Immune-Related Tumor Response Dynamics in Melanoma Patients Treated with Pembrolizumab: Identifying Markers for Clinical Outcome and Treatment Decisions

Pooled Rate of Pseudoprogression, Patterns of Response, and Tumor Burden Analysis in Patients Undergoing Immunotherapy Oncologic Trials for Different Malignancies

AIMS

Assess rates of true pseudoprogression in unconfirmed progressive disease (iUPD) in a pool of immunotherapy clinical trials for different cancers, analyze tumor characteristics that drive iUPD classification, and investigate potentials predictors of pseudoprogression.

MATERIALS AND METHODS

Retrospective interpretation of prospectively acquired data. Patients from 18 immunotherapy clinical trials with two arms (RECIST 1.1, iRECIST), of 10 cancer types were selected. Pooled rate of true pseudoprogression among iUPD was estimated using a common effect meta-analysis. Target, Non-target, and new lesions as the trigger of confirmed-vs pseudo-progression were compared using Chi-Square and Fisher exact tests. Conditional logistic regression was used to investigate the association between age, sex, tumor burden at baseline, and number of follow ups and pseudoprogression.

RESULTS

60/287 (21%) patients (17 women) were classified as iUPD with at least one subsequent confirmatory timepoint. The overall pooled estimate of pseudoprogression was 15% (95%CI: 8%--26%). Nontarget lesions were significantly more frequent the cause of iUPD than change in Target lesions size (p< 0.001). Most observations of true pseudoprogression occurred in the first follow-up (77%), whereas confirmed progression occurred in later time points during the trial. Pseudoprogression was not significantly associated with age, sex, tumor burden at baseline, or number of timepoints.

CONCLUSION

In a pool of immunotherapy trials, the rate of true pseudoprogression was 15%, most often in the first timepoint after baseline than later in treatment. iUPD categorization was mostly driven by changes in NT lesions rather than objective changes in measurements of target lesions.

Genomic and molecular alterations associated with primary resistance to immune checkpoint inhibitors

The clinical response to immune checkpoint inhibitors may vary by tumor type and many tumors present with either primary or acquired resistance to immunotherapy. Improved understanding of the molecular and immunologic mechanisms underlying immunotherapy resistance is essential for developing biomarkers and for guiding the optimum approach to selecting treatment regimens and sequencing. This is increasingly important for tumors with primary resistance as effective biomarkers in this setting can guide clinicians about appropriate treatment regimen selection in the first-line setting. Multiple potential biological mechanisms of primary resistance have been proposed but most are yet to be validated in prospective clinical cohorts. Individual biomarkers have poor specificity and sensitivity, and the development of validated and integrated predictive models may guide which patient will benefit from monotherapy versus combination therapy. In this review, we discuss the emerging data identifying the molecular mechanisms of primary resistance to immunotherapy and explore potential therapeutic strategies to target these.

Utility of Assessing Early Tumor Shrinkage as an Efficacy Predictor in Patients with Non-Surgically Indicated or Recurrent Esophageal Cancer Treated with Nivolumab plus Ipilimumab

INTRODUCTION

Nivolumab plus ipilimumab combination therapy has been administered as a first-line treatment in Japan since 2022 for patients with unresectable progressive or recurrent esophageal cancer. The efficacy and safety of this immune checkpoint inhibitor (ICI) doublet therapy are now being evaluated, and it is necessary to identify populations that benefit from this treatment at an early phase after initiation. For patients not showing early benefit, changing as soon as possible to other therapeutic strategies could improve their survival outcomes. Therefore, we attempted to identify decision-making factors such as early tumor shrinkage (ETS) based on treatment experience with ICI doublet therapy.

METHODS

The study included 19 patients who received nivolumab plus ipilimumab for non-surgically indicated or recurrent esophageal cancer between July 2022 and November 2023. Tumors were assessed approximately every 2 months after treatment initiation. The effects of ETS, depth of response (DpR), and clinicopathologic features, including immune-related adverse events (irAEs), on progression-free and overall survival were evaluated using Kaplan-Meier plots and Cox proportional hazard models.

RESULTS

The mean duration of ICI doublet administration was 5.89 months (range, 1-16 months). At first evaluation, patients who exhibited no tumor progression >20% indicated possible response to ICI doublet therapy, and patients whose tumors shrank even minimally exhibited favorable progression-free survival. Higher DpR at any cut-off line exhibited better progression-free survival than those with lower DpR. Fifteen patients experienced irAEs, with 13 of these patients experiencing irAEs within 3 months of treatment initiation. irAEs were associated with the efficacy of ICI doublet therapy, but efficacy could not be predicted based on early irAE experience.

CONCLUSION

ETS-high, DpR-high, and irAEs might be associated with favorable responses to nivolumab plus ipilimumab. As a predictor of efficacy at an early phase, ETS >0% could be a deciding factor for continuing ICI doublet therapy.

[Advances in Pseudoprogression of Immune Checkpoint Inhibitors in Non-small Cell Lung Cancer]

The advent of immune checkpoint inhibitors (ICIs) has greatly improved the prognosis of advanced lung cancer patients, but can lead to pseudoprogression (PsP), which complicates clinical evaluation and management. PsP is manifested as temporary enlargement of the tumour or the appearance of new lesions, etc., and improvement in imaging occurs with continued treatment, mostly without worsening of clinical symptoms. Currently, there are still difficulties in the early diagnosis of PsP, and its occurrence mechanism is not yet clear, lacking good predictive factors and related biomarkers. This article reviews the current research status of PsP of ICIs in non-small cell lung cancer in order to provide helpful clinical strategies for oncologists using these drugs.
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Renal-clearable nanoprobes for optical imaging and early diagnosis of diseases

Optical imaging has played an indispensable role in clinical diagnostics and fundamental biomedical research due to its high sensitivity, high spatiotemporal resolution, cost-effectiveness, and easy accessibility. However, the issues of light scattering and low tissue penetration make them effective only for superficial imaging. To overcome these issues, renal-clearable optical nanoprobes have recently emerged, which are activated by abnormal disease-associated biomarkers and initiate a pharmacokinetic switch by undergoing degradation and eventually releasing signal reporters into urine, for simple imaging and sensitive optical in vitro urinalysis. In this review, we focus on the advancements of renal-clearable organic nanoprobes for optical imaging and remote urinalysis. The versatile design strategies of these nanoprobes are discussed along with their sensing mechanisms toward biomolecules of interest as well as their unique biological applications. Finally, challenges and perspectives are discussed to further advance the next-generation renal-clearable nanoprobes for in vivo imaging and in vitro urinalysis.

Progress in the research of immunotherapy‑related hyperprogression (Review)

Immunotherapy has become an effective method for the treatment of a variety of malignant tumors. However, with the development of immunotherapy, the phenomenon of hyperprogression in patients with cancer has gradually attracted attention. Hyperprogression refers to a condition in which the progression of a disease during treatment of a patient with cancer is suddenly accelerated. To date, no reliable marker has been found to predict accelerated tumor growth during immune checkpoint inhibitor (ICI) treatment. The aim the present study was to summarize the definition of hyperprogression and the difference between hyperprogression and pseudocytosis, and investigate the potential mechanisms of hyperprogression including clinical characteristics, potential molecular markers and the immune microenvironment. The effect of macrophage-related different types and factors on tumors in the immune microenvironment was analyzed, and the findings may be used to determine the future directions of research in hyperprogression.

Advanced non-small-cell lung cancer treated with first-line pembrolizumab plus chemotherapy: tumor response dynamics as a marker for survival

OBJECTIVES

The study investigated tumor burden dynamics on computed tomography (CT) scans in patients with advanced non-small-cell lung cancer (NSCLC) during first-line pembrolizumab plus chemotherapy, to provide imaging markers for overall survival (OS).

METHODS

The study included 133 patients treated with first-line pembrolizumab plus platinum-doublet chemotherapy. Serial CT scans during therapy were assessed for tumor burden dynamics during therapy, which were studied for the association with OS.

RESULTS

There were 67 responders, with overall response rate of 50%. The tumor burden change at the best overall response ranged from - 100.0% to + 132.1% (median of - 30%). Higher response rates were associated with younger age (p < 0.001) and higher programmed cell death-1 (PD-L1) expression levels (p = 0.01). Eighty-three patients (62%) showed tumor burden below the baseline burden throughout therapy. Using an 8-week landmark analysis, OS was longer in patients with tumor burden below the baseline burden in the first 8 weeks than in those who experienced ≥ 0% increase (median OS: 26.8 vs. 7.6 months, hazard ratio (HR): 0.36, p < 0.001). Tumor burden remained below their baseline throughout therapy was associated with significantly reduced hazards of death (HR: 0.72, p = 0.03) in the extended Cox models, after adjusting for other clinical variables. Pseudoprogression was noted in only one patient (0.8%).

CONCLUSIONS

Tumor burden staying below the baseline burden throughout the therapy was predictive of prolonged overall survival in patients with advanced NSCLC treated with first-line pembrolizumab plus chemotherapy, and may be used as a practical marker for therapeutic decisions in this widely used combination regimen.

CLINICAL RELEVANCE STATEMENT

The analysis of tumor burden dynamics on serial CT scans in reference to the baseline burden can provide an additional objective guide for treatment decision making in patients treated with first-line pembrolizumab plus chemotherapy for their advanced NSCLC.

