Efficacy and safety of neoadjuvant immune checkpoint inhibitors in early-stage triple-negative breast cancer: a systematic review and meta-analysis

Advancing Breast Cancer Treatment: The Role of Immunotherapy and Cancer Vaccines in Overcoming Therapeutic Challenges

Breast cancer (BC) remains a significant global health challenge due to its complex biology, which complicates both diagnosis and treatment. Immunotherapy and cancer vaccines have emerged as promising alternatives, harnessing the body's immune system to precisely target and eliminate cancer cells. However, several key factors influence the selection and effectiveness of these therapies, including BC subtype, tumor mutational burden (TMB), tumor-infiltrating lymphocytes (TILs), PD-L1 expression, HER2 resistance, and the tumor microenvironment (TME). BC subtypes play a critical role in shaping treatment responses. Triple-negative breast cancer (TNBC) exhibits the highest sensitivity to immunotherapy, while HER2-positive and hormone receptor-positive (HR+) subtypes often require combination strategies for optimal outcomes. High TMB enhances immune responses by generating neoantigens, making tumors more susceptible to immune checkpoint inhibitors (ICIs); whereas, low TMB may indicate resistance. Similarly, elevated TIL levels are associated with better immunotherapy efficacy, while PD-L1 expression serves as a key predictor of checkpoint inhibitor success. Meanwhile, HER2 resistance and an immunosuppressive TME contribute to immune evasion, highlighting the need for multi-faceted treatment approaches. Current breast cancer immunotherapies encompass a range of targeted treatments. HER2-directed therapies, such as trastuzumab and pertuzumab, block HER2 dimerization and enhance antibody-dependent cellular cytotoxicity (ADCC), while small-molecule inhibitors, like lapatinib and tucatinib, suppress HER2 signaling to curb tumor growth. Antibody-drug conjugates (ADCs) improve tumor targeting by coupling monoclonal antibodies with cytotoxic agents, minimizing off-target effects. Meanwhile, ICIs, including pembrolizumab, restore T-cell function, and CAR-macrophage (CAR-M) therapy leverages macrophages to reshape the TME and overcome immunotherapy resistance. While immunotherapy, particularly in TNBC, has demonstrated promise by eliciting durable immune responses, its efficacy varies across subtypes. Challenges such as immune-related adverse events, resistance mechanisms, high costs, and delayed responses remain barriers to widespread success. Breast cancer vaccines-including protein-based, whole-cell, mRNA, dendritic cell, and epitope-based vaccines-aim to stimulate tumor-specific immunity. Though clinical success has been limited, ongoing research is refining vaccine formulations, integrating combination therapies, and identifying biomarkers for improved patient stratification. Future advancements in BC treatment will depend on optimizing immunotherapy through biomarker-driven approaches, addressing tumor heterogeneity, and developing innovative combination therapies to overcome resistance. By leveraging these strategies, researchers aim to enhance treatment efficacy and ultimately improve patient outcomes.

Identifying subgroups deriving the most benefit from PD-1 checkpoint inhibition plus chemotherapy in advanced metastatic triple-negative breast cancer: a systematic review and meta-analysis

BACKGROUND

The combination of immunotherapy and chemotherapy has demonstrated an enhancement in progression-free survival (PFS) for individuals with advanced and metastatic triple-negative breast cancer (TNBC) when compared to the use of chemotherapy alone. Nevertheless, the extent to which different subgroups of metastatic TNBC patients experience this benefit remains uncertain.

OBJECTIVES

Our objective was to conduct subgroup analyses to more precisely identify the factors influencing these outcomes.

MATERIALS AND METHODS

The PubMed database was searched until Dec 2023 for studies that compared PD-1 checkpoint inhibitors plus chemotherapy (ICT) with chemotherapy (CT) alone. The primary outcome of interest was progression-free survival (PFS). Review Manager (RevMan) version 5.4. was used for the data analysis.

RESULTS

Four randomized controlled trials (RCTs) comprising 2468 advanced and metastatic TNBC were included in this systematic review and meta-analysis. PFS surge with combined therapy was observed in White (HR 0.80 [0.70, 0.91], p = 0.0007) and Asian ethnicities (HR 0.73 [0.58, 0.93], p = 0.01) but not in Blacks (HR 0.72 [0.42, 1.24], p = 0.24). Overall, patients with distant metastasis demonstrated to derive the PFS benefit from additional immunotherapy (HR 0.87 [0.77, 0.99], p = 0.03); however, metastasis to individual distant site was associated with failure to achieve any treatment difference (Bone: HR 0.79 [0.41, 1.52], p = 0.49; Lung: HR 0.85 [0.70, 1.04], p = 0.11; Liver: HR 0.80 [0.64, 1.01], p = 0.06). While number of metastases > 3 also showed to impact the PFS advantage (HR 0.89 [0.69, 1.16], p = 0.39). While patients, regardless of prior chemotherapy, experienced a notable enhancement in PFS with ICT (Overall: HR 0.79 [0.71, 0.88], p < 0.0001; Yes: HR 0.87 [0.76, 1.00], p = 0.05; No: HR 0.67 [0.56, 0.80], p < 0.00001), those previously exposed to chemotherapy exhibited a significantly smaller PFS advantage compared to those without prior chemotherapy, as evidenced by a significant subgroup difference (Test for subgroup difference: P = 0.02, I2 = 82.2%). Patients lacking PD-L1 expression also failed to achieve any additional benefit from immunotherapy (PD-L1-: HR 0.95 [0.81, 1.12]; p = 0.54; PD-L1+: HR 0.73 [0.64, 0.85], p < 0.0001). Age, ECOG status, and presentation with de novo metastasis/recurrent shown no impact on IT-associated PFS advantage.

