SBRT combined with PD-1/PD-L1 inhibitors in NSCLC treatment: a focus on the mechanisms, advances, and future challenges

Evolving landscape of treatments targeting the microenvironment of liver metastases in non-small cell lung cancer

ABSTRACT

Liver metastases (LMs) are common in lung cancer. Despite substantial advances in diagnosis and treatment, the survival rate of patients with LM remains low as the immune-suppressive microenvironment of the liver allows tumor cells to evade the immune system. The impact of LMs on the outcomes of immune checkpoint inhibitors in patients with solid tumors has been the main focus of recent translational and clinical research. Growing evidence indicates that the hepatic microenvironment delivers paracrine and autocrine signals from non-parenchymal and parenchymal cells. Overall, these microenvironments create pre- and post-metastatic conditions for the progression of LMs. Herein, we reviewed the epidemiology, physiology, pathology and immunology, of LMs associated with non-small cell lung cancer and the role and potential targets of the liver microenvironment in LM in each phase of metastasis. Additionally, we reviewed the current treatment strategies and challenges that should be overcome in preclinical and clinical investigations. These approaches target liver elements as the basis for future clinical trials, including combinatorial interventions reported to resolve hepatic immune suppression, such as immunotherapy plus chemotherapy, immunotherapy plus radiotherapy, immunotherapy plus anti-angiogenesis therapy, and surgical resection.

Immunoradiotherapy for NSCLC: mechanisms, clinical outcomes, and future directions

Non-small-cell lung cancer (NSCLC) has an extremely low 5-year survival rate, with the only effective treatment being immunoradiotherapy (iRT). Here, we review the progress of clinical research on iRT for non-small-cell lung cancer (NSCLC) over 2018-2023, as well as the future directions. We first discuss the synergistic mechanisms of iRT, reflected in three aspects: immune regulation of RT, RT-activated immune-related pathways, and RT-related immune sensitization. iRT may include either external-beam or stereotactic-body RT combined with either immune checkpoint inhibitors (e.g., immunoglobulins against immune programmed cell death (PD) 1/PD ligand 1 or CD8+ T lymphocyte antigen 4) or traditional Chinese medicine drugs. Regarding clinical effectiveness and safety, iRT increases overall and progression-free survival and tumor control rate among patients with NSCLC but without a considerable increase in toxicity risk. We finally discuss iRT challenges and future directions reported over 2018-2023.

Achieving complete metabolic response in stage IV lung adenocarcinoma with chemotherapy, nivolumab, ipilimumab, and salvage SBRT: A case report

Oncogene-negative, PDL1-negative metastatic non-small cell lung cancer (NSCLC) presents significant treatment challenges due to its complexity and resistance to conventional therapies. The case report presented addresses a 55-year-old male patient with oncogene-negative, PDL1-negative stage IV lung adenocarcinoma, showcasing an exceptional complete metabolic response to a multimodality treatment combining double immune checkpoint inhibition (ICI) and chemotherapy, followed by salvage stereotactic body radiotherapy (SBRT). The patient underwent a treatment regimen incorporating two cycles of carboplatin, pemetrexed, nivolumab, and ipilimumab followed by nivolumab, and ipilimumab maintenance. After a partial response, SBRT was applied to persistent lesions, achieving a complete metabolic response. This case highlights the potential of combining dual ICI with chemotherapy and SBRT in treating oncogene-negative, PDL1-negative NSCLC underscoring the importance of multimodality treatment strategies.

Durable complete response to PET-CT driven stereotactic radiation therapy plus pembrolizumab for pleomorphic Pancoast cancer: Case report and literature review

PET-driven SBRT plus pembrolizumab as first-line therapy against pleomorphic Pancoast cancer appears beneficial, probably due to high equivalent doses of SBRT on photopenic necrotic core and synergic immune system stimulation of immunoradiotherapy.

Stereotactic body radiotherapy in lung cancer: a contemporary review

The treatment of early stage non-small cell lung cancer (NSCLC) has improved enormously in the last two decades. Although surgery is not the only choice, lobectomy is still the gold standard treatment type for operable patients. For inoperable patients stereotactic body radiotherapy (SBRT) should be offered, reaching very high local control and overall survival rates. With SBRT we can precisely irradiate small, well-defined lesions with high doses. To select the appropriate fractionation schedule it is important to determine the size, localization and extent of the lung tumor. The introduction of novel and further developed planning (contouring guidelines, diagnostic image application, planning systems) and delivery techniques (motion management, image guided radiotherapy) led to lower rates of side effects and more conformal target volume coverage. The purpose of this study is to summarize the current developments, randomised studies, guidelines about lung SBRT, with emphasis on the possibility of increasing local control and overall rates in "fit," operable patients as well, so SBRT would be eligible in place of surgery.

Immune modulatory roles of radioimmunotherapy: biological principles and clinical prospects

Radiation therapy (RT) not only can directly kill tumor cells by causing DNA double-strand break, but also exerts anti-tumor effects through modulating local and systemic immune responses. The immunomodulatory effects of RT are generally considered as a double-edged sword. On the one hand, RT effectively enhances the immunogenicity of tumor cells, triggers type I interferon response, induces immunogenic cell death to activate immune cell function, increases the release of proinflammatory factors, and reshapes the tumor immune microenvironment, thereby positively promoting anti-tumor immune responses. On the other hand, RT stimulates tumor cells to express immunosuppressive cytokines, upregulates the function of inhibitory immune cells, leads to lymphocytopenia and depletion of immune effector cells, and thus negatively suppresses immune responses. Nonetheless, it is notable that RT has promising abscopal effects and may achieve potent synergistic effects, especially when combined with immunotherapy in the daily clinical practice. This systematic review will provide a comprehensive profile of the latest research progress with respect to the immunomodulatory effects of RT, as well as the abscopal effect of radioimmunotherapy combinations, from the perspective of biological basis and clinical practice.

Multicenter phase II study of moderate low-dose radiotherapy in indolent non-Hodgkin lymphoma: CLCG-iNHL-01 protocol

Background: Radiotherapy is an effective treatment for indolent non-Hodgkin lymphoma (iNHL); however, the optimal radiotherapy dose remains to be determined. We hypothesize that a suitable dose may exist between 4 and 24 Gy. Methods: This prospective multicenter phase II trial intends to recruit 73 sites of iNHL patients, who will receive involved-site radiotherapy of 12 Gy in four fractions. The primary objective is the 6-month clinical complete response rate. Tumor tissue, blood and conjunctival specimens will be collected to identify potential predictive biomarkers. Discussion: The CLCG-iNHL-01 trial will evaluate the efficacy and toxicity of 12 Gy in patients with iNHL and provide information on a novel hypofractionation regimen of low-dose radiotherapy. Clinical Trial Registration: NCT05543070 (ClinicalTrials.gov).

Effects of neoadjuvant stereotactic body radiotherapy plus adebrelimab and chemotherapy for triple-negative breast cancer: A pilot study

Background

Emerging data have supported the immunostimulatory role of radiotherapy, which could exert a synergistic effect with immune checkpoint inhibitors (ICIs). With proven effective but suboptimal effect of ICI and chemotherapy in triple-negative breast cancer (TNBC), we designed a pilot study to explore the efficacy and safety of neoadjuvant stereotactic body radiotherapy (SBRT) plus adebrelimab and chemotherapy in TNBC patients.

Methods

Treatment-naïve TNBC patients received two cycles of intravenous adebrelimab (20 mg/kg, every 3 weeks), and SBRT (24 Gy/3 f, every other day) started at the second cycle, then followed by six cycles of adebrelimab plus nab-paclitaxel (125 mg/m² on days 1 and 8) and carboplatin (area under the curve 6 mg/mL per min on day 1) every 3 weeks. The surgery was performed within 3-5 weeks after the end of neoadjuvant therapy. Primary endpoint was pathological complete response (pCR, ypT0/is ypN0). Secondary endpoints included objective response rate (ORR), residual cancer burden (RCB) 0-I, and safety.

Results

13 patients were enrolled and received at least one dose of therapy. 10 (76.9%) patients completed SBRT and were included in efficacy analysis. 90% (9/10) of patients achieved pCR, both RCB 0-I and ORR reached 100% with three patients achieved complete remission. Adverse events (AEs) of all-grade and grade 3-4 occurred in 92.3% and 53.8%, respectively. One (7.7%) patient had treatment-related serious AEs. No radiation-related dermatitis or death occurred.

Conclusions

Adding SBRT to adebrelimab and neoadjuvant chemotherapy led to a substantial proportion of pCR with acceptable toxicities, supporting further exploration of this combination in TNBC patients.

Funding

None.

Clinical trial number

NCT05132790.