KEY POINTS

• Tumor burden remaining below baseline burden during therapy predicted longer survival during first-line pembrolizumab plus chemotherapy. • Pseudoprogression was noted in 0.8%, demonstrating the rarity of the phenomenon. • Tumor burden dynamics may serve as an objective marker for treatment benefit to guide treatment decisions during first-line pembrolizumab plus chemotherapy.

Society for Immunotherapy of Cancer (SITC) clinical practice guideline on immunotherapy for the treatment of melanoma, version 3.0

Since the first approval for immune checkpoint inhibitors (ICIs) for the treatment of cutaneous melanoma more than a decade ago, immunotherapy has completely transformed the treatment landscape of this chemotherapy-resistant disease. Combination regimens including ICIs directed against programmed cell death protein 1 (PD-1) with anti-cytotoxic T lymphocyte antigen-4 (CTLA-4) agents or, more recently, anti-lymphocyte-activation gene 3 (LAG-3) agents, have gained regulatory approvals for the treatment of metastatic cutaneous melanoma, with long-term follow-up data suggesting the possibility of cure for some patients with advanced disease. In the resectable setting, adjuvant ICIs prolong recurrence-free survival, and neoadjuvant strategies are an active area of investigation. Other immunotherapy strategies, such as oncolytic virotherapy for injectable cutaneous melanoma and bispecific T-cell engager therapy for HLA-A*02:01 genotype-positive uveal melanoma, are also available to patients. Despite the remarkable efficacy of these regimens for many patients with cutaneous melanoma, traditional immunotherapy biomarkers (ie, programmed death-ligand 1 expression, tumor mutational burden, T-cell infiltrate and/or microsatellite stability) have failed to reliably predict response. Furthermore, ICIs are associated with unique toxicity profiles, particularly for the highly active combination of anti-PD-1 plus anti-CTLA-4 agents. The Society for Immunotherapy of Cancer (SITC) convened a panel of experts to develop this clinical practice guideline on immunotherapy for the treatment of melanoma, including rare subtypes of the disease (eg, uveal, mucosal), with the goal of improving patient care by providing guidance to the oncology community. Drawing from published data and clinical experience, the Expert Panel developed evidence- and consensus-based recommendations for healthcare professionals using immunotherapy to treat melanoma, with topics including therapy selection in the advanced and perioperative settings, intratumoral immunotherapy, when to use immunotherapy for patients with BRAFV600-mutated disease, management of patients with brain metastases, evaluation of treatment response, special patient populations, patient education, quality of life, and survivorship, among others.

Pseudo-Progression of Melanoma Treated with Nivolumab/Ipilimumab: A Case Report

BACKGROUND Melanoma is an aggressive skin cancer that can be difficult to manage. Its treatment has been transformed by immunotherapy. Melanoma cells frequently have mutations that make them vulnerable to attack by the immune system, and this is how immunotherapy can fight this cancer. Immunotherapy with checkpoint inhibitors targets mechanisms that malignant cells use to evade immune system detection, blocking proteins produced by the tumor, and allowing the immune system to identify and attack cancerous cells. CASE REPORT A 74-year-old woman presented with a lump on the right side of her chest. Tests revealed a metastatic malignant tumor with melanocytic differentiation. Stage IV melanoma was diagnosed, and the patient started therapy with nivolumab/ipilimumab for palliative intent, which she tolerated without adverse effects. However, she was hospitalized for Clostridioides difficile colitis after 3 treatment cycles, and computed tomography (CT) scan findings suggested disease progression. Positron emission tomography (PET)-CT obtained after her discharge from the hospital showed a complete metabolic response at all disease sites, indicating the initial progression was most likely a pseudo-progression from the use of immunotherapy. The patient continued with nivolumab as a single agent and has been doing well. CONCLUSIONS This case highlights the importance of careful evaluation of immunotherapy response in patients with melanoma. The initial progression noted in this patient was most likely pseudo-progression, which resolved with further immunotherapy. Clinicians should consider PET-CT imaging in cases of suspected pseudo-progression to avoid unnecessary changes in therapy. Patient response to immunotherapy demonstrates the effectiveness of immunotherapy in treating advanced melanoma.

Immune checkpoint inhibitors in hepatocellular carcinoma: emerging challenges in clinical practice

Systemic therapy for advanced hepatocellular carcinoma has expanded at an unprecedented pace over the past 5 years. After tyrosine kinase inhibitors dominated the field for more than a decade, immune checkpoint inhibitor (ICI)-based therapies have become the main component in systemic first-line treatment of this cancer. Delivery of immunotherapy in routine clinical practice recognises several challenges. In this Viewpoint, we discuss the major gaps in knowledge around the role of ICI-based therapies in patients with Child-Pugh class B. We discuss the challenges in individuals with rare histological subtypes of primary liver cancer, including combined hepatocellular-cholangiocarcinoma, fibrolamellar hepatocellular carcinoma, and sarcomatoid hepatocellular carcinoma. We also review data on ICI rechallenge in patients previously treated with ICIs, and discuss atypical patterns of progression related to immunotherapy (ie, hyperprogressive disease and pseudoprogression).

Dissociated response to PD-1 inhibitors combined with radiotherapy in patients with advanced metastatic solid tumors: a single-center experience

BACKGROUND

Anti-programmed death 1/anti-programmed death ligand 1 (PD-1/PD-L1) combined with radiotherapy (RT) has a synergistic effect on systemic tumor control. A dissociated response (DR), characterized by some lesions shrinking and others growing, has been recognized with immune checkpoint inhibitor (ICI) monotherapy or combination therapy. The objective of this study was to assess the frequency and clinical benefit of DR in patients with advanced metastatic solid tumors receiving PD-1 inhibitors in combination with RT.

METHODS

We conducted a single-center retrospective analysis of patients with advanced metastatic solid tumors receiving PD-1 inhibitor combined with RT at the Department of Radiotherapy & Oncology, The Second People's Hospital Affiliated with Soochow University. Treatment response was assessed for each measurable lesion according to the Response Evaluation Criteria in Solid Tumours ( RECIST) v 1.1 guidelines. Patterns of response are divided into four groups: (1) DR, (2) uniform response, (3) uniform progression, and (4) only stable lesions. The overall survival (OS) of different groups was compared using Kaplan-Meier methods and log-rank tests.

RESULTS

Between March 2019 and July 2022, 93 patients were included. The median follow-up was 10.5 months (95% CI 8.8-12.1). The most common tumor types were lung cancer (19.8%), colorectal adenocarcinoma (17.2%), and esophageal cancer (10.8%). DR was observed in 22 (23.7%) patients. The uniform progression and DR are two different patterns of progression. After confirming progression, the overall survival of patients with DR was significantly longer than that of patients with uniform progression (9.9 months (95%CI 5.7-14.1) vs. 4.2 months (95%CI 1.9-6.5), P = 0.028). Compared with DR patients who did not continue PD-1 inhibitor combined with RT or PD-1 inhibitor monotherapy (n = 12), DR patients who continued treatment (n = 10) had significantly longer OS (15.7 (95%CI 3.5-27.9) vs 8.2 (95%CI 5.6-10.8) months, P = 0.035).

CONCLUSIONS

DR is not uncommon (23.7%) in patients with advanced metastatic solid tumors treated with PD-1 inhibitors combined with RT and shows a relatively favorable prognosis. Some patients with DR may benefit from continued PD-1 inhibitor therapy in combination with RT or PD-1 inhibitor monotherapy and may have longer OS.

The benefit of treatment beyond progression with immune checkpoint inhibitors: a multi-center retrospective cohort study

OBJECTIVE

Treatment beyond progression (TBP) with immune checkpoint inhibitors (ICIs) is an evolving field due to the limitations of conventional imaging in response evaluation. However, real-life data on the benefit of TBP is scarce, especially from the limited resource settings and patients treated in the later lines. Therefore, we aimed to investigate the survival benefit of TBP with ICIs in patients with advanced tumors from a limited resource setting.

METHODS

For this multi-center retrospective cohort study, we included 282 patients treated with ICIs and had radiological progression according to RECIST 1.1 criteria. We evaluated post-progression survival according to the use of TBP (TBP and non-TBP groups) with univariate and multivariate analyses.

RESULTS

The cohort's median age was 61, and 84.4% were treated in the second or later lines. 82 (29.1%) of 282 patients continued on ICIs following the initial progression. In multivariate analyses, patients in the TBP group had improved post-progression survival compared to non-TBP (13.18 vs. 4.63 months, HR: 0.500, 95% CI: 0.349-0.717, p < 0.001). The benefit of the TBP was independent of the tumor type, treatment line, and age. Furthermore, TBP with ICIs remained associated with improved post-progression survival (HR: 0.600, 95% CI: 0.380-0.947, p = 0.028) after excluding the patients with no further treatment after progression in the non-TBP arm.

CONCLUSIONS

In this study, we observed that patients receiving ICIs beyond progression had considerably longer survival. Continuation of ICIs after progression should be considered a reasonable management option for patients with advanced cancer, specifically for patients with limited alternative options.

Patterns of pseudoprogression across different cancer entities treated with immune checkpoint inhibitors

BACKGROUND

Pseudoprogression (PsPD) is a rare response pattern to immune checkpoint inhibitor (ICI) therapy in oncology. This study aims to reveal imaging features of PsPD, and their association to other relevant findings.

METHODS

Patients with PsPD who had at least three consecutive cross-sectional imaging studies at our comprehensive cancer center were retrospectively analyzed. Treatment response was assessed according to immune Response Evaluation Criteria in Solid Tumors (iRECIST). PsPD was defined as the occurrence of immune unconfirmed progressive disease (iUPD) without follow-up confirmation. Target lesions (TL), non-target lesions (NTL), new lesions (NL) were analyzed over time. Tumor markers and immune-related adverse events (irAE) were correlated.

