First-line Pembrolizumab Research Articles

First-Line Lenvatinib Plus Pembrolizumab for Hepatocellular Carcinoma: Post Hoc Analysis of Japanese Patients From the Phase 3 LEAP-002 Trial

First-Line Lenvatinib Plus Pembrolizumab for Hepatocellular Carcinoma: Post Hoc Analysis of Japanese Patients From the Phase 3 LEAP-002 Trial

Pembrolizumab 400 mg every 6 weeks as first-line therapy for advanced melanoma (KEYNOTE-555): Results from cohort B of an open-label, phase 1 study.

Intravenous pembrolizumab 400 mg every 6 weeks was approved across tumor types based on pharmacokinetic modeling, which showed exposures consistent with previous standard dosing of 200 mg or 2 mg/kg every 3 weeks, and early results of cohort B of the phase 1 KEYNOTE-555 study. Results after ≥1 year of potential follow-up for all patients in cohort B of KEYNOTE-555 are presented. Patients aged ≥18 years with previously untreated stage III/IV melanoma received pembrolizumab 400 mg every 6 weeks for ≤18 cycles. The primary endpoint was objective response rate per RECIST v1.1 by blinded independent central review. Secondary endpoints included duration of response, progression-free survival, pharmacokinetics, and safety. Overall, 101 patients received pembrolizumab. Median projected follow-up was 21.9 months (range, 17.0-25.7). The objective response rate was 50.5% (95% CI: 40.4-60.6; 19 complete responses, 32 partial responses). Median duration of response was not reached (NR; range, 2.4+ to 21.0+ months). Median progression-free survival was 13.8 months (95% CI: 4.1-NR). Observed pharmacokinetic exposures were consistent with model predictions for pembrolizumab 400 mg every 6 weeks and other approved and tested schedules (2 mg/kg or 200 mg every 3 weeks). Grade 3-4 treatment-related adverse events occurred in 13 patients (12.9%). No deaths were considered treatment related. These results support the pharmacokinetic modeling and demonstrate that the benefit-risk profile of pembrolizumab 400 mg Q6W is consistent with that of 200 mg or 2 mg/kg every 3 weeks. Clinically meaningful objective response rate and durable progression-free survival within the expected range for first-line pembrolizumab were observed. Clinical trial registry: ClinicalTrials.gov, NCT03665597.

Cisplatin- or Carboplatin-Based Chemotherapy Plus Pembrolizumab in Advanced Urothelial Cancer: Exploratory Analysis From the Phase 3 KEYNOTE-361 Study

IntroductionKEYNOTE-361 evaluated first-line pembrolizumab with and without platinum-based chemotherapy versus chemotherapy alone in advanced or metastatic urothelial carcinoma. The primary end points of progression-free survival (PFS) or overall survival (OS) were not met. Exploratory analysis of efficacy by platinum agent (cisplatin or carboplatin) is reported. Patients and MethodsEligible patients were randomly assigned 1:1:1 to receive pembrolizumab 200 mg intravenously every 3 weeks for ≤35 cycles with or without chemotherapy (gemcitabine with investigator's choice of either cisplatin or carboplatin) or chemotherapy alone. This exploratory subset analysis evaluated PFS and objective response rate (ORR) per RECIST v1.1 by blinded independent central review and OS for cisplatin- or carboplatin-based chemotherapy with versus without pembrolizumab for patients assigned to chemotherapy-containing arms of KEYNOTE-361. ResultsOf 1010 patients enrolled, 703 were assigned to receive a chemotherapy-containing regimen (n = 312 cisplatin based; n = 391 carboplatin based). Median follow-up was 31.3 months. For cisplatin-based arms, with versus without pembrolizumab, median OS was 20.1 versus 16.4 months (HR 0.88, 95% CI 0.67-1.15) and median PFS was 8.5 versus 7.1 months (HR 0.67, 0.51-0.89). ORR was 64.1% versus 48.7%, respectively. For carboplatin-based arms, with versus without pembrolizumab, median OS was 15.5 versus 12.3 months (HR 0.84, 95% CI 0.67-1.06) and median PFS was 8.0 versus 6.7 months (HR 0.86, 0.68-1.09). ORR was 47.2% versus 41.8%, respectively. Among patients in the cisplatin-based versus carboplatin-based chemotherapy alone arms, 55.8% versus 41.8% received a subsequent anti–programmed cell death protein 1/ligand 1 therapy. The addition of pembrolizumab did not significantly increase the incidence of adverse events reported. ConclusionResults suggest trends towards OS and PFS improvements with the addition of pembrolizumab to gemcitabine-platinum doublet over gemcitabine-platinum alone regardless of whether cisplatin or carboplatin was the chosen platinum agent. OS may have been influenced by active subsequent therapies. MicroAbstractUntil recently, the standard first-line treatment for advanced urothelial carcinoma included platinum-based chemotherapy containing either cisplatin or carboplatin. This exploratory analysis from the KEYNOTE-361 study describes efficacy outcomes with the addition of pembrolizumab to cisplatin- or carboplatin-based chemotherapy to determine if there are differences in clinical benefit between patients who received cisplatin-based versus carboplatin-based combination therapy.

