Pembrolizumab Plus Amrubicin in Patients With Relapsed SCLC: Multi-Institutional, Single-Arm Phase 2 Study

Tissue and circulating biomarkers of benefit to immunotherapy in extensive-stage small cell lung cancer patients

Extensive stage-Small-Cell Lung Cancer (ES-SCLC) is an aggressive cancer with dismal prognosis. The addition of immune-checkpoint inhibitors (ICIs) to platinum-based chemotherapy have been consistently demonstrated to improve outcomes and survival, becoming the new standard in first - line treatment of ES-SCLC patients. However, despite positive results reported in the pivotal trials, longer benefit appears evident only for a selected group of patients. Several predictive biomarkers have been studied so far but the prospective identification of patients more likely to experience better outcome seems to be challenging in SCLC. Indeed, classical immune predictive biomarkers as PD-L1 and tumor mutational burden (TMB) seem not to correlate with outcomes. Recently, a new molecular classification of SCLC based on differential expression of genes associated with specific clinical behaviors and therapeutic vulnerability have been presented suggesting a new field to be investigated. Despite the achievements, these studies focused mainly on inter-tumoral heterogeneity, limiting the exploration of intra-tumoral heterogeneity and cell to cell interactions. New analysis methods are ongoing in order to explore subtypes plasticity. Analysis on single biopsies cannot catch the whole genomic profile and dynamic change of disease over time and during treatment. Moreover, the availability of tissue for translational research is limited due to the low proportion of patients undergoing surgery. In this context, liquid biopsy is a promising tool to detect reliable predictive biomarkers. Here, we reviewed the current available data on predictive role of tissue and liquid biomarkers in ES-SCLC patients receiving ICIs. We assessed latest results in terms of predictive and prognostic value of gene expression profiling in SCLC. Finally, we explored the role of liquid biopsy as a tool to monitor SCLC patients over time.

Preconditioning with immunogenic cell death-inducing treatments for subsequent immunotherapy

Since the dawn of anticancer immunotherapy, the clinical use of immune checkpoint inhibitors (ICI) has increased exponentially. Monoclonal antibodies targeting CTLA-4 and the PD-1/PD-L1 interaction were first introduced for the treatment of patients with unresectable melanoma. In melanoma, ICI lead to durable regression in a significant number of patients and have thus been clinically approved as a first-line treatment of advanced disease. Over the past years an increasing number of regulatory approvals have been granted for the use of ICI in patients affected by a large range of distinct carcinomas. In retrospect surprisingly, it has been discovered that particularly successful chemotherapeutic treatments are able to trigger anticancer immune responses because they induce immunogenic cell death (ICD), hence killing cancer cells in a way that they elicit an immune response against tumor-associated antigens. Logically, preclinical studies as well as clinical trials are currently exploring the possibility to combine ICD inducers with ICI to obtain optimal therapeutic effects. Here, we provide a broad overview of current strategies for the implementation of combinatorial approaches involving ICD induction followed by ICI in anticancer therapy.

From targeted therapy to a novel way: Immunogenic cell death in lung cancer

Lung cancer (LC) is one of the most incident malignancies and a leading cause of cancer mortality worldwide. Common tumorigenic drivers of LC mainly include genetic alterations of EGFR, ALK, KRAS, BRAF, ROS1, and MET. Small inhibitory molecules and antibodies selectively targeting these alterations or/and their downstream signaling pathways have been approved for treatment of LC. Unfortunately, following initial positive responses to these targeted therapies, a large number of patients show dismal prognosis due to the occurrence of resistance mechanisms, such as novel mutations of these genes and activation of alternative signaling pathways. Over the past decade, it has become clear that there is no possible cure for LC unless potent antitumor immune responses are induced by therapeutic intervention. Immunogenic cell death (ICD) is a newly emerged concept, a form of regulated cell death that is sufficient to activate adaptive immune responses against tumor cells. It transforms dying cancer cells into a therapeutic vaccine and stimulates long-lasting protective antitumor immunity. In this review, we discuss the key targetable genetic aberrations and the underlying mechanism of ICD in LC. Various agents inducing ICD are summarized and the possibility of harnessing ICD in LC immunotherapy is further explored.

Efficacy and Safety of Amrubicin in Small Cell Carcinoma Previously Treated with Immune Checkpoint Inhibitors and Chemotherapy

Simple Summary

Therapeutic efficacy of chemotherapy combined with immune checkpoint inhibitors as first-line therapy has been previously demonstrated in extensive-stage small cell lung cancer. However, there are no reports of any cytotoxic drug that is effective as second-line therapy in extensive-stage small cell lung cancer patients previously treated with chemotherapy and immune checkpoint inhibitors as a first-line treatment. In the present study, we retrospectively evaluated patients with extensive-stage small cell lung cancer to clarify whether the previous treatment with chemotherapy and immune checkpoint inhibitors impacts the efficacy and safety of amrubicin as a second-line treatment. This study shows that the efficacy and safety of amrubicin in extensive-stage small cell lung cancer remains unchanged irrespective of previous treatment with chemotherapy and immune checkpoint inhibitors.

