Complete Response of Bone Metastasis in Non-small Cell Lung Cancer With Pembrolizumab: Two Case Reports

Combining dynamics of serum inflammatory and nutritional indicators as novel biomarkers in immune checkpoint inhibitor treatment of non-small-cell lung cancer with bone metastases

OBJECTIVES

We aimed to investigate the association of the dynamics of serum inflammatory and nutritional indicators with immune checkpoint inhibitor (ICI) response in non-small-cell lung cancer (NSCLC) with bone metastases, and to develop a novel predictive scoring system based on these indicators.

METHODS

Patients with NSCLC having bone metastases treated with ICIs were categorized as: the development cohort (January 2016 to March 2021, n = 60) and the validation cohort (April 2021 to June 2023, n = 40). Serum indicators of inflammation and nutrition such as C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), albumin, prognostic nutritional index (PNI) were investigated before and six weeks after ICI initiation. The correlations of these dynamics with bone metastasis response rate (BoMRR) and overall survival (OS) were analyzed. A scoring system consisting of independent predictors was developed (IMMUNO-SCORE) and correlations with clinical outcomes were validated using the validation cohort.

RESULTS

In the development cohort, multivariable analysis showed that NLR and PNI dynamics and CRP, NLR, and PNI dynamics were independent predictors of BoMRR and OS, respectively. The IMMUNO-SCORE consisting of NLR and PNI dynamics, which were the common predictors of the clinical outcomes, was significantly correlated with BoMRR (p < 0.01) and OS (p < 0.001) in cross-validation. The area under the curve of the score (0.786) was higher than individual NLR and PNI dynamics (0.72 and 0.684).

CONCLUSION

Dynamics in NLR and PNI were demonstrated as biomarkers of treatment response and prognosis in ICI treatment of NSCLC with bone metastases, and the score combining these biomarkers was significantly correlated with clinical outcomes.

Immunotherapy as a potential treatment approach for currently incurable bone metastasis

Once cancer metastasizes to the bone, the prognosis of cancer patients becomes extremely poor. Unfortunately, the current most successful treatment for bone metastasis can extend their survival by only a few months. Although recent studies have revealed promising impacts of cancer immunotherapies, their treatment efficacy on bone metastatic diseases remains controversial. Therefore, in this review, we discussed (i) preclinical and clinical evidence of the immunotherapeutic strategies for cancer bone metastasis, mainly focusing on cell-based immunotherapy, cytokine-based immunotherapy, and immune checkpoint blockade, and (ii) current shortcomings of immunotherapy for bone metastasis and their potential future directions. Although the evidence on treatment efficacy and safety, as well as long-term effects, is limited, immunotherapies could induce partial or complete remissions in a few cancer patients with bone metastasis. However, there are still hurdles, such as the immunosuppressive nature of the bone marrow microenvironment and poor distribution of cell-based immunotherapies to bone, that need to be overcome to enhance the treatment efficacy of immunotherapies on bone metastasis. While it is apparent that further investigation is needed regarding immunotherapeutic treatment efficacy in patients with bone metastasis, this therapy may prove to be clinically novel in this subset of cancer patients.

The road of NSCLC stem cells toward bone metastases

Despite advancement in therapeutic options, Non-Small Cell lung cancer (NSCLC) remains a lethal disease mostly due to late diagnosis at metastatic phase and drug resistance. Bone is one of the more frequent sites for NSCLC metastatization. A defined subset of cancer stem cells (CSCs) that possess motile properties, mesenchymal features and tumor initiation potential are defined as metastasis initiating cells (MICs). A better understanding of the mechanisms supporting MIC dissemination and interaction with bone microenvironment is fundamental to design novel rational therapeutic option for long lasting efficient treatment of NSCLC. In this review we will summarize findings about bone metastatic process initiated by NSCLC MICs. We will review how MICs can reach bone and interact with its microenvironment that supports their extravasation, seeding, dormancy/proliferation. The role of different cell types inside the bone metastatic niche, such as endothelial cells, bone cells, hematopoietic stem cells and immune cells will be discussed in regards of their impact in dictating the success of metastasis establishment by MICs. Finally, novel therapeutic options to target NSCLC MIC-induced bone metastases, increasing the survival of patients, will be presented.

Case report: Complete remission of bone metastasis from renal cell carcinoma in histopathological examination after treatment with immune checkpoint inhibitors

Recently, the prognosis of metastatic renal cell carcinoma (mRCC) has improved owing to the development of immunotherapy using immune checkpoint inhibitors (ICIs). However, there have been few studies on the therapeutic effect of ICIs in bone metastases from renal cell carcinoma (RCC). We report a case in which pulmonary and humeral metastases from RCC were significantly ameliorated using ICIs, while surgery for a pathological fracture of the humerus significantly improved the patient’s quality of life (QoL). A 70-year-old man who underwent a left nephrectomy for RCC developed multiple pulmonary metastases and humeral metastasis with a pathological fracture one year after surgery, and combined treatment with nivolumab and ipilimumab was initiated. After four courses of ICI treatment, multiple pulmonary metastases had almost disappeared, and the tumor at the fracture site had shrunk remarkably. However, the shoulder joint function had decreased due to the fracture, worsening his QoL. Therefore, he underwent surgery and returned to normal daily life one month after. Postoperative histopathological examination of bone and soft tissue at the fracture site revealed no malignancy. To our knowledge, this is the first case report of complete remission of bone metastasis of RCC based on histopathological examination with ICI treatment.

