Pembrolizumab plus eribulin in hormone-receptor-positive, HER2-negative, locally recurrent or metastatic breast cancer (KELLY): An open-label, multicentre, single-arm, phase Ⅱ trial

Incidence of thyroid dysfunction caused by immune checkpoint inhibitors combined with chemotherapy: A systematic review and meta-analysis

BACKGROUND

The combination of immune checkpoint inhibitors (ICIs) and chemotherapy as a first-line treatment for triple-negative breast cancer (TNBC) has been associated with many adverse reactions. Thyroid dysfunction, the most common adverse reaction of the endocrine system, has also attracted significant attention. This study aimed to analyse the effect of ICIs combined with chemotherapy on thyroid function in patients with TNBC.

METHODS

As of November 4, 2023, we searched the PubMed, Web of Science, and Cochrane Library databases for clinical trials of ICIs combined with chemotherapy for the treatment of TNBC. The incidence of hypothyroidism and hyperthyroidism was calculated using a random-effects model.

RESULTS

In the final analysis, 3,226 patients from 19 studies were included. The total incidence of all-grade hypothyroidism induced by the combination of ICIs and chemotherapy in treating TNBC (12% (95% confidence intervals(CI): 0.10-0.15)) was higher than that of hyperthyroidism (5% (95% CI: 0.04-0.06)). Pembrolizumab combined with chemotherapy caused the highest incidence of all grades of hypothyroidism for 13% (95% CI: 0.05-0.06). Durvalumab combined with chemotherapy caused the highest incidence of all grades of hyperthyroidism, at 7% (95% CI: 0.03-0.11). ICIs combined with chemotherapy caused a higher incidence of all grades of hypothyroidism in advanced TNBC (15% (95% CI: 0.13-0.17)) than in early stage TNBC (10% (95% CI: 0.07-0.13)).

CONCLUSION

In TNBC, the incidence of hypothyroidism caused by the combination of ICIs and chemotherapy was significantly higher than that caused by hyperthyroidism. Pembrolizumab combined with chemotherapy resulted in the highest incidence of hypothyroidism. The incidence of hypothyroidism in patients with advanced TNBC was significantly higher than that in patients with early stage TNBC. In addition, ICIs combined with chemotherapy resulted in 16 out of 3,226 patients experiencing grade ≥ 3 thyroid dysfunction. Although the incidence of severe thyroid dysfunction is low, it requires attention.

PROSPERO

CRD42023477933.

Experimental and clinical evidence in favour of an effective immune stimulation in ER-positive, endocrine-dependent metastatic breast cancer

In ER+ breast cancer, usually seen as the low immunogenic type, the main mechanisms favouring the immune response or tumour growth and immune evasion in the tumour microenvironment (TME) have been examined. The principal implications of targeting the oestrogen-mediated pathways were also considered. Recent experimental findings point out that anti-oestrogens contribute to the reversion of the immunosuppressive TME. Moreover, some preliminary clinical data with the hormone-immunotherapy association in a metastatic setting support the notion that the reversion of immune suppression in TME is likely favoured by the G0-G1 state induced by anti-oestrogens. Following immune stimulation, the reverted immune suppression allows the boosting of the effector cells of the innate and adaptive immune response. This suggests that ER+ breast cancer is a molecular subtype where a successful active immune manipulation can be attained. If this is confirmed by a prospective multicentre trial, which is expected in light of the provided evidence, the proposed hormone immunotherapy can also be tested in the adjuvant setting. Furthermore, the different rationale suggests a synergistic activity of our proposed immunotherapy with the currently recommended regimen consisting of antioestrogens combined with cyclin kinase inhibitors. Overall, this lays the foundation for a shift in clinical practice within this most prevalent molecular subtype of breast cancer.