CONCLUSIONS

Patient- and treatment- related factors such as ethnicity, distant metastases, number of metastases (> 3), previous exposure to chemotherapy and PD-L1 expression, seem to influence or restrict the advantage in progression-free survival associated with the addition of immunotherapy to chemotherapy, as opposed to chemotherapy alone, in patients with advanced and metastatic TNBC. Larger studies are warranted to validate these outcomes.

Optimizing Neoadjuvant Treatment Response Prediction for Triple-Negative Breast Cancer Using Clinical Trial Data and Deep Auxiliary Learning

Motivation

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with limited treatment options and poor prognosis. Developing predictive models for TNBC treatment responses is crucial but challenging due to data scarcity and the reliance on cell line data, which limits clinical translational value. Leveraging omics data from clinical trials, particularly through auxiliary learning, offers a potential solution to enhance predictive accuracy and reduce data requirements.

Results

In this study, we propose a new approach utilizing deep auxiliary task reweighting learning methods to automatically reweight auxiliary tasks, thereby optimizing the performance of the primary task of predicting TNBC treatment responses. We benchmark various auxiliary learning methods, including ARML, AdaLoss, GradNorm, and OL AUX, against traditional supervised machine learning algorithms and single-task learning baselines. Our results characterize the performance of auxiliary learning across various contexts, including utilizing parallel treatment arms within a multi-arm clinical trial, leveraging treatment arms from different clinical trials, and integrating multiple arms with the same treatment regimens across separate clinical trials. The last scenario also provides an opportunity for validating prediction models on an independent dataset, demonstrating the superior performance of the auxiliary learning models in predicting pathological complete response (pCR) in TNBC patients treated with standardized combinational chemotherapy with Taxane, Anthracycline, and Cyclophosphamide (TAC).

Availability and Implementation

Source code and additional resources can be accessed at https://github.com/moonchangin/DeepAux TxPred TNBC.

The immunoregulatory role of gut microbiota in the incidence, progression, and therapy of breast cancer

Breast cancer (BrCa) is the most prevalent malignant tumor in women and one of the leading causes of female mortality. Its occurrence and progression are influenced by various factors, including genetics, environment, lifestyle, and hormones. In recent years, the gut microbiota has been identified as a significant factor affecting BrCa. The gut microbiota refers to the collective population of various microorganisms in the human gastrointestinal tract. Gut microbiota is closely associated with human health and disease development, participating in crucial physiological functions such as digestion, metabolism, immune response, and neural regulation. It has been found to influence the occurrence and treatment of BrCa through a variety of mechanisms. This article aims to review the immunomodulatory role of the gut microbiota in the development and treatment of BrCa.

Efficacy and safety of a combination treatment of immune checkpoint inhibitors in metastatic breast cancer: a systematic review and meta-analysis

PURPOSE

Immune checkpoint inhibitors (ICIs) in combination with chemotherapy have showed its benefits in clinical studies, and here we conducted a further evaluation on the safety and efficacy of this treatment strategy.

METHODS

A systematic literature review was conducted in PubMed, Embase and Cochrane Library to identify clinical studies on ICIs and chemotherapy for metastatic breast cancer. The primary efficacy endpoints were progression-free survival (PFS) and overall survival (OS), and adverse events (AEs) were analyzed. Random or fixed effects models were used to estimate pooled Hazard ratio (HR), odds ratio (OR) and the data of 95% confidence interval (CI) depend on the Heterogeneity. Cochrane risk assessment tool was used to assess risk of bias. We also drew forest plots and funnel plots, respectively.

RESULTS

Seven studies with intend-to-treat (ITT) population for 3255 patients were analyzed. ICIs pooled therapy showed clinical benefits compared with chemotherapy alone, improving PFS (HR = 0.81, 95% CI: 0.74-0.90) of patients with metastatic triple negative breast cancer (mTNBC), especially in patients with PD-L1-positive tumors. However, it had no effect on OS (HR = 0.92, 95% CI 0.85-1.01). Besides, mTNBC patients received pooled therapy were less frequently to have AEs (OR = 1.30, 95% CI: 1.09-1.54). In patients with metastatic Human Epidermal Growth Factor Receptor 2 (HER2) negative breast cancer, pooled therapy showed no benefit for PFS (HR = 0.80, 95% CI: 0.50-1.28) and OS (HR = 0.87, 95% CI: 0.48-1.58).

CONCLUSION

Pooled therapy had improved PFS in mTNBC patients, especially in patients with PD-L1-positive tumors, and it was less likely to cause grade ≥ 3 AEs.

Long-term survival after neoadjuvant therapy for triple-negative breast cancer under different treatment regimens: a systematic review and network meta-analysis

BACKGROUND

Triple-negative breast cancer (TNBC) is a life-threatening subtype of breast cancer with limited treatment options. Therefore, this network meta-analysis (NMA) aimed to evaluate and compare the effect of various neoadjuvant chemotherapy (NCT) options on the long-term survival of patients with TNBC.

METHODS

PubMed, Embase, Medline, Cochrane Library, Web of Science, and major international conference databases were systematically searched for randomized controlled trials (RCTs) on the efficacy of various NCT options in patients with TNBC. Searches were performed from January 2000 to June 2023. Study heterogeneity was assessed using the I2 statistic. Hazard ratios (HRs) and 95% confidence intervals (CIs) were used to evaluate disease-free survival (DFS) and overall survival (OS). Odds ratios (ORs) and 95% CIs were used to evaluate the pathologic complete response (pCR). The primary outcome was DFS.

RESULTS

We conducted an NMA of 21 RCTs involving 8873 patients with TNBC. Our study defined the combination of anthracyclines and taxanes as the preferred treatment option. On this basis, the addition of any of the following new drugs is considered a new treatment option: bevacizumab (B), platinum (P), poly-ADP-ribose polymerase inhibitors (PARPi), and immune checkpoint inhibitor (ICI). Based on the surface under the cumulative ranking curve (SUCRA) values, the top three SUCRA area values of DFS were taxanes, anthracycline, and cyclophosphamide (TAC; 89.23%); CT (84.53%); and B (81.06%). The top three SUCRA area values of OS were CT (83.70%), TAC (62.02%), and B-containing regimens (60.06%). The top three SUCRA area values of pCR were B + P-containing regimens (82.7%), ICI + P-containing regimens (80.2%), and ICI-containing regimens (61.8%).

