Chemopreventive agents induce programmed death-1-ligand 1 (PD-L1) surface expression in breast cancer cells and promote PD-L1-mediated T cell apoptosis

Use of Total Neoadjuvant Therapy for Locally Advanced Rectal Cancer: Initial Results From the Pembrolizumab Arm of a Phase 2 Randomized Clinical Trial

IMPORTANCE

Total neoadjuvant therapy (TNT) is often used to downstage locally advanced rectal cancer (LARC) and decrease locoregional relapse; however, more than one-third of patients develop recurrent metastatic disease. As such, novel combinations are needed.

OBJECTIVE

To assess whether the addition of pembrolizumab during and after neoadjuvant chemoradiotherapy can lead to an improvement in the neoadjuvant rectal (NAR) score compared with treatment with FOLFOX (5-fluorouracil, leucovorin, and oxaliplatin) and chemoradiotherapy alone.

DESIGN, SETTING, AND PARTICIPANTS

In this open-label, phase 2, randomized clinical trial (NRG-GI002), patients in academic and private practice settings were enrolled. Patients with stage II/III LARC with distal location (cT3-4 ≤ 5 cm from anal verge, any N), with bulky disease (any cT4 or tumor within 3 mm of mesorectal fascia), at high risk for metastatic disease (cN2), and/or who were not candidates for sphincter-sparing surgery (SSS) were stratified based on clinical tumor and nodal stages. Trial accrual opened on August 1, 2018, and ended on May 31, 2019. This intent-to-treat analysis is based on data as of August 2020.

INTERVENTIONS

Patients were randomized (1:1) to neoadjuvant FOLFOX for 4 months and then underwent chemoradiotherapy (capecitabine with 50.4 Gy) with or without intravenous pembrolizumab administered at a dosage of 200 mg every 3 weeks for up to 6 doses before surgery.

MAIN OUTCOMES AND MEASURES

The primary end point was the NAR score. Secondary end points included pathologic complete response (pCR) rate, SSS, disease-free survival, and overall survival. This report focuses on end points available after definitive surgery (NAR score, pCR, SSS, clinical complete response rate, margin involvement, and safety).

RESULTS

A total of 185 patients (126 [68.1%] male; mean [SD] age, 55.7 [11.1] years) were randomized to the control arm (CA) (n = 95) or the pembrolizumab arm (PA) (n = 90). Of these patients, 137 were evaluable for NAR score (68 CA patients and 69 PA patients). The mean (SD) NAR score was 11.53 (12.43) for the PA patients (95% CI, 8.54-14.51) vs 14.08 (13.82) for the CA patients (95% CI, 10.74-17.43) (P = .26). The pCR rate was 31.9% in the PA vs 29.4% in the CA (P = .75). The clinical complete response rate was 13.9% in the PA vs 13.6% in the CA (P = .95). The percentage of patients who underwent SSS was 59.4% in the PA vs 71.0% in the CA (P = .15). Grade 3 to 4 adverse events were slightly increased in the PA (48.2%) vs the CA (37.3%) during chemoradiotherapy. Two deaths occurred during FOLFOX: sepsis (CA) and pneumonia (PA). No differences in radiotherapy fractions, FOLFOX, or capecitabine doses were found.

CONCLUSIONS AND RELEVANCE

Pembrolizumab added to chemoradiotherapy as part of total neoadjuvant therapy was suggested to be safe; however, the NAR score difference does not support further study.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02921256.

PD-1 Involvement in Peripheral Blood CD8+ T Lymphocyte Dysfunction in Patients with Acute-on-chronic Liver Failure

BACKGROUND AND AIMS

Programmed cell death-1 (PD-1) plays an important role in downregulating T lymphocytes but the mechanisms are still poorly understood. This study aimed to explore the role of PD-1 in CD8⁺ T lymphocyte dysfunction in hepatitis B virus (HBV)-related acute-on-chronic liver failure (ACLF).

METHODS

Thirty patients with HBV-ACLF and 30 healthy controls (HCs) were recruited. The differences in the numbers and functions of CD8⁺ T lymphocytes, PD-1 and glucose transporter-1 (Glut1) expression from the peripheral blood of patients with HBV-ACLF and HCs were analyzed. In vitro, the CD8⁺ T lymphocytes from HCs were cultured (HC group) and the CD8⁺ T lymphocytes from ACLF patients were cultured with PD-L1-IgG (ACLF+PD-1 group) or IgG (ACLF group). The numbers and functions of CD8⁺ T lymphocytes, PD-1 expression, glycogen uptake capacity, and Glut1, hexokinase-2 (HK2), and pyruvate kinase (PKM2) expression were analyzed among the HC group, ACLF group and ACLF+ PD-1group.

RESULTS

The absolute numbers of CD8⁺ T lymphocytes in the peripheral blood from patients with HBV-ACLF were lower than in the HCs (p<0.001). The expression of PD-1 in peripheral blood CD8⁺ T lymphocytes was lower in HCs than in patients with HBV-ACLF (p=0.021). Compared with HCs, PD-1 expression was increased (p=0.021) and Glut1 expression was decreased (p=0.016) in CD8⁺ T lymphocytes from the HBV-ACLF group. In vitro, glycogen uptake and functions of ACLF CD8⁺ T lymphocytes were significantly lower than that in HCs (p=0.017; all p<0.001). When PD-1/PD-L1 was activated, the glycogen uptake rate and expression levels of Glut1, HK2, and PKM2 showed a decreasing trend (ACLF+PD-1 group compared to ACLF group , all p<0.05). The functions of CD8⁺ T lymphocytes in the ACLF+PD-1 group [using biomarkers of Ki67, CD69, IL-2, interferon-gamma, and tumor necrosis factor-alpha- were lower than in the ACLF group (all p<0.05).

CONCLUSIONS

CD8⁺ T lymphocyte dysfunction is observed in patients with HBV-ACLF. PD-1-induced T lymphocyte dysfunction might involve glycolysis inhibition.

Efficacy and safety of anti-PD-1 inhibitor combined with nab-paclitaxel in Chinese patients with refractory melanoma

PURPOSE

This retrospective study aimed to evaluate the combined effect of anti-PD-1 inhibitor and nanoparticle albumin-bound (nab)-paclitaxel for refractory melanoma among Chinese patients.

METHODS

Data from January 2018 to March 2021 were retrospectively collected and analyzed. Sixty-four patients were eligible for analysis from a single Chinese cancer center.

RESULTS

The median follow-up was 16.0 months at data cutoff. The objective response rate (ORR) was 29.7%, and the disease control rate (DCR) was 67.2% in all patients. Treatment-naïve patients had significantly higher ORR than pretreated patients (42.9% vs 13.8%, p = 0.011). Cutaneous melanoma patients with NRAS gene mutation benefited more than non-mutated patients (DCR of 100% vs. 54.5%) (p = 0.030). The median progression-free survival (mPFS) of all patients was 5.2 months and the duration of response was 10.8 months. Median duration of disease control was 7.7 months. Prior treatment-naïve patients had significantly longer PFS than those who accepted prior treatments (7.2 vs. 5.1 months, p = 0.024). Patients with abnormally high LDH level had shorter mPFS (3.6 months vs. 6.6 months, p = 0.020). Median overall survival was not reached in this study. Most patients experienced adverse events (AEs), but only 17.2% of patients experienced grade 3 severe AEs. The most common AEs were alopecia (89.1%), neutropenia (18.8%), pruritus (15.6%), and arthralgia (14.1%). Some patients had immune related AEs (irAEs). No grade 4 or 5 AEs were observed. Patients with ≥ 3 AEs or with irAEs had longer mPFS (p < 0.05).

CONCLUSION

Nab-paclitaxel combined with PD-1 antibody is a well-tolerated and effective regimen for Chinese patients with refractory melanoma.

Effects of a Novel Thiadiazole Derivative with High Anticancer Activity on Cancer Cell Immunogenic Markers: Mismatch Repair System, PD-L1 Expression, and Tumor Mutation Burden

Microsatellite instability (MSI), tumor mutation burden (TMB), and programmed cell death ligand-1 (PD-L1) are particularly known as immunotherapy predictive biomarkers. MSI and TMB are closely related to DNA mismatch repair (MMR) pathway functionality, while the PD-L1 checkpoint mediates cancer cell evasion from immune surveillance via the PD-L1/PD-1 axis. Among all the novel triazolo[3,4-b]thiadiazole derivatives, the compound KA39 emerged as the most potent anticancer agent. In the present study, potential alterations in MSI, TMB, and/or PD-L1 expression upon cell treatment with KA39 are explored. We tested three MMR-deficient (DLD-1, LS174T, and DU-145) and two MMR-proficient (HT-29 and PC-3) human cancer cell lines. Our findings support KA39-induced PD-L1 overexpression in all cancer cell lines, although the most outstanding increase was observed in MMR-proficient HT-29 cells. MSI analysis showed that KA39 affects the MMR system, impairing its recognition or repair activity, particularly in MMR-deficient DLD-1 and DU-145 cells, enhancing oligonucleotide production. There were no remarkable alterations in the TMB between untreated and treated cells, indicating that KA39 does not belong to mutagenic agents. Taking together the significant in vitro anticancer activity with PD-L1 upregulation and MSI increase, KA39 should be investigated further for its implication in chemo-immunotherapy of cancer.