Efficacy and safety of pembrolizumab in patients with advanced urothelial carcinoma deemed potentially ineligible for platinum-containing chemotherapy: Post hoc analysis of KEYNOTE-052 and LEAP-011.

First-line pembrolizumab monotherapy is a standard of care for platinum-ineligible patients with advanced urothelial carcinoma (UC). No global standardized definition of platinum ineligibility exists. This study aimed to evaluate the efficacy and safety of pembrolizumab monotherapy in patients with UC who met various criteria for platinum ineligibility. Patients from KEYNOTE-052 and LEAP-011 deemed potentially platinum ineligible were pooled for this post hoc exploratory analysis as follows: group 1: Eastern Cooperative Oncology Group performance status (ECOG PS) 2; group 2: ECOG PS 2 and age ≥80 years, renal dysfunction, or visceral disease; and group 3: any two other factors regardless of ECOG PS. Patients received pembrolizumab 200 mg intravenously every 3 weeks. End points included objective response rate (ORR), progression-free survival (PFS) per Response Evaluation Criteria in Solid Tumors, version 1.1, by blinded independent central review, overall survival (OS), and safety. A total of 612 patients treated with pembrolizumab from KEYNOTE-052 (n=370) and LEAP-011 (n=242) were included; the median (range) follow-up was 56.3 months (51.2-65.3 months) and 12.8 months (0.2-25.1 months), respectively. For group 1, ORR was 26.2%, median PFS was 2.7 months, and median OS was 10.1 months. For group 2, ORR ranged from 23.5% to 33.3%, median PFS ranged from 2.1 to 4.4 months, and median OS ranged from 9.1 to 10.1 months. For group 3, ORR ranged from 25.7% to 27.9%, median PFS ranged from 2.1 to 2.8 months, and median OS ranged from 9.0 to 10.6 months. Treatment-related adverse event rates were consistent across groups. Frontline pembrolizumab has consistent antitumor activity and safety in patients with advanced UC categorized as potentially ineligible for platinum-based chemotherapy, regardless of the variable definitions of platinum ineligibility used.

Body composition derangements in lung cancer patients treated with first-line pembrolizumab: A multicentre observational study.