Ipilimumab and nivolumab combined with anthracycline-based chemotherapy in metastatic hormone receptor-positive breast cancer: a randomized phase 2b trial

BACKGROUND

Immune checkpoint inhibitors have shown minimal clinical activity in hormone receptor-positive metastatic breast cancer (HR+mBC). Doxorubicin and low-dose cyclophosphamide are reported to induce immune responses and counter regulatory T cells (Tregs). Here, we report the efficacy and safety of combined programmed cell death protein-1/cytotoxic T-lymphocyte-associated protein 4 blockade concomitant with or after immunomodulatory chemotherapy for HR+mBC.

METHODS

Patients with HR+mBC starting first-/second- line chemotherapy (chemo) were randomized 2:3 to chemotherapy (pegylated liposomal doxorubicin 20 mg/m2 every second week plus cyclophosphamide 50 mg by mouth/day in every other 2-week cycle) with or without concomitant ipilimumab (ipi; 1 mg/kg every sixth week) and nivolumab (nivo; 240 mg every second week). Patients in the chemo-only arm were offered cross-over to ipi/nivo without chemotherapy. Co-primary endpoints were safety in all patients starting therapy and progression-free survival (PFS) in the per-protocol (PP) population, defined as all patients evaluated for response and receiving at least two treatment cycles. Secondary endpoints included objective response rate, clinical benefit rate, Treg changes during therapy and assessment of programmed death-ligand 1 (PD-L1), mutational burden and immune gene signatures as biomarkers.

RESULTS

Eighty-two patients were randomized and received immune-chemo (N=49) or chemo-only (N=33), 16 patients continued to the ipi/nivo-only cross-over arm. Median follow-up was 41.4 months. Serious adverse events occurred in 63% in the immune-chemo arm, 39% in the chemo-only arm and 31% in the cross-over-arm. In the PP population (N=78) median PFS in the immune-chemo arm was 5.1 months, compared with 3.6 months in the chemo-only arm, with HR 0.94 (95% CI 0.59 to 1.51). Clinical benefit rates were 55% (26/47) and 48% (15/31) in the immune-chemo and chemo-only arms, respectively. In the cross-over-arm (ipi/nivo-only), objective responses were observed in 19% of patients (3/16) and clinical benefit in 25% (4/16). Treg levels in blood decreased after study chemotherapy. High-grade immune-related adverse events were associated with prolonged PFS. PD-L1 status and mutational burden were not associated with ipi/nivo benefit, whereas a numerical PFS advantage was observed for patients with a high Treg gene signature in tumor.

CONCLUSION

The addition of ipi/nivo to chemotherapy increased toxicity without improving efficacy. Ipi/nivo administered sequentially to chemotherapy was tolerable and induced clinical responses.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Identifier: NCT03409198.

Clinical activity of nivolumab in combination with eribulin in HER2-negative metastatic breast cancer: A phase IB/II study (KCSG BR18-16)

AIM

We evaluated the efficacy and safety of nivolumab and eribulin combination therapy for metastatic breast cancer (BC) in Asian populations.

METHODS

In this parallel phase II study, adult patients with histologically confirmed recurrent/metastatic hormone receptor-positive/HER2-negative (HR+HER2-) or triple-negative BC (TNBC) were prospectively enroled from 10 academic hospitals in Korea (ClinicalTrials.gov Identifier: NCT04061863). They received nivolumab (360 mg) on day 1 plus eribulin (1.4 mg/m2) on days 1 and 8 every 3 weeks until disease progression or intolerable toxicity. The primary endpoint was the investigator-assessed 6-month progression-free survival (PFS) rate in each subtype. Secondary endpoints included investigator-assessed objective response rate (ORR) as per Response Evaluation Criteria in Advanced Solid Tumors version 1.1, disease control rate, overall survival, and treatment toxicity. The association between PD-L1 expression and efficacy was investigated.