CONCLUSIONS

This NMA showed that standard chemotherapy is a good choice with respect to long-term survival. Moreover, B associated with P-containing regimens is likely to be the optimal treatment option for neoadjuvant TNBC in terms of pCR.

Targeted Therapies and Drug Resistance in Advanced Breast Cancer, Alternative Strategies and the Way beyond

"Targeted therapy" or "precision medicine" is a therapeutic strategy launched over two decades ago. It relies on drugs that inhibit key molecular mechanisms/pathways or genetic/epigenetic alterations that promote different cancer hallmarks. Many clinical trials, sponsored by multinational drug companies, have been carried out. During this time, research has increasingly uncovered the complexity of advanced breast cancer disease. Despite high expectations, patients have seen limited benefits from these clinical trials. Commonly, only a minority of trials are successful, and the few approved drugs are costly. The spread of this expensive therapeutic strategy has constrained the resources available for alternative research. Meanwhile, due to the high cost/benefit ratio, other therapeutic strategies have been proposed by researchers over time, though they are often not pursued due to a focus on precision medicine. Notable among these are drug repurposing and counteracting micrometastatic disease. The former provides an obvious answer to expensive targeted therapies, while the latter represents a new field to which efforts have recently been devoted, offering a "way beyond" the current research.

Expanding the PD-L1 Paradigm: A Comprehensive Systematic Review and Meta-Analysis of Scoring Systems and Additional Biomarkers Influencing Immune Checkpoint Inhibitor Outcomes in Breast Cancer

OBJECTIVES

The study aimed to conduct an in-depth analysis of the influence of PD-L1 status and expression levels and other variables on the effectiveness of immune checkpoint inhibitors (ICIs) in treating breast cancer.

METHODS

A total of 19 articles, involving 16 trials and 7899 patients, were included in the analysis. The outcomes of interest were odds-ratio (OR) for pathological complete response (pCR) in early breast cancer, and hazard ratio (HR) for progression-free survival (PFS) and overall survival (OS) in advanced breast cancer.

RESULTS

In early breast cancer, individuals with PD-L1-positive tumors were more likely to benefit from ICIs than those with PD-L1-negative tumors. Furthermore, patients with PD-L1 positivity in immune cells (IC) had superior outcomes compared to those scoring positively on combined positive score (CPS), with ORs for ICIs benefit being 2.28 for IC-positive patients vs 1.78 for CPS-positive patients. Regarding the impact of breast cancer subtypes on the efficacy of ICIs, our findings indicated that triple-negative breast cancer (TNBC) exhibits the greatest therapeutic response with OR of 1.93, followed by the hormone receptor-positive (HoR+) / human epidermal growth factor receptor 2-negative (HER2-), while the HER2+ was the worst. Additionally, age was identified as a key predictive factor in responding to ICIs. In advanced breast cancer, there was an upward trend in CPS values associated with enhanced ICIs responsiveness, with the predictive value increasing from 12% at a CPS threshold of 10 to 13.6% at 20.

CONCLUSION

The study concluded that the PD-L1 expression scoring system effectively discriminates between patients with breast cancer in terms of the degree of benefit they may attain from ICIs. Patients with little or no PD-L1 expression experienced a diminished therapeutic benefit from ICIs.

The tremendous clinical potential of the microbiota in the treatment of breast cancer: the next frontier

Although significant advances have been made in the diagnosis and treatment of breast cancer (BC) in recent years, BC remains the most common cancer in women and one of the main causes of death among women worldwide. Currently, more than half of BC patients have no known risk factors, emphasizing the significance of identifying more tumor-related factors. Therefore, we urgently need to find new therapeutic strategies to improve prognosis. Increasing evidence demonstrates that the microbiota is present in a wider range of cancers beyond colorectal cancer. BC and breast tissues also have different types of microbiotas that play a key role in carcinogenesis and in modulating the efficacy of anticancer treatment, for instance, chemotherapy, radiotherapy, and immunotherapy. In recent years, studies have confirmed that the microbiota can be an important factor directly and/or indirectly affecting the occurrence, metastasis and treatment of BC by regulating different biological processes, such as estrogen metabolism, DNA damage, and bacterial metabolite production. Here, we review the different microbiota-focused studies associated with BC and explore the mechanisms of action of the microbiota in BC initiation and metastasis and its application in various therapeutic strategies. We found that the microbiota has vital clinical value in the diagnosis and treatment of BC and could be used as a biomarker for prognosis prediction. Therefore, modulation of the gut microbiota and its metabolites might be a potential target for prevention or therapy in BC.

Comparative efficacy and safety of first-line neoadjuvant treatments in triple-negative breast cancer: systematic review and network meta-analysis

Neoadjuvant treatment options for triple-negative breast cancer (TNBC) are abundant, but the efficacy of different combinations of treatment options remains unclear. Our network meta-analysis aimed to evaluate the effectiveness and safety of various neoadjuvant treatment options in patients with TNBC. Literature reports published before March 31, 2022, were retrieved from the PubMed, Embase, Cochrane Library, main oncology conference of the European Society of Medical Oncology, American Society of Clinical Oncology, and San Antonio Breast Cancer Symposium databases. Pairwise and Bayesian network meta-analyses were performed to compare direct and indirect evidence, respectively. The primary outcome was pathological complete response (pCR). Comparison of efficiency between different treatment regimens was made by HRs and 95% confidence intervals (CIs). Overall, 26 studies, including 9714 TNBC patients, were assessed in this network meta-analysis. Results indicated that the pCR of immune checkpoint inhibitors plus platinum-containing regimens is better than other joint regimens. PCR rate of neoadjuvant chemotherapy regimens containing bevacizumab, platinum, poly(ADP-ribose) polymerase inhibitors, and immune checkpoint inhibitors was higher than those of standard chemotherapy agents. By performing a conjoint analysis of the pCR rate and safety endpoints, we found that immune checkpoint inhibitors plus platinum-containing regimens were well balanced in terms of efficacy and toxicity. Considering the efficacy and acceptable adverse events, neoadjuvant chemotherapy based on immune checkpoint inhibitors plus platinum may be considered as an option for patients with TNBC.

