Neoadjuvant and adjuvant pembrolizumab plus chemotherapy in locally advanced gastric or gastro-oesophageal cancer (KEYNOTE-585): an interim analysis of the multicentre, double-blind, randomised phase 3 study

BACKGROUND

The benefit of combination neoadjuvant and adjuvant chemotherapy and immune checkpoint inhibition in patients with locally advanced, resectable gastric or gastro-oesophageal adenocarcinoma is unknown. We assess the antitumor activity of neoadjuvant and adjuvant pembrolizumab plus chemotherapy in patients with locally advanced resectable gastric or gastro-oesophageal adenocarcinoma.

METHODS

The KEYNOTE-585 study is a multicentre, randomised, placebo-controlled, double-blind, phase 3 study done at 143 medical centres in 24 countries. Eligible patients were aged 18 years or older with untreated, locally advanced, resectable gastric or gastro-oesophageal adenocarcinoma, and an Eastern Cooperative Oncology Group performance status 0-1. Patients were randomly assigned (1:1) by an interactive voice response system and integrated web response system to neoadjuvant pembrolizumab 200 mg intravenously or placebo (saline) plus cisplatin-based doublet chemotherapy (main cohort) every 3 weeks for 3 cycles, followed by surgery, adjuvant pembrolizumab or placebo plus chemotherapy for 3 cycles, then adjuvant pembrolizumab or placebo for 11 cycles. A small cohort was also randomly assigned (1:1) to pembrolizumab or placebo plus fluorouracil, docetaxel, and oxaliplatin (FLOT)-based chemotherapy (FLOT cohort) every 2 weeks for four cycles, followed by surgery, adjuvant pembrolizumab, or placebo plus FLOT for four cycles, then adjuvant pembrolizumab or placebo for 11 cycles. Patients were stratified by geographic region, tumour stage, and chemotherapy backbone. Primary endpoints were pathological complete response (reviewed centrally), event-free survival (reviewed by the investigator), and overall survival in the intention-to-treat population, and safety assessed in all patients who received at least one dose of study treatment. The study is registered at ClinicalTrials.gov, NCT03221426, and is closed to accrual.

FINDINGS

Between Oct 9, 2017, and Jan 25, 2021, of 1254 patients screened, 804 were randomly assigned to the main cohort, of whom 402 were assigned to the pembrolizumab plus cisplatin-based chemotherapy group and 402 to the placebo plus cisplatin-based chemotherapy group, and 203 to the FLOT cohort, of whom 100 were assigned to the pembrolizumab plus FLOT group and 103 to placebo plus FLOT group. In the main cohort of 804 participants, 575 (72%) were male and 229 (28%) were female. In the main cohort, after median follow-up of 47·7 months (IQR 38·0-54·8), pembrolizumab was superior to placebo for pathological complete response (52 [12·9%; 95% CI 9·8-16·6] of 402 vs eight [2·0%; 0·9-3·9] of 402; difference 10·9%, 95% CI 7·5 to 14·8; p<0·00001). Median event-free survival was longer with pembrolizumab versus placebo (44·4 months, 95% CI 33·0 to not reached vs 25·3 months, 20·6 to 33·9; hazard ratio [HR] 0·81, 95% CI 0·67 to 0·99; p=0·0198) but did not meet the threshold for statistical significance (p=0·0178). Median overall survival was 60·7 months (95% CI 51·5 to not reached) in the pembrolizumab group versus 58·0 months (41·5 to not reached) in the placebo group (HR 0·90, 95% CI 0·73 to 1·12; p=0·174). Grade 3 or worse adverse events of any cause occurred in 312 (78%) of 399 patients in the pembrolizumab group and 297 (74%) of 400 patients in the placebo group; the most common were nausea (240 [60%] vs 247 [62%]), anaemia (168 [42%] vs 158 [40%]), and decreased appetite (163 [41%] vs 172 [43%]). Treatment-related serious adverse events were reported in 102 (26%) and 97 (24%) patients. Treatment-related adverse events that led to death occurred in four (1%) patients in the pembrolizumab group (interstitial ischaemia, pneumonia, decreased appetite, and acute kidney injury [n=1 each]) and two (<1%) patients in the placebo group (neutropenic sepsis and neutropenic colitis [n=1 each]).

INTERPRETATION

Although neoadjuvant and adjuvant pembrolizumab versus placebo improved the pathological complete response, it did not translate to significant improvement in event-free survival in patients with untreated, locally advanced resectable gastric or gastro-oesophageal cancer.

FUNDING

Merck Sharp & Dohme.

Pembrolizumab plus trastuzumab and chemotherapy for HER2-positive gastric or gastro-oesophageal junction adenocarcinoma: interim analyses from the phase 3 KEYNOTE-811 randomised placebo-controlled trial

BACKGROUND

Evidence for the efficacy of combined PD-1 and HER2 blockade with chemotherapy on progression-free and overall survival in HER2-positive gastro-oesophageal cancer is scarce. The first interim analysis of the randomised, phase 3 KEYNOTE-811 study showed a superior objective response with pembrolizumab compared with placebo when added to trastuzumab plus fluoropyrimidine and platinum-based chemotherapy. Here, we report results from protocol-specified subsequent interim analyses of KEYNOTE-811.

METHODS

The randomised, phase 3 KEYNOTE-811 trial involved 168 medical centres in 20 countries worldwide. Patients aged 18 years or older with locally advanced or metastatic HER2-positive gastro-oesophageal junction adenocarcinoma, without previous first-line treatment, were randomly assigned (1:1) by an integrated interactive voice-response and web-response system to intravenous pembrolizumab 200 mg or placebo, both to be combined with standard chemotherapy (fluoropyrimidine and platinum-based therapy) plus trastuzumab every 3 weeks for up to 35 cycles or until disease progression, unacceptable toxic effects, or investigator or participant-initiated withdrawal. Randomisation used a block size of four and was stratified by region, PD-L1 status, and chemotherapy. Dual primary endpoints were progression-free and overall survival, analysed by intention to treat. Safety was assessed in all randomly assigned patients who received at least one dose of study treatment according to the treatment received. KEYNOTE-811 is registered with ClinicalTrials.gov (NCT03615326) and is active but not recruiting.

FINDINGS

Between Oct 5, 2018, and Aug 6, 2021, 698 patients were assigned to pembrolizumab (n=350) or placebo (n=348). 564 (81%) were male and 134 (19%) were female. At the third interim analysis, 286 (82%) of 350 patients in the pembrolizumab group and 304 (88%) of 346 in the placebo group who received treatment had discontinued treatment, mostly due to disease progression. At the second interim analysis (median follow-up 28·3 months [IQR 19·4-34·3] in the pembrolizumab group and 28·5 months [20·1-34·3] in the placebo group), median progression-free survival was 10·0 months (95% CI 8·6-11·7) in the pembrolizumab group versus 8·1 months (7·0-8·5) in the placebo group (hazard ratio [HR] 0·72, 95% CI 0·60-0·87; p=0·0002). Median overall survival was 20·0 months (17·8-23·2) versus 16·9 months (15·0-19·8; HR 0·87 [0·72-1·06]; p=0·084). At the third interim analysis (median follow-up 38·4 months [IQR 29·5-44·4] in the pembrolizumab group and 38·6 months [30·2-44·4] in the placebo group), median progression-free survival was 10·0 months (8·6-12·2) versus 8·1 months (7·1-8·6; HR 0·73 [0·61-0·87]), and median overall survival was 20·0 months (17·8-22·1) versus 16·8 months (15·0-18·7; HR 0·84 [0·70-1·01]), but did not meet prespecified criteria for significance and will continue to final analysis. Grade 3 or worse treatment-related adverse events occurred in 204 (58%) of 350 patients in the pembrolizumab group versus 176 (51%) of 346 patients in the placebo group. Treatment-related adverse events that led to death occurred in four (1%) patients in the pembrolizumab group and three (1%) in the placebo group. The most common treatment-related adverse events of any grade were diarrhoea (165 [47%] in the pembrolizumab group vs 145 [42%] in the placebo group), nausea (154 [44%] vs 152 [44%]), and anaemia (109 [31%] vs 113 [33%]).

INTERPRETATION

Compared with placebo, pembrolizumab significantly improved progression-free survival when combined with first-line trastuzumab and chemotherapy for metastatic HER2-positive gastro-oesophageal cancer, specifically in patients with tumours with a PD-L1 combined positive score of 1 or more. Overall survival follow-up is ongoing and will be reported at the final analysis.

FUNDING

Merck Sharp & Dohme.

Pembrolizumab plus chemotherapy versus placebo plus chemotherapy for HER2-negative advanced gastric cancer (KEYNOTE-859): a multicentre, randomised, double-blind, phase 3 trial

BACKGROUND

PD-1 inhibitors combined with chemotherapy have shown efficacy in gastric or gastro-esophageal junction cancer. We compared the efficacy and safety of pembrolizumab plus chemotherapy with placebo plus chemotherapy in participants with locally advanced or metastatic HER2-negative gastric or gastro-esophageal junction adenocarcinoma.

METHODS

KEYNOTE-859 is a multicentre, double-blind, placebo-controlled, randomised, phase 3 trial, done at 207 medical centres across 33 countries. Eligible participants were aged 18 years and older with previously untreated histologically or cytologically confirmed locally advanced or metastatic HER2-negative gastric or gastro-esophageal junction adenocarcinoma and an Eastern Cooperative Oncology Group performance status of 0 or 1. Patients were randomly assigned (1:1) to receive pembrolizumab or placebo 200 mg, administered intravenously every 3 weeks for up to 35 cycles. All participants received investigator's choice of fluorouracil (intravenous, 800 mg/m2 per day) administered continuously on days 1-5 of each 3-week cycle plus cisplatin (intravenous, 80 mg/m2) administered on day 1 of each 3-week cycle or capecitabine (oral, 1000 mg/m2) administered twice daily on days 1-14 of each 3-week cycle plus oxaliplatin (intravenous, 130 mg/m2) administered on day 1 of each 3-week cycle. Randomisation was done using a central interactive voice-response system and stratified by geographical region, PD-L1 status, and chemotherapy in permuted block sizes of four. The primary endpoint was overall survival, assessed in the intention-to-treat (ITT) population, and the populations with a PD-L1 combined positive score (CPS) of 1 or higher, and PD-L1 CPS of 10 or higher. Safety was assessed in the as-treated population, which included all randomly assigned participants who received at least one dose of study intervention. Here, we report the results of the interim analysis. This study is registered with ClinicalTrials.gov, NCT03675737, and recruitment is complete.

FINDINGS

Between Nov 8, 2018, and June 11, 2021, 1579 (66%) of 2409 screened participants were randomly assigned to receive pembrolizumab plus chemotherapy (pembrolizumab group; n=790) or placebo plus chemotherapy (placebo group; n=789). Most participants were male (527 [67%] of 790 participants in the pembrolizumab plus chemotherapy group; 544 [69%] of 789 participants in the placebo plus chemotherapy group) and White (426 [54%]; 435 [55%]). Median follow-up at the data cutoff was 31·0 months (IQR 23·0-38·3). Median overall survival was longer in the pembrolizumab group than in the placebo group in the ITT population (12·9 months [95% CI 11·9-14·0] vs 11·5 months [10·6-12·1]; hazard ratio [HR] 0·78 [95% CI 0·70-0·87]; p<0·0001), in participants with a PD-L1 CPS of 1 or higher (13·0 months [11·6-14·2] vs 11·4 months [10·5-12·0]; 0·74 [0·65-0·84]; p<0·0001), and in participants with a PD-L1 CPS of 10 or higher (15·7 months [13·8-19·3] vs 11·8 months [10·3-12·7]; 0·65 [0·53-0·79]; p<0·0001). The most common grade 3-5 adverse events of any cause were anaemia (95 [12%] of 785 participants in the pembrolizumab group vs 76 [10%] of 787 participants in the placebo group) and decreased neutrophil count (77 [10%] vs 64 [8%]). Serious treatment-related adverse events occurred in 184 (23%) participants in the pembrolizumab group and 146 (19%) participants in the placebo group. Treatment-related deaths occurred in eight (1%) participants in the pembrolizumab group and 16 (2%) participants in the placebo group. No new safety signals were identified.