Camouflaged Nanoreactors Mediated Radiotherapy-Adjuvant Chemodynamic Synergistic Therapy

Chemodynamic therapy based on the Fenton-like catalysis ability of Fe3O4 has the advantages of no involvement of chemical drugs and minimal adverse effects as well as the limitation of depletable efficacy. Radiotherapy based on high-energy radiation offers the convenience of treatment and cost-effectiveness but lacks precision and cellular adaptation of tumor cells. Approaching such dilemmas from a nanoscale materials perspective, we aim to bridge the weaknesses of both treatment methods by combining the principles of two therapeutics reciprocally. We have designed a camouflaged Fe3O4@HfO2 composite nanoreactor (FHCM), which combines a chemodynamic therapeutic agent Fe3O4 and a radiosensitizer HfO2 that both has passed clinical trials and was inspired by a cell membrane biomimetic technique. FHCM is employed as conceived radiotherapy-adjuvant chemodynamic synergistic therapy of malignant tumors, which has undergone dual scrutiny from both the physical and biological aspects. Experimental results obtained at different levels, including theory, material characterizations, and in vitro and in vivo verifications, suggest that FHCM effectively impaired tumor cells through physical and molecular biological mechanisms involving a HfO2-Fe3O4 photoelectron-electron transfer chain and DNA damage-ferroptosis-immunity chain. It is worth noting that compared to single therapies such as only chemodynamic therapy or radiotherapy, FHCM-mediated radiotherapy-adjuvant chemodynamic synergistic therapy exhibits stronger tumor inhibition efficacy. It significantly addresses the inherent limitations of chemodynamic therapy and radiotherapy and underscores the feasibility and importance of using existing clinical weapons, such as radiotherapy, as auxiliary strategies to overcome certain flaws of emerging antitumor therapeutics like chemodynamic therapy.

Efficacy and safety of immune checkpoint inhibitors plus recombinant human endostatin therapy as second-line treatment in advanced non-small-cell lung cancer with negative driver gene: a pilot study

Background

Immune checkpoint inhibitors (ICIs) have become the standard second-line treatment for advanced non-small cell lung cancer (NSCLC). Recent findings indicating an intertwined regulation of vascular endothelial growth factor (VEGF) signaling and immunosuppression in the tumor microenvironment suggest that the combination of ICIs and angiogenesis inhibitors could have synergistic antitumor activity, along with favorable tolerability. However, ICIs plus anti-angiogenesis therapy has not been widely evaluated. The purpose of this pilot study was to evaluate the efficacy and safety of ICIs plus recombinant human (rh)-endostatin as second-line treatment in advanced NSCLC with negative driver gene.

Method

Prospectively evaluated the efficacy and safety of ICIs plus rh-endostain as second-line treatment in advanced NSCLC with negative driver gene. The primary endpoints of the study were progression-free survival (PFS) and overall survival (OS). The secondary endpoints were objective response rate (ORR), disease control rate (ORR), and safety.

Results

A total of 34 patients were recruited in this study. 18 patients received ICIs plus anti-angiogenesis therapy (ICIs combination therapy), and 16 patients received ICIs monotherapy. DCR was 88.9% vs 43.8% (P = 0.009). Median PFS (mPFS) was 8.3 months vs. 3.7 months (HR = 0.276, 95% CI 0.125-0.607, P = 0.001). Median OS (mOS) was 18.0 months vs 9.6 months (HR=0.364, 95% CI 0.147-0.902, P=0.009). In multivariate Cox regression analysis, ICI combination therapy prolonged PFS (HR = 0.069, 95% CI 0.019-0.185, P < 0.001) and OS (HR = 0.044, 95% CI 0.011-0.185, P < 0.001). We did not observe a significant difference in the incidence of adverse events (AEs) between the two groups (P > 0.05).

Conclusions

Compared with ICIs monotherapy, ICIs combination therapy improves clinical response in patients with advanced NSCLC with negative driver gene, significantly prolongs PFS and OS, and does not significantly difference the incidence of AEs.

Effect of radiation fractionation on IDO1 via the NF-κB/COX2 axis in non-small cell lung cancer

Radiotherapy (RT) is the mainstay treatment modality for lung cancer. We recently reported that conventionally fractionated radiotherapy (CRT) with daily fractionation of 2Gy significantly increased the activity of indoleamine 2,3-dioxygenase (IDO1), a known immune checkpoint, which predicted poorer long-term survival in patients with non-small cell lung cancer (NSCLC), while stereotactic body radiotherapy (SBRT) using fractionation size of 10Gy did not increase IDO1 activity and had better survival. Here we hypothesized that the hypofractionated SBRT kind of dose fraction stimulates host antitumor immunity via downregulating IDO1 in which CRT could not. We tested this hypothesis in vitro and in vivo using 10Gyx1 and 2Gyx8 fractionations in the laboratory. The results demonstrated that, although there was an initial downregulation after RT, the expression of IDO1 was ultimately upregulated by both fractionation regimens. The 10Gyx1 regimen had minimum upregulation, while the 2Gyx8 regimen significantly increased in IDO1 expression which was positively correlated with the elevated expressions of p-NF-κB and COX2. Pharmacological inhibition of COX2 abolished RT-induced IDO1 expression. Furthermore, the IDO1 inhibitor, D-1-methyl-tryptophan (D-1MT), exerted RT-related tumor-killing effects in the NSCLC cell lines and mouse models. These findings suggest that, in addition to being an immune suppressor, IDO1 may serve as an adaptive resistance factor in RT. Furthermore, an unappreciated mechanism may exist, where a larger fraction size might be superior to conventional sizes in cancer treatment. This study may provide a rationale for future research in using IDO1 as a biomarker to personalize RT dose fractionation and COX2 inhibitor to decrease radiation immune suppression from CRT.

Attenuated Salmonella-delivered PD-1 siRNA enhances the antitumor effects of EZH2 inhibitors in colorectal cancer

Immunotherapy has made significant progress in the treatment of malignant tumors. However, strategies to combine immunotherapy with anticancer drugs have attracted great attention due to the low response rate and unique toxicity profile of immunotherapies and the subsequent development of acquired resistance in some initial responders. EZH2, a histone methyl transferase subunit of a Polycomb repressor complex,is highly expressed in a variety of tumors, and targeting EZH2 has become a new strategy for tumor therapy and drug combination. Here，we studied the effect of EZH2 inhibitors on colorectal cancer cells and their combination with immunotherapy. Our results demonstrated that EZH2 inhibitors can not only significantly inhibit the survival of colorectal cancer (CRC) cells and induce apoptosis, effectively inhibit cell invasion and migration, but also cause an increase in the expression of PD-L1 receptors on the cell surface. To determine the effect of EZH2 in combination with immunotherapy, we combine EZH2 inhibitors with PD-1 siRNA delivered by attenuated Salmonella. The vivo experiments have shown that the combination of EZH2 inhibitors and Salmonella-delivered PD-1 siRNA can further inhibit the development of CRC, trigger effective anti-tumor immunity, and improve therapeutic efficacy. Its underlying mechanisms mainly involve synergistic immunomodulation and apoptosis. This study suggests an emerging strategy based on a combination of EZH2 inhibitor and immunotherapy based on PD-1 inhibition.

CD39 inhibition and VISTA blockade may overcome radiotherapy resistance by targeting exhausted CD8+ T cells and immunosuppressive myeloid cells

Although radiotherapy (RT) has achieved great success in the treatment of non-small cell lung cancer (NSCLC), local relapses still occur and abscopal effects are rarely seen even when it is combined with immune checkpoint blockers (ICBs). Here, we characterize the dynamic changes of tumor-infiltrating immune cells after RT in a therapy-resistant murine tumor model using single-cell transcriptomes and T cell receptor sequencing. At the early stage, the innate and adaptive immune systems are activated. At the late stage, however, the tumor immune microenvironment (TIME) shifts into immunosuppressive properties. Our study reveals that inhibition of CD39 combined with RT preferentially decreases the percentage of exhausted CD8+ T cells. Moreover, we find that the combination of V-domain immunoglobulin suppressor of T cell activation (VISTA) blockade and RT synergistically reduces immunosuppressive myeloid cells. Clinically, high VISTA expression is associated with poor prognosis in patients with NSCLC. Altogether, our data provide deep insight into acquired resistance to RT from an immune perspective and present rational combination strategies.

Efficacy of immune checkpoint inhibitors along with chemotherapy in non-small cell lung cancer and the impact on adverse reactions and serum tumor markers

OBJECTIVE

To examine the efficacy of immune checkpoint inhibitors along with chemotherapy in non-small cell lung cancer (NSCLC) and the effect on adverse reactions and serum tumor markers.

METHODS

Data of 112 NSCLC patients admitted to Geriatric respiratory department, Xi'an International Medical Center Hospital from February 2018 to March 2021 were analyzed retrospectively. Among them, 54 patients treated with concurrent chemotherapy were labeled as the control group (CG), and 58 patients treated with PD-1/PD-L1 inhibitors in addition to chemotherapy were the observation group (OG). The two groups were compared in terms of immune function indexes, therapeutic efficacy, incidence of adverse reactions, 1-year survival rate, serum tumor markers before and after treatment, and independent risk factors affecting patients' prognosis.

RESULTS

Compared to the CG, the OG exhibited significantly better therapeutic efficacy. The levels of IgG, IgA and IgM 6 months after treatment were significantly higher in both groups than those before treatment, and the elevations in the OG were more evident than those in the CG, and the OG demonstrated markedly lower Recombinant Cytokeratin Fragment Antigen 21-1 (CYFRA21-1), Carcinoembryonic antigen (CEA) and Carbohydrate antigen 125 (CA125) levels after treatment than the CG did. Between the two groups, there was no significant difference identified in the incidence of adverse reactions, but the OG was observed to have much higher 1-year survival rate. The pathological stage, differentiation and treatment regimen were independent risk factors affecting patients' prognosis.