Combination of FAK inhibitor and cytokine-induced killer cell therapy: An alternative therapeutic strategy for patients with triple-negative breast cancer

Triple-negative breast cancer (TNBC) is characterized by the loss of expression of several biomarkers, which limits treatment strategies for the disease. In recent years, immunotherapy has shown promising results in the treatment of various tumors. Emerging evidence demonstrated that TNBC is an immune-activated cancer, suggesting that immunotherapy could be a feasible treatment option for TNBC. Cytokine-induced killer (CIK) cell therapy is considered as a potential treatment for cancer treatment. However, it is still not approved as a standard treatment in the clinical setting. Our previous study demonstrated that focal adhesion kinase (FAK) plays important role in regulating the sensitivity of TNBC cells to CIK cells. In this study, we further verify the role of FAK in regulating the immune response in vivo. Our in vitro study indicated that knockdown of FAK in TNBC cells or treat with the FAK inhibitor followed by co-culture with CIK cells induced more cell death than CIK cells treatment only. RNA-seq analysis indicated that suppression of FAK could affect several immune-related gene expressions in TNBC cells that affects the immune response in the tumor microenvironment of TNBC cells. The combination of FAK inhibitor and CIK cells significantly suppressed tumor growth than the treatment of FAK inhibitor or CIK cells alone in vivo. Our findings provide new insights into the cytotoxic effect of CIK cell therapy in TNBC treatment and indicate that the combination of CIK cell therapy with FAK inhibitors may be an alternative therapeutic strategy for patients with TNBC.

PD-L1 expression as biomarker of efficacy of PD-1/PD-L1 checkpoint inhibitors in metastatic triple negative breast cancer: A systematic review and meta-analysis

Background

Inhibitors of programmed cell death 1 (PD-1)/programmed cell death ligand 1(PD-L1) checkpoint have been approved for metastatic triple negative breast cancer (mTNBC) in patients positive for PD-L1 expression. Negative results from the recent phase III trials (IMPassion131 and IMPassion132) have raises questions on the efficacy of PD-1/PD-L1 checkpoint inhibitors and the predictive value of PD-L1 expression. Here we attempt to systematically analyze the biomarker value of PD-L1 expression for predicting the response of PD-1/PD-L1 checkpoint inhibitors in mTNBC.

Materials and methods

PubMed database was searched until Dec 2021 for studies evaluating PD-1/PD-L1 checkpoint inhibitors plus/minus chemotherapy in mTNBC. Outcome of interest included objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Review Manager (RevMan) version 5.4. was used for data-analysis.

Results

In total, 20 clinical trials comprising 3962 mTNBC patients (ICT: 2665 (67%); CT: 1297 (33%) were included in this study. Overall ORR was 22% (95%CI, 14-30%) and significant improvement was observed for PD-L1+ patients (ORR 1.78 [95%CI, 1.45-2.19], p<0.00001) as compared to PD-L1- cohort. Pooled outcome also indicated a significant 1-year PFS and 2-year OS advantage for patients with PD-L1 expression (1-year PFS: ORR 1.39 [95%CI, 1.04-1.85], p=0.02; I2 = 0%; 2-year OS: (ORR 2.47 [95%CI, 1.30-4.69], p=0.006; I2 = 63%). Subgroup analysis indicated that PD-L1 expression can successfully predict tumor response and 2-year OS benefit in mTNBC patients regardless of the type of investigating agent, line of treatment administration, and to some extent the type of treatment. Biomarker ability of PD-L1 expression to predict 1-year PFS was slightly better with pembrolizumab (p=0.09) than atezolizumab (p=0.18), and significantly better when treatment was administered in the first-line setting (OR 1.38 [95%CI, 1.02-1.87], p=0.04) and chemotherapy was added (OR 1.38 [95%CI, 1.02-1.86], p=0.03). Immune-related toxicity of any grade and grade≥3 was 39% (95%CI, 26%-52%) and 10% (95%CI, 8%-13%), respectively.

Conclusions

PD-L1 expression can predict objective response rate and 2-year OS in mTNBC patients receiving PD-1/PD-L1 checkpoint inhibitors. One-year PFS is also predicted in selected patients. PD-L1 expression can be a useful biomarker of efficacy of PD-1/PD-L1 checkpoint inhibitors in mTNBC.

Adverse Events of PD-1 or PD-L1 Inhibitors in Triple-Negative Breast Cancer: A Systematic Review and Meta-Analysis

