First-line pembrolizumab plus chemotherapy for advanced/metastatic esophageal cancer: 1-year extended follow-up in the Japanese subgroup of the phase 3 KEYNOTE-590 study.

BACKGROUND: First-line pembrolizumab plus chemotherapy (pembrolizumab-chemotherapy) demonstrated improved efficacy and a manageable safety profile versus placebo plus chemotherapy (placebo-chemotherapy) in the subgroup analysis of Japanese patients with advanced/metastatic esophageal cancer in KEYNOTE-590 at a median follow-up of 24.4 months. Longer-term data from the Japanese subgroup analysis of KEYNOTE-590 are reported. METHODS: Patients were randomly assigned 1:1 to pembrolizumab 200 mg or placebo every 3 weeks for ≤ 35 cycles plus chemotherapy (cisplatin 80 mg/m2 and 5-fluorouracil 800 mg/m2/day). Endpoints included overall survival (OS) and progression-free survival (PFS; investigator-assessed per RECIST v1.1; dual primary) and safety (secondary). Early tumor shrinkage (ETS) and depth of response (DpR) were assessed post hoc. RESULTS: Overall, 141 patients were enrolled in Japan. As of July 9, 2021, median follow-up was 36.6 months (range, 29.8-45.7). Pembrolizumab-chemotherapy showed a trend toward favorable OS (hazard ratio [HR], 0.70; 95% confidence interval [CI] 0.47-1.03) and PFS (0.57; 0.39-0.83) versus placebo-chemotherapy. In the pembrolizumab-chemotherapy group, patients with ETS ≥ 20% (55/74; 74.3%) versus < 20% (19/74; 25.7%) had favorable OS (HR, 0.23; 95% CI 0.12-0.42) and PFS (0.24; 0.13-0.43). Patients with DpR ≥ 60% (31/74; 41.9%) versus < 60% (43/74; 58.1%) had favorable OS (HR, 0.37; 95% CI 0.20-0.68) and PFS (0.24; 0.13-0.43). Grade 3-5 treatment-related adverse events occurred in 55/74 patients (74.3%) with pembrolizumab-chemotherapy and 41/67 patients (61.2%) with placebo-chemotherapy. CONCLUSIONS: With longer-term follow-up of Japanese patients with advanced/metastatic esophageal cancer, efficacy continued to favor pembrolizumab-chemotherapy compared with placebo-chemotherapy, with no new safety signals observed. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT03189719.

KEYNOTE-434 part B: A phase 1 study evaluating the combination of epacadostat, pembrolizumab, and chemotherapy in Japanese patients with previously untreated advanced non-small-cell lung cancer.

BACKGROUND: Pembrolizumab plus epacadostat (indoleamine 2,3-dioxygenase-1 inhibitor) was well tolerated in Japanese patients with advanced solid tumors in part A of the nonrandomized, open-label, phase 1 KEYNOTE-434 study (NCT02862457). We report results from part B, which evaluated epacadostat plus pembrolizumab and chemotherapy in Japanese patients with advanced non-small-cell lung cancer (NSCLC). METHODS: Eligible patients aged ≥ 20 years had histologically or cytologically confirmed stage IIIB or IV NSCLC with no prior systemic therapy, and ECOG performance status of 0 or 1. Patients received epacadostat 100 mg orally twice-daily, pembrolizumab 200 mg intravenously every-3-weeks for ≤ 35 cycles, and 4 cycles of chemotherapy (cohort 1: cisplatin plus pemetrexed, non-squamous; cohort 2: carboplatin plus pemetrexed, non-squamous; cohort 3: carboplatin plus paclitaxel, squamous or non-squamous). Primary endpoint was incidence of dose-limiting toxicities (DLTs). Following unfavorable results from other studies, a protocol amendment removed epacadostat from the treatment combination. RESULTS: Of 19 patients, 7 were enrolled in cohort 1, and 6 each in cohorts 2 and 3. Median follow-up was 13.7 (range, 4.2-27.8) months. Five of 17 (29%) DLT-evaluable patients experienced ≥ 1 DLT (cohort 1, n = 1; cohorts 2 and 3, n = 2 each); most commonly maculopapular rash (grade 3, n = 3) and increased alanine aminotransferase (grade 2, n = 1; grade 3, n = 2). All patients experienced treatment-related adverse events (AEs); 58% experienced grade 3 or 4 treatment-related AEs. Objective response rate was 47%. CONCLUSION: The combination of epacadostat plus pembrolizumab and chemotherapy was found to be tolerable in Japanese patients with advanced NSCLC. TRIAL REGISTRATION: ClinicalTrials.gov , NCT02862457.

Long-term follow-up results from KEYNOTE-041: Phase 1b study of pembrolizumab in Japanese patients with advanced melanoma.

