Pembrolizumab Monotherapy Research Articles

Evolving Precision First-Line Systemic Treatment for Patients with Unresectable Non-Small Cell Lung Cancer.

First-line systemic therapy for patients with advanced or metastatic non-small cell lung cancer (NSCLC) has rapidly evolved over the past two decades. First, molecularly targeted therapy for a growing number of gain-of-function molecular targets has been shown to improve progression-free survival (PFS) and overall survival (OS) with favorable toxicity profiles compared to platinum-containing chemotherapy and can be given as first-line systemic therapy in ~25% of patients with NSCLC. Actionable genetic alterations include EGFR, BRAF V600E, and MET exon 14 splicing site-sensitizing mutations, as well as ALK-, ROS1-, RET-, and NTRK-gene fusions. Secondly, inhibitors of programmed cell death protein 1 or its ligand 1 (PD-1/L1) such as pembrolizumab, atezolizumab, or cemiplimab monotherapy have become a standard of care for ~25% of patients with NSCLC whose tumors have high PD-L1 expression (total proportion score (TPS) ≥50%) and no sensitizing EGFR/ALK alterations. Lastly, for the remaining ~50% of patients who are fit and whose tumors have no or low PD-L1 expression (TPS of 0-49%) and no sensitizing EGFR/ALK aberrations, platinum-containing chemotherapy with the addition of a PD-1/L1 inhibitor alone or in combination of a cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitor improves PFS and OS compared to chemotherapy alone. The objectives of this review are to summarize the current data and perspectives on first-line systemic treatment in patients with unresectable NSCLC and propose a practical algorithm for implementing precision biomarker testing at diagnosis.

Phase II trial of pembrolizumab, ipilimumab, and aspirin in melanoma: clinical outcomes and translational predictors of response

ObjectiveMany patients with melanoma treated with immune checkpoint inhibitors (ICIs) do not derive response. Preclinical and retrospective studies identified that inhibition of the cyclooxygenase (COX) pathway may improve response to ICI treatment.MethodsThis prospective single site phase II trial accrued patients with advanced/metastatic melanoma. Participants underwent high-dose aspirin daily combined with pembrolizumab and ipilimumab every 3 weeks for 4 cycles followed by high-dose aspirin and pembrolizumab monotherapy. The primary endpoint was objective response rate (ORR). Longitudinal sampling of blood was performed to assess peripheral immune correlates.ResultsTwenty-seven subjects were enrolled with median follow-up of 32 months. An ORR of 62.9% was reached prior to discontinuation due to low likelihood of achieving the pre-specified ORR of 80%. 17 patients (63%) experienced a treatment-related adverse event (TRAEs) grade 3 or higher. A per-protocol analysis showed that patients able to continue aspirin alongside ICI through the induction period experienced significant survival benefit. Ten cytokines and increased regulatory T cells in the periphery correlated with beneficial response.ConclusionsThe addition of high-dose aspirin to combination ICI within this study results in response comparable to ICI alone. Future clinical studies of COX inhibition will need to focus on mitigation of AEs to establish the clinical utility of this combination.

Assessing the fiscal consequences of novel and existing treatments for triple negative breast cancer in Switzerland by applying a government perspective framework

Background Triple Negative Breast Cancer (TNBC) is an aggressive subtype of breast cancer that can impact patients’ employment and workforce participation. This study estimates how the employment effects of TNBC impact government tax revenue and public benefits expenditure in Switzerland, representing the fiscal burden of disease (FBoD), and likely consequences of introducing new treatment options. Methods A four-state cohort model was used to calculate fiscal effects for two treatments: Neoadjuvant pembrolizumab plus chemotherapy followed by adjuvant pembrolizumab monotherapy (P + C→P) and neoadjuvant chemotherapy alone (C). Lifetime present values of tax revenue, social benefit payments, and healthcare costs were calculated for the average population and those undergoing treatment to assess the FBoD. Results An average TNBC patient treated with C and P + C→P is expected to generate CHF128,999 and CHF97,008 less tax than the average population, respectively, and require increased social benefit payments. Compared to C, 75% of the incremental healthcare costs of P + C→P are estimated to be offset through tax revenue gains. Conclusions This analysis demonstrates that 75% of the additional costs of a new TNBC treatment option can be offset by gains in tax revenue. Fiscal analysis can be a useful tool to complement existing methods for evaluating new treatments.

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

The evolving role of immune checkpoint inhibitors in cervical and endometrial cancer.