While immune checkpoint inhibitors (ICIs) are increasingly reshaping the therapeutic landscape of non-small-cell lung cancer (NSCLC), only a limited proportion of patients achieve a relevant and long-lasting benefit with these treatments, calling for the identification of clinical and, ideally modifiable, predictors of efficacy. Body composition phenotypes may reflect aspects of patients' immunology and thereby their ability to respond to ICIs. This study aims to explore the possible association between pre-treatment body composition phenotypes, tumour response, and clinical outcomes in patients receiving first-line pembrolizumab monotherapy for advanced NSCLC. A retrospective review of consecutive patients with treatment-naïve NSCLC and PD-L1 expression ≥50% undergoing pembrolizumab at three academic institutions was performed. Pre-treatment body composition parameters were measured at the third lumbar vertebra level by computed tomography, defined using pre-established cut-offs. Primary endpoint was objective response rate (ORR), secondary endpoints progression-free survival and overall survival (PFS and OS), compared through the log-rank test and the Cox proportional hazards model. Data from 134 patients (93 males [69.4%] and 41 females [30.6%]) were collected. Median age was 69years (range 36-85), with a median follow-up of 12months (range 1-131). The median body mass index (BMI) was 24.5 (IQR 21.5; 26.1) kg/m2. Overall, 59.0% and 51.5% of patients met established radiographic criteria for evidence of sarcopenia and myosteatosis, respectively, which occur across the BMI spectrum. Multivariate regression analysis, adjusted for co-morbidities, revealed that sarcopenia (aOR 5.56, 95% CI. 2.46-12.6, P<0.0001) and low intermuscular adipose tissue (IMAT) area (aOR 1.83, 95% CI. 1.22-2.83, P=0.001) were associated with a lower rate of ORR (30.4% vs. 70.5%, P<0.0001 and 30.7% vs. 73.2%, P<0.0001, respectively). Moreover, both in univariate and multivariate analysis, adjusted for co-morbidities, low performance status according to the Eastern Cooperative Oncology Group scale (ECOG PS), sarcopenia and low IMAT were significantly related to short PFS (ECOG PS: aHR 2.73, 95% CI 1.60-4.66, P<0.0001; sarcopenia: aHR 2.24, 95% CI 1.37-3.67, P=0.001; IMAT depot: aHR 2.26, 95% 1.40-3.63, P=0.002) and OS (ECOG PS: aHR 3.44, 95% CI 1.96-6.01, P<0.0001; sarcopenia: aHR 4.68, 95% CI 2.44-8.99, P<0.0001; IMAT depot: aHR 3.18, 95% 1.72-5.88, P<0.0001). Skeletal muscle abnormalities, apparently frequent in NSCLC, potentially represent intriguing predictive markers of response to ICIs and survival outcomes. Large prospective trials are needed to validate ICIs responders' clinical biomarkers.

First-line pembrolizumab with or without chemotherapy for recurrent or metastatic head and neck squamous cell carcinoma: 5-year follow-up of the Japanese population of KEYNOTE‑048.

Previously reported results from phase III KEYNOTE-048 demonstrated similar or improved overall survival (OS) with pembrolizumab or pembrolizumab-chemotherapy versus cetuximab-chemotherapy (EXTREME) in Japanese patients with recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC). We report results in Japanese patients from KEYNOTE-048 after 5years of follow-up. Patients with R/M HNSCC of the oropharynx, oral cavity, hypopharynx, or larynx were randomly assigned 1:1:1 to pembrolizumab, pembrolizumab-chemotherapy, or EXTREME. Primary endpoints were OS and progression-free survival. Efficacy was evaluated in the programmed cell death ligand 1 (PD-L1) combined positive score (CPS) ≥ 20, PD-L1 CPS ≥ 1, and total Japanese populations. In Japan, 67 patients were enrolled (pembrolizumab, n = 23; pembrolizumab-chemotherapy, n = 25; EXTREME, n = 19). Median follow-up was 71.0months (range, 61.2-81.5); data cutoff, February 21, 2022. 5-year OS rates with pembrolizumab versus EXTREME were 35.7% versus 12.5% (hazard ratio [HR] 0.38; 95% CI 0.13-1.05), 23.8% versus 12.5% (HR 0.70; 95% CI 0.34-1.45), and 30.4% versus 10.5% (HR 0.54; 95% CI 0.27-1.07) in the PD-L1 CPS ≥ 20, CPS ≥ 1, and total Japanese populations, respectively. 5-year OS rates with pembrolizumab-chemotherapy versus EXTREME were 20.0% versus 14.3% (HR 0.79; 95% CI 0.27-2.33), 10.5% versus 14.3% (HR 1.18; 95% CI 0.56-2.48), and 8.0% versus 12.5% (HR 1.11; 95% CI 0.57-2.16) in the PD-L1 CPS ≥ 20, CPS ≥ 1, and total Japanese populations, respectively. After 5years of follow-up, pembrolizumab and pembrolizumab-chemotherapy showed long-term clinical benefits; results further support these treatments as first-line options for Japanese patients with R/M HNSCC. NCT02358031.

