Re-challenging chemotherapy after pembrolizumab in platinum-refractory urothelial carcinoma

Durable Response to Enfortumab Vedotin Compared to Re-challenging Chemotherapy in Metastatic Urothelial Carcinoma After Checkpoint Inhibitors

BACKGROUND

Enfortumab vedotin (EV), an antibody-drug conjugate targeting Nectin-4, has been used for patients with metastatic urothelial carcinoma (mUC) after progressing on checkpoint inhibitors (CPIs). Re-challenging chemotherapy with platinum agents and continuing CPIs beyond progressive disease (PD) have often been chosen following PD on CPIs, and several studies indicate favorable treatment effects of re-challenging chemotherapy. There is little evidence for comparing EV and re-challenging chemotherapy in real-world clinical practice.

OBJECTIVE

The aim was to reveal the real-world treatment outcomes of EV, re-challenging chemotherapy, and continuing CPIs beyond PD in mUC patients.

PATIENTS AND METHODS

A multi-institutional dataset of 350 mUC patients treated with CPIs was utilized. Overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and duration of response (DOR) were evaluated to compare the treatment arms.

RESULTS

One hundred and nine mUC patients were treated with EV with a median follow-up of 6.4 months. The ORR and disease control rate (DCR) were 48% and 70%, respectively. The OS from PD on pembrolizumab exhibited significant differences among the three groups, with a median OS of 8, 14, and 29 months in continuing pembrolizumab beyond PD, re-challenging chemotherapy, and EV, respectively. When comparing the survival outcomes from the initiation of the treatment, there is neither a difference in OS (p = 0.124), PFS (p = 0.936), nor ORR (p = 0.816) between EV and re-challenging chemotherapy. Notably, the DOR in patients who achieved an objective response was significantly longer in the EV group than the re-challenging chemotherapy group (a median of 11 and 5 months, p = 0.049). For OS, the difference was not statistically significant (27 and 11 months in EV and re-challenging chemotherapy, respectively: p = 0.05).

CONCLUSIONS

A superior effect of EV on patient survival compared to re-challenging chemotherapy and continuing pembrolizumab beyond PD was observed in our real-world analysis, which is attributed to the durable DOR in EV treatment despite the similar ORR to re-challenging chemotherapy.

Latest evidence on clinical outcomes and prognostic factors of advanced urothelial carcinoma in the era of immune checkpoint inhibitors: a narrative review

The management of advanced (locally advanced or metastatic) urothelial carcinoma has been revolutionized since pembrolizumab was introduced in 2017. Several prognostic factors for advanced urothelial carcinoma treated with pembrolizumab have been reported, including conventional parameters such as performance status and visceral (especially liver) metastasis, laboratory markers such as the neutrophil-to-lymphocyte ratio, sarcopenia, histological/genomic markers such as programmed cell death ligand 1 immunohistochemistry and tumor mutational burden, variant histology, immune-related adverse events, concomitant medications in relation to the gut microbiome, primary tumor site (bladder cancer versus upper tract urothelial carcinoma) and history/combination of radiotherapy. The survival time of advanced urothelial carcinoma has been significantly prolonged (or 'doubled' from 1 to 2 years) after the advent of pembrolizumab, which will be further improved with novel agents such as avelumab and enfortumab vedotin. This review summarizes the latest evidence on clinical outcomes and prognostic factors of advanced urothelial carcinoma in the contemporary era of immune checkpoint inhibitors.

Enfortumab vedotin versus platinum rechallenge in post-platinum, post-pembrolizumab advanced urothelial carcinoma: A multicenter propensity score-matched study

OBJECTIVE

Enfortumab vedotin (EV) was approved for advanced urothelial carcinoma (UC) in 2021 after the EV-301 trial showed its superiority to non-platinum-based chemotherapy as later-line treatment after platinum-based chemotherapy and immune checkpoint inhibitors including pembrolizumab. However, no study has compared EV with rechallenging platinum-based chemotherapy (i.e., "platinum rechallenge") in that setting.

METHODS

In total, 283 patients received pembrolizumab for advanced UC after platinum-based chemotherapy between 2018 and 2023. Of them, 41 and 25 patients received EV and platinum rechallenge, respectively, as later-line treatment after pembrolizumab. After excluding two patients with EV without imaging evaluation, we compared oncological outcomes, including progression-free survival (PFS) and overall survival (OS), between the EV (n = 39) and platinum rechallenge groups (n = 25) using propensity score matching (PSM).