The introduction of immune checkpoint inhibitors (ICIs) has revolutionized the treatment landscape for numerous tumor types, including cervical and endometrial cancers. Multiple ICIs against programmed cell death-1 (PD-1), programmed death-ligand 1 (PD-L1), and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) have demonstrated encouraging outcomes in controlled clinical studies for advanced cervical and endometrial cancers. For advanced cervical cancer, approved ICIs as second-line treatment include cemiplimab, nivolumab, and pembrolizumab as single agents. In the first-line treatment setting, options include pembrolizumab alone or in combination with bevacizumab, as well as atezolizumab combined with a backbone platinum-based chemotherapy plus bevacizumab. Additionally, for locally advanced cervical cancer, pembrolizumab is recommended alongside concurrent chemoradiotherapy. For endometrial cancer, pembrolizumab monotherapy, pembrolizumab in combination with lenvatinib, and dostarlimab are currently approved as second-line treatment options. Moreover, either dostarlimab or pembrolizumab can be added to first-line platinum-based chemotherapy for mismatch repair deficient malignancies. Although the inclusion of these agents in clinical practice has led to improved overall response rates and survival outcomes, many patients still lack benefits, possibly due to multiple intrinsic and adaptive resistance mechanisms to immunotherapy. This review aims to highlight the rationale for utilizing ICIs and their current role, while also delineating the proposed mechanisms of resistance to ICIs in cervical and endometrial cancer.

A phase 2 study to evaluate efficacy and safety of PRGN-2009, a novel gorilla adenovirus-based immunotherapy, in combination with pembrolizumab versus pembrolizumab monotherapy in patients with recurrent or metastatic cervical cancer.

TPS5623 Background: The association between cervical cancer and human papillomavirus (HPV) is well understood, with nearly all cervical cancer known to be caused by high risk HPV infection. HPV16 and HPV18 are the most common high-risk HPV types and are responsible for about 70% of cervical cancer cases. Recurrent or metastatic cervical cancer is currently treated with pembrolizumab alone or in combination with chemotherapy, however t there remains a significant need for treatments for patients that recur or do not respond at all to pembrolizumab treatment. PRGN-2009 is a gorilla adenovirus-based immunotherapy targeting cancers caused by HPV16 or HPV18. PRGN-2009 includes a novel HPV antigen design to induce HPV16/18-specific T cell immune responses against cancer cells. The rationale for combining the PRGN-2009 with immune checkpoint inhibitor is based on preclinical and clinical data demonstrating that combination of cancer vaccines and immune checkpoint inhibitors can trigger intensified immunogenicity leading to increased antitumor efficacy compared to either treatment alone. PRGN-2009 has been characterized in both in vitroand in vivostudies to support the scientific rationale and the safety of PRGN-2009 has been demonstrated in evaluated in initial Phase 1/2 studies in patients with HPV+ malignancies. Methods: This is a randomized, Phase 2 study to evaluate efficacy and safety of PRGN-2009 in combination with pembrolizumab compared to pembrolizumab alone in patients with recurrent or metastatic cervical cancer. Key inclusion criteria include recurrent or metastatic cervical cancer (histologically or cytologically confirmed) resistant to pembrolizumab. Subjects will be randomized 1:1 to Cohort 1: Combination of PRGN-2009, 5 x 1011 PU (Day 0, Day 21 and Day 42, then q6w), plus pembrolizumab, 400mg q6w, or to Cohort 2: pembrolizumab alone (400 mg q6w). Subjects randomized to Cohort 2 (pembrolizumab monotherapy) and who have confirmed disease progression (per RECIST 1.1) after at least one cycle of pembrolizumab and have had no Grade ≥ 3 adverse events related to treatment will be offered the option to crossover to Cohort 1 (PRGN-2009 plus pembrolizumab). All subjects will be evaluated for safety and efficacy of PRGN-2009 in combination with pembrolizumab, and for biological correlative assays. The primary endpoint is objective response rate (ORR) following treatment with PRGN-2009 in combination with pembrolizumab or pembrolizumab monotherapy, and will be tested using Fleming’s two-stage design and the stopping boundaries for futility and efficacy applied. The study is currently recruiting patients with recurrent or metastatic cervical cancer (NCT06157151). Clinical trial information: NCT06157151 .

STELLAR-305: A randomized phase 2/3 study of zanzalintinib plus pembrolizumab versus pembrolizumab alone in patients with previously untreated PD-L1 positive recurrent/metastatic head and neck squamous cell carcinoma.

