Comparisons of Underlying Mechanisms, Clinical Efficacy and Safety Between Anti-PD-1 and Anti-PD-L1 Immunotherapy: The State-of-the-Art Review and Future Perspectives

Determinants of radiation dose to immune cells during breast radiotherapy

BACKGROUND

The immune system has been identified as an organ at risk in esophageal and lung cancers. However, the dosimetric impact of radiotherapy on immune system exposure in patients treated for breast cancer has never been studied.

METHODS

A monocentric retrospective dosimetric study included 163 patients treated at the Institut Curie (Paris, France) between 2010 and 2016 with locoregional helical tomotherapy after conservative surgery or total mastectomy. The effective dose to the immune system (EDIC) was calculated based on diverse dosimetric parameters. The clinical and volumetric determinants of EDIC in adjuvant radiotherapy of breast cancer were analyzed.

RESULTS

The median EDIC for the population was 4.23 Gy, ranging from 1.82 to 6.19 Gy. Right-sided radiotherapy and regional lymph node irradiation were associated with significantly higher EDIC in univariate (4.38 Gy vs. 3.94 Gy, p < 0.01, and 4.27 Gy vs. 3.44 Gy, p < 0.01, respectively) and multivariate analyses (p < 0.01 and p < 0.01). Liver overexposure was the main contributor to EDIC increase in right-sided breast cancer patients (+0.38 Gy [95%CI: +0.30; +0.46]), while the integral total dose increase was the main contributor to EDIC increase in cases of regional node irradiation (+0.63 Gy [95%CI: +0.42; +0.85]).

CONCLUSION

The EDIC score during adjuvant radiotherapy after breast cancer was statistically significantly higher in the case of right-sided radiotherapy and regional lymph node irradiation. Liver irradiation is the main contributor to immune system exposure in adjuvant irradiation of right-sided breast cancer. Populations in which an association between EDIC and survival would exist have yet to be identified but could potentially include patients treated for triple-negative breast cancer with a poor response to neoadjuvant chemoimmunotherapy.

Dostarlimab: From preclinical investigation to drug approval and future directions

Immune checkpoint blockers (ICB) act by reverting the immunosuppressive phenotype of cancer cells, thus allowing host immune system to generate an immune response to the tumor. One of the key mechanisms targeted by ICB is the PD-1/PD-L1 axis, which lies onto the interaction between the programmed-cell death protein 1 and its ligand, overexpressed in several tumor types. This interaction leads to the inhibition of T-cell proliferation and their apoptosis and exhaustion. Anti-PD-1/PD-L1 monoclonal antibodies are now the mainstay of treatment for several advanced stage tumors. Dostarlimab is a novel IgG4 anti-PD-1 antibody which has yielded remarkable results in mismatch-repair deficient endometrial cancer and locally advanced rectal cancer. This product review will illustrate the preclinical development of dostarlimab and its pharmacological characteristics, the clinical trials published so far and the ongoing clinical investigations.

Real-World Comparative Effectiveness of Nivolumab versus Pembrolizumab in Patients with Unresectable Hepatocellular Carcinoma

PURPOSE

Immune checkpoint inhibitors are effective therapies for advanced hepatocellular carcinoma (HCC); however, comparisons of the clinical efficacy and safety profile for these drugs are still scarce. Thus, the aims of this study were to investigate the differences in efficacy and safety between nivolumab and pembrolizumab in unresectable HCC patients in a real-world setting.

PATIENTS AND METHODS

A total of 115 patients who received treatment with nivolumab (n = 73) or pembrolizumab (n = 42) in combination with or without tyrosine kinase inhibitors was enrolled. Therapeutic response, survival outcomes, and safety profiles were compared among these groups. Multivariate analysis of survival response was performed using Cox proportional hazards regression.

RESULTS

Patients treated with pembrolizumab demonstrated a significantly higher objective response rate than those with nivolumab (38.1% vs. 15.1%; odds ratio 4.18, p = 0.005) regardless of the combination strategies. In addition, pembrolizumab performed a better overall survival (OS) than nivolumab, (34.9 vs. 9.5 months; hazard ratio (HR) = 0.39, p = 0.004). In subgroup analysis, pembrolizumab exhibited favorable OS than nivolumab for monotherapy (HR = 0.16, p = 0.001) or combination therapy (HR = 0.33, p = 0.006) as second-line or later-line (HR = 0.19, p = 0.001) therapy and those with (HR = 0.31, p = 0.006) or without (HR = 0.15, p = 0.004) well-compensated liver disease. The incidence of adverse events was comparable for both treatments.