CONCLUSION

For NSCLC patients, the adoption of PD-1/PD-L1 inhibitors following chemoradiotherapy shows potential in enhancing clinical efficacy, boosting patients' immune function, and improving long-term survival rates, with premising safety profile.

Radiation combined with ultrasound and microbubbles: A potential novel strategy for cancer treatment

Cancer is one of the leading causes of death worldwide. Several emerging technologies are helping to battle cancer. Cancer therapies have been effective at killing cancer cells, but a large portion of patients still die to this disease every year. As such, more aggressive treatments of primary cancers are employed and have been shown to be capable of saving a greater number of lives. Recent research advances the field of cancer therapy by employing the use of physical methods to alter tumor biology. It uses microbubbles to enhance radiation effect by damaging tumor vasculature followed by tumor cell death. The technique can specifically target tumor volumes by conforming ultrasound fields capable of microbubbles stimulation and localizing it to avoid vascular damage in surrounding tissues. Thus, this new application of ultrasound-stimulated microbubbles (USMB) can be utilized as a novel approach to cancer therapy by inducing vascular disruption resulting in tumor cell death. Using USMB alongside radiation has showed to augment the anti-vascular effect of radiation, resulting in enhanced tumor response. Recent work with nanobubbles has shown vascular permeation into intracellular space, extending the use of this new treatment method to potentially further improve the therapeutic effect of the ultrasound-based therapy. The significant enhancement of localized tumor cell kill means that radiation-based treatments can be made more potent with lower doses of radiation. This technique can manifest a greater impact on radiation oncology practice by increasing treatment effectiveness significantly while reducing normal tissue toxicity. This review article summarizes the past and recent advances in USMB enhancement of radiation treatments. The review mainly focuses on preclinical findings but also highlights some clinical findings that use USMB as a therapeutic modality in cancer therapy.

Bibliometric analysis on the progress of immunotherapy in renal cell carcinoma from 2003-2022

The incidence and mortality rates of renal cell carcinoma (RCC) have been increasing annually due to obesity and environmental pollution. Although immunotherapy of RCC has been studied for decades, few comprehensive bibliometric analyses exist on the treatment. Therefore, the purpose of this bibliometric analysis was to identify scientific achievements of the global research on RCC immunotherapy from 2003 to 2022 and discuss research trends. Data were retrieved from the Clarivate Web of Science Core Collection using a set retrieval strategy. The Bibliometrics tool Cite Space 6.2 R2 (Chaomei Chen, Drexel University) was used to analyze 4,841 articles. The USA had the most publications (n = 1,864); Harvard University was identified as the leading institution (n = 264); and Dr. Toni K. Choueiri, was the most productive researcher in the field (n = 55). Keyword analysis showed that nivolumab, immune checkpoint inhibitors, tumor microenvironment, everolimus, cabozantinib, resistance, pembrolizumab and ipilimumab were the main hotspots and frontier directions of RCC. By analyzing the results of bibliometrics, national and international researchers can better understand the current research status of RCC immunotherapy and identify new directions for future research. However, the analysis also identified pockets of insularity, highlighting a need for greater collaboration and cooperation among researchers to advance the field of RCC immunotherapy.

Long non‑coding RNAs as potential therapeutic targets in non‑small cell lung cancer (Review)

Non‑small cell lung cancer (NSCLC) is one of the most common malignancies with a high morbidity and mortality rate. Long non‑coding RNAs (lncRNAs) have been reported to be closely associated with the occurrence and progression of NSCLC. In addition, lncRNAs have been documented to participate in the development of drug resistance and radiation sensitivity in patients with NSCLC. Due to their extensive functional characterization, high tissue specificity and sex specificity, lncRNAs have been proposed to be novel biomarkers and therapeutic targets for NSCLC. Therefore, in the current review, the functional classification of lncRNAs were presented, whilst the potential roles of lncRNAs in NSCLC were also summarized. Various physiological aspects, including proliferation, invasion and drug resistance, were all discussed. It is anticipated that the present review will provide a perspective on lncRNAs as potential diagnostic molecular biomarkers and therapeutic targets for NSCLC.

Single-cell RNA sequencing reveals enhanced antitumor immunity after combined application of PD-1 inhibitor and Shenmai injection in non-small cell lung cancer

BACKGROUND

Immune checkpoint inhibitors (ICIs) have altered the clinical management of non-small cell lung cancer (NSCLC). However, the low response rate, severe immune-related adverse events (irAEs), and hyperprogressive disease following ICIs monotherapy require attention. Combination therapy may overcome these limitations and traditional Chinese medicine with immunomodulatory effects provides a promising approach. Shenmai injection (SMI) is a clinically effective adjuvant treatment for cancer with chemotherapy and radiotherapy. Therefore, the combined effects and mechanisms of SMI and programmed death-1 (PD-1) inhibitor against NSCLC was focused on this study.

METHODS

A Lewis lung carcinoma mouse model and a lung squamous cell carcinoma humanized mouse model were used to investigate the combined efficacy and safety of SMI and PD-1 inhibitor. The synergistic mechanisms of the combination therapy against NSCLC were explored using single-cell RNA sequencing. Validation experiments were performed using immunofluorescence analysis, in vitro experiment, and bulk transcriptomic datasets.

RESULTS

In both models, combination therapy alleviated tumor growth and prolonged survival without increasing irAEs. The GZMA^high and XCL1^high natural killer (NK) cell subclusters with cytotoxic and chemokine signatures increased in the combination therapy, while malignant cells from combination therapy were mainly in the apoptotic state, suggesting that mediating tumor cell apoptosis through NK cells is the main synergistic mechanisms of combination therapy. In vitro experiment confirmed that combination therapy increased secretion of Granzyme A by NK cells. Moreover, we discovered that PD-1 inhibitor and SMI combination blocked inhibitory receptors on NK and T cells and restores their antitumoral activity in NSCLC better than PD-1 inhibitor monotherapy, and immune and stromal cells exhibited a decrease of angiogenic features and attenuated cancer metabolism reprogramming in microenvironment of combination therapy.

CONCLUSIONS

This study demonstrated that SMI reprograms tumor immune microenvironment mainly by inducing NK cells infiltration and synergizes with PD-1 inhibitor against NSCLC, suggested that targeting NK cells may be an important strategy for combining with ICIs. Video Abstract.

Radiation combined with immune checkpoint inhibitors for unresectable locally advanced non-small cell lung cancer: synergistic mechanisms, current state, challenges, and orientations

Until the advent of immune checkpoint inhibitors (ICIs), definitive radiotherapy (RT) concurrently with chemotherapy was recommended for unresectable, locally advanced non-small cell lung cancer (LA-NSCLC). The trimodality paradigm with consolidation ICIs following definitive concurrent chemoradiotherapy has been the standard of care since the PACIFIC trial. Preclinical evidence has demonstrated the role of RT in the cancer-immune cycle and the synergistic effect of RT combined with ICIs (iRT). However, RT exerts a double-edged effect on immunity and the combination strategy still could be optimized in many areas. In the context of LA-NSCLC, optimized RT modality, choice, timing, and duration of ICIs, care for oncogenic addicted tumors, patient selection, and novel combination strategies require further investigation. Targeting these blind spots, novel approaches are being investigated to cross the borders of PACIFIC. We discussed the development history of iRT and summarized the updated rationale for the synergistic effect. We then summarized the available research data on the efficacy and toxicity of iRT in LA-NSCLC for cross-trial comparisons to eliminate barriers. Progression during and after ICIs consolidation therapy has been regarded as a distinct resistance scenario from primary or secondary resistance to ICIs, the subsequent management of which has also been discussed. Finally, based on unmet needs, we probed into the challenges, strategies, and auspicious orientations to optimize iRT in LA-NSCLC. In this review, we focus on the underlying mechanisms and recent advances of iRT with an emphasis on future challenges and directions that warrant further investigation. Taken together, iRT is a proven and potential strategy in LA-NSCLC, with multiple promising approaches to further improve the efficacy. Video Abstract.

Radiation-induced tumor immune microenvironments and potential targets for combination therapy

As one of the four major means of cancer treatment including surgery, radiotherapy (RT), chemotherapy, immunotherapy, RT can be applied to various cancers as both a radical cancer treatment and an adjuvant treatment before or after surgery. Although RT is an important modality for cancer treatment, the consequential changes caused by RT in the tumor microenvironment (TME) have not yet been fully elucidated. RT-induced damage to cancer cells leads to different outcomes, such as survival, senescence, or death. During RT, alterations in signaling pathways result in changes in the local immune microenvironment. However, some immune cells are immunosuppressive or transform into immunosuppressive phenotypes under specific conditions, leading to the development of radioresistance. Patients who are radioresistant respond poorly to RT and may experience cancer progression. Given that the emergence of radioresistance is inevitable, new radiosensitization treatments are urgently needed. In this review, we discuss the changes in irradiated cancer cells and immune cells in the TME under different RT regimens and describe existing and potential molecules that could be targeted to improve the therapeutic effects of RT. Overall, this review highlights the possibilities of synergistic therapy by building on existing research.