Prognostic Value of KRAS/TP53 Status for Overall Survival in First-Line Monoimmunotherapy and Chemoimmunotherapy Treated Patients With Nonsquamous NSCLC in the Netherlands: A Brief Report

IntroductionProgrammed death-ligand 1 (PD-L1) is the main predictive biomarker used to identify patients with NSCLC who are eligible for treatment with immune checkpoint inhibitors. Despite its utility, the predictive capacity of PD-L1 is limited, necessitating the exploration of supplementary predictive biomarkers. In this report, we describe the prognostic value of KRAS/TP53 mutation status for overall survival (OS) in patients with NSCLC treated with first-line immunotherapy or combined chemoimmunotherapy. MethodsClinical data of all patients diagnosed with metastatic nonsquamous NSCLC in the Netherlands between January 1 and December 31 of 2019 were retrieved from the Netherlands Cancer Registry and linked to pathology reports of the Dutch Nationwide Pathology Databank. A total of 694 patients with available KRAS and TP53 mutation status and treated with first-line pembrolizumab or chemoimmunotherapy were included, with a median follow-up time of 42.5 months. Patients with an EGFR or MET mutation or ALK, ROS1, or RET fusion were excluded from the analysis. ResultsAmong patients treated with first-line pembrolizumab or chemoimmunotherapy, mutations in KRAS and TP53 occurred in 48.8% (n = 339) and 58.4% (n = 405), respectively. OS differed significantly between KRAS/TP53 mutational subgroups in patients treated with first-line pembrolizumab or chemoimmunotherapy (log-rank test, p = 0.007). Median OS of pembrolizumab or chemoimmunotherapy treated patients with mutated TP53 was longer in patients with KRAS-wildtype (485 versus 359 d, hazard ratio [HR] = 0.76, p = 0.028) or mutated KRAS (571 versus 447 d, HR = 0.73, p = 0.019). In a separate analysis of treatment subgroups, mutated TP53 was associated with longer median OS in chemoimmunotherapy treated KRAS-wildtype patients (468 versus 341 d, HR = 0.71, p = 0.029) but not in monoimmunotherapy treated patients with KRAS-wildtype (512 versus 371 d, HR = 0.91, p = 0.78). In multivariable Cox regression analysis including age, sex, clinical disease stage, and PD-L1 tumor proportion score, KRAS/TP53 mutation status was no longer associated with OS. ConclusionsAmong patients with metastatic NSCLC who are treated with pembrolizumab or chemoimmunotherapy, the presence of a pathogenic TP53 and KRAS mutation is associated with longer OS. Nevertheless, in multivariable Cox regression analysis including age, sex, clinical disease stage, and PD-L1 tumor proportion score, KRAS/TP53 mutation status was no longer associated with OS.

Outcomes by Retrospective Eligibility for Maintenance Therapy of Patients With Advanced Urothelial Carcinoma: Posthoc Analysis of the Phase 3 KEYNOTE-361 Trial

IntroductionThe phase 3 KEYNOTE-361 trial of first-line pembrolizumab with or without chemotherapy versus chemotherapy alone in patients with locally advanced or metastatic urothelial carcinoma (la/mUC) completed enrollment before the approval of postchemotherapy maintenance avelumab for patients without progressive disease. This post hoc analysis evaluated the outcomes of patients who received chemotherapy alone in KEYNOTE-361 by retrospective eligibility for subsequent maintenance therapy. Patients and MethodsPatients in the chemotherapy alone arm were retrospectively categorized as maintenance eligible (received ≥4 cycles of chemotherapy and did not die or experience disease progression within 10 weeks of chemotherapy completion), maintenance ineligible (received <4 cycles of chemotherapy or had progressive disease or died within 0-10 weeks after completion of ≥4 cycles of chemotherapy), and indeterminate eligibility for maintenance therapy (if neither maintenance eligible or ineligible). End points included progression-free survival per Response Evaluation Criteria in Solid Tumors version 1.1 by blinded independent central review and overall survival from randomization (start of chemotherapy). ResultsMedian follow-up was 31.7 months (range, 22.0-42.3). Among 342 patients who received chemotherapy alone, 172 (50.3%) were maintenance eligible, 108 (31.6%) were maintenance ineligible, and 62 (18.1%) had indeterminate eligibility for maintenance therapy. The median progression-free survival was 9.0 months (95% CI 8.4-10.4) in maintenance-eligible patients, 5.1 months (4.2-6.0) in maintenance-ineligible patients, and 2.3 months (1.9-3.8) in the indeterminate group; median overall survival was 23.3 months (95% CI 19.4-26.1), 10.2 months (9.1-11.6), and 5.5 months (3.7-8.5), respectively. ConclusionThis post hoc analysis suggests that a majority of patients with untreated la/mUC who initiated chemotherapy in a clinical trial may have been considered eligible for maintenance therapy and had favorable survival outcomes compared with those considered maintenance ineligible.