Curative-Intent Treatment with Durvalumab in Early-Stage Cancers

The introduction of immunotherapy has fundamentally transformed the treatment landscape in cancer, providing long-term survival benefit for patients with advanced disease across multiple tumor types, including non-small cell lung cancer (NSCLC). In the placebo-controlled phase 3 PACIFIC trial, the PD-L1 inhibitor durvalumab demonstrated significant improvements in progression-free survival and overall survival in patients with unresectable, stage III NSCLC who had not progressed after platinum-based chemoradiotherapy (CRT). These findings have led to the widespread acceptance of the 'PACIFIC regimen' (durvalumab after CRT) as the standard of care in this setting. Moreover, the PACIFIC trial is the first study to demonstrate a proven survival advantage with an immunotherapy in a curative-intent setting, thereby providing a strong rationale for further investigation of durvalumab in early-stage cancers. Herein, we describe the extensive clinical development program for durvalumab across multiple tumor types in curative-intent settings, outlining the scientific rationale(s) for its use and highlighting the innovative research (e.g., personalized cancer monitoring) advanced by these trials.

Immune System-Related Changes in Preclinical GL261 Glioblastoma under TMZ Treatment: Explaining MRSI-Based Nosological Imaging Findings with RT-PCR Analyses

Glioblastomas (GB) are brain tumours with poor prognosis even after aggressive therapy. Previous work suggests that magnetic resonance spectroscopic imaging (MRSI) could act as a biomarker of efficient immune system attack onto GB, presenting oscillatory changes. Glioma-associated microglia/macrophages (GAMs) constitute the most abundant non-tumour cell type within the GB and can be polarised into anti-tumour (M1) or pro-tumour (M2) phenotypes. One of the mechanisms to mediate immunosuppression in brain tumours is the interaction between programmed cell death-1 ligand 1 (PD-L1) and programmed cell death-1 receptor (PD-1). We evaluated the subpopulations of GAMs in responding and control GB tumours to correlate PD-L1 expression to GAM polarisation in order to explain/validate MRSI-detected findings. Mice were evaluated by MRI/MRSI to assess the extent of response to treatment and with qPCR for GAMs M1 and M2 polarisation analyses. M1/M2 ratios and PD-L1 expression were higher in treated compared to control tumours. Furthermore, PD-L1 expression was positively correlated with the M1/M2 ratio. The oscillatory change in the GAMs prevailing population could be one of the key causes for the differential MRSI-detected pattern, allowing this to act as immune system activity biomarker in future work.

Immune Monitoring in Melanoma and Urothelial Cancer Patients Treated with Anti-PD-1 Immunotherapy and SBRT Discloses Tumor Specific Immune Signatures

Simple Summary

Currently available biomarkers for response to checkpoint inhibitors are incomplete and predominantly focus on tumor tissue analysis e.g., tumor mutational burden, programmed cell death-ligand 1 (PD-L1) expression. Biomarkers in peripheral blood would allow a more dynamic monitoring and could offer a way for sequential adaptation of treatment strategy. We conducted an in-depth analysis of baseline and on-treatment systemic immune features in a cohort of stage III/IV melanoma and stage IV urothelial cancer (UC) patients treated with anti-programmed cell death-1 (anti-PD-1) therapy combined with stereotactic body radiotherapy (SBRT) in a similar regimen/schedule. Baseline immunity was clearly different between these two cohorts, indicating a less active immune landscape in UC patients. This study also detected signatures of proliferation in the CD8⁺ T-cell compartment pre-treatment and early after anti-PD-1 initiation that were positively correlated with clinical outcome in both tumor types. In addition our data support the biological relevance of PD-1/PD-L1 expression on circulating immune cell subsets, especially in melanoma.

Abstract

(1) Background: Blockade of the PD-1/PD-L1 pathway has revolutionized the oncology field in the last decade. However, the proportion of patients experiencing a durable response is still limited. In the current study, we performed an extensive immune monitoring in patients with stage III/IV melanoma and stage IV UC who received anti-PD-1 immunotherapy with SBRT. (2) Methods: In total 145 blood samples from 38 patients, collected at fixed time points before and during treatment, were phenotyped via high-parameter flow cytometry, luminex assay and UPLC-MS/MS. (3) Results: Baseline systemic immunity in melanoma and UC patients was different with a more prominent myeloid compartment and a higher neutrophil to lymphocyte ratio in UC. Proliferation (Ki67⁺) of CD8⁺ T-cells and of the PD-1⁺/PD-L1⁺ CD8⁺ subset at baseline correlated with progression free survival in melanoma. In contrast a higher frequency of PD-1/PD-L1 expressing non-proliferating (Ki67⁻) CD8⁺ and CD4⁺ T-cells before treatment was associated with worse outcome in melanoma. In UC, the expansion of Ki67⁺ CD8⁺ T-cells and of the PD-L1⁺ subset relative to tumor burden correlated with clinical outcome. (4) Conclusion: This study reveals a clearly different immune landscape in melanoma and UC at baseline, which may impact immunotherapy response. Signatures of proliferation in the CD8⁺ T-cell compartment prior to and early after anti-PD-1 initiation were positively correlated with clinical outcome in both cohorts. PD-1/PD-L1 expression on circulating immune cell subsets seems of clinical relevance in the melanoma cohort.

Vincristine upregulates PD-L1 and increases the efficacy of PD-L1 blockade therapy in diffuse large B-cell lymphoma

BACKGROUND

Some chemotherapy drugs have immunomodulatory effects on specific tumors. The potential of vincristine (VCR) in the R-CHOP regimen to act as both a chemotherapeutic and an immunomodulatory agent via PD-L1 in tumor cells remains unclear.

METHODS

In vitro screening VCR showed that the IC50 value of VCR in the DLBCL cell lines was approximately 2 nM. Western blotting and q-PCR were used to detect the expression of PD-L1. The effect of VCR combined with PD-L1 mAb was tested in a co-culture system of LY-OCI-3 cells and peripheral blood mononuclear cells and in DLBCL xenograft mouse model. Flow cytometry was used to determine the proportion of T lymphocyte subsets. The effect of the STAT3 inhibitor nifuroxazide on VCR-induced PD-L1 expression was tested in LY-OCI-3 and SU-DHL-4 cells.

RESULTS

VCR upregulated PD-L1 protein and mRNA expression in various DLBCL cell lines. PD-L1 Ab combined with VCR significantly increased the proportion of CD8 + Granzyme B + , INF-γ + or TNF-α + CD3 + T cells. VCR + PD-L1 Ab inhibited tumor growth more effectively than VCR monotherapy, whereas PD-L1 Ab alone had no significant effect. Survival time did not differ significantly between the PD-L1 Ab group and the control group, whereas it was significantly longer in the VCR monotherapy and combination groups which showed more longer survival compared with the former. Nifuroxazide downregulated p-STAT3 and PD-L1 protein levels.

CONCLUSIONS

VCR upregulated PD-L1 expression in DLBCL cells partially by promoting the p-STAT3; VCR combined with PD-L1 Ab activated effector T cells and increased the antitumor immune response in vitro and in vivo.

Programmed cell death 1 as prognostic marker and therapeutic target in upper gastrointestinal cancers

Gastrointestinal (GIs) cancers are among the most common causes of cancer related death, and hence the importance for the identification of novel prognostic/predictive biomarkers for detection of patients at an early stage, and for using these to identify novel targeted therapies to improve the efficacy of existing chemotherapeutic regimens. Programmed cell death 1 has been reported as a potential target in several malignancies, and targeting agents are being developed, some already approved by FDA, such as: pembrolizumab, Atezolizumab, Nivolumab. Pembrolizumab that have been approved for the treatment of metastatic non-small cell lung cancer. Here we provide an overview of the mechanism of action PD-1/PD-L1, prognostic value and current progress in clinical trials using PD-1/PD-L1 inhibitors, and the resistant mechanisms at underlie the inhibitory effect of these agents in the treatment of gastrointestinal cancers.

Cancer-on-a-Chip for Modeling Immune Checkpoint Inhibitor and Tumor Interactions

Cancer immunotherapies, including immune checkpoint inhibitor (ICI)-based therapies, have revolutionized cancer treatment. However, patient response to ICIs is highly variable, necessitating the development of methods to quickly assess efficacy. In this study, an array of miniaturized bioreactors has been developed to model tumor-immune interactions. This immunotherapeutic high-throughput observation chamber (iHOC) is designed to test the effect of anti-PD-1 antibodies on cancer spheroid (MDA-MB-231, PD-L1+) and T cell (Jurkat) interactions. This system facilitates facile monitoring of T cell inhibition and reactivation using metrics such as tumor infiltration and interleukin-2 (IL-2) secretion. Status of the tumor-immune interactions can be easily captured within the iHOC by measuring IL-2 concentration using a micropillar array where sensitive, quantitative detection is allowed after antibody coating on the surface of array. The iHOC is a platform that can be used to model and monitor cancer-immune interactions in response to immunotherapy in a high-throughput manner.

Triplet combination of durvalumab, tremelimumab, and paclitaxel in biliary tract carcinomas: Safety run-in results of the randomized IMMUNOBIL PRODIGE 57 phase II trial

BACKGROUND

The IMMUNOBIL PRODIGE 57 trial is a non-comparative randomized phase II study assessing the efficacy and safety of the durvalumab (an anti-PD-L1) and tremelimumab (an anti-CTLA4) combination with or without weekly paclitaxel in patients with advanced biliary tract carcinoma (BTC) after failure of platinum-based chemotherapy. Taxanes have already been safely combined with immune checkpoint inhibitors in other tumors. We report results of the 20-patient safety run-in.

METHODS

Patients received durvalumab (1500 mg at day 1 [D1] of each cycle)/tremelimumab (75 mg at D1 for 4 cycles; Arm A) or durvalumab/tremelimumab with paclitaxel (80 mg/m2 at D1, D8, D15; Arm B) every 28 days.

RESULTS

Twenty patients were enrolled (Arm A/B: 10/10). There were no dose-limiting toxicities (DLTs) in Arm A. Six DLTs were observed in five patients (50%) in Arm B, meeting a stopping rule for the trial inclusions. DLTs included three serious anaphylactic reactions (with one cardiac arrest), two enterocolitis, and one infectious pneumopathy with septic shock. There were no patients with history of personal or familial auto-immune disease.