Tackling the current dilemma of immunotherapy in extensive-stage small cell lung cancer: A promising strategy of combining with radiotherapy

Progress in the treatment of small cell lung cancer (SCLC) has been modest over the past decades until the advent of immune checkpoint inhibitors, which have redefined the standard first-line treatment for extensive-stage SCLC (ES-SCLC). However, despite the positive results of several clinical trials, the limited survival benefit achieved suggests that the priming and sustaining of immunotherapeutic efficacy are poor and further investigation is urgently needed. In this review, we aim to summarize the potential mechanisms underlying the limited efficacy of immunotherapy and intrinsic resistance in ES-SCLC, including impaired antigen presentation and limited T cell infiltration. Moreover, to tackle the current dilemma, given the synergistic effects of radiotherapy on immunotherapy, especially the unique advantages of low-dose radiotherapy (LDRT), such as less immunosuppression and lower radiation toxicity, we propose radiotherapy as a booster to enhance the immunotherapeutic efficacy by overcoming the poor priming effect. Recent clinical trials, including ours, have also focused on adding radiotherapy, including LDRT, to first-line treatment of ES-SCLC. Additionally, we also suggest combination strategies to sustain the immunostimulatory effect of radiotherapy, as well as the cancer-immunity cycle, and further improve survival outcomes.

Emerging evidence and treatment paradigm of non-small cell lung cancer

Research on biomarker-driven therapy and immune check-point blockade in non-small cell lung cancer (NSCLC) is rapidly evolving. The width and depth of clinical trials have also dramatically improved in an unprecedented speed. The personalized treatment paradigm evolved every year. In this review, we summarize the promising agents that have shifted the treatment paradigm for NSCLC patients across all stages, including targeted therapy and immunotherapy using checkpoint inhibitors. Based on recent evidence, we propose treatment algorithms for NSCLC and propose several unsolved clinical issues, which are being explored in ongoing clinical trials. The results of these trials are likely to impact future clinical practice.

Optimal timing and sequence of combining stereotactic radiosurgery with immune checkpoint inhibitors in treating brain metastases: clinical evidence and mechanistic basis

Recent evidence has shown that immune checkpoint inhibitors (ICIs) are efficacious for treating brain metastases of various primary tumors. However, the immunosuppressive tumor microenvironment and the blood-brain barrier (BBB) or blood-tumor barrier (BTB) essentially restrict the efficacy of ICIs. Stereotactic radiosurgery (SRS) can be a powerful ally to ICIs due to its trait of disrupting the BBB/BTB and increasing the immunogenicity of brain metastases. The combination of SRS + ICI has shown synergy in brain metastases in several retrospective studies. Nevertheless, the optimal schedule for the combination of SRS and ICI in brain metastases is yet to be determined. In this review, we summarized the current clinical and preclinical evidence on the timing and sequence of SRS + ICI to provide insight into the current state of knowledge about this important area in patient care.

Locally Advanced Lung Cancer

Consolidation immunotherapy after concurrent chemoradiation has improved five-year survival rates in unresectable, locally advanced lung cancer, but disease progression and treatment personalization remain challenges. New treatment approaches with concurrent immunotherapy and consolidative novel agents are being investigated and show promising efficacy data, but at the risk of additive toxicity. Patients with PD-L1 negative tumors, oncogenic driver mutations, intolerable toxicity, or limited performance status continue to require innovative therapies. This review summarizes historical data that galvanized new research efforts, as well as ongoing clinical trials that address the challenges of current therapeutic approaches for unresectable, locally advanced lung cancer.

Clinical impact of first-line PD-1 or PD-L1 inhibitors combined with chemotherapy in extensive-stage small cell lung cancer patients: A real-world multicenter propensity score-matched study

OBJECTIVES

Our research aimed to evaluate the effectiveness of first-line immune checkpoint inhibitors (ICIs) with etoposide and platinum (EP) for extensive-stage small cell lung cancer (ES-SCLC) and identify prognostic factors, as real-world outcomes and the inconsistency of PD-1 and PD-L1 inhibitors are uncertain.

METHODS

We selected ES-SCLC patients in three centers and conducted a propensity score-matched analysis. The Kaplan-Meier method and Cox proportional hazards regression were conducted to compare the survival outcomes. We also performed univariate and multivariate Cox regression analyses to investigate predictors.

RESULTS

Among 236 patients included, 83 pairs of cases were matched. The EP plus ICIs cohort had a longer median overall survival (OS) (17.3 months) than the EP cohort (13.4 months) (hazard ratio [HR],  0.61 [0.45, 0.83]; p = 0.001). The median progression-free survival (PFS) was also longer in the EP plus ICIs cohort (8.3 months) than in the EP cohort (5.9 months) (HR,   0.44 [0.32, 0.60]; p < 0.001). The EP plus ICIs group had a higher objective response rate (ORR) (EP: 62.3%, EP + ICIs: 84.3%, p < 0.001). Multivariate analysis presented that liver metastases (HR, 2.08; p = 0.018) and lymphocyte-monocyte ratio (LMR) (HR, 0.54; p = 0.049) were independent prognostic factors for OS, and performance status (PS) (HR, 2.11; p = 0.015), liver metastases (HR, 2.64; p = 0.002), and neutrophil-lymphocyte ratio (NLR) (HR, 0.45; p = 0.028) were for PFS in patients with chemo-immunotherapy.

CONCLUSION

Our real-world data demonstrated that ICIs with chemotherapy as the first-line setting for ES-SCLC are effective and safe. PS, liver metastases, and inflammatory markers could serve as valuable risk factors.

Effect of Stereotactic Body Radiation Therapy on Diverse Organ Lesions in Advanced Non-Small Cell Lung Cancer Patients Receiving Immune Checkpoint Inhibitors

OBJECTIVE

The combination of stereotactic body radiation therapy (SBRT) and immune checkpoint inhibitors (ICIs) is actively being explored in advanced non-small-cell lung cancer (NSCLC) patients. However, little is known about the optimal fractionation and radiotherapy target lesions in this scenario. This study investigated the effect of SBRT on diverse organ lesions and radiotherapy dose fractionation regimens on the prognosis of advanced NSCLC patients receiving ICIs.

METHODS

The medical records of advanced NSCLC patients consecutively treated with ICIs and SBRT were retrospectively reviewed at our institution from Dec. 2015 to Sep. 2021. Patients were grouped according to radiation sites. Progression-free survival (PFS) and overall survival (OS) were recorded using the Kaplan-Meier method and compared between different treatment groups using the log-rank (Mantel-Cox) test.

RESULTS

A total of 124 advanced NSCLC patients receiving ICIs combined with SBRT were identified in this study. Radiation sites included lung lesions (lung group, n=43), bone metastases (bone group, n=24), and brain metastases (brain group, n=57). Compared with the brain group, the mean PFS (mPFS) in the lung group was significantly prolonged by 13.3 months (8.5 months vs. 21.8 months, HR=0.51, 95%CI: 0.28-0.92, P=0.0195), and that in the bone group prolonged by 9.5 months with a 43% reduction in the risk of disease progression (8.5 months vs. 18.0 months, HR=0.57, 95%CI: 0.29-1.13, P=0.1095). The mPFS in the lung group was prolonged by 3.8 months as compared with that in the bone group. The mean OS (mOS) in the lung and bone groups was longer than that of the brain group, and the risk of death decreased by up to 60% in the lung and bone groups as compared with that of the brain group. When SBRT was concurrently given with ICIs, the mPFS in the lung and brain groups were significantly longer than that of the bone group (29.6 months vs. 16.5 months vs. 12.1 months). When SBRT with 8-12 Gy per fraction was combined with ICIs, the mPFS in the lung group was significantly prolonged as compared with that of the bone and brain groups (25.4 months vs. 15.2 months vs. 12.0 months). Among patients receiving SBRT on lung lesions and brain metastases, the mPFS in the concurrent group was longer than that of the SBRT→ICIs group (29.6 months vs. 11.4 months, P=0.0003 and 12.1 months vs. 8.9 months, P=0.2559). Among patients receiving SBRT with <8 Gy and 8-12 Gy per fraction, the mPFS in the concurrent group was also longer than that of the SBRT→ICIs group (20.1 months vs. 5.3 months, P=0.0033 and 24.0 months vs. 13.4 months, P=0.1311). The disease control rates of the lung, bone, and brain groups were 90.7%, 83.3%, and 70.1%, respectively.

CONCLUSION

The study demonstrated that the addition of SBRT on lung lesions versus bone and brain metastases to ICIs improved the prognosis in advanced NSCLC patients. This improvement was related to the sequence of radiotherapy combined with ICIs and the radiotherapy fractionation regimens. Dose fractionation regimens of 8-12 Gy per fraction and lung lesions as radiotherapy targets might be the appropriate choice for advanced NSCLC patients receiving ICIs combined with SBRT.

