Pembrolizumab Monotherapy Research Articles

Abstract 1184: Combination pembrolizumab and radiotherapy induces anti-tumor immune responses in immunologically-cold non-small cell lung cancer

Abstract Introduction: Primary resistance to immune checkpoint inhibition (ICI) is in part driven by a “cold” tumor microenvironment in the context of low PD-L1 expression, low tumor mutation burden or oncogenic mutations that drive tumor immune exclusion. Radiation has the potential to sensitize tumors to ICI through extra-tumoral T cell activation in response to tumor antigens released from irradiated cancer cells (abscopal effect). Here, we investigate tumor microenvironment and T cell repertoire reshaping leveraging serial biospecimens from a phase 2 randomized clinical trial of stereotactic body radiation therapy followed by pembrolizumab (SBRT arm) vs. pembrolizumab alone (control arm) in non-small cell lung cancer (NSCLC; NCT02492568). Methods: We employed whole exome sequencing, RNA sequencing and T cell receptor (TCR) sequencing to analyze 293 serial tumor and peripheral blood samples collected at baseline and after 8 weeks of treatment from 72 patients in the control (n=35) and SBRT (n=37) arms. Immunologically-cold tumors were defined as low TMB (<300 mutations per exome, n=43), PD-L1 null (0% expression on immunohistochemistry, n=41), or WNT-activated (presence of mutations affecting genes in the WNT pathway, n=10). TCR clonotypic differential abundance analyses and RNA sequencing deconvolution and gene set enrichment analyses were performed on baseline and on-therapy blood and tumor samples from the control and SBRT arms. Results: Patients with immunologically-cold tumors in the SBRT arm had significantly longer progression free survival compared to the pembrolizumab monotherapy arm (log rank p=0.029 for TMB-low, p=0.022 for PD-L1-null, p=0.037 for the WNT-activated subsets). Induction of interferon-gamma, interferon-alpha, antigen processing and presentation, and inflammatory response gene sets was significantly enriched on-therapy in the SBRT arm (FDR adjusted p<0.01 for TMB-low, PD-L1-null, and WNT-activated tumors). We observed greater enrichment in newly expanded TCR clones on-therapy intratumorally and in peripheral blood in the SBRT arm compared to the control arm (mean 16.17 vs 7.54 clonotypes, p=0.022 in tumor; mean 4.56 vs 1.00, p=0.039 in blood; Mann-Whitney U test). Similarly, we noted greater expansion of pre-existing TCR clones in the SBRT arm than within the control arm (mean 34.83 vs 18.69, p=0.021 in tumor; mean 21.61 vs 8.15, p=0.009 in blood; Mann-Whitney U test). Within the SBRT arm, there was no significant difference in T cell expansion between TMB-stratified (<300 mutations vs >=300 mutations) or PD-L1-stratified (0% vs >= 1% expression) groups. Conclusions: SBRT followed by pembrolizumab was associated with priming and augmenting anti-tumor immune responses in immunologically-cold NSCLC, which opens a therapeutic window of opportunity for radiotherapy to overcome primary resistance to immune checkpoint inhibition. Citation Format: Justin Huang, Willemijn S. Theelen, Zineb Belcaid, Mimi Najjar, Christopher Cherry, Archana Balan, James R. White, Noushin Niknafs, Jaime Wehr, M.M. van den Heuvel, Rachel Karchin, Paul Baas, Victor E. Velculescu, Valsamo Anagnostou. Combination pembrolizumab and radiotherapy induces anti-tumor immune responses in immunologically-cold non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1184.

Abstract 4187: Transcriptome profiling and characterization of peritoneal metastasis ovarian cancer xenografts in humanized mice

Abstract Background: Although immunotherapy has not yet been as successful in ovarian cancer (OC), it remains a potential therapeutic strategy. Preclinical models of OC are necessary to evaluate the efficacy of immuno-oncology (IO) drugs targeting human cancer and immune components but have been underutilized. Developing mouse models with a humanized (Hu) immune system can help understand the human immune response to IO drugs, including immune checkpoint inhibitors (ICIs), which have demonstrated limited effectiveness in OC patients. Methods: We established OC xenograft Hu-mouse models by intraperitoneally injecting luciferase-expressing SKOV-3 Luc and OVCAR-3 Luc OC cells into CD34+ Hu-mice. Tumor growth was monitored through bioluminescence imaging (BLI). We assessed the efficacy of PD-1 blockade with pembrolizumab in the SKOV-3 Luc Hu-mouse model. The immune profiles of the tumors were characterized using colorimetric immunostaining and flow cytometry. Additionally, we analyzed RNA-seq data to investigate the gene expression signature of pembrolizumab refractory tumors. Results: We confirmed tumor development in both OC cell lines within CD34+ Hu-mice. In these models, human lymphocyte and myeloid cell subsets were present in the tumors, draining lymph nodes, blood, and spleens. The SKOV-3 Luc tumor-bearing Hu-mice did not respond to pembrolizumab monotherapy. These tumors exhibited a high presence of tumor-infiltrating macrophages. Tumors in Hu-mice unresponsive to pembrolizumab showed a lower abundance of CD8+ T-cells, memory B cells, plasma cells, and a higher proportion of naïve M0 macrophages and mast cells compared to the PBS control. Furthermore, we identified 43 significantly enriched gene sets in these tumors. The differentially expressed genes (DEGs) were predominantly enriched in HDAC class I, RB1, KLF1/3, TCF21, MYD88, SMARCE1 target genes, and genes associated with epithelial-mesenchymal transition (EMT) and fibroblasts. Conclusion: Our xenograft Hu-mouse model of OC provides a valuable tool for investigating the efficacy of IO drugs. The insights gained from this model offer potential avenues to explore mechanisms of resistance to PD-1/PD-L1 blockade in OC. Citation Format: Sung Wan Kang, Ji-young Lee, Ok-Ju Kang, Yong-Man Kim, Eun Kyung Choi, Shin-Wha Lee. Transcriptome profiling and characterization of peritoneal metastasis ovarian cancer xenografts in humanized mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4187.