CONCLUSION

The safety run-in part of IMMUNOBIL PRODIGE 57 raised concerns regarding co-administration of paclitaxel with durvalumab and tremelimumab in BTC, with an unexpected increase in anaphylactic adverse events. Phase II of the study will only evaluate the durvalumab and tremelimumab combination arm.

CLINICALTRIALS REGISTRATION

NCT03704480.

Beyond chemoradiotherapy: improving treatment outcomes for patients with stage III unresectable non-small-cell lung cancer through immuno-oncology and durvalumab (Imfinzi®▼, AstraZeneca UK Limited)

The treatment paradigm of non-small-cell lung cancer (NSCLC) has rapidly changed in recent years following the introduction of immune-checkpoint inhibition (ICI). Pre-clinically, both chemotherapy and radiotherapy modulate the tumour microenvironment, providing the rationale for clinical trials evaluating their role in combination with immunotherapy. Standard-of-care treatment for patients with unresectable stage III disease is concurrent chemoradiotherapy (cCRT); however, only recently, the combination with ICI has been explored. The Phase 3 PACIFIC study randomised 713 patients with confirmed locally advanced, unresectable, stage III NSCLC, whose disease has not progressed following cCRT, to either the anti-programmed death-ligand 1 (PD-L1) agent durvalumab (Imfinzi®▼, AstraZeneca UK Limited) or placebo. Patients with a PD-L1 status ≥1% treated with durvalumab had a significantly longer median progression-free survival compared with placebo (17.2 vs. 5.6 months, respectively; HR: 0.51; 95% CI: 0.41-0.63), prolonged median overall survival (OS) (NR vs. 28.7 months, respectively; HR: 0.68; 99.73% CI: 0.47-0.997; P = 0.0025) and long-term clinical benefit (3-year OS HR: 0.69; 95% CI: 0.55-0.86). Grade 3 or 4 toxicity was marginally greater in the durvalumab cohort versus placebo (30.5% vs. 26.1%). Based on these results, durvalumab has been licensed in this setting, and further clinical trials are exploring the use of ICI in unresectable stage III NSCLC.

Anti-PD-1 Immunotherapy in Preclinical GL261 Glioblastoma: Influence of Therapeutic Parameters and Non-Invasive Response Biomarker Assessment with MRSI-Based Approaches

Glioblastomas (GBs) are malignant brain tumours with poor prognosis even after aggressive therapy. Programmed cell death-1 (PD-1) immune checkpoint blockade is a promising strategy in many types of cancer, but its therapeutic effects in GB remain low and associated with immune infiltration. Previous work suggests that oscillations of magnetic resonance spectroscopic imaging (MRSI)-based response pattern with chemotherapy could act as a biomarker of efficient immune system attack onto GBs. The presence of such oscillations with other monotherapies such as anti-PD-1 would reinforce its monitoring potential. Here, we confirm that the oscillatory behaviour of the response biomarker is also detected in mice treated with anti PD-1 immunotherapy both in combination with temozolomide and as monotherapy. This indicates that the spectral pattern changes observed during therapy response are shared by different therapeutic strategies, provided the host immune system is elicited and able to productively attack tumour cells. Moreover, the participation of the immune system in response is also supported by the rate of cured animals observed with different therapeutic strategies (in the range of 50–100% depending on the treatment), which also held long-term immune memory against tumour cells re-challenge. Taken together, our findings open the way for a translational use of the MRSI-based biomarker in patient-tailored GB therapy, including immunotherapy, for which reliable non-invasive biomarkers are still missing.

An increase of CD8+ T cell infiltration following recurrence is a good prognosticator in HNSCC

Programmed death-ligand 1 (PD-L1) expression and CD8-positive tumor-infiltrating lymphocyte (CD8⁺ TIL) infiltration are essential biomarkers for immune checkpoint inhibitor therapy. The objective of this study was to compare the expression of those biomarkers between initial and recurrent HNSCCs using paired analysis. Prognostic significance of those immunological changes was also investigated. Forty-two consecutive patients with locally recurrent HNSCCs were included. Immunohistochemical staining of CD8 and PD-L1 was done for both initial and recurrent tumor specimens. The IHC findings were verified with mRNA expression profiling. Also, the prognostic impact was analyzed based on overall survival (OS). Recurrent-to-initial (R/I) ratios of CD8⁺ TILs and PD-L1 were widely variable. CD8⁺ TIL density and PD-L1 expression decreased in 59.5% and 69% of patients, respectively (R/I ratio < 1). The R/I ratio of CD8A mRNA was significantly higher in patients with a CD8 R/I ratio > 1 (1.7 ± 1.5 vs. 0.6 ± 0.6, p = 0.042). CD8 R/I ratio (> 1) was a good prognosticator for OS (HR 0.293, 95% CI 0.091-0.945, p = 0.040). CD8⁺ TIL infiltration and PD-L1 expression changed variably following local recurrence of HNSCC. The increase of CD8⁺ TILs at recurrence was an excellent independent prognosticator.

Pulmonary Complications of Immunotherapy

Immune checkpoint inhibitor (ICI) therapy represents a paradigm shift in the treatment of patients with locally advanced and metastatic lung cancer. Although immunotherapy generally has a more favorable safety profile when compared with chemotherapy, immune-related adverse events represent important, but incompletely understood, treatment-limiting complications associated with significant morbidity and mortality risk. Current guidelines for diagnosis and management are derived from consensus experience, highlighting that further prospective investigation in this area is needed. As ICI-related pneumonitis is a clinically and radiographically diverse toxidrome, clinical vigilance is important while treating patients with lung cancer.

A narrative review of synergistic drug administration in unresectable locally advanced non-small cell lung cancer: current landscape and future prospects in the era of immunotherapy

Based on the PACIFIC study, the standard care of unresectable locally advanced non-small cell lung cancer (LA-NSCLC) shifted from concurrent chemo-radiotherapy (CCRT) alone to CCRT followed by durvalumab consolidation in 2017. In the era of immunotherapy, two kinds of therapeutic drugs are involved in the management of LA-NSCLC: chemotherapeutics and anti-PD-1/PD-L1 agents. However, the best choices of systematic chemotherapy, immunotherapy, and treatment schedule remain controversial. The immune modulation effects of chemotherapy, as well as the potential immunosuppressive impact of pretreatment medications, should be taken into consideration. Indeed, chemotherapeutics are double-edged swords to immunotherapy, with both stimulatory and suppressive effects on the immune system. Moreover, low-dose chemotherapy is reported to enhance anti-tumor immune responses with reduced toxicities. As for glucocorticoids, there is no consensus about its exact impact on the efficacy of immunotherapy. In addition, the timing of anti-PD-1/PD-L1 agent related to CCRT has three modes: induction, concurrent, and consolidation therapy. Although CCRT followed by durvalumab consolidation is the standard of care, the best sequence of immunotherapy and chemo-radiotherapy is still under debate. Furthermore, the efficacy and toxicity of various PD-1/PD-L1 inhibitors should be compared, especially in the background of CCRT. In this review, we will summarize the detailed knowledge about chemotherapeutics and anti-PD-1/PD-L1 axis agents, and discuss the potential implications in designing novel, effective treatment strategies for LA-NSCLC.

Resisting Resistance to Immune Checkpoint Therapy: A Systematic Review

The treatment landscape in oncology has witnessed a major revolution with the introduction of checkpoint inhibitors: anti-PD1, anti-PDL1 and anti-CTLA-4. These agents enhance the immune response towards cancer cells instead of targeting the tumor itself, contrary to standard chemotherapy. Although long-lasting durable responses have been observed with immune checkpoints inhibitors, the response rate remains relatively low in many cases. Some patients respond in the beginning but then eventually develop acquired resistance to treatment and progress. Other patients having primary resistance never respond. Multiple studies have been conducted to further elucidate these variations in response in different tumor types and different individuals. This paper provides an overview of the mechanisms of resistance to immune checkpoint inhibitors and highlights the possible therapeutic approaches under investigation aiming to overcome such resistance in order to improve the clinical outcomes of cancer patients.

PD-1/PD-L1 axis importance and tumor microenvironment immune cells

Triple-negative breast cancer (TNBC) is heterogeneous cancer with poor prognosis among the other breast tumors. Rapid recurrence and increased progression rate could be reasons for the poor prognosis of this type of breast cancer. Recently, because of the lack of specific targets in multiple cancer treatment, immune checkpoint blockade therapies with targeting PD-1/PD-L1 axis have displayed significant advances and improved survival. Among different types of breast cancers, TNBC is considered more immunogenic with high T-cell and other immune cells infiltration compared to other breast cancer subtypes. This immunogenic characteristic of TNBC is a beneficial marker in the immunotherapy of these tumors. Clinical studies with a focus on immune checkpoint therapy have demonstrated promising results in TNBC treatment. In this review, we summarize clinical trials with the immunotherapy-based treatment of different cancers and also discuss the interaction between infiltrating immune cells and breast tumor microenvironment. In addition, we focus on the signaling pathway that controls PD-L1 expression and continues with CAR T-cell therapy and siRNA as novel strategies and potential tools in targeted therapy.

The changing landscape of stage III lung cancer: a literature review

INTRODUCTION

The treatment of stage III non-small cell lung cancer (NSCLC) remains challenging and associated with overall poor outcomes. Since seminal studies in the early 90s introduced concurrent chemo-radiotherapy as standard of care for treatment of this disease, no major advances have been introduced in this landscape. Both radiation dose escalation and neoadjuvant/adjuvant chemotherapy strategies were unsuccessful to improve the survival over standard of care radiation dose and chemotherapy schedule: five-year overall survival (OS) ranging from 15-20%. However, in 2017 the PACIFIC Trial demonstrated that the addition of consolidative immune checkpoint inhibitor durvalumab for 1 year led to superior progression-free survival (PFS) and 3-year overall survival with no significant increase in toxicity compared to placebo in patients who achieved disease control with concurrent chemo-RT.