TPS6114 Background: VEGFR, MET, and the TAM kinase AXL are overexpressed in recurrent/metastatic (R/M) head and neck squamous cell carcinoma (HNSCC); their activation contributes to increased tumor aggressiveness and poor prognosis. The immune checkpoint inhibitor (ICI) pembrolizumab, as monotherapy or in combination with chemotherapy, is a standard of care in patients with PD-L1 expressing R/M HNSCC. However, the response rate and survival benefit with pembrolizumab monotherapy are unsatisfactory, and addition of chemotherapy results in unfavorable toxicity. Zanzalintinib is a novel, multi-targeted tyrosine kinase inhibitor (TKI) of VEGFR, MET, and the TAM kinases (TYRO3, AXL, MER). Preclinical data suggest zanzalintinib-mediated inhibition of these kinases may suppress tumor growth and angiogenesis, while simultaneously promoting an immune-permissive tumor microenvironment that may enhance response to ICIs. Zanzalintinib + ICI combination has shown promising antitumor activity and manageable safety in a phase 1 study in solid tumors. To further support the TKI-ICI combination, phase 2 clinical activity was observed in R/M HNSCC with the multi-targeted TKI cabozantinib (inhibits VEGFR, MET, and TAM kinases) in combination with pembrolizumab. The present study, STELLAR-305, will evaluate the efficacy and safety of zanzalintinib + pembrolizumab vs pembrolizumab alone in previously untreated, PD-L1-positive, R/M HNSCC. Methods: STELLAR-305 (NCT06082167) is a randomized, double-blind, phase 2/3 study. Eligible patients are adults (≥18 years) with histologically or cytologically confirmed R/M HNSCC that is incurable with local therapy. Patients may not have been treated with systemic therapy, unless given as part of multimodal treatment for locally advanced disease and completed >6 months before randomization. Patients must have a primary tumor location of the oropharynx (HPV testing required), oral cavity, hypopharynx, or larynx; those with nasopharynx, salivary gland, or occult primary sites are excluded. Other eligibility criteria include a PD-L1 CPS ≥1, measurable disease per RECIST v1.1, and an ECOG performance status of 0–1. Patients with prior treatment with ICIs or zanzalintinib are not eligible. Patients will be randomized 1:1 to zanzalintinib + pembrolizumab, or placebo + pembrolizumab. The dual primary endpoints are PFS per RECIST v1.1 by blinded independent radiology committee and overall survival. Secondary endpoints include safety, PFS per RECIST v1.1 by investigator, objective response rate, and duration of response. If minimum efficacy requirements are met in phase 2, the study will proceed to phase 3 with approximately 500 patients enrolled across both phases. STELLAR-305 is currently enrolling, with 200 sites estimated for global expansion. Clinical trial information: NCT06082167 .

Lymphocyte activation markers predict the therapeutic response to immune checkpoint inhibitors: A case–control study

AbstractBackgroundReports on changes in circulating immune cells induced by immune checkpoint inhibitors (ICIs) and their association with therapeutic responses are limited. This study aimed to analyze the interaction between ICIs and circulating blood cells in real‐world practice and identify biomarkers associated with therapeutic efficacy.Materials and MethodsPatients with non‐small cell lung cancer who received nivolumab, pembrolizumab, or atezolizumab monotherapy were eligible. Blood samples were collected before and 7–21, and 22–42 days after treatment, and changes in the number and characteristics of neutrophils and lymphocytes in the peripheral blood were analyzed. The efficacy of ICIs was evaluated based on the best overall response up to 3 months after treatment. The patients were divided into the following groups: patients with non‐progressive disease (non‐PD) and those with progressive disease (PD). Blood immunological factors related to treatment response were analyzed.ResultsThere were 16 and 27 patients in the non‐PD and PD groups, respectively. The non‐PD group had significantly lower pretreatment CD56+ cell (CD56+ IFN‐γ+ cell), and neutrophil counts at 7–21 days after ICI administration than the PD group. Additionally, there was a significant increase in CD8+ IFN‐γ+, and CD8+CD28+ IFN‐γ+ T‐cell counts 7–21 days after ICI administration in the non‐PD group. CD8+CD28+IFN‐γ+ T‐cell count greater than 94.6 cells/μL at 7–21 days after ICI administration was highly predictive with an AUC greater than 0.8 in the ROC curve analysis.ConclusionsPredictors of disease progression include a low activated CD56+ cell count, no increase in the neutrophil count before ICI therapy, and an increase of activated CD8+ cell count early after ICI administration. The findings will contribute to selecting patients with a favorable therapeutic response and early prediction of therapeutic response to ICI.

Different dosing strategies of pembrolizumab in the treatment of NSCLC: A real-world retrospective observational study.

e23264 Background: Immune checkpoint inhibitors lack a dose-response relationship, allowing optimisation of dosing strategies that may reduce drug use. Pembrolizumab received its initial regulatory approval for the treatment of non-small cell lung cancer (NSCLC) at weight-based dosing (2 mg/kg every 3 weeks (Q3W)), as employed in pivotal clinical trials demonstrating its efficacy and safety. This dosing regimen was later replaced by the currently approved flat-dosing (200 mg Q3W or 400 mg Q6W) in all indications, potentially increasing drug use. This retrospective observational study evaluates differences in pembrolizumab use for different dosing strategies in a real-world patient cohort. Methods: Overall, 124 advanced NSCLC patients, treated with first-line pembrolizumab monotherapy at a single institution, were included. During the observation period, pembrolizumab flat-dosing was employed, with possible extensions of treatment administrations. Patient and treatment data were obtained from medical records. Duration of treatment was calculated from day 1 of first cycle to last day of last cycle, excluding treatment delays due to adverse events. Pembrolizumab use was calculated for 3 dosing strategies: i) as actually received, ii) as flat-dosing, iii) as body-weight dosing, capped at 200 mg Q3W. It is presented as median dose Q3W and cummulative dose in the whole cohort. Results: Included patients had a median weight of 73 kg (IQR: 65-84) and received a total of 1600 mg of pembrolizumab (IQR: 800-3600) over 24 weeks (IQR: 12-60). The median pembrolizumab dose was i) 190 mg Q3W (IQR: 172-200) as actually received by patients, and would be ii) 200 mg Q3W (IQR: 200-200) in case of flat dosing, and iii) 146 mg Q3W (IQR: 130-168) in case of body-weight dosing. Overall, total pembrolizumab dose in the whole cohort was i) 283,600 mg actually used, and would be ii) 327,800 mg in flat-dosing, and iii) 251,200 mg body-weight dosing, resulting in a 23.4% reduction of drug use in weight-adjusted vs flat-based dosing. Conclusions: Pembrolizumab dosing adjusted to body weight, as initially approved, would reduce drug use vs the currently approved flat-dosing, reaching nearly a 25% reduction in our cohort of patients.