Abstract 2519: Alteration of tumor immune microenvironment after recurrence and its impact on the efficacy of anti-PD-1 antibody in resected non-small cell lung cancer patients

Abstract Background: Tumor immune microenvironment (TIME), including programmed death-1 ligand-1 (PD-L1) and CD8-positive tumor-infiltrating lymphocytes (TIL), has been suggested as a potential biomarker to predict the efficacy of anti-PD-1 antibody. Postoperative recurrence in patients with non-small cell lung cancer (NSCLC) is treated with therapeutic strategies similar to those for metastatic disease. However, in postoperative recurrence cases, PD-L1 evaluation is generally based on archival resection specimens, because there is little opportunity for a new biopsy of the recurrent site. Therefore, it remains unclear whether TIME of recurrent lesion is similar to TIME of primary lesion at surgery, and the efficacy of anti-PD-1 antibody for postoperative recurrent NSCLC patients based on TIME status at surgery is unknown. Materials and Methods: Cohort A included 59 patients with advanced and 25 patients with postoperative recurrence NSCLC who treated with first-line pembrolizumab monotherapy. PD-L1 expression and CD8-TIL were evaluated immunohistochemically in tumor specimens obtained at diagnosis in the advanced cases and at surgery in the postoperative recurrence cases. Tumor proportion score for PD-L1 and the extent of CD8-TIL were evaluated and classified as high or low. TIME was categorized into 4 subclasses, according to the respective PD-L1 and CD8-TIL, as follows: (class I) high/high; (class II) low/low; (class III) high/low; and (class IV) low/high. Progression-free survival (PFS) of pembrolizumab was compared based on TIME. Cohort B consisted of 50 NSCLC patients who underwent radical resection, and whose tumor specimens were obtained from recurrent site. As in cohort A, TIME was assessed for paired resection and recurrent tumor samples. Results: In cohort A, the median PFS of pembrolizumab for the advanced cases were 25.7 months in class I (n=25), 2.3 months in class II (n=8), 8.0 months in class III (n=20), and 6.5 months in class IV (n=6) (p<0.001), respectively; while those for the postoperative recurrence cases were 9.0 months (n=7), 4.3 months (n=7), 7.6 months (n=6), and 2.5 months (n=5) (p=0.55), respectively. In cohort B, TIME for resected primary lesion were observed in 9 with class I, 20 with class II, 3 with class III and 18 patients with class IV, respectively. The concordance of PD-L1 category (high vs low) between resected primary lesion and recurrent lesion was 88.0%, while that of TIME classification was 54.0%. Conclusion: TIME classification using tumor specimens just before administration of anti-PD-1 antibody was useful predictive biomarker. However, TIME alterations between resection and postoperative recurrence were observed in many cases, suggesting that TIME based on tumor specimens at surgery may not be useful for predicting the efficacy of anti-PD-1 antibody for postoperative recurrent NSCLC. Citation Format: Yoshiya Matsumoto, Tetsuya Watanabe, Megumi Mizutani, Akira Sugimoto, Hiroaki Nagamine, Yoko Tani, Kenji Sawa, Takuma Tsukioka, Hiroyasu Kaneda, Shigeki Mitsuoka, Noritoshi Nishiyama, Tomoya Kawaguchi. Alteration of tumor immune microenvironment after recurrence and its impact on the efficacy of anti-PD-1 antibody in resected non-small cell lung cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2519.

Abstract 2911: Prevalence of potential antibody drug conjugate targets and co-expression with PD-L1 in breast cancer and lung cancer patients with clinical response information

Abstract Breast and non-small cell lung cancer (NSCLC) are two of the most important diseases for antibody drug conjugate (ADC) development. ADCs targeting HER2 and TROP2 are currently approved in select breast and lung subgroups with ADC’s to many other tumor targets currently in clinical development. Based on TCGA mRNA expression data, ADC tumor targets currently under investigation for treatment of solid tumors have variable overlap in breast and lung cancers, however little is known about the overlap of ADC targets with PD-L1 which is a predictive biomarker in TNBC and for pembrolizumab monotherapy. In the current study, the prevalence and co-expression of ADC targets (HER2, TROP2, Nectin-4, B7-H3, B7-H4, HER3, FOLR1) were investigated in the context of PD-L1 status and clinical response data for standard-of-care (SOC) and immunotherapy, in breast and NSCLC cancer subtypes. Tissue microarrays (TMAs) comprising treatment naïve tumor samples (1mm cores) and including TNBC (26 patients), ER+ BC (90 patients), and NSCLC (adeno & squamous subtypes; 146 patients), all with full clinical follow-up information, were examined by immunohistochemistry (IHC) in serial sections for each ADC target and PD-L1, applying widely used and well optimized IHC assays on the Ventana and Dako Link 48 platforms. Established scoring methods were employed for analysis of PD-L1 and HER2, except for the addition of an exploratory ultra-low score for HER2. All other ADC targets were scored by digital image analysis to deliver percentage positive tumor expression at high (3+), moderate (2+), weak (1+) and negative (0) intensities. Taken together, this analysis revealed variable prevalence for each target in breast and lung cancer histologies by subtype, including differing overlap between ADC targets within tumor indications. In addition, prevalence of each ADC target in breast cancer characterized by HR status and HER2 subgroups (HER2-positive, low, ultra-low, negative) indicated potential opportunities for ADC clinical development in these subgroups. Co-prevalence of the selected ADC targets with PD-L1 CPS>10 (predictive for Pembrolizumab response in TNBC) and PD-L1 CPS categories of interest for NSCLC revealed patterns of expression in support of combination therapies. Furthermore, expression and co-prevalence data for each ADC target +/- PD-L1 was characterized in association with response to immunotherapy or other SOC. In summary, these data provide better understanding of which breast and lung cancer subtypes express the selected ADC targets uniquely and competitively which may be key to future clinical and diagnostic development. Citation Format: Marie Cumberbatch, Woo Ho Kim, Milan Bhagat, John Cogswell. Prevalence of potential antibody drug conjugate targets and co-expression with PD-L1 in breast cancer and lung cancer patients with clinical response information [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2911.