RESULTS

Thirty-two patients were included (mean age: 66.7 ± 13.6 years, 21.9% female) with mean baseline STL of 69.7 mm ± 55.6 mm. PsPD was observed in twenty-six patients (81.3%) at FU1, and no cases occurred after FU4. Patients with iUPD exhibited the following: TL increase in twelve patients, (37.5%), NTL increase in seven patients (21.9%), NL appearance in six patients (18.8%), and combinations thereof in four patients (12.5%). The mean and maximum increase for first iUPD in sum of TL was 19.8 and 96.8 mm (+ 700.8%). The mean and maximum decrease in sum of TL between iUPD and consecutive follow-up was - 19.1 mm and - 114.8 mm (-60.9%) respectively. The mean and maximum sum of new TL at first iUPD timepoint were 7.6 and 82.0 mm respectively. In two patients (10.5%), tumor-specific serologic markers were elevated at first iUPD, while the rest were stable or decreased among the other PsPD cases (89.5%). In fourteen patients (43.8%), irAE were observed.

CONCLUSIONS

PsPD occurred most frequently at FU1 after initiation of ICI treatment. The two most prevalent reasons for PsPD were TL und NTL progression, with an increase in TL diameter commonly below + 100%. In few cases, PsPD was observed even if tumor markers were rising compared to baseline. Our findings also suggest a correlation between PsPD and irAE. These findings may guide decision-making of ICI continuation in suspected PsPD.

Tumor therapeutic response monitored by telemetric temperature sensing, a preclinical study on immunotherapy and chemotherapy

Temperature in the body and the tumor reflects physiological and pathological conditions. A reliable, contactless, and simplistic measurement system can be used for long-term monitoring of disease progression and therapy response. In this study, miniaturized battery-free wireless chips implanted into growing tumors on small animals were used to capture both basal and tumor temperature dynamics. Three preclinical models: melanoma (B16), breast cancer (4T1), and colon cancer (MC-38), were treated with adoptive T cell transfer, AC-T chemotherapy, and anti-PD-1 immunotherapy respectively. Each model presents a distinctive pattern of temperature history dependent on the tumor characteristic and influenced by the administered therapy. Certain features are associated with positive therapeutic response, for instance the transient reduction of body and tumor temperature following adaptive T cell transfer, the elevation of tumor temperature following chemotherapy, and a steady decline of body temperature following anti-PD-1 therapy. Tracking in vivo thermal activity by cost-effective telemetric sensing has the potential of offering earlier treatment assessment to patients without requiring complex imaging or lab testing. Multi-parametric on-demand monitoring of tumor microenvironment by permanent implants and its integration into health information systems could further advance cancer management and reduce patient burden.

Image-based response assessment during immunotherapy in skin cancer

Immune-checkpoint inhibitors and further immunotherapeutic treatment strategies have significantly extended therapy options for melanoma and other skin cancer entities over the last decade. In the context of a broader application of immunotherapeutic approaches, sufficient ways to monitor the course of the disease during therapy are required. Immunotherapies are based on different ways of modulating the immune system. This leads to complex clinical response patterns including pseudoprogression and others, requiring an adaptation of conventional diagnostic imaging tools or the introduction of novel technologies. In this review, current non-invasive imaging approaches for response assessment during immunotherapies in skin cancers as well as their limitations are discussed. To overcome present hurdles, promising alternatives to better address novel imaging features during immunotherapy are depicted giving an outlook on what can be expected in the future.

Emerging and Evolving Concepts in Cancer Immunotherapy Imaging

Criteria based on measurements of lesion diameter at CT have guided treatment with historical therapies due to the strong association between tumor size and survival. Clinical experience with immune checkpoint modulators shows that editing immune system function can be effective in various solid tumors. Equally, novel immune-related phenomena accompany this novel therapeutic paradigm. These effects of immunotherapy challenge the association of tumor size with response or progression and include risks and adverse events that present new demands for imaging to guide treatment decisions. Emerging and evolving approaches to immunotherapy highlight further key issues for imaging evaluation, such as dissociated response following local administration of immune checkpoint modulators, pseudoprogression due to immune infiltration in the tumor environment, and premature death due to hyperprogression. Research that may offer tools for radiologists to meet these challenges is reviewed. Different modalities are discussed, including immuno-PET, as well as new applications of CT, MRI, and fluorodeoxyglucose PET, such as radiomics and imaging of hematopoietic tissues or anthropometric characteristics. Multilevel integration of imaging and other biomarkers may improve clinical guidance for immunotherapies and provide theranostic opportunities.

Immune-related dissociated response as a specific atypical response pattern in solid tumors with immune checkpoint blockade

Immune checkpoint blockade using immune checkpoint inhibitors, including cytotoxic T-lymphocyte-associated antigen–4 and programmed cell death protein-1/programmed cell death ligand–1 inhibitors, has revolutionized systematic treatment for advanced solid tumors, with unprecedented survival benefit and tolerable toxicity. Nivolumab, pembrolizumab, cemiplimab, avelumab, durvalumab, atezolizumab, and ipilimumab are currently approved standard treatment options for various human cancer types. The response rate to immune checkpoint inhibitors, however, is unsatisfactory, and unexpectedly, atypical radiological responses, including delayed responses, pseudoprogression, hyperprogression, and dissociated responses (DRs), are observed in a small subgroup of patients. The benefit of immunotherapy for advanced patients who exhibit atypical responses is underestimated according to the conventional response evaluation criteria in solid tumors (RECIST). In particular, DR is considered a mixed radiological or heterogeneous response pattern when responding and nonresponding lesions or new lesions coexist simultaneously. The rate of DR reported in different studies encompass a wide range of 3.3–47.8% based on diverse definition of DR. Although DR is also associated with treatment efficacy and a favorable prognosis, it is different from pseudoprogression, which has concordant progressive lesions and can be regularly captured by immune RECIST. This review article aims to comprehensively determine the frequency, definition, radiological evaluation, probable molecular mechanisms, prognosis, and clinical management of immune-related DR and help clinicians and radiologists objectively and correctly interpret this specific atypical response and better understand and manage cancer patients with immunotherapy and guarantee their best clinical benefit.

Improved Survival Prediction by Combining Radiological Imaging and S-100B Levels Into a Multivariate Model in Metastatic Melanoma Patients Treated With Immune Checkpoint Inhibition

Purpose

We explored imaging and blood bio-markers for survival prediction in a cohort of patients with metastatic melanoma treated with immune checkpoint inhibition.

Materials and Methods

94 consecutive metastatic melanoma patients treated with immune checkpoint inhibition were included into this study. PET/CT imaging was available at baseline (Tp0), 3 months (Tp1) and 6 months (Tp2) after start of immunotherapy. Radiological response at Tp2 was evaluated using iRECIST. Total tumor burden (TB) at each time-point was measured and relative change of TB compared to baseline was calculated. LDH, CRP and S-100B were also analyzed. Cox proportional hazards model and logistic regression were used for survival analysis.

Results

iRECIST at Tp2 was significantly associated with overall survival (OS) with C-index=0.68. TB at baseline was not associated with OS, whereas TB at Tp1 and Tp2 provided similar predictive power with C-index of 0.67 and 0.71, respectively. Appearance of new metastatic lesions during follow-up was an independent prognostic factor (C-index=0.73). Elevated LDH and S-100B ratios at Tp2 were significantly associated with worse OS: C-index=0.73 for LDH and 0.73 for S-100B. Correlation of LDH with TB was weak (r=0.34). A multivariate model including TB change, S-100B, and appearance of new lesions showed the best predictive performance with C-index=0.83.

Conclusion

Our analysis shows only a weak correlation between LDH and TB. Additionally, baseline TB was not a prognostic factor in our cohort. A multivariate model combining early blood and imaging biomarkers achieved the best predictive power with regard to survival, outperforming iRECIST.

Early Tumor Size Reduction of at least 10% at the First Follow-Up Computed Tomography Can Predict Survival in the Setting of Advanced Melanoma and Immunotherapy

RATIONALE AND OBJECTIVES

Early tumor size reduction (TSR) has been explored as a prognostic factor for survival in patients with advanced melanoma in clinical trials. The purpose of this analysis is to validate, in a routine clinical milieu, the predictive capacity of TSR by 10% for overall survival (OS) and progression-free survival (PFS) and to compare its predictive performance with the RECIST 1.1 criteria.

MATERIALS AND METHODS

This retrospective study was approved by the local ethics committee. A total of 152 patients with both CT before immunotherapy initiation and at first response evaluation after immunotherapy initiation were included. Prior to statistical analysis, treatment response was trichotomized as follows: Complete response and/or partial response, stable disease and progressive disease. Furthermore, response was dichotomized regarding TSR (TSR ≥ 10% and TSR < 10%). Kaplan-Meier survival estimates, Cox regression and Harrel's concordance index (C-index) were computed for prediction of overall survival and progression-free survival.

RESULTS

Tumor size reduction by at least 10% significantly differentiated between patients with increased survival from the ones with decreased survival (median OS: TSR ≥ 10%: 2137 days vs. TSR < 10%: 263 days) (p < 0.001) (median PFS: TSR ≥ 10%: 590 days vs.  TSR < 10%: 11 days) (p < 0.001). RECIST 1.1. criteria had a slightly higher C-index for overall survival reflecting a slight superior predictive capacity (RECIST: 0.69 vs TSR: 0.64) but a similar predictive capacity regarding progression-free survival (both: 0. 63).