AREAS COVERED

This article reviews the treatment evolution of stage III NSCLC over the past decades, discusses current standard of care strategies, and highlights potential future directions for the management of this condition.

EXPERT OPINION

Ongoing trials incorporating upfront checkpoint inhibitors with radiotherapy will answer whether adding checkpoint inhibitors to chemotherapy or substituting them for chemotherapy altogether will improve long-term outcome.

Immunostimulatory and anti-tumor metronomic cyclophosphamide regimens assessed in primary orthotopic and metastatic murine breast cancer

The impressive successes of immune checkpoint blockade antibodies to treat various types of cancer are limited to minor subsets of patients. Combination therapy strategies, including with chemotherapy, are being explored to possibly improve the efficacy of immunotherapies. Here we report results regarding the use of an immunostimulatory regimen of metronomic cyclophosphamide (CTX). We show that in orthotopic models of syngeneic murine triple-negative breast cancer (EMT6), CTX administered at 140 mg/kg every 6 days (CTX140 1q6d) is superior at inhibiting primary tumor growth when compared to maximum tolerated dose or daily oral (continuous) low-dose CTX. In SCID or SCID beige mice, anti-tumor effects of CTX140 1q6d are reduced, reinforcing the therapeutic contribution of the adaptive and innate immune systems. In a second breast cancer model (SP1-AC2M2), CTX140 1q6d again showed clear superiority in anti-tumor effects, causing complete tumor regressions; however, these mice were not protected from subsequent tumor re-challenge, suggesting absence of immune memory. We also show that in an aggressive and metastatic cisplatin-resistant variant (EMT6-CDDP), CTX140 1q6d is superior and invokes an influx of intra-tumoral CD4+ and CD8+ T cells. CTX increases expression of tumor cell PD-L1; however, when combined with concomitant PD-L1 antibody therapy none of the CTX regimens showed increased benefit. This work sheds light on the potential use of metronomic CTX for the treatment of breast cancer, in particular using the quasi-weekly regimen, but also underscores the complexity of the anti-tumor mechanisms and potential to improve immune checkpoint therapy efficacy.

The deubiquitinase USP22 regulates PD-L1 degradation in human cancer cells

Background

Many cancers evade immune surveillance by overexpressing PD-L1. PD-L1 interacted with its receptor PD-1, resulting in reduction of T cell proliferation and activation and thereafter cancer cell death mediated by T-lymphocyte. Understanding the mechanisms that regulate PD-L1 was of vital importance for immune checkpoint blockade therapy (ICBT).

Methods

Human non-small cell lung cancer cells and 293FT cells were used to investigate the function of USP22 upon PD-L1 and CSN5 by WB, Immunoprecipitation, Immunofluorescence and Flow cytometry analysis. B16-F10 cells were used to explore the role of USP22 on tumorigenesis and T cell cytotoxicity. The relationship between USP22 and PD-L1 expression was investigated by Immunohistochemistry analysis in human non-small cell lung cancer samples.

Results

Our data showed that USP22 interacted with PD-L1 and promoted its stability. USP22 deubiquitinated PD-L1 and inhibited its proteasome degradation. Moreover, USP22 also interacted with CSN5 and stabilized CSN5 through deubiquitination. Either USP22 or CSN5 could facilitate the interaction of PD-L1 with the other one. Furthermore, USP22 removed K6, K11, K27, K29, K33 and K63-linked ubiquitin chain of both CSN5 and PD-L1. In addition, USP22 depletion inhibited tumorigenesis and promoted T cell cytotoxicity. Besides, USP22 expression positively correlated with PD-L1 expression in human non-small cell lung cancer samples.

Conclusions

Here, we suggested that USP22 is a new regulator for PD-L1. On the one hand, USP22 could directly regulate PD-L1 stability through deubiquitination. On the other hand, USP22 regulated PD-L1 protein level through USP22-CSN5-PD-L1 axis. In addition, USP22 depletion inhibited tumorigenesis and promoted T cell cytotoxicity. Besides, USP22 expression positively correlated with PD-L1 expression in human non-small cell lung cancer samples. Together, we identified a new regulator of PD-L1 and characterized the important role of USP22 in PD-L1 mediated immune evasion. Targeting USP22 might be a new solution to ICBT.

Checkpoint Blockade in Combination With Doxorubicin Augments Tumor Cell Apoptosis in Osteosarcoma

The aim of this study was to provide a basis for the theory that the combination of conventional chemotherapy and immunotherapy would be an effective treatment for osteosarcoma. Here, the expression of programmed death ligand 1 (PD-L1) in 26 clinical osteosarcoma tissue samples collected before and after chemotherapy was analyzed. The effects of osteosarcoma cells treated with doxorubicin, a conventional chemotherapeutic agent, on the proliferation and apoptosis of CD8 T lymphocytes were investigated in vitro. Thereafter, the effectiveness of doxorubicin combined with an anti-PD-L1 antibody as an osteosarcoma therapy was tested in 24 subcutaneous tumor mouse models. The results showed that the expression of PD-L1 was upregulated by chemotherapy in both the clinical osteosarcoma tissue samples and the osteosarcoma cell lines. The proliferation of CD8 T lymphocytes was inhibited, and apoptosis in CD8 T lymphocytes was enhanced by the doxorubicin-pretreated osteosarcoma cells, whereas this effect was reversed by the anti-PD-L1 antibody. A more effective result was observed when doxorubicin was combined with the anti-PD-L1 antibody in vivo. In short, the combination of conventional chemotherapy and an anti-PD-L1 antibody might be an effective option for osteosarcoma treatment, as anti-PD-L1 antibody can reverse the immunosuppression induced by chemotherapy.

Variation of Programmed Death Ligand 1 Expression After Platinum-based Neoadjuvant Chemotherapy in Lung Cancer

The effect of chemotherapy on programmed cell death-ligand 1 (PD-L1) expression has been previously studied in lung cancer, while the results remain controversial. The aim of this study was to investigate the variation of PD-L1 expression after neoadjuvant chemotherapy and explore the association between chemotherapy response, prognosis and the variation of PD-L1 expression in lung cancer patients. A total of 63 lung cancer patients who received platinum-based neoadjuvant chemotherapy and subsequently underwent surgical resection were selected. PD-L1 expression on tumor cells (TC) and tumor-infiltrating immune cells (IC) was assessed by immunohistochemistry using 22C3 monoclonal antibody in these 63 matched lung cancer specimens before and after neoadjuvant chemotherapy. The positivity of PD-L1 on TC changed from 17.5% to 39.7% after neoadjuvant chemotherapy and the positivity of PD-L1 on IC changed from 19.0% to 71.4% after neoadjuvant chemotherapy. The elevation of PD-L1 expression on TC after neoadjuvant chemotherapy was more frequently observed in patients achieving stable disease or progressive disease than in patients achieving partial response (P=0.026). Patients with elevated PD-L1 expression on TC after neoadjuvant chemotherapy showed a trend to have a shorter progression-free survival than patients without elevated PD-L1 expression on TC, although the difference was not statistically significant in multivariate analysis (hazard ratio=2.38, 95% confidence interval=0.99-5.73, P=0.053). PD-L1 expression can be elevated by chemotherapy in lung cancer. Furthermore, elevation of PD-L1 expression on TC after neoadjuvant chemotherapy was associated with reduced chemotherapy response and inferior progression-free survival in patients with lung cancer.

Variation of PD-L1 expression in locally advanced cervical cancer following neoadjuvant chemotherapy

Background

High Programmed death ligand 1 (PD-L1) expression are thought to be necessary to PD-1/PD-L1 axis blockades in many tumors. The aim of the study was to explore the variation of PD-L1 expression after neoadjuvant chemotherapy (NAC) in cervical squamous cell carcinoma (SCC) and its clinical implications.

Methods

A total of 142 paired SCC specimens before and after platinum-based NAC were obtained from cervical cancer patients. The expression of PD-L1 and CD3+, CD4+, CD8+ tumor infiltrating lymphocytes (TILs) was detected by immunohistochemistry and the association between TILs, chemotherapy response, clinical outcome and PD-L1 expression was evaluated.

Results

The fraction of patients with high PD-L1 expression was significantly increased from 32.4 to 46.5% after NAC (χ2 = 5.897, p = 0.015), while the increase of CD3+, CD4+, CD8+ TILs was not significant. High PD-L1 expression was not associated with CD3+, CD4+, CD8+ TILs before NAC, however CD8+ TILs infiltration was positively associated with high PD-L1 expression after NAC (r = 0.205, p = 0.014). The decreased PD-L1 expression was more observed in patients with clinical response to NAC (χ2 = 6.890, p = 0.009). A longer DFS was seen in patients with decreased PD-L1 expression than those with elevated or stable PD-L1 expression (p = 0.048, 95% CI: 0.091–0.987), while the difference was not significant in multivariate analysis (p = 0.113, 95% CI: 0.108–1.266).

Conclusions

Cisplatin based chemotherapy can increase PD-L1 expression in cervical cancer. The increased PD-L1 expression and a lymphocyte predominant microenvironment after chemotherapy provide a rational for use of PD-1/PD-L1 axis-inhibitor in the neoadjuvant setting.