Abstract 4969: Investigating digital pathology tumor microenvironment features for immunotherapy outcome in patients with advanced non-small cell lung cancer

Abstract Introduction The composition of the tumor microenvironment (TME) has been shown to influence response to immunotherapy (IO). In this study, we investigated digital pathology TME features of IO outcomes among patients with non-squamous, non-small cell lung cancer (NSCLC) within a real-world dataset. Methods From the nationwide de-identified Flatiron Health-Foundation Medicine NSCLC clinico-genomic database, a cohort of 50 EGFR/ALK-negative, non-squamous NSCLC patients treated with first-line pembrolizumab monotherapy (mono-IO) or pembrolizumab in combination with carboplatin/cisplatin and pemetrexed (chemo-IO) that had available whole slide images of H&E-stained tissue resection specimens were included. The de-identified data originated from approximately 280 US cancer clinics (~800 sites of care). AI-powered TME characterization models developed by PathAI (Boston, MA; commercially available as PathExplore™) were deployed on scanned H&E slides to extract a panel of cell- and tissue-level human interpretable features (HIFs). Cox proportional hazards regression was used to identify digital pathology features or HIFs associated with overall survival. Results 17 HIFs were associated with better survival and 19 HIFs were associated with worse survival among patients treated with mono-IO (p < 0.05). Lymphocyte features were among the HIFs associated with favorable survival, including density of lymphocyte cells in cancer epithelium (hazard ratio (HR) per unit standard deviation (SD) = 0.46 [0.24, 0.88], p-value = 0.02) and proportion of lymphocyte cells relative to total immune cells in cancer epithelium (HR per unit SD = 0.61 [0.39, 0.95], p-value = 0.03). Cell-level features associated with worse survival included density of fibroblast cells in stroma (HR per unit SD = 1.51 [1.01, 2.25], p-value = 0.05). These associations remained after adjusting for tumor mutational burden (TMB) (N = 29 low, 21 high) and PD-L1 status (N = 0 negative, 1 low-positive, 17 high-positive, 32 unknown). Additionally, similar associations were not observed among patients treated with chemo-IO. High lymphocyte density was associated with better survival compared to low lymphocyte density in mono-IO treated patients (adjusted HR per unit SD = 0.36 [0.18, 0.74], p-value = 0.01) but not in chemo-IO treated patients (adjusted HR per unit SD = 1.10 [0.76, 1.60], p-value = 0.6). Conclusion These results indicate that the composition of TME assessed via digital pathology may have utility in identifying NSCLC patients that will respond to first-line immune checkpoint inhibitors beyond the established IO biomarkers. Citation Format: Ericka M. Ebot, Kuei-Ting Chen, Mikayla Biggs, Douglas I. Lin, Julia A. Elvin, Garrett M. Frampton, James J. Pao. Investigating digital pathology tumor microenvironment features for immunotherapy outcome in patients with advanced non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4969.

Network meta-analysis of first-line systemic regimens for older patients with advanced NSCLC.

Various immunotherapy treatments have received approval for the treatment of advanced non-small cell lung cancer (NSCLC), either as standalone or in conjunction with chemotherapy, contingent upon the extent of PD-L1 expression. These treatments are commonly utilized in clinical practice. However, a specific gap exists in direct comparisons of these regimens in elderly patients. The aim of this network meta-analysis (NMA) was to examine the effectiveness of PD-1/PD-L1 inhibitors, either alone or in conjunction with chemotherapy, as the initial treatment for elderly patients diagnosed with advanced NSCLC. We extensively searched PubMed, EMBASE and the Cochrane Library to gather randomized clinical trials that utilized PD-1/PD-L1 inhibitors as the first-line therapy for advanced NSCLC. By means of Bayesian NMA, we conducted an analysis on hazard ratios (HRs) related to overall survival (OS). A total of 5240 patients were included in the 21 trials. Across all studies, cemiplimab exhibited a noteworthy superiority to chemotherapy in terms of OS [HR = 0.48, 95% confidence interval (CI): 0.3-0.77]. In the subgroup analysis, it was observed that patients with PD-L1 expression of 50% or higher experienced the greatest OS benefit from cemiplimab (HR = 0.48, 95% CI: 0.3-0.77). Conversely, the cohort with unselected PD-L1 scores (>1 or any score) exhibited the greatest OS benefit when treated with pembrolizumab combined with chemotherapy, as indicated by a HR of 0.69 (95% CI: 0.52-0.9). Chemotherapy combined with pembrolizumab and cemiplimab monotherapy may represent the reference regimens for older patients with NSCLC with unselected and >50% PD-L1 expression, respectively.

Efficacy Assessment of Post-nephrectomy Adjuvant Therapies in Patients with Renal Cell Carcinoma.