CONCLUSION

Early tumor size reduction serves as a simple-to-use metric which can be implemented on the first follow-up CT. Tumor size reduction by at least 10% can be considered an additional biomarker predictive of overall survival and progression-free survival in routine clinical care and not only in the context of clinical trials in patients with advanced melanoma undergoing immunotherapy. Nevertheless, RECIST-based criteria should remain the main tool of treatment response assessment until results of prospective studies validating the TSR method are available.

Urinary detection of early responses to checkpoint blockade and of resistance to it via protease-cleaved antibody-conjugated sensors

Immune checkpoint blockade (ICB) therapy does not benefit the majority of treated patients, and those who respond to the therapy can become resistant to it. Here we report the design and performance of systemically administered protease activity sensors conjugated to anti-programmed cell death protein 1 (αPD1) antibodies for the monitoring of antitumour responses to ICB therapy. The sensors consist of a library of mass-barcoded protease substrates that, when cleaved by tumour proteases and immune proteases, are released into urine, where they can be detected by mass spectrometry. By using syngeneic mouse models of colorectal cancer, we show that random forest classifiers trained on mass spectrometry signatures from a library of αPD1-conjugated mass-barcoded activity sensors for differentially expressed tumour proteases and immune proteases can be used to detect early antitumour responses and discriminate resistance to ICB therapy driven by loss-of-function mutations in either the B2m or Jak1 genes. Biomarkers of protease activity may facilitate the assessment of early responses to ICB therapy and the classification of refractory tumours based on resistance mechanisms.

Natural killer cell-targeted immunotherapy for cancer

Natural killer (NK) cells were initially described in the early 1970s as major histocompatibility complex unrestricted killers due to their ability to spontaneously kill certain tumor cells. In the past decade, the field of NK cell-based treatment has been accelerating exponentially, holding a dominant position in cancer immunotherapy innovation. Generally, research on NK cell-mediated antitumor therapies can be categorized into three areas: choosing the optimal source of allogenic NK cells to yield massively amplified "off-the-shelf" products, improving NK cell cytotoxicity and longevity, and engineering NK cells with the ability of tumor-specific recognition. In this review, we focused on NK cell manufacturing techniques, some auxiliary methods to enhance the therapeutic efficacy of NK cells, chimeric antigen receptor NK cells, and monoclonal antibodies targeting inhibitory receptors, which can significantly augment the antitumor activity of NK cells. Notably, emerging evidence suggests that NK cells are a promising constituent of multipronged therapeutic strategies, strengthening immune responses to cancer.

Real-world effectiveness of nivolumab in advanced gastric cancer: the DELIVER trial (JACCRO GC-08)

BACKGROUND

There is no large real-world data regarding efficacy and safety of immunotherapy in gastric cancer (GC). Although some tumors can grow rapidly after immunotherapy, the patient proportions and survival outcomes are unclear in GC.

METHODS

A multicenter, prospective observational study was performed to evaluate clinical outcomes including survival time, safety, and tumor behavior of nivolumab treatment for patients with advanced GC. Primary endpoint was overall survival (OS), and secondary endpoints included response rate (RR), disease control rate (DCR), progression-free survival (PFS), tumor growth rate (TGR) at first evaluation, and safety.

RESULTS

Of 501 enrolled patients, 487 were evaluable (median age 70 years, 71% male, performance status 0/1/2 [42%/44%/14%], 21% HER2-pos, 42% patients with ascites). Median OS was 5.82 months (95% CI 5.29-7.00) with a 1-year survival rate of 30% and median PFS of 1.84 months (95% CI 1.71-1.97). The DCR was 39.4% and the RR was 14.2% (95% CI 10.3-18.8) in 282 patients with measurable lesions. In 219 patients evaluable for TGR, 20.5% were identified as hyperprogressive disease (HPD). OS from the first evaluation of patients with HPD was shorter compared with non-HPD (HR 1.77, 95% CI 1.25-2.51, P = 0.001), but it was not worse than that of patients with progression and non-HPD (HR 1.05, 95% CI 0.72-1.53, P = 0.8). A multivariate analysis revealed the presence of peritoneal metastasis was a prognostic factor for OS and PFS.

CONCLUSIONS

Our real-world data demonstrated the comparable survival time to a previous clinical trial and revealed the frequency and prognosis of patients with HPD in advanced GC treated with nivolumab.

A Machine learning model trained on dual-energy CT radiomics significantly improves immunotherapy response prediction for patients with stage IV melanoma

BACKGROUND

To assess the additive value of dual-energy CT (DECT) over single-energy CT (SECT) to radiomics-based response prediction in patients with metastatic melanoma preceding immunotherapy.

MATERIAL AND METHODS

A total of 140 consecutive patients with melanoma (58 female, 63±16 years) for whom baseline DECT tumor load assessment revealed stage IV and who were subsequently treated with immunotherapy were included. Best response was determined using the clinical reports (81 responders: 27 complete response, 45 partial response, 9 stable disease). Individual lesion response was classified manually analogous to RECIST 1.1 through 1291 follow-up examinations on a total of 776 lesions (6.7±7.2 per patient). The patients were sorted chronologically into a study and a validation cohort (each n=70). The baseline DECT was examined using specialized tumor segmentation prototype software, and radiomic features were analyzed for response predictors. Significant features were selected using univariate statistics with Bonferroni correction and multiple logistic regression. The area under the receiver operating characteristic curve of the best subset was computed (AUROC). For each combination (SECT/DECT and patient response/lesion response), an individual random forest classifier with 10-fold internal cross-validation was trained on the study cohort and tested on the validation cohort to confirm the predictive performance.

RESULTS

We performed manual RECIST 1.1 response analysis on a total of 6533 lesions. Multivariate statistics selected significant features for patient response in SECT (min. brightness, R²=0.112, padj. ≤0.001) and DECT (textural coarseness, R²=0.121, padj. ≤0.001), as well as lesion response in SECT (mean absolute voxel intensity deviation, R²=0.115, padj. ≤0.001) and DECT (iodine uptake metrics, R²≥0.12, padj. ≤0.001). Applying the machine learning models to the validation cohort confirmed the additive predictive power of DECT (patient response AUROC SECT=0.5, DECT=0.75; lesion response AUROC SECT=0.61, DECT=0.85; p<0.001).

CONCLUSION

The new method of DECT-specific radiomic analysis provides a significant additive value over SECT radiomics approaches for response prediction in patients with metastatic melanoma preceding immunotherapy, especially on a lesion-based level. As mixed tumor response is not uncommon in metastatic melanoma, this lends a powerful tool for clinical decision-making and may potentially be an essential step toward individualized medicine.

Tumor response as defined by iRECIST in gastrointestinal malignancies treated with PD-1 and PD-L1 inhibitors and correlation with survival

BACKGROUND

Atypical tumor response patterns during immune checkpoint inhibitor therapy pose a challenge to clinicians and investigators in immuno-oncology practice. This study evaluated tumor burden dynamics to identify imaging biomarkers for treatment response and overall survival (OS) in advanced gastrointestinal malignancies treated with PD-1/PD-L1 inhibitors.

METHODS

This retrospective study enrolled a total of 198 target lesions in 75 patients with advanced gastrointestinal malignancies treated with PD-1/PD-L1 inhibitors between January 2017 and March 2021. Tumor diameter changes as defined by immunotherapy Response Evaluation Criteria in Solid Tumors (iRECIST) were studied to determine treatment response and association with OS.

RESULTS

Based on the best overall response, the tumor diameter ranged from - 100 to + 135.3% (median: - 9.6%). The overall response rate was 32.0% (24/75), and the rate of durable disease control for at least 6 months was 30.7% (23/75, one (iCR, immune complete response) or 20 iPR (immune partial response), or 2iSD (immune stable disease). Using univariate analysis, patients with a tumor diameter maintaining a < 20% increase (48/75, 64.0%) from baseline had longer OS than those with ≥20% increase (27/75, 36.0%) and, a reduced risk of death (median OS: 80 months vs. 48 months, HR = 0.22, P = 0.034). The differences in age (HR = 1.09, P = 0.01), combined surgery (HR = 0.15, P = 0.01) and cancer type (HR = 0.23, P = 0.001) were significant. In multivariable analysis, patients with a tumor diameter with a < 20% increase had notably reduced hazards of death (HR = 0.15, P = 0.01) after adjusting for age, combined surgery, KRAS status, cancer type, mismatch repair (MMR) status, treatment course and cancer differentiation. Two patients (2.7%) showed pseudoprogression.

CONCLUSIONS

Tumor diameter with a < 20% increase from baseline during therapy in gastrointestinal malignancies was associated with therapeutic benefit and longer OS and may serve as a practical imaging marker for treatment response, clinical outcome and treatment decision making.

Imaging evaluation of lung cancer treated with PD-1/PD-L1 inhibitors

Immunotherapy (PD-1/PD-L1 inhibitors) has attracted attention for lung cancer treatment and recasted the administration of immunotherapeutics to patients who have advanced/metastatic diseases. Whether in combination or as monotherapy, these medications have become common therapies for certain patients with lung cancer. Moreover, their usage is expected to expand widely in the future. This review aims to discuss the imaging evaluation of lung cancer response to PD-1/PD-L1 therapy with focus on new radiological criteria for immunotherapy response. Abnormal radiological responses (pseudoprogression, dissociative responses, and hyperprogression) and immune-related adverse events are also described.