RESULTS

Analyses on crude data (n = 64) showed no significant differences between the two groups regarding patients' baseline characteristics. PFS (5 months) and OS (11 months) in the EV group were comparable to those (8 and 12 months, respectively) in the platinum rechallenge group. After PSM (n = 36), the baseline characteristics between the two groups became more balanced, and PFS (not reached) and OS (not reached) in the EV group were comparable to those (8 and 11 months, respectively) in the platinum rechallenge group.

CONCLUSIONS

EV and platinum rechallenge showed equivalent oncological outcomes, even after PSM, and both treatments should therefore be effective treatment options for post-platinum, post-pembrolizumab advanced UC.

Tertiary lymphoid structure and neutrophil-lymphocyte ratio coordinately predict outcome of pembrolizumab

Emerging evidence suggests that the presence of tertiary lymphoid structures (TLS) and neutrophil-lymphocyte ratio (NLR) in peripheral blood is associated with the treatment response to checkpoint inhibitors (CPIs), whereas there is limited knowledge regarding whether these factors reciprocally impact the treatment outcomes of CPIs in metastatic urothelial carcinoma (mUC). Herein, we investigated treatment outcomes of platinum-refractory mUC patients (50 cases with whole-exome and transcriptome sequencing) treated with pembrolizumab. The pathological review identified 24% of cases of TLS in the specimens. There was no significant difference in the NLR between the TLS- and TLS+ groups (p = 0.153). In the lower NLR group, both overall survival and progression-free survival were significantly longer in patients with TLS than in those without TLS, whereas the favorable outcomes associated with TLS were not observed in patients in the higher NLR group. We explored transcriptomic differences in UC with TLS. The TLS was comparably observed between luminal (20%) and basal (25%) tumor subtypes (p = 0.736). Exploring putative immune-checkpoint genes revealed that ICOSLG (B7-H2) was significantly increased in tumors with lower NLR. KRT expression levels exhibited higher basal cell markers (KRT5 and KRT17) in the higher NLR group and lower differentiated cell markers (KRT8 and KRT18) in patients with TLS. In conclusion, the improved outcomes of pembrolizumab treatment in mUC are restricted to patients with lower NLR. Our findings begin to elucidate a distinct molecular pattern for the presence of TLS according to the NLR in peripheral blood.

Concurrent palliative radiation with pembrolizumab for platinum-refractory urothelial carcinoma is associated with improved overall survival

Background and Purpose

Pembrolizumab has now become a standard of care in metastatic urothelial carcinoma (mUC), although the treatment effect of the drug substantially differs among individuals. Emerging evidence suggests that radiotherapy exerts a synergistic effect with PD-1 blockade. We sought to elucidate the survival outcomes in patients who underwent palliative radiation with the pembrolizumab treatment.

Methods

We retrospectively investigated our multi-institutional dataset of 235 platinum-refractory mUC patients treated with pembrolizumab as second-line treatment, collected from January 2018 and October 2021. Propensity score matching was performed to reduce biases by potential confounding factors for overall survival (OS).

Results

With a median follow-up of 6.8 months, the median OS from the initiation of pembrolizumab was 13 months in 235 patients. Palliative radiation was performed in 71 (30.2%) patients for whom the median radiation dose and fraction were 30 Gy and 10 fractions, respectively. Irradiated sites were bone in 24 (33.8%), lymph node in 17 (23.9%), lung in 3 (4.2%), brain in 8 (11.3%), and other sites in 19 (26.8%). OS from the initiation of pembrolizumab was significantly longer in patients who underwent concurrent palliative radiation with pembrolizumab (39 patients: median OS: 21 months) than in both patients with palliative radiation before pembrolizumab (32 patients: median OS: 9 months) (p = 0.001) and those without palliative radiation throughout the follow-up (164 patients: median OS: 13 months) (p = 0.019). After the propensity-score matching by putative confounding factors, longer OS in patients treated with concurrent palliative radiation with pembrolizumab (n = 36) was still observed compared to patients without the concurrent palliative radiation (n = 36) in the pair matched cohort (median OS of 29 and 13 months, respectively, p = 0.033).

Conclusions

Our findings suggest that the concurrent administration of palliative radiation with pembrolizumab offers a favorable effect on OS in platinum-refractory mUC patients.