The objective of our study was to integrate the efficacy results of post-nephrectomy adjuvant therapies in renal cell carcinoma (RCC) patients with risk of recurrence, and attempt to determine the optimal intervention choice. We performed standard meta-analysis procedures in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The PubMed, Embase, and Cochrane Library databases were searched from inception to 22 September 2022. Randomized controlled trials reporting overall survival (OS) or disease-free survival (DFS) of adjuvant therapies, including immune checkpoint inhibitors (ICIs) and targeted therapies, in adult post-nephrectomy RCC patients were eligible for inclusion. Seven studies involving 7548 participants were included in our analyses. In contrast with placebo, DFS benefit with ICIs was only observed in female RCC patients and RCC patients with high programmed death-ligand 1 (PD-L1) expression (≥ 1%), sarcomatoid features, and M0 intermediate-high risk. Network meta-analyses demonstrated that pembrolizumab exhibited both DFS and OS benefit compared with placebo, sunitinib, sorafenib, and girentuximab, and only DFS benefit compared with atezolizumab and nivolumab plus ipilimumab. Our results suggest that post-nephrectomy RCC patients with sarcomatoid differentiation and high PD-L1 expression were more responsive to ICIs. Furthermore, pembrolizumab monotherapy exhibited superior DFS and OS results over other adjuvant therapies.

Frontline pembrolizumab monotherapy for metastatic non-small cell lung cancer with PD-L1 expression ≥50%: real-world outcomes in a US community oncology setting.

This study investigated real-world time on treatment (rwToT) and overall survival (OS) for patients with metastatic non-small cell lung cancer (mNSCLC) who initiated first-line (1L) pembrolizumab monotherapy. We also explored discontinuation reasons and subsequent treatments, stratified by number of cycles among those who completed ≥17 cycles of 1L pembrolizumab. Patients with mNSCLC without actionable genetic aberrations, Eastern Cooperative Oncology Group performance status (ECOG PS) 0-2 and unknown, and PD-L1 TPS ≥ 50% starting 1L pembrolizumab monotherapy between 24-Oct-2016 and 31-Dec-2018 within The US Oncology Network were identified retrospectively and evaluated using structured data, with a data cutoff of 30-Sep-2021. Patient characteristics and disposition were summarized using descriptive statistics. OS and rwToT were evaluated using Kaplan-Meier method for all ECOG PS and PS 0-1. A subgroup of patients who completed ≥17 cycles were evaluated using supplemental chart review data to discern reasons for discontinuation. Of the 505 patients with mNSCLC with PD-L1 TPS ≥50%, 61% had ECOG PS 0-1, 23% had ECOG PS 2, and 65% had nonsquamous histology. Median rwToT and OS of pembrolizumab were 7.0 (95% CI, 6.0-8.4) months and 24.5 (95% CI, 20.1-29.3) months, respectively. In the subgroup with ECOG PS 0-1, they were 7.6 months (95% CI, 6.2-9.2) and 28.8 months (95% CI, 22.4-37.5), respectively. Of the 103 patients who completed ≥17 cycles, 57 (55.3%) patients received 17 - 34 cycles and 46 (44.7%) patients received ≥35 cycles. Approximately 7.7% of the study population received pembrolizumab beyond 35 cycles. Most common reasons for discontinuation were disease progression (38.6%) and toxicity (19.3%) among patients who received 17-34 cycles of pembrolizumab, and disease progression (13.0%) and completion of therapy (10.9%) among patients who received ≥35 cycles. Consistent with findings from KEYNOTE-024 and other real-world studies, this study demonstrates the long-term effectiveness of pembrolizumab monotherapy as 1L treatment for mNSCLC with PD-L1 TPS ≥50%. Among patients who completed ≥17 cycles, nearly half completed ≥35 cycles. Disease progression and toxicity were the most common reasons for discontinuation among patients who received 17-34 cycles of pembrolizumab. Reasons for discontinuation beyond 35 cycles need further exploration.

79 Biomarker of response to immunotherapy

79 Biomarker of response to immunotherapy

The UK Divide: Does Having a Pembrolizumab–Chemotherapy Option in Head and Neck Cancer Matter? Real-world Experience of First-line Palliative Pembrolizumab Monotherapy and Pembrolizumab–Chemotherapy Combination in Scotland

AimsThe Scottish Medical Consortium recently approved first-line pembrolizumab monotherapy or in combination with chemotherapy for head and neck squamous cell carcinoma in the palliative setting, contrasting with the decision made by the National Institute for Health and Care Excellence, who approved monotherapy alone in England and Wales. The aim of this study was to provide real-world performance data for first-line pembrolizumab-containing treatments for head and neck squamous cell carcinoma in the palliative setting in Scotland. Materials and methodsWe analysed the electronic records of patients who started pembrolizumab-containing treatment between 1 March 2020 and 30 September 2021. Outcomes included overall survival, progression-free survival (PFS), the duration of response and the disease control rate. Data were compared with the KEYNOTE-048 study and clinical factors were evaluated for association with survival. ResultsOur cohort included 91 patients (median follow-up 10.8 months). Patient characteristics were similar to those in the KEYNOTE-048 study, although our cohort had a higher proportion of patients with newly diagnosed, non-metastatic disease. For patients receiving monotherapy (n = 76), 12- and 24-month overall survival were 45% and 27%, respectively. For patients receiving pembrolizumab–chemotherapy (n = 15), 12-month overall survival was 60% (24-month overall survival had not yet been reached). Experiencing one or more immune-related adverse event (irAE; versus no irAEs), of any grade, was associated with favourable overall survival and PFS for patients receiving monotherapy in both univariable Log-rank analysis (median overall survival 17.4 months versus 8.6 months, respectively, P = 0.0033; median PFS 10.9 months versus 3.0 months, respectively, P < 0.0001) and multivariable analysis (Cox proportional hazards regression: overall survival hazard ratio 0.31, P = 0.0009; PFS hazard ratio 0.17, P < 0.0001). ConclusionOur real-world data support the KEYNOTE-048 study findings and the value of combination treatment options. Additionally, our data show that irAEs of any grade, as reported in routine clinical records, are associated with better outcomes in this patient group, adding to the growing body of evidence showing that irAEs are generally a positive marker of programmed death-ligand 1 (PD-L1) inhibitor response.

