Programmed Death Ligand 1 Positive Tumor Research Articles

Efficacy of immune checkpoint inhibitors in advanced non-small cell lung cancer patients with rare KRAS mutations: a real-world retrospective study.

Kirsten rat sarcoma homolog (KRAS) mutations are one of the key drivers in non-small cell lung cancer (NSCLC) and FDA-approved specific inhibitors of KRAS-G12C mutation are available clinically. However, inhibitors of certain KRAS mutation subtypes remain unavailable, especially rare KRAS mutations including G13C, G13D, and Q61H. In this study, we retrospectively investigated the outcomes of NSCLC patients with rare KRAS-mutation to determine if they may benefit from immune checkpoint inhibitors (ICIs). Our retrospective study involved 240 advanced NSCLC patients with KRAS mutations, who visited Shanghai Chest Hospital from July 2018 to July 2021. Complete clinical and pathological data were recorded and progression-free survival (PFS) and overall survival (OS) were adopted as primary endpoints. The median follow-up time was 36.5 months (range, 30.8-42.1 months) and the median OS was 9.7 months (range, 7.6-11.8 months). Of the 240 patients evaluated, 130 (54.2%) received chemotherapy and 110 (45.8%) received ICI-based treatment. Among the patients who received chemotherapy, patients with rare KRAS-mutations presented worse survival outcomes (median PFS, 3.4 vs. 4.1 months, P=0.047; median OS, 5.2 vs. 7.1 months, P=0.02) than conventional KRAS-mutant patients. PFS and OS of rare KRAS-mutation patients were prolonged after immunotherapy (median PFS 7.3 vs. 3.4 months, P<0.001; median OS, 13.3 vs. 5.2 months, P<0.001) and had no significant difference compared with conventional KRAS-mutant patients, in part of them whose programmed death-ligand 1 (PD-L1) expression data before immunotherapy were available (n=72), patients with a higher rate of PD-L1 positive tumor cells (≥50%) presented elevated PFS and OS. Despite having potential survival disadvantage compared with other NSCLC patients, rare KRAS-mutant patients (other than G12A, C, D, V) could benefit specifically from ICI-based therapy and survival outcomes are correlated with PD-L1 expression.

Comparing deep learning and pathologist quantification of cell-level PD-L1 expression in non-small cell lung cancer whole-slide images

Programmed death-ligand 1 (PD-L1) expression is currently used in the clinic to assess eligibility for immune-checkpoint inhibitors via the tumor proportion score (TPS), but its efficacy is limited by high interobserver variability. Multiple papers have presented systems for the automatic quantification of TPS, but none report on the task of determining cell-level PD-L1 expression and often reserve their evaluation to a single PD-L1 monoclonal antibody or clinical center. In this paper, we report on a deep learning algorithm for detecting PD-L1 negative and positive tumor cells at a cellular level and evaluate it on a cell-level reference standard established by six readers on a multi-centric, multi PD-L1 assay dataset. This reference standard also provides for the first time a benchmark for computer vision algorithms. In addition, in line with other papers, we also evaluate our algorithm at slide-level by measuring the agreement between the algorithm and six pathologists on TPS quantification. We find a moderately low interobserver agreement at cell-level level (mean reader-reader F1 score = 0.68) which our algorithm sits slightly under (mean reader-AI F1 score = 0.55), especially for cases from the clinical center not included in the training set. Despite this, we find good AI-pathologist agreement on quantifying TPS compared to the interobserver agreement (mean reader-reader Cohen’s kappa = 0.54, 95% CI 0.26–0.81, mean reader-AI kappa = 0.49, 95% CI 0.27—0.72). In conclusion, our deep learning algorithm demonstrates promise in detecting PD-L1 expression at a cellular level and exhibits favorable agreement with pathologists in quantifying the tumor proportion score (TPS). We publicly release our models for use via the Grand-Challenge platform.

Assessment of PD-L1, TROP2, and nectin-4 expression in penile squamous cell carcinoma

ObjectivesThere is an unmet need for therapeutically relevant biomarkers for advanced penile squamous cell carcinoma (pSCC). Proposed immunohistochemistry (IHC)-based biomarkers include programmed death-ligand 1 (PD-L1), trophoblast cell-surface antigen 2 (TROP2), and nectin-4; however, there is a paucity of data pertaining to these biomarkers. Herein, we investigated the expression of PD-L1, TROP2, and nectin-4 in a well-annotated cohort of pSCCs. MethodsA single-institution pathology archive was queried for patients who had a partial or total penectomy for pSCC between January 2000 and December 2022. Whole-slide sections were stained with antibodies against PD-L1 (22C3), TROP2, and nectin-4. Expression in tumor cells was quantified using H-scores (0–300). Associations between IHC expression, human papilloma virus (HPV) status, clinicopathologic findings, and outcome parameters were evaluated. ResultsThis study included 121 patients. For PD-L1, the median combined positive and H-scores were 1 and 0, respectively; 32.7 % of the cases had an H-score>0. Compared to PD-L1–negative tumors, PD-L1–positive tumors had higher pT stage and grade. The median TROP2 and nectin-4 H-scores were 230 and 140, respectively, with high TROP2 and nectin-4, defined by an H-score>200, noted in 80.7 % and 10.9 % of cases, respectively. High-risk HPV–positive cases had higher TROP2 and nectin-4 scores compared to HPV–negative cases. Patients with high TROP2 expression had significantly more disease progression, and patients with high nectin-4 expression had significantly fewer deaths due to disease. ConclusionsHigh expression of TROP2 and nectin-4 in pSCC support evaluation of these markers as therapeutic targets pending validation of our findings.