(1) Background: This study aimed to develop a comprehensive understanding of the treatment-related adverse events when using PD-1 or PD-L1 inhibitors in triple-negative breast cancer (TNBC). (2) Methods: We conducted a meta-analysis of Phase II/III randomized clinical trials. Studies were searched for using PubMed, Embase, and Cochrane Library from 1 March 1980 till 30 June 2022. Data on adverse events were mainly extracted from ClinicalTrials.gov and published articles. A generalized linear mixed model with the logit transformation was employed to obtain the overall incidence of adverse events across all studies. For serious adverse events with low incidences, the Peto method was used to calculate the odds ratio (OR) and 95% confidence interval (95%CI) in the PD-1 or PD-L1 inhibitors groups compared to the control groups. (3) Results: Nine studies were included in the meta-analysis, including a total of 2941 TNBC patients treated with PD-1 or PD-L1 inhibitors (including atezolizumab, pembrolizumab and durvalumab) and 2339 patients in the control groups. Chemotherapy alone was the control group in all studies. The average incidences of all serious immune-related adverse events of interest (hypothyroidism, hyperthyroidism, pneumonitis, pruritus, rash) were less than 1%, except for adrenal insufficiency (1.70%, 95%CI: 0.50-5.61%) in the PD-1 or PD-L1 groups. PD-1 or PD-L1 inhibitors significantly increased the risk of serious pneumonitis (OR = 2.52, 95%CI: 1.02-6.26), hypothyroidism (OR = 5.92, 95%CI: 1.22-28.86), alanine aminotransferase (ALT) elevation (OR = 1.66, 95%CI: 1.12-2.45), and adrenal insufficiency (OR = 18.81, 95%CI: 3.42-103.40). For non-serious adverse events, the patients treated with PD-1 or PD-L1 inhibitors had higher risk of aspartate aminotransferase (AST) elevation (OR =1.26, 95%CI: 1.02-1.57), hypothyroidism (OR = 3.63, 95%CI: 2.92-4.51), pruritus (OR = 1.84, 95%CI: 1.30-2.59), rash (OR = 1.29, 95%CI: 1.08-1.55), and fever (OR = 1.77, 95%CI: 1.13-2.77), compared with chemotherapy alone. (4) Conclusions: The incidence of serious immune-related adverse events in PD-1 or PD-L1 inhibitors groups is low but significantly higher than in chemotherapy groups. When using PD-1 or PD-L1 inhibitors for the treatment of TNBC, serious pneumonitis, hypothyroidism, ALT elevation, and adrenal insufficiency should be considered. Non-serious adverse events, such as AST elevation, rash, and fever, should also be taken into consideration.

Combined atezolizumab and nab-paclitaxel in the treatment of triple negative breast cancer: a meta-analysis on their efficacy and safety

BACKGROUND

Triple negative breast cancer (TNBC) is clinically aggressive breast cancer with a poor prognosis. Approximately 20% of TNBC has been found to express programmed death ligand 1 (PD-L1), making it a potential therapeutic target. As a PD-L1 inhibitor, atezolizumab is a recently approved immunotherapeutic drug for TNBC, this meta-analysis (MA) was aimed to review the randomized controlled trial studies (RCTs) of combined atezolizumab and nab-paclitaxel in the treatment of TNBC and synthesize the evidence-based results on its effectiveness and safety.

METHOD

We searched PubMed, Embase, EBSCOhost and ClinicalTrials.gov for the eligible RCTs which compared the efficacy and safety of combined atezolizumab and nab-paclitaxel with nab-paclitaxel alone. The outcomes analyzed included overall survival (OS), progression-free survival (PFS), objective response rate (ORR) and treatment-related adverse effects (AEs).

RESULTS

A total of six RCTs were included in this MA. For efficacy, although OS was not significantly prolonged with combined atezolizumab and nab-paclitaxel (HR 0.90, 95% CI [0.79, 1.01], p=0.08), this combination therapy significantly improved PFS (HR 0.72, 95% CI [0.59, 0.87], p=0.0006) and ORR (RR 1.25, 95% CI [0.79, 1.01] p<0.00001). For safety, any AEs, haematological, gastrointestinal, and liver AEs showed no statistically significant differences between the atezolizumab and nab-paclitaxel combination group and nab-paclitaxel alone group. However, serious AEs, high grade, dermatological, pulmonary, endocrine, and neurological AEs were significantly lower with nab-paclitaxel alone compared to atezolizumab and nab-paclitaxel combined (p-value range from <0.00001 to 0,02).

CONCLUSION

Atezolizumab combined with nab-paclitaxel was associated with improved outcomes in the treatment of TNBC; however, this combination resulted in more toxicity compared to nab-paclitaxel alone. While nab-paclitaxel alone produced chemotherapy-related AEs, the combination of atezolizumab with nab-paclitaxel produced AEs, especially immune-related AEs such as haematological, pulmonary, endocrine, and neurological AEs.

TRIAL REGISTRATION

This research work of systematic review has been registered on PROSPERO (Registration number: CRD42022297952).

Immune Checkpoint Inhibitors and Other Immune Therapies in Breast Cancer: A New Paradigm for Prolonged Adjuvant Immunotherapy

Background: Breast cancer is the most common form of cancer in women worldwide. Advances in the early diagnosis and treatment of cancer in the last decade have progressively decreased the cancer mortality rate, and in recent years, immunotherapy has emerged as a relevant tool against cancer. HER2+ and triple-negative breast cancers (TNBCs) are considered more immunogenic and suitable for this kind of treatment due to the higher rate of tumor-infiltrating lymphocytes (TILs) and programmed death ligand 1 (PD-L1) expression. In TNBC, genetic aberrations further favor immunogenicity due to more neo-antigens in cancer cells. Methods: This review summarizes the principal ongoing conventional and investigational immunotherapies in breast cancer. Particularly, immune checkpoint inhibitors (ICIs) and their use alone or combined with DNA damage repair inhibitors (DDRis) are described. Then, the issue on immunotherapy with monoclonal antibodies against HER-2 family receptors is updated. Other investigational immunotherapies include a new schedule based on the interferon beta-interleukin-2 sequence that was given in ER+ metastatic breast cancer patients concomitant with anti-estrogen therapy, which surprisingly showed promising results. Results: Based on the scientific literature and our own findings, the current evaluation of tumor immunogenicity and the conventional model of adjuvant chemotherapy (CT) are questioned. Conclusions: A novel strategy based on additional prolonged adjuvant immunotherapy combined with hormone therapy or alternated with CT is proposed.

