are frequently administered to patients with advanced urothelial carcinoma, however the influence of the gut microbiota on their action is unclear. Thus, we investigated the effects of GC on the gut microbiome and determined whether oral supplementation with a probiotics mixture of Lactobacillus casei Shirota and Bifidobacterium breve enhanced the anti-tumor immune response. After subcutaneous inoculation with MBT2 murine bladder cancer cells, syngenic C3H mice were randomly allocated into eight groups. The gut microbiome cluster pattern was altered in both the GC and oral probiotics groups (p = 0.025). Both tumor-bearing conditions (no treatment) and GC chemotherapy influenced Pseudoclostridium, Robinsoniella, Merdimonas, and Phocea in the gut. Furthermore, comparison of the GC-treated and GC + probiotics groups revealed an association of four methyltransferase family enzymes and two short-change fatty acid-related enzymes with oral probiotics use. A significant difference in tumor volume was observed between the GC and GC + probiotics groups at week 2 of treatment. Additionally, decreased recruitment of cancer-associated fibroblasts and regulatory T cells, and activation of CD8⁺ T cells and dendritic cells were observed in the tumor microenvironment. Our findings reveal the positive effects of a probiotics mixture of Lactobacillus and Bifidobacterium in enhancing anti-tumor effects through the gut-tumor immune response axis. Future clinical trials are needed to evaluate the full benefits of this novel supplement with oral probiotics in patients with advanced urothelial carcinoma.

Limited predictive impact of tumor size dynamics on further tumor shrinkage after 4 cycles of first-line chemotherapy in patients with advanced urothelial carcinoma

PURPOSE

To investigate the correlation between tumor size changes during the initial 4 cycles of first-line chemotherapy and tumor shrinkage following 2 additional cycles of chemotherapy in patients with advanced urothelial carcinoma (aUC) who experienced disease control after initial chemotherapy.

METHODS

We retrospectively reviewed 128 patients with aUC who received first-line chemotherapy. We analyzed 51 patients with disease control (stable disease or better) at the end of the fourth cycle. Of these, 47 patients received 1 to 2 additional cycles of chemotherapy, whereas the remaining patients underwent observation. For patients who received additional chemotherapy, the change in tumor size after additional chemotherapy (cycles 5-6) was defined as "no shrinkage" (tumor growth), "minor shrinkage" (no tumor growth or ≤10% reduction in tumor size), or "shrinkage" (>10% reduction in tumor size). Then, we investigated the relationship between the rate of tumor size change during the initial 4 cycles and that after additional chemotherapy.

RESULTS

Of the patients who received additional chemotherapy, the change in tumor size was categorized as no shrinkage in 21 patients (44.7%), minor shrinkage in 18 patients (38.3%), and shrinkage in 8 patients (17%). Regarding predictors of tumor shrinkage after additional chemotherapy, the rate of tumor size change between the cycles 3 and 4 (area under the receiver operating characteristics curve = 0.642) was correlated with the trend of the tumor shrinkage (P = 0.009) and the likelihood of beneficial tumor shrinkage after additional chemotherapy (minor shrinkage + shrinkage; P = 0.02). However, the change in tumor size between cycles 1 and 2, cycles 1 and 4, or cycles 3 and 4 was not satisfactorily predictive of further tumor shrinkage because of substantial overlaps of the tumor size changes.

CONCLUSIONS

Only a small subset of patients would have substantial tumor shrinkage by additional cycles after successful induction of 4 cycle chemotherapy. Tumor size dynamics during the initial 4 cycles of chemotherapy displayed limited ability to predict the subset of patients with further tumor shrinkage after additional chemotherapy. Therefore, it might be better to consider switch maintenance immunotherapy for patients who experience disease control after the fourth cycle of first-line chemotherapy.

Are there differences in the characteristics of patients who respond to gemcitabine plus cisplatin chemotherapy and those who respond to pembrolizumab therapy for metastatic urothelial carcinoma? Multicenter retrospective study

OBJECTIVES

To evaluate factors to predict overall survival of metastatic urothelial carcinoma patients treated with gemcitabine plus cisplatin chemotherapy or pembrolizumab therapy.