Programmed death‑ligand 1 expression in tumor cells and tumor‑infiltrating lymphocytes are associated with depth of tumor invasion in penile cancer.

The present study aimed to demonstrate the proportion of the programmed death-ligand 1 (PD-L1) expression in penile cancer patients and the association with clinicopathological parameters. Formalin-fixed paraffin-embedded specimens were obtained from 43 patients with primary penile squamous cell carcinoma treated at Srinagarind Hospital, Faculty of Medicine, Khon Kaen University, between 2008 and 2018. PD-L1 expression was evaluated by the immunohistochemistry using an SP263 monoclonal antibody. PD-L1 positivity was defined as >25% tumor cell staining or >25% tumor-associated immune cell staining. The correlation between PD-L1 expression and clinicopathological parameters was analyzed. A total of eight of 43 patients (18.6%) were identified as positive for PD-L1 expression in tumor cells and tumor-infiltrating lymphocytes. In the PD-L1 positive group, there was a significant association with pathological T stage (P=0.014) with a higher percentage of PD-L1 positive tumors in T1 stage compared with T2-T4 stage. In this cohort, there was a trend towards longer survival in patients with positive PD-L1 expression (5-year OS: 75% vs. 61.2%, P=0.19). Lymph node involvement and the location of tumor at the shaft of penis were two independent prognostic factors for survival. In conclusion, the PD-L1 expression was detected in 18% of penile cancer patients and high expression of PD-L1 was associated with the early T stage.

Clinical Outcomes Associated With Pembrolizumab Monotherapy Among Adults With Diffuse Malignant Peritoneal Mesothelioma

Diffuse malignant peritoneal mesothelioma (DMPM) represents a rare and clinically distinct entity among malignant mesotheliomas. Pembrolizumab has activity in diffuse pleural mesothelioma but limited data are available for DMPM; thus, DMPM-specific outcome data are needed. To evaluate outcomes after the initiation of pembrolizumab monotherapy in the treatment of adults with DMPM. This retrospective cohort study was conducted in 2 tertiary care academic cancer centers (University of Pennsylvania Hospital Abramson Cancer Center and Memorial Sloan Kettering Cancer Center). All patients with DMPM treated between January 1, 2015, and September 1, 2019, were retrospectively identified and followed until January 1, 2021. Statistical analysis was performed between September 2021 and February 2022. Pembrolizumab (200 mg or 2 mg/kg every 21 days). Median progression-free survival (PFS) and median overall survival (OS) were assessed using Kaplan-Meier estimates. The best overall response was determined using RECIST (Response Evaluation Criteria in Solid Tumors) criteria, version 1.1. The association of disease characteristics with partial response was evaluated using the Fisher exact test. This study included 24 patients with DMPM who received pembrolizumab monotherapy. Patients had a median age of 62 years (IQR, 52.4-70.6 years); 14 (58.3%) were women, 18 (75.0%) had epithelioid histology, and most (19 [79.2%]) were White. A total of 23 patients (95.8%) received systemic chemotherapy prior to pembrolizumab, and the median number of lines of prior therapy was 2 (range, 0-6 lines). Of the 17 patients who underwent programmed death ligand 1 (PD-L1) testing, 6 (35.3%) had positive tumor PD-L1 expression (range, 1.0%-80.0%). Of the 19 evaluable patients, 4 (21.0%) had a partial response (overall response rate, 21.1% [95% CI, 6.1%-46.6%]), 10 (52.6%) had stable disease, and 5 (26.3%) had progressive disease (5 of 24 patients [20.8%] were lost to follow-up). There was no association between a partial response and the presence of a BAP1 alteration, PD-L1 positivity, or nonepithelioid histology. With a median follow-up of 29.2 (95% CI, 19.3 to not available [NA]) months, the median PFS was 4.9 (95% CI, 2.8-13.3) months and the median OS was 20.9 (95% CI, 10.0 to NA) months from pembrolizumab initiation. Three patients (12.5%) experienced PFS of more than 2 years. Among patients with nonepithelioid vs epithelioid histology, there was a numeric advantage in median PFS (11.5 [95% CI, 2.8 to NA] vs 4.0 [95% CI, 2.8-8.8] months) and median OS (31.8 [95% CI, 8.3 to NA] vs 17.5 [95% CI, 10.0 to NA] months); however, this did not reach statistical significance. The results of this retrospective dual-center cohort study of patients with DMPM suggest that pembrolizumab had clinical activity regardless of PD-L1 status or histology, although patients with nonepithelioid histology may have experienced additional clinical benefit. The partial response rate of 21.0% and median OS of 20.9 months in this cohort with 75.0% epithelioid histology warrants further investigation to identify those most likely to respond to immunotherapy.