RESULTS

Forty-five patients with HR+HER2- BC and 45 with TNBC were enroled. Their median age was 51 (range, 31-71) years, and 74 (82.2%) received one or two prior treatments before enrolment. Six-month PFS was 47.2% and 25.1% in the HR+HER2- and TNBC cohorts, respectively. Median PFS was 5.6 (95% confidence interval [CI]: 5.3-7.4) and 3.0 (95% CI: 2.1-5.2) months in the HR+HER2- and TNBC groups, respectively. ORRs were 53.3% (complete response [CR]: 0, partial response [PR]: 24) and 28.9% (CR: 1, PR: 12). Patients with PD-L1+ tumours (PD-L1 expression ≥1%) and PD-L1- tumours (ORR 50% versus 53.8% in HR+HER2-, 30.8% versus 29.0% in TNBC) had similar ORRs. Neutropenia was the most common grade 3/4 adverse event; the most common immune-related adverse events (AEs) were grades 1/2 hypothyroidism and pruritus. Five patients discontinued therapy because of immune-related AEs.

CONCLUSION

Nivolumab plus eribulin showed promising efficacy and tolerable safety in previously treated HER2- metastatic BC.

TRIAL REGISTRATION

NCT04061863.

Eribulin is an immune potentiator in breast cancer that upregulates human leukocyte antigen class I expression via the induction of NOD-like receptor family CARD domain-containing 5

Eribulin inhibits microtubule polymerization and improves the overall survival of patients with recurrent metastatic breast cancer. A subgroup analysis revealed a low neutrophil to lymphocyte ratio (NLR) (<3) to be a prognostic factor of eribulin treatment. We thus hypothesized that eribulin might be related to the immune response for breast cancer cells and we analyzed the effects of eribulin on the immune system. Immunohistochemical staining revealed that human leukocyte antigen (HLA) class I expression was increased in clinical samples after eribulin treatment. In vitro assays revealed that eribulin treatment increased HLA class I expression in breast cancer line cells. RNA-sequencing demonstrated that eribulin treatment increased the expression of the NOD-like family CARD domain-containing 5 (NLRC5), a master regulator of HLA class I expression. Eribulin treatment increased the NY-ESO-1-specific T-cell receptor (TCR) transduced T (TCR-T) cell response for New York oesophageal squamous cell carcinoma 1 (NY-ESO-1) overexpressed breast cancer cells. The eribulin and TCR-T combined therapy model revealed that eribulin and immunotherapy using TCR-T cells has a synergistic effect. In summary, eribulin increases the expression of HLA class 1 via HLA class 1 transactivatior NLRC5 and eribulin combination with immunotherapy can be effective for the treatment of breast cancer.

Liquid biopsy biomarkers to guide immunotherapy in breast cancer

Immune checkpoint inhibitors (ICIs) therapy has emerged as a promising treatment strategy for breast cancer (BC). However, current reliance on immunohistochemical (IHC) detection of PD-L1 expression alone has limited predictive capability, resulting in suboptimal efficacy of ICIs for some BC patients. Hence, developing novel predictive biomarkers is indispensable to enhance patient selection for immunotherapy. In this context, utilizing liquid biopsy (LB) can provide supplementary or alternative value to PD-L1 IHC testing for identifying patients most likely to benefit from immunotherapy and exhibit favorable responses. This review discusses the predictive and prognostic value of LB in breast cancer immunotherapy, as well as its limitations and future directions. We aim to promote the individualization and precision of immunotherapy in BC by elucidating the role of LB in clinical practice.

Pyroptosis-related gene signatures are associated with prognosis and tumor microenvironment infiltration in head and neck cancer

Background and Aims

Recent studies have highlighted the biological significance of pyroptosis in cancer development. Nevertheless, it is still uncertain if pyroptosis also plays a part in immune modulation and the creation of the tumor microenvironment (TME).

Methods

The pyroptosis regulatory genes (PRGs) were comprehensively assessed in 1938 head and neck cancer samples, and systematically correlated these modification patterns with the infiltration characteristics of TME cells. The unsupervised consensus analysis method was used to identify specific pyroptosis clusters. The single-sample gene set enrichment analysis and CIBERSOFT algorithms were used to evaluate the infiltration levels of various immune cell subsets. A principal component analysis algorithm was used to construct the pyrolysis potential index (PPI) to quantify the pyrolysis regulation patterns in head and neck squamous cell carcinoma (HNSC).