Pancreatic injury following immune checkpoint inhibitors: A systematic review and meta-analysis

Background: Pancreatic injury (pancreatitis, amylase/lipase elevation) is a rare adverse event of immune checkpoint inhibitors (ICIs). With the high number of clinical studies on ICIs, the incidence and characteristics of associated pancreatic injury (PI) need to be reevaluated.

Methods: A systematic review and meta-analysis was conducted to assess the incidence of PI in cancer patients who received ICIs in randomized controlled trials (RCTs). PubMed, Embase, the ASCO, ESMO, and AACR conference proceedings before 1 April 2022, were investigated for relevant research.

Results: 50 RCTs involving 35,223 patients were included. The incidence of ICIs-PI was 2.22% (95% CI = 1.94%–2.53%). The incidence of PI was 3.76% (95% CI = 1.84–7.67%) when combining two ICIs, which was higher than single ICIs [2.25% (95% CI = 1.91–2.65%)]. The ICIs were ranked from high to low based on PI incidence: PD-L1 inhibitors 3.01% (95% CI = 1.86–4.87%), CTLA-4 inhibitors 2.92% (95% CI = 0.99–8.65%) and PD-1 Inhibitor 2% (95% CI = 1.67–2.39%). The ICI with the highest rate of PI was pembrolizumab 7.23.% (95% CI = 1.69–30.89%). In addition, the incidence of severe ICIs-PI was 2.08% (95% CI = 1.76–2.46%); and the incidence of severe PI was 2.32% (95% CI = 1.76–3.06%) when combining two ICIs, which was higher than single ICI [1.95% (95% CI = 1.58–2.41%)]. The ICIs were ranked from high to low according to the incidence of severe PI: PD-L1 inhibitors 3.1% (95% CI = 1.7–5.64%), CTLA-4 inhibitors 2.69% (95% CI = 0.76–9.49%), PD-1 inhibitors 1.80% (95% CI = 1.41–2.29%).

Conclusion: Treatment with multiple ICIs result in a higher incidence of PI compared to single ICIs, irrespective of the grade of pancreatic injury. The incidence of PI caused by PD-L1 inhibitors is higher than that of CTLA-4 inhibitors and PD-1 Inhibitor, and Pembrolizumab has the highest rate of ICIs-PI. Although the incidence of ICIs-PI is not high, they are usually severe (≥ grade 3 events).

In-Silico Drug Toxicity and Interaction Prediction for Plant Complexes Based on Virtual Screening and Text Mining

Potential drug toxicities and drug interactions of redundant compounds of plant complexes may cause unexpected clinical responses or even severe adverse events. On the other hand, super-additivity of drug interactions between natural products and synthetic drugs may be utilized to gain better performance in disease management. Although without enough datasets for prediction model training, based on the SwissSimilarity and PubChem platforms, for the first time, a feasible workflow of prediction of both toxicity and drug interaction of plant complexes was built in this study. The optimal similarity score threshold for toxicity prediction of this system is 0.6171, based on an analysis of 20 different herbal medicines. From the PubChem database, 31 different sections of toxicity information such as "Acute Effects", "NIOSH Toxicity Data", "Interactions", "Hepatotoxicity", "Carcinogenicity", "Symptoms", and "Human Toxicity Values" sections have been retrieved, with dozens of active compounds predicted to exert potential toxicities. In Spatholobus suberectus Dunn (SSD), there are 9 out of 24 active compounds predicted to play synergistic effects on cancer management with various drugs or factors. The synergism between SSD, luteolin and docetaxel in the management of triple-negative breast cancer was proved by the combination index assay, synergy score detection assay, and xenograft model.

Immunotherapy in triple-negative breast cancer: Insights into tumor immune landscape and therapeutic opportunities

Triple-negative breast cancer (TNBC) is a clinically aggressive subtype of breast cancer that represents 15-20% of breast tumors and is more prevalent in young pre-menopausal women. It is the subtype of breast cancers with the highest metastatic potential and recurrence at the first 5 years after diagnosis. In addition, mortality increases when a complete pathological response is not achieved. As TNBC cells lack estrogen, progesterone, and HER2 receptors, patients do not respond well to hormone and anti-HER2 therapies, and conventional chemotherapy remains the standard treatment. Despite efforts to develop targeted therapies, this disease continues to have a high unmet medical need, and there is an urgent demand for customized diagnosis and therapeutics. As immunotherapy is changing the paradigm of anticancer treatment, it arises as an alternative treatment for TNBC patients. TNBC is classified as an immunogenic subtype of breast cancer due to its high levels of tumor mutational burden and presence of immune cell infiltrates. This review addresses the implications of these characteristics for the diagnosis, treatment, and prognosis of the disease. Herein, the role of immune gene signatures and tumor-infiltrating lymphocytes as biomarkers in TNBC is reviewed, identifying their application in patient diagnosis and stratification, as well as predictors of efficacy. The expression of PD-L1 expression is already considered to be predictive of response to checkpoint inhibitor therapy, but the challenges regarding its value as biomarker are described. Moreover, the rationales for different formats of immunotherapy against TNBC currently under clinical research are discussed, and major clinical trials are highlighted. Immune checkpoint inhibitors have demonstrated clinical benefit, particularly in early-stage tumors and when administered in combination with chemotherapy, with several regimens approved by the regulatory authorities. The success of antibody-drug conjugates and research on other emerging approaches, such as vaccines and cell therapies, will also be addressed. These advances give hope on the development of personalized, more effective, and safe treatments, which will improve the survival and quality of life of patients with TNBC.