275TiP ASCENT-03: Phase III study of sacituzumab govitecan (SG) vs treatment of physician’s choice (TPC) in first-line (1L) metastatic triple-negative breast cancer (mTNBC)

SG is a first-in-class antibody-drug conjugate composed of an anti-Trop-2 antibody coupled to a cytotoxic SN-38 payload via a proprietary, hydrolyzable linker. SG significantly improved outcomes over standard single-agent chemotherapy in patients (pts) with mTNBC who received ≥2 prior therapies (≥1 in the metastatic setting [Bardia et al. 2021]). Chemotherapy is the mainstay treatment option for 1L programmed death-ligand 1 (PD-L1)-negative mTNBC but is associated with poor outcomes. ASCENT-03 evaluates efficacy and safety of SG vs TPC in 1L locally advanced inoperable or mTNBC in pts with PD-L1-negative mTNBC irrespective of prior immune checkpoint inhibitors (ICI) in the early setting, or in PD-L1 positive mTNBC pts who received prior ICI in the early setting. ASCENT-03 (EudraCT: 2021-005743-79) is a global, open-label, randomized, phase III study in 1L locally advanced inoperable or mTNBC. This study includes pts with either PD-L1-negative tumors (combined positive score [CPS]<10) or PD-L1 positive tumors (CPS ≥ 10) who received an anti-PD-(L)1 inhibitor in the curative setting. TNBC (human epidermal growth factor receptor 2 negative, estrogen/progesterone receptor <1%) and PD-L1 status will be centrally confirmed. Other eligibility criteria include measurable disease; ≥6 mo since completion of treatment with curative intent; ECOG performance status 0-1. Pts are randomized 1:1 to receive SG (10 mg/kg IV on D1 and 8) in 21-d cycles or TPC (gemcitabine/carboplatin, paclitaxel, or nab-paclitaxel) until blinded independent central review (BICR)-verified progressive disease/unacceptable toxicity. Pts randomized to TPC may be eligible to cross over and receive SG upon disease progression. Pts are stratified by de novo vs recurrent disease within 6-12 mo of all treatment vs recurrent disease after >12 mo from completion of all treatment in the (neo)adjuvant setting; geographic region. The primary endpoint is progression-free survival by BICR per RECIST v1.1. Secondary endpoints include overall survival, objective response rate, quality of life, and safety. ASCENT-03 will enroll ∼540 patients and is open for recruitment. EudraCT 2021-005743-79. Gilead Sciences, Inc.

In vivo positron emission tomography imaging for PD-L1 expression in cancer using aptamer

The programmed death-1 (PD-1) receptor is an immunosuppressive receptor expressed on activated T-cells that elicits an inhibitory signal upon the engagement of its ligand, which is the programmed death ligand 1 (PD-L1). Recent studies have shown that PD-1/PD-L1 blockade can enhance endogenous antitumor immunity. Thus, the PD-1/PD-L1 axis may be a potential therapeutic target for cancer immunotherapy. Aptamers are oligonucleotides with high specificity and affinity for target molecules and promising candidates for molecular imaging and targeted therapy. 68Ga is an attractive radionuclide that serves as a low-cost alternative to cyclotron-produced positron emission tomography (PET) radionuclides. In this study, we developed a 68Ga-labeled PD-L1 aptamer and investigated its target specificity and utility for in vivo PET scanning. In the first part of our study, we evaluated the binding affinity of three PD-L1 aptamers in PD-L1-positive (H1975 and B16F10) and negative (A549 and HT-29) tumor cells by flow cytometry and confocal microscopy. Optical imaging studies of PD-L1 aptamers were performed in H1975 tumor-bearing mice, and the aptamer with the highest binding affinity to PD-L1 positive tumors was selected. PD-L1 aptamers were radiolabeled with 68Ga. PET was performed for in vivo imaging of the 68Ga-NOTA-PD-L1 aptamer in H1975 tumor-bearing mice (PD-L1-positive cells) and A549 tumor-bearing mice (PD-L1-negative cells). Flow cytometry and confocal microscopy showed that PD-L1 aptamers had strong binding to PD-L1-positive H1975 and B16F10 cells. In contrast, PD-L1-negative A549 and HT-29 cells showed low binding to PD-L1 aptamers. Optical imaging studies of H1975 tumor-bearing mice showed the highest uptake of the 2198-06-07 PD-L1 aptamer. PET of 68Ga-NOTA-PD-L1 aptamers demonstrated increased uptake into PD-L1-positive H1975 tumors compared with PD-L1-negative A549 tumors. We confirmed that 68Ga-NOTA-PD-L1 aptamers facilitated the visualization of PD-L1 expression by in vivo PET scanning. These data suggest that 68Ga-NOTA-PD-L1 aptamers could potentially act as tracers for imaging for PD-L1-positive cancers.

Observer performance study to examine the feasibility of the AI-powered PD-L1 analyzer to assist pathologists’ assessment of PD-L1 expression using tumor proportion score in non–small cell lung cancer.

8529 Background: Programmed death ligand 1 (PD-L1) expression is the standard biomarker for PD-L1 inhibitors in advanced non-small cell lung cancer (NSCLC). However, evaluation of PD-L1 tumor proportion score (TPS) by pathologists causes inter-observer variation and demands time to interpret. This study aimed to evaluate the benefit of the artificial intelligence (AI) algorithm in assisting pathologists to determine TPS on PD-L1 immunohistochemistry (IHC) whole-slide images (WSIs) in NSCLC. Methods: Lunit SCOPE PD-L1, an AI-powered PD-L1 TPS analyzer, was developed from 393,565 tumor cells annotated by board-certified pathologists for PD-L1 expression in 802 WSIs stained by 22C3 pharmDx IHC. The AI model was developed based on a region-based convolutional neural network, and the model can detect and count PD-L1 positive or negative tumor cells from WSIs to calculate TPS. Seven independent board-certified pathologists scored ground truth (GT) of PD-L1 TPS from 199 WSI of NSCLC stained by 22C3 pharmDx IHC. TPS from each GT reader was grouped as negative (&lt; 1%), low (1% to 49%), or high (≥ 50%). The GT of each slide was determined by the consensus of GT readers. Another twelve independent board-certified pathologists scored PD-L1 TPS from the same WSIs as observer performance testers (OPT). They scored TPS twice with a washout interval of 4 weeks, with or without AI assistance. TPS accuracy change and reading time of OPT reader according to the presence or absence of AI assistance were analyzed. Results: The standalone accuracy of the AI model was 0.809 (95% CI: 0.690–0.941). With AI assistance, the overall accuracy of TPS had been changed from 0.799 (95% confidence interval [CI]: 0.764–0.836) to 0.832 (95% CI: 0.796–0.869) (P = 0.004). AI assistance increased the accuracy rate in 11 out of 12 OPT readers. The result of the generalized linear mixed model revealed that AI assistance and specimen type affected the probability of correct answer, while the order of reading did not (Table). The mean time to read with AI was 195.4±506.5 (mean±standard deviation) seconds, which was significantly shorter than the mean time to read without AI (285.1±1578.4, P &lt;0.001). Conclusions: This study demonstrates that an AI-powered PD-L1 TPS analyzer can assist board-certified pathologists in evaluating TPS of NSCLC by improving the accuracy of TPS group evaluation and reducing the time to read slides.[Table: see text]