Abstract

Adding an immune checkpoint inhibitor to chemotherapy to treat extensive-stage small cell lung cancer is effective. However, there are no reports of an effective second-line treatment in patients previously treated with chemotherapy and immune checkpoint inhibitors as a first-line treatment. Here, we assessed the efficacy and safety of amrubicin as a second-line treatment for extensive-stage small cell lung cancer after chemotherapy and immune checkpoint inhibitor combination therapy. The study enrolled 150 patients with extensive-stage small cell lung cancer. The efficacy and the incidence of adverse events were compared between patients previously treated with immune checkpoint inhibitors and patients without previous immune checkpoint inhibitor treatment. One hundred and twenty-three patients were eligible. There was no difference in objective response rate, time-to-treatment failure, progression-free survival, and overall survival between both groups. The incidence of adverse events was similar in both treatment groups. Pretreatment with immune checkpoint inhibitors was not associated with an increase in amrubicin-related adverse events. This study shows that the efficacy of amrubicin in extensive-stage small cell lung cancer remains unchanged irrespective of previous treatment with immune checkpoint inhibitors. Amrubicin-related adverse events did not increase in patients previously treated with immune checkpoint inhibitors.

Phase I study of amrubicin plus cisplatin and concurrent accelerated hyperfractionated thoracic radiotherapy for limited-disease small cell lung cancer: protocol of ACIST study

Background

Etoposide plus cisplatin (EP) combined with concurrent accelerated hyperfractionated thoracic radiotherapy (AHTRT) is the standard treatment strategy for unresectable limited‐disease (LD) small cell lung cancer (SCLC), which has remained unchanged for over two decades. Based on a previous study that confirmed the non‐inferiority of amrubicin (AMR) plus cisplatin (AP) when compared with EP for extensive‐disease (ED) SCLC, we have previously conducted a phase I study assessing AP with concurrent TRT (2 Gy/time, once daily, 50 Gy in total) for LD‐SCLC therapy. Our findings revealed that AP with concurrent TRT could prolong overall survival to 39.5 months with manageable toxicities. Therefore, we plan to conduct a phase I study to investigate and determine the effect of AP combined with AHTRT, recommended dose (RD), maximum tolerated dose (MTD), and dose‐limiting toxicity (DLT) of AP in patients with LD‐SCLC.

Methods

Treatment‐naive patients with LD‐SCLC, age between 20 and 75 years, who had a performance status of 0 or 1 and adequate organ functions will be enrolled. For chemotherapy, cisplatin 60 mg/m²/day (day 1) and AMR (day 1 to 3) will be administered with AHTRT (1.5 Gy/time, twice daily, 45 Gy in total). The initial AMR dose is set to 25 mg/m²/day. RD and MTD will be determined by evaluating toxicities.

Discussion

Based on our previous study, the initial dose of AMR 25 mg/m² is expected to be tolerated and acceptable. Here, we aim to determine whether treatment with AP and concurrent AHTRT would be an optimal choice with manageable toxicities for LD‐SCLC.

Efficacy and safety of amrubicin monotherapy after atezolizumab plus carboplatin and etoposide in patients with relapsed small-cell lung cancer

This study examined the activity and safety of amrubicin monotherapy among relapsed small-cell lung cancer (SCLC) patients who had previously been treated with atezolizumab plus carboplatin and etoposide (AteCE). This retrospective study evaluated patients with relapsed SCLC who were treated with previously AteCE combination therapy followed by amrubicin monotherapy between August 2019 and May 2021. Clinical efficacy and toxicity were analyzed. Overall, 40 patients were included: 12 and 28 patients had sensitive and refractory relapse, respectively. The response rate was 32.5% (25.0% in the sensitive group and 35.7% in the refractory group). The median progression-free survival (PFS) and overall survival (OS) from the first amrubicin treatment was 3.4 months (95% CI: 1.9-4.9 months) and 9.9 months (95% CI: 4.5-11.5 months), respectively. There was no significant between-group difference in median PFS (3.6 months vs. 3.2 months, p = 0.42) or median OS (11.2 months vs. 7.3 months, p = 0.78). Grade ≥ 3 hematological adverse events occurred as follows: decreased white blood cells in 52.5% of patients; decreased neutrophil count in 57.5%; and febrile neutropenia in 10.0%. Grade 3 pneumonitis was observed in one patient. There were no treatment-related deaths. Amrubicin is feasible and effective for relapsed SCLC patients previously treated with AteCE therapy. Although immune checkpoint inhibitor treatment (ICI) does not improve the effect of amrubicin, the toxicity is not increased, suggesting that amrubicin remains effective even after ICI administration. Thus, amrubicin after AteCE could be the preferred standard chemotherapeutic choice in patients with relapsed SCLC.

Small cell lung cancer responds to immunogenic chemotherapy followed by PD-1 blockade

Sequential combination of immunogenic cell death (ICD)-induced interventions with subsequent immunotherapy has shown efficacy in preclinical models and clinical evaluation. Recently, a clinical trial enrolling small cell lung cancer patients treated with amrubicin together with PD-1 blockade confirmed the notion that ICD sensitizes tumors to immune checkpoint inhibitors.

What Are the Biomarkers for Immunotherapy in SCLC?

Small-cell lung cancer (SCLC) is an aggressive malignancy that exhibits a rapid doubling time, a high growth fraction, and the early development of widespread metastases. The addition of immune checkpoint inhibitors to first-line chemotherapy represents the first significant improvement of systemic therapy in several decades. However, in contrast to its effects on non-SCLC, the advantageous effects of immunotherapy addition are modest in SCLC. In particular, only a small number of SCLC patients benefit from immune checkpoint inhibitors. Additionally, biomarkers selection is lacking for SCLC, with clinical trials largely focusing on unselected populations. Here, we review the data concerning the major biomarkers for immunotherapy, namely, programmed death ligand 1 expression and tumour mutational burden. Furthermore, we explore other potential biomarkers, including the role of the immune microenvironment in SCLC, the role of genetic alterations, and the potential links between neurological paraneoplastic syndromes, serum anti-neuronal nuclear antibodies, and outcomes in SCLC patients treated with immunotherapy.