A systematic review and meta-analysis of immune-mediated liver dysfunction in non-small cell lung cancer

BACKGROUND

Immune checkpoint inhibitors (ICIs) have been identified as validated medications in non-small cell lung cancer (NSCLC). However, they are often associated with immune-related adverse events (irAEs) including liver dysfunction. Therefore, we conducted a systematic review of the literature and performed a meta-analysis to ascertain overall incidence and risk of immune mediated liver dysfunction in NSCLC patients.

METHODS

PubMed, the Cochrane Library, Embase and ClinicalTrials.gov (http://clinicaltrials.gov/) were searched from inception to December 2019. Studies regarding all grade (1-5), high grade (3-5) hepatitis and ALT or AST elevation were included.

RESULTS

A total of 11 clinical trials including 7086 patients were selected for further assessment. The overall incidence of ALT elevation, AST elevation and hepatitis for the application of ICIs was 6.18%, 4.99% and 1.09%, respectively. Compared with chemotherapy group, treatment with ICIs had a significantly higher risk of all grade (RR: 7.27, p = 0.001) and high grade (RR: 6.70, p = 0.003) hepatitis. When ICIs combined with chemotherapy, the relative risk of all grade hepatitis was higher than monotherapy group (RR: 7.89, p = 0.044 vs RR: 6.94, p = 0.008).

CONCLUSION

The application of ICIs could result in a higher incidence and relative risk of all grade immune-induced liver dysfunction. Moreover, immunotherapy combined with chemotherapy may also increase relative risk of all grade hepatic AEs when compared with monotherapy. Prompt recognition and proper administration is required for clinicians to prevent potentially hepatic deterioration.

Association of tumour and stroma PD-1, PD-L1, CD3, CD4 and CD8 expression with DCB and OS to nivolumab treatment in NSCLC patients pre-treated with chemotherapy

BACKGROUND

Immune checkpoint inhibitors are most beneficial in patients with high tumour PD-L1 expression. However, the use of PD-L1 expression is not straightforward. We investigated PD-L1 expression and immune cell (IC) infiltrates in non-small-cell lung cancer (NSCLC) patients treated with nivolumab.

METHODS

Tumour tissue specimens of 139 NSCLC patients were scored for tumour/stromal PD-L1 and various IC expression markers, and associated with durable clinical benefit (DCB) and overall survival (OS).

RESULTS

Median OS was higher for patients with high stromal infiltration of CD8⁺ ICs (9.0 months) compared with patients with low and intermediate infiltration (both 5.0 months, p = 0.035) and for patients with high infiltration of stromal CD4⁺ ICs (9.0 months) compared with patients with low and intermediate infiltration (both 5.0 months, p = 0.010) and this was confirmed in the validation cohort. Post hoc analyses showed that biopsies taken after the last line of chemotherapy (ACT) were predictive for DCB and OS, whereas samples obtained before the last line of chemotherapy (BCT) were not.

CONCLUSIONS

Stromal infiltration of ICs can predict response to PD-1-directed immunotherapy in NSCLC patients. Interestingly, we found differences in the predictive value of IC markers between the ACT and BCT biopsies, suggesting that chemotherapy might influence the immune microenvironment.

Prognostic and clinical impact of PD-L2 and PD-L1 expression in a cohort of 437 oesophageal cancers

BACKGROUND

The PD-1/PD-L1 pathway plays critical roles in tumour immunology, and serves as an immune-based therapeutic target. Less is known regarding PD-L2, another ligand of PD-1, and its relation to clinical outcome in human cancers.

METHODS

We used a database of 437 surgically and 100 endoscopically resected oesophageal cancers (squamous cell carcinoma, n = 483; adenocarcinoma, n = 36; others, n = 18) to evaluate PD-L2 and PD-L1 expression by immunohistochemistry.

RESULTS

Compared with PD-L2-negative cases (n = 366, 83.8%), PD-L2-positive cases (n = 71, 16.2%) had worse overall survival (P = 0.011, log-rank test). There was not a significant correlation between PD-L2 and PD-L1 expression. Multiplex immunofluorescence revealed that there was variability in the expression pattern of PD-L2 and PD-L1. In early-stage tumours, PD-L2 expression was more frequently observed compared with PD-L1.

CONCLUSIONS

PD-L2 as well as PD-L1 were associated with an unfavourable prognosis in oesophageal cancer, supporting the role of PD-L2 as a prognostic biomarker. Considering that PD-L2 and PD-L1 had different features in terms of expression timing and responses to chemotherapeutic drugs, evaluation of both PD-L2 and PD-L1 expression may be clinically important.

5-FU-Induced Upregulation of Exosomal PD-L1 Causes Immunosuppression in Advanced Gastric Cancer Patients

Although the cytotoxic chemotherapeutic agent 5-fluorouracil (5-FU) is generally considered to directly kill cancer cells and exert immunostimulatory effects in advanced gastric cancer, accumulating evidence indicates that it upregulates the expression of PD-L1, a representative immune checkpoint blockade molecule involved in negative regulation of the immune response. It was reported that exosomes could transfer functional PD-L1 locally and distantly to suppress the antitumor immune response. However, whether 5-FU alters the expression of exosomal PD-L1 and induces immunosuppression in gastric cancer remains unclear. Herein, we found that 5-FU increased gastric cancer-derived exosomal PD-L1. Importantly, compared with baseline levels, circulating exosomal PD-L1 was significantly upregulated in 21 stage III–IV gastric cancer patients after two, four, and six repeated cycles of fluoropyrimidine treatment (P = 0.009, P = 0.047, and P = 0.023, respectively), accompanied by decreased amounts of IFN-γ, TNF-α, IL-2, IL-6, and GM-CSF (P = 0.014, P = 0.004, P = 0.009, P = 0.031, and P = 0.014, respectively). Additionally, circulating exosomal PD-L1 was increased more significantly in clinical non-responders compared with responders (P = 0.018). Furthermore, exosomal PD-L1 induced apoptosis in Jurkat T cells and inhibited T cell activation in PBMCs, which could be partly reversed by nivolumab. These results suggested that 5-FU-induced upregulation of exosomal PD-L1 causes systemic immunosuppression in advanced gastric cancer following multiple cycles of chemotherapy, especially after two cycles.

TENERGY: multicenter phase II study of Atezolizumab monotherapy following definitive Chemoradiotherapy with 5-FU plus Cisplatin in patients with unresectable locally advanced esophageal squamous cell carcinoma

BACKGROUND

The standard treatment for patients with unresectable locally advanced esophageal squamous cell carcinoma (ESCC) is definitive chemoradiotherapy (CRT) using 5-FU plus cisplatin. However, complete response (CR) rates are low at 11-25%, resulting in 9-10 months of median overall survival (OS). An improved therapeutic efficacy by combining immunotherapy with radiation has been reported in patients with locally advanced non-small cell lung cancer. The results using ESCC cell lines suggest sequential treatment with anti-PD-L1 agents soon after completion of CRT is the most effective combination.

METHODS

TENERGY trial is a multicenter, phase II, proof-of-concept study to assess the efficacy and safety of atezolizumab following definitive CRT in patients with locally advanced ESCC. The main inclusion criteria are unresectable locally advanced ESCC without distant metastasis, completion of 60 Gy of radiation plus two concomitant cycles of chemotherapy (cisplatin 70 mg/m2 on day 1 and 5-FU 700 mg/m2 on days 1-4, every 28 days), and adequate organ function. Within 6 weeks after CRT, participants will start taking 1200 mg of atezolizumab every three weeks and continue until 12 months or disease progression. The primary endpoint is the confirmed CR rate by the investigator's assessment. Secondary endpoints include overall response rate, progression-free survival (PFS), OS, adverse events, and confirmed CR rate by central assessment. We will enroll 50 patients (40 with primary locally advanced ESCC and 10 with postoperative locoregionally recurrent ESCC). We will obtain biopsies from the primary site and will collect blood at 3 time points (before CRT, after CRT, and four weeks after the start of atezolizumab) for an exploratory biomarker study. We will analyze the phenotype of immune-competent cells, neoantigens, tumor mutational burden, PD-L1 status, and Human Leukocyte Antigen haplotyping.

DISCUSSION

The synergistic efficacies of the sequential combination of CRT and atezolizumab should improve the CR rate, resulting in survival improvement for patients with unresectable locally advanced ESCC. Because CRT is a standard treatment option for patients with early stage to locally advanced ESCC, the sequential combination of CRT and atezolizumab has the potential to change the standard ESCC treatments.

TRIAL REGISTRATION

UMIN000034373, 10/04/2018 and EPOC1802.

Anti-tumour immune response in GL261 glioblastoma generated by Temozolomide Immune-Enhancing Metronomic Schedule monitored with MRSI-based nosological images

Glioblastomas (GB) are brain tumours with poor prognosis even after aggressive therapy. Improvements in both therapeutic and follow-up strategies are urgently needed. In previous work we described an oscillatory pattern of response to Temozolomide (TMZ) using a standard administration protocol, detected through MRSI-based machine learning approaches. In the present work, we have introduced the Immune-Enhancing Metronomic Schedule (IMS) with an every 6-d TMZ administration at 60 mg/kg and investigated the consistence of such oscillatory behaviour. A total of n = 17 GL261 GB tumour-bearing C57BL/6j mice were studied with MRI/MRSI every 2 d, and the oscillatory behaviour (6.2 ± 1.5 d period from the TMZ administration day) was confirmed during response. Furthermore, IMS-TMZ produced significant improvement in mice survival (22.5 ± 3.0 d for controls vs 135.8 ± 78.2 for TMZ-treated), outperforming standard TMZ treatment. Histopathological correlation was investigated in selected tumour samples (n = 6) analyzing control and responding fields. Significant differences were found for CD3+ cells (lymphocytes, 3.3 ± 2.5 vs 4.8 ± 2.9, respectively) and Iba-1 immunostained area (microglia/macrophages, 16.8% ± 9.7% and 21.9% ± 11.4%, respectively). Unexpectedly, during IMS-TMZ treatment, tumours from some mice (n = 6) fully regressed and remained undetectable without further treatment for 1 mo. These animals were considered "cured" and a GL261 re-challenge experiment performed, with no tumour reappearance in five out of six cases. Heterogeneous therapy response outcomes were detected in tumour-bearing mice, and a selected group was investigated (n = 3 non-responders, n = 6 relapsing tumours, n = 3 controls). PD-L1 content was found ca. 3-fold increased in the relapsing group when comparing with control and non-responding groups, suggesting that increased lymphocyte inhibition could be associated to IMS-TMZ failure. Overall, data suggest that host immune response has a relevant role in therapy response/escape in GL261 tumours under IMS-TMZ therapy. This is associated to changes in the metabolomics pattern, oscillating every 6 d, in agreement with immune cycle length, which is being sampled by MRSI-derived nosological images.