Results

Pyrophosphate regulatory genes (PRGs) are often upregulated in tumors due to mutations. PRGs relate to various clinical outcomes and pathways. Molecular subtyping identified pyroptosis patterns, which align with three tumor immunophenotypes: immune-inflamed, immune-excluded, and immune-desert. The PPI measures pyrolysis roles, showing higher PPI in tumor samples linked to subtypes and clinical characteristics. Lower PPI correlates with longer survival, increased immune activity, more tumor mutations, high PD-L1 expression, and mutations in significant genes like PIK3CA. Such patients also experience enhanced immune responses in immunotherapy trials.

Conclusion

We conducted a comprehensive examination of pyroptosis in HNSC and developed a PPI indicator that shows a strong correlation with the variety and intricacy of the TME.

Recent Developments in the Therapeutic Landscape of Advanced or Metastatic Hormone Receptor-Positive Breast Cancer

Hormone receptor-positive (HR+) disease is the most frequently diagnosed subtype of breast cancer. Among tumor subtypes, natural course of HR+ breast cancer is indolent with favorable prognosis compared to other subtypes such as human epidermal growth factor protein 2-positive disease and triple-negative disease. HR+ tumors are dependent on steroid hormone signaling and endocrine therapy is the main treatment option. Recently, the discovery of cyclin-dependent kinase 4/6 inhibitors and their synergistic effects with endocrine therapy has dramatically improved treatment outcome of advanced HR+ breast cancer. The demonstrated efficacy of additional nonhormonal agents, such as targeted therapy against mammalian target of rapamycin and phosphatidylinositol 3-kinase signaling, poly(ADP-ribose) polymerase inhibitors, antibody-drug conjugates, and immunotherapeutic agents have further expanded the available therapeutic options. This article reviews the latest advancements in the treatment of HR+ breast cancer, and in doing so discusses not only the development of currently available treatment regimens but also emerging therapies that invite future research opportunities in the field.

Systemic therapy for hormone receptor-positive/human epidermal growth factor receptor 2-negative early stage and metastatic breast cancer

Hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer is defined by the presence of the estrogen receptor and/or the progesterone receptor and the absence of HER2 gene amplification. HR-positive/HER2-negative breast cancer accounts for 65%-70% of all breast cancers, and incidence increases with increasing age. Treatment varies by stage, and endocrine therapy is the mainstay of treatment in both early stage and late-stage disease. Combinations with cyclin-dependent kinase 4/6 inhibitors have reduced distant recurrence in the early stage setting and improved overall survival in the metastatic setting. Chemotherapy is used based on stage and tumor biology in the early stage setting and after endocrine resistance for advanced disease. New therapies, including novel endocrine agents and antibody-drug conjugates, are now changing the treatment landscape. With the availability of new treatment options, it is important to define the optimal sequence of treatment to maximize clinical benefit while minimizing toxicity. In this review, the authors first discuss the pathologic and molecular features of HR-positive/HER2-negative breast cancer and mechanisms of endocrine resistance. Then, they discuss current and emerging therapies for both early stage and metastatic HR-positive/HER2-negative breast cancer, including treatment algorithms based on current data.