A phase 2 study of ipatasertib in combination with pembrolizumab for first-line treatment of recurrent or metastatic squamous cell cancer of the head and neck.

TPS6117 Background: Single agent pembrolizumab in relapsed / metastatic head and neck squamous cell carcinoma (R/M HNSCC) has an estimated ORR of 19% and median OS of 13.6 months. There are several factors which may influence which patients respond to antibodies targeting the PD-1 axis. Regulatory T cells (Tregs) play a significant role in an immunosuppressive tumor microenvironment. Anti-PD-1 antibodies induce Treg activation in part through AKT pathway activation, which may contribute to low response rates to checkpoint inhibitor therapy. AKT blockade selectively inhibits the proliferation of human Tregs. Additionally, inhibition of the PI3K-AKT-mTOR pathway limits myeloid-derived suppressor cells (MDSC) infiltration and differentiation, and boosts CD8+ T cell memory and effector function. Ipatasertib is an oral highly selective small-molecule inhibitor of all three isoforms of AKT. This phase 2 trial is designed to compare progression-free survival (PFS) in first line R/M, HNSCC patients treated with the combination ipatasertib and pembrolizumab versus pembrolizumab monotherapy treatment. Methods: In this open-label randomized phase 2 multicenter trial, patients with R/M HNSCC are treated with pembrolizumab 200mg on day 1 +/- ipatasertib 400mg QD days 1-14 of 21-day cycles. Patients must have PD-L1 CPS score ³ 1, have measurable disease per RECIST 1.1, and consent to on-treatment biopsy. Patients will be excluded if they have received prior systemic therapy for R/M HNSCC, cannot swallow a pill, or require insulin for diabetes. The primary objective is to compare the PFS between the two arms. We will estimate the relative hazard ratio associated with ipatasertib plus pembrolizumab compared to pembrolizumab alone using the Cox Model where randomized treatment assignment is the only variable in the model. Secondary objectives include ORR, safety and tolerability of the combination, and changes in tumor immune cell infiltration, AKT signaling, and changes in peripheral blood immune cells. Ultimately, a total of 48 patients will be enrolled, with 24 patients in each cohort. To date, a total of 22 patients have been enrolled from 15 sites. Accrual is ongoing (NCT05172258). Clinical trial information: NCT05172258 .

INTerpath-001: Pembrolizumab with V940 (mRNA-4157) versus pembrolizumab with placebo for adjuvant treatment of high-risk stage II-IV melanoma.

TPS9616 Background: The anti−PD-1 antibody pembrolizumab is approved as adjuvant therapy for stage IIB-C and stage III melanoma by AJCC 8th ed, following complete resection. Adjuvant pembrolizumab has improved recurrence-free survival (RFS) and distant metastasis-free survival (DMFS) in patients with high-risk melanoma, but many patients experience disease recurrence. In the randomized phase 2b KEYNOTE-942 study, the individualized neoantigen therapy V940 showed improved RFS and DMFS when used in combination with pembrolizumab versus pembrolizumab monotherapy in patients with stage III or IV melanoma. INTerpath-001 (NCT05933577) is a double-blind phase 3 randomized controlled trial designed to evaluate the efficacy and safety of adjuvant pembrolizumab plus V940 versus pembrolizumab plus placebo in patients with resected high-risk stage II-IV melanoma. Methods: Eligible patients are aged ≥18 years with surgically resected stage IIB or IIC (pathologic or clinical), III, or IV cutaneous melanoma per AJCC 8th ed and an Eastern Cooperative Oncology Group performance status of 0 or 1. Patients are ineligible if they have received any prior systemic therapy and if more than 13 weeks has elapsed between last surgical resection and first dose of pembrolizumab. Patients with ocular or mucosal melanoma and past or current in-transit metastases or satellitosis are excluded. All patients must provide a blood sample and a formalin-fixed, paraffin-embedded tumor sample for sequencing. Patients will be stratified by risk (IIB, IIC, IIIA, and IIIB vs IIIC/D and IV) and age (<65 years vs ≥65 years). Approximately 1089 patients will be randomly assigned 2:1 to receive pembrolizumab 400 mg plus V940 1 mg or pembrolizumab 400 mg with placebo. Pembrolizumab will be administered intravenously every 6 weeks and v940 or placebo will be administered intramuscularly every 3 weeks. Treatment will continue for up to 9 doses or until disease recurrence, unacceptable toxicity, or patient withdrawal. The primary end point is RFS by investigator review. Secondary end points are DMFS by investigator review, overall survival, safety and tolerability, and quality of life. Hazard ratios and 95% CIs will be estimated using a stratified Cox regression model with the Efron method of handling ties. Between-treatment differences will be evaluated using a stratified log-rank test. Enrollment is ongoing. Clinical trial information: NCT05933577 .