Expanding the immunotherapy roadmap for hepatocellular carcinoma.

In a recent Lancet Oncology article, Yau etal. report the CheckMate 459 trial results. This is the first phase III trial comparing the single-agent anti-programmed death protein 1 (PD-1) therapy nivolumab to the tyrosine kinase inhibitor sorafenib for treatment-naive patients with advanced hepatocellular carcinoma.

Analysis of disease-free survival in CheckMate 274 by PD-L1 combined positive score and tumor proportion score.

491 Background: CheckMate 274 demonstrated a significant improvement in disease-free survival (DFS) with nivolumab (NIVO) versus placebo (PBO) both in the intent-to-treat population (hazard ratio [HR], 0.70; 98.22% confidence interval [CI], 0.55–0.90; P &lt; 0.001) and in patients (pts) with tumor programmed death ligand 1 (PD-L1) expression ≥ 1% assessed by the tumor proportion score (TPS) (HR, 0.55; 98.72% CI, 0.35–0.85; P &lt; 0.001). An exploratory subgroup analysis showed a trend toward a DFS benefit with NIVO in pts with TPS &lt; 1% (0.82; 95% CI, 0.63–1.06). To further characterize the relationship between PD-L1 expression and NIVO efficacy, we report an analysis of DFS based on PD-L1 expression in both tumor and immune cells using the combined positive score (CPS). Methods: CheckMate 274 is a phase 3, randomized, double-blind, multicenter trial of NIVO versus PBO in pts with high-risk muscle-invasive urothelial carcinoma after radical surgery. Pts were randomized 1:1 to NIVO 240 mg or PBO every 2 weeks intravenously for 1 year of adjuvant treatment. The primary endpoints of the study are DFS in the intent-to-treat population and in pts with TPS ≥ 1%. The Dako PD-L1 IHC 28-8 pharmDx assay was used to evaluate TPS. CPS was determined retrospectively from previously stained immunohistochemistry slides using the CPS algorithm. CPS was calculated as the number of both PD-L1 positive tumor and immune cells divided by the number of viable tumor cells in the evaluable tumor area, multiplied by 100; TPS was similarly calculated with the number of PD-L1 positive tumor cells as the numerator. This analysis only included pts with both quantifiable CPS and TPS. Results: Of the 629 pts with quantifiable TPS and CPS, 249 (40%) had TPS ≥ 1% (NIVO, n = 124; PBO, n = 125), 380 (60%) had TPS &lt; 1% (NIVO, n = 191; PBO, n = 189), 557 (89%) had CPS ≥ 1 (NIVO, n = 281; PBO, n = 276), and 72 (11%) had CPS &lt; 1 (NIVO, n = 34; PBO, n = 38). Within TPS &lt; 1% pts, 81% (n = 309) had CPS ≥ 1. The number of pts and the DFS outcomes in pts with TPS ≥ 1% and CPS ≥ 1 are shown in the Table. In pts with TPS &lt; 1% who also had CPS ≥ 1, median DFS (95% CI) was 19.2 (15.6–33.4) months with NIVO versus 10.1 (8.2–19.4) months with PBO. The HR for NIVO versus PBO in these pts was 0.73 (95% CI, 0.54–0.99). Conclusions: This exploratory analysis of PD-L1 expression by CPS showed a higher proportion of pts with CPS ≥ 1 than TPS ≥ 1%, and that most pts with TPS &lt; 1% had CPS ≥ 1. In the CPS ≥ 1 subgroup, median DFS with NIVO was more than double that with placebo. These results support the conclusion that pts with TPS &lt; 1% also benefit from adjuvant NIVO. Clinical trial information: NCT02632409. [Table: see text]