INTERPRETATION

Participants in the pembrolizumab plus chemotherapy group had a significant and clinically meaningful improvement in overall survival with manageable toxicity compared with participants in the placebo plus chemotherapy group. Therefore, pembrolizumab with chemotherapy might be a first-line treatment option for patients with locally advanced or metastatic HER2-negative gastric or gastro-esophageal junction adenocarcinoma.

FUNDING

Merck Sharp and Dohme.

KEYMAKER-U06 substudy 06A trial in progress: A phase 1/2 study of investigational agents with pembrolizumab (pembro) plus chemotherapy (chemo) or lenvatinib in PD-1/L1 treatment-naïve advanced esophageal cancer

TPS487

Background: Immunotherapy has improved clinical outcomes in esophageal carcinoma; however, patients with advanced esophageal cancer that progresses after first-line chemo continue to have limited treatment options and poor prognosis. KEYMAKER-U06 substudy 06A (NCT05342636) is evaluating pembro (anti–PD-1) + investigator choice of chemo (irinotecan or paclitaxel), MK-4280A, a coformulation of pembro and favezelimab (anti-LAG3) + chemo, pembro + MK-4830 (anti-ILT4) + chemo, and pembro + MK-4830 + lenvatinib (multitargeted RTK inhibitor) for the second-line treatment of patients with PD-1/L1 treatment-naive advanced esophageal squamous cell carcinoma (ESCC). Methods: KEYMAKER-U06 substudy 06A is a phase 1/2, multicenter, open-label study comprising a safety lead-in phase and an efficacy phase. Adults with histologically or cytologically confirmed metastatic or locally advanced ESCC, who experienced disease progression on 1 prior line of therapy, have not received anti-PD-1/L1 therapy, any immune-modulating therapy, and/or VEGF targeted therapy, have measurable disease per RECIST v1.1 confirmed by blinded independent central review (BICR), and have an Eastern Cooperative Oncology Group performance status of 0 or 1 are eligible. Patients are being allocated to 1 of 4 treatment arms: pembro 200 mg IV Q3W + investigator choice of chemo (paclitaxel 80-100 mg/m2 IV days 1, 8, and 15 of every 28-day cycle or irinotecan 180 mg/m2 day 1 of every 14-day cycle) (arm 1), MK-4280A (pembro 200 mg/favezelimab 800 mg IV day 1 then Q3W) + investigator choice of chemo (arm 2), pembro 200 mg IV Q3W + MK-4830 800 mg IV Q3W + investigator choice of chemo (arm 3), or pembro 200 mg IV Q3W + MK-4830 800 mg IV Q3W + lenvatinib 20 mg orally once daily (arm 4). Arms 2-4 will have a safety lead-in phase; arm 1 will not have a safety lead-in phase because the safety and tolerability of pembro + chemo has been established in multiple phase 3 studies in the first-line treatment setting. The safety lead-in phase includes 10 patients who will be closely monitored for dose-limiting toxicities (DLTs) for 21 days after the first dose of study intervention. If ≥4 patients experience DLTs in any treatment arm, then enrollment in the efficacy phase may be delayed to allow for examination of safety data and to consider design changes. If ≤3 patients experience DLTs, up to 30 patients per arm will be enrolled (inclusive of the 10 patients from the safety lead-in) for efficacy assessment. In the safety lead-in phase, the primary end point is safety/tolerability assessed by DLTs, adverse events (AEs), and discontinuation of treatment due to AEs. In the efficacy phase, the primary end point is ORR per RECIST v1.1 by BICR, and secondary end points are PFS and DOR, per RECIST v1.1 by BICR, and OS and safety/tolerability. Enrollment in this study is ongoing. Clinical trial information: NCT05342636 .

First-line lenvatinib plus pembrolizumab plus chemotherapy versus chemotherapy in advanced/metastatic gastroesophageal adenocarcinoma (LEAP-015): Safety run-in results

411

Background: LEAP-015 (NCT04662710) is a randomized, open-label, 2-part, phase 3 study of the safety and efficacy of lenvatinib + pembrolizumab + chemotherapy as a first-line treatment for advanced/metastatic gastroesophageal adenocarcinoma. We report findings from part 1, the safety run-in, of LEAP-015. Methods: Eligible patients had untreated, HER2-negative, locally advanced unresectable or metastatic gastroesophageal adenocarcinoma, measurable disease per RECIST v1.1, and ECOG performance status 0 or 1. In part 1, patients received induction with IV pembrolizumab 400 mg Q6W (×2) + oral lenvatinib 8 mg QD + investigator choice of chemotherapy (capecitabine + oxaliplatin [CAPOX] Q3W ×4 or 5-fluorouracil + leucovorin + oxaliplatin [mFOLFOX6] Q2W ×6) and consolidation with pembrolizumab 400 mg Q6W for ≤16 doses + lenvatinib 20 mg QD; dose-limiting toxicities (DLTs), defined as selected prespecified grade ≥3 adverse events (AEs) or any-grade thromboembolic events, were evaluated for 21 days after the first dose of study intervention. If ≥3 DLTs occurred in either oxaliplatin-containing regimen, then enrollment in part 2 may be delayed to allow for the examination of safety data and to consider design changes. In part 1, the primary end point was safety and tolerability in all patients. Preliminary efficacy was also assessed in part 1. Objective response and disease control rate were assessed per RECIST version 1.1 by blinded independent central review. Results: In part 1, 15 pts received ≥1 dose of lenvatinib + pembrolizumab + chemotherapy. 1 DLT of grade 3 asthenia occurred in the CAPOX cohort and 1 DLT of grade 4 neutropenia occurred in the FOLFOX cohort. Median time from first dose to data cutoff (Oct 13, 2021) was 7 mo (range, 7-9). Treatment-related AEs occurred in 14 patients (93%), with grade 3/4 events in 8 patients (53%). 4 patients (27%) discontinued any drug because of a treatment-related AE, and no patient discontinued all drugs because of a treatment-related AE. No patients died because of a treatment-related AE. No grade ≥3 immune-mediated AEs or infusion reactions occurred. Objective response was reported in 11 of 15 patients (73%; 95% CI, 45-92) who received ≥1 dose of treatment. Disease control rate was reported in 14 of 15 patients (93%; 95% CI, 68-100) who received ≥1 dose of treatment. Conclusions: In the safety run-in of LEAP-015, lenvatinib + pembrolizumab + chemotherapy was associated with a manageable safety profile in the first-line treatment of advanced/metastatic gastroesophageal adenocarcinoma. Preliminary antitumor activity was observed for lenvatinib + pembrolizumab + chemotherapy. Part 2 will evaluate the efficacy and safety of lenvatinib + pembrolizumab + chemotherapy versus chemotherapy in this same patient population and patient accrual is ongoing. Clinical trial information: NCT04662710 .

Event-free survival as a surrogate for overall survival in gastric and gastroesophageal junction adenocarcinoma: A meta-analysis in the neoadjuvant ±adjuvant setting

PURPOSE

This study assessed the trial-level association between event-free survival (EFS) and overall survival (OS) in gastric or gastroesophageal junction (GEJ) adenocarcinoma in the neoadjuvant ± adjuvant settings.

EXPERIMENTAL DESIGN

A systematic literature review was conducted to identify randomized controlled trials (RCTs) that evaluated neoadjuvant therapies with or without adjuvant therapies for gastric or GEJ adenocarcinoma. A meta-analysis was performed using weighted linear regressions of the treatment effect of OS on the treatment effect of EFS. The coefficient of determination (R²) and associated 95% confidence interval (CI) were used to evaluate the association between treatment effects of EFS and OS. The threshold used for defining good trial-level surrogacy was a correlation coefficient (R) of 0.8 or R² of 0.65, based on prior literature. Sensitivity analyses were performed to assess the robustness of the association with divergent study designs, including study population, inclusion of adjuvant therapy, and definitions of EFS and OS.

RESULTS

The main analysis included 16 comparisons from 15 RCTs. The log(hazard ratio [HR]) of EFS was a significant predictor of log(HR) of OS, with an estimated coefficient of 0.72 (p<0.001) and R²=0.75 (95% CI: 0.49, 0.95), indicating that EFS was a good surrogate outcome for OS. The results of the sensitivity analyses were consistent with the primary results, with R² ranging from 0.76 to 0.89.

CONCLUSION/DISCUSSION

This study suggests that EFS is a good surrogate for OS in gastric or GEJ adenocarcinoma in the neoadjuvant ± adjuvant setting.

T cell-inflamed gene expression profile and PD-L1 expression and pembrolizumab efficacy in advanced esophageal cancer

Aim: Investigate the relationship between response to pembrolizumab and expression of the 18-gene T cell-inflamed gene expression profile (TcellinfGEP) or PD-L1 combined positive score (CPS) in esophageal cancer. Materials & methods: This analysis included heavily pretreated patients with advanced/metastatic esophageal/gastroesophageal junction adenocarcinoma or squamous cell carcinoma who received pembrolizumab in the single-arm, phase II study KEYNOTE-180. PD-L1 CPS was evaluated with PD-L1 IHC 22C3 pharmDx. Results: In patients with squamous cell carcinoma, trends toward enrichment for responders were observed for patients with PD-L1 CPS ≥10 tumors. In patients with adenocarcinoma, a trend was observed for TcellinfGEP but not for PD-L1. Conclusion: TcellinfGEP and PD-L1 CPS may enrich for responders to pembrolizumab in patients with esophageal cancer. Clinical trial registration: NCT02559687 (ClinicalTrials.gov).

Association of Tumor Mutational Burden with Efficacy of Pembrolizumab{plus minus}Chemotherapy as First-Line Therapy for Gastric Cancer in the Phase III KEYNOTE-062 Study

PURPOSE

This prespecified exploratory analysis evaluated the association between tumor mutational burden (TMB) status and outcomes of first-line pembrolizumab{plus minus}chemotherapy versus chemotherapy in KEYNOTE-062.

EXPERIMENTAL DESIGN

In patients with advanced gastric cancer and evaluable TMB data, we evaluated the association between TMB (continuous variable; square root scale) assessed with FoundationOne® CDx and clinical outcomes [ORR, PFS, and OS] using logistic (ORR) and Cox proportional hazards (PFS, OS) regression models. Clinical utility of TMB was assessed using the prespecified cutoff of 10mut/Mb.

RESULTS

TMB data were available for 306 of 763 patients (40.1%; pembrolizumab, 107; pembrolizumab+chemotherapy, 100; chemotherapy, 99). TMB was significantly associated with clinical outcomes in patients treated with pembrolizumab and pembrolizumab+chemotherapy (ORR, PFS, and OS; all P<0.05) but not with chemotherapy (all P>0.05). The overall prevalence of TMB {greater than or equal to}10mut/Mb was 16% across treatment groups; 44% of patients who had TMB {greater than or equal to}10mut/Mb had high microsatellite instability (MSI-H) tumors. Improved clinical outcomes (ORR, PFS, and OS) were observed in pembrolizumab-treated patients (pembrolizumab monotherapy and pembrolizumab+chemotherapy) with TMB {greater than or equal to}10mut/Mb. When the analysis was limited to the non-MSI-H subgroup, both the positive association between clinical outcomes with pembrolizumab or pembrolizumab+chemotherapy and TMB as a continuous variable and the clinical utility of pembrolizumab (with or without chemotherapy) versus chemotherapy by TMB cutoff were attenuated.

CONCLUSIONS

This exploratory analysis of KEYNOTE-062 suggests an association between TMB and clinical efficacy with first-line pembrolizumab-based therapy in patients with advanced gastric/gastroesophageal junction adenocarcinoma. However, after the exclusion of patients with MSI-H tumors, the clinical utility of TMB was attenuated.