Pembrolizumab With or Without Maintenance Olaparib for Metastatic Squamous Non-SCLC That Responded to First-Line Pembrolizumab Plus Chemotherapy

IntroductionPoly (adenosine diphosphate-ribose) polymerase inhibitors can up-regulate programmed death-ligand 1 expression and promote immune-mediated responses and may improve efficacy of first-line anti‒programmed cell death protein 1‒based therapies in patients with metastatic squamous NSCLC. MethodsIn this randomized, double-blind, phase 3 trial (NCT03976362), adults with previously untreated stage IV squamous NSCLC received 4 cycles of induction therapy (pembrolizumab 200 mg every 3 weeks plus carboplatin and paclitaxel or nab-paclitaxel). Patients with disease control were randomized to 31 cycles of pembrolizumab 200 mg every 3 weeks plus olaparib 300 mg orally twice daily or placebo. Dual primary end points were progression-free survival (PFS) and overall survival (OS). PFS was tested at interim analysis 2 (the final PFS analysis); OS was tested at final analysis. ResultsA total of 851 patients received induction treatment; 296 were randomized to pembrolizumab plus olaparib and 295 to pembrolizumab plus placebo. At interim analysis 2, with median follow-up of 27.1 months, median (95% confidence interval [CI]) PFS was 8.3 (6.7‒9.7) months in the pembrolizumab plus olaparib group and 5.4 (4.1‒5.6) months in the pembrolizumab plus placebo group (hazard ratio = 0.77, 95% CI: 0.63‒0.93, p = 0.0040 [not significant at a one sided at superiority boundary of p = 0.003]). At final analysis, with median follow-up of 33.4 months, median (95% CI) OS was 19.1 (15.9‒22.2) and 18.6 (16.0‒21.6) months, respectively (hazard ratio = 1.01, 95% CI: 0.83‒1.24, p = 0.5481). Treatment-related adverse events occurred in 76.5% and 65.1% of patients, respectively. ConclusionsAdding olaparib to pembrolizumab as maintenance therapy for metastatic squamous NSCLC did not significantly improve PFS versus pembrolizumab plus placebo, neither PFS nor OS met the prespecified statistical significance boundary. No new safety signals were identified. Trial registrationClinicalTrials.gov, NCT03976362.

Calibrating Observational Health Record Data Against a Randomized Trial

The conditions required for health record data sources to accurately assess treatment effectiveness remain unclear. Emulation of randomized clinical trials (RCTs) with health record data and subsequent calibration of the results can help elucidate this. To pilot an emulation of the KEYNOTE-189 RCT using a commercially available electronic health record (EHR) data source. This retrospective cohort study used an EHR database spanning from April 2007 to February 2023. Follow-up began on treatment initiation and proceeded until an outcome event, loss to follow-up, end of data, or end of study period (640 days). The population-based cohort was ascertained from EHRs provided by 52 health systems across the US. Eligibility criteria were defined as closely as possible to the benchmark RCT. Patients with non-small cell lung cancer initiating first-line treatment for metastatic disease were included. Patients with evidence of squamous non-small cell lung cancer, primary nonlung malignant neoplasms, or identified EGFR/ALK variations were excluded. Data were analyzed from June to October 2023. Initiation of first-line pembrolizumab and chemotherapy and chemotherapy alone. Chemotherapy in both groups was defined as a combination of pemetrexed and platinum-based (carboplatin or cisplatin) therapy. Outcomes of interest were 12-month survival probability and mortality hazard ratio (HR). A total of 1854 patients (mean [SD] age, 63.7 [9.6] years; 971 [52.4%] men) were eligible, including 589 patients who initiated pembrolizumab and chemotherapy and 1265 patients who initiated chemotherapy only. The cohort included 364 Black patients (19.6%) and 1445 White patients (77.9%). The 12-month survival probabilities were 0.60 (95% CI, 0.54-0.65) in the pembrolizumab group and 0.58 (95% CI, 0.55-0.62) in the chemotherapy-only group, compared with 0.69 (95% CI, 0.64-0.74) in the KEYNOTE-189 pembrolizumab group and 0.49 (95% CI, 0.42-0.56) in the KEYNOTE-189 chemotherapy-only group. The mortality HR was 0.95 (95% CI, 0.78-1.16), compared with 0.49 (95% CI, 0.38-0.64) in the KEYNOTE-189 RCT. In this cohort study piloting an RCT emulation, results were incongruous with the benchmark trial. Differences in patient treatment and data capture between the RCT and EHR populations, confounding by indication, treatment crossover, and accuracy of captured diagnoses may explain these findings. Future feasibility assessments will require data sources to have important oncology-specific measures curated.

