Second-line therapy for disseminated small-cell lung cancer: optimal management remains to be defined

Overcoming resistance in small-cell lung cancer

INTRODUCTION

Small-cell lung cancer (SCLC) accounts for 15% of lung cancers and has a dismal prognosis due to early dissemination and acquired chemoresistance. The initial good response to chemotherapy is followed by refractory relapses within 1-2 years. Mechanisms leading to chemoresistance are not clear and progress is poor.

AREAS COVERED

This article reviews the current evidence of the resistance of SCLCs at the cellular level including alteration of key proteins and the possible presence of cancer stem cells (CSCs). Without compelling evidence for cellular mechanisms and clinical failures of novel approaches, the study of SCLC has advanced to the role of 3D tumor cell aggregates in chemoresistance.

EXPERT OPINION

The scarcity of viable tumor specimen from relapsed SCLC patients has hampered the investigations of acquired chemoresistance but a panel of nine SCLC circulating tumor cell (CTC) cell lines have revealed characteristics of SCLC in the advanced refractory states. The chemoresistance of relapsed SCLC seems to be linked to the spontaneous formation of large spheroids, termed tumorospheres, which contain resistant quiescent and hypoxic cells shielded by a physical barrier. So far, drugs to tackle large tumor spheroids are in preclinical and early clinical development.

Phase II study of nab-paclitaxel with gemcitabine for relapsed/refractory small cell lung cancer

Background

Patients with small cell lung cancer (SCLC) often respond to first-line chemoimmunotherapy. However, relapse is inevitable and is associated with a poor prognosis. Treatments for relapsed SCLC, such as lurbinectedin and topotecan, are limited by modest efficacy and significant hematologic adverse events, leaving a need for newer therapeutic agents or regimens. The combination of gemcitabine and nab-paclitaxel is active and safe in other types of malignancies, such as pancreatic cancer.

Patients and methods

We conducted a phase II trial evaluating the efficacy and safety of gemcitabine and nab-paclitaxel in patients with relapsed/refractory SCLC. The primary endpoint was objective response rate (ORR), defined as the proportion of patients with confirmed complete or partial response. Secondary endpoints included time to progression (TTP), progression-free survival (PFS), overall survival (OS), and safety.

Results

Between October 2016 and May 2021, 32 patients were enrolled. Patients were followed for a median of 9.3 months (range 1.8-65.2). Median age was 65 years (range 48-81). Fifty percent of patients were female. Fifty-three percent of patients had platinum-resistant/refractory relapsed SCLC. The ORR was 28.1% (95% confidence interval [CI] 15.5-100%). Median PFS was 2.9 months (95% CI 2.4-3.6), and median OS was 9.3 months (95% CI 5.2-12.4). Seven patients (21.9%) developed grade 3 or 4 neutropenia.

Conclusion

Our study showed that the combination of gemcitabine and nab-paclitaxel led to encouraging outcomes in relapsed/refractory SCLC. Further studies are needed to compare this combination with other treatments used for relapsed SCLC, including lurbinectedin, temozolomide, and topotecan.

Clinical trial registration

https://clinicaltrials.gov/study/NCT02769832?cond=NCT02769832&rank=1, identifier NCT02769832.

Molecular mechanisms underlying the regulation of tumour suppressor genes in lung cancer

Tumour suppressor genes play a cardinal role in the development of a large array of human cancers, including lung cancer, which is one of the most frequently diagnosed cancers worldwide. Therefore, extensive studies have been committed to deciphering the underlying mechanisms of alterations of tumour suppressor genes in governing tumourigenesis, as well as resistance to cancer therapies. In spite of the encouraging clinical outcomes demonstrated by lung cancer patients on initial treatment, the subsequent unresponsiveness to first-line treatments manifested by virtually all the patients is inherently a contentious issue. In light of the aforementioned concerns, this review compiles the current knowledge on the molecular mechanisms of some of the tumour suppressor genes implicated in lung cancer that are either frequently mutated and/or are located on the chromosomal arms having high LOH rates (1p, 3p, 9p, 10q, 13q, and 17p). Our study identifies specific genomic loci prone to LOH, revealing a recurrent pattern in lung cancer cases. These loci, including 3p14.2 (FHIT), 9p21.3 (p16INK4a), 10q23 (PTEN), 17p13 (TP53), exhibit a higher susceptibility to LOH due to environmental factors such as exposure to DNA-damaging agents (carcinogens in cigarette smoke) and genetic factors such as chromosomal instability, genetic mutations, DNA replication errors, and genetic predisposition. Furthermore, this review summarizes the current treatment landscape and advancements for lung cancers, including the challenges and endeavours to overcome it. This review envisages inspired researchers to embark on a journey of discovery to add to the list of what was known in hopes of prompting the development of effective therapeutic strategies for lung cancer.