Advancements in clinical aspects of targeted therapy and immunotherapy in breast cancer

Breast cancer is the second leading cause of death for women worldwide. The heterogeneity of this disease presents a big challenge in its therapeutic management. However, recent advances in molecular biology and immunology enable to develop highly targeted therapies for many forms of breast cancer. The primary objective of targeted therapy is to inhibit a specific target/molecule that supports tumor progression. Ak strain transforming, cyclin-dependent kinases, poly (ADP-ribose) polymerase, and different growth factors have emerged as potential therapeutic targets for specific breast cancer subtypes. Many targeted drugs are currently undergoing clinical trials, and some have already received the FDA approval as monotherapy or in combination with other drugs for the treatment of different forms of breast cancer. However, the targeted drugs have yet to achieve therapeutic promise against triple-negative breast cancer (TNBC). In this aspect, immune therapy has come up as a promising therapeutic approach specifically for TNBC patients. Different immunotherapeutic modalities including immune-checkpoint blockade, vaccination, and adoptive cell transfer have been extensively studied in the clinical setting of breast cancer, especially in TNBC patients. The FDA has already approved some immune-checkpoint blockers in combination with chemotherapeutic drugs to treat TNBC and several trials are ongoing. This review provides an overview of clinical developments and recent advancements in targeted therapies and immunotherapies for breast cancer treatment. The successes, challenges, and prospects were critically discussed to portray their profound prospects.

PD-L1 blockade in combination with carboplatin as immune induction in metastatic lobular breast cancer: the GELATO trial

Invasive lobular breast cancer (ILC) is the second most common histological breast cancer subtype, but ILC-specific trials are lacking. Translational research revealed an immune-related ILC subset, and in mouse ILC models, synergy between immune checkpoint blockade and platinum was observed. In the phase II GELATO trial ( NCT03147040 ), patients with metastatic ILC were treated with weekly carboplatin (area under the curve 1.5 mg ml-1 min-1) as immune induction for 12 weeks and atezolizumab (PD-L1 blockade; triweekly) from the third week until progression. Four of 23 evaluable patients had a partial response (17%), and 2 had stable disease, resulting in a clinical benefit rate of 26%. From these six patients, four had triple-negative ILC (TN-ILC). We observed higher CD8+ T cell infiltration, immune checkpoint expression and exhausted T cells after treatment. With this GELATO trial, we show that ILC-specific clinical trials are feasible and demonstrate promising antitumor activity of atezolizumab with carboplatin, particularly for TN-ILC, and provide insights for the design of highly needed ILC-specific trials.

Immune Checkpoint Inhibitors and Novel Immunotherapy Approaches for Breast Cancer

PURPOSE OF REVIEW

To critically review the existing evidence on immune checkpoint inhibitors (ICIs) in early-stage and metastatic breast cancer and discuss emerging strategies in the different breast cancer subtypes.

RECENT FINDINGS

Immunotherapy has become one of the major milestones in contemporary oncology, revolutionizing the treatment of multiple solid tumors. ICI agents combined with chemotherapy have demonstrated significant efficacy in both early-stage and metastatic triple-negative breast cancer. However, only a subgroup of patients responds to those agents and some associated toxicities, although infrequent, can be life-disabling. Emerging data from immunotherapy studies in advanced hormone receptor-positive (HR +) breast cancer as well as HER2-positive disease are arising with mixed results. Although breast cancer has not classically been considered a hot tumor, ICIs have proven to be effective in a subset of breast cancer patients. However, much remains to be learned, and the identification of new biomarkers beyond PD-L1 expression is essential not only to improve the efficacy of ICI but also to identify patients who can avoid them, together with their toxicities and costs.

Multiplexed In Situ Spatial Protein Profiling in the Pursuit of Precision Immuno-Oncology for Patients with Breast Cancer

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of many solid tumors. In breast cancer (BC), immunotherapy is currently approved in combination with chemotherapy, albeit only in triple-negative breast cancer. Unfortunately, most patients only derive limited benefit from ICIs, progressing either upfront or after an initial response. Therapeutics must engage with a heterogeneous network of complex stromal-cancer interactions that can fail at imposing cancer immune control in multiple domains, such as in the genomic, epigenomic, transcriptomic, proteomic, and metabolomic domains. To overcome these types of heterogeneous resistance phenotypes, several combinatorial strategies are underway. Still, they can be predicted to be effective only in the subgroups of patients in which those specific resistance mechanisms are effectively in place. As single biomarker predictive performances are necessarily suboptimal at capturing the complexity of this articulate network, precision immune-oncology calls for multi-omics tumor microenvironment profiling in order to identify unique predictive patterns and to proactively tailor combinatorial treatments. Multiplexed single-cell spatially resolved tissue analysis, through precise epitope colocalization, allows one to infer cellular functional states in view of their spatial organization. In this review, we discuss-through the lens of the cancer-immunity cycle-selected, established, and emerging markers that may be evaluated in multiplexed spatial protein panels to help identify prognostic and predictive patterns in BC.