Pemetrexed Enhances Membrane PD-L1 Expression and Potentiates T Cell-Mediated Cytotoxicity by Anti-PD-L1 Antibody Therapy in Non-Small-Cell Lung Cancer

Immunotherapy has significantly changed the treatment landscape for advanced non-small-cell lung cancer (NSCLC) with the introduction of drugs targeting programmed cell death protein-1 (PD-1) and programmed cell death ligand-1 (PD-L1). In particular, the addition of the anti-PD-1 antibody pembrolizumab to platinum-pemetrexed chemotherapy resulted in a significantly improved overall survival in patients with non-squamous NSCLC, regardless of PD-L1 expression. In this preclinical study, we investigated whether chemotherapy can modulate PD-L1 expression in non-squamous NSCLC cell lines, thus potentially affecting immunotherapy efficacy. Among different chemotherapeutic agents tested, only pemetrexed increased PD-L1 levels by activating both mTOR/P70S6K and STAT3 pathways. Moreover, it also induced the secretion of cytokines, such as IFN-γ and IL-2, by activated peripheral blood mononuclear cells PBMCs that further stimulated the expression of PD-L1 on tumor cells, as demonstrated in a co-culture system. The anti-PD-1/PD-L1 therapy enhanced T cell-mediated cytotoxicity of NSCLC cells treated with pemetrexed and expressing high levels of PD-L1 in comparison with untreated cells. These data may explain the positive results obtained with pemetrexed-based chemotherapy combined with pembrolizumab in PD-L1-negative NSCLC and can support pemetrexed as one of the preferable chemotherapy partners for immunochemotherapy combination regimens.

Combined cytotoxic chemotherapy and immunotherapy of cancer: modern times

Monoclonal antibodies targeting programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) immune checkpoints have improved the treatments of cancers. However, not all patients equally benefit from immunotherapy. The use of cytotoxic drugs is practically inevitable to treat advanced cancers and metastases. The repertoire of cytotoxics includes 80 products that principally target nucleic acids or the microtubule network in rapidly proliferating tumor cells. Paradoxically, many of these compounds tend to become essential to promote the activity of immunotherapy and to offer a sustained therapeutic effect. We have analyzed each cytotoxic drug with respect to effect on expression and function of PD-(L)1. The major cytotoxic drugs—carboplatin, cisplatin, cytarabine, dacarbazine, docetaxel, doxorubicin, ecteinascidin, etoposide, fluorouracil, gemcitabine, irinotecan, oxaliplatin, paclitaxel and pemetrexed—all have the capacity to upregulate PD-L1 expression on cancer cells (via the generation of danger signals) and to promote antitumor immunogenicity, via activation of cytotoxic T lymphocytes, maturation of antigen-presenting cells, depletion of immunosuppressive regulatory T cells and/or expansion of myeloid-derived suppressor cells. The use of ‘immunocompatible’ cytotoxic drugs combined with anti-PD-(L)1 antibodies is a modern approach, not only for increasing the direct killing of cancer cells, but also as a strategy to minimize the activation of immunosuppressive and cancer cell prosurvival program responses.

PD-1/PD-L1-dependent immune response in colorectal cancer

Colorectal cancer (CRC) is still considered as the third most frequent cancer in the world. Microsatellite instability (MSI), inflammation, and microRNAs have been demonstrated as the main contributing factors in CRC. Subtype 1 CRC is defined by NK cells infiltration, induction of Th1 lymphocyte and cytotoxic T cell responses as well as upregulation of immune checkpoint proteins including programmed cell death-1 (PD-1). Based on the diverse features of CRC, such as the stage and localization of the tumor, several treatment approaches are available. However, the efficiency of these treatments may be decreased due to the development of diverse resistance mechanisms. It has been proven that monoclonal antibodies (mAbs) can increase the effectiveness of CRC treatments. Nowadays, several mAbs including nivolumab and pembrolizumab have been approved for the treatment of CRC. Immune checkpoint receptors including PD-1 can be inhibited by these antibodies. Combination therapy gives an opportunity for advanced treatment for CRC patients. In this review, an update has been provided on the molecular mechanisms involved in MSI colorectal cancer immune microenvironment by focusing on PD-ligand 1 (PD-L1) and treatment of patients with advanced immunotherapy, which were examined in the different clinical trial phases. Considering induced expression of PD-L1 by conventional chemotherapeutics, we have summarized the role of PD-L1 in CRC, the chemotherapy effects on the PD-1/PD-L1 axis and novel combined approaches to enhance immunotherapy of CRC by focusing on PD-L1.

Immune Checkpoint Imaging in Oncology: A Game Changer Toward Personalized Immunotherapy?

Immune checkpoint blockade represents a promising approach in oncology, showing antitumor activities in various cancers. However, although being generally far better tolerated than classic cytotoxic chemotherapy, this treatment, too, may be accompanied by considerable side effects and not all patients benefit equally. Therefore, careful patient selection and monitoring of the treatment response is mandatory. At present, checkpoint-specific molecular imaging is being increasingly investigated as a tool for patient selection and response evaluation. Here, an overview of the current developments in immune checkpoint imaging is provided.

Amplifying Outcomes: Checkpoint Inhibitor Combinations in First-Line Non-Small Cell Lung Cancer

PURPOSE

Lung cancer is one of the most common types of cancer, resulting in approximately 1.8 million deaths worldwide. Immunotherapy using checkpoint inhibitors has become standard of care in advanced non-small cell lung cancer (NSCLC), and there is increasing interest in further improving outcomes through combination with other therapeutics. This systematic review evaluates emerging phase III data on the efficacy and safety of checkpoint inhibitor combinations as first-line treatment for advanced NSCLC.

MATERIALS AND METHODS

Published and presented literature was searched using the key search terms "non-small cell lung cancer" AND "checkpoint-inhibitors" (OR respective aliases) AND phase III trials. Seven randomized phase III clinical trials reporting outcomes on checkpoint inhibitor combinations in first-line advanced NSCLC were identified.

RESULTS

Four first-line trials reported outcomes for checkpoint inhibitor combinations in nonsquamous NSCLC. Pembrolizumab-chemotherapy, atezolizumab-chemotherapy, and atezolizumab-bevacizumab-chemotherapy showed significantly improved overall survival compared with controls in patients with advanced nonsquamous epidermal growth factor receptor-negative (EGFR-)/ anaplastic lymphoma kinase gene (ALK)- NSCLC. Two trials reported outcomes for squamous NSCLC, with pembrolizumab-chemotherapy reporting significantly improved overall survival (OS) compared with chemotherapy. The combination of nivolumab-ipilimumab in all-comer histology failed to improve OS compared with histology appropriate chemotherapy in patients regardless of their tumor mutational burden status. Based on improved survival and safety, either pembrolizumab monotherapy or pembrolizumab-chemotherapy administered based on PD-L1 status and histology is a preferred treatment option. Outcomes for atezolizumab-bevacizumab-chemotherapy in EGFR+/ALK+ patients are promising and require further exploration.

CONCLUSION

First-line checkpoint inhibitors added to standard therapies improve overall survival for nonsquamous EGFR-/ALK- and squamous advanced NSCLC.

IMPLICATIONS FOR PRACTICE

Single-agent immune checkpoint inhibitors are now standard of care for advanced non-small cell lung cancer (NSCLC), and emerging data show that combining these agents with established chemotherapy further improves outcomes. The phase III KEYNOTE-189 and IMPower-130 trials showed significantly improved survival using this strategy for nonsquamous NSCLC, and the phase III KEYNOTE-407 trial showed similar results in squamous disease. Checkpoint inhibitor combinations are therefore an important new treatment option for first-line NSCLC. Programmed death ligand-1 expression may inform the use of checkpoint inhibitor combination therapy, and overall tumor mutation burden is also an emerging biomarker for this new treatment strategy.

Therapy Resistance in Neoadjuvantly Treated Gastric Cancer and Cancer of the Gastroesophageal Junction is Associated with an Increased Expression of Immune Checkpoint Inhibitors-Comparison Against a Therapy Naïve Cohort

With recent studies uncovering the complex landscape of immune checkpoint regulators in gastric cancer (GC), we aimed to characterize the expression of the checkpoint proteins V-domain Ig suppressor of T-cell activation (VISTA), programmed cell death 1 ligand 1 (PD-L1), and programmed cell death protein-1 (PD-1) in a cohort of GCs following platinum-based neoadjuvant chemotherapy. A total of 141 GC samples, 93 lymph node metastases, and 15 distant metastases were assessed using immunohistochemistry. Staining results were correlated with clinicopathological patient characteristics, genetic alterations, and survival. The expression of VISTA was detected in tumor cells of 38 (30.9%) GCs and immune cells of 139 (98.6%) GCs. The expression of PD-L1 was detected in tumor cells of 27 (22.7%) GCs and immune cells of 134 (96.4%) GCs. The expression of PD-1 was only observed in lymphocyte aggregates/intratumoral lymphoid follicles of 123 (87.2%) GCs. VISTA and PD-L1 correlated in their expression and were associated with poor tumor regression. Compared with an ancient cohort of therapy naïve GCs, we observed a major increase in overall immune cell density accompanied by an over proportional increase in PD-1 and VISTA-positive immune cells. The frequency of VISTA expression in tumor cells was also found to be substantially increased. To the contrary, expression of PD-L1 was decreased in immune cells and tumor cells of neoadjuvantly treated GCs. As a result, a subset of GCs using a single (only VISTA or PD-L1) or combined (VISTA and PD-L1) immune evasion mechanisms might benefit from an anti-PD-L1/anti-VISTA–targeted therapy.