The Therapeutic Effect and Clinical Outcome of Immune Checkpoint Inhibitors on Bone Metastasis in Advanced Non-Small-Cell Lung Cancer

Introduction

In advanced non-small-cell lung cancer (NSCLC), immune checkpoint inhibitors (ICIs) have been reported a better treatment outcome on primary lesions, however, the therapeutic effect on bone metastases has not been clarified. This study investigates the therapeutic effect of ICIs on bone metastases in advanced NSCLC.

Methods

The data of patients with advanced NSCLC, treated with ICIs from 2016 to 2019 at our hospital, were analyzed. The therapeutic effects of ICIs on primary lung and metastatic bone lesions, concomitant use of bone modifying agents (BMA), treatment outcomes, and frequency of immune-related adverse events (irAEs) and skeletal-related events (SREs) were investigated.

Results

A total of 29 patients were included (19 men and 10 women; mean age, 64.2 years). Among the ICIs, pembrolizumab was the most used (55.2%), and concomitant use of BMA was prevalent in 21 patients (zoledronic acid=1, denosumab=20). The therapeutic effect was partial response (PR) in 10.3% (n=3) on primary lung lesions by RECIST 1.1, complete response (CR) in 6.9% (n=2) and PR in 17.2% (n=5) on bone metastatic lesions by MDA criteria. ICIs suppressed the progression of bone metastasis in 21 cases (72.4%). All patients in CR and PR were treated with pembrolizumab and denosumab. SREs and irAEs were developed in 3.4% (n=1) and 20.7% (n=6), respectively. The median survival time after treatment with ICIs was 11.0 months. Concomitant therapy with ICIs and denosumab significantly prolonged the overall survival compared to ICI-only therapy (16.0 months vs. 2.5 months, p<0.01).

Conclusions

This study showed that treatment with ICIs may successfully suppress the progression of bone metastasis in advanced NSCLC. Pembrolizumab with denosumab had the highest therapeutic effect on both primary lung lesions and bone metastases. Systemic treatment with this combination and conservative treatment of bone metastasis could be one of the options in the treatment of advanced NSCLC.

The gut microbiota can be a potential regulator and treatment target of bone metastasis

The gut microbiota, an often forgotten organ, have a tremendous impact on human health. It has long been known that the gut microbiota are implicated in cancer development, and more recently, the gut microbiota have been shown to influence cancer metastasis to distant organs. Although one of the most common sites of distant metastasis is the bone, and the skeletal system has been shown to be a subject of interactions with the gut microbiota to regulate bone homeostasis, little research has been done regarding how the gut microbiota control the development of bone metastasis. This review will discuss the mechanisms through which the gut microbiota and derived microbial compounds (i) regulate gastrointestinal cancer disease progression and metastasis, (ii) influence skeletal remodeling and potentially modulate bone metastasis, and (iii) affect and potentially enhance immunotherapeutic treatments for bone metastasis.

Characterizing the Shifting Real-World Treatment Landscape by PD-L1 Testing Status and Expression Level in Advanced Non-Small Cell Lung Cancer

INTRODUCTION

Contemporary real-world data on advanced non-small cell lung cancer (aNSCLC) treatment patterns across programmed cell death-ligand 1 (PD-L1) expression levels and testing status are limited.

METHODS

A retrospective cohort was selected of adults newly diagnosed with aNSCLC between January 1, 2018, and July 31, 2021, who initiated first-line treatments, which were described by PD-L1 status and expression levels (≥ 50%, 1-49%, < 1%). Treatment received before and after PD-L1 test results were described for patients initiating first-line treatment before PD-L1 results. For patients who initiated chemotherapy alone before PD-L1 results, the probability of receiving immune checkpoint inhibitors (ICIs) after PD-L1 results was estimated by PD-L1 level and associated factors were explored.

RESULTS

Among 12,202 patients with aNSCLC initiating first-line treatment [54.7% male, mean (standard deviation) age 69.2 (9.4) years], the most common therapies were ICI-based regimens across PD-L1 levels, and chemotherapy alone among PD-L1-untested patients. Use of chemotherapy alone decreased between 2018 and 2019 and stabilized thereafter, accounting for 21-29% of first-line treatments across PD-L1 levels and 48% of untested patients in 2021. Of 1468 patients initiating first-line treatment before PD-L1 results, treatments remained unchanged in most patients after PD-L1 results. Among patients initiating chemotherapy alone before PD-L1 results, the probability of receiving ICIs within 45 days after test results was 40.5% [95% confidence interval (CI) 31.6-48.3%], 28.6% (95% CI 20.3-36.0%), and 22.9% (95% CI 16.9-28.4%) at PD-L1 ≥ 50%, 1-49%, and < 1%, respectively.

CONCLUSION

While ICI-based regimens accounted for most first-line treatments across PD-L1 levels, chemotherapy alone was initiated in > 20% of patients tested for PD-L1 and 48% of untested patients in 2021. Patients who initiated chemotherapy alone had a low probability of receiving ICIs after PD-L1 test results. These results highlight the need for understanding the role and timing of PD-L1 test results for informing treatment decisions for patients with aNSCLC.

Immune Checkpoint Inhibitor Therapy for Bone Metastases: Specific Microenvironment and Current Situation

The treatment of bone metastases is a thorny issue. Immunotherapy may be one of the few hopes for patients with unresectable bone metastases. Immune checkpoint inhibitors are the most commonly used immunotherapy drugs currently. In this review, the characteristics and interaction of bone metastases and their immune microenvironment were systematically discussed, and the relevant research progress of the immunological mechanism of tumor bone metastasis was reviewed. On this basis, we expounded the clinical application of immune checkpoint inhibitors for bone metastasis of common tumors, including non-small-cell lung cancer, renal cell carcinoma, prostate cancer, melanoma, and breast cancer. Then, the deficiencies and limitations in current researches were summarized. In-depth basic research on bone metastases and optimization of clinical treatment is needed.