Combinatorial Strategies With PD-1/PD-L1 Immune Checkpoint Blockade for Breast Cancer Therapy: Mechanisms and Clinical Outcomes

As an emerging antitumor strategy, immune checkpoint therapy is one of the most promising anticancer therapies due to its long response duration. Antibodies against the programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) axis have been extensively applied to various cancers and have demonstrated unprecedented efficacy. Nevertheless, a poor response to monotherapy with anti-PD-1/PD-L1 has been observed in metastatic breast cancer. Combination therapy with other standard treatments is expected to overcome this limitation of PD-1/PD-L1 blockade in the treatment of breast cancer. In the present review, we first illustrate the biological functions of PD-1/PD-L1 and their role in maintaining immune homeostasis as well as protecting against immune-mediated tissue damage in a variety of microenvironments. Several combination therapy strategies for the combination of PD-1/PD-L1 blockade with standard treatment modalities have been proposed to solve the limitations of anti-PD-1/PD-L1 treatment, including chemotherapy, radiotherapy, targeted therapy, antiangiogenic therapy, and other immunotherapies. The corresponding clinical trials provide valuable estimates of treatment effects. Notably, several combination options significantly improve the response and efficacy of PD-1/PD-L1 blockade. This review provides a PD-1/PD-L1 clinical trial landscape survey in breast cancer to guide the development of more effective and less toxic combination therapies.

Identification of pyroptosis related subtypes and tumor microenvironment infiltration characteristics in breast cancer

Understanding the association of pyroptosis with tumor progression, prognosis and effect on immunotherapeutic response in breast cancer (BC) is limited. This study analysed forty pyroptosis-related genes to construct the pyroptosis score. Association of the pyroptosis score with the overall survival, clinical features, tumor mutation load, immune cell infiltration, and treatment sensitivity of patients with BC was analysed. Out of 983 BC samples, 304 (30.93%) had genetic alterations with the highest TP53 frequency. We identified three separate subtypes associated with pyroptosis action. These subtypes correlate with the clinicopathological characteristics, TME immune cell infiltration, and disease prognosis. Based on the expression levels of the pyroptosis genes, we divided the pyroptosis score into a high group and a low group. The immune-activated pyroptosis subtype had a higher score with a better prognosis. We also observed that the pyroptosis score correlates with the tumor mutation burden. The pyroptosis score and disease prognosis were directly proportional. A higher pyroptosis score indicated a better prognosis. Results suggest that the pyroptosis-related gene prognosis model is closely related to the immune cell infiltration of BC. The three pyroptosis subtypes associated with BC assist in accurately identifying the tumor subtype, the prognosis of immunotherapy drugs and the patient’s therapeutic response.

Current Treatment and Future Trends of Immunotherapy in Breast Cancer

Immunotherapy continues to redefine the solid tumor treatment landscape with inhibitors of the PD-L1/PD-1 immune checkpoint having the most widespread impact. As the most common cancer diagnosed worldwide, there is significant interest in the development of immunotherapy for the treatment of breast cancer in both the early and metastatic settings. Recently reported results of several clinical trials have identified potential roles for immunotherapy agents alone or in combination with standard treatment for early and metastatic disease. While trials to date have been promising, immunotherapy thus far has been shown to benefit only a select group of patients with breast cancer, defined by tumor subtype, PD-L1 expression, and line of therapy. With over 250 trials ongoing, emerging data will enable the further refinement of breast cancer immunotherapy strategies. The integration of multiple putative biomarkers and consideration of dynamic markers of early response or resistance may inform optimal patient selection for immunotherapy investigation and integration into clinical practice. This review will summarize the current evidence for immune-checkpoint blockade (ICB) in the treatment of early and metastatic breast cancer and highlight current and potential future biomarkers of therapeutic response.