Combination of pembrolizumab and BCG treatment after endoscopic ablation of high-risk superficial upper urinary tract urothelial carcinoma in patients not candidates for radical nephroureterectomy: protocol for phase-II study

INTRODUCTION

The treatment standard for high-risk upper urinary tract urothelial carcinoma (UUTUC) is radical nephroureterectomy. However, some patients may be unfit or unwilling, and in such patients the available alternatives are suboptimal. Therapies targeting the programmed death (PD) pathway have shown promise in urothelial carcinom (UC). We designed the current study to determine the safety and efficacy of administering MK-3475 (a monoclonal antibody targeting interaction between PD-1 and its ligand) in combination with bacillus Calmette-Guerin (BCG) in high-risk non-muscle invasive UUTUC patients.

METHODS

This represents a single-centre phase-II efficacy study of MK-3475 therapy in combination with BCG for subjects, 18 years of age or older, with pathologically documented non-muscle invasive high-risk UUTUC unfit or unwilling to be treated with radical nephroureterectomy. Twenty subjects will be enrolled; patients will receive treatment with 200 mg of MK-3475 every 21 days, starting 2 weeks from the initial endoscopic resection and continuing for 6 weeks after the final dose of BCG. The primary objective is to determine the safety and efficacy of administering MK-3475 at a fixed dose of 200 mg every 3 weeks in conjunction with intrapelvic BCG. Secondary objectives include 19 week and the 3, 12 and 24-month post-treatment completion complete response and progression-free rate assessments.

ETHICS AND DISSEMINATION

The study has been approved by the Institutional Review Board of the Henry Ford Hospital. The results of this study will be published in a peer-reviewed journal and presented at a scientific conference.

TRIAL REGISTRATION NUMBER

NCT03345134.

Drug-induced PD-L1 expression and cell stress response in breast cancer cells can be balanced by drug combination

The impact of chemotherapy on tumor-immune system interaction can be either beneficial or harmful, which is represented by the immunogenic cell death (ICD) paradigm or overexpression of the immunosuppressive protein – programmed death ligand 1 (PD-L1). In this study we explore the impact of steroid receptor coactivator inhibitor, other targeted anti-cancer compounds and traditional chemotherapeutic agents on the expression of PD-L1 in four breast cancer (BC) cell lines. Our results show that these agents induce PD-L1 expression, yet the magnitude of this induction varies substantially across the different compounds. In addition, we utilized the E0771 ER + BC cells as a model to examine in greater detail the relationship between pharmacological pressure, cell stress and the induction of PD-L1. Our results imply that drug induced PD-L1 expression occurs in the broader context of cell-stress, without conferring acquired drug-resistance. Furthermore, a balance between BC cytotoxicity, induction of cell-stress and the overexpression of PD-L1 can be achieved through the selection of appropriate combinations of anti-cancer compounds. Therefore, we propose that drug combination can be employed not only for increasing the direct kill of cancer cells, but also as a strategy to minimize the activation of immunosuppressive and cancer cell pro-survival program responses during drug treatment.

A Designer Scaffold with Immune Nanoconverters for Reverting Immunosuppression and Enhancing Immune Checkpoint Blockade Therapy

Current cancer immunotherapy based on immune checkpoint blockade (ICB) still suffers from low response rate and systemic toxicity. To overcome the limitation, a novel therapeutic platform that can revert nonimmunogenic tumors into immunogenic phenotype is highly required. Herein, a designer scaffold loaded with both immune nanoconverters encapsulated with resiquimod (iNCVs (R848)) and doxorubicin, which provides the polarization of immunosuppressive tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) into tumoricidal antigen-presenting cells (APCs), rather than depleting them, as well as in situ vaccination that can be generated in vivo without the need to previously analyze and sequence tumor antigens to favor neoantigen-specific T cell responses is suggested. Local and sustained release of iNCVs (R848) and doxorubicin from the designer scaffold not only reduces the frequency of immunosuppressive cells in tumors but also increases systemic antitumor immune response, while minimizing systemic toxicity. Reshaping the tumor microenivronment (TME) using the designer-scaffold-induced synergistic antitumor immunity with ICB effects and long-term central and effector memory T cell responses, results in the prevention of postsurgical tumor recurrence and metastasis. The spatiotemporal modulation of TMEs through designer scaffolds is expected to be a strategy to overcome the limitations and improve the therapeutic efficacy of current immunotherapies with minimized systemic toxicity.

In situ formed reactive oxygen species-responsive scaffold with gemcitabine and checkpoint inhibitor for combination therapy

Patients with low-immunogenic tumors respond poorly to immune checkpoint blockade (ICB) targeting the programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) pathway. Conversely, patients responding to ICB can experience various side effects. We have thus engineered a therapeutic scaffold that, when formed in situ, allows the local release of gemcitabine (GEM) and an anti-PD-L1 blocking antibody (aPDL1) with distinct release kinetics. The scaffold consists of reactive oxygen species (ROS)-degradable hydrogel that releases therapeutics in a programmed manner within the tumor microenvironment (TME), which contains abundant ROS. We found that the aPDL1-GEM scaffold elicits an immunogenic tumor phenotype and promotes an immune-mediated tumor regression in the tumor-bearing mice, with prevention of tumor recurrence after primary resection.

A phase II study of pembrolizumab and paclitaxel in patients with relapsed or refractory small-cell lung cancer

OBJECTIVE

Patients with etoposide/platinum-refractory extensive disease (ED) small-cell lung cancer (SCLC) have a dismal prognosis. We aimed to evaluate the efficacy and safety of pembrolizumab and paclitaxel combination therapy in these patients.

METHODS

In this multi-center, phase II study, ED-SCLC patients who showed progression after etoposide/platinum chemotherapy received paclitaxel 175 mg/m² every 3 weeks for up to six cycles. Pembrolizumab 200 mg was added from the second cycle and continued until disease progression or unacceptable toxicity. The primary endpoint was the objective response rate (ORR) and the secondary endpoints were progression-free survival (PFS), overall survival (OS), safety, and biomarker analyses including programmed death-ligand 1 (PD-L1) expression, next-generation sequencing, and flow cytometric analysis of peripheral blood cells.

RESULTS

Of the 26 patients enrolled, the confirmed ORR was 23.1% (95%CI: 6.9%-39.3%); complete response: 3.9%, confirmed partial response [PR]: 19.2%, stable disease: 57.7%, progressive disease: 7.7%, and not evaluable: 11.5%. Including 4 cases of unconfirmed PRs, 38.5% of patients were responding and the disease control rate was 80.7%. The median PFS and OS were 5.0 months (95% CI: 2.7-6.7) and 9.1 months (95% CI: 6.5-15.0), respectively. The grade 3 or 4 adverse events observed included febrile neutropenia (7.7%), neutropenia (7.7%), asthenia (7.7%), hyponatremia (7.7%), and type I diabetes (7.7%). Targeted gene sequencing identified no specific genetic alterations correlated with the treatment, except for theMET copy number gain (PFS 10.5 versus 3.4 months, p = 0.019).

CONCLUSIONS

Pembrolizumab and paclitaxel combination therapy showed a moderate activity with acceptable toxicity in patients with refractory ED-SCLC.

Building a Bridge between Chemotherapy and Immunotherapy in Malignant Pleural Mesothelioma: Investigating the Effect of Chemotherapy on Immune Checkpoint Expression

In light of the promising results of immune checkpoint blockade (ICPB) in malignant pleural mesothelioma (MPM), we investigated the effect of different chemotherapeutic agents on the expression of immune checkpoints (ICPs) in order to rationally design a good treatment schedule for their combination with ICP blocking antibodies. Cisplatin, oxaliplatin and pemetrexed are interesting chemotherapeutic agents to combine with immunotherapy given their immunomodulatory capacities. We looked into cisplatin and pemetrexed because their combination is used as first-line treatment of MPM. Additionally, the effect of the immunogenic chemotherapeutic agent, oxaliplatin, was also studied. Three different MPM cell lines were used for representation of both epithelioid and sarcomatoid subtypes. The desired inhibitory concentrations of the chemotherapeutic agents were determined with the SRB-assay. Allogeneic co-cultures of MPM cells with healthy donor peripheral blood mononuclear cells (PBMC) were set up to assess the effect of these chemotherapeutic agents on the expression of ICPs (PD-1, LAG-3, TIM-3) and their ligands (PD-L1, PD-L2, galectin-9). Cisplatin might be a promising treatment to combine with ICP blocking antibodies since our MPM cell lines were most susceptible to this stand-alone treatment. We found that the expression of ICPs and their ligands on both MPM cells and PBMC was mostly downregulated or unaltered when treated with chemotherapeutic agents, though no clear trend could be determined.