A real-world experience of pembrolizumab monotherapy in microsatellite instability-high and/or tumor mutation burden-high metastatic castration-resistant prostate cancer: outcome analysis

A real-world experience of pembrolizumab monotherapy in microsatellite instability-high and/or tumor mutation burden-high metastatic castration-resistant prostate cancer: outcome analysis

Cancer testis antigen burden (CTAB): a novel biomarker of tumor-associated antigens in lung cancer

BackgroundCancer-testis antigens (CTAs) are tumor antigens that are normally expressed in the testes but are aberrantly expressed in several cancers. CTA overexpression drives the metastasis and progression of lung cancer, and is associated with poor prognosis. To improve lung cancer diagnosis, prognostic prediction, and drug discovery, robust CTA identification and quantitation is needed. In this study, we examined and quantified the co-expression of CTAs in lung cancer to derive cancer testis antigen burden (CTAB), a novel biomarker of immunotherapy response.MethodsFormalin fixed paraffin embedded (FFPE) tumor samples in discovery cohort (n = 5250) and immunotherapy and combination therapy treated non-small cell lung cancer (NSCLC) retrospective (n = 250) cohorts were tested by comprehensive genomic and immune profiling (CGIP), including tumor mutational burden (TMB) and the mRNA expression of 17 CTAs. PD-L1 expression was evaluated by IHC. CTA expression was summed to derive the CTAB score. The median CTAB score for the discovery cohort of 170 was applied to the retrospective cohort as cutoff for CTAB “high” and “low”. Biomarker and gene expression correlation was measured by Spearman correlation. Kaplan–Meier survival analyses were used to detect overall survival (OS) differences, and objective response rate (ORR) based on RECIST criteria was compared using Fisher’s exact test.ResultsThe CTAs were highly co-expressed (p < 0.05) in the discovery cohort. There was no correlation between CTAB and PD-L1 expression (R = 0.011, p = 0.45) but some correlation with TMB (R = 0.11, p = 9.2 × 10–14). Kaplan–Meier survival analysis of the immunotherapy-treated NSCLC cohort revealed better OS for the pembrolizumab monotherapy treated patients with high CTAB (p = 0.027). The combination group demonstrated improved OS compared to pembrolizumab monotherapy group (p = 0.04). The pembrolizumab monotherapy patients with high CTAB had a greater ORR than the combination therapy group (p = 0.02).ConclusionsCTA co-expression can be reliably measured using CGIP in solid tumors. As a biomarker, CTAB appears to be independent from PD-L1 expression, suggesting that CTAB represents aspects of tumor immunogenicity not measured by current standard of care testing. Improved OS and ORR for high CTAB NSCLC patients treated with pembrolizumab monotherapy suggests a unique underlying aspect of immune response to these tumor antigens that needs further investigation.

Tolerability and efficacy of the cancer vaccine UV1 in patients with recurrent or metastatic PD-L1 positive head and neck squamous cell carcinoma planned for first-line treatment with pembrolizumab - the randomized phase 2 FOCUS trial.

Globally, head and neck squamous cell carcinoma (HNSCC) is the seventh most common malignancy. Despite aggressive multimodal treatment approaches, recurrent and/or metastatic (R/M) disease develops in >50% of patients. In this setting, pembrolizumab was approved for patients with PD-L1 expression. However, response rates with checkpoint inhibitor monotherapy remain limited and strategies to strengthen tumor-directed immune responses are needed. The FOCUS trial is designed to estimate the effectiveness of UV1 vaccination in combination with pembrolizumab versus pembrolizumab as a single agent in patients with R/M HNSCC. The FOCUS trial is a two-armed, randomized, multicenter phase II study which was designed to evaluate the efficacy and feasibility of the hTERT-targeted cancer vaccine UV1 as add-on to pembrolizumab in the 1st line treatment of patients with R/M PD-L1 positive (combined positive score ≥1) HNSCC. Secondary objectives are the exploration of patient subgroups most likely deriving benefit from this novel combination and the establishment of liquid biopsy tumor monitoring in HNSCC. This clinical study was designed and will be conducted in compliance with Good Clinical Practice and in accordance with the Declaration of Helsinki. It is intended to publish the results of this study in peer-reviewed scientific journals and to present its content at academic conferences. A significant number of patients with R/M HNSCC are frail and may not tolerate chemotherapy, these patients may only be suitable for pembrolizumab monotherapy. However, long term disease stabilizations remain the exception and there is a need for the development of efficacious combination regimens for this patient population. The FOCUS study aims to optimize treatment of R/M HNSCC patients with this promising new treatment approach. https://clinicaltrials.gov/study/NCT05075122, identifier NCT05075122.

Phase 1 study of pembrolizumab plus chemotherapy in Japanese patients with extensive-stage small-cell lung cancer