First-line lenvatinib plus pembrolizumab plus chemotherapy in esophageal squamous cell carcinoma: LEAP-014 trial in progress

TPS4167

Background: Recent data from the KEYNOTE-590 study demonstrated the superiority of pembrolizumab plus chemotherapy compared with chemotherapy as first-line treatment for unresectable locally advanced recurrent or metastatic adenocarcinoma or squamous cell carcinoma of the esophagus, or advanced/metastatic Siewert type 1 adenocarcinoma of the gastroesophageal junction. Prior data also suggest promising antitumor activity of lenvatinib plus pembrolizumab in advanced solid tumors. LEAP-014 (NCT04949256) is a randomized, 2-part, open-label, phase 3 study that will evaluate the efficacy and safety of first-line lenvatinib plus pembrolizumab plus chemotherapy versus pembrolizumab plus chemotherapy in patients with metastatic esophageal squamous cell carcinoma (ESCC). Methods: Key eligibility criteria include histologically or cytologically confirmed metastatic ESCC, measurable disease per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1), and Eastern Cooperative Oncology Group performance status 0 to 1. In part 1 (safety run-in), ̃6 patients will be treated for induction with intravenous (IV) pembrolizumab 400 mg every 6 weeks (Q6W) for 2 cycles plus oral lenvatinib 8 mg daily (QD) plus IV 5-fluorouracil (FU; 4000 mg/m2 on days 1-5) plus IV cisplatin (80 mg/m2) (FP) for 4 cycles and treated for consolidation with pembrolizumab 400 mg Q6W for ≤16 doses plus lenvatinib 20 mg QD; patients will be closely monitored for 21 days after the first dose of study intervention for dose-limiting toxicities. In part 2 (main study), approximately 850 patients will be randomly assigned 1:1 to induction with pembrolizumab plus lenvatinib plus chemotherapy (FP or mFOLFOX6 [Q2W for 6 cycles {IV oxaliplatin 85 mg/m2 plus bolus IV 5-FU 400 mg/m2 plus continuous IV 5-FU 2400 mg/m2 plus IV leucovorin 400 mg/m2 or IV levoleucovorin 200 mg/m2}]) followed by consolidation with pembrolizumab plus lenvatinib (arm 1) or pembrolizumab plus chemotherapy (FP or mFOLFOX6; arm 2). Randomization will be stratified by PD-L1 combined positive score (CPS; ≥10 vs < 10), region (East Asia vs North America and Western Europe vs rest of world), and chemotherapy backbone (FP vs mFOLFOX6). Treatment will continue until disease progression, unacceptable toxicity, or withdrawal of consent. Tumor imaging assessment will be performed Q6W for ≤1 year and Q9W thereafter. In part 1, the primary end point is safety and tolerability. In part 2, the dual primary end points are overall survival and progression-free survival (per RECIST v1.1 assessed by blinded independent central review [BICR]); secondary end points include objective response rate and duration of response (per RECIST v1.1 assessed by BICR) and safety and tolerability. Enrollment in this trial is ongoing. Clinical trial information: NCT04949256.

Pembrolizumab with or without chemotherapy versus chemotherapy alone for patients with PD-L1–positive advanced gastric or gastroesophageal junction adenocarcinoma: Update from the phase 3 KEYNOTE-062 trial

243

Background: KEYNOTE-062 (NCT02494583) is a global phase 3 study of pembrolizumab (pembro) as monotherapy and in combination with chemotherapy (chemo) versus chemo as first-line therapy for PD-L1–positive (combined positive score [CPS] ≥1) advanced gastric or gastroesophageal junction (GEJ) adenocarcinoma. At the time of the protocol-specified final analysis, pembro was noninferior to chemo, with fewer adverse events (AEs) observed. Pembro or pembro + chemo was not superior to chemo for the overall survival (OS) and progression-free survival (PFS) end points tested. We present the results of KEYNOTE-062 after ̃25 additional months of follow-up (cutoff: April 19, 2021). Methods: Patients with previously untreated gastric or GEJ cancer were randomly assigned 1:1:1 to pembro 200 mg Q3W, pembro + chemo (cisplatin 80 mg/m2/day on day 1 + 5-FU 800 mg/m2/day on days 1-5 Q3W [or capecitabine 1000 mg/m2 twice daily on days 1-14 Q3W per local guidelines]), or placebo Q3W + chemo. Primary end points were OS in the CPS ≥1 and CPS ≥10 populations for pembro + chemo versus chemo and pembro versus chemo and PFS (RECIST v1.1; central review) in the CPS ≥1 and CPS ≥10 populations for pembro + chemo versus chemo. Safety was also evaluated. Results: At the time of data cutoff, 689 of 763 patients (90.3%) had died. Median follow-up (defined as time from randomization to data cutoff) was 54.3 months (range, 46.8-66.1). Pembro was noninferior to chemo for OS in the CPS ≥1 population (median, 10.6 vs 11.1 months; HR, 0.90; 95% CI, 0.75-1.08) but had a clinically meaningful OS benefit in the CPS ≥10 population (median, 17.4 vs 10.8 months; HR, 0.62; 95% CI, 0.45-0.86). 24-month OS rates (pembro vs chemo) were 26.6% versus 18.8% in the CPS ≥1 population and 39.1% versus 21.1% in the CPS ≥10 population. Pembro + chemo was not superior to chemo for OS in the CPS ≥1 (median, 12.5 vs 11.1 months; HR, 0.85; 95% CI, 0.71-1.02) or the CPS ≥10 (median, 12.3 vs 10.8 months; HR, 0.76; 95% CI, 0.56-1.03) population. 24-month OS rates (pembro + chemo vs chemo) were 24.5% versus 18.8% in the CPS ≥1 population and 28.3% versus 21.1% in the CPS ≥10 population. Pembro + chemo did not significantly prolong PFS versus chemo in the CPS ≥1 (median, 6.9 vs 6.5 months; HR, 0.84; 95% CI, 0.70-1.01) or the CPS ≥10 (median, 5.8 vs 6.2 months; HR, 0.71; 95% CI, 0.52-0.96) population. Grade 3-5 treatment-related AEs rates were 17.3% (pembro), 73.2% (pembro + chemo), and 69.3% (chemo). Conclusions: After ̃25 additional months of follow-up, efficacy and safety outcomes with first-line pembro or pembro + chemo versus chemo in patients with gastric or GEJ adenocarcinoma enrolled in KEYNOTE-062 were consistent with the final analysis data. Clinical trial information: NCT02494583.

LEAP-014: An open-label, randomized, phase 3 study of first-line lenvatinib plus pembrolizumab plus chemotherapy in esophageal squamous cell carcinoma

TPS367

Background: Recent data from the KEYNOTE-590 study demonstrated the superiority of pembrolizumab plus chemotherapy compared with chemotherapy as first-line treatment for unresectable locally advanced recurrent or metastatic adenocarcinoma or squamous cell carcinoma of the esophagus, or advanced/metastatic Siewert type 1 adenocarcinoma of the gastroesophageal junction. Prior data also suggest promising antitumor activity of lenvatinib plus pembrolizumab in advanced solid tumors. LEAP-014 (NCT04949256) is a randomized, 2-part, open-label, phase 3 study that will evaluate the efficacy and safety of first-line lenvatinib plus pembrolizumab plus chemotherapy versus pembrolizumab plus chemotherapy in patients with metastatic esophageal squamous cell carcinoma (ESCC). Methods: Key eligibility criteria include metastatic ESCC, measurable disease per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1), and Eastern Cooperative Oncology Group performance status ≤1. In part 1 (safety run-in), ̃6 patients will be treated for induction with intravenous (IV) pembrolizumab 400 mg every 6 weeks (Q6W) for 2 cycles plus oral lenvatinib 8 mg daily (QD) plus IV 5-fluorouracil (FU; 4000 mg/m2 on days 1-5) plus IV cisplatin (80 mg/m2) (FP) for 4 cycles and treated for consolidation with pembrolizumab 400 mg Q6W for ≤16 doses plus lenvatinib 20 mg QD; patients will be closely monitored for 21 days after the first dose of study intervention for dose-limiting toxicities. Approximately 850 patients will be randomly assigned 1:1 to induction with pembrolizumab plus lenvatinib plus chemotherapy (FP or mFOLFOX6 [Q2W for 6 cycles {IV oxaliplatin 85 mg/m2 plus bolus IV 5-FU 400 mg/m2 plus continuous IV 5-FU 2400 mg/m2 plus IV leucovorin 400 mg/m2 or IV levoleucovorin 200 mg/m2}]) followed by consolidation with pembrolizumab plus lenvatinib (arm 1) or pembrolizumab plus chemotherapy (FP or mFOLFOX6; arm 2). Randomization will be stratified by PD-L1 combined positive score (CPS; ≥10 vs < 10), region (East Asia vs North America and Western Europe vs rest of world), and chemotherapy backbone (FP vs mFOLFOX6). Treatment will continue until disease progression, unacceptable toxicity, or withdrawal of consent. Tumor imaging assessment will be performed Q6W for ≤1 year and Q9W thereafter. In part 1, the primary end point is safety and tolerability. In part 2, the dual primary end points are overall survival and progression-free survival (per RECIST v1.1 assessed by blinded independent central review [BICR]); secondary end points include objective response rate and duration of response (per RECIST v1.1 assessed by BICR) and safety and tolerability. Clinical trial information: NCT04949256.

First-line pembrolizumab plus chemotherapy versus chemotherapy in advanced esophageal cancer: Longer-term efficacy, safety, and quality-of-life results from the phase 3 KEYNOTE-590 study

241

Background: At interim analysis of the phase 3, randomized, double-blind KEYNOTE-590 (NCT03189719) study, 1L pembrolizumab (pembro) + chemotherapy (chemo) vs chemo alone provided superior OS, PFS, and ORR with a manageable safety profile in patients (pts) with untreated, advanced/unresectable or metastatic adenocarcinoma or esophageal squamous cell carcinoma (ESCC) or Siewert type 1 esophagogastric junction adenocarcinoma (EGJ). We report efficacy, safety, and health-related quality of life (HRQoL) results with an additional 12 months (mo) of follow-up. Methods: 749 eligible pts were randomized 1:1 to pembro 200 mg or placebo Q3W for up to 2 yr + chemo. Randomization was stratified by geographic region, histology, and performance status. Treatment continued until progression, unacceptable toxicity, or withdrawal, or 2 yr. No crossover was permitted. Primary endpoints were OS in pts with ESCC PD-L1 combined positive score (CPS) ≥10 tumors, and OS and PFS (RECIST v1.1; by INV) in ESCC, PD-L1 CPS ≥10, and all pts. Secondary endpoints included ORR, DOR, safety, and HRQoL. HRQol was assessed in 711 treated pts with ≥1 HRQoL assessment (356 pembro + chemo; 355 chemo). Data cutoff was July 9, 2021. Results: At data cutoff, median follow-up (randomization to data cutoff) was 34.8 mo. Median OS was longer with pembro + chemo vs chemo in pts with ESCC CPS ≥10 (HR 0.59; 95% CI, 0.45-0.76), ESCC (HR 0.73; 95% CI, 0.61-0.88), CPS ≥10 (HR 0.64; 95% CI, 0.51-0.80), and all pts (HR 0.73, 95% CI, 0.63-0.86). In pts with adenocarcinoma OS HR was 0.73 (95% CI, 0.55-0.99). The 24-mo OS rate in all pts was 26.3% vs 16.1%. Median PFS was longer with pembro + chemo vs chemo in ESCC (HR 0.65; 95% CI, 0.54-0.78), CPS ≥10 (HR 0.51; 95% CI, 0.41-0.65), and all pts (HR 0.64; 95% CI, 0.55-0.75). The 24-mo PFS rate in all pts was 11.6% vs 3.3%. Confirmed ORR was 45.0% (25 CR [6.7%]) vs 29.3% (9 CR [2.4%]), with median DOR of 8.3 vs 6.0 mo. Approximately 20% vs 6% of pts had response duration ≥24 months. Grade 3-5 drug-related AE rates were 72% vs 68%. Discontinuation rates from drug-related AEs were 21% vs 12%. There was no significant difference in least square mean (LSM) change from baseline to wk 18 between arms in EORTC QLQ-C30 global health status/quality-of-life (LSM difference -0.10; 95% CI, -3.40-3.20). LSM change from baseline to wk 18 was better with pembro + chemo vs chemo for QLQ-OES 18 pain (-2.94; 95% CI, -5.86 to -0.02) and dysphagia (-5.54; 95% CI, -10.92 to -0.16). Conclusions: With an additional 12 months of follow-up, pembro + chemo continued to provide significant and clinically meaningful improvement in OS, PFS, and ORR vs chemo with a manageable safety profile, and stable quality-of-life for pts with untreated, advanced esophageal and EGJ cancer. These data continue to support 1L pembro + chemo as a new standard of care in these patients. Clinical trial information: NCT03189719.