HB-200 arenavirus-based immunotherapy plus pembrolizumab as first-line treatment of patients with recurrent/metastatic HPV16-positive head and neck cancer: Updated results.

6005 Background: Treatment options are limited for patients with recurrent/metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) with no approved treatment specifically targeting human papillomavirus (HPV) 16-positive tumors. In the first-line (1L) R/M setting, only a minority of patients (~20%) respond to pembrolizumab monotherapy, including those with high programmed death ligand 1 (PD-L1) expression in the tumor. HB-200 comprises an alternating sequence of two replicating attenuated arenavirus vectors derived from LCMV (HB-201) and Pichinde virus (HB-202), respectively. HB-200 vectors express a non-oncogenic HPV16 E7E6 fusion protein and induce E6 and E7-specific CD8 T-cell responses. Previously, we reported promising preliminary clinical activity of HB-200 in combination with pembrolizumab as 1L treatment for patients with HPV16+ PD-L1+ R/M HNSCC. Here, we report updated results with a focus on PD-L1 status. Methods: In this non-randomized Phase 2 part of the study, participants with HPV16+ PD-L1 combined positive score (CPS) ≥1 R/M HNSCC were treated with HB-200 intravenously (every 3 weeks [Q3W] then Q6W) in combination with pembrolizumab (200 mg Q3W or 400 mg Q6W). Safety, T cell response, and preliminary antitumor activity were assessed. Results: As of 12 January 2024, 42 patients with HPV16+ PD-L1+ R/M HNSCC (41 of oropharynx as primary cancer site) were treated with HB-200 plus pembrolizumab in the 1L setting. Median follow-up time was 5.6 months. Characteristics of this cohort included: median age 66 years (range 50-77), 41 (98%) male, 37 (88%) White, 14 (33%) with ≥ 10 pack/year smoking history, 40 (95%) check point inhibitor (CPI) naïve (2 received CPI in the adjuvant setting), and 21 (50%) with PD-L1 CPS ≥ 20. HB-200 + pembrolizumab were generally well tolerated. Grade ≥3 treatment-related adverse events (TRAEs) were reported in 6 (14%) patients, serious TRAEs in 3 (7%) patients, and TRAEs leading to treatment discontinuation in 2 (5%) patients. No treatment-related death were reported. Among 35 evaluable patients (those with ≥ 1 tumor response assessments), the overall response rate (ORR) was 43% (3 complete response [CR], 9 partial response [PR], 3 unconfirmed PR) and the disease control rate (DCR) was 71%. Notably, among patients with PD-L1 CPS ≥20 (N = 17), ORR was 59% (3 CR, 6 PR, 1 unconfirmed PR) and DCR was 88%. Conclusions: Updated data of HB-200 arenavirus-based immunotherapy plus pembrolizumab continued to demonstrate a favorable safety profile and promising clinical activity as 1L treatment in patients with HPV16+ PD-L1+ R/M HNSCC and confirms previously reported data. The results suggest that the subgroup of patients with PD-L1 CPS ≥20 may benefit more from this treatment, which warrants further development in a randomized pivotal study. Clinical trial# NCT04180215. Clinical trial information: NCT04180215 .

Safety and preliminary efficacy of EIK1001 in combination with pembrolizumab in participants with advanced solid tumors.

2521 Background: Immune checkpoint inhibitors (ICIs) relieve immunosuppression of tumor-reactive T cells and enhance antitumor immune response; however, not all patients benefit and some become refractory. EIK1001 is a Toll-like receptor (TLR)7/8 agonist that stimulates myeloid and plasmacytoid dendritic cells, activating immune and inflammatory responses. This dual activity provides another pathway, distinct from effects on checkpoint proteins, to enhance antitumor T-cell activity alone or in combination with ICIs. Methods: Study BDB001-101 was a Phase 1, open-label, dose-escalation/expansion study of EIK1001 as either monotherapy (mono Rx; previously reported) or combined with pembrolizumab (comb Rx). Enrollment criteria included participants (pts) ≥ age 18 with confirmed, RECIST-measurable advanced solid tumors. Primary study objectives included safety and tolerability, and secondary objectives included evaluation of dose-limiting toxicities, pharmacokinetics (PK), pharmacodynamics, and preliminary efficacy by RECIST 1.1. During comb Rx dose escalation, pts received a range of doses of EIK1001 (QW IV) in combination with pembrolizumab (200 mg Q3W). Results: Fifty-one pts (median age 67 [range 33 to 86]) with multiple, distinct histological tumor types and with a median of 3 prior Rx regimens were enrolled. Overall, a total of 42/51 (82.4%) comb Rx pts experienced a treatment-related adverse event (TRAE). A total of 9/51 (17.7%) experienced a ≥ Grade 3 TRAE, including fatigue, cytokine release syndrome (CRS), hemiparesis, hypertension, joint range of motion reduced, muscular weakness, pancreatitis, rash (maculopapular), skin plaque, and stomatitis. Overall, 5/51 (9.8%) experienced manageable CRS, with only 1 discontinuation due to CRS. There were no deaths due to TRAEs. Of the efficacy-evaluable pts (n = 50), complete response (CR) or partial response (PR) was observed for 7/50 (14.0%), including 3 CR and 4 PR. Disease control (including CR, PR, or stable disease) was observed in 24/50 (48.0%). The median duration of response was 10 months (range = 4 to 32 months). Responses were observed in pts with prior anti-PD-1 exposure as well as in those with low or negative PD-L1 tumor expression. EIK1001 PK was linear and dose-proportional, and combination with pembrolizumab did not affect EIK1001 PK. Conclusions: Overall, EIK1001 was well-tolerated with a manageable safety profile and showed encouraging preliminary efficacy across several tumor types in combination with pembrolizumab. Responses were observed even in heavily pretreated patients not anticipated to respond to pembrolizumab monotherapy. Further development of EIK1001 is underway. Clinical trial information: NCT03486301 .