SummaryBackgroundPart E of the KEYNOTE-011 (NCT01840579) study assessed the safety and antitumor activity of pembrolizumab plus platinum-etoposide chemotherapy in Japanese patients with previously untreated extensive-stage small-cell lung cancer (ES-SCLC).MethodsPatients received 4 cycles of pembrolizumab (200 mg) every 3 weeks in combination with cisplatin (75 mg/m2) and etoposide (100 mg/m2; days 1, 2, 3) in cohort 1; with carboplatin (AUC 5 mg/mL/min) and etoposide (100 mg/m2; days 1, 2, 3) in cohort 2; or with cisplatin/etoposide and pegfilgrastim (3.6 mg; cycle 1, day 4) in cohort 3. Combination therapy was followed by pembrolizumab monotherapy (31 cycles). The primary endpoint was safety and tolerability (including dose-limiting toxicities; DLTs).ResultsFifteen patients were included in the study (cohort 1, n = 6; cohort 2, n = 6; cohort 3, n = 3). Median time from treatment allocation to data cutoff was 22.1 months (range, 4.1‒32.4 months). DLTs occurred in 3 patients in cohort 1 (one patient with grade 4 laryngeal stenosis and grade 3 febrile neutropenia; two patients with grade 3 febrile neutropenia); no patients in cohorts 2 or 3 experienced DLTs. Grade ≥ 3 treatment-related adverse events included leukopenia (67%) and neutropenia (87%). Among all patients, ORR was 67% (95% CI, 38%‒88%) and median DOR was 4.5 months (range, 2.8‒28.8 months). Median PFS was 4.2 months (95% CI, 3.0‒7.8 months) and median OS was 22.1 months (95% CI, 7.4‒25.9 months).ConclusionPembrolizumab in combination with platinum-etoposide therapy had manageable toxicity with no new safety signals and was associated with antitumor activity in Japanese patients with ES-SCLC.Trial RegistrationClinicalTrials.gov, NCT01840579.

Phase 3 KEYNOTE-676 cohort A: Bacillus Calmette-Guérin (BCG) with or without pembrolizumab for high-risk (HR) non–muscle-invasive bladder cancer (NMIBC) that persists/recurs after BCG induction.

TPS722 Background: Intravesical instillation of BCG is a standard-of-care treatment for patients with HR NMIBC, but up to 50% of patients later experience disease recurrence or progression to muscle-invasive bladder cancer (MIBC) despite BCG treatment. In the phase 2 KEYNOTE-057 study (NCT02625961), pembrolizumab monotherapy was shown to have antitumor activity in patients with HR BCG–unresponsive NMIBC who had carcinoma in situ (CIS) with or without papillary tumors and in patients with only papillary tumors. In cohort A of the randomized, phase 3 KEYNOTE-676 trial (NCT03711032), pembrolizumab plus BCG versus BCG alone is being evaluated in patients with persistent/recurrent HR NMIBC after first BCG induction. Methods: Key eligibility criteria include adults with histologically confirmed HR NMIBC (T1, high-grade Ta, and/or CIS) that is persistent/recurrent following 1 adequate course of BCG induction therapy, have no concurrent extravesical disease or history of extravesical disease that recurred within 2 years, have an ECOG PS score of 0 to 2, and have undergone cystoscopy/TURBT ≤12 weeks before randomization. Approximately 430 patients will be randomly assigned 1:1 to receive pembrolizumab 200 mg intravenously every 3 weeks plus BCG or BCG alone. BCG (50 mg) will be administered by intravesical instillation as induction therapy once weekly for 6 weeks and then as maintenance therapy once weekly for 3 weeks at weeks 13 and 25, then every 24 weeks (Q24W) thereafter. Treatment will continue for approximately 2 years (pembrolizumab) or 3 years (BCG), or until confirmed persistent/recurrent HR NMIBC or disease progression to MIBC or metastatic bladder cancer, unacceptable toxicity, or withdrawal. Randomization to treatment will be stratified by PD-L1 combined positive score (≥10 or ˂10), histology (CIS or non-CIS), and NMIBC disease history (persistence/recurrence 0 to ≤6 months or recurrence ˃6 to ≤12 months or recurrence ˃12 to ≤24 months). Response will be assessed by local cystoscopy and blinded independent central review of urine cytology and biopsy (as applicable) every 12 weeks for years 1 to 2 and Q24W for years 3 to 5. Computed tomography urography will occur every 72 weeks through year 5, then every 104 weeks thereafter. The primary end point is complete response rate in patients with CIS. Secondary end points are duration of response in patients with CIS, event-free survival, recurrence-free survival, time to cystectomy, overall survival, disease-specific survival, safety and tolerability, and patient-reported outcomes. Enrollment incohort A of KEYNOTE-676 is ongoing in Asia, Australia, Europe, and North America. Clinical trial information: NCT03711032 .

Pembrolizumab with favezelimab or vibostolimab for patients with bacillus Calmette-Guérin (BCG)–unresponsive high-risk (HR) non–muscle-invasive bladder cancer (NMIBC): Phase 2 KEYNOTE-057 cohort C.

TPS719 Background: In cohort A of the phase 2 KEYNOTE-057 study (NCT02625961), the PD-1 inhibitor pembrolizumab demonstrated antitumor activity (3-month complete response rate, 41%) in patients with BCG-unresponsive HR NMIBC with carcinoma in situ (CIS) ± papillary tumors who are ineligible for or declined radical cystectomy (RC). However, treatment combinations that improve outcomes and durability of response with pembrolizumab monotherapy are needed. Coinhibitory receptors LAG-3 and TIGIT contribute to immune tolerance in the tumor microenvironment, and co-blockade of PD-1 with LAG-3 or TIGIT has demonstrated antitumor activity in clinical studies. In cohort C of KEYNOTE-057, efficacy and safety of coformulations of pembrolizumab and the LAG-3 inhibitor favezelimab or the TIGIT inhibitor vibostolimab are being evaluated in patients with BCG-unresponsive HR NMIBC with CIS ± papillary tumors. Methods: Key eligibility criteria include adults with histologically confirmed HR NMIBC (CIS ± high-grade Ta or T1 at baseline) that is BCG-unresponsive (persistent or recurrent CIS ± Ta/T1 ≤12 month of completing adequate BCG therapy) who are ineligible for or declined RC and have an ECOG PS of 0-2. Enrollment is planned for 60 patients. Patients will be randomly assigned 1:1 to receive the coformulation of pembrolizumab 200 mg and vibostolimab 200 mg or the coformulation of pembrolizumab 200 mg and favezelimab 800 mg intravenously every 3 weeks for ≤35 cycles or until central pathology–confirmed ≥T1 at any time point, persistent or recurrent CIS or high-grade Ta at 24-week efficacy review or thereafter, unacceptable toxicity, patient or physician decision to withdraw, or administrative reasons to discontinue. Tumor assessment will be performed every 12 weeks for 2 years and every 24 weeks thereafter for up to 5 years. Primary end point is 12-month complete response rate of HR NMIBC by cystoscopy, cytology, biopsy, and radiologic imaging by central pathology and radiology review. Secondary end points include duration of response of HR NMIBC; overall complete response rate and complete response rates at 3 and 6 months; progression-free survival (PFS) to worsening of grade, stage, or death; PFS to muscle-invasive or metastatic disease or death; and overall survival. Efficacy will be evaluated in patients who receive ≥1 dose of treatment and have a baseline evaluation consisting of pre-enrollment cystoscopy, TURBT/biopsy, urine cytology, and baseline CTU imaging. Safety and tolerability will be evaluated in patients who receive ≥1 dose of treatment. Enrollment is ongoing in Asia, Australia, Europe, North America, and South America. Clinical trial information: NCT02625961 .