CONCLUSION

Both pembrolizumab and nivolumab had significant effects for HCC therapy, and pembrolizumab had a significant survival benefit as compared with nivolumab.

Immune checkpoint inhibitors plus capecitabine and oxaliplatin in unresectable or advanced biliary tract cancer patients: A retrospective study

Objective

Immune checkpoint inhibitors (ICIs) have recently been increasingly used in cancer treatment, whereas their clinical application in biliary tract cancer (BTC) patients is uncommon. This study aimed to evaluate the efficacy and safety of ICIs plus capecitabine and oxaliplatin (CAPOX) in the treatment of BTC patients.

Methods

This retrospective study reviewed 26 unresectable or advanced BTC patients who received ICIs plus CAPOX. The treatment continued until disease progression, uncontrollable adverse event (AE) occurrence, intolerable toxicity occurrence, or voluntary withdrawal.

Results

The median treatment cycles were 5.5 [interquartile range (IQR): 3.8–8.0]. Complete response, partial response, stable disease, and progressive disease rates were 0.0%, 46.2%, 23.1%, and 30.8%, respectively. Objective response rate (ORR) and disease control rate (DCR) were 46.2% and 69.2%, correspondingly. Regarding survival, the median progression-free survival (PFS) and overall survival (OS) were 6.1 (95% CI: 4.4–7.7) months and 16.5 (95% CI: 5.0–28.0) months; moreover, the 1-year PFS and OS rates were 21.5% and 54.3%, respectively. An Eastern Cooperative Oncology Group (ECOG) score of 1–3 (vs. 0) was associated with declined DCR, PFS, and OS (all p < 0.050). The most common AEs of ICIs plus CAPOX were thrombocytopenia (61.5%), neutropenia (26.9%), and reactive cutaneous capillary endothelial proliferation (RCCEP) (23.1%). Moreover, 13 (50.0%) patients suffered from grade 3–4 AEs, including thrombocytopenia (50.0%), neutropenia (7.7%), liver dysfunction (7.7%), and RCCEP (3.8%). Notably, the majority of AEs were controllable.

Conclusion

ICIs plus CAPOX chemotherapy exhibit a good efficacy and a manageable safety profile in the treatment of patients with unresectable or advanced BTC.

Population pharmacokinetic models of anti-PD-1 mAbs in patients with multiple tumor types: A systematic review

Aims and background

A number of population pharmacokinetic (PPK) models of anti-programmed cell death-1 (PD-1) monoclonal antibodies (mAbs) in multiple tumor types have been published to characterize the influencing factors of their pharmacokinetics. This review described PPK models of anti-PD-1 mAbs that investigate the magnitude and types of covariate effects in PK parameters, provide a reference for building PPK models of other anti-PD-1 mAbs, and identify areas requiring additional research to facilitate the application of PPK models.

Methods

A systematic search for analyses of PPK models of eleven anti-PD-1 mAbs on the market that were carried out in humans was conducted using PubMed, Embase, and the Cochrane Library. The search covered the period from the inception of the databases to April 2022.

Results

Currently, there are fourteen analyses on PPK models of anti-PD-1 mAbs summarized in this review, including seven models that refer to nivolumab, four referring to pembrolizumab, one referring to cemiplimab, one referring to camrelizumab, and one referred to dostarlimab. Most analyses described the pharmacokinetics of anti-PD-1 mAbs with a two-compartment model with time-varying clearance (CL) and a sigmoidal maximum effect. The estimated CL and volume of distribution in the central (V_C) ranged from 0.179 to 0.290 L/day and 2.98 to 4.46 L, respectively. The median (range) of interindividual variability (IIV) for CL and V_C was 30.9% (8.7%–50.8%) and 29.0% (4.32%–40.7%), respectively. The commonly identified significant covariates were body weight (BW) on CL and V_C, and albumin (ALB), tumor type, sex, and performance status (PS) on CL. Other less assessed significant covariates included lactate dehydrogenase (LDH), immunoglobulin G (IgG), ipilimumab coadministration (IPICO) on CL, and body mass index (BMI), malignant pleural mesothelioma (MESO) on V_C.