Olaparib and durvalumab in patients with relapsed small cell lung cancer (MEDIOLA): An open-label, multicenter, phase 1/2, basket study

INTRODUCTION

Preclinical studies have demonstrated increased efficacy with combined DNA damage response inhibition and immune checkpoint blockade compared with either alone. We assessed olaparib in combination with durvalumab in patients with relapsed small cell lung cancer (SCLC).

METHODS

Patients with previously treated limited or extensive-stage SCLC received oral olaparib 300 mg twice daily, as run-in for 4 weeks, then with durvalumab (1500 mg intravenously every 4 weeks) until disease progression. Primary endpoints were safety, tolerability, and 12-week disease control rate (DCR). Secondary endpoints included 28-week DCR, objective response rate (ORR), duration of response, progression-free survival, overall survival, change in tumor size, and programmed death-ligand 1 (PD-L1) expression subgroup analyses.

RESULTS

Forty patients were enrolled and analyzed for safety; 38 were analyzed for efficacy. Eleven patients (28.9% [90% confidence interval (CI), 17.2-43.3]) had disease control at 12 weeks. ORR was 10.5% (95% CI, 2.9-24.8). Median progression-free and overall survival were 2.4 (95% CI, 0.9-3.0)months and 7.6(95% CI, 5.6-8.8)months, respectively. The most common adverse events (≥40.0%) were anemia, nausea, and fatigue. Grade ≥ 3 adverse events occurred in 32 patients (80.0%). PD-L1 levels, tumor mutational burden, and other genetic mutations were evaluated, but no significant correlations with clinical outcomes wereobserved.

CONCLUSIONS

Tolerability of olaparib with durvalumab was consistent with the safety profile of each agent alone. Although the 12-week DCR did not meet the prespecified target (60%), four patients responded, and median overall survival was promising for a pretreated SCLC population. Further analyses are required to identify patients most likely to benefit from this treatment approach.

Therapeutic Modalities in Small Cell Lung Cancer: a paradigm shift after decades of quiescence

INTRODUCTION

Small cell lung cancer (SCLC) is known to be the most aggressive of all thoracic malignancies, notoriously known for its very poor prognosis. Platinum based chemotherapy has been the standard of care for decades. Despite years of research, no treatment novelties with significant impact on survival have been achieved until recently. The last few years have witnessed light at the end of the tunnel with immunotherapy proving to improve survival. Nevertheless, responses were not homogeneous in all subgroups, and finding who would best benefit from treatment remains unanswered. Multiple limitations exist, and the quest for optimal biomarkers seemed unfruitful until the discovery of different SCLC phenotypes.

AREAS COVERED

In this review, the authors briefly discuss SCLC phenotypes and biomarker assays. Then, the authors continue with the main trials of SCLC treatment using chemotherapy, immunotherapy and targeted treatment in the front-line or subsequent line settings.

EXPERT OPINION

Research has been extensively implemented to better understand the biology of SCLC, and test for the optimal use of immunotherapy in patients with SCLC, as well as to enhance responses via possible combinations. Targeted mechanisms of action have also been attempted; yet no solid proof of efficacy has been established.

Immunotherapy-Related Cystitis: Case Report and Review of the Literature

Immune checkpoint inhibitors (ICIs) including anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA4) and anti-programmed death cell protein 1 (anti-PD1) have extended patient survival benefit and revolutionized cancer treatment. As ICIs rely on immune regeneration to eliminate tumor cells, they can also lead to an imbalance of immune reactions often called immune-related adverse events (irAEs). Rare irAEs such as ocular or cardiac toxicity or vasculitis are seen in less than 1% of patients receiving ICIs. Immune-related cystitis remains a rare occurrence. Herein, we describe a patient with extensive-stage small cell lung cancer (SCLC) and a history of syphilis with a complete response to second-line treatment using nivolumab plus paclitaxel who complained of urinary irritation symptoms. At biopsy, we found infiltration of CD3⁺ and CD8⁺ lymphocytes in the urothelium. Although there are reports describing immune-related cystitis in cancer patients, our case has comprehensive pathological confirmation and a differentiation diagnosis. In this report, we review other cases to elucidate clinical characteristics and discuss suitable management of this rare irAE.