Role of sPD-1 and sPD-Ls in the pathogenesis of connective tissue disease

Membrane-bound programmed cell death-1 (mPD-1) and membrane-bound programmed cell death-ligands (mPD-Ls) have soluble forms, which are soluble programmed cell death-1 (sPD-1) and soluble programmed cell death-ligands (sPD-Ls) [including soluble programmed cell death-ligand 1 (sPD-L1) and soluble programmed cell death-ligand 2 (sPD-L2)]. sPD-1 and sPD-L2 are mainly produced by alternative splicing isoforms of PD-1 mRNA, while sPD-L1 is produced by matrix metalloproteinases (MMPs) cutting membrane-bound programmed cell death-ligand 1 (mPD-L1). sPD-1 and sPD-Ls play an important role in autoimmune regulation via blocking the mPD-1 /mPD-L1 pathway, while connective tissue disease (CTD) is a kind of disease caused by autoimmune reaction, and abnormal function of mPD-1/mPD-L1 can occur in the occurrence and development of many autoimmune diseases. Therefore, sPD-1 and sPD-Ls play an important role in the pathogenesis of CTD caused by autoimmune reaction via blocking the mPD-1 /mPD-L1 pathway. It is of great practical significance to understand clinical value of sPD-1 and sPD-Ls in various CTDs for improving the quality of life of patients and the underlying mechanism.

Efficacy and safety of PD1/PDL1 inhibitors combined with radiotherapy and anti-angiogenic therapy for solid tumors: A systematic review and meta-analysis

BACKGROUND

The triple combination of programmed cell death 1 (PD1)/programmed cell death ligand 1 (PDL1) inhibitors, radiotherapy (RT), and anti-angiogenesis agents has been widely used in the treatment of solid tumors and has shown positive efficacy. We conducted a meta-analysis to evaluate the efficacy and safety of PD1/PDL1 inhibitors combined with anti-angiogenic agents and RT for the treatment of solid cancers.

METHODS

A systematic search of PubMed, Embase, Cochrane Library, and Web of Science databases was conducted from inception to October 31, 2022. Studies involving patients with solid cancers who received PD1/PDL1 inhibitors combined with RT and anti-angiogenic agents treatment that reported overall response rate, complete remission rate, disease control rate, and adverse events (AEs) were included. A random-effects or fixed-effects model was used for the pooled rates, and 95% confidence intervals (CIs) were determined for all outcomes. The quality of the included literature was assessed using the methodological index for nonrandomized studies critical appraisal checklist. Egger test was used to assess the publication bias in the included studies.

RESULTS

Ten studies (4 nonrandomized controlled trials and 6 single-arm trials), including 365 patients, were identified and included in the meta-analysis. The pooled overall response rate after treatment with PD1/PDL1 inhibitors combined with RT and anti-angiogenic agents was 59% (95% CI: 48-70%), whereas the disease control rate and complete remission rate were 92% (95% CI: 81-103%) and 48% (95% CI: 35-61%), respectively. Moreover, the meta-analysis showed that compared with triple-regimen, monotherapy or dual-combination treatment did not improve overall survival (hazard ratio = 0.499, 95% CI: 0.399-0.734) and progression-free survival (hazard ratio = 0.522, 95% CI: 0.352-0.774). The pooled rate of grade 3 to 4 AEs was 26.9% (95% CI: 7.8%-45.9), and the common AEs to triple therapy included leukopenia (25%), thrombocytopenia (23.8%), fatigue (23.2%), gastrointestinal discomfort (22%), increased alanine aminotransferase (22%), and neutropenia (21.4%).

CONCLUSION

In the treatment of solid tumors, PD1/PDL1 inhibitors combined with RT and anti-angiogenic drugs achieved a positive response and better survival benefits than monotherapy or dual therapy. In addition, combination therapy is tolerable and safe.

REGISTRATION

PROSPERO ID: CRD42022371433.

Vidutolimod in Combination With Atezolizumab With and Without Radiation Therapy in Patients With Programmed Cell Death Protein 1 or Programmed Death-Ligand 1 Blockade-Resistant Advanced NSCLC

Introduction

Vidutolimod, a CpG-A TLR9 agonist, was investigated in a phase 1b study (CMP-001-003; ClinicalTrials.gov, NCT03438318) in combination with atezolizumab with and without radiation therapy (RT) in patients with advanced NSCLC.

Methods

Patients with progressive disease after anti-programmed cell death protein 1 or programmed death-ligand 1 therapy received either vidutolimod and atezolizumab (part A) or vidutolimod, atezolizumab, and RT (part B). The primary objective was to evaluate the safety of vidutolimod and atezolizumab with and without RT. Key secondary end point was best objective response rate per Response Evaluation Criteria in Solid Tumors, version 1.1.

Results

Between March 28, 2018, and July 25, 2019, a total of 29 patients were enrolled and received at least one dose of vidutolimod (part A, n = 13; part B, n = 16). Intratumoral injections of vidutolimod were administered successfully, including injection of visceral lesions. The most common treatment-related adverse events (≥30%) were flu-like symptoms and hypotension. No objective responses were observed; 23.1% and 50.0% of the patients in parts A and B, respectively, had stable disease as best response. In parts A and B, 15.4% and 25.0% of the patients, respectively, had tumor shrinkage (<30% decrease in tumor size, nonirradiated). Enrollment was stopped owing to lack of objective responses. In the two patients with initial tumor shrinkage in part A, a strong serum induction of C-X-C motif chemokine ligand 10 was observed.

Conclusions

Vidutolimod and atezolizumab with and without RT had a manageable safety profile, with minimal clinical activity in heavily pretreated patients with programmed cell death protein 1 or programmed death-ligand 1 blockade-resistant NSCLC.

The paradoxical role of radiation-induced cGAS-STING signalling network in tumour immunity

The cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway is an essential component of the innate immune system and is central to the identification of abnormal DNA leakage caused by ionising radiation (IR) damage. Cell-intrinsic cGAS-STING initiation has been revealed to have tremendous potential for facilitating interferon synthesis and T-cell priming. Targeting the cGAS-STING axis has been proposed as a strategy to improve radiosensitivity or enhance immunosurveillance. However, due to the complex biology of the irradiated tumour microenvironment and the extensive involvement of the cGAS-STING pathway in various physiological and pathological processes, many defects in this strategy limit the therapeutic effect. Here, we outline the molecular mechanisms by which IR activates the cGAS-STING pathway and analyse the dichotomous roles of the cGAS-STING pathway in modulating cancer immunity after radiotherapy (RT). Then, based on the crosstalk between the cGAS-STING pathway and other signalling events induced by IR, such as necroptosis, autophagy and other cellular effects, we discuss the immunomodulatory actions of the broad cGAS-STING signalling network in RT and their potential therapeutic applications. Finally, recent advances in combination therapeutic strategies targeting cGAS-STING in RT are explored.

Assessing Potential Factors Influencing the Efficacy of Immune Checkpoint Inhibitors with Radiation in Advanced Non-Small-Cell Lung Cancer Patients: A Systematic Review and Meta-Analysis

Objective

Recent evidence suggests that combining radiotherapy (RT) with immune checkpoint inhibitors (ICIs) may result in better outcomes. In this study, we assessed the efficacy and safety of ICI plus radiation versus ICI alone and explored potential factors affecting its efficacy in advanced non-small-cell lung cancer (NSCLC) patients.

Methods

The databases including PubMed and Embase were searched to retrieve eligible studies comparing the efficacy and safety outcomes in advanced NSCLC patients after ICIs ± RT treatments. We performed subgroup analyses to identify potential prognostic factors from radiation details and study types. The odds ratio (OR) of objective response rate (ORR) and disease control rate (DCR), hazard ratio (HR) of progression-free survival (PFS) and overall survival (OS), and risk ratio (RR) of adverse events were used to represent the outcome effects.

Results

26 eligible studies with 14192 cases were included. The results showed that the ORR (OR = 0.63, 95% CI: 0.42, 0.93; p = 0.02) and DCR (OR = 0.55, 95% CI: 0.36, 0.82; p < 0.01) of RT + ICIs groups were significantly higher than those of the ICIs alone group. The median PFS and OS for ICIs versus RT + ICIs were 2.2 versus 4.4 months and 9.0 versus 13.4 months, respectively. Patients in the ICIs plus RT group had a significantly better PFS (HR = 0.72, 95% CI: 0.64, 0.81; p < 0.01) and OS (HR = 0.74, 95% CI: 0.65, 0.83; p < 0.01) when compared to those in the ICIs group. In terms of adverse events, the risk of pneumonia was not significantly increased in patients treated with both ICIs and RT when compared to ICIs group alone (risk ratio = 0.89; 95% CI: 0.55, 1.44; p = 0.63). The correlation analysis found that PFS was significantly correlated with OS (p = 0.02). The subgroup analysis results showed that significant improvements in OS were observed in non-palliative RT group (HR = 0.29, 95% CI: 0.13, 0.65; p < 0.01) and extracranial RT group (HR = 0.70, 95% CI: 0.59, 0.83; p < 0.01). RT type could also be a prognostic factor associated with the OS (for conventional RT: HR = 0.68 and p = 0.22; for stereotactic body radiation therapy: HR = 0.77 and p < 0.01). However, concerning RT timing, the results showed a similar trend in reducing mortality risk (for previous RT: HR = 0.64 and p = 0.21; for concurrent RT: HR = 0.35 and p = 0.16).