HLA-A01 and HLA-B27 Supertypes, but Not HLA Homozygocity, Correlate with Clinical Outcome among Patients with Non-Small Cell Lung Cancer Treated with Pembrolizumab in Combination with Chemotherapy.

Maximal heterozygosity on the human leukocyte antigen (HLA) loci has been found to be associated with improved survival and development of immune-related adverse events (irAEs) among NSCLC patients treated with immunotherapy. Here, we investigated the effect of germline HLA-I/-II on clinical outcomes among NSCLC patients treated with first-line pembrolizumab in combination with chemotherapy. We prospectively recruited patients with NSCLC who were commencing first-line pembrolizumab in combination with chemotherapy. DNA from white blood cells was used for high-resolution HLA-I/II typing. Of the 65 patients recruited, 53 complied with the inclusion criteria. We did not find an association between HLA-I/-II homozygosity and clinical outcome among the studied population. However, the presence of HLA-A01 was associated with unfavourable PFS (HR = 2.32, 95%CI 1.13-4.77, p = 0.022) and worsening OS (HR = 2.86, 95%CI 1.06-7.70, p = 0.038). The presence of HLA-B27 was associated with improved PFS (HR = 0.35, 95%CI 0.18-0.71, p = 0.004) and trends toward improving OS. None of the HLA-I supertypes were associated with the development or worsening of irAEs. The absence of association between genomic HLA-I/-II homozygosity and clinical outcome among patients with advanced NSCLC treated with pembrolizumab in combination with chemotherapy might reflect a diminished role for HLA molecules among patients with low or no PD-L1. HLA-A01 and HLA-B27 might have a role in predicting clinical outcomes among this cohort of patients. Further studies are needed to explore biomarkers for this group of patients.

1319P Impact of concomitant co-medications on survival with first-line pembrolizumab in 43,000 French patients with advanced NSCLC

1319P Impact of concomitant co-medications on survival with first-line pembrolizumab in 43,000 French patients with advanced NSCLC

1394TiP KRYSTAL-7: A phase III study of first-line adagrasib plus pembrolizumab versus pembrolizumab alone in patients with advanced NSCLC with KRASG12C mutation

1394TiP KRYSTAL-7: A phase III study of first-line adagrasib plus pembrolizumab versus pembrolizumab alone in patients with advanced NSCLC with KRASG12C mutation

47P First-line pembrolizumab (pembro) + gemcitabine and cisplatin (gem/cis) for advanced biliary tract cancer (BTC) in the China subpopulation from the phase III KEYNOTE-966 study

47P First-line pembrolizumab (pembro) + gemcitabine and cisplatin (gem/cis) for advanced biliary tract cancer (BTC) in the China subpopulation from the phase III KEYNOTE-966 study

Pembrolizumab Plus Carboplatin and Paclitaxel as First-Line Therapy for Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma (KEYNOTE-B10): A Single-Arm Phase IV Trial.

Standard-of-care first-line treatment for recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC) is pembrolizumab plus platinum and fluorouracil (FU). However, FU is associated with potential challenges (continuous 4-day infusion, high administration costs, and cardiovascular and gastrointestinal toxicities), creating a clinical need for alternative chemotherapy combinations. We evaluated the efficacy and safety of first-line pembrolizumab plus carboplatin and paclitaxel for R/M HNSCC in the open-label, single-arm, phase IV KEYNOTE-B10 study (ClinicalTrials.gov identifier: NCT04489888). Eligible adults had previously untreated, histologically or cytologically confirmed R/M HNSCC regardless of PD-L1 status, measurable disease per RECIST v1.1 by blinded independent central review (BICR), and an Eastern Cooperative Oncology Group performance status of 0 or 1. Patients received pembrolizumab 200 mg intravenously once every 3 weeks for ≤35 cycles and carboplatin AUC 5 mg/mL/min intravenously once every 3 weeks for ≤6 cycles and investigator's choice of paclitaxel 100 mg/m2 on days 1 and 8 or 175 mg/m2 on day 1, intravenously once every 3 weeks. The primary end point was objective response rate per RECIST v1.1 by BICR. Between October 27, 2020, and April 29, 2022, 149 patients were screened and 101 received treatment. As of February 20, 2023, the median follow-up was 18.9 months (range, 9.1-27.0). At this final analysis, 49 (49%) of 101 patients had an objective response (95% CI, 38.4 to 58.7), including seven patients (7%) with a confirmed complete response. Of the 101 treated patients, grade 3-5 and serious treatment-related adverse events occurred in 76 (75%) and 27 (27%), respectively. There were no new safety signals. Pembrolizumab plus carboplatin and paclitaxel showed promising antitumor activity and a manageable safety profile in first-line R/M HNSCC, suggesting this combination may be an alternative option for this patient population.