A randomized phase 3 study evaluating the efficacy and safety of first-line pembrolizumab plus lenvatinib plus chemotherapy versus chemotherapy in patients with advanced/metastatic gastroesophageal adenocarcinoma: LEAP-015

TPS369

Background: PD-1 inhibitor pembrolizumab in combination with the RTK inhibitor lenvatinib has demonstrated antitumor activity and acceptable safety in advanced gastroesophageal adenocarcinoma. Pembrolizumab + lenvatinib + platinum-doublet chemotherapy also showed acceptable safety in metastatic NSCLC in the phase 3 LEAP-006 study. LEAP-015 (NCT04662710) is a randomized, 2-part, phase 3 trial evaluating the efficacy and safety of pembrolizumab + lenvatinib + chemotherapy as first-line therapy in advanced/metastatic gastroesophageal adenocarcinoma. Methods: Key eligibility includes untreated locally advanced unresectable or metastatic gastroesophageal adenocarcinoma that is not HER2–positive, measurable disease per RECIST v1.1, ECOG performance status ≤1, and a tumor tissue sample for biomarker analysis. For part 1, safety run-in, ≥12 patients will be treated for induction with IV pembrolizumab 400 mg Q6W (×2) + oral lenvatinib 8 mg QD + investigator’s choice of chemotherapy (CAPOX Q3W ×4 [oral capecitabine 1000 mg/m2 BID for 14 days + IV oxaliplatin 130 mg/m2] or mFOLFOX6 Q2W ×6 [bolus IV 5-FU 400 mg/m2 + continuous IV 5-FU 2400 mg/m2 + IV leucovorin 400 mg/m2 or levoleucovorin 200 mg/m2 + IV oxaliplatin 85 mg/m2 ]) and for consolidation with pembrolizumab 400 mg Q6W for ≤16 doses + lenvatinib 20 mg QD; dose-limiting toxicities will be evaluated for 21 days. For part 2, main study, patients will be randomly assigned 1:1 to induction with pembrolizumab + lenvatinib + chemotherapy (CAPOX or mFOLFOX6) followed by consolidation with pembrolizumab + lenvatinib using the same dosing schedule as in part 1 or chemotherapy alone (CAPOX or mFOLFOX6 for maximum cycles allowed per local standards). Randomization will be stratified by region (East Asia vs North America and Western Europe vs rest of world), ECOG performance status (0 vs 1), and intended chemotherapy (CAPOX vs mFOLFOX6). Treatment will continue until confirmed disease progression, unacceptable toxicity, intercurrent illness that prevents further administration of treatment, patient/physician decision to withdraw, noncompliance, receipt of 18 administrations of study medication, achievement of complete response, or administrative reasons requiring cessation of treatment. Tumor imaging assessment will be performed Q6W. In part 1, the primary end point is safety and tolerability in all patients. In part 2, dual primary end points are OS and PFS (per RECIST v1.1 assessed by BICR) in patients with PD-L1 combined positive score (CPS) ≥1 and in all patients; secondary end points include objective response rate and duration of response (per RECIST v1.1 assessed by BICR) in patients with PD-L1 CPS ≥1 and in all patients, and safety and tolerability in all patients. Recruitment is ongoing. Clinical trial information: NCT04662710.

Pembrolizumab versus paclitaxel for previously treated PD-L1-positive advanced gastric or gastroesophageal junction cancer: 2-year update of the randomized phase 3 KEYNOTE-061 trial

BACKGROUND

In the phase 3 KEYNOTE-061 study (cutoff: 10/26/2017), pembrolizumab did not significantly prolong OS vs paclitaxel as second-line (2L) therapy in PD-L1 combined positive score (CPS) ≥ 1 gastric/GEJ cancer. We present results in CPS ≥ 1, ≥ 5, and ≥ 10 populations after two additional years of follow-up (cutoff: 10/07/2019).

METHODS

Patients were randomly allocated 1:1 to pembrolizumab 200 mg Q3W for ≤ 35 cycles or standard-dose paclitaxel. Primary endpoints: OS and PFS (CPS ≥ 1 population). HRs were calculated using stratified Cox proportional hazards models.

RESULTS

366/395 patients (92.7%) with CPS ≥ 1 died. Pembrolizumab demonstrated a trend toward improved OS vs paclitaxel in the CPS ≥ 1 population (HR, 0.81); 24-month OS rates: 19.9% vs 8.5%. Pembrolizumab incrementally increased the OS benefit with PD-L1 enrichment (CPS ≥ 5: HR, 0.72, 24-month rate, 24.2% vs 8.8%; CPS ≥ 10: 0.69, 24-month rate, 32.1% vs 10.9%). There was no difference in median PFS among treatment groups (CPS ≥ 1: HR, 1.25; CPS ≥ 5: 0.98; CPS ≥ 10: 0.79). ORR (pembrolizumab vs paclitaxel) was 16.3% vs 13.6% (CPS ≥ 1), 20.0% vs 14.3% (CPS ≥ 5), and 24.5% vs 9.1% (CPS ≥ 10); median DOR was 19.1 months vs 5.2, 32.7 vs 4.8, and NR vs 6.9, respectively. Fewer treatment-related AEs (TRAEs) occurred with pembrolizumab than paclitaxel (53% vs 84%).

CONCLUSION

In this long-term analysis, 2L pembrolizumab did not significantly improve OS but was associated with higher 24-month OS rates than paclitaxel. Pembrolizumab also increased OS benefit with PD-L1 enrichment among patients with PD-L1-positive gastric/GEJ cancer and led to fewer TRAEs than paclitaxel.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02370498.

Second-line pembrolizumab versus chemotherapy in Japanese patients with advanced esophageal cancer: subgroup analysis from KEYNOTE-181

BACKGROUND

Safe and effective treatments for advanced esophageal cancer are an unmet need in Japan. We report results of a subgroup analysis of Japanese patients enrolled in KEYNOTE-181, a randomized, open-label, phase 3 study of pembrolizumab versus chemotherapy as second-line therapy for patients with advanced or metastatic esophageal cancer whose disease progressed after standard first-line therapy.

METHODS

Patients were randomly assigned 1:1 to receive pembrolizumab 200 mg every 3 weeks or investigator's choice of paclitaxel, docetaxel, or irinotecan. Efficacy was evaluated in all Japanese patients and in those with programmed death ligand 1 combined positive score ≥ 10.

RESULTS

Of the 152 Japanese patients enrolled (pembrolizumab, n = 77; chemotherapy, n = 75), 150 (98.7%) had squamous cell carcinoma and 79 (52.0%) had combined positive score ≥ 10. At the final analysis, median overall survival was improved among all patients (12.4 vs 8.2 months with pembrolizumab and chemotherapy, respectively; hazard ratio, 0.68; 95% CI 0.48-0.97) and patients with combined positive score ≥ 10 (12.6 vs 8.4 months; hazard ratio, 0.68; 95% CI 0.42-1.10). Fewer patients had any-grade (74.0% vs 95.9%) or grade 3-5 (16.9 vs 50.0%) treatment-related adverse events with pembrolizumab than with chemotherapy.

CONCLUSION

Consistent with the global trial results, second-line pembrolizumab therapy showed a survival benefit and a favorable safety profile compared with chemotherapy in Japanese patients with advanced esophageal cancer.

Impact of Pembrolizumab Versus Chemotherapy as Second-Line Therapy for Advanced Esophageal Cancer on Health-Related Quality of Life in KEYNOTE-181

PURPOSE

In the phase III KEYNOTE-181 study (NCT02564263) of patients with advanced esophageal cancer (EC), pembrolizumab monotherapy prolonged overall survival versus chemotherapy as second-line therapy in patients with programmed death ligand 1 combined positive score (CPS) ≥ 10. We present the results of the prespecified health-related quality-of-life (HRQoL) analyses of the squamous cell carcinoma (SCC), CPS ≥ 10, and CPS ≥ 10 SCC populations.

PATIENTS AND METHODS

HRQoL was measured using the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 (QLQ-C30), EORTC QLQ EC questionnaire (OES18), and EuroQol 5-dimension questionnaire (EQ-5D). Data were analyzed in patients who received ≥ 1 dose of study treatment and completed ≥ 1 HRQoL assessment. Key analyses included baseline to week 9 least squares mean change in global health status/quality of life, functional or symptom subscales, and time to deterioration (≥ 10-point deterioration) for specific subscales.

RESULTS

The HRQoL population included 387 patients with SCC. Compliance and completion rates for all three questionnaires were similar in both treatment groups at baseline and week 9. No clinically meaningful differences in global health status/quality of life scores were observed between treatment groups from baseline to week 9 (least squares mean difference, 2.80; 95% CI, -1.48 to 7.08); patients in both treatment groups generally exhibited stable functioning and symptom scores of the QLQ-C30 and QLQ-OES18 from baseline to week 9. Time to deterioration for pain (hazard ratio [HR], 1.22; 95% CI, 0.79 to 1.89), reflux (HR, 2.38; 95% CI, 1.33 to 4.25), and dysphagia (HR, 1.53; 95% CI, 1.02 to 2.31) subscales were similar between treatment groups. These findings were generally similar in the CPS ≥ 10 (n = 218) and CPS ≥ 10 SCC (n = 166) subgroups.

CONCLUSION

In patients with advanced EC, pembrolizumab monotherapy and chemotherapy maintained HRQoL in patients with SCC, CPS ≥ 10, and CPS ≥ 10 SCC.

Pembrolizumab plus chemotherapy versus chemotherapy alone for first-line treatment of advanced oesophageal cancer (KEYNOTE-590): a randomised, placebo-controlled, phase 3 study

BACKGROUND

First-line therapy for advanced oesophageal cancer is currently limited to fluoropyrimidine plus platinum-based chemotherapy. We aimed to evaluate the antitumour activity of pembrolizumab plus chemotherapy versus chemotherapy alone as first-line treatment in advanced oesophageal cancer and Siewert type 1 gastro-oesophageal junction cancer.

METHODS

We did a randomised, placebo-controlled, double-blind, phase 3 study across 168 medical centres in 26 countries. Patients aged 18 years or older with previously untreated, histologically or cytologically confirmed, locally advanced, unresectable or metastatic oesophageal cancer or Siewert type 1 gastro-oesophageal junction cancer (regardless of PD-L1 status), measurable disease per Response Evaluation Criteria in Solid Tumors version 1.1, and Eastern Cooperative Oncology Group performance status of 0-1, were randomly assigned (1:1) to intravenous pembrolizumab 200 mg or placebo, plus 5-fluorouracil and cisplatin (chemotherapy), once every 3 weeks for up to 35 cycles. Randomisation was stratified by geographical region, histology, and performance status. Patients, investigators, and site staff were masked to group assignment and PD-L1 biomarker status. Primary endpoints were overall survival in patients with oesophageal squamous cell carcinoma and PD-L1 combined positive score (CPS) of 10 or more, and overall survival and progression-free survival in patients with oesophageal squamous cell carcinoma, PD-L1 CPS of 10 or more, and in all randomised patients. This trial is registered with ClinicalTrials.gov, NCT03189719, and is closed to recruitment.