Multiparametric MRI of early tumor response to immune checkpoint blockade in metastatic melanoma

BACKGROUND

Immune checkpoint inhibitors are now standard of care treatment for many cancers. Treatment failure in metastatic melanoma is often due to tumor heterogeneity, which is not easily captured by conventional CT or tumor biopsy. The aim of this prospective study was to investigate early microstructural and functional changes within melanoma metastases following immune checkpoint blockade using multiparametric MRI.

METHODS

Fifteen treatment-naïve metastatic melanoma patients (total 27 measurable target lesions) were imaged at baseline and following 3 and 12 weeks of treatment on immune checkpoint inhibitors using: T2-weighted imaging, diffusion kurtosis imaging, and dynamic contrast-enhanced MRI. Treatment timepoint changes in tumor cellularity, vascularity, and heterogeneity within individual metastases were evaluated and correlated to the clinical outcome in each patient based on Response Evaluation Criteria in Solid Tumors V.1.1 at 1 year.

RESULTS

Differential tumor growth kinetics in response to immune checkpoint blockade were measured in individual metastases within the same patient, demonstrating significant intertumoral heterogeneity in some patients. Early detection of tumor cell death or cell loss measured by a significant increase in the apparent diffusivity (Dapp) (p<0.05) was observed in both responding and pseudoprogressive lesions after 3 weeks of treatment. Tumor heterogeneity, as measured by apparent diffusional kurtosis (Kapp), was consistently higher in the pseudoprogressive and true progressive lesions, compared with the responding lesions throughout the first 12 weeks of treatment. These preceded tumor regression and significant tumor vascularity changes (Ktrans, ve, and vp) detected after 12 weeks of immunotherapy (p<0.05).

CONCLUSIONS

Multiparametric MRI demonstrated potential for early detection of successful response to immune checkpoint inhibitors in metastatic melanoma.

The incidence of pseudoprogressive disease associated with programmed cell death 1/programmed cell death ligand 1 inhibitors: A meta-analysis

BACKGROUND

The method to evaluate the efficacy of programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) inhibitors has become a big concern for researchers with its widely application. Pseudoprogressive disease (PPD) makes this process more difficult, which means that the tumor progressed at the initial evaluation, but re-evaluation after continued treatment suggested that the treatment was effective. However, PPD has not attracted enough attention of clinical doctors. This article is to systematically evaluate the incidence of PPD associated with PD-1/PD-L1 inhibitors with meta-analysis, to provide guidance for the recognition and management of PPD.

METHODS

The databases of PubMed, EMBase, Cochrane Library were retrieved from the earliest collection date of the databases until Dec 5, 2019. The search terms of "pseudoprogressive disease, anti-PD-1, anti-PD-L1, PD-1/PD-L1 inhibitor, etc" were used for logistic combination search. Published studies on PPD caused by PD-1/PD-L1 inhibitors were included. Meta-analysis was performed with Stata 15.1. Subgroup analysis was performed according to the study population, tumor type, and evaluation criteria for efficacy.

RESULTS

Seven researches, including 1458 patients were taken into the study. Meta-analysis showed that the overall incidence of PPD was 3.70% (95% confidence interval [CI]: 2.70%, 4.90%). Subgroup analysis showed that the incidence of PPD was 3.30% (95% CI: 1.90%, 5.90%) in non-small cell lung cancer patients and 5.10% (95% CI: 2.30%, 11.6%) in melanoma patients. There was no statistically significant difference between East and West populations and among various efficacy evaluation criteria.

CONCLUSION

The incidence of PPD related to PD-1/PD-L1 inhibitors is not high, but the evaluation criteria has not yet been unified. Close monitoring, careful identification and proper application should be carried out in the clinic, and full management of the treatment with PD-1/PD-L1 inhibitors should be well done.

Monitoring CD8a+ T Cell Responses to Radiotherapy and CTLA-4 Blockade Using [64Cu]NOTA-CD8a PET Imaging

Purpose

Current response assessment systems for cancer patients receiving immunotherapy are limited. This is due to the associated inflammatory response that may confound the conventional morphological response evaluation criteria in solid tumors and metabolic positron emission tomography (PET) response criteria in solid. Recently, novel PET imaging techniques using radiolabeled antibodies and fragments have emerged as a particularly sensitive and specific modality for quantitative tracking of immune cell dynamics. Therefore, we sought to investigate the utility of Cu-64 labeled F(ab)′2 fragments for in vivo detection of CD8a⁺ T cells as a prognostic imaging biomarker of response to immunotherapy in an immunocompetent mouse model of colorectal cancer.

Procedures

[⁶⁴Cu]NOTA-CD8a was produced by enzymatic digestion of rat-anti-mouse CD8a antibody (clone YTS169.4), purified yielding isolated CD8a-F(ab)′2 fragments and randomly conjugated with the 2-S-(isothiocyanatbenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (p-SCN-Bn-NOTA) chelator. NOTA-CD8a was radiolabeled with Cu-64 and injected into CT26 tumor-bearing mice for longitudinal assessment. To investigate the value of [⁶⁴Cu]NOTA-CD8a PET imaging for assessment of treatment response, CT26 tumor-bearing mice were subjected to external radiation therapy (XRT) in combination with anti-CTLA-4 therapy. Imaging data was supported by flow cytometry and immunohistochemistry (IHC).

Results

Combination treatment with XRT and anti-CTLA-4 effectively inhibited tumor growth until day 22 post-therapy initiation (p = 0.0025) and increased the overall survival of mice compared to control (p = 0.0017). The [⁶⁴Cu]NOTA-CD8a tumor-to-heart ratio was increased in XRT + anti-CTLA-4-treated mice on day 8 after initiation of therapy (p = 0.0246). Flow cytometry and IHC confirmed the increase in tumor-infiltrating CD8a⁺ cells in XRT + anti-CTLA-4-treated mice. Furthermore, [⁶⁴Cu]NOTA-CD8a PET imaging distinguished responders and non-responders prior to treatment-induced changes in tumor volume among mice.

Conclusion

In the present study, we demonstrated that [⁶⁴Cu]NOTA-CD8a was able to detect treatment-induced changes in CD8a⁺ infiltration in murine CT26 colon tumors following a common preclinical combination treatment protocol. Overall, [⁶⁴Cu]NOTA-CD8a exhibited good prognostic and predictive value. We suggest that [⁶⁴Cu]NOTA-CD8a PET imaging can be used as an early biomarker of response to therapy in preclinical models.

Imaging Assessment of Tumor Response in the Era of Immunotherapy

Assessment of tumor response during treatment is one of the most important purposes of imaging. Before the appearance of immunotherapy, response evaluation criteria in solid tumors (RECIST) and positron emission tomography response criteria in solid tumors (PERCIST) were, respectively, the established morphologic and metabolic response criteria, and cessation of treatment was recommended when progressive disease was detected according to these criteria. However, various types of immunotherapy have been developed over the past 20 years, which show novel false positive findings on images, as well as distinct response patterns from conventional therapies. Antitumor immune response itself causes 18F-fluorodeoxyglucose (FDG) uptake in tumor sites, known as "flare phenomenon", so that positron emission tomography using FDG can no longer accurately identify remaining tumors. Furthermore, tumors often initially increase, followed by stability or decrease resulting from immunotherapy, which is called "pseudoprogression", so that progressive disease cannot be confirmed by computed tomography or magnetic resonance imaging at a single time point. As a result, neither RECIST nor PERCIST can accurately predict the response to immunotherapy, and therefore several new response criteria fixed for immunotherapy have been proposed. However, these criteria are still controversial, and also require months for response confirmation. The establishment of optimal response criteria and the development of new imaging technologies other than FDG are therefore urgently needed. In this review, we summarize the false positive images and the revision of response criteria for each immunotherapy, in order to avoid discontinuation of a truly effective immunotherapy.

Interim [18F]FDG PET/CT can predict response to anti-PD-1 treatment in metastatic melanoma

PURPOSE

In an attempt to identify biomarkers that can reliably predict long-term outcomes to immunotherapy in metastatic melanoma, we investigated the prognostic role of [18F]FDG PET/CT, performed at baseline and early during the course of anti-PD-1 treatment.

METHODS

Twenty-five patients with stage IV melanoma, scheduled for treatment with PD-1 inhibitors, were enrolled in the study (pembrolizumab, n = 8 patients; nivolumab, n = 4 patients; nivolumab/ipilimumab, 13 patients). [18F]FDG PET/CT was performed before the start of treatment (baseline PET/CT) and after the initial two cycles of PD-1 blockade administration (interim PET/CT). Seventeen patients underwent also a third PET/CT scan after administration of four cycles of treatment. Evaluation of patients' response by means of PET/CT was performed after application of the European Organization for Research and Treatment of Cancer (EORTC) 1999 criteria and the PET Response Evaluation Criteria for IMmunoTherapy (PERCIMT). Response to treatment was classified into 4 categories: complete metabolic response (CMR), partial metabolic response (PMR), stable metabolic disease (SMD), and progressive metabolic disease (PMD). Patients were further grouped into two groups: those demonstrating metabolic benefit (MB), including patients with SMD, PMR, and CMR, and those demonstrating no MB (no-MB), including patients with PMD. Moreover, patterns of [18F]FDG uptake suggestive of radiologic immune-related adverse events (irAEs) were documented. Progression-free survival (PFS) was measured from the date of interim PET/CT until disease progression or death from any cause.