METHODS

We retrospectively evaluated two metastatic urothelial carcinoma cohorts treated with (i) gemcitabine plus cisplatin or (ii) pembrolizumab. The gemcitabine plus cisplatin cohort was treated from December 2005 through December 2014 while the pembrolizumab cohort was treated from January 2018 through December 2020. Using multivariate analyses, we evaluated the risk factors for overall survival in each cohort and compared them. None of the gemcitabine plus cisplatin cohort patients were treated with pembrolizumab. All patients in the pembrolizumab cohort were treated with prior platinum-based chemotherapy.

RESULTS

There were 184 patients in the gemcitabine plus cisplatin cohort and 91 in the pembrolizumab cohort. The mean follow-up periods were 714 and 284 days, respectively. In multivariate analysis, the risk factors for overall survival in the gemcitabine plus cisplatin cohort were liver metastasis, worse Eastern Cooperative Oncology Group performance status (1 or more), no primary site resection, and a high prognostic index (1 or more). In the pembrolizumab cohort, liver metastasis, bone metastasis, and worse Eastern Cooperative Oncology Group-performance status (1 or more), and high prognostic index (1 or more) were the risk factors for overall survival. In the pembrolizumab cohort, patients with a complete response or partial response during prior platinum-based chemotherapy had better overall survival with the following pembrolizumab treatment than those with stable or progressive disease (P = 0.004).

CONCLUSIONS

Considering the similarity of these risk factors in two sequential treatments, it may be possible to predict the response to pembrolizumab according to the response to prior chemotherapy.

Effect of active anticancer therapy on serologic response to SARS-CoV-2 BNT162b2 vaccine in patients with urothelial and renal cell carcinoma

Objectives

To evaluate the serologic response to the BNT162b2 messenger ribonucleic acid vaccine in patients with urothelial carcinoma and renal cell carcinoma.

Methods

Between June 2021 and November 2021, we retrospectively evaluated blood samples from 60 healthy controls (control group), 57 patients with urothelial carcinoma, and 28 patients with renal cell carcinoma who had received two doses of the BNT162b2 vaccine at Hirosaki University Hospital. We determined the immunoglobulin G antibody titers against the severe acute respiratory syndrome coronavirus 2 spike receptor‐binding domain. Seropositivity was defined as ≥15 U/mL. We investigate factors associated with antibody titers and seropositivity in the patients with urothelial carcinoma and renal cell carcinoma.

Results

Antibody titers in the control, urothelial carcinoma, and renal cell carcinoma groups were 813, 431, and 500 U/mL, respectively. Seropositivity was 100%, 90%, and 96% in the control, urothelial carcinoma, and renal cell carcinoma groups, respectively. Of the 85 patients, 37 of 57 (65%) and 21 of 28 (75%) were actively undergoing anticancer treatment for urothelial carcinoma and renal cell carcinoma, respectively. Anti‐severe acute respiratory syndrome coronavirus 2 spike immunoglobulin G antibody titers and seropositivity was not significantly different between the patients with urothelial carcinoma and renal cell carcinoma. Anti‐severe acute respiratory syndrome coronavirus 2 spike immunoglobulin G antibody titers were not significantly associated with active anticancer therapy or steroid treatment for immune‐related adverse events. Univariable logistic regression analysis revealed that older age and metastatic disease were significantly and negatively associated with seropositivity.

Conclusions

Patients with urothelial carcinoma or renal cell carcinoma exhibited an adequate antibody response to the BNT162b2 vaccine. Active anticancer therapy was not significantly associated with seropositivity following vaccination with severe acute respiratory syndrome coronavirus 2 BNT162b2 in patients with urothelial carcinoma and renal cell carcinoma.

Clinical practice pattern in patients with advanced urothelial cancer who had progressed on pembrolizumab in the pre-enfortumab vedotin era

OBJECTIVES

Pembrolizumab, an anti-PD-1 monoclonal antibody, revolutionized the treatment for advanced urothelial carcinoma. However, the standard treatment for patients after disease progression with pembrolizumab had not been established until the recent approval of enfortumab vedotin. We analyzed the treatment of these patients in the real world, and the patient background and outcomes.

METHODS

We extracted data from 543 patients who experienced progressive disease after pembrolizumab initiation from a Japanese nation-wide cohort of platinum-refractory, metastatic urothelial carcinoma.