Prognostic value of the Scottish Inflammatory prognostic Score in patients with NSCLC expressing PD-L1 ≥ 50 % progressing on first-line pembrolizumab

BackgroundMost patients with advanced non-small cell lung cancer (NSCLC) treated with first-line pembrolizumab monotherapy will experience progressive disease (PD). Only a minority will go on to receive subsequent systemic anticancer therapy for which outcomes are guarded. We investigated the prognostic significance of biomarkers of systemic inflammation following failure of first-line pembrolizumab for NSCLC to aid subsequent management decisions. MethodsPatients with radiological and/or clinical evidence of PD on first-line pembrolizumab for advanced NSCLC at a regional Scottish cancer centre were identified. Inflammatory biomarkers at the time of PD, including serum albumin, neutrophil count and the Scottish Inflammatory Prognostic Score (SIPS; combing albumin and neutrophils), and clinicopathological factors, including age, sex, histology, PDL1 expression and time to PD were recorded. The relationship between these and post-progression overall survival (ppOS) were examined. ResultsData were available for 211 patients. Median ppOS was 2.1 months. Only SIPS was predictive of ppOS on multivariate analysis (HR2.54 (95 %CI 1.81–3.56) (<0.001)), stratifying ppOS from 0.8 months (SIPS2), to 1.8 months (SIPS1), to 8.1 months (SIPS0) (p < 0.001). Thirty (14 %) patients received second-line systemic anticancer therapy with median ppOS 8.7 months. These patients had lower levels of systemic inflammation, as defined by albumin (p < 0.001), neutrophil count (p = 0.002), and SIPS (p = 0.004)), than all other patients. ConclusionsSIPS, a simple biomarker of systemic inflammation, predicts ppOS after first-line pembrolizumab and may be useful alongside routine assessments of patient fitness to inform individualised discussions about subsequent treatment. We highlight poor outcomes in this patient group and a role for SIPS in signposting transition to best supportive care and early referral to palliative care. It may also help identify a small group of patients most likely to benefit from further lines of therapy.

Comparison of efficacy and safety between domestic immune checkpoint inhibitors and pembrolizumab in the treatment of driver gene-negative advanced non-small cell lung cancer

Objective: To compare the efficacy and safety of domestic immune checkpoint inhibitors and pembrolizumab in the treatment of driver gene-negative advanced non-small cell lung cancer. Methods: A retrospective analysis was conducted on the data of 1 241 patients with driver gene-negative, unresectable stage ⅢB to Ⅳ non-small cell lung cancer who were treated at the Hunan Cancer Hospital from January 1, 2017 to October 1, 2022. All patients received monotherapy or combination therapy with domestic immune checkpoint inhibitors or pembrolizumab. Among the 1 241 patients, there were 1 066 males and 175 females, with an age range of 14 to 84 years and a median age of 62 years. Among them, 67 patients received monotherapy with domestic immune checkpoint inhibitors, 695 patients received combination therapy with domestic immune checkpoint inhibitors, 102 patients received monotherapy with pembrolizumab, and 377 patients received combination therapy with pembrolizumab. The efficacy and safety of domestic immune checkpoint inhibitors and pembrolizumab monotherapy or combination therapy were compared. Results: In the immune checkpoint inhibitor monotherapy group, the objective response rate (ORR) using domestic immune checkpoint inhibitors and pembrolizumab was 43.3%(29/67) and 44.1%(45/102), respectively, and the disease control rate (DCR) was 79.1%(53/67) and 84.3%(86/102), respectively, with no statistically significant differences (both P>0.05). In the immune combination therapy group, the ORR using domestic immune checkpoint inhibitors and pembrolizumab was 60.9%(423/695) and 62.9%(237/377), respectively, and the DCR was 92.9%(646/695) and 91.0%(343/377), respectively, with no statistically significant differences (both P>0.05). In the immune checkpoint inhibitor monotherapy group, the median progression-free survival (PFS) using domestic immune checkpoint inhibitors and pembrolizumab was 9.0 (95%CI: 3.0-15.0) months and 7.4 (95%CI: 4.8-9.8) months, respectively, with no statistically significant differences (P=0.660). The median overall survival (OS) was 27.0 (95%CI: 25.0-29.0) months and 22.0 (95%CI: 17.1-26.9) months, respectively, with no statistically significant differences (P=0.673). In the immune combination therapy group, the median PFS using domestic immune checkpoint inhibitors and pembrolizumab was 9.0 (95%CI: 8.2-9.8) months and 10.5 (95%CI: 9.0-12.0) months, respectively, with no statistically significant differences (P=0.186). The median OS was 24.0 (95%CI: 19.1-28.9) months and 26.0 (95%CI: 21.3-30.7) months, respectively, with no statistically significant differences (P=0.359). The incidence of grade 1-2 reactive capillary proliferation of the skin in the domestic immune checkpoint inhibitor group and pembrolizumab group was 14.0% (107/762) and 0, respectively. The incidence of grade≥3 reactive capillary proliferation of the skin was 1.0% (7/762) and 0, respectively, with statistically significant differences (both P<0.05). No statistically significant differences were observed in other adverse reactions (all P>0.05). Conclusions: The efficacy of domestically produced immune checkpoint inhibitors is comparable to that of pembrolizumab in the treatment of driver gene-negative advanced non-small cell lung cancer. There is little difference in safety, except for the specific difference in domestically produced immune checkpoint inhibitor, which has a unique risk of reactive cutaneous capillary endothelial proliferation.