Immunotherapy in Breast Cancer and the Potential Role of Liquid Biopsy

Liquid biopsy biomarkers, such as circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA), are noninvasive diagnostics that could complement predictive and prognostic tools currently used in the clinic. Recent trials of immunotherapy have shown promise in improving outcomes in a subset of breast cancer patients. Biomarkers could improve the efficacy of immune checkpoint inhibitors by identifying patients whose cancers are more likely to respond to immunotherapy. In this review, we discuss the current applications of liquid biopsy and emerging technologies for evaluation of immunotherapy response and outcomes in breast cancer. We also provide an overview of the status of immunotherapy in breast cancer.

Understanding resistance to immune checkpoint inhibitors in advanced breast cancer

INTRODUCTION

The addition of immune checkpoint inhibitors (ICIs) to frontline chemotherapy has improved survival for patients with advanced triple-negative breast cancer (TNBC) expressing programmed death-ligand 1 (PD-L1). Nonetheless, most patients develop resistance, with outcomes remaining poor for this population. Moreover, unsatisfactory activity has been observed with ICIs in PD-L1-negative TNBC and in other breast cancer (BC) subtypes, warranting a deeper understanding of resistance to ICIs in BC.

AREAS COVERED

We discuss the immune landscape of distinct BC subtypes, review the clinical activity of immunotherapy in BC, and highlight strategies under development to overcome resistance to ICIs.

EXPERT OPINION

Activity and resistance to ICIs in BC are strongly related to the intrinsic immunophenotype of the tumor tissue. Several promising biomarkers reflecting the immunological state of BC are emerging, with only PD-L1 expression currently adopted into clinical practice. However, limitations make of PD-L1 a sub-optimal biomarker for patient selection, which require efforts to integrate this marker with other immunological features. Concomitantly, a wide variety of drug combinations designed to overcome immune-resistance are being evaluated, with some encouraging signals observed in early-phase trials. Combination strategies tailored to patient and tumor immunophenotype may allow to overcome resistance and fully exploit the potential of ICIs.

Assessing PD-L1 Expression Status Using Radiomic Features from Contrast-Enhanced Breast MRI in Breast Cancer Patients: Initial Results

Simple Summary

To our knowledge, this is the first study assessing radiomics coupled with machine learning from MRI-derived features to predict PD-L1 expression status in biopsy-proven triple negative breast cancers and comparing the performance of this approach with the performance of qualitative assessment by two radiologists. This pilot study shows that radiomics analysis coupled with machine learning of DCE-MRI is a promising approach to derive prognostic and predictive information and to select patients who could benefit from anti-PD-1/PD-L1 treatment. This technique could also be used to monitor PD-L1 expression, as it can vary over time and between different regions of the tumor, thus avoiding repeated biopsies.

Abstract

The purpose of this retrospective study was to assess whether radiomics analysis coupled with machine learning (ML) based on standard-of-care dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can predict PD-L1 expression status in patients with triple negative breast cancer, and to compare the performance of this approach with radiologist review. Patients with biopsy-proven triple negative breast cancer who underwent pre-treatment breast MRI and whose PD-L1 status was available were included. Following 3D tumor segmentation and extraction of radiomic features, radiomic features with significant differences between PD-L1+ and PD-L1− patients were determined, and a final predictive model to predict PD-L1 status was developed using a coarse decision tree and five-fold cross-validation. Separately, all lesions were qualitatively assessed by two radiologists independently according to the BI-RADS lexicon. Of 62 women (mean age 47, range 31–81), 27 had PD-L1− tumors and 35 had PD-L1+ tumors. The final radiomics model to predict PD-L1 status utilized three MRI parameters, i.e., variance (FO), run length variance (RLM), and large zone low grey level emphasis (LZLGLE), for a sensitivity of 90.7%, specificity of 85.1%, and diagnostic accuracy of 88.2%. There were no significant associations between qualitative assessed DCE-MRI imaging features and PD-L1 status. Thus, radiomics analysis coupled with ML based on standard-of-care DCE-MRI is a promising approach to derive prognostic and predictive information and to select patients who could benefit from anti-PD-1/PD-L1 treatment.