DHA-SBT-1214 Taxoid Nanoemulsion and Anti-PD-L1 Antibody Combination Therapy Enhances Antitumor Efficacy in a Syngeneic Pancreatic Adenocarcinoma Model

The goal of this study was to evaluate combination of a novel taxoid, DHA-SBT-1214 chemotherapy, in modulating immune checkpoint marker expression and ultimately in improving antibody-based checkpoint blockade therapy in pancreatic adenocarcinoma (PDAC). DHA-SBT-1214 was encapsulated in an oil-in-water nanoemulsion and administered systemically in Panc02 syngeneic PDAC-bearing C57BL/6 mice. Following treatment with DHA-SBT-1214, expression levels of PD-L1 were measured and anti-PD-L1 antibody was administered in combination. The effects of combination therapy on efficacy and the molecular basis of synergistic effects were evaluated. PD-L1 expression was lower on Panc02 pancreatic tumor cells in vitro, which significantly increased after exposure to different chemotherapy drugs. Administration of DHA-SBT-1214, gemcitabine, and PD-L1 antibody alone failed to increase CD8⁺ T-cell infiltration inside tumors. However, combination of anti-PD-L1 therapy with a novel chemotherapy drug DHA-SBT-1214 in nanoemulsion (NE-DHA-SBT-1214) significantly enhanced CD8⁺ T-cell infiltration and the therapeutic effects of the anti-PD-L1 antibody. Furthermore, in the Panc02 syngeneic model, the NE-DHA-SBT-1214 combination therapy group reduced tumor growth to a higher extend than paclitaxel, nab-paclitaxel (Abraxane), gemcitabine, or single anti-PD-L1 antibody therapy groups. Our results indicate that NE-DHA-SBT-1214 stimulated immunogenic potential of PDAC and provided an enhanced therapeutic effect with immune checkpoint blockade therapy, which warrants further evaluation.

National Cancer Institute (NCI) state of the science: Targeted radiosensitizers in colorectal cancer

Colorectal cancer (CRC) represents a major public health problem as the second leading cause of cancer-related mortality in the United States. Of an estimated 140,000 newly diagnosed CRC cases in 2018, roughly one-third of these patients will have a primary tumor located in the distal large bowel or rectum. The current standard-of-care approach includes curative-intent surgery, often after preoperative (neoadjuvant) radiotherapy (RT), to increase rates of tumor down-staging, clinical and pathologic response, as well as improving surgical resection quality. However, despite advancements in surgical techniques, as well as sharpened precision of dosimetry offered by contemporary RT delivery platforms, the oncology community continues to face challenges related to disease relapse. Ongoing investigations are aimed at testing novel radiosensitizing agents and treatments that might exploit the systemic antitumor effects of RT using immunotherapies. If successful, these treatments may usher in a new curative paradigm for rectal cancers, such that surgical interventions may be avoided. Importantly, this disease offers an opportunity to correlate matched paired biopsies, radiographic response, and molecular mechanisms of treatment sensitivity and resistance with clinical outcomes. Herein, the authors highlight the available evidence from preclinical models and early-phase studies, with an emphasis on promising developmental therapeutics undergoing prospective validation in larger scale clinical trials. This review by the National Cancer Institute's Radiation Research Program Colorectal Cancer Working Group provides an updated, comprehensive examination of the continuously evolving state of the science regarding radiosensitizer drug development in the curative treatment of CRC.

[Predictive value of PD-L1 diagnostics]

Immuno-oncology related treatments have become standard of care for many tumor entities. Numerous additional indications are currently under investigation in ongoing clinical trials. Predictive biomarkers include microsatellite instability as well as tumor mutational burden. However, PD-L1 testing by immunohistochemistry (IHC) is already widely established as a biomarker in clinical routine for certain treatment decisions in non-small cell lung cancer, head and neck cancer and in urothelial carcinomas. More applications of that kind are expected to follow. Moreover, PD-L1 testing can provide clinicians with valuable information even if the test is not mandatory (i. e., complementary diagnostics). PD-L1 staining requires a highly specific staining over a broad dynamic range. Sensitive and specific primary antibodies and suitable staining protocols are prerequisite. Selection of appropriate patients' materials, validation and contiguous quality assurance need to meet the highest standards. There are different scoring algorithms for PD-L1 stainings which are specific to tumor entities and certain clinical decisions. The tumor proportion score (TPS) is a PD-L1 measurement which is applied, for example, to lung cancer, head and neck cancer and melanomas. Within this approach, only membranous staining of tumor cells is regarded as a significant staining. In contrast, the combined positivity score (CPS) and inflammatory cell (IC) scoring include or are restricted to PD-L1 expression in certain inflammatory cells, respectively. CPS and IC scoring are standard measurements of PD-L1 in urothelial carcinoma.

Alteration in tumoural PD-L1 expression and stromal CD8-positive tumour-infiltrating lymphocytes after concurrent chemo-radiotherapy for non-small cell lung cancer

Background

Consolidation treatment with an anti-PD-L1 antibody, durvalumab, following concurrent chemo-radiotherapy (cCRT) has become a new standard of care for locally advanced non-small cell lung cancer (NSCLC). The rationale of PD-L1 blockade after cCRT is based on preclinical evidence suggesting that chemotherapy and radiotherapy up-regulate tumoural PD-L1 expression, which has not been shown in clinical studies.

Methods

To examine alteration in tumoural PD-L1 expression (tumour proportion score, TPS) and density of stromal CD8-positive tumour-infiltrating lymphocytes (CD8 + TILs) after cCRT, paired NSCLC samples obtained before and after cCRT were reviewed in comparison with those obtained before and after drug therapy.

Results

PD-L1 expression was significantly up-regulated after cCRT (median TPS, 1.0 at baseline versus 48.0 after cCRT; P < 0.001), but not after drug therapy. There was no significant correlation between baseline TPS and post-cCRT TPS. CD8 + TIL density was significantly increased after cCRT (median, 10.6 versus 39.1; P < 0.001), and higher post-cCRT CD8 + TIL density was associated with a higher pathologic response and with a favourable survival (P = 0.019).

Conclusion

Tumoural PD-L1 expression was up-regulated after cCRT, which provides pathologic rationale for PD-L1 blockade following cCRT to improve prognosis. Stromal CD8 + TIL density was also increased after cCRT, and higher post-cCRT CD8 + TIL density was a favourable prognostic indicator.

Protocol for phase I study of pembrolizumab in combination with Bacillus Calmette-Guérin for patients with high-risk non-muscle invasive bladder cancer

INTRODUCTION

The initial treatment for high-risk non-muscle invasive bladder cancer (NMIBC) is endoscopic resection of the tumour followed by BCG therapy. In those who develop recurrence, the standard treatment is radical cystectomy. Despite the advancement in surgical technique and postoperative care, the degree of morbidity associated with radical cystectomy remains high, therefore less invasive treatment modalities are desirable. Therapies targeting the programmed death (PD) pathway have shown promise in urothelial carcinoma. We undertook the current study to determine the safety and efficacy of administering pembrolizumab (a monoclonal antibody targeting the interaction between PD-1 and its ligand) in combination with BCG in high-risk NMIBC.

METHODS

This is a single-centre phase I safety and efficacy study of pembrolizumab used in combination with intravesicular BCG treatment for subjects with pathologically documented high-risk NMIBC despite having received two courses of induction therapy or BCG treatment followed by maintenance BCG. Fifteen subjects will be enrolled, patients will receive treatment with 200 mg of pembrolizumab every 21 days, starting 2 weeks from the initial endoscopic resection and continuing for 6 weeks after the final dose of BCG. The primary objective is to determine the safety of administering pembrolizumab at a fixed dose of 200 mg every 3 weeks in conjunction with intravesicular BCG treatment in patients with high-risk NMIBC who have failed previous treatment. Secondary objectives are to determine the 19 weeks and the 3, 12 and 24 months post-treatment completion complete response rate with combined pembrolizumab and intravesicular BCG therapy in the aforementioned patients.

ETHICS AND DISSEMINATION

The study has been approved by the Institutional Review Board of the Henry Ford Hospital. The results of this study will be published in a peer-reviewed journal and presented at a scientific conference.

TRIAL REGISTRATION NUMBER

NCT02324582.

Monitoring the Response of PD-L1 Expression to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Nonsmall-Cell Lung Cancer Xenografts by Immuno-PET Imaging

Accumulating evidence has suggested that the tumor microenvironment of nonsmall-cell lung cancer (NSCLC) may be impacted by chemotherapy, radiotherapy, or epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). PD-L1 is an important biomarker in the tumor microenvironment that can predict patient response to immunotherapies. Therefore, it is highly desirable to achieve a real-time, noninvasive assessment of PD-L1 expression, which can provide critical information for recruiting patients as well as monitoring therapeutic efficacy. We herein studied the EGFR-TKI-induced effects on PD-L1 levels in NSCLC tumor models using immuno-PET imaging with ⁸⁹Zr-Df-KN035, an imaging tracer previously established by our group. A549 human NSCLC xenografts were established in BALB/c nude mice and treated with different doses of an EGFR-TKI gefitinib. PET imaging with ⁸⁹Zr-Df-KN035 was performed before and after the treatment to evaluate PD-L1 expression, which was further verified by immunohistochemical staining. Our results demonstrate that ⁸⁹Zr-Df-KN035 can specifically evaluate PD-L1 levels in NSCLC tumor models. Compared to the untreated control, the high dose of gefitinib inhibited tumor growth and lowered the tumor uptake of ⁸⁹Zr-Df-KN035. In comparison, the low dose of gefitinib did not affect tumor growth, although the extensive tumor necrosis also led to the lower uptake of ⁸⁹Zr-Df-KN035. In conclusion, our results demonstrate that immuno-PET imaging with ⁸⁹Zr-Df-KN035 is a promising tool to noninvasively monitor PD-L1 expression in NSCLC treated with EGFR-TKIs and can be used to optimize treatment plans for immunotherapy.