FINDINGS

Between July 25, 2017, and June 3, 2019, 1020 patients were screened and 749 were enrolled and randomly assigned to pembrolizumab plus chemotherapy (n=373 [50%]) or placebo plus chemotherapy (n=376 [50%]). At the first interim analysis (median follow-up of 22·6 months), pembrolizumab plus chemotherapy was superior to placebo plus chemotherapy for overall survival in patients with oesophageal squamous cell carcinoma and PD-L1 CPS of 10 or more (median 13·9 months vs 8·8 months; hazard ratio 0·57 [95% CI 0·43-0·75]; p<0·0001), oesophageal squamous cell carcinoma (12·6 months vs 9·8 months; 0·72 [0·60-0·88]; p=0·0006), PD-L1 CPS of 10 or more (13·5 months vs 9·4 months; 0·62 [0·49-0·78]; p<0·0001), and in all randomised patients (12·4 months vs 9·8 months; 0·73 [0·62-0·86]; p<0·0001). Pembrolizumab plus chemotherapy was superior to placebo plus chemotherapy for progression-free survival in patients with oesophageal squamous cell carcinoma (6·3 months vs 5·8 months; 0·65 [0·54-0·78]; p<0·0001), PD-L1 CPS of 10 or more (7·5 months vs 5·5 months; 0·51 [0·41-0·65]; p<0·0001), and in all randomised patients (6·3 months vs 5·8 months; 0·65 [0·55-0·76]; p<0·0001). Treatment-related adverse events of grade 3 or higher occurred in 266 (72%) patients in the pembrolizumab plus chemotherapy group versus 250 (68%) in the placebo plus chemotherapy group.

INTERPRETATION

Compared with placebo plus chemotherapy, pembrolizumab plus chemotherapy improved overall survival in patients with previously untreated, advanced oesophageal squamous cell carcinoma and PD-L1 CPS of 10 or more, and overall survival and progression-free survival in patients with oesophageal squamous cell carcinoma, PD-L1 CPS of 10 or more, and in all randomised patients regardless of histology, and had a manageable safety profile in the total as-treated population.

FUNDING

Merck Sharp & Dohme.

KEYNOTE-859: a Phase III study of pembrolizumab plus chemotherapy in gastric/gastroesophageal junction adenocarcinoma

Current guidelines recommend two-drug cytotoxic chemotherapy with a fluoropyrimidine (fluorouracil or capecitabine) and a platinum-based agent (oxaliplatin or cisplatin) as first-line treatment for advanced gastric cancer. Pembrolizumab monotherapy has demonstrated durable antitumor activity in patients with advanced programmed death ligand 1-positive (combined positive score ≥1) gastric/gastroesophageal junction adenocarcinoma. Accumulating evidence indicates that combining pembrolizumab with standard-of-care chemotherapy for the treatment of advanced or metastatic cancer improves clinical outcomes. We describe the rationale for and the design of the randomized, double-blind, placebo-controlled, Phase III KEYNOTE-859 study, which is investigating pembrolizumab in combination with chemotherapy as first-line treatment for patients with human epidermal growth factor receptor 2-negative advanced unresectable or metastatic gastric/gastroesophageal junction adenocarcinoma. The planned sample size is 1542 patients, and the primary end point is overall survival. Clinical trial registration: NCT03675737 (ClinicalTrials.gov).

Assessment of Pembrolizumab Therapy for the Treatment of Microsatellite Instability-High Gastric or Gastroesophageal Junction Cancer Among Patients in the KEYNOTE-059, KEYNOTE-061, and KEYNOTE-062 Clinical Trials

Importance

Immunotherapy has been associated with improved outcomes among patients who have received previous treatment for microsatellite instability-high (MSI-H) tumors.

Objective

To evaluate the antitumor activity of pembrolizumab therapy vs chemotherapy among patients with MSI-H advanced gastric or gastroesophageal junction (G/GEJ) cancer regardless of the line of therapy in which it was received.

Design, Setting, and Participants

This post hoc analysis of the phase 2 KEYNOTE-059 (third-line treatment or higher) single-arm trial and the phase 3 KEYNOTE-061 (second-line treatment) and KEYNOTE-062 (first-line treatment) randomized trials included patients with advanced G/GEJ cancer from 52 sites in 16 countries enrolled in KEYNOTE-059, 148 sites in 30 countries enrolled in KEYNOTE-061, and 200 sites in 29 countries enrolled in KEYNOTE-062. Patients were enrolled from March 2, 2015, to March 26, 2016, in KEYNOTE-059; from June 4, 2015, to July 26, 2016, in KEYNOTE-061; and from September 18, 2015, to May 26, 2017, in KEYNOTE-062, with data cutoff dates of August 8, 2018; October 26, 2017; and March 26, 2019; respectively.

Interventions

Pembrolizumab monotherapy in KEYNOTE-059, pembrolizumab monotherapy or chemotherapy (paclitaxel) in KEYNOTE-061, and pembrolizumab monotherapy, pembrolizumab plus chemotherapy (cisplatin and 5-fluorouracil or capecitabine), or chemotherapy alone in KEYNOTE-062.

Main Outcomes and Measures

Response was assessed centrally using Response Evaluation Criteria in Solid Tumours (RECIST), version 1.1; MSI-H status was determined centrally by polymerase chain reaction testing.

Results

At data cutoff, 7 of 174 patients (4.0%) in KEYNOTE-059, 27 of 514 patients (5.3%) in KEYNOTE-061, and 50 of 682 patients (7.3%) in KEYNOTE-062 had MSI-H tumors. Among those with MSI-H tumors, the median overall survival was not reached (NR) for pembrolizumab in KEYNOTE-059, KEYNOTE-061, and KEYNOTE-062 or for pembrolizumab plus chemotherapy in KEYNOTE-062. The median progression-free survival (PFS) for pembrolizumab was NR (95% CI, 1.1 months to NR) in KEYNOTE-059 and 17.8 months (95% CI, 2.7 months to NR) in KEYNOTE-061 (vs 3.5 months [95% CI, 2.0-9.8 months] for chemotherapy). In KEYNOTE-062, the median PFS was 11.2 months (95% CI, 1.5 months to NR) for pembrolizumab, NR (95% CI, 3.6 months to NR) for pembrolizumab plus chemotherapy, and 6.6 months (95% CI, 4.4-8.3 months) for chemotherapy. The objective response rate (ORR) for pembrolizumab was 57.1% in KEYNOTE-059 and 46.7% (vs 16.7% for chemotherapy) in KEYNOTE-061. In KEYNOTE-062, the ORR was 57.1% for pembrolizumab , 64.7% for pembrolizumab plus chemotherapy, and 36.8% for chemotherapy.

Conclusions and Relevance

Findings from this study indicate that MSI-H status may be a biomarker for pembrolizumab therapy among patients with advanced G/GEJ cancer regardless of the line of therapy in which it was received.

Trial Registration

ClinicalTrials.gov Identifiers: NCT02335411, NCT02370498, and NCT02494583.

Pembrolizumab plus trastuzumab and chemotherapy for HER2+ metastatic gastric or gastroesophageal junction (G/GEJ) cancer: Initial findings of the global phase 3 KEYNOTE-811 study

4013

Background: Trastuzumab (tras) plus chemotherapy (chemo) is standard-of-care (SOC) 1L therapy for HER2+ metastatic G/GEJ cancer. In two phase 2 studies, tras, chemo, and pembrolizumab (pembro) in combination showed promising efficacy and manageable safety. The ongoing global, randomized, double-blind, placebo-controlled phase 3 KEYNOTE-811 study is assessing whether adding pembro to SOC improves efficacy vs SOC alone for HER2+ metastatic G/GEJ cancer (NCT03615326). Methods: Eligible patients (pts) with previously untreated, unresectable or metastatic HER2+ G/GEJ cancer and ECOG PS 0 or 1 are randomized 1:1 to pembro 200 mg IV Q3W or placebo IV Q3W. All pts receive tras and investigator’s choice of 5-fluorouracil and cisplatin (FP) or capecitabine and oxaliplatin (CAPOX). Treatment is given up to 2 y or until intolerable toxicity or PD. Dual primary end points are PFS per RECIST v1.1 by blinded, independent central review (BICR) and OS. Secondary end points are ORR and DOR per RECIST v1.1 by BICR and safety. Planned enrollment in the global cohort is 692 pts; accrual is almost complete. The protocol-specified first interim analysis (IA1) was to occur when the first 260 pts enrolled had ≥8.5 mo of follow-up and tested whether pembro + SOC significantly improved ORR; the superiority boundary was P = 0.002. The ORR difference was calculated using the Miettinen and Nurminen method stratified by the randomization stratification factors of geographic region, PD-L1 status, and chemo choice. Efficacy is presented for the first 264 pts enrolled. Safety is presented for all treated pts enrolled as of Jun 17, 2020. Results: Among the first 264 pts enrolled, 133 were randomized to pembro + SOC, 131 to placebo + SOC; 0.8% had MSI-H tumors, CAPOX was chosen for 87.1%, and median study follow-up was 12.0 mo (range, 8.5-19.4). Confirmed ORR (95% CI) was 74.4% (66.2-81.6) for pembro + SOC vs 51.9% (43.0-60.7) for placebo + SOC (difference, 22.7 percentage points [95% CI, 11.2-33.7], P = 0.00006); CR rate was 11.3% vs 3.1% and DCR (95% CI) was 96.2% (91.4-98.8) vs 89.3 (82.7-94.0). Median (range) DOR was 10.6 mo (1.1+ to 16.5+) for pembro + SOC vs 9.5 mo (1.4+ to 15.4+) for placebo + SOC; KM estimates of DOR ≥6 mo and ≥9 mo were 70.3% vs 61.4% and 58.4% vs 51.1%. As of data cutoff, 433/434 enrolled pts were treated (217/217 pembro + SOC, 216/217 placebo + SOC). AEs were grade 3-5 in 57.1% of pts with pembro + SOC vs 57.4% with placebo + SOC, led to death in 3.2% vs 4.6%, and led to discontinuation of any drug in 24.4% vs 25.9%. Conclusions: Adding pembro to tras and chemo resulted in a substantial, statistically significant increase in ORR versus trastuzumab and chemo alone as 1L therapy for HER2+ metastatic G/GEJ cancer; responses were durable and safety was manageable. These initial data support pembro plus tras and chemo as a potential new treatment option for this population. Clinical trial information: NCT03615326.

KEYNOTE-975 study design: a Phase III study of definitive chemoradiotherapy plus pembrolizumab in patients with esophageal carcinoma

Despite curative-intent treatment, most patients with locally advanced esophageal cancer will experience disease recurrence or locoregional progression, highlighting the need for new therapies. Current guidelines recommend definitive chemoradiotherapy in patients ineligible for surgical resection, but survival outcomes are poor. Pembrolizumab is well tolerated and provides promising antitumor activity in patients with previously treated, advanced, unresectable esophageal/esophagogastric junction cancer. Combining pembrolizumab with chemoradiotherapy may further improve outcomes in the first-line setting. Here, we describe the design and rationale for the double-blind, Phase III, placebo-controlled, randomized KEYNOTE-975 trial investigating pembrolizumab in combination with definitive chemoradiotherapy as first-line treatment in patients with locally advanced, unresectable esophageal/gastroesophageal junction cancer. Overall survival and event-free survival are the dual primary end points.