A review of immune checkpoint blockade in breast cancer

In the recent years characterized by the cancer immunotherapy revolution, attention has turned to how to potentially boost and/or generate an efficient anti-tumor immune response in breast cancer (BC). Clinical activity of immune checkpoint blockade (ICB) targeting PD-1 or PD-L1 in BC has been more evident in the triple negative subtype and in earlier lines of the treatment. Remarkably, some responders to single agent ICB have achieved durable responses with metastatic disease, possibly as a result of treatment-induced immunological memory. However, most BC are immunologically quiescent and current research efforts developing ICB combinations are attempting to convert "cold" into "hot" tumors by manipulating the tumor microenvironment, expanding anti-tumor T cells improving efficient antigen presentation, and suppressing pro-tumor inhibitory cells. The aim of this review is to summarize existing data on the efficacy of immune checkpoint blockers as single agents and combination strategies in all BC subtypes, highlighting the BC subgroups that benefit most from ICB.

Immunomodulating Therapies in Breast Cancer-From Prognosis to Clinical Practice

The role of the immune system in breast cancer has been debated for decades. The advent of technologies such as next generation sequencing (NGS) has elucidated the crucial interplay between somatic mutations in tumors leading to neoantigens and immune responses with increased tumor-infiltrating lymphocytes and improved prognosis of breast cancer patients. In particular, triple-negative breast cancer (TNBC) has a higher mutational burden compared to other breast cancer subtypes. In addition, higher levels of tumor-associated antigens suggest that immunotherapies are a promising treatment option, specifically for TNBC. Indeed, higher concentrations of tumor-infiltrating lymphocytes are associated with better prognosis and response to chemotherapy in TNBC. An important target within the cancer immune cell cycle is the "immune checkpoint". Immune checkpoint inhibitors (ICPis) block the interaction of certain cell surface proteins that act as "brakes" on immune responses. Recent studies have shown that ICPis improve survival in both early and advanced TNBC. However, this comes at the price of increased toxicity, particularly immune-mediated toxicity. As an alternative approach, individualized mRNA vaccination strategies against tumor-associated neoantigens represent another promising approach leading to neoantigen-specific immune responses. These novel strategies should help to improve treatment outcomes, especially for patients with triple negative breast cancer.

Molecular correlates of response to eribulin and pembrolizumab in hormone receptor-positive metastatic breast cancer

Immune checkpoint inhibitors (ICIs) have minimal therapeutic effect in hormone receptor-positive (HR+ ) breast cancer. We present final overall survival (OS) results (n = 88) from a randomized phase 2 trial of eribulin ± pembrolizumab for patients with metastatic HR+ breast cancer, computationally dissect genomic and/or transcriptomic data from pre-treatment tumors (n = 52) for molecular associations with efficacy, and identify cytokine changes differentiating response and ICI-related toxicity (n = 58). Despite no improvement in OS with combination therapy (hazard ratio 0.95, 95% CI 0.59-1.55, p = 0.84), immune infiltration and antigen presentation distinguished responding tumors, while tumor heterogeneity and estrogen signaling independently associated with resistance. Moreover, patients with ICI-related toxicity had lower levels of immunoregulatory cytokines. Broadly, we establish a framework for ICI response in HR+ breast cancer that warrants diagnostic and therapeutic validation. ClinicalTrials.gov Registration: NCT03051659.