Conclusion

RT plus ICIs is associated with improved survival for advanced NSCLC patients, especially for those with non-palliative RT. Further clinical trials are needed to validate its effect on survival outcomes.

Application of individualized multimodal radiotherapy combined with immunotherapy in metastatic tumors

Radiotherapy is one of the mainstays of cancer treatment. More than half of cancer patients receive radiation therapy. In addition to the well-known direct tumoricidal effect, radiotherapy has immunomodulatory properties. When combined with immunotherapy, radiotherapy, especially high-dose radiotherapy (HDRT), exert superior systemic effects on distal and unirradiated tumors, which is called abscopal effect. However, these effects are not always effective for cancer patients. Therefore, many studies have focused on exploring the optimized radiotherapy regimens to further enhance the antitumor immunity of HDRT and reduce its immunosuppressive effect. Several studies have shown that low-dose radiotherapy (LDRT) can effectively reprogram the tumor microenvironment, thereby potentially overcoming the immunosuppressive stroma induced by HDRT. However, bridging the gap between preclinical commitment and effective clinical delivery is challenging. In this review, we summarized the existing studies supporting the combined use of HDRT and LDRT to synergistically enhance antitumor immunity, and provided ideas for the individualized clinical application of multimodal radiotherapy (HDRT+LDRT) combined with immunotherapy.

Abscopal effect triggered by radiation sequential mono-immunotherapy resulted in a complete remission of PMMR sigmoid colon cancer

Background

Radiation therapy combined with immune checkpoint inhibitors (ICIs) has recently turned into an appealing and promising approach to enhance the anti-tumor immunity and efficacy of immunological drugs in many tumors. Abscopal effect induced by radiation is a phenomenon that often leads to an efficient immunity response. In this study, we investigated whether the combination of the immunogenic effects derived from radiotherapy sequential ICIs-based therapy could increase the incidence of abscopal effects, and improve the survival rates.

Case presentation

We described a clinical case regarding a 35-year-old male patient who was admitted to our hospital with a diagnosis of adenocarcinoma of the sigmoid colon and synchronous multiple liver metastases following a surgical resection. The molecular pathological examination showed immune-desert phenotype and proficient mismatch repair (pMMR). The patient was treated with adjuvant chemotherapy after surgery, however, after 7 months, multiple metastasis in the pelvic lymph nodes were diagnosed. Unfortunately, the tumor progressed despite multiple cycles of chemotherapy combined with cetuximab or bevacizumab. Within the follow-up treatment, the patient was administered with only 50Gy/25F of radiation dose to treat the anastomotic lesions. Subsequently, mono-sindilizumab was used as systemic therapy, leading to a rapid reduction of all pelvic lesions and complete clinical remission. So far, the patient survived for more than 20 months under continuous mono-sindilizumab treatment and is still in complete remission.

Conclusion

A localized radiotherapy combined with a sindilizumab-based systemic therapy may overcome the immune resistance of pMMR metastatic colorectal cancer (mCRC), thus obtaining greater efficacy of the therapy. Its mechanism may be related to the abscopal effect obtained by the synergistic use of radiation and sindilizumab, which should be further investigated in the future.

Predictive value of 18F-FDG PET/CT for evaluating the response to hypofractionated radiotherapy combined with PD-1 blockade in non-small cell lung cancer

Purpose

This retrospective study aimed to investigate ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG)-positron emission tomography/computed tomography (PET/CT) as a predictor of response to hypofractionated radiotherapy (HFRT) combined with programmed cell death-1 (PD-1) blockade for lung cancer.

Methods

We included 41 patients with advanced non-small cell lung cancer (NSCLC) in this study. PET/CT was performed before (SCAN-0) and one month (SCAN-1), three months (SCAN-2), and six months (SCAN-3) after treatment. Using the European Organization for Research and Treatment of Cancer 1999 criteria and PET response criteria in solid tumors, treatment responses were classified as complete metabolic response (CMR), partial metabolic response (PMR), stable metabolic disease (SMD), or progressive metabolic disease (PMD). Patients were further categorized as those with metabolic benefits (MB; SMD, PMR, and CMR) and those without MBs (NO-MB; PMD). We analyzed the prognosis and overall survival (OS) of patients with new visceral/bone lesions during treatment. Based on the findings, we generated a nomogram to predict survival. Receiver operating characteristics and calibration curves were used to evaluate the accuracy of the prediction model.

Results

The mean OS based on SCANs 1, 2, and 3 was significantly higher in patients with MB and those without new visceral/bone lesions. The prediction nomogram for survival had a high area under the curve and a high predictive value based on the receiver operating characteristics and calibration curves.

Conclusion

¹⁸FDG-PET/CT has the potential to predict the outcomes of HFRT combined with PD-1 blockade in NSCLC. Therefore, we recommend using a nomogram to predict patient survival.

Safety and feasibility of toripalimab plus lenvatinib with or without radiotherapy in advanced BTC

Background

Toripalimab shows antitumor efficacy in cholangiocarcinoma. Radiotherapy (RT) may enhance systemic responses of PD-1 inhibitors and lenvatinib. This study was designed to assess the safety and feasibility of toripalimab plus lenvatinib with or without RT in advanced BTC.

Methods

This study involved 88 patients with advanced BTC receiving toripalimab plus lenvatinib with or without RT from the clinical trials (NCT03892577). Propensity score matching (PSM) (1:1) analysis was used to balance potential bias. The overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and adverse events (AEs) were evaluated.

Results

After PSM, the final analysis included 40 patients: 20 receiving toripalimab plus lenvatinib without RT (NRT); 20 receiving toripalimab plus lenvatinib with RT. The AEs were more frequent in the RT group than in the NRT group without treatment-associated mortality. The addition of RT did not cause specific AEs. The median PFS was significantly longer with RT (10.8 versus 4.6 months, p<0.001). The median OS was 13.7 months with RT versus 9.2 months in the NRT group (p=0.008). The ORR was 35% (95% CI: 12.1-57.9) in the RT group versus 20% (95% CI: 0.8-39.2) in the NRT group.

Conclusions

The addition of RT may enhance the efficacy of toripalimab plus lenvatinib. Toripalimab plus lenvatinib with RT have a good safety profile without an increase in specific toxicities in advanced BTC patients.

PD-1 inhibitor combined with radiotherapy and GM-CSF in MSS/pMMR metastatic colon cancer: a case report

Patients with chemo-refractory metastatic colorectal cancer (mCRC) have poor prognoses. The application of programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) inhibitors encouragingly improved the survival of mCRC patients with microsatellite instability-high (MSI-H)/mismatch repair-deficient (dMMR). Unfortunately, it was ineffective for mCRC with microsatellite-stable (MSS)/proficient mismatch repair (pMMR), which accounted for 95% of mCRC. Radiotherapy can promote local control by directly killing tumor cells and inducing positive immune activities, which might help synergistically with immunotherapy. We present the report of an advanced MSS/pMMR mCRC patient who had progressive disease (PD) after first-line chemotherapy, palliative surgery and second-line chemotherapy combined with targeted therapy. Then the patient received the therapy of PD-1 inhibitor combined with radiotherapy and granulocyte-macrophage colony-stimulating factor (GM-CSF). According to Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST1.1), the patient showed a complete response (CR) after triple-combined therapy with progression-free survival (PFS) for more than 2 years so far. The patient had no other significant adverse reactions except for fatigue (Grade 1). The triple-combination therapy provided a promising strategy for metastatic chemo-refractory MSS/pMMR mCRC patients.

Anti-TGF-β/PD-L1 bispecific antibody promotes T cell infiltration and exhibits enhanced antitumor activity in triple-negative breast cancer

BACKGROUND

Agents blocking programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) have been approved for triple-negative breast cancer (TNBC). However, the response rate of anti-PD-1/PD-L1 is still unsatisfactory, partly due to immunosuppressive factors such as transforming growth factor-beta (TGF-β). In our previous pilot study, the bispecific antibody targeting TGF-β and murine PD-L1 (termed YM101) showed potent antitumor effect. In this work, we constructed a bispecific antibody targeting TGF-β and human PD-L1 (termed BiTP) and explored the antitumor effect of BiTP in TNBC.

METHODS

BiTP was developed using Check-BODY^TM bispecific platform. The binding affinity of BiTP was measured by surface plasmon resonance, ELISA, and flow cytometry. The bioactivity was assessed by Smad and NFAT luciferase reporter assays, immunofluorescence, western blotting, and superantigen stimulation assays. The antitumor activity of BiTP was explored in humanized epithelial-mesenchymal transition-6-hPDL1 and 4T1-hPDL1 murine TNBC models. Immunohistochemical staining, flow cytometry, and bulk RNA-seq were used to investigate the effect of BiTP on immune cell infiltration.