RESULTS

The median overall survival of the 543 patients was 3.5 months (95% confidence interval 3.0-4.1). Of these, only 20.6% (n = 112) received chemotherapy as a subsequent systemic treatment after progressive disease. The regimen of chemotherapy was very diverse. The median overall survival was 11.9 months (95% confidence interval 9.2-14.7) for patients who received chemotherapy, compared to 2.4 months for those who did not receive chemotherapy (95% confidence interval 2.1-2.9; P < 0.0001). Patients who received subsequent chemotherapy were more likely to have better performance status, neutrophil-to-lymphocyte ratio <3, hemoglobin >11 mg/dL, and history of a single chemotherapeutic regimen at pembrolizumab initiation.

CONCLUSIONS

This report highlights the real-world practice of the management after pembrolizumab treatment failure in the pre-enfortumab vedotin era, characterized by infrequent use of subsequent anticancer therapy comprising various regimens, reflecting the lack of a standard treatment. Clinical introduction of enfortumab vedotin is expected to improve treatment outcomes in this setting. The present study will provide important baseline data for evaluating the influence of enfortumab vedotin on clinical practices and outcomes.

Significant Improvement of Prognosis After the Advent of Immune Checkpoint Inhibitors in Patients with Advanced, Unresectable, or Metastatic Urothelial Carcinoma: A Propensity Score Matching and Inverse Probability of Treatment Weighting Analysis on Real-World Data

Purpose

The treatment landscape for advanced, unresectable, or metastatic urothelial carcinoma (aUC) has shifted substantially since the advent of immune checkpoint inhibitors (ICIs). We investigated the extent to which pembrolizumab therapy is superior to conventional chemotherapy as a second-line treatment.

Patients and Methods

A multicenter-derived database registered 454 patients diagnosed with aUC between 2008 and 2020. Of these, 94 patients (21%) who received second-line pembrolizumab and 75 (17%) who received second-line chemotherapy but never received third-line or later ICI therapy were included. We compared overall survival (OS) from the initial date of first-line chemotherapy between two groups by adjusting for prognostic factors through propensity score matching (PSM) and inverse probability of treatment weighting (IPTW). The IPTW-adjusted hazard ratio and 95% confidence interval were estimated using a multivariate Cox regression analysis. To identify patients who were more likely to benefit from second-line pembrolizumab than from chemotherapy, we performed a subgroup analysis for OS with an IPTW-adjusted model.

Results

The PSM-adjusted comparison showed a significant improvement in the prognosis with second-line pembrolizumab use (P = 0.01). The OS benefit with the advent of pembrolizumab was 8 months (18 months vs 26 months). Multivariable analyses using IPTW adjustment demonstrated that lymph node metastasis (P = 0.001), lung metastasis (P = 0.013), and bone metastasis (P = 0.003) were poor independent prognostic factors, and pembrolizumab use (P = 0.021) was a favorable independent prognostic factor. Subgroup analyses revealed that pembrolizumab was associated with survival benefits over chemotherapy in all subgroups, including young patients (age <70 years), those who received radical surgery, and those without visceral metastasis.

Conclusion

We demonstrated a significant improvement in prognosis after the advent of pembrolizumab for patients with aUC. ICIs should not be restricted based on patient characteristics.

Management of bladder cancer in older patients

Evidence has shown that patients with bladder cancer are diagnosed at a much older age compared with those with other cancers. Given that co-morbidities and frailty are prevalent in older patients with advanced bladder cancer, they are easily excluded from randomized controlled trials. As little evidence has been available regarding assessment tools for frailty, the management of those patients remains challenging. This weakness is strongly manifested in muscle-invasive bladder cancer. Despite radical cystectomy is the standard of care for bladder cancer, there is an extensive undertreatment of older adult patients with potentially curative muscle-invasive bladder cancer. However, it is also true that radical cystectomy is often unsuitable for vulnerable or frail patients. Bladder preservation using trimodality therapy has been utilized as an alternative option, but the appropriate selection criteria for trimodality therapy remain unclear. Cisplatin-based regimens have been the first choice for advanced disease among eligible patients. Moreover, immunotherapy appears to have similar benefits and tolerability in both older and younger patients. Furthermore, palliative or supportive interventions need to be initiated earlier in patients with metastatic disease. Accumulating evidence suggests that frailty may play a key role in the selection of treatment modalities. Older patients should be considered for standard treatment based on frailty and not chronological age. Moreover, older patients with bladder cancer need to undergo geriatric assessment for proper decision-making.