RESULTS

Median follow-up from interim PET/CT was 24.2 months (19.3-41.7 months). According to the EORTC criteria, 14 patients showed MB (1 CMR, 6 PMR, and 7 SMD), while 11 patients showed no-MB (PMD). Respectively, the application of the PERCIMT criteria revealed that 19 patients had MB (1 CMR, 6 PMR, and 12 SMD), and 6 of them had no-MB (PMD). With regard to PFS, no significant difference was observed between patients with MB and no-MB on interim PET/CT according to the EORTC criteria (p = 0.088). In contrary, according to the PERCIMT criteria, patients demonstrating MB had a significantly longer PFS than those showing no-MB (p = 0.045). The emergence of radiologic irAEs (n = 11 patients) was not associated with a significant survival benefit. Regarding the sub-cohort undergoing also a third PET/CT, 14/17 patients (82%) showed concordant responses and 3/17 (18%) had a mismatch of response assessment between interim and late PET/CT.

CONCLUSION

PET/CT-based response of metastatic melanoma to PD-1 blockade after application of the recently proposed PERCIMT criteria is significantly correlated with PFS. This highlights the potential ability of [18F]FDG PET/CT for early stratification of response to anti-PD-1 agents, a finding with possible significant clinical and financial implications. Further studies including larger numbers of patients are necessary to validate these results.

Immunotherapy-Related Imaging Findings in Patients with Gynecological Malignancies: What Radiologists Need to Know

Immunotherapy is an effective treatment option for gynecological malignancies. Radiologists dealing with gynecological patients undergoing treatment with immune checkpoint inhibitors should be aware of unconventional immune-related imaging features for the evaluation of tumor response and immune-related adverse events. In this paper, immune checkpoint inhibitors used for gynecological malignancies and their mechanisms of action are briefly presented. In the second part, patterns of pseudoprogression are illustrated, and different forms of immune-related adverse events are discussed.

Higher CD4/CD8 ratio of pleural effusion predicts better survival for lung cancer patients receiving immune checkpoint inhibitors

Pleural effusion is a rare immune-related adverse event for lung cancer patients receiving immune checkpoint inhibitors (ICIs). We enrolled 281 lung cancer patients treated with ICIs and 17 were analyzed. We categorized the formation of pleural effusion into 3 patterns: type 1, rapid and massive; type 2, slow and indolent; and type 3, with disease progression. CD4/CD8 ratio of 1.93 was selected as the cutoff threshold to predict survival. Most patients of types 1 and 2 effusions possessed pleural effusion with CD4/CD8 ratios ≥ 1.93. The median OS time in type 1, 2, and 3 patients were not reached, 24.8, and 2.6 months, respectively. The median PFS time in type 1, 2, and 3 patients were 35.5, 30.2, and 1.4 months, respectively. The median OS for the group with pleural effusion CD4/CD8 ≥ 1.93 and < 1.93 were not reached and 2.6 months. The median PFS of those with pleural effusion CD4/CD8 ≥ 1.93 and < 1.93 were 18.4 and 1.2 months. In conclusion, patients with type 1 and 2 effusion patterns had better survival than those with type 3. Type 1 might be interpreted as pseudoprogression of malignant pleural effusion. CD4/CD8 ratio ≥ 1.93 in pleural effusion is a good predicting factor for PFS.

Pseudoprogression and Hyperprogression as New Forms of Response to Immunotherapy

Indications of immunotherapy in oncology are continuously expanding, and unconventional types of response have been observed with these new treatments. These include transient progressive disease followed by a partial response, described as pseudoprogression, that raises the question of treatment beyond progression; and rapid disease progression associated with clinical decline, reported as hyperprogression. However, there are currently no consensual definitions of these phenomena and their impact on daily practice remains unclear. We reviewed existing data on pseudoprogression and hyperprogression with a focus on the definitions, incidence, predictive factors, potential biological mechanisms, and methods published to help distinguish pseudoprogression from progression and hyperprogression. The incidence of pseudoprogression ranged from 0 to 15%, with some authors also including disease stabilization after a first progression. For hyperprogression, incidence ranged from 4 to 29% with various definitions, and several authors reported a correlation with worse survival. Both phenomena were observed in a large panel of cancer types. Several radiological and biological methods have been reported to help distinguish pseudoprogression from progression and hyperprogression, such as analysis of radiomics, and circulating-tumor DNA or cell-free DNA, but these need to be confirmed in larger prospective cohorts. In conclusion, pseudoprogression and hyperprogression are both frequent types of responses under immunotherapy, and there is a need to better characterize these to improve the management of cancer patients. Treatment beyond progression should always be considered with caution and necessitates close clinical monitoring. In case of suspected hyperprogression, immunotherapy should be stopped early.

Single-cell Analysis Technologies for Immuno-oncology Research: from Mechanistic Delineation to Biomarker Discovery

The successes with immune checkpoint blockade (ICB) and chimeric antigen receptor (CAR)-T-cell therapy in treating multiple cancer types have established immunotherapy as a powerful curative option for patients with advanced cancers. Unfortunately, many patients do not derive benefit or long-term responses, highlighting a pressing need to perform complete investigation of the underlying mechanisms and the immunotherapy-induced tumor regression or rejection. In recent years, a large number of single-cell technologies have leveraged advances in characterizing immune system, profiling tumor microenvironment, and identifying cellular heterogeneity, which establish the foundations for lifting the veil on the comprehensive crosstalk between cancer and immune system during immunotherapies. In this review, we introduce the applications of the most widely used single-cell technologies in furthering our understanding of immunotherapies in terms of underlying mechanisms and their association with therapeutic outcomes. We also discuss how single-cell analyses help to deliver new insights into biomarker discovery to predict patient response rate, monitor acquired resistance, and support prophylactic strategy development for toxicity management. Finally, we provide an overview of applying cutting-edge single-cell spatial-omics to point out the heterogeneity of tumor-immune interactions at higher level that can ultimately guide to the rational design of next-generation immunotherapies.

A mechanistic systems pharmacology modeling platform to investigate the effect of PD-L1 expression heterogeneity and dynamics on the efficacy of PD-1 and PD-L1 blocking antibodies in cancer

Tumors have developed multitude of ways to evade immune response and suppress cytotoxic T cells. Programed cell death protein 1 (PD-1) and programed cell death ligand 1 (PD-L1) are immune checkpoints that when activated, rapidly inactivate the cytolytic activity of T cells. Expression heterogeneity of PD-L1 and the surface receptor dynamics of both PD-1 and PD-L1 may be important parameters in modulating the immune response. PD-L1 is expressed on both tumor and non-tumor immune cells and this differential expression reflects different aspects of anti-tumor immunity. Here, we developed a mechanistic computational model to investigate the role of PD-1 and PD-L1 dynamics in modulating the efficacy of PD-1 and PD-L1 blocking antibodies. Our model incorporates immunological synapse restricted interaction of PD-1 and PD-L1, basal parameters for receptor dynamics, and T cell interaction with tumor and non-tumor immune cells. Simulations predict the existence of a threshold in PD-1 expression above which there is no efficacy for both anti-PD-1 and anti-PD-L1. Model also predicts that anti-tumor response is more sensitive to PD-L1 expression on non-tumor immune cells than tumor cells. New combination strategies are suggested that may enhance efficacy in resistant cases such as combining anti-PD-1 with a low dose of anti-PD-L1 or with inhibitors of PD-L1 recycling and synthesis. Another combination strategy suggested by the model is the combination of anti-PD-1 and anti-PD-L1 with enhancers of PD-L1 degradation rate. Virtual patients are then generated to test specific biomarkers of response. Intriguing predictions that emerge from the virtual patient simulations are that PD-1 blocking antibody results in higher response rate than PD-L1 blockade and that PD-L1 expression density on non-tumor immune cells rather than tumor cells is a predictor of response.

Tumor Response Dynamics During First-Line Pembrolizumab Therapy in Patients With Advanced Non-Small-Cell Lung Cancer

The objectives of the study were to characterize the tumor burden dynamics on serial computed tomography scans in patients with advanced non-small-cell lung cancer treated with first-line pembrolizumab and to identify imaging markers for prolonged overall survival (OS).

MATERIALS AND METHODS

Eighty-eight patients treated with first-line pembrolizumab monotherapy were evaluated on serial computed tomography scans to characterize their quantitative tumor burden during therapy. Tumor burden dynamics were studied for the association with OS.

RESULTS

The overall response rate was 42% (37/88), with the median tumor burden changes at the best overall response of -18.3% (range, -100.0% to +103.6%). Response rates were higher in men than in women (P = .05) and in patients with higher programmed cell death ligand-1 expression levels (P = .02). Tumor burden stayed below the baseline burden throughout therapy in 55 patients (63%). In an 8-week landmark analysis, patients with tumor burden below the baseline burden during the first 8 weeks of therapy had longer OS compared with patients who had ≥ 0% increase (median OS, 30.7 v 16.2 months; hazard ratio [HR] = 0.44; P = .01). In the extended Cox models, patients whose tumor burden stayed below the baseline burden throughout therapy had significantly reduced hazards of death (HR = 0.41, P = .003, univariate; HR = 0.35, P = .02, multivariate). Only one patient (1.1%) experienced pseudoprogression with initial tumor increase and subsequent tumor regression.

CONCLUSION

In patients with advanced non-small-cell lung cancer treated with first-line single-agent pembrolizumab, tumor burden reduction below the baseline burden during therapy was an independent marker for prolonged OS, which may serve as a practical guide for treatment decisions.