RESULTS

BiTP exhibited high binding affinity to dual targets. In vitro experiments verified that BiTP effectively counteracted TGF-β-Smad and PD-L1-PD-1-NFAT signaling. In vivo animal experiments demonstrated that BiTP had superior antitumor activity relative to anti-PD-L1 and anti-TGF-β monotherapy. Mechanistically, BiTP decreased collagen deposition, enhanced CD8⁺ T cell penetration, and increased tumor-infiltrating lymphocytes. This improved tumor microenvironment contributed to the potent antitumor activity of BiTP.

CONCLUSION

BiTP retains parent antibodies' binding affinity and bioactivity, with superior antitumor activity to parent antibodies in TNBC. Our data suggest that BiTP might be a promising agent for TNBC treatment.

Improved Tumor Responses with Sequential Targeted α-Particles Followed by Interleukin 2 Immunocytokine Therapies in Treatment of CEA-Positive Breast and Colon Tumors in CEA Transgenic Mice

Targeted α-therapy (TAT) delivers high-linear-transfer-energy α-particles to tumors with the potential to generate tumor immune responses that may be augmented by antigen-targeted immunotherapy. Methods: This concept was evaluated in immunocompetent carcinoembryonic antigen (CEA) transgenic mice bearing CEA-positive mammary or colon tumors. Tumors were targeted with humanized anti-CEA antibody M5A labeled with ²²⁵Ac for its 10-d half-life and emission of 4 α-particles, as well as being targeted with the immunocytokine M5A-interleukin 2. Results: A dose response (3.7, 7.4, and 11.1 kBq) to TAT only, for orthotopic CEA-positive mammary tumors, was observed, with a tumor growth delay of 30 d and an increase in median survival from 20 to 36 d at the highest dose. Immunocytokine (4 times daily) monotherapy gave a tumor growth delay of 20 d that was not improved by addition of 7.4 kBq of TAT 5 d after the start of immunocytokine. However, TAT (7.4 kBq) followed by immunocytokine 10 d later led to a tumor growth delay of 38 d, with an increase in median survival to 45 d. Similar results were seen for TAT followed by immunocytokine at 5 versus 10 d. When a similar study was performed with subcutaneously implanted CEA-positive MC38 colon tumors, TAT (7.4 kBq) monotherapy gave an increase in median survival from 29 to 42 d. The addition of immunocytokine 10 d after 7.4 kBq of TAT increased median survival to 57 d. Immunophenotyping showed increased tumor-infiltrating interferon-γ-positive, CD8-positive T cells and an increased ratio of these cells to Foxp3-positive, CD4-positive regulatory T cells with sequential therapy. Immunohistochemistry confirmed there was an increase in tumor-infiltrating CD8-positive T cells in the sequential therapy group, strongly suggesting that immunocytokine augmented TAT can lead to an immune response that improves tumor therapy. Conclusion: Low-dose (7.4 kBq) TAT followed by a 4-dose immunocytokine regimen 5 or 10 d later gave superior tumor reductions and survival curves compared with either monotherapy in breast and colon cancer tumor models. Reversing the order of therapy to immunocytokine followed by TAT 5 d later was equivalent to either monotherapy in the breast cancer model.

Single-cell analyses reveal the therapeutic effects of ATHENA and its mechanism in a rhabdomyosarcoma patient

Background

Whole-cell tumor vaccines tend to suffer from low immunogenicity. Our previous study showed that irradiated lung cancer cell vaccines in mouse models enhance antitumor efficacy by eliciting an intensive T cells response and improving immunogenicity. Based on these findings, we developed an improved whole-cell tumor vaccine, Autologous Tumor Holo antigEn immuNe Activation (ATHENA).

Methods

In this study, we report the successful treatment of a 6-year-old male diagnosed with meningeal rhabdomyosarcoma with pulmonary and liver metastases using ATHENA. After 6 cycles of therapy, PET/CT showed the therapeutic efficacy of ATHENA. We profiled the immune response by single-cell RNA sequencing (scRNA-seq). Flow cytometry analysis was implemented to validate the status transitions of CD8+ T cells.

Results

In CD8+ T cells, the exhausted status was weakened after treatment. The exhausted CD4+ T cells shifted towards the central memory phenotype after the treatment. Breg cells were converted to Plasma or Follicular B cells. Survival analysis for pan-cancer and transcription factor analysis indicated that such T cell and B cell transitions represent the recovery of antitumoral adaptive immune response. We validated that the proportion of CD279+CD8+ T cells were reduced and the expression of CD44 molecule was upregulated by flow cytometry assay.

Conclusion

Such studies not only show that ATHENA therapy may be a promising alternative treatment for tumor patients but provide a novel idea to analyses the mechanisms of rare cases or personalized cancer treatment.

Identification of Key Genes and FUNCTIONAL Pathway in Radioresistance of Non-Small Cell Lung Cancer

Purpose

For better understanding of radiotherapy resistance and its potential mechanism.

Methods

We established radioresistance cell lines of non-small cell lung cancer (NSCLC) followed by microarray analysis. 529 differentially expressed genes (DEGs) were then screened between radiation resistant cell lines compared with the sensitive cell lines. The biological functions and enrichment pathways of the above DEGs were identified using Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) enrichment analyses. Gene Set Enrichment Analysis (GSEA) revealed that the radiation resistance group had the most gene sets enriched in altered immune response, such as TNF signaling pathway, when compared to the radiation sensitive group. Protein-protein interaction (PPI) network was carried out through the STRING database, and then five hub genes (CXCL10, IFIH1, DDX58, CXCL11, RSAD2) were screened by Cytoscape software. RT-PCR confirmed the expression of the above hub genes. ChIP-X Enrichment Analysis showed that STAT1 might be the transcription factor of the above hub genes. Considering that PD-L1 could be activated by STAT1 in a variety of tumors and ultimately lead to immune exhaustion, RT-PCR and Western blot verified the expression level of PD-L1.

Results

Five hub genes (CXCL10, IFIH1, DDX58, CXCL11, RSAD2) were screened and verified to be highly expressed in radioresistance group, STAT1 might be the transcription factor of the above hub genes. Our study found that the expression level of PD-L1 was increased after radiotherapy resistance.

Conclusion

Although immune system activation occurs followed by radiation resistance, we hypothesized that the upregulation of PD-L1 expression caused by STAT1 activation might be one of the mechanisms of radiotherapy resistance.

Effect of stereotactic radiotherapy on immune microenvironment of lung cancer

Stereotactic radiotherapy (SRT) is one of the main treatment modalities for lung cancer, and the current SRT approach combined with immunotherapy has initially presented good clinical efficacy in lung cancer. SRT activates the immune system through in situ immunization, releasing antigens into the blood, which promotes the antigen–antibody response and then induces tumor cell apoptosis. Dose fractionation has different effects on the immune microenvironment, and the tumor microenvironment after SRT also changes over time, all of which have an impact on SRT combined immunotherapy. Although much research on the immune microenvironment of SRT has been conducted, many problems still require further exploration.

Current insight into the regulation of PD-L1 in cancer

The molecular mechanisms underlying cancer immune escape are a core topic in cancer immunology research. Cancer cells can escape T cell-mediated cellular cytotoxicity by exploiting the inhibitory programmed cell-death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1, CD274) immune checkpoint. Studying the PD-L1 regulatory pattern of tumor cells will help elucidate the molecular mechanisms of tumor immune evasion and improve cancer treatment. Recent studies have found that tumor cells regulate PD-L1 at the transcriptional, post-transcriptional, and post-translational levels and influence the anti-tumor immune response by regulating PD-L1. In this review, we focus on the regulation of PD-L1 in cancer cells and summarize the underlying mechanisms.

Radiotherapy combined with immunotherapy: the dawn of cancer treatment

Radiotherapy (RT) is delivered for purposes of local control, but can also exert systemic effect on remote and non-irradiated tumor deposits, which is called abscopal effect. The view of RT as a simple local treatment has dramatically changed in recent years, and it is now widely accepted that RT can provoke a systemic immune response which gives a strong rationale for the combination of RT and immunotherapy (iRT). Nevertheless, several points remain to be addressed such as the interaction of RT and immune system, the identification of the best schedules for combination with immunotherapy (IO), the expansion of abscopal effect and the mechanism to amplify iRT. To answer these crucial questions, we roundly summarize underlying rationale showing the whole immune landscape in RT and clinical trials to attempt to identify the best schedules of iRT. In consideration of the rarity of abscopal effect, we propose that the occurrence of abscopal effect induced by radiation can be promoted to 100% in view of molecular and genetic level. Furthermore, the “radscopal effect” which refers to using low-dose radiation to reprogram the tumor microenvironment may amplify the occurrence of abscopal effect and overcome the resistance of iRT. Taken together, RT could be regarded as a trigger of systemic antitumor immune response, and with the help of IO can be used as a radical and systemic treatment and be added into current standard regimen of patients with metastatic cancer.