Rationale and Clinical Research Progress on PD-1/PD-L1-Based Immunotherapy for Metastatic Triple-Negative Breast Cancer

Metastatic triple-negative breast cancer (mTNBC), a highly aggressive and malignant tumor, currently lacks an effective treatment. There has been some progress in the treatment of mTNBC with programmed death receptor-1/programmed death ligand-1 (PD-1/PD-L1) immunotherapy in recent years. The combination of PD-1/PD-L1 inhibitors with other therapies is a noteworthy treatment strategy. Immunotherapy in combination with chemotherapy or small-molecule inhibitors still faces many challenges. Additionally, there are some new immunotherapy targets in development. We aimed to further evaluate the effectiveness and usefulness of immunotherapy for treating mTNBC and to propose new immunotherapy strategies. This review explains the rationale and results of existing clinical trials evaluating PD-1/PD-L1 inhibitors alone or in combination for the treatment of mTNBC. For patients with aggressive tumors and poor health, PD-1/PD-L1 inhibitors, either alone or in combination with other modalities, have proven to be effective. However, more research is needed to explore more effective immunotherapy regimens that will lead to new breakthroughs in the treatment of mTNBC.

Efficacy and safety of PD-1/PD-L1 inhibitors in triple-negative breast cancer: a systematic review and meta-analysis

OBJECTIVE

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with a poor prognosis that seriously threatens women's health. There is still a lack of effective therapeutic targets for TNBC treatment. We conducted a meta-analysis to evaluate the efficacy and safety of programmed cell death protein 1 (PD-1)/programmed death protein ligand 1 (PD-L1) inhibitors in combination with chemotherapy for TNBC patients.

METHODS

We searched PubMed, EMBASE, Cochrane Library, and Web of Science for randomized controlled trials (RCTs) related to PD-1/PD-L1 inhibitors combined with chemotherapy. Literature conforming to the research content was identified according to the inclusion and exclusion criteria. The endpoints of efficacy were pathological complete response (pCR), event-free survival (EFS), progression-free survival (PFS), and overall survival (OS). Safety outcomes included adverse events (AEs) of any grade, AEs of grade ≥3, serious AEs, and the incidence of various AEs. We obtained odds ratios (OR), hazard ratio (HR), and 95% confidence interval (CI) for the included studies. Data analysis was performed using Review Manager software (version 5.3).

RESULTS

A total of 4468 patients from eight RCTs were analyzed. PD-1/PD-L1 inhibitors in combination with chemotherapy significantly improved pCR (OR, 1.59; 95% CI, 1.28 - 1.98, p < 0.0001), EFS (HR, 0.66; 95% CI, 0.48 - 0.91, p = 0.01), and OS (HR, 0.72; 95% CI, 0.52 - 0.99, p = 0.05) in patients with TNBC compared to chemotherapy alone or placebo in combination with chemotherapy. Furthermore, we found that the pCR rate was almost identical in the PD-L1 positive group (OR, 1.65; 95% CI, 1.26 - 2.16, p = 0.0002) and the PD-L1 negative group (OR, 1.56; 95% CI, 1.04 - 2.33, p = 0.03). Among patients with advanced-stage TNBC, PFS (HR, 0.82; 95% CI, 0.74 - 0.90, p < 0.0001) was longer in the combination therapy group than in the chemotherapy group. There were no statistically significant differences between the experimental and control groups in OS (HR, 1.03; 95% CI, 0.74 - 1.42, p = 0.87). In terms of safety, we found that the combination therapy group had a significantly higher incidence of hyperthyroidism in patients with early and advanced TNBC (OR, 5.76; 95% CI, 2.38 - 13.95, p = 0.0001) (OR, 7.86; 95% CI, 2.65 - 23.29, p = 0.0002).

CONCLUSIONS

The combination of PD-1/PD-L1 inhibitors and chemotherapy could improve the survival and prognosis of patients with early and advanced TNBC. Combination treatment may be harmful to the thyroid; therefore, active surveillance and regular follow-up are necessary during treatment.

Research progress on immunotherapy in triple‑negative breast cancer (Review)

Triple‑negative breast cancer (TNBC) is a highly heterogeneous and aggressive malignancy. Due to the absence of estrogen receptors and progesterone receptors and the lack of overexpression of human epidermal growth factor receptor 2, TNBC responds poorly to endocrine and targeted therapies. As a neoadjuvant therapy, chemotherapy is usually the only option for TNBC; however, chemotherapy may induce tumor resistance. The emergence of immunotherapy as an adjuvant therapy is expected to make up for the deficiency of chemotherapy. Most of the research on immunotherapies has been performed on advanced metastatic TNBC, which has provided significant clinical benefits. In the present review, possible immunotherapy targets and ongoing immunotherapy strategies were discussed. In addition, progress in research on immune checkpoint inhibitors in early TNBC was outlined.

New Developments and Opportunities of Microbiota in Treating Breast Cancers

Despite the prevalence of breast cancer (BC), over half of BC cases are unrelated to known risk factors, which highlights the importance of uncovering more cancer-related factors. Currently, the microbiota has been proven to be a potent modulator of the tumor environment in BC, which regulates the immune balance in tumor-related networks. Through a large amount of data accumulation, the microbiota has shown many possibilities to reveal more insights into the development or control of BC. To expand the potential benefits of patients with BC, this study discusses the distribution profile and the effect mechanism of BC-related microbiota on tumors and further discusses its impact on different tumor therapies. Finally, we summarize the possibility of targeting microbiological therapies to improve BC treatment or in combination with other therapies.