Clinical trial registration: NCT04210115 (ClinicalTrials.gov)

Pembrolizumab plus chemotherapy for previously untreated, HER2-negative unresectable or metastatic advanced gastric or gastroesophageal junction (G/GEJ) adenocarcinoma: KEYNOTE-859

TPS263

Background: For patients with unresectable, locally advanced recurrent or metastatic G/GEJ cancer, the standard of care includes a fluoropyrimidine plus a platinum-based agent as first-line therapy. The PD-1 inhibitor pembrolizumab has demonstrated durable antitumor activity in this patient population across lines of therapy. Herein, we describe the randomized, double-blind, phase 3 KEYNOTE-859 trial (NCT03675737) of first-line pembrolizumab plus chemotherapy in patients with advanced G/GEJ adenocarcinoma. Methods: Patients with histologically or cytologically confirmed, locally advanced unresectable or metastatic G/GEJ adenocarcinoma with known PD-L1 expression status, HER2-negative disease, measurable disease per RECIST v1.1, and ECOG performance status of 0 or 1 will be randomly assigned 1:1 to receive pembrolizumab plus chemotherapy or placebo plus chemotherapy. Randomization will be stratified by geographic region (Europe/Israel/North America/Australia vs Asia vs rest of world), PD-L1 tumor expression status (combined positive score < 1 vs ≥1), and combination chemotherapy (FP vs CAPOX). Pembrolizumab or placebo will be administered at 200 mg IV every 3 weeks (Q3W). The chemotherapy regimen will be investigator’s choice of FP (continuous infusion of 5-fluorouracil [800 mg/m2/day on days 1-5 of each cycle] plus IV cisplatin [80 mg/m2] Q3W) or CAPOX (oral capecitabine [1000 mg/m2 twice daily on days 1-14 of each cycle] plus IV oxaliplatin [130 mg/m2 on day 1 of each cycle] Q3W). Duration of cisplatin or oxaliplatin may be capped at 6 cycles per local country guidelines; treatment with 5-fluorouracil or capecitabine may continue per protocol. Treatment with pembrolizumab or placebo will continue for ≤35 administrations (~2 years) or until disease progression, unacceptable toxicity, intercurrent illness that prevents further administration of treatment, investigator decision, or noncompliance. Imaging will be performed at screening and subsequently every 6 weeks until disease progression, start of new anticancer treatment, withdrawal of consent, or death. Adverse events will be monitored throughout the study from the time of randomization to 30 days after the last dose of study treatment (90 days for serious adverse events). The dual primary end points are OS and PFS per RECIST v1.1 as assessed by blinded independent central review (BICR). Secondary end points include ORR and DOR per RECIST v1.1 as assessed by BICR, safety, and tolerability. Enrollment is ongoing. Clinical trial information: NCT03675737.

Randomized Phase III KEYNOTE-181 Study of Pembrolizumab Versus Chemotherapy in Advanced Esophageal Cancer

PURPOSE

Patients with advanced esophageal cancer have a poor prognosis and limited treatment options after first-line chemotherapy.

PATIENTS AND METHODS

In this open-label, phase III study, we randomly assigned (1:1) 628 patients with advanced/metastatic squamous cell carcinoma or adenocarcinoma of the esophagus, that progressed after one prior therapy, to pembrolizumab 200 mg every 3 weeks for up to 2 years or chemotherapy (investigator's choice of paclitaxel, docetaxel, or irinotecan). Primary end points were overall survival (OS) in patients with programmed death ligand-1 (PD-L1) combined positive score (CPS) ≥ 10, in patients with squamous cell carcinoma, and in all patients (one-sided α 0.9%, 0.8%, and 0.8%, respectively).

RESULTS

At final analysis, conducted 16 months after the last patient was randomly assigned, OS was prolonged with pembrolizumab versus chemotherapy for patients with CPS ≥ 10 (median, 9.3 v 6.7 months; hazard ratio [HR], 0.69 [95% CI, 0.52 to 0.93]; P = .0074). Estimated 12-month OS rate was 43% (95% CI, 33.5% to 52.1%) with pembrolizumab versus 20% (95% CI, 13.5% to 28.3%) with chemotherapy. Median OS was 8.2 months versus 7.1 months (HR, 0.78 [95% CI, 0.63 to 0.96]; P = .0095) in patients with squamous cell carcinoma and 7.1 months versus 7.1 months (HR, 0.89 [95% CI, 0.75 to 1.05]; P = .0560) in all patients. Grade 3-5 treatment-related adverse events occurred in 18.2% of patients with pembrolizumab versus 40.9% in those who underwent chemotherapy.

CONCLUSION

Pembrolizumab prolonged OS versus chemotherapy as second-line therapy for advanced esophageal cancer in patients with PD-L1 CPS ≥ 10, with fewer treatment-related adverse events.

First-line pembrolizumab/placebo plus trastuzumab and chemotherapy in HER2-positive advanced gastric cancer: KEYNOTE-811

Treatment options for patients with HER2-positive advanced gastric cancer are limited, and the prognosis for these patients is poor. Pembrolizumab has demonstrated promising antitumor activity in patients with advanced gastric or gastroesophageal junction adenocarcinoma as monotherapy, in combination with chemotherapy and in combination with trastuzumab. Combining pembrolizumab with trastuzumab and chemotherapy may therefore provide a benefit for patients with advanced HER2-positive gastric cancer. Here we aimed to describe the design of and rationale for the randomized, double-blind, placebo-controlled Phase III KEYNOTE-811 study, which will evaluate the efficacy and safety of pembrolizumab or placebo in combination with trastuzumab and chemotherapy as first-line treatment for patients with advanced HER2-positive gastric or gastroesophageal junction adenocarcinoma.

Clinical trial registration: NCT03615326 (ClinicalTrials.gov)

Randomized Phase III KEYNOTE-181 Study of Pembrolizumab Versus Chemotherapy in Advanced Esophageal Cancer

PURPOSE

Patients with advanced esophageal cancer have a poor prognosis and limited treatment options after first-line chemotherapy.

PATIENTS AND METHODS

In this open-label, phase III study, we randomly assigned (1:1) 628 patients with advanced/metastatic squamous cell carcinoma or adenocarcinoma of the esophagus, that progressed after one prior therapy, to pembrolizumab 200 mg every 3 weeks for up to 2 years or chemotherapy (investigator's choice of paclitaxel, docetaxel, or irinotecan). Primary end points were overall survival (OS) in patients with programmed death ligand-1 (PD-L1) combined positive score (CPS) ≥ 10, in patients with squamous cell carcinoma, and in all patients (one-sided α 0.9%, 0.8%, and 0.8%, respectively).

RESULTS

At final analysis, conducted 16 months after the last patient was randomly assigned, OS was prolonged with pembrolizumab versus chemotherapy for patients with CPS ≥ 10 (median, 9.3 v 6.7 months; hazard ratio [HR], 0.69 [95% CI, 0.52 to 0.93]; P = .0074). Estimated 12-month OS rate was 43% (95% CI, 33.5% to 52.1%) with pembrolizumab versus 20% (95% CI, 13.5% to 28.3%) with chemotherapy. Median OS was 8.2 months versus 7.1 months (HR, 0.78 [95% CI, 0.63 to 0.96]; P = .0095) in patients with squamous cell carcinoma and 7.1 months versus 7.1 months (HR, 0.89 [95% CI, 0.75 to 1.05]; P = .0560) in all patients. Grade 3-5 treatment-related adverse events occurred in 18.2% of patients with pembrolizumab versus 40.9% in those who underwent chemotherapy.

CONCLUSION

Pembrolizumab prolonged OS versus chemotherapy as second-line therapy for advanced esophageal cancer in patients with PD-L1 CPS ≥ 10, with fewer treatment-related adverse events.

Abstract CT282: KEYNOTE-975: A randomized, double-blind, placebo-controlled phase 3 trial of pembrolizumab vs placebo in participants with esophageal carcinoma receiving concurrent definitive chemoradiotherapy

Background: For patients with unresectable esophageal cancer (EC), definitive chemoradiotherapy (dCRT) is a standard treatment option. Platinum plus fluoropyrimidine-based regimens are comparable in dCRT and are considered standard options; however, overall survival (OS) is still poor, indicating a need for more effective therapies. The programmed cell death 1 inhibitor pembrolizumab showed promising response as third- and second-line monotherapy in patients with advanced, unresectable EC in the KEYNOTE-180 and KEYNOTE-181 studies, respectively. In the phase 3 KEYNOTE-181 trial, pembrolizumab extended OS vs chemotherapy in patients with a PD-L1 combined positive score (CPS) ≥10. KEYNOTE-975 is a randomized, multicenter, double-blind, phase 3 study investigating pembrolizumab in combination with dCRT. Methods: Key patient eligibility criteria are age ≥18 years; presence of cTX N+M0 or cT2-T4a NXM0, locally advanced esophageal squamous cell carcinoma (SCC) or adenocarcinoma or Siewert type 1 adenocarcinoma of the esophagogastric junction; ineligible for curative surgery; no previous chemotherapy or radiation for EC; and suitable for dCRT. Patients will be randomly assigned 1:1 to pembrolizumab or placebo added to dCRT, administered as pembrolizumab 200 mg or placebo Q3W for 8 cycles followed by pembrolizumab 400 mg or placebo Q6W for 5 cycles (13 cycles total). The dCRT regimen will be the site's choice of continuous infusion 5-FU + cisplatin (FP) with radiotherapy (RT) 50 Gy, FP with RT 60 Gy, or FOLFOX with RT 50 Gy. Randomization will be stratified by PD-L1 positivity (CPS ≥10 vs CPS &lt;10), RT dose (50 Gy vs 60 Gy), and region/histology (SCC East Asia vs SCC rest of world and adenocarcinoma regardless of region). The primary objectives of KEYNOTE-975 are to compare pembrolizumab and placebo added to dCRT in OS and event-free survival within the prespecified analysis cohorts: patients with CPS ≥10, patients with SCC, and all patients (intention-to-treat population). The secondary objective is to assess the safety and tolerability profile of pembrolizumab vs placebo added to dCRT (adverse events, overall and leading to study drug discontinuation). Exploratory objectives include comparing time to deterioration and change from baseline in quality of life measures, characterizing health utility scores, and identifying molecular biomarkers that may be determinants of response.

Citation Format: Manish A. Shah, Jaafar Bennouna, Toshihiko Doi, Lin Shen, Ken Kato, Antoine Adenis, Harvey Mamon, Markus Moehler, Xiaolong Fu, Byoung Chul Cho, Pooja Bhagia, Chie-Schin Shih, Anjali Desai, Peter Enzinger. KEYNOTE-975: A randomized, double-blind, placebo-controlled phase 3 trial of pembrolizumab vs placebo in participants with esophageal carcinoma receiving concurrent definitive chemoradiotherapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT282.