EE63 Cost-Effectiveness and Budget Impact of Pembrolizumab Monotherapy As the First-Line Treatment for Metastatic Non-Small Cell Lung Cancer Patients with PD-L1 ≥ 50% in Thailand

EE63 Cost-Effectiveness and Budget Impact of Pembrolizumab Monotherapy As the First-Line Treatment for Metastatic Non-Small Cell Lung Cancer Patients with PD-L1 ≥ 50% in Thailand

Association of human leukocyte antigen (HLA) status with immune checkpoint inhibitor (ICI) pneumonitis in patients with non-small cell lung cancer (NSCLC).

8620 Background: Pneumonitis is a potentially serious complication occurring in 5-20% of lung cancer patients receiving ICI. The genetic risk factors for ICI pneumonitis are unclear. Given the association between HLA genetic variants and autoimmune diseases, we hypothesized that certain HLA genetic variants are associated with risk of ICI pneumonitis. Methods: Patients with advanced EGFR/ ALK wild type, PD-L1 tumor proportion score ≥50% NSCLC who received ICI were enrolled from year 2019 to 2022. Germline HLA typing was performed on buccal swab specimens using the Alltype Fastplex assay. Clinicopathological characteristics, treatment courses and survival outcomes were retrospectively collated. The primary endpoint was the correlation of common HLA variants (present in >30% of subjects) to the risk of ICI pneumonitis. Results: 42 patients (all Chinese, 36 male, 33 current/former smokers) were enrolled. Median age was 71 years old (range 51-91). 34, 6, 1 and 1 patients had adenocarcinoma, NSCLC not otherwise specified, squamous cell carcinoma and large cell neuroendocrine carcinoma respectively. Majority (33/42, 79%) received pembrolizumab monotherapy while 9 (21%) patients received pembrolizumab plus chemotherapy. Median follow up time was 27.8 months. At data cutoff, 28 (67%) patients received ICI for more than 1 year and 10 (24%) patients stopped ICI after completion of 2-year course of treatment. Seven (17%) patients developed pneumonitis, of which 3 were grade 2 and 4 were grade 3 in severity. Median time to development of pneumonitis was 6.9 months (range 0.3-25.2). Demographic characteristics were similar between patients who did or did not experience pneumonitis. In the entire cohort, twenty-two (52%) patients harbored the class II DPB1*02 allele. This allele was significantly associated with development of ICI pneumonitis. All 7 patients who had ICI pneumonitis harbored the DPB1*02 allele. The incidence of pneumonitis in patients harboring the DPB1*02 allele was 32% compared to 0% in those without this allele (p=0.009). Patients who experienced pneumonitis had worse survival rates than those without (p=0.03), but expression of DPB1*02 allele was not associated with inferior survival outcomes. Conclusions: Our results suggested that expression of DPB1*02 allele may be associated with development of ICI pneumonitis. A larger case-control study is ongoing to validate this association. [Table: see text]

Health outcomes of pembrolizumab plus chemotherapy in non-small cell lung cancer.

