Clinical efficacy of amrubicin in patients with small cell lung cancer relapse after first-line treatment including immune checkpoint inhibitors: A retrospective multicenter study (TOPGAN 2021-01)

Impact of immune-related adverse events on survival outcomes in extensive-stage small cell lung cancer patients treated with immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors have recently become the standard of care in the first-line treatment of extensive-stage small cell lung cancer. Although immune-related adverse events have been reported to influence prognosis in non-small cell lung cancer patients, few studies have investigated the prognostic value of immune-related adverse events in small cell lung cancer patients. In this study, we evaluated the prognosis of patients who developed immune-related adverse events after first-line treatment with immune checkpoint inhibitor-based chemotherapy for extensive-stage small cell lung cancer.

METHODS

We enrolled 90 patients with extensive-stage small cell lung cancer who received immune checkpoint inhibitor-based chemotherapy as first-line treatment from September 2019 to December 2022 in six hospitals in Japan. The patients were categorized into groups with and without immune-related adverse events.

RESULTS

There were 23 patients with and 67 without immune-related adverse events. Seventeen patients had grade 1-2 immune-related adverse events, and nine (including overlapping cases) had grade ≥3. The most frequent immune-related adverse event was a skin rash. The median survival time was 22 months in patients with immune-related adverse events and 9.3 months in patients without immune-related adverse events. The hazard ratio was 0.40 (95% confidence interval: 0.19-0.83, p = 0.013).

CONCLUSIONS

The results of this study show that immune-related adverse events are associated with improved survival outcomes in patients with extensive-stage small cell lung cancer.

Metastatic small cell bladder cancer treated with sequential systemic therapy including pembrolizumab and amrubicin: A case report

Introduction

Small cell bladder cancer is a relatively rare tumor, representing <1% of all bladder tumors. Amrubicin monotherapy is used as second-line treatment for small cell lung cancer in Japan.

Case presentation

A 79-year-old woman presented with gross hematuria and was diagnosed with small cell bladder cancer (T2 or higher). Neoadjuvant chemotherapy with etoposide and cisplatin resulted in a partial response. Robot-assisted radical cystectomy was performed, and radical resection was achieved. As we identified metastasis in the pleura 1 year later, we administered carboplatin and etoposide, which resulted in a partial response. Although pembrolizumab was initiated as maintenance therapy, it was not effective. Amrubicin was given as third-line therapy, and stable disease was achieved without serious adverse effect for 6 months.

Conclusion

Although there is no established treatment for metastatic small cell bladder cancer, the current case report suggests the effectiveness of amrubicin in this setting.

Reconsidering the Cutoff Value for Sensitive and Refractory Relapses in Extensive-Stage SCLC in the Era of Immunotherapy

INTRODUCTION

Traditionally, relapsed SCLC has been classified as "sensitive" or "refractory" on the basis of cutoff values (60 or 90 d) for the duration between the last chemotherapy and disease progression. Nevertheless, these cutoff values are not derived from rigorous analytical methods, and their applicability to contemporary treatments remains uncertain.

METHODS

We conducted a retrospective multicenter study on patients with extensive-stage SCLC who underwent second-line therapy after platinum-doublet chemotherapy with or without immune checkpoint inhibitor (ICI) resistance before (pre-ICI cohort) and after (post-ICI cohort) approval of combination immunotherapy. We selected the optimal platinum-free interval cutoff value with the lowest two-sided p value in the multivariable Cox regression model for second-line overall survival. The internal validity of the chosen cutoff value was assessed using twofold cross-validation.

RESULTS

There were 235 and 98 patients in the pre-ICI and post-ICI cohorts, respectively. In the pre-ICI cohort, the optimal cutoff was 59 days (p = 0.0001); the hazard ratio calculated using twofold cross-validation was 1.31 (95% confidence interval: 0.95-1.82]). In the post-ICI cohort, although the 60- and 90-day cutoff values could predict prognosis (60 d; p = 0.002, 90 d; p = 0.005), the optimal cutoff value was 75 days (p = 0.0002), which resulted in a median second-line overall survival of 15.9 and 5.0 months for patients with sensitive and refractory relapse, respectively (hazard ratio = 2.77, 95% confidence interval: 1.56-4.93).

CONCLUSIONS

We clarified the previously ambiguous cutoff values for classifying relapsed SCLC and revealed that the 75-day cutoff most accurately predicts subsequent prognosis than the traditional cutoffs in the post-ICI era.

Extensive-Stage Small-Cell Lung Cancer: Current Landscape and Future Prospects

Small-cell lung cancer (SCLC) is characterized by aggressive disease progression and tendency to metastasize. Although chemotherapy for extensive-stage SCLC (ES-SCLC) has remained unchanged for decades, immune checkpoint inhibitors have become the primary therapy for ES-SCLC. However, the number of patients benefiting from immunotherapy is limited, and the treatment outcomes remain unsatisfactory. In addition, predictive biomarkers for immunotherapy have not yet been identified. Recent reports have shed light on the genomics of SCLC and defined four distinct molecular subtypes based on transcription factor expression. This may increase our understanding of the biology of SCLC and identify novel therapeutic targets and drugs. In this article, we review the current standard management of ES-SCLC and present the most recent reports to further our understanding of molecular classification, predictive biomarkers, and prospective therapies, including immunotherapy, chemotherapy, and targeted therapy.