Pembrolizumab versus paclitaxel for previously treated patients with PD-L1–positive advanced gastric or gastroesophageal junction cancer (GC): Update from the phase III KEYNOTE-061 trial

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Background: KEYNOTE-061 ( NCT02370498) is a global phase 3 study of pembrolizumab vs paclitaxel as second-line therapy for GC. At the time of primary analysis (data cutoff: Oct 26, 2017), in patients with PD-L1–positive status (combined positive score [CPS] ≥1), pembrolizumab did not significantly prolong overall survival (OS) vs paclitaxel (9.1 months vs 8.3 months) but did elicit a longer duration of response (DOR) and a favorable safety profile vs paclitaxel. We present results of KEYNOTE-061 in patients with CPS ≥1, ≥5, and ≥10 after 2 additional years of follow-up (cutoff: Oct 7, 2019). Methods: Adult patients with GC that progressed after platinum + fluoropyrimidine chemotherapy were randomly assigned 1:1 to pembrolizumab 200 mg Q3W for up to 35 cycles (~2 y) or standard-dose paclitaxel. OS and progression-free survival (PFS) in the CPS ≥1 population were the primary end points. Comparisons were made using stratified log-rank tests. Results: At the time of this analysis, 366/395 patients with CPS ≥1 had died (92.6%). Pembrolizumab prolonged OS vs paclitaxel in PD-L1–positive patients (Table). No significant differences appeared between groups in PFS (Table). Objective response rate (ORR) was higher for pembrolizumab in the CPS ≥10 group, and DOR was longer with pembrolizumab using all CPS cutoffs (Table). There were fewer drug-related adverse events (AEs) with pembrolizumab than paclitaxel in the overall population (53% vs 84%). Conclusions: This long-term analysis found that second-line pembrolizumab prolonged OS among patients with PD-L1–positive GC and led to fewer drug-related AEs vs paclitaxel. Clinical trial information: NCT02370498 . [Table: see text]

Pembrolizumab vs paclitaxel as second-line treatment for Asian patients with PD-L1–positive advanced gastric or gastroesophageal cancer (GC) in the phase III KEYNOTE-063 trial

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Background: Approximately 75% of GC cases occur in Asian persons. Pembrolizumab has shown antitumor activity in global studies of GC. KEYNOTE-063 (NCT03019588) is a randomized, open-label, phase 3 trial in Asian patients with advanced PD-L1–positive (combined positive score [CPS] ≥1) GC that progressed after platinum + fluoropyrimidine chemotherapy. After the KEYNOTE-063 study began, results of the global KEYNOTE-061 study (NCT02370498) showed that pembrolizumab did not prolong overall survival (OS) vs paclitaxel in patients previously treated for advanced GC (median OS, 9.1 months vs 8.3 months; hazard ratio [HR], 0.82; 95% CI, 0.66-1.03; 1-sided P= 0.0421 [significance threshold for OS was 1-sided P= 0.0135]). Methods: Eligible patients were randomly assigned in a 1:1 ratio to receive pembrolizumab 200 mg Q3W for up to 35 cycles (~2 years) or standard-dose paclitaxel. The primary efficacy end points were OS and progression-free survival (PFS). Planned enrollment was ~360 patients. Results: Because pembrolizumab did not significantly prolong OS in KEYNOTE-061, enrollment in KEYNOTE-063 was discontinued after 94 patients were enrolled (47 patients in each treatment group). In these Asian patients, median OS was 8.4 months in the pembrolizumab group and 7.7 months in the paclitaxel group; median PFS was 1.9 months and 4.0 months, respectively (Table). Objective response rate (ORR) and median duration of response (DOR) are shown in the Table. Drug-related adverse events (AEs) occurred in 59.6% of patients receiving pembrolizumab and in 95.5% of patients receiving paclitaxel (Table). Conclusions: In this small sample of Asian patients with PD-L1–positive advanced GC, definitive conclusions are limited; however, second-line pembrolizumab monotherapy seems to be well tolerated in this patient population. Because this study was terminated early, there was insufficient power for comparisons between groups; therefore, these data should be viewed with caution. Clinical trial information: NCT03019588 . [Table: see text]

Pembrolizumab (pembro) in microsatellite instability-high (MSI-H) advanced gastric/gastroesophageal junction (G/GEJ) cancer by line of therapy

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Background: Pembro has demonstrated promising antitumor activity in patients (pts) with advanced G/GEJ cancer with PD-L1 CPS ≥1 and CPS ≥10 irrespective of MSI-H status. Here, we examine the antitumor activity of pembro monotherapy vs chemo in pts with MSI-H, advanced G/GEJ cancer in KEYNOTE (KN)-059 (NCT02335411), KN061 (NCT02370498), and KN062 (NCT02494583). Methods: Eligible pts with advanced G/GEJ cancer with ≥2 prior therapies (KN059 cohort 1; 3L+), 1 prior therapy (KN061; 2L), or no prior therapy (KN062; 1L) were enrolled. In KN059 cohort 1, pts received pembro only. In KN061 pts were randomized to pembro or paclitaxel (chemo), and in KN062 to pembro, pembro + cisplatin+5-FU/cape (chemo), or chemo. Pts received pembro 200 mg Q3W for up to 2 y. MSI-H status was determined centrally by PCR. Endpoints included OS, PFS, ORR, and safety. Data cutoff dates were Aug 8, 2018 (KN059), Oct 26, 2017 (KN061), and Mar 26, 2019 (KN062). Results: At data cutoff, 259 pts (n = 7 [3%] MSI-H) had enrolled in KN059 cohort 1 (3L+), 592 (27 [5%] MSI-H]) in KN061 (2L), and 763 (50 [7%] MSI-H] in KN062 (1L). Median follow-up was 5.6 mo, 7.9 mo, and 11.3 mo, respectively. For the overall study populations, median OS was 5.5 mo for pembro (3L+), 6.7 mo vs 8.3 mo for pembro vs chemo (2L), and 10.6 mo vs 11.0 mo for pembro vs chemo (1L). Median PFS was 2.0 mo (3L+), 1.5 vs 4.1 mo (2L), and 2.0 vs 6.4 mo (1L). ORR was 11.6% (3L+), 11.1% vs 12.5% (2L), and 14.8% vs 37.2% (1L), with median DOR of 16.1 mo, 18.0 vs 5.5 mo, and 13.7 vs 6.8 mo. In pts with MSI-H tumors, OS and PFS were prolonged with pembro vs chemo, with higher ORR (Table). Conclusions: As with PD-L1 expressers, MSI-H status is a predictive biomarker for pembro monotherapy in advanced G/GEJ cancer irrespective of line of therapy. Clinical trial information: (KN)-059 (NCT02335411), KN061 (NCT02370498), and KN062 (NCT02494583). Merck & Co., Inc., Kenilworth, NJ, USA.[Table: see text]

Efficacy of pembrolizumab (pembro) monotherapy versus chemotherapy for PD-L1–positive (CPS ≥10) advanced G/GEJ cancer in the phase II KEYNOTE-059 (cohort 1) and phase III KEYNOTE-061 and KEYNOTE-062 studies

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Background: Pts with advanced gastric/gastroesophageal junction (G/GEJ) cancer received pembro monotherapy (200 mg Q3W) 3L+ in cohort 1 of KEYNOTE-059 (NCT02335411), 2L in KEYNOTE-061 (NCT02370498), or 1L in KEYNOTE-062 (NCT02494583). We present efficacy data for patients with PD-L1 combined positive score (CPS) ≥10 tumors in these trials. Methods: In study 059, 46 pts in cohort 1 with PD-L1 CPS ≥10 received pembro. In study 061, 108 pts with PD-L1 CPS ≥10 received pembro (n=53) or chemotherapy (chemo; n=55). In study 062, 182 pts with CPS ≥10 received pembro (n=92) or placebo + chemo (n=90). Efficacy end points included overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and duration of response (DOR). Results: Median follow-up in study 059 was 5.6 mo. Median OS with pembro was 7.9 mo (95% CI, 5.8-11.1), and 12-mo OS was 32.6%. PFS at 6 mo was 17.4%, ORR was 17.4%, and median DOR was 20.9 mo (2.8+ to 34.9+). In study 061, after a median follow-up of 8.8 mo, pembro prolonged OS vs chemo (median 10.4 vs 8.0 mo; HR, 0.64; 95% CI, 0.41-1.02); 12-mo OS was 45.3% for pembro and 23.6% for chemo. Median PFS was 2.7 mo for pembro and 3.4 mo for chemo (HR, 0.86; 95% CI, 0.56-1.33). ORR was 24.5% vs 9.1%, and median DOR was NR (4.1-26.0+) and 6.9 mo (2.6-6.9) for pembro vs chemo. In study 062, median follow-up was 17.4 mo for pembro and 10.8 mo for chemo. Pembro prolonged OS vs chemo (median 17.4 vs 10.8 mo; HR, 0.69; 95% CI, 0.49-0.97); 12-mo OS was 56.5% vs 46.7%. Median PFS was 2.9 mo vs 6.1 mo (HR, 1.09, 95% CI, 0.79-1.49). ORR was 25.0% vs 37.8%, and median DOR was 19.3 mo (1.4+ to 33.6+) vs 6.8 mo (1.5+ to 30.4+) for pembro vs chemo, respectively. Conclusions: Collectively, these data indicate that 1L, 2L, and 3L+ pembro monotherapy showed clinically meaningful efficacy in CPS ≥10, with a more durable response than chemotherapy. Clinical trial information: NCT02335411, NCT02370498, and NCT02494583.

[Table: see text]

KEYNOTE-811 pembrolizumab plus trastuzumab and chemotherapy for HER2+ metastatic gastric or gastroesophageal junction cancer (mG/GEJc): A double-blind, randomized, placebo-controlled phase III study

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Background: Combination therapy with the anti-HER2 antibody trastuzumab plus fluoropyrimidine and platinum is the current standard of care for patients with HER2+ mG/GEJc. We hypothesize that combination anti–PD-1 and anti-HER2 therapy will result in T-cell activation, augment antibody-dependent, cell-mediated cytotoxicity, and potentiate antitumor immune response in HER2+ patients. A phase 2 study in HER2+ mG/GEJc demonstrated the safety and preliminary efficacy of trastuzumab/pembrolizumab/chemotherapy; the objective response rate was 87%, and the disease control rate was 100% (Janjigian YY, ASCO GI 2019). KEYNOTE-811 (ClinicalTrials.gov, NCT03615326), a global, multicenter, randomized, placebo-controlled, phase 3 study, is underway. Methods: Key eligibility criteria are age ≥18 years; previously untreated unresectable or metastatic HER2+ (centrally confirmed IHC 3+ or IHC 2+/ISH > 2.0) G/GEJ cancer; life expectancy > 6 months with RECIST v1.1 measurable disease; and adequate organ function and performance status (ECOG PS of 0 or 1). Patients will be randomly assigned 1:1 to receive chemotherapy with pembrolizumab 200 mg intravenously (IV) or placebo with trastuzumab 6 mg/kg (after 8 mg/kg load) every 3 weeks (Q3W) up to 2 years or until intolerable toxicity or disease progression. Investigator-choice chemotherapy will include day 1 cisplatin 80 mg/m2 IV and 5-fluorouracil 800 mg/m2/day IV (days 1-5) or oxaliplatin 130 mg/m2 IV and capecitabine 1000 mg/m2 BID days 1-14 (Q3W). Primary end points are progression-free survival and overall survival. Secondary end points are objective response rate, duration of response, and safety and tolerability. Adverse events are graded per CTCAE v4.0 and will be monitored for 30 or 90 days after treatment. Patients will be followed up for survival. Planned enrollment is approximately 692 patients. Clinical trial information: NCT03615326.

Health-related quality of life (HRQoL) of pembrolizumab (pembro) versus physician choice single-agent paclitaxel, docetaxel, or irinotecan in subjects with advanced/metastatic adenocarcinoma (ACC) or squamous cell carcinoma (SCC) of the esophagus that has progressed after first-line standard therapy (KEYNOTE-181)

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Background: KEYNOTE-181 (NCT02564263) is an open-label, randomized, phase 3 trial in ACC and SCC of the esophagus that evaluated IV pembro 200 mg Q3W for up to 2 years vs investigator choice of single-agent paclitaxel/docetaxel/irinotecan (control). Pembro was superior to control for OS in patients with PD-L1 CPS ≥10 (N = 222; median 9.3 vs 6.7 months; P= 0.0074). Here we present results of prespecified HRQoL analyses in this population. Methods: The EORTC QLQ-C30 and EORTC QLQ-OES18 were administered at baseline; weeks 2, 3, 4, 6, 9, 12, 18; every 9 weeks up to 1 year/end of treatment; and 30-day safety follow-up visit. Data from patients receiving ≥1 dose of study treatment and completing ≥1 HRQoL assessment were analyzed. Least squares mean (LSM) score change from baseline to week 9, 95% CI, and nominal P values were calculated. Time to deterioration (TTD) (≥10-point decline from baseline) was assessed by Kaplan-Meier method and Cox regression model. HRs, 95% CIs, and nominal P values are provided. Results: The HRQoL population included 218 PD-L1 CPS ≥10 patients (107 pembro, 111 control). QLQ-C30 compliance at week 9 was 88.9% for pembro and 83.9% for control. There was no significant difference in LSM between arms (3.68; 95% CI –2.28, 9.64; P= 0.2248) in global health status (GHS)/QoL score. Week 9 QLQ-OES18 compliance was 88.4% for pembro and 83.3% for control. QLQ-OES18 scores were not significantly different between arms. TTD for pain (HR 1.02; 95% CI 0.58, 1.81; P= 0.5282), reflux (HR 1.69; 95% CI 0.83, 3.47; P= 0.9254), and dysphagia (HR 1.81; 95% CI 0.97, 3.37; P= 0.9693) subscales were not significantly different between arms. Conclusions: Over 9 weeks, patients treated with pembro had stable GHS/QoL scores similar to those of patients treated with single-agent docetaxel/paclitaxel/irinotecan. Combined with the superior OS and lower rate of treatment-related AEs seen with pembro, these data support clinically meaningful benefit of pembro in esophageal cancer patients with PD-L1 CPS ≥10. Clinical trial information: NCT02564263.