e20527 Background: Pembrolizumab (PEM) is a standard of treatment for advanced or metastatic non-small cell lung cancer (m-nSCLC) in tumors without biomarker actionable. The clinical practice protocol for m-nSCLC in our hospital includes PEM monotherapy if PD-L1 ≥50% and PEM+chemotherapy (PEM+CT) if PD-L1 1-49% or negative. The aim of this study is to determine the effectiveness results of PEM+CT in m-nSCLC in real clinical practice. Methods: It was designed a single center, observational and retrospective study. We included all patients (pts) treated with PEM+CT as first line of therapy with m-nSCLC of September-2019 to August-2023 at a hospital from south Spain, cut-off date 11/30/2023. The primary endpoints were overall survival (OS) and progression-free survival (PFS). The results were analyzed for population and by subgroups (histology, ECOG, previous localized disease (LD) and other), using Kaplan-Meier method. Results: 103 pts were enrolled (89% men), mean age was 66.2 years, 48.5% of pts had ECOG 0, 40.8% ECOG 1 and the rest ECOG 2-3. The tumors were 64.1 % non-squamous histology. 28.2% pts were treated for previous localized disease and 39.8% pts received radiation therapy at some point during treatment. At start of therapy the mean WBC count with PEM+CT was 10.0 x10(9)/L (sd=6.2). With a median follow-up of 10.8 months (m) the median for treatment duration was 5.7 m [95%CI 4.3-7.2].PFS was 7.2 m [IC95% 5.9-8.6] for all pts, 6.6 m [IC95% 4.6-8.7] for non-squamous and 8.2 m [IC95% 4.6-11.7] for squamous histology, p=0.158. OS was 14.2 m [IC95% 10.2-18.2] for all pts, 13.1 m [IC95% 7.6-18.6] and 14.2 [IC95% 9.3-19.2] by non-squamous and squamous histology, respectively, p=0.396.We found statistically significant difference in OS between: pts with ECOG 0-1 (median 15.1 m [IC95% 11.6-18.7]) vs pts with EOCG 2-3 (median 6.6 m [IC95% 1.6-11.6]), p=0.046 and pts previously treated pts of LD (median 21.7 m [IC95% 2.5-40.8]) vs pts with advanced or metastatic disease at onset (median 10.5 m [IC95% 5.2-15.9]), p=0.025. Another subgroup analysis is shown in table. Conclusions: The effectiveness of PEM+CT was similar in OS and PFS values to that of the pivotal trials. In contrast to these, our results were slightly better in squamous histology. The OS was better in pts with ECOG 0-1 and previously treated of localized disease, highlighting the importance of early diagnosis. [Table: see text]

Projected environmental and public health benefits of extended-interval dosing: an analysis of pembrolizumab use in a US national health system

Health care is a major source of greenhouse gas emissions, leading to climate change and public health harms. Changes are needed to improve the environmental sustainability of health-care practices, but such changes should not sacrifice patient outcomes or financial sustainability. Alternative dosing strategies that reduce the frequency with which specialty drugs are administered, without sacrificing patient outcomes, are an attractive possibility for improving environmental sustainability. We sought to inform environmentally sustainable cancer care by estimating and comparing the environmental and financial effects of alternative, clinically equivalent strategies for pembrolizumab administration. We conducted a retrospective analysis using a cohort of patients from the Veterans Health Administration (VHA) in the USA who received one or more pembrolizumab doses between May 1, 2020, and Sept 30, 2022. Using baseline, real-world administration of pembrolizumab, we generated simulated pembrolizumab use data under three near-equivalent counterfactual pembrolizumab administration strategies defined by combinations of weight-based dosing, pharmacy-level vial sharing and dose rounding, and extended-interval dosing (ie, every 6 weeks). For each counterfactual dosing strategy, we estimated greenhouse gas emissions related to pembrolizumab use across the VHA cohort using a deterministic environmental impact model that estimated greenhouse gas emissions due to patient travel, drug manufacture, and medical waste as the primary outcome measure. We identified 7813 veterans who received at least one dose of pembrolizumab-containing therapy in the VHA during the study period. 59 140 pembrolizumab administrations occurred in the study period, of which 46 255 (78·2%) were dosed at 200 mg every 3 weeks, 12 885 (21·8%) at 400 mg every 6 weeks, and 14 955 (25·3%) were coadministered with infusional chemotherapies. Adoption of weight-based, extended-interval pembrolizumab dosing (4 mg/kg every 6 weeks) and pharmacy-level stewardship strategies (ie, dose rounding and vial sharing) for all pembrolizumab infusions would have resulted in 24·7% fewer administration events than baseline dosing (44 533 events vs 59 140 events) and an estimated 200 metric tons less CO2 emitted per year as a result of pembrolizumab use within the VHA (650 tons vs 850 tons of CO2, a relative reduction of 24%), largely due to reductions in distance travelled by patients to receive treatment. Similar results were observed when weight-based and extended-interval dosing were applied only to pembrolizumab monotherapy and pembrolizumab in combination with oral therapies. Alternative pembrolizumab administration strategies might have environmental advantages over the current dosing and compounding paradigms. Specialty medication dosing can be optimised for health-care spending and environmental sustainability without sacrificing clinical outcomes. None.

Durable pembrolizumab response in metastatic MSS ARID1A-mutant undifferentiated carcinoma of the esophagus.

In 2021, the FDA approved the combination of pembrolizumab with platinum and fluoropyrimidine-based chemotherapy for advanced esophageal and gastroesophageal junction (GEJ) cancers, regardless of the PD-L1 score. Pembrolizumab alone may benefit MSI-H gastroesophageal adenocarcinomas, but most patients with pMMR/MSS types require it in combination with standard chemotherapy. The NCCN recognizes the predictive value of PD-L1 CPS and recommends pembrolizumab plus chemotherapy for PD-L1 CPS ≥10. Undifferentiated carcinoma of the esophagus, a rare esophageal cancer subtype with a poor prognosis, still lacks a well-defined optimal treatment. We report a case of an 87-year-old female with advanced, pMMR/MSS, HER2-negative, ARID1A-mutant, undifferentiated carcinoma of the esophagus with a PD-L1 CPS of 20, who has shown a durable ongoing response to pembrolizumab monotherapy for 2 years now. The case highlights a favorable response, possibly attributed to the high CPS score combined with the ARID1A mutation, as recent research suggests that ARID1A mutations may increase immunotherapy susceptibility.