Integrative Genomic Analyses of Patient-Matched Intracranial and Extracranial Metastases Reveal a Novel Brain-Specific Landscape of Genetic Variants in Driver Genes of Malignant Melanoma

BACKGROUND

Development of brain metastases in advanced melanoma patients is a frequent event that limits patients' quality of life and survival. Despite recent insights into melanoma genetics, systematic analyses of genetic alterations in melanoma brain metastasis formation are lacking. Moreover, whether brain metastases harbor distinct genetic alterations beyond those observed at different anatomic sites of the same patient remains unknown.

EXPERIMENTAL DESIGN AND RESULTS

In our study, 54 intracranial and 18 corresponding extracranial melanoma metastases were analyzed for mutations using targeted next generation sequencing of 29 recurrently mutated driver genes in melanoma. In 11 of 16 paired samples, we detected nucleotide modifications in brain metastases that were absent in matched metastases at extracranial sites. Moreover, we identified novel genetic variants in ARID1A, ARID2, SMARCA4 and BAP1, genes that have not been linked to brain metastases before; albeit most frequent mutations were found in ARID1A, ARID2 and BRAF. Conclusion: Our data provide new insights into the genetic landscape of intracranial melanoma metastases supporting a branched evolution model of metastasis formation.

Imaging challenges of immunotherapy and targeted therapy in patients with brain metastases: response, progression, and pseudoprogression

The advent of immunotherapy using immune checkpoint inhibitors (ICIs) and targeted therapy (TT) has dramatically improved the prognosis of various cancer types. However, following ICI therapy or TT-either alone (especially ICI) or in combination with radiotherapy-imaging findings on anatomical contrast-enhanced MRI can be unpredictable and highly variable, and are often difficult to interpret regarding treatment response and outcome. This review aims at summarizing the imaging challenges related to TT and ICI monotherapy as well as combined with radiotherapy in patients with brain metastases, and to give an overview on advanced imaging techniques which potentially overcome some of these imaging challenges. Currently, major evidence suggests that imaging parameters especially derived from amino acid PET, perfusion-/diffusion-weighted MRI, or MR spectroscopy may provide valuable additional information for the differentiation of treatment-induced changes from brain metastases recurrence and the evaluation of treatment response.

Immune Checkpoint Inhibitor with or without Radiotherapy in Melanoma Patients with Brain Metastases: A Systematic Review and Meta-Analysis

Objective

Immune checkpoint inhibitor (ICI) therapy has shown activity against melanoma brain metastases. Recently, promising results have also been reported for ICI combination therapy and ICI combined with radiotherapy. We aimed to evaluate radiologic response and adverse event rates of these therapeutic options by a systematic review and meta-analysis.

Materials and Methods

A systematic literature search of Ovid-MEDLINE and EMBASE was performed up to October 12, 2019 and included studies evaluating the intracranial objective response rates (ORRs) and/or disease control rates (DCRs) of ICI with or without radiotherapy for treating melanoma brain metastases. We also evaluated safety-associated outcomes.

Results

Eleven studies with 14 cohorts (3 with ICI combination therapy; 5 with ICI combined with radiotherapy; 6 with ICI monotherapy) were included. ICI combination therapy {pooled ORR, 53% (95% confidence interval [CI], 44–61%); DCR, 57% (95% CI, 49–66%)} and ICI combined with radiotherapy (pooled ORR, 42% [95% CI, 31–54%]; DCR, 85% [95% CI, 63–95%]) showed higher local efficacy compared to ICI monotherapy (pooled ORR, 15% [95% CI, 11–20%]; DCR, 26% [95% CI, 21–32%]). The grade 3 or 4 adverse event rate was significantly higher with ICI combination therapy (60%; 95% CI, 52–67%) compared to ICI monotherapy (11%; 95% CI, 8–17%) and ICI combined with radiotherapy (4%; 95% CI, 1–19%). Grade 3 or 4 central nervous system (CNS)-related adverse event rates were not different (9% in ICI combination therapy; 8% in ICI combined with radiotherapy; 5% in ICI monotherapy).

Conclusion

ICI combination therapy or ICI combined with radiotherapy showed better local efficacy than ICI monotherapy for treating melanoma brain metastasis. The grade 3 or 4 adverse event rate was highest with ICI combination therapy, and the CNS-related grade 3 or 4 event rate was similar. Prospective trials will be necessary to compare the efficacy of ICI combination therapy and ICI combined with radiotherapy.

Comparison of Radiological Tumor Response Based on iRECIST and RECIST 1.1 in Metastatic Clear-Cell Renal Cell Carcinoma Patients Treated with Programmed Cell Death-1 Inhibitor Therapy

Objective

To evaluate the radiological tumor response patterns and compare the response assessments based on immune-based therapeutics Response Evaluation Criteria in Solid Tumors (iRECIST) and RECIST 1.1 in metastatic clear-cell renal cell carcinoma (mccRCC) patients treated with programmed cell death-1 (PD-1) inhibitors.

Materials and Methods

All mccRCC patients treated with PD-1 inhibitors at Henan Cancer Hospital, China, between January 2018 and April 2019, were retrospectively studied. A total of 30 mccRCC patients (20 males and 10 females; mean age, 55.6 years; age range, 37–79 years) were analyzed. The target lesions were quantified on consecutive CT scans during therapy using iRECIST and RECIST 1.1. The tumor growth rate was calculated before and after therapy initiation. The response patterns were analyzed, and the differences in tumor response assessments of the two criteria were compared. The intra- and inter-observer variabilities of iRECIST and RECIST 1.1 were also analyzed.

Results

The objective response rate throughout therapy was 50% (95% confidence interval [CI]: 32.1–67.9) based on iRECIST and 30% (95% CI: 13.6–46.4) based on RECIST 1.1. The time-to-progression (TTP) based on iRECIST was longer than that based on RECIST 1.1 (median TTP: not reached vs. 170 days, p = 0.04). iRECIST and RECIST 1.1 were discordant in 8 cases, which were evaluated as immune-unconfirmed PD based on iRECIST and PD based on RECIST 1.1. Six patients (20%, 6/30) had pseudoprogression based on iRECIST, of which four demonstrated early pseudoprogression and two had delayed pseudoprogression. Significant differences in the tumor response assessments based on the two criteria were observed (p < 0.001). No patients demonstrated hyperprogression during the study period.

Conclusion

Our study confirmed that the iRECIST criteria are more capable of capturing immune-related atypical responses during immunotherapy, whereas conventional RECIST 1.1 may underestimate the benefit of PD-1 inhibitors. Pseudoprogression is not rare in mccRCC patients during PD-1 inhibitor therapy, and it may last for more than the recommended maximum of 8 weeks, indicating a limitation of the current strategy for immune response monitoring.

Clinical Pharmacology and Interplay of Immune Checkpoint Agents: A Yin-Yang Balance

T cells have a central role in immune system balance. When activated, they may lead to autoimmune diseases. When too anergic, they contribute to infection spread and cancer proliferation. Immune checkpoint proteins regulate T cell function, including cytotoxic T lymphocyte antigen-4 (CTLA-4) and programmed cell death-1 (PD-1) and its ligand (PD-L1). These nodes of self-tolerance may be exploited pharmacologically to downregulate (CTLA-4 agonists) and activate [CTLA-4 and PD-1/PD-L1 antagonists, also called immune checkpoint inhibitors (ICIs)] the immune system.CTLA-4 agonists are used to treat rheumatologic immune disorders and graft rejection. CTLA-4, PD-1, and PD-L1 antagonists are approved for multiple cancer types and are being investigated for chronic viral infections. Notably, ICIs may be associated with immune-related adverse events (irAEs), which can be highly morbid or fatal. CTLA-4 agonism has been a promising method to reverse such life-threatening irAEs. Herein, we review the clinical pharmacology of these immune checkpoint agents with a focus on their interplay in human diseases.

Incidence of Pseudoprogression during Immune Checkpoint Inhibitor Therapy for Solid Tumors: A Systematic Review and Meta-Analysis

BackgroundImmune checkpoint inhibitors (ICIs) have been increasingly used in cancer treatment, and a subset of patients undergo pseudoprogression. Recognizing the incidence of pseudoprogression is critical for clinical practice.PurposeTo evaluate by systematic review and meta-analysis the incidence of pseudoprogression in cancer treatment with ICIs, and compare the incidence according to response criteria, tumor types, and immunotherapeutic agents.Materials and MethodsMedline and Embase were searched to identify relevant studies published before December 31, 2018. Clinical trials, post hoc analysis of clinical trials, and prospective studies on ICI treatment in patients with malignant solid tumors were included. Pooled incidence of pseudoprogression for all included studies, per definition of pseudoprogression, cancer type, and drug type, was obtained by random-effects models with inverse variance weighting model.ResultsSeventeen studies with 3402 patients were analyzed. The pooled incidence of pseudoprogression was 6.0% (95% confidence interval: 5.0%, 7.0%). The definition of pseudoprogression were divided into four categories: progressive disease followed by partial response (PR) or complete response (CR) but not stable disease (SD) with Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 (six studies); progressive disease followed by SD or PR or CR with RECIST 1.1 (five studies); progressive disease followed by SD or PR or CR with RECIST 1.0 (three studies); and progressive disease followed by SD or PR or CR with immune-related response criteria (irRC) (three studies). Incidence of pseudoprogression varied from 4.5% to 8.0% per definition, ranged from 5.0% to 7.0% per cancer type, and was 5.6% with the monotherapy of programmed cell death-1 inhibitor.ConclusionThe overall incidence of pseudoprogression was 6.0% and was less than 10% in subgroup analyses according to the definitions of pseudoprogression, cancer type, and immune checkpoint inhibitor type. Varying definitions across trials and studies indicates the need for uniform criteria of pseudoprogression for solid tumors.© RSNA, 2020Online supplemental material is available for this article.See also the article by Dodd and MacDermott in this issue.