Abstract ES10-3: IO beyond TNBC

Abstract Hormone receptor-positive breast cancer is not considered an immunogenic tumor, since characterized by lower level of programmed death-ligand 1 (PD-L1) expression and tumor infiltrating lymphocytes. Despite being a cold tumor some studies are addressing the question on potential role of immune-checkpoint inhibitors in the adjuvant or metastatic setting. The phase II Checkmate7A8 trial (NCT04075604) is investigating the combination of nivolumab, anastrozole, and palbociclib versus anastrozole with palbociclib as neoadjuvant therapy for postmenopausal women with luminal BC. The phase II ImmunoADAPT trial (NCT03573648) is studying the combination of tamoxifen, palbociclib, and avelumab versus tamoxifen with avelumab for patients with early-stage luminal BC, expecting to show an improvement in the radiological complete response rates assessed after four cycles of treatment. A phase I safety study is also investigating the combination of durvalumab, abemaciclib, and anastrozole in a similar population (NCT04088032). The Phase 3 CA209-7FL trial is a randomized, multicenter, placebo-controlled phase 3 study of nivolumab versus placebo in combination with neoadjuvant chemotherapy and adjuvant endocrine therapy in patients with high-risk, estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2-) primary breast cancer. In the HER2 positive metastatic breast cancer the combination of pembrolizumab and trastuzumab administered upon progression on a trastuzumab-based regimen was investigated in the PANACEA study, which reported a response rate of 15%, restricted to PD-L1 positive tumors with a PFS benefit in the PD-L1 population. In the KATE2 trial, the addition of atezolizumab to trastuzumab emtansine in patients previously treated with trastuzumab demonstrated no significant benefit in PFS, although numerically higher PFS and response rates were observed in the PD-L1-positive population. A subsequent underpowered analysis (due to the small number of events) of the same trial suggested a possible OS benefit for patients with PD-L1-positive tumors. The combination of trastuzumab, pertuzumab, taxane, and atezolizumab is under investigation in the first-line setting (NCT03199885). The phase III IMpassion050 (NCT03726879) trial compares atezolizumab or placebo combined with neoadjuvant chemotherapy and dual anti-HER2 blockade for early-stage HER2-positive BC. This trial includes patients with PD-L1-positive and PD-L1-negative tumors and is considering pCR rates in the PD-L1-positive and ITT population as primary endpoints. In patients who do not achieve a pCR, TDM-1 is added in the adjuvant phase. The addition of atezolizumab to an anthracycline-free regimen of neoadjuvant chemotherapy and dual anti-HER2 blockade is the objective of the phase III APTneo trial (NCT035955592). In my presentation I will cover biological rational for IO studies beyond triple negative breast cancer in the attempt to provide an ideal immunogram for this population of patients. Citation Format: G Curigliano. IO beyond TNBC [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr ES10-3.

PD-L1 expression and its clinicopathologic and genomic correlation in the non-small cell lung carcinoma patients: An Indian perspective

BackgroundImmunotherapy with checkpoint inhibitor programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) antibodies targeting the cellular immune checkpoints is the present area of interest showing promising results in patients with advanced non-small cell lung cancer (NSCLC). As there is paucity of PD-L1 expression data from the Indian perspective, we studied the correlation of clinicopathologic profile and oncogenic driver mutations in these patients. Materials and methodsSamples from 252 advanced NSCLCs patients were studied for PD-L1 expression through immunohistochemistry using rabbit anti-human PD-L1 monoclonal antibody (clone SP263) on Ventana BenchMark ULTRA autostainer. Simultaneously, genetic mutations were studied by next generation sequencing (for EGFR, ALK, ROS, MET, and BRAF). PD-L1 expression was analyzed for association with clinicopathologic features and various mutations. ResultsPD-L1 positivity was seen in 134 patients (53.2 %). It was twice more prevalent in males than females. No significant correlation was observed between PD-L1 expression with age, gender, site of testing (primary vs. metastatic tumors), smoking status, tumor laterality, stage, or histologic type; however, there was significant difference among solid and acinar types of adenocarcinoma combined together vs. other adenocarcinoma subtypes (p = 0.013), and well and moderately differentiated vs. poorly differentiated tumors (p = 0.022). When types/extent of PD-L1 positivity (≥25 %) were compared with demographics, clinical, and pathologic variables, significant differences were observed across the tumor grades (high-grade vs. low-grade) (p = 0.009) and stages (p = 0.039). The PD-L1 expression failed to demonstrate any statistical significance with oncogenic drivers. High PD-L1 expression (TPS ≥ 50) was observed in 27.6 % patients, and it was more prevalent in female patients (32.4 %), aged ≥60 years (33.8 %), smokers (27.3 %), poorly differentiated (36.8 %) and stage IV tumors (28.2 %). Exon 19 deletion was more prevalent in PD-L1 negative tumors whereas exon 21 substitution (L858R) was seen more in PD-L1 positive tumors. ConclusionsThis is the largest Indian study demonstrating PD-L1 expression in NSCLC patients comparing with clinicopathologic and genomic parameters. PD-L1 expression was significantly associated with high-grade, solid, and acinar types of adenocarcinoma and advanced tumors. High PD-L1 expression was more prevalent in female patients, aged ≥60 years, smokers, and poorly differentiated and stage IV tumors (28.2 %). Exon 19 deletion was more in PD-L1 negative tumors whereas exon 21 substitution (L858R) was more in PD-L1 positive tumors. PD-L1 is a potential predictive marker stratifying patients who benefit from PD-1 pathway-targeted therapy.

Analyses of PD-L1 and Inflammatory Gene Expression Association with Efficacy of Nivolumab ± Ipilimumab in Gastric Cancer/Gastroesophageal Junction Cancer