Pembrolizumab versus chemotherapy as second-line therapy for advanced esophageal cancer: Phase 3 KEYNOTE-181 study

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Background: The phase 3 KEYNOTE-181 study compared pembrolizumab (pembro) vs chemo as second-line therapy for patients (pts) with advanced/metastatic squamous cell carcinoma (SCC) and adenocarcinoma (ACC) of the esophagus (NCT02564263). Methods: Eligible pts were randomized 1:1 to pembro 200 mg Q3W for up to 2 years or choice of paclitaxel, docetaxel, or irinotecan. Randomization was stratified by histology (SCC vs adenocarcinoma) and region (Asia vs rest of world). Primary end points were OS in the SCC, PD-L1 combined positive score (CPS) ≥10, and the ITT. Secondary endpoints included PFS, ORR, safety; exploratory endpoints included health-related quality of life (HRQoL) in CPS ≥10. Results: 628 pts were randomized (401 with SCC; 222 with CPS ≥10). As of Oct. 15, 2018, median follow-up was 7.1 mo (pembro) vs 6.9 mo (chemo). In CPS ≥10, OS was superior with pembro vs chemo (median 9.3 vs 6.7 mo; HR 0.69; 95% CI 0.52-0.93; P= 0.0074). In CPS ≥10 SCC, median OS was 10.3 mo vs 6.7 mo and in CPS ≥10 ACC, median OS was 6.3 mo vs 6.9 mo; 12-mo OS rates were higher with pembro vs chemo (Table). In SCC, median OS was 8.2 mo vs 7.1 mo; HR 0.78; 95% CI 0.63-0.96; P= 0.0095. In the ITT, median OS was 7.1 mo vs 7.1 mo; HR 0.89; 95% CI 0.75-1.05; P= 0.0560. Updated OS will be presented. Grade 3-5 drug-related AEs (≥10% incidence in either arm) included decreased white blood cells (0% vs 10%), decreased neutrophils (0.3% vs 10%). In CPS ≥10, HRQoL improved with pembro vs chemo only for EQ-5D VAS (difference in LS mean change from baseline 5.57; 95% CI 0.58-10.56). Conclusions: Pembro significantly improved OS vs chemo as second-line therapy for advanced esophageal cancer with PD-L1 CPS ≥10, with a more favorable safety profile and stable and similar QOL. These data support pembro as a new second-line standard of care for esophageal cancer with PD-L1 CPS ≥10. Clinical trial information: NCT02564263. [Table: see text]

Efficacy and Safety of Pembrolizumab for Heavily Pretreated Patients With Advanced, Metastatic Adenocarcinoma or Squamous Cell Carcinoma of the Esophagus: The Phase 2 KEYNOTE-180 Study

IMPORTANCE

Effective treatment options are limited for patients with advanced, metastatic esophageal cancer progressing after 2 or more lines of systemic therapy.

OBJECTIVE

To evaluate the efficacy and safety of pembrolizumab for patients with advanced, metastatic esophageal squamous cell carcinoma (ESCC) or advanced, metastatic adenocarcinoma of the esophagus and gastroesophageal junction that progressed after 2 or more lines of systemic therapy.

DESIGN, SETTING, AND PARTICIPANTS

This phase 2, open-label, interventional, single-arm study, KEYNOTE-180, enrolled 121 patients from January 12, 2016, to March 21, 2017, from 57 sites in 10 countries. Patients had advanced, metastatic esophageal cancer that progressed after 2 or more lines of therapy and had evaluable tumor samples for biomarkers.

INTERVENTIONS

Pembrolizumab, 200 mg, was administered intravenously every 3 weeks until disease progression, unacceptable toxic effects, or study withdrawal, for up to 2 years.

MAIN OUTCOMES AND MEASURES

Primary end point was objective response rate per the Response Evaluation Criteria in Solid Tumors by central imaging review for all patients.

RESULTS

As of September 18, 2017, of 121 enrolled patients (100 men and 21 women; median age, 65 years [range, 33-87 years]), 18 (14.9%) had undergone 3 or more prior therapies, 63 (52.1%) had ESCC, and 58 (47.9%) had tumors positive for programmed death ligand-1 (PD-L1), defined as a combined positive score of 10 or higher assessed by immunohistochemistry. Median duration of follow-up was 5.8 months (range, 0.2-18.3 months). Objective response rate was 9.9% (95% CI, 5.2%-16.7%) among all patients (12 of 121), and median duration of response was not reached (range, 1.9-14.4 months). Objective response rate was 14.3% (95% CI, 6.7%-25.4%) among patients with ESCC (9 of 63), 5.2% (95% CI, 1.1%-14.4%) among patients with adenocarcinoma (3 of 58), 13.8% (95% CI, 6.1%-25.4%) among patients with PD-L1-positive tumors (8 of 58), and 6.3% (95% CI, 1.8%-15.5%) among patients with PD-L1-negative tumors (4 of 63). Overall, 15 patients (12.4%) had treatment-related grade 3 to 5 adverse events. Only 5 patients (4.1%) discontinued treatment because of adverse events. There was 1 treatment-related death from pneumonitis.

CONCLUSIONS AND RELEVANCE

Where effective treatment options are an unmet need, pembrolizumab provided durable antitumor activity with manageable safety in patients with heavily pretreated esophageal cancer. Phase 3 studies evaluating pembrolizumab vs standard therapy for patients with esophageal cancer progressing after first-line therapy or in combination with chemotherapy as first-line therapy for patients with locally advanced unresectable or metastatic esophageal cancer are ongoing.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02559687.

Efficacy and Safety of Pembrolizumab for Heavily Pretreated Patients With Advanced, Metastatic Adenocarcinoma or Squamous Cell Carcinoma of the Esophagus: The Phase 2 KEYNOTE-180 Study

Importance

Effective treatment options are limited for patients with advanced, metastatic esophageal cancer progressing after 2 or more lines of systemic therapy.

Objective

To evaluate the efficacy and safety of pembrolizumab for patients with advanced, metastatic esophageal squamous cell carcinoma (ESCC) or advanced, metastatic adenocarcinoma of the esophagus and gastroesophageal junction that progressed after 2 or more lines of systemic therapy.

Design, Setting, and Participants

This phase 2, open-label, interventional, single-arm study, KEYNOTE-180, enrolled 121 patients from January 12, 2016, to March 21, 2017, from 57 sites in 10 countries. Patients had advanced, metastatic esophageal cancer that progressed after 2 or more lines of therapy and had evaluable tumor samples for biomarkers.

Interventions

Pembrolizumab, 200 mg, was administered intravenously every 3 weeks until disease progression, unacceptable toxic effects, or study withdrawal, for up to 2 years.

Main Outcomes and Measures

Primary end point was objective response rate per the Response Evaluation Criteria in Solid Tumors by central imaging review for all patients.

Results

As of September 18, 2017, of 121 enrolled patients (100 men and 21 women; median age, 65 years [range, 33-87 years]), 18 (14.9%) had undergone 3 or more prior therapies, 63 (52.1%) had ESCC, and 58 (47.9%) had tumors positive for programmed death ligand-1 (PD-L1), defined as a combined positive score of 10 or higher assessed by immunohistochemistry. Median duration of follow-up was 5.8 months (range, 0.2-18.3 months). Objective response rate was 9.9% (95% CI, 5.2%-16.7%) among all patients (12 of 121), and median duration of response was not reached (range, 1.9-14.4 months). Objective response rate was 14.3% (95% CI, 6.7%-25.4%) among patients with ESCC (9 of 63), 5.2% (95% CI, 1.1%-14.4%) among patients with adenocarcinoma (3 of 58), 13.8% (95% CI, 6.1%-25.4%) among patients with PD-L1-positive tumors (8 of 58), and 6.3% (95% CI, 1.8%-15.5%) among patients with PD-L1-negative tumors (4 of 63). Overall, 15 patients (12.4%) had treatment-related grade 3 to 5 adverse events. Only 5 patients (4.1%) discontinued treatment because of adverse events. There was 1 treatment-related death from pneumonitis.

Conclusions and Relevance

Where effective treatment options are an unmet need, pembrolizumab provided durable antitumor activity with manageable safety in patients with heavily pretreated esophageal cancer. Phase 3 studies evaluating pembrolizumab vs standard therapy for patients with esophageal cancer progressing after first-line therapy or in combination with chemotherapy as first-line therapy for patients with locally advanced unresectable or metastatic esophageal cancer are ongoing.

Trial Registration

ClinicalTrials.gov identifier: NCT02559687.

Pembrolizumab versus chemotherapy as second-line therapy for advanced esophageal cancer: Phase III KEYNOTE-181 study

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Background: Patients with advanced esophageal cancer after first-line chemotherapy (chemo) have a poor prognosis and limited treatment options. We present results of the phase 3 KEYNOTE-181 study of pembrolizumab vs investigator’s choice chemo as second-line therapy for patients (pts) with advanced/metastatic squamous cell carcinoma (SCC) and adenocarcinoma of the esophagus or Siewert type I adenocarcinoma of the EGJ (NCT02564263). Methods: Eligible pts were randomized 1:1 to pembrolizumab 200 mg Q3W for up to 2 years or investigator’s choice chemo of paclitaxel, docetaxel, or irinotecan. Randomization was stratified by histology (SCC vs adenocarcinoma) and region (Asia vs rest of world). Primary end points were OS in the SCC, PD-L1 combined positive score (CPS) ≥10, and ITT populations. Results: 628 pts were randomized including 401 with SCC, and 222 with CPS ≥10. As of October 15, 2018, the median follow-up was 7.1 mo (pembrolizumab) vs 6.9 mo (chemo). Pembrolizumab was superior to chemo for OS in CPS ≥10 (N=222; median 9.3 vs 6.7 mo; HR 0.69; 95% CI 0.52-0.93; P=0.0074). The 12-mo OS rate in pts with CPS ≥10 was 43% vs 20%. There was clinically meaningful improvement in OS with pembrolizumab vs chemo in pts with SCC, but this was not statistically significant per prespecified boundaries (N=401; 8.2 mo vs 7.1 mo; HR 0.78; 95% CI 0.63-0.96; P=0.0095). In the ITT population, while directionally favorable, the difference in OS was not statistically significant (N=628; 7.1 mo vs 7.1 mo; HR 0.89; 95% CI 0.75-1.05; P=0.0560). Fewer pts had any-grade (64% vs 86%) or grade 3-5 (18% vs 41%) drug-related AEs with pembrolizumab vs chemo. Conclusion: Pembrolizumab significantly improved OS compared with chemo as second-line therapy for advanced esophageal cancer with PD-L1 CPS ≥10, with a more favorable safety profile. These data support pembrolizumab as a new second-line standard of care for esophageal cancer with PD-L1 CPS ≥10. The phase 3 KEYNOTE-590 study of pembrolizumab plus chemo as first-line therapy for advanced esophageal cancer is ongoing (NCT03189719). Clinical trial information: NCT02564263.