Cost-effectiveness analysis of pembrolizumab plus chemotherapy versus placebo plus chemotherapy for HER2-negative advanced gastric/gastroesophageal junction cancer in the Chinese healthcare system

ABSTRACT Background This study compares first-line pembrolizumab plus chemotherapy with chemotherapy alone for patients with HER2-negative advanced gastric cancer (GC) and gastroesophageal junction cancer (GEJC) in China. Methods A Markov state-transition model was developed based on the phase 3 randomized KEYNOTE-859 clinical trial data. The health state utility values and direct medical costs were derived from the KEYNOTE-859 clinical trial, the relevant literature, and local charges. The measured outcomes included quality-adjusted life-years (QALYs) and the incremental cost-effectiveness ratio (ICER). Probabilistic and one-way sensitivity analyses (OWSA) were performed to assess the uncertainty of the model. Results In the base analysis, the incremental effectiveness and cost of pembrolizumab plus chemotherapy versus chemotherapy alone were 0.22 QALYs and $16,627.31, respectively, resulting in an ICER of $76,936.60/QALY, which is higher than the willingness-to-pay threshold in China ($35,864.61/QALY). Subgroup analyses revealed that the ICERs of pembrolizumab plus chemotherapy versus chemotherapy alone were $72,762.68 and $34,813.70 in the populations with PD-L1 CPS of 1 or higher (CPS ≥ 1) and PD-L1 CPS ≥ 10 (CPS ≥ 10), respectively. Conclusions As first-line therapy for patients with locally advanced or metastatic HER2-negative GC/GEJC in China, pembrolizumab plus chemotherapy is less cost-effective than chemotherapy alone, however, in the CPS ≥ 10 subgroup is more.

PP01.53 Patient-Reported Outcomes (PROs) in Metastatic Non-Squamous Non-Small Cell Lung Cancer (NSCLC): PERLA Trial Comparing First-Line Chemotherapy Plus Dostarlimab or Pembrolizumab

PP01.53 Patient-Reported Outcomes (PROs) in Metastatic Non-Squamous Non-Small Cell Lung Cancer (NSCLC): PERLA Trial Comparing First-Line Chemotherapy Plus Dostarlimab or Pembrolizumab

Health Care Resource Use for Modern First-Line Treatments in Metastatic Renal Cell Carcinoma

Immuno-oncology agents have changed the treatment paradigm for metastatic renal cell carcinoma (mRCC). Such therapies improve survival but can impose considerable health care resource use (HCRU) and associated costs, necessitating their examination. To compare HCRU, costs, and clinical outcomes among patients receiving first-line pembrolizumab plus axitinib (P+A) or ipilimumab plus nivolumab (I+N). This retrospective cohort study used data from an administrative claims database on patients with mRCC receiving first-line P+A or I+N that was initiated between January 2018 and May 2020. Data were analyzed from February 2021 to July 2022. First-line P+A or I+N. HCRU and costs during the first 90 days, full first-line treatment, and full follow-up periods were assessed. Using Kaplan-Meier analysis, time on treatment, overall survival, time to first emergency department (ED) visit, and time to first inpatient stay were compared. Among 507 patients, there were 126 patients receiving P+A (91 male [72.2%]; mean [SD] age, 67.93 [9.66] y) and 381 patients receiving I+N (271 male [71.1%]; mean [SD] age, 66.52 [9.94] years). The median time on treatment was longer for the P+A compared with I+N group (12.4 months [95% CI, 8.40 months to not estimable] vs 4.1 months [95% CI, 3.07 to 5.30 months]; P < .001). The median time to first ED visit was longer for the P+A than I+N group (7.2 months [95% CI 3.9 to 11.1 months ] vs 3.3 months [95% CI, 2.6 to 3.9 months]; P = .005), as was time to first inpatient stay (9.0 months [95% CI 6.5 months to not estimable] vs 5.6 months [95% CI, 3.9 to 7.9 months]; P = .02). During the first 90 days, a lower proportion of the P+A than N+I group had ED visits (43 patients [34.1%] vs 182 patients [47.8%] and inpatient stays (24 patients [19.1%) vs144 patients [37.8%]; P < .001). During full follow-up, mean total adjusted costs were similar for P+A and I+N groups, but adjusted 12-month estimated total costs were higher for P+A than I+N groups ($325 574 vs $ 263 803; P = .03). In this study, treatment with P+A was associated with longer time on treatment, time to first ED visit, and inpatient stay, while 12-month estimated costs were higher for the P+A group. This is among the first clinical studies to evaluate economic burden associated with modern treatments for mRCC.