In advanced gastric cancer/gastroesophageal junction cancer (GC/GEJC), there is a need to identify biomarkers of response to therapies, such as immune checkpoint inhibitors. In post hoc exploratory analyses from CheckMate 032 (GC/GEJC cohort), we evaluated associations between nivolumab ± ipilimumab (NIVO ± IPI) efficacy and programmed death ligand 1 (PD-L1) expression, defined by tumor cells (% TC) or combined positive score (CPS; sum of PD-L1-staining TCs + immune cells, divided by total viable TCs, × 100) using the Dako PD-L1 IHC 28-8 pharmDx assay, or inflammatory gene expression. There was a trend toward increased efficacy (objective response and overall survival) when PD-L1 expression was determined by CPS compared with % TC at higher cutoffs of ≥5 and ≥10 in the pooled analysis of all treatment regimens. In this analysis, 19% and 26% of patients with PD-L1-positive tumors at a CPS cutoff of ≥5 and ≥10, respectively, had an objective response compared with 8% and 9% of patients at the equivalent % TC cutoffs. Longer survival was demonstrated in patients with PD-L1-positive (defined by CPS cutoffs of ≥5 and ≥10) versus PD-L1-negative status. Similar results were observed in the NIVO 1 mg/kg + IPI 3 mg/kg subgroup. Multiple inflammatory gene signatures/transcripts, including a signature consisting of four genes (CD274, CD8A, LAG3, and STAT1), showed associations with response to NIVO ± IPI. This study suggests a greater association of PD-L1 expression by CPS with NIVO ± IPI efficacy compared with % TC PD-L1 expression in patients with GC/GEJC. Inflammatory signatures were also associated with NIVO ± IPI response, warranting further investigation.See related commentary by Moutafi and Rimm, p. 3812.

Effects of immunohistochemical conditions on the results of PD-L1 (22C3) staining

Objective: To investigate the optimal experimental conditions (including antigen retrieval time, antibody titers and antibody incubation time) for reliable detection of programmed death-ligand 1 (PD-L1) expression using PD-L1 (22C3) antibody concentrate, and to establish a laboratory developed test for PD-L1 detection. Methods: Using Dako PD-L1 IHC 22C3 pharmDX staining procedure and scoring guidelines as the standard reference (group A), the PD-L1 expression in 25 tissue specimens (including 15 lung cancer tissues, 5 tonsil tissues and 5 placenta tissues) was detected with Flex+/HRP detection kit (EnVision) under 8 different experimental conditions (groups B1 to B8). The staining results were then compared to those in group A. Results: In group B1, 3 tissue samples showed the percentages of PD-L1 positive tumor cells were similar to those in group A, while the percentages of PD-L1 positive tumor cells were lower than those in group A in the other samples. In group B7, two case showed a positive rate higher than that in group A that was also above the positive cut-off value, and the rest of the samples had a percentage of PD-L1 positive tumor cells slightly higher than that in group A, but still below the positive cut-off value. The staining results of group B8 were the closest to those of group A compared with the other groups. Although the percentages of PD-L1 positive tumor cells in the B2 to B6 groups were decreased in various degrees as compared with group A, they were still concordant with group A's classification (positive vs. negative) and would not change the choice of clinical treatments. Conclusions: The experimental conditions are associated with detection rate of PD-L1 expression using 22C3 antibody. In the present study, the most-suitable alterative conditions in the PD-L1 detection using 22C3 antibody concentrate are those applied in the group B8 (including antigen retrieval in Dako PT Link tank at 97 ℃, pH 6.0 for 40 min and incubation with 22C3 antibodies (1∶100 dilution) at room temperature for 60 min, incubation with EnVision Flex+Linker at room temperature for 30 min, incubation with EnVision/HRP at room temperature for 30 min and DAB staining for 5 min), which could provide reliable results at minimum costs.

Enhanced efficacy of mesothelin-targeted immunotoxin LMB-100 and anti-PD-1 antibody in patients with mesothelioma and mouse tumor models.

LMB-100 is an immunotoxin targeting the cell surface protein mesothelin, which is highly expressed in many cancers including mesothelioma. Having observed that patients receiving pembrolizumab off protocol after LMB-100 treatment had increased tumor responses; we characterized these responses and developed animal models to study whether LMB-100 made tumors more responsive to antibodies blocking programmed cell death protein 1 (PD-1). The overall objective tumor response in the 10 patients who received PD-1 inhibitor (pembrolizumab, 9; nivolumab, 1) after progression on LMB-100 was 40%, and the median overall survival was 11.9 months. Of the seven evaluable patients, four had objective tumor responses, including one complete response and three partial responses, and the overall survival for these patients was 39.0+, 27.7, 32.6+, and 13.8 months. When stratified with regard to programmed death ligand 1 (PD-L1) expression, four of five patients with tumor PD-L1 expression had objective tumor response. Patients with positive tumor PD-L1 expression also had increased progression-free survival (11.3 versus 2.1 months, P = 0.0018) compared with those lacking PD-L1 expression. There was no statistically significant difference in overall survival (27.7 versus 6.8 months, P = 0.1). LMB-100 caused a systemic inflammatory response and recruitment of CD8+ T cells in patients' tumors. The enhanced antitumor effects with LMB-100 plus anti-PD-1 antibody were also observed in a human peripheral blood mononuclear cell-engrafted mesothelioma mouse model and a human mesothelin-expressing syngeneic lung adenocarcinoma mouse model. LMB-100 plus pembrolizumab is now being evaluated in a prospective clinical trial for patients with mesothelioma.