Simultaneous glutamine metabolism and PD-L1 inhibition to enhance suppression of triple-negative breast cancer

Blockade of programmed cell death 1 ligand (PD-L1) has been used to treat triple-negative breast cancer (TNBC), and various strategies are under investigation to improve the treatment response rate. Inhibition of glutamine metabolism can reduce the massive consumption of glutamine by tumor cells and meet the demand for glutamine by lymphocytes in tumors, thereby improving the anti-tumor effect on the PD-L1 blockade therapy. Here, molybdenum disulfide (MoS2) was employed to simultaneously deliver anti-PDL1 antibody (aPDL1) and V9302 to boost the anti-tumor immune response in TNBC cells. The characterization results show that MoS2 has a dispersed lamellar structure with a size of about 181 nm and a size of 232 nm after poly (L-lysine) (PLL) modification, with high stability and biocompatibility. The loading capacity of aPDL1 and V9302 are 3.84% and 24.76%, respectively. V9302 loaded MoS2 (MoS2-V9302) can effectively kill 4T1 cells and significantly reduce glutamine uptake of tumor cells. It slightly increases CD8+ cells in the tumor and promotes CD8+ cells from the tumor edge into the tumor core. In vivo studies demonstrate that the combination of aPDL1 and V9302 (MoS2-aPDL1-V9302) can strongly inhibit the growth of TNBC 4T1 tumors. Interestingly, after the treatment of MoS2-aPDL1-V9302, glutamine levels in tumor interstitial fluid increased. Subsequently, subtypes of cytotoxic T cells (CD8+) in the tumors were analyzed according to two markers of T cell activation, CD69, and CD25, and the results reveal a marked increase in the proportion of activated T cells. The levels of cytokines in the corresponding tumor interstitial fluid are also significantly increased. Additionally, during the treatment, the body weights of the mice remain stable, the main indicators of liver and kidney function in the blood do not increase significantly, and there are no obvious lesions in the main organs, indicating low systemic toxicity. In conclusion, our study provides new insights into glutamine metabolism in the tumor microenvironment affects immune checkpoint blockade therapy in TNBC, and highlights the potential clinical implications of combining glutamine metabolism inhibition with immune checkpoint blockade in the treatment of TNBC.

Immunotherapy in Breast Cancer: When, How, and What Challenges?

Breast Cancer (BC) is the second most frequent cause of cancer death among women worldwide and, although there have been significant advances in BC therapies, a significant percentage of patients develop metastasis and disease recurrence. Since BC was demonstrated to be an immunogenic tumor, immunotherapy has broken through as a significant therapy strategy against BC. Over the years, immunotherapy has improved the survival rate of HER2+ BC patients due to the approval of some monoclonal antibodies (mAbs) such as Trastuzumab, Pertuzumab and, recently, Margetuximab, along with the antibody-drug conjugates (ADC) Trastuzumab-Emtansine (T-DM1) and Trastuzumab Deruxtecan. Immune checkpoint inhibitors (ICI) showed promising efficacy in triple-negative breast cancer (TNBC) treatment, namely Atezolizumab and Pembrolizumab. Despite the success of immunotherapy, some patients do not respond to immunotherapy or those who respond to the treatment relapse or progress. The main causes of these adverse events are the complex, intrinsic or extrinsic resistance mechanisms. In this review, we address the different immunotherapy approaches approved for BC and some of the mechanisms responsible for resistance to immunotherapy.

PD-L1/PD-1 and CTLA-4 Expression in Equine Penile Squamous Cell Carcinomas

In horses, penile squamous cell carcinomas (epSCCs) are among the most common cutaneous neoplastic lesions. These tumors usually arise in benign lesions such as viral plaques and papillomas frequently induced by Equus caballus papillomavirus type 2 (EcPV2) infection. In the last decade, the introduction of immune checkpoint inhibitors (ICI) for the treatment of human cancers has demonstrated promising results. Among the most commonly targeted pathways, there is PD-1/PD-L1 and CTLA-4. The aim of this study is to investigate the expression of the PD-1/PD-L1 pathway and CTLA-4 in the tumor microenvironment of epSCCs to assess the feasibility of an immunotherapeutic approach. Twenty equine epithelial tumors were retrospectively selected and submitted to RT-qPCR for PD-1 and PD-L1 genes. After testing antibodies cross-reactivity by western blotting, immunohistochemistry for PD-L1 and CTLA-4 was performed. Results from RT-qPCR demonstrated that 3/20 cases expressed the PD-L1 gene, whereas the PD-1 gene was not detected. Immunohistochemical positivity for PD-L1 was found only in one case. CTLA-4-positive cells were observe in all cases but were few (Mdn = 4.8; IQR = 2.3-7.1 cells/HPF). In this study group, PD-1/PD-L1 and CTLA-4 do not appear to be highly expressed and therefore the use of ICI in epSCCs may not have promising rates of response.

Adverse events associated with immune checkpoint inhibitors in patients with breast cancer: A systematic review and meta-analysis

BACKGROUND

Breast cancer is one of the most prevalent cancers with a high rate of mortality. Immune checkpoint inhibitors (ICIs) have shown promising results in breast cancer treatment. However, the incidences of adverse events (AEs) and immune-related AEs (irAEs) due to ICIs have not been investigated comprehensively. We aimed to determine any-grade and grade 3-5 AEs and irAEs of ICIs compared to the control group which were other conventional therapies in adults with breast cancer.

METHODS

We included controlled clinical trials that involved ICIs in adults with breast cancer to assess AEs and irAEs of ICIs. We systematically searched PubMed, EMBASE, Scopus, Web of Science, the Cochrane Central Register of Controlled Trials, Clinical-Trials.gov, and metaRegister of Controlled Trials up to March 12, 2021. Version 2 of the Cochrane risk-of-bias tool for randomized trials (RoB 2) was used for quality assessment.

RESULTS

Nine studies, including 4687 participants met our inclusion criteria. Rash and infusion reaction were the two most frequent irAEs of any-grade and grade 3-5. Among irAEs, hyperthyroidism had the most prominent difference between the two groups in favor of ICIs followed by hypothyroidism and adrenal insufficiency. Among grade 3-5 and any-grade non-immune AEs, increased aspartate aminotransferase (RR = 1.91; 95% CI, 1.11-3.28) and cough (RR = 1.32; 95%CI, 1.11-1.57) had the highest RRs in favor of ICIs, respectively. The frequencies of overall any-grade and grade 3-5 irAEs were higher in the ICI group.

CONCLUSION

The results showed that all the AEs and irAEs of all the categories were more prevalent with ICIs.