Monitoring von Immuntherapien

Hintergrund

Immuntherapien spielen in der Behandlung fortgeschrittener onkologischer Erkrankungen eine zunehmende Rolle. Bei einigen Patienten birgt die radiologische Diagnostik durch atypische, immuntherapieinduziete Therapieverläufe neue Herausforderungen.

Ziel der Arbeit

Dieser Beitrag soll einen Überblick über die bildgebenden Methoden des Monitorings von Immuntherapien geben, die assoziierten Phänomene Pseudoprogress und Hyperprogress erörtern sowie die Evaluationskriterien iRECIST vorstellen, welche sich als Evaluationsstandard für klinische Studien anbieten. Zusätzlich werden die radiologisch wichtigsten Nebenwirkungen und ihre bildmorphologischen Charakteristika beschrieben.

Material und Methoden

Für diesen Übersichtsartikel wurden Studienergebnisse und Reviews seit 2009 ausgewertet. Die Literaturrecherche erfolgte mittels PubMed, die Suchbegriffe enthielten „immunotherapy“, „checkpoint inhibitor“, „pseudoprogression“, „iRECIST“ und „immune related adverse events“.

Ergebnisse und Diskussion

Mit einer Inzidenz von bis zu 10 % ist der Pseudoprogress insgesamt selten; aktuell ist die Differenzierung von einem echten Progress nur durch eine Beobachtung des zeitlichen Verlaufs möglich. Die 2017 erschienenen iRECIST-Kriterien enthalten daher die neuen Kategorien unbestätigter (immune unconfirmed progressive disease iUPD) und bestätigter Progress (immune confirmed progressive disease iCPD). Bisher konnte keine evidenzbasierte Empfehlung bezüglich des Zeitintervalls zwischen den Untersuchungen gegeben werden. Als radiologisch wichtigste Nebenwirkungen sind die Hypophysitis und die Pneumonitis zu nennen. Letztere kann sich in verschiedenen Mustern der interstitiellen Pneumonie präsentieren. Die Differenzierung zwischen Pneumonitis, Infektion und Tumorprogress kann diagnostische Schwierigkeiten mit sich bringen.

Early Onset Immune-Related Adverse Event to Identify Pseudo-Progression in a Patient With Ovarian Cancer Treated With Nivolumab: A Case Report and Review of the Literature

Background: Immune checkpoint inhibitors (ICIs) have shown clinical benefit in many advanced tumors, however, pseudo-progression is a noted phenomenon of ICIs characterized by radiologic enlargement of the tumor burden, followed by regression. How to differentiate pseudo-progression from progression remains a critical clinical issue. Recent studies have demonstrated the association between immune-related adverse events (irAEs) and efficacy of ICIs. Here we demonstrated an ovarian cancer patient treated with nivolumab in whom the early-onset irAE was identified to differentiate pseudo-progression from progression.

Case presentation: Here we present the case of a 47-years-old woman with histopathologically confirmed diagnosis of metastatic ovarian cystadenocarcinoma. Immunohistochemical examination showed 10% of tumor cells to express the programmed cell death receptor ligand 1 (PD-L1) and a 381-gene panel sequencing in a College of American Pathologists (CAP) certificated lab revealed a moderate mutational tumor burden with 5.7 Mutants/Mb. The patient received nivolumab 100 mg every 2 weeks as a fourth line treatment. Within the first 2 months, the tumor volume increased by 23.6%. However, the patient experienced an elevation of Alanine aminotransferase (ALT) and Aspartate aminotransmerase (AST), which was diagnosed as the immune-related hepatitis. Thus, the treatment continued and afterwards, the patient reached a partial response (PR) to nivolumab and the progression-free survival was 9 months.

Conclusion: To our knowledge, this is the first case describing early-onset immune-related adverse events to identify pseudo-progression in a patient with ovarian cancer treated with nivolumab, and PD-L1 expression level may be a predictive biomarker in the immunotherapy of ovarian cancer.

Atypical patterns of response and progression in the era of immunotherapy combinations

In the immunoncology era, an acceleration of tumor growth upon immune checkpoint inhibitors (ICI), defined as hyperprogressive disease (HPD) has been observed across different cancers. Although in non-small-cell lung cancer, most of the available evidence regarding HPD has been reported for patients treated with single agent PD-1 and PD-L1 inhibitors, in retrospective series a variable proportion of patients receiving ICI combinations also experienced HPD. Similarly, the shape of survival curves and the progression rates in clinical trials testing combinations of PD-1/PD-L1 inhibitors and anti-CTLA-4 agents suggest the occurrence of HPD. Few data are available regarding pseudoprogression upon ICI combinations. However, considering that pseudoprogression has been reported for anti-PD-1/PD-L1 agents and for CTLA-4 inhibitors separately, it is likely that it may occur also upon combinations of these two classes of drugs.

Resistance mechanisms to immune checkpoints blockade by monoclonal antibody drugs in cancer immunotherapy: Focus on myeloma

Multiple myeloma (MM) is a clonal B-cell malignancy characterized by the accumulation of neoplastic proliferation of a plasma cell in the bone marrow that produces a monoclonal immunoglobulin. The immune checkpoint inhibitors against programmed death-1/programmed death-1 ligand and cytotoxic T-lymphocyte antigen 4 axis have demonstrated appropriate anticancer activity in several solid tumors and liquid cancers, and are rapidly transforming the practice of medical oncology. However, in a high percentage of patients, the efficacy of immune checkpoints blockade remains limited due to innate or primary resistance. Moreover, the malignancies progress in many patients due to acquired or secondary resistance, even after the clinical response to immune checkpoints' blockade. The evidence shows that multiple tumor-intrinsic and tumor-extrinsic factors and alterations in signaling pathways are involved in primary and secondary resistance to immune checkpoints blockade. Improved identification of intrinsic and extrinsic factors and mechanisms of resistance or response to immune checkpoints blockade may not only provide novel prognostic or predictive biomarkers but also guide the optimal combination/sequencing of immune checkpoint blockade therapy in the clinic. Here, we review the underlying biology and role of immune checkpoints blockade in patients with MM. Furthermore, we review the host and tumor-related factor effects on immune checkpoints blockade in MM immunotherapy.

Impact of pseudoprogression and treatment beyond progression on outcome in patients with non-small cell lung cancer treated with immune checkpoint inhibitors

Background

Immune checkpoint inhibitors (ICI) have become an important treatment option for non-small cell lung cancer (NSCLC). We aimed to evaluate the clinical impact of pseudoprogression (PsP) and treatment beyond RECIST1.1-defined progressive disease (TBP) on outcome in NSCLC patients treated with ICI.

Methods

NSCLC patients treated with ICI between Mar 2016 and July 2018 were recruited in a consecutive manner. Response was assessed every 8–12 weeks using RECIST1.1 and iRECIST. Based on iRECIST, PsP was defined as progressive disease (PD) on RECIST1.1 subsequently reset to non-PD categories. Using log-rank test, progression-free survival (PFS) was compared between patients with and without PsP, and overall survival (OS) was compared between patients treated with and without TBP. The impact of TBP on OS was evaluated through multivariate Cox proportional hazard models.

Results

Of the 189 patients, seven (3.7%) experienced PsP which mostly occurred approximately 3 months after baseline. The median PFS was significantly longer in patients with PsP (not reached) than those without PsP (3.8 months, P = .02). Among patients who demonstrated PD according to RECIST1.1, median OS was significantly longer in patients with TBP (17.2 months) than those without TBP (7.4 months, P < .001). On multivariate analysis adjusting other covariates, TBP (HR, 0.4; 95% CI, 0.2–0.7) remained as a significant protective factor for mortality.

Conclusion

PsP occurred in 3.7% of NSCLC patients under ICI treatment. Based on iRECIST scheme, PsP and TBP may be associated with survival benefit.

Overall survival benefit of continuing immune checkpoint inhibitors treatment post dissociated response in patients with advanced lung cancer

PURPOSE

Dissociated response (DR, reduction at baseline or increase < 20% in target lesions compared with nadir in the presence of new lesions) was observed in 20-34% of patients treated with immune checkpoint inhibitors (ICIs). DRs were defined as progression disease (PD) per response evaluation criteria in solid tumors (RECIST v1.1), while evaluation criteria related to immunotherapy incorporated the new lesions into the total tumor burden or conducted further evaluation after 4-8 weeks rather than declaring PD immediately. The main objective of this study is to compare survival between people who continuing initial ICIs treatment and those who switched to other anticancer therapy at the time of DR.

PATIENTS AND METHODS

235 patients with advanced lung cancer (LC) treated with ICIs were evaluated. Propensity score matching (PSM) was used to minimize potential confounding factors. Post-DR OS, target lesion changes were evaluated.

RESULTS

52 patients had been estimated as DRs. After PSM, the continuing ICIs treatment Post-DR cohort still had a significantly longer median post-DR OS than discontinuing ICIs treatment Post-DR cohort, 10.63 months (95% CI 6.27-NA) versus 4.33 months (95% CI 1.77-NA), respectively (p = 0.016).

CONCLUSION

Within the limitations of this single-center retrospective analysis, clinically stable patients who were judged by clinicians to be eligible for continuing ICIs treatment post-DR derived apparent OS benefit than discontinuing counterpart.