Conclusion

This review provides detailed information about the characteristics of PPK models of anti-PD-1 mAbs, the effects of covariates on PK parameters, and the current status of the application of the models. ALB, BW, specific tumor type, sex, and PS should be considered for the future development of the PPK model of anti-PD-1 mAbs. Other potential covariates that were assessed less frequently but still have significance (e.g., LDH, IgG, and IPICO) should not be ignored. Thus, further research and thorough investigation are needed to assess new or potential covariates, which will pave the way for personalized anti-PD-1 mAbs therapy.

PD-L1+ neutrophils as novel biomarkers for stage IV melanoma patients treated with nivolumab

Melanoma displays a rising incidence, and the mortality associated with metastatic form remains high. Monoclonal antibodies that block programmed death (PD-1) and PD Ligand 1 (PD-L1) network have revolutionized the history of metastatic disease. PD-L1 is expressed on several immune cells and can be also expressed on human neutrophils (PMNs). The role of peripheral blood PMNs as predictive biomarkers in anti-PD-1 therapy of melanoma is largely unknown. In this study, we aimed to determine activation status and PD-L1 expression on human neutrophils as possible novel biomarkers in stage IV melanoma patients (MPs). We found that PMNs from MPs displayed an activated phenotype and increased PD-L1 levels compared to healthy controls (HCs). Patients with lower PD-L1⁺ PMN frequencies displayed better progression-free survival (PFS) and overall survival (OS) compared to patients with high PD-L1⁺ PMN frequencies. Multivariate analysis showed that PD-L1⁺ PMNs predicted patient outcome in BRAF wild type MP subgroup but not in BRAF mutated MPs. PD-L1⁺ PMN frequency emerges as a novel biomarker in stage IV BRAF wild type MPs undergoing anti-PD-1 immunotherapy. Our findings suggest further evaluation of the role of neutrophil subsets and their mediators in melanoma patients undergoing immunotherapy.

Real-World Analysis of Nivolumab and Atezolizumab Efficacy in Previously Treated Patients with Advanced Non-Small Cell Lung Cancer

Nivolumab (anti-PD-1 antibody) and atezolizumab (anti-PD-L1 antibody) have shown superior survival outcomes and improved adverse effects compared to standard chemotherapy in advanced non-small cell lung cancer (NSCLC) patients. However, the efficacy of both treatments has not been directly compared in clinical trials. This retrospective, single-centre study was performed from June 2015 to December 2020 and included a cohort of 158 previously treated patients with stage IV or recurrent NSCLC who received PD-1 (nivolumab) (n = 89) or PD-L1 (atezolizumab) (n = 69) inhibitors at the Virgen del Rocío Hospital in Seville. The objective response rate (ORR) was 22.5% in the nivolumab group and 14.5% in the atezolizumab group (p = 0.140). Multivariate analysis did not show significant differences between the two groups for PFS and OS (PFS hazard ratio (HR): 0.80, 95% confidence interval (CI): 0.55−1.17, p = 0.260; OS HR: 0.79, 95% CI: 0.52−1.21, p = 0.281). Adverse events of all grades occurred in 68 patients in the nivolumab group (76.4%) and in 34 patients in the atezolizumab group (49.3%) (p < 0.001). Atezolizumab and nivolumab did not show statistically significant differences in survival outcomes in patients with NSCLC, even when stratified by histological subtype (squamous versus nonsquamous). However, the safety analysis suggested a more favourable toxicity profile for atezolizumab.

Tumor-Associated Macrophages: Key Players in Triple-Negative Breast Cancer

Triple negative breast cancer (TNBC) refers to the subtype of breast cancer which is negative for ER, PR, and HER-2 receptors. Tumor-associated macrophages (TAMs) refer to the leukocyte infiltrating tumor, derived from circulating blood mononuclear cells and differentiating into macrophages after exuding tissues. TAMs are divided into typical activated M1 subtype and alternately activated M2 subtype, which have different expressions of receptors, cytokines and chemokines. M1 is characterized by expressing a large amount of inducible nitric oxide synthase and TNF-α, and exert anti-tumor activity by promoting pro-inflammatory and immune responses. M2 usually expresses Arginase 1 and high levels of cytokines, growth factors and proteases to support their carcinogenic function. Recent studies demonstrate that TAMs participate in the process of TNBC from occurrence to metastasis, and might serve as potential biomarkers for prognosis prediction.