Guidance and best practices for nuclear cardiology laboratories during the coronavirus disease 2019 (COVID-19) pandemic: An Information Statement from ASNC and SNMMI

1022 Purpose: The programmed death-ligand 1 (PD-L1) immunohistochemistry correlates moderately with the response to PD-L1 immunomodulatory therapy. Here we present the initial results from the studies to assess the feasibility of non-invasive PD-L1 imaging with 68Ga-WL12 (a 12-mer anti-PD-L1 peptide) radiotracer from animal experiments to the first-in-human study. Methods: PD-L1 binding peptide, NOTA-WL12, was synthesized by custom services with >95% chemical purity. , we generated 68Ga-WL12 with high specific radioactivity and radiochemical purity. We select human non-small cell lung cancer cells ( HCC827) , which with moderate expression of PD-L1. To demonstrate PD-L1-specific binding of 68Ga-WL12, both binding affinity test and cell uptakes were carried out with excess WL12. Normal Mice were used for PET/CT imaging and biodistribution study. Finally, we recruited a patient ( 80 years old female ;ethical approval No.2019KT) with non-small cell lung cancer who was positive for PD-L1(>80%) and performed PET/CT imaging with 68Ga-WL12 before and after immunomodulatory therapy. Results: To demonstrate PD-L1 specificity and cell uptake, we generated 68Ga-WL12 with radiochemical purity >99% after purification, specific activity 27.8-111.2 GBq/umol. High 68Ga-WL12 uptake was observed in PD-L1-positive HCC827 cells. TO confirming radiotracer specificity, we observed a significant reduction in bound 68Ga-WL12 in the presence of the excess unmodified peptide, indicating that 68Ga-WL12 binding to PD-L1 is specific. We performed PET imaging of the tumor model with 68Ga-WL12. The uptake value was consistent with tracer biodistribution. Finally, in this first-in-human assessment of 68Ga-WL12, we show that the imaging signal corresponds to PD-L1 expression at sites of the primary tumor and metastatic focus. The SUVpeak of different tumor lesions ranged from 2.0 to 6.0. The SUV value of PD-L1 positive tumors decreased significantly after immunomodulatory therapy. Conclusions: In this study, we demonstrated that 68Ga-WL12 exhibited a high affinity to PD-L1 in the Cell uptake experiment in vitro. 68Ga-WL12 demonstrated PD-L1 specific uptake first-in-human study. Therefore, 68Ga-WL12 PET/CT imaging may be a useful tool to assess PD-L1 expression in lesions. Future clinical studies are needed to confirm our findings in a larger patient population, to comprehensively assess different 68Ga-WL12 uptake features in combination with other clinical data to optimize therapy response prediction, and to evaluate whether 68Ga-WL12 PET could also be used as a response predictor for treatment with other monoclonal antibodies targeting the PD-1/PD-L1 axis.

Guidance and best practices for nuclear cardiology laboratories during the coronavirus disease 2019 (COVID-19) pandemic: An Information Statement from ASNC and SNMMI.

1022 Purpose: The programmed death-ligand 1 (PD-L1) immunohistochemistry correlates moderately with the response to PD-L1 immunomodulatory therapy. Here we present the initial results from the studies to assess the feasibility of non-invasive PD-L1 imaging with 68Ga-WL12 (a 12-mer anti-PD-L1 peptide) radiotracer from animal experiments to the first-in-human study. Methods: PD-L1 binding peptide, NOTA-WL12, was synthesized by custom services with >95% chemical purity. , we generated 68Ga-WL12 with high specific radioactivity and radiochemical purity. We select human non-small cell lung cancer cells ( HCC827) , which with moderate expression of PD-L1. To demonstrate PD-L1-specific binding of 68Ga-WL12, both binding affinity test and cell uptakes were carried out with excess WL12. Normal Mice were used for PET/CT imaging and biodistribution study. Finally, we recruited a patient ( 80 years old female ;ethical approval No.2019KT) with non-small cell lung cancer who was positive for PD-L1(>80%) and performed PET/CT imaging with 68Ga-WL12 before and after immunomodulatory therapy. Results: To demonstrate PD-L1 specificity and cell uptake, we generated 68Ga-WL12 with radiochemical purity >99% after purification, specific activity 27.8-111.2 GBq/umol. High 68Ga-WL12 uptake was observed in PD-L1-positive HCC827 cells. TO confirming radiotracer specificity, we observed a significant reduction in bound 68Ga-WL12 in the presence of the excess unmodified peptide, indicating that 68Ga-WL12 binding to PD-L1 is specific. We performed PET imaging of the tumor model with 68Ga-WL12. The uptake value was consistent with tracer biodistribution. Finally, in this first-in-human assessment of 68Ga-WL12, we show that the imaging signal corresponds to PD-L1 expression at sites of the primary tumor and metastatic focus. The SUVpeak of different tumor lesions ranged from 2.0 to 6.0. The SUV value of PD-L1 positive tumors decreased significantly after immunomodulatory therapy. Conclusions: In this study, we demonstrated that 68Ga-WL12 exhibited a high affinity to PD-L1 in the Cell uptake experiment in vitro. 68Ga-WL12 demonstrated PD-L1 specific uptake first-in-human study. Therefore, 68Ga-WL12 PET/CT imaging may be a useful tool to assess PD-L1 expression in lesions. Future clinical studies are needed to confirm our findings in a larger patient population, to comprehensively assess different 68Ga-WL12 uptake features in combination with other clinical data to optimize therapy response prediction, and to evaluate whether 68Ga-WL12 PET could also be used as a response predictor for treatment with other monoclonal antibodies targeting the PD-1/PD-L1 axis.

Pembrolizumab After Two or More Lines of Previous Therapy in Patients With Recurrent or Metastatic SCLC: Results From the KEYNOTE-028 and KEYNOTE-158 Studies.