Pembrolizumab monotherapy for high-risk non-muscle-invasive bladder cancer without carcinoma in situ and unresponsive to BCG (KEYNOTE-057): a single-arm, multicentre, phase 2 trial

The KEYNOTE-057 trial evaluated activity and safety of pembrolizumab in patients with BCG-unresponsive high-risk non-muscle-invasive bladder cancer who were ineligible for or declined radical cystectomy. In cohort A (patients with carcinoma in situ, with or without papillary tumours) of the KEYNOTE-057 study, pembrolizumab monotherapy led to a complete response rate of 41% at 3 months, and 46% of responders maintained a response lasting at least 12 months. Here, we evaluate pembrolizumab monotherapy in cohort B of patients with papillary tumours without carcinoma in situ. KEYNOTE-057 is a single-arm, phase 2 study in 54 sites (hospitals and cancer centres) in 14 countries. Cohort B eligible patients were aged 18 years and older, had an Eastern Cooperative Oncology Group performance status of 0-2, and had BCG-unresponsive high-risk non-muscle-invasive bladder cancer with papillary tumours (high-grade Ta or any-grade T1) without carcinoma in situ. Transurethral resection of bladder tumour within 12 weeks of first pembrolizumab dose was required. Patients received pembrolizumab 200 mg intravenously every 3 weeks for a maximum of 35 cycles. Primary endpoint was 12-month disease-free survival of high-risk non-muscle-invasive bladder cancer or progressive disease as assessed by cystoscopy, cytology, and central pathology and radiology review. Activity was assessed in all patients who received at least one dose of the study drug and had a baseline evaluation. Safety was assessed in all patients who received at least one dose of the study drug. This trial is registered with ClinicalTrials.gov number, NCT02625961, and is ongoing. Between April 12, 2016, and June 17, 2021, 132 patients (104 [79%] men and 28 [21%] women) who had received a median of ten (IQR 9-15) previous BCG instillations were enrolled into cohort B of the study. Patients received a median of 10 cycles (IQR 6-27) of pembrolizumab. At data cutoff date, Oct 20, 2022, median follow-up was 45·4 months (IQR 36·4-59·3) and five (4%) of 132 patients remained on treatment. The 12-month disease-free survival was 43·5% (95% CI 34·9-51·9). Treatment-related adverse events occurred in 97 (73%) of 132 patients; 19 (14%) had a grade 3 or 4 treatment-related adverse event; the most common grade 3 or 4 treatment-related adverse events were colitis (in three [2%] patients) and diarrhoea (in two [2%]). 17 (13%) of 132 patients experienced serious treatment-related adverse events, of which colitis (three patients [2%]) was most common. No treatment-related deaths occurred. Pembrolizumab monotherapy showed antitumour activity and manageable toxicity in patients with BCG-unresponsive high-risk Ta or T1 bladder cancer without carcinoma in situ and could potentially be a suitable treatment option for patients who decline or are ineligible for radical cystectomy. Findings will need to be confirmed in a randomised controlled trial. Merck Sharp & Dohme.

Real-World Safety and Outcome of First-Line Pembrolizumab Monotherapy for Metastatic NSCLC with PDL-1 Expression ≥ 50%: A National Italian Multicentric Cohort ("PEMBROREAL" Study).

Results from the phase III Keynote-024 clinical trial established pembrolizumab monotherapy as the first-line standard of care for patients with metastatic NSCLC who have PD-L1 expression ≥ 50%, EGFR, and ALK wild-type tumors. However, given the differences between patients treated in routine clinical practice and those treated in a clinical trial, real-world data are needed to confirm the treatment benefit in standard practice. Given the lack of data on large cohorts of patients with long follow-ups, we designed an observational retrospective study of patients with metastatic NSCLC who were treated with pembrolizumab, starting from its reimbursement eligibility until December 2020. The primary endpoints were PFS and OS, determined using the Kaplan-Meier method. Response and safety were also evaluated. We followed 880 patients (median follow-up: 35.1 months) until February 2022. Median PFS and OS were 8.6 months (95% CI: 7.6-10.0) and 25.5 months (95% CI: 21.8-31.6), respectively. We also found that ECOG PS, PD-L1 expression, and habitual smoking were prognostic factors for PFS, while age, sex, ECOG PS, habitual smoking and histology had an impact on OS. Multivariable analysis confirms the prognostic role of PD-L1 for PFS and of ECOG for both PFS and OS. 39.9% of patients reported an adverse event, but only 6.3% of patients discontinued therapy due to toxicity. Our results suggest a long-term benefit of pembrolizumab in the first-line setting, as well as a safety profile consistent with the results of Keynote-024. Many collected variables appear to influence clinical outcome, but results from these exploratory unadjusted analyses should be interpreted with caution.