A ‘Hybrid’ Radiotherapy Regimen Designed for Immunomodulation: Combining High-Dose Radiotherapy with Low-Dose Radiotherapy

Simple Summary

Radiotherapy is an important cancer treatment. Aside from its direct killing effect, it also affects anti-tumor immunity. However, radiotherapy’s immune effect is not clear; it depends on the dose and fraction, cancer type, combined immunotherapy, and many other factors. Studies have focused on the optimal radiotherapy regimen to stimulate anti-tumor immunity, but conflicts exist, especially regarding the best radiation dose and fractions. Interestingly, high-dose radiotherapy and low-dose radiotherapy have complementary effects on stimulating anti-tumor immunity. Preclinical studies supporting this finding have accumulated, but gaps between theory and clinical practice still exist. This review summarizes the evidence supporting the use of this ‘hybrid’ radiotherapy approach to effectively stimulate anti-tumor immunity, explains the immune mechanisms of this combination, raises questions that must be addressed in clinical practice, and provides ideas for designing individualized treatment to increase efficiency in stimulating anti-tumor immunity using high-dose plus low-dose radiotherapy.

Abstract

Radiotherapy (RT) affects anti-tumor immunity. However, the exact impact of RT on anti-tumor immune response differs among cancer types, RT dose and fractions, patients’ innate immunity, and many other factors. There are conflicting findings on the optimal radiation dose and fractions to stimulate effective anti-tumor immunity. High-dose radiotherapy (HDRT) acts in the same way as a double-edged sword in stimulating anti-tumor immunity, while low-dose radiotherapy (LDRT) seems to play a vital role in modulating the tumor immune microenvironment. Recent preclinical data suggest that a ‘hybrid’ radiotherapy regimen, which refers to combining HDRT with LDRT, can reap the advantages of both. Clinical data have also indicated a promising potential. However, there are still questions to be addressed in order to put this novel combination therapy into clinical practice. For example, the selection of treatment site, treatment volume, the sequencing of high-dose radiotherapy and low-dose radiotherapy, combined immunotherapy, and so on. This review summarizes the current evidence supporting the use of HDRT + LDRT, explains possible immune biology mechanisms of this ‘hybrid’ radiotherapy, raises questions to be considered when working out individualized treatment plans, and lists possible avenues to increase efficiency in stimulating anti-tumor immunity using high-dose plus low-dose radiotherapy.

Outcome of lung oligometastatic patients treated with stereotactic body irradiation

Purpose

The oligometastatic stage is an intermediate stage of cancer between the localized stage and polymetastatic stage. The prognosis of patients in this stage also appears to be intermediate. Lung stereotactic body radiotherapy is a possible tool for treating oligometastatic lung sites. The objective of our study was to evaluate the clinical outcomes in terms of local control, progression-free survival, overall survival, and toxicity of SBRT in oligometastatic patients with lung metastases from any solid primary tumor.

Materials and methods

Clinical records of consecutive lung oligometastatic patients treated between January 2010 and December 2020 for lung SBRT at 60 Gy in 3- or 8-fraction schedules and a controlled primary tumor were retrospectively analyzed.

Results

After a median follow-up of 20.3 months, local failure occurred for 14 lesions, 57 patients experienced lung progression, and 64 patients experienced disease progression. Overall survival rates at 1 and 2 years were 85.6 and 69.7%, respectively. Fifty-two patients experienced radiation pneumonitis, but only 2 patients were symptomatic and presented grade 2 late pneumonitis. No grade 3-4 toxicity was observed. ECOG 0 was the only prognostic factor for overall survival (HR = 3.5; 95% CI 3.2-3.8; p < 0.01).

Conclusion

SBRT with a 60-Gy schedule in 8 fractions is an effective and well-tolerated treatment for patients with lung oligometastases from any solid primary tumor.

Reshaping the systemic tumor immune environment (STIE) and tumor immune microenvironment (TIME) to enhance immunotherapy efficacy in solid tumors

The development of combination immunotherapy based on the mediation of regulatory mechanisms of the tumor immune microenvironment (TIME) is promising. However, a deep understanding of tumor immunology must involve the systemic tumor immune environment (STIE) which was merely illustrated previously. Here, we aim to review recent advances in single-cell transcriptomics and spatial transcriptomics for the studies of STIE, TIME, and their interactions, which may reveal heterogeneity in immunotherapy responses as well as the dynamic changes essential for the treatment effect. We review the evidence from preclinical and clinical studies related to TIME, STIE, and their significance on overall survival, through different immunomodulatory pathways, such as metabolic and neuro-immunological pathways. We also evaluate the significance of the STIE, TIME, and their interactions as well as changes after local radiotherapy and systemic immunotherapy or combined immunotherapy. We focus our review on the evidence of lung cancer, hepatocellular carcinoma, and nasopharyngeal carcinoma, aiming to reshape STIE and TIME to enhance immunotherapy efficacy.

Multisite Radiotherapy Combined With Tislelizumab for Metastatic Castration-Resistant Prostate Cancer With Second-Line and Above Therapy Failure: Study Protocol for an Open-Label, Single-Arm, Phase Ib/II Study

Background

Tislelizumab combined with radiotherapy as a salvage treatment for patients with end-stage metastatic castration-resistant prostate cancer (mCRPC) is not reported. This study aimed to describe a protocol to evaluate the safety and efficacy of multisite radiotherapy combined with tislelizumab as a salvage therapy for mCRPC in patients who had at least one second-line treatment failure.

Methods

The study included patients with mCRPC who had at least one lesion suitable for radiotherapy and failed androgen deprivation therapy (ADT), followed by at least one novel second-line endocrine therapy. All patients received tislelizumab monotherapy induction therapy for two cycles, then combined with multisite radiotherapy for one cycle, followed by tislelizumab maintenance therapy, until either disease progressed or the patient developed unacceptable toxicity. Radiation methods and lesions were individually selected according to the specified protocol. Primary endpoints included safety and objective response rate. Secondary endpoints included prostate-specific antigen (PSA) response rate, disease control rate, overall survival, radiographic progression-free survival (rPFS), and biochemical progression-free survival (bPFS). Furthermore, the exploratory endpoints included the identification of the predictive biomarkers and exploration of the correlation between biomarkers and the tumor response to the combined regimen.

Discussion

This study included three treatment stages to evaluate the efficacy of immunotherapy and the combination of immunotherapy and radiotherapy for patients with mCRPC who have had at least second-line treatment failure. Additionally, radiation-related and immune-related early and late toxicities were determined, respectively. Furthermore, the study also aimed to identify the predictive biomarkers associated with immunotherapy for treating mCRPC.

Trial Registration

https://www.chictr.org.cn/showproj.aspx?proj=126359, identifier ChiCTR2100046212.

PRaG Therapy of Refractory Metastatic Gastric Cancer: A Case Report

Patients with metastatic gastric cancer had limited treatments and often had a somber prognosis, especially when patients were unable to tolerate high-intensity cytotoxic treatment due to poor physical condition or organ dysfunction after the failure of standard therapy. Here, we reported a metastatic and proficient mismatch repair (pMMR) gastric adenocarcinoma patient with the Eastern Cooperative Oncology Group (ECOG) performance status score of 2 associated with hypoproteinemia and fatigue, and poor appetite that was unable to tolerate high-intensity therapy after several chemotherapy regimens and anti-angiogenic therapy. After receiving novel triple-combination therapy, which consists of PD-1 inhibitor, Radiotherapy and Granulocyte-macrophage colony-stimulating factor (GM-CSF) therapy (PRaG for short), the patient achieved a complete response (CR) with a progression-free survival time of 14 months, and ECOG performance status score improved from 2 to 0. A significant systemic effect was observed in this case and the PRaG triple-combination therapy might provide a novel treatment strategy for metastatic pMMR gastric cancer patients.

Real-world utilization of PD-1/PD-L1 inhibitors with palliative radiotherapy in patients with metastatic non-small cell lung cancer

Background

Programmed cell death protein 1 (PD‐1) blockade plus radiotherapy may be a promising strategy to improve the prognosis of patients with metastatic non‐small cell lung cancer (NSCLC). However, the optimum combined scheme, treatment time of radiotherapy, and irradiated lesion have not been fully determined.

Methods

A total of 321 metastatic NSCLC patients treated with immunotherapy were identified. Among them, 107 patients received PD‐1/PD‐ligand 1 (PD‐L1) inhibitors with radiotherapy, while the remaining cases did not receive radiotherapy. Data on overall survival (OS), progression‐free survival (PFS), treatment response and adverse events were collected. Comparisons based on type of radiation, timing of radiotherapy and number of irradiated lesions were performed.

Results

The median OS in PD‐1/PD‐L1 inhibitors plus radiotherapy was longer than in nonradiotherapy (22.8 vs. 16.6 months, p = 0.022). The median PFS showed a similar trend in this study (9.4 vs. 6.2 months, p = 0.042). Moreover, the combined strategy demonstrated a superior disease control rate and abscopal control rate versus without radiotherapy (both p ≤ 0.001). Further multivariate analysis in the immunotherapy and radiotherapy groups revealed that age below 65 (p = 0.004), Eastern Cooperative Oncology Group performance scores of 0–1 (p = 0.001), oligometastasis (p = 0.006), concurrent combination (p = 0.002), and treated with SRT (p = 0.013) were associated with longer OS. There was a similar incidence of adverse events between the two groups (both p ≥ 0.05).

Conclusions

The combination of PD‐1/PD‐L1 inhibitors plus palliative radiotherapy demonstrated favorable survival and good tolerability in metastatic NSCLC patients.