Pembrolizumab has shown clinical benefit in patients with previously treated recurrent or metastatic SCLC in the phase 1b multicohort study KEYNOTE-028 (NCT02054806) and the phase 2 multicohort study KEYNOTE-158 (NCT02628067). We present a pooled analysis of patients from KEYNOTE-028 and KEYNOTE-158 who had received two or more lines of previous therapy for SCLC. Eligible patients were aged 18 years and above, had histologically or cytologically confirmed incurable recurrent or metastatic SCLC, had an Eastern Cooperative Oncology Group performance status of 1 and below, and had received two or more lines of previous therapy. Patients in KEYNOTE-028 were required to have a programmed death ligand 1 (PD-L1)-positive tumor. Patients received pembrolizumab (10 mg/kg every 2 weeks in KEYNOTE-028 or 200 mg every 3 weeks in KEYNOTE-158) for up to 2 years. The primary end point was objective response rate per Response Evaluation Criteria in Solid Tumors version 1.1, which is presented here per independent review. Eighty-three patients who had received two or more lines of previous therapy (KEYNOTE-028, n= 19; KEYNOTE-158, n= 64) were included. Median follow-up duration was 7.7 (range, 0.5-48.7) months. Objective response rate was 19.3% (95% confidence interval: 11.4-29.4); two patients had complete response (one with a PD-L1-positive tumor), and 14 patients had partial response (13 with PD-L1-positive tumors). The median duration of response was not reached (range, 4.1‒35.8+ mo; plus sign indicates ongoing response); 61% of responders had responses lasting 18 months or longer. Fifty-one patients (61.4%) experienced any-grade treatment-related adverse events; eight patients (9.6%) had grade 3 or higher events. Pembrolizumab exhibited durable antitumor activity in a subset of patients with recurrent or metastatic SCLC who had undergone two or more previous lines of therapy, regardless of PD-L1 expression. Pembrolizumab was well tolerated.

Patterns and genomic correlates of PD-L1 expression in patients with biliary tract cancers.

Patients with biliary tract cancer (BTC) have a dismal prognosis and limited treatment options. Given the potential for immunotherapy in patients with BTC, we studied the expression of programmed death ligand-1 (PD-L1)/programmed death-1 (PD-1) and evaluated for associated genetic alterations in patients with BTC. By immunohistochemistry (IHC), PD-L1 (SP142 antibody; ≥2+ and/or ≥5% staining on tumor cells considered positive) and PD-1 [NAT105 antibody; ≥1+ staining of tumor infiltrating lymphocytes (TILs) considered positive] expression was studied and next-generation sequencing (NGS) was performed using Caris Life Sciences' sequencing panel of 592 genes. A total of 652 patients with BTC were included in this study: 77 extrahepatic cholangiocarcinoma (ECC), 203 gallbladder cancer (GBC), and 372 intrahepatic cholangiocarcinoma (ICC). Of the 652 tumors 8.6% were PD-L1 positive with the following distribution: GBC 12.3% (25/203), ICC 7.3% (27/372), and ECC 5.2% (4/77). There was a statistically significant increase in BRAF, BRCA2, RNF43, and TP53 mutations in PD-L1 positive group as compared to PD-L1 negative. Among other biomarkers tested, TOP2A, tumor mutational burden (TMB) high (≥17 mutations per megabase) (10.7%), and microsatellite instability high (MSI-H) (7.1%) were increased in PD-L1 positive tumors versus PD-L1 negative tumors. PD-L1 expression was noted in a small percentage (8.6%) of patients with BTC. This finding suggests potential benefit of immunotherapy in this subset of patients. Furthermore, there was a statistically significant association between PD-L1 expression and certain genomic alterations (BRAF, BRCA2, RNF43, TP53) and biomarkers (TOP2A, TMB high, MSI-H), which might direct the use of rational combination strategies and clinical trial development.

1714P - PD-L1 expression as a potential therapeutic target and prognostic biomarker in well-differentiated and dedifferentiated liposarcoma

BackgroundFor liposarcoma (LPS), the mainstay of treatment is still surgical resection. Recently, some researchers suggested that immune checkpoint inhibitor may have a clinical activity in well-differentiated (WD) and dedifferentiated (DD) LPS. We aimed to evaluate the expression level of programmed death ligand 1 (PD-L1) and determine its relationship with clinical outcomes in WD/DD LPS. MethodsAll patients diagnosed with WD/DD LPS at Asan medical center from 1989 to 2017 were identified and their clinical information were obtained from our medical database. PD-L1 testing was performed with previously-collected surgery or biopsy tissue by Immunohistochemistry (IHC). ResultsTotal 152 patients who were pathologically diagnosed with WD (n=74) or DD (n=78) LPS and had available tissue for PD-L1 IHC assay were included in this retrospective analysis. The median age was 58 years (range, 19—87) with males comprising 59.2%. By primary site, abdomen-pelvis (69.7%) was most frequently involved. Most patients (98.7%, n=150) were presented with localized disease at the time of diagnosis and every patient with localized disease except one with high-perioperative risk (n=149) underwent curative-intent surgical resection. PD-L1 positive (tumor proportion score ≥1%) rate was 31.1% and 51.3% in WD and DD LPS, respectively. In WD LPS, PD-L1 positivity, as well as abdomen-pelvis origin, R1/2 resection, and no adjuvant radiotherapy, was associated with shorter recurrence-free survival (RFS) (vs. PD-L1 negativity, 31.3 vs. 99.8 months; P=0.014) and remained significant in the multivariate analysis (HR, 2.7, P=0.028). In DD LPS, on the other hand, PD-L1 expression had no statistical significance in multivariate model for RFS. Overall survival was not properly compared due to the small number of death events. ConclusionsOur findings indicate that decent portion of WD/DD LPS patients were positive for PD-L1 expression, and it might be a negative prognostic biomarker in surgically-resected WD LPS. This provides a rationale for future clinical trials of immune checkpoint inhibitor for patients with PD-L1-positive WD/DD LPS. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.