Artificial intelligence (AI)-powered tumor microenvironment (TME) analysis to identify potential biomarkers for ICIs with or without bevacizumab in hepatocellular carcinoma (HCC).

549 Background: While immunotherapies have been approved for use in HCC patients, there is a need for validated predictive biomarkers that correlate with treatment outcomes. We investigated whether AI-powered spatial analysis of non-cancerous cells within the TME can be potential biomarkers for ICIs with or without bevacizumab in advanced HCC. Methods: Analysis of images of H&amp;E-stained slides was conducted by an AI model, Lunit SCOPE IO in pre-treatment tumor samples of 163 HCC patients treated with atezolizumab plus bevacizumab as first-line ( n=82), or monotherapies of nivolumab or pembrolizumab as ≥ second-line ( n=81) at CHA Bundang Medical Center or Samsung Medical Center. We analyzed the correlation between clinical outcomes after the treatment and AI-powered TME-related variables, including TILs and endothelial cells, within intratumoral or stromal areas. Inflamed immune phenotype (IIP) was defined as cases exhibiting enrichment of intratumoral TILs. Results: Baseline characteristics, including Child-Pugh liver classification, Barcelona Clinic Liver Cancer stage, and hepatitis B virus, were well-balanced between treatment regimens. IIP was predictive of longer progression-free survival (PFS) of nivolumab or pembrolizumab monotherapy (median PFS 4.7 months for IIP vs. 2.2 months for non-IIP; hazard ratio [HR] 0.50; 95% confidence interval [CI] 0.25-0.99; p=0.042), but not PFS of atezolizumab plus bevacizumab (median PFS 6.8 months vs. 6.2 months; HR 0.92; 95% CI 0.50-1.69; p=0.762). PFS of atezolizumab plus bevacizumab was significantly longer in cases harboring intratumoral endothelial cell density in the highest quartile (median PFS 6.7 months for upper 25% vs. 3.9 months for lower 75%; HR 0.51; 95% CI 0.27-0.97; p=0.037), while there was no significant difference in PFS of pembrolizumab or nivolumab monotherapy (median PFS 2.3 months vs. 2.8 months; HR 1.02; 95% CI 0.59-1.77; p=0.935). Conclusions: AI-powered TME analysis shows IIP is predictive of longer PFS with ICI monotherapies, whereas intratumoral endothelial cell density is specifically associated with PFS of atezolizumab plus bevacizumab in advanced HCC. The latter finding may suggest efficacy of combined VEGFRi and ICI activity is dependent on the amount of baseline tumor vasculature.

Immune-related adverse events in patients with gastrointestinal cancer undergoing pembrolizumab monotherapy: A systematic review of clinical trials.

744 Background: Pembrolizumab, an immune checkpoint inhibitor targeting programmed death 1 (PD-1), is widely employed in the treatment of various gastrointestinal (GI) cancers. This systematic review aims to assess the spectrum and incidence of immune-related adverse events (irAEs) associated with pembrolizumab monotherapy in GI cancer patients. Methods: A comprehensive search of PubMed/MEDLINE was conducted to identify full-text articles of clinical trials investigating pembrolizumab monotherapy in GI cancer patients. Two independent authors reviewed the articles and extracted data, with discrepancies resolved by consensus. Primary endpoints included the incidence of grade 3 or higher irAEs and the treatment discontinuation rate due to irAEs. Secondary endpoints encompassed the incidence of any-grade irAEs and specific irAEs such as pneumonitis, colitis, hepatitis, myositis, myocarditis, nephritis, pancreatitis, peripheral neuropathy, skin toxicity, endocrine toxicity, infusion reactions, and deaths. Results: After excluding duplicates and articles not meeting inclusion criteria, data extraction and analysis were performed on 25 selected articles. Common reasons for exclusion included concomitant use of chemotherapy or targeted therapy and trials involving non-GI cancer patients. The analysis included 2866 patients with a median age of 62 years, of which 29% were female. Tumor types included colorectal (13%), esophagogastric (46%), hepatocellular carcinoma (25%), and others (16%). The aggregate incidence of grade 3 or higher irAEs was 8.7%, with reported rates ranging from 3% to 41% across different trials. The incidence of any grade irAEs varied from 39% to 98%. The treatment discontinuation rate due to irAEs was 6.8%. The most common grade 3 or higher irAEs were hepatitis (3.6%), pneumonitis (0.8%), and colitis (0.7%). irAE-related deaths were infrequent (0.9%). Detailed irAE data are summarized in the Table. Conclusions: In GI cancer patients receiving pembrolizumab monotherapy, severe irAEs are rare. Treatment discontinuation and deaths attributed to pembrolizumab-related irAEs are infrequent, underscoring the safety profile of this therapy in patients with GI cancer. [Table: see text]