A retrospective study on optimal number of cycles of the first-line platinum-based chemotherapy for metastatic urothelial carcinoma

BACKGROUND

Recently, switch maintenance with avelumab has been approved for the treatment of advanced or metastatic urothelial carcinoma (UC), with no progression after four to six cycles of first-line platinum-based chemotherapy. However, the optimal number of cycles of platinum-based chemotherapy has not been determined.

OBJECTIVE

To analyze the clinical characteristics of patients with advanced UC who were treated with platinum-based chemotherapy and investigate the association between the number of cycles of the treatment and the patients' overall survival.

METHODS

A total of 124 patients with advanced UC who were treated with first-line platinum-based chemotherapy at Osaka City University Hospital between April 2009 and January 2020 were retrospectively reviewed.

RESULTS

Of the 124 patients, clinical information regarding overall survival was available for 115 patients. The median age was 72 years (range, 43-95 years). Only 59 patients (51.3 %) were treated with gemcitabine and cisplatin, and 52 patients (45.2 %) were treated with gemcitabine and carboplatin. The median number of cycles was three (1-8), and the percentage of patients who discontinued chemotherapy due to progressive disease was 80.3%, 64.0%, and 86.4% in those receiving one to three, four, and five or more cycles, respectively. Moreover, no difference in overall survival was observed between patients who received four cycles and those who received five or more cycles at both univariate and multivariate levels.

CONCLUSIONS

The present study shows that five or more cycles of first-line platinum-based chemotherapy did not prolong overall survival compared with four cycles, suggesting that four cycles of chemotherapy might be sufficient, considering the new treatment strategy involving switch maintenance with avelumab.

Response to Pembrolizumab After Dose-Reduced Cisplatin Plus Gemcitabine Chemotherapy Is Inferior to That After Carboplatin Plus Gemcitabine Chemotherapy in Cisplatin-Unfit Patients With Advanced Urothelial Carcinoma

INTRODUCTION

Response to pembrolizumab after first-line chemotherapy is vital to prolonged survival in advanced, unresectable, and/or metastatic urothelial carcinoma (aUC). However, there are sparse clinical data on host-tumor immune modification by first-line platinum-based chemotherapy. This study investigated the association between response to first-line gemcitabine plus cisplatin (GC) or carboplatin (GCarbo) chemotherapy and response to subsequent pembrolizumab treatment.

PATIENTS AND METHODS

A multicenter-derived database registered 454 patients diagnosed with aUC between 2008 and 2020. Of these, 108 patients who received first-line GC or GCarbo followed by second-line or later pembrolizumab were eligible for investigation and were classified into 3 groups: 48 receiving full-dose GC, 21 receiving dose-reduced GC, and 39 receiving GCarbo. Overall survival (OS) was calculated using the Kaplan-Meier method and compared using the log-rank test. Possible factors associated with the response to pembrolizumab were evaluated using binary logistic regression methods.

RESULTS

The rate of patients undergoing surgical removal of the primary organ was higher and creatinine clearance was lower in the dose-reduced GC and GCarbo groups than in the full-dose GC groups. Pembrolizumab responders had significantly better survival benefits than nonresponders. The rate of pembrolizumab responders was much higher in first-line chemotherapy responders than in first-line chemotherapy nonresponders. In contrast to the full-dose GC and GCarbo groups, the pembrolizumab responder rate was lower, and no association was observed between response to first-line chemotherapy and response to pembrolizumab in the dose-reduced GC group.

CONCLUSION

Cisplatin and carboplatin may play an important role in the antitumor immune response, which could impact the outcome of subsequent pembrolizumab treatment. Given that the rate of response to pembrolizumab after dose-reduced GC chemotherapy was relatively low, this regimen is not recommended for cis-unfit patients with aUC. Further studies are required to understand the mechanisms responsible for the cross-reactivity of platinum and immune checkpoint inhibitors.