SA11 Real-World Effectiveness and Safety of First-Line Pembrolizumab Monotherapy for Patients With Advanced or Metastatic Non-Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

SA11 Real-World Effectiveness and Safety of First-Line Pembrolizumab Monotherapy for Patients With Advanced or Metastatic Non-Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

Exploration of different immunogenomic TMEs in gastric cancer based on HER2 and PD-L1 expression.

e16073 Background: Recent results from the KEYNOTE-811 study showed that first-line pembrolizumab was superior to placebo with respect to progression-free survival (PFS) in combination with trastuzumab and chemotherapy in patients with HER2 positive metastatic gastric cancer (GC). Interestingly, In the subgroup analysis, the PFS benefit with pembrolizumab was significant in patients with tumors with PD-L1 CPS ≥1, whereas there was no benefit in the small subgroup of patients with tumors with CPS &lt; 1. Therefore, this study is to investigate immune-genomic differences in the tumor microenvironment according to the composition of surrounding cells and the expression status of HER2 and PD-L1. Methods: Utilizing single cell RNA sequencing (scRNA seq) and TCR sequencing, we examined 14 HER2 positive and 18 negative primary GC samples with CPS score based on PD-L1 IHC 22C3 pharmDx. Among the HER2-positive group, there were 4 samples in the CPS &lt; 1 (negative) and 10 samples in the CPS ≥1 (positive) group. In the HER2 negative group, there were 6 samples in the CPS &lt; 1 and 12 samples in the CPS ≥1. Results: First, when analyzing the distribution of total cells according to HER2 status, in the HER2 positive group, more endothelial cells ( p= 0.034) and fibroblasts ( p= 0.054) appeared in the PD-L1 negative group compared to the PD-L1 positive group, while there was no difference in the HER2 negative group. Furthermore, Through TCR analysis, the exhausted and cytotoxic score exhibit contrasting trends between HER2 negative and positive groups. In HER2-positive patients, the exhausted and cytotoxic score appear significantly higher in the CPS negative group. Next, we evaluated the proportion of immune cells according to HER2 status. The observed of CD4 Treg ( p= 0.084) and CD8 exhausted T (Tex), ( p= 0.036) cells was increased in the HER2 positive compared to the negative. When regrouped according to PD-L1 expression, only the HER2 positive group showed a tendency to increase the observation of CD4 Treg and CD8 Tex cells compared to positive in PD-L1 negative. In addition, we investigated whether the expression pattern of other immune checkpoint molecules differed depending on the PD-L1 expression pattern in both HER2 positive and negative patients. In the HER2 negative group, the expression of immune checkpoint proteins was similar regardless of the CPS expression group, or the expression of some proteins was higher in the CPS positive group. In other hands, in HER2 positive, CPS &lt; 1 group had higher expression of immune checkpoint proteins, such as PDCD1, LAG2, BTLA, VISTA and TIGHT. Conclusions: The high proportion of CD4 Tregs, CD8 Tex and the elevated exhausted score in the subgroup with CPS &lt; 1 in HER2 positive GCs suggesting immune exclusive environment compared to her-2 and PD-L1 coexpressing group. Considering increased expression of immune checkpoint proteins other than PD-1/PD-L1, for patients with HER2-positive and CPS &lt; 1, combination therapy with other immune checkpoint inhibitors rather than anti-PD-1/PD-L1 may be suggested.