Pembrolizumab demonstrated an acceptable safety profile and promising antitumor activity in Japanese patients with advanced melanoma in the phase 1b KEYNOTE-041 (Study of Pembrolizumab [MK-3475] in Participants With Advanced Melanoma) trial. To evaluate the long-term efficacy and safety of pembrolizumab in Japanese patients with advanced melanoma in KEYNOTE-041. The current analysis reports results of additional follow-up of approximately 12 months since the initial analysis. Eligible patients had locally advanced (unresectable stage III) or metastatic (stage IV) melanoma not amenable to local therapy and had received two or fewer prior systemic therapies. Pembrolizumab 2 mg/kg was given every 3 weeks for up to 2 years or until confirmed progression or unacceptable toxicity. Primary end points included safety, tolerability, and overall response rate (ORR) per Response Evaluation Criteria in Solid Tumors version 1.1 by independent central review. The data cutoff for this analysis was August 30, 2017. Forty-two patients were followed up for a median of 22.3 months (range, 2.63-30.82 months). The ORR was 24.3% (nine of 37 evaluable patients [95% confidence interval (CI), 11.8%-41.2%]). Two patients with partial response at the time of the initial analysis achieved complete response. The median overall survival (OS) was 25.1 months (95% CI, 13.1-not reached] and the 30-month OS rate was 46.3% (95% CI, 29.8%-61.3%). The median duration of response was not reached. Treatment-related adverse events (TRAEs) were reported in 78.6% of patients; the incidence of grade 3 to 5 TRAEs was 23.8%. No additional treatment-related deaths occurred since the initial analysis. Pembrolizumab provided durable antitumor activity and an acceptable safety profile in Japanese patients with advanced melanoma.

Analysis of East Asia subgroup in Study 309/KEYNOTE-775: lenvatinib plus pembrolizumab versus treatment of physician's choice chemotherapy in patients with previously treated advanced or recurrent endometrial cancer.

OBJECTIVE: In the global phase 3 Study 309/KEYNOTE-775 (NCT03517449) at the first interim analysis, lenvatinib+pembrolizumab significantly improved progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) versus treatment of physician's choice chemotherapy (TPC) in patients with previously treated advanced/recurrent endometrial cancer (EC). This exploratory analysis evaluated outcomes in patients enrolled in East Asia at the time of prespecified final analysis. METHODS: Women ≥18 years with histologically confirmed advanced, recurrent, or metastatic EC with progressive disease after 1 platinum-based chemotherapy (2 if 1 given in neoadjuvant/adjuvant setting) were enrolled. Patients were randomized 1:1 to lenvatinib 20 mg orally once daily plus pembrolizumab 200 mg intravenously every 3 weeks (≤35 cycles) or TPC (doxorubicin or paclitaxel). Primary endpoints were PFS per RECIST v1.1 by blinded independent central review and OS. No alpha was assigned for this subgroup analysis. RESULTS: Among 155 East Asian patients (lenvatinib+pembrolizumab, n=77; TPC, n=78), median follow-up time (data cutoff: March 1, 2022) was 34.3 (range, 25.1-43.0) months. Hazard ratios (HRs) with 95% confidence intervals (CIs) for PFS (lenvatinib+pembrolizumab vs. TPC) were 0.74 (0.49-1.10) and 0.64 (0.44-0.94) in the mismatch repair proficient (pMMR) and all-comer populations, respectively. HRs (95% CI) for OS were 0.68 (0.45-1.02) and 0.61 (0.41-0.90), respectively. ORRs were 36% with lenvatinib+pembrolizumab and 22% with TPC (pMMR) and 39% and 21%, respectively (all-comers). Treatment-related adverse events occurred in 97% and 96% (grade 3-5, 74% and 72%), respectively. CONCLUSION: Lenvatinib+pembrolizumab provided clinically meaningful benefit with manageable safety compared with TPC, supporting its use in East Asian patients with previously treated advanced/recurrent EC. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03517449.

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

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

Efficacy of Pembrolizumab Monotherapy in Japanese Patients with Advanced Gastric or Gastroesophageal Junction Cancer.

PURPOSE: Pembrolizumab demonstrated antitumor activity in programmed death ligand 1 positive (combined positive score (CPS) ≥ 1) gastric/gastroesophageal junction cancer in KEYNOTE-059 (third line or beyond), KEYNOTE-061 (second line), and KEYNOTE-062 (first line). We characterized efficacy and safety of pembrolizumab monotherapy in Japanese patients across several lines of therapy in these studies. METHODS: This analysis was conducted in 34 patients from KEYNOTE-059 cohort 1 (all pembrolizumab), including 13 patients with CPS ≥ 1, 65 patients with CPS ≥ 1 from KEYNOTE-061 (pembrolizumab, n = 27; chemotherapy, n = 38), and 70 patients with CPS ≥ 1 from KEYNOTE-062 (pembrolizumab, n = 38; chemotherapy, n = 32). Overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and safety were evaluated. RESULTS: In KEYNOTE-059, ORR with pembrolizumab was 9%, median PFS was 2 months, and median OS was 10 months. In KEYNOTE-061, median OS was 12 months with pembrolizumab versus 10 months with chemotherapy (hazard ratio (HR), 0.67; 95% confidence interval (CI), 0.39-1.15). Median PFS (pembrolizumab vs. chemotherapy) was 2 months versus 4 months (HR, 1.21; 95% CI, 0.69-2.13); ORR was 7% versus 18%. In KEYNOTE-062, median OS was 20 months with pembrolizumab versus 18 months with chemotherapy (HR, 0.76; 95% CI, 0.43-1.33). Median PFS (pembrolizumab vs. chemotherapy) was 6 months versus 7 months (HR, 1.03; 95% CI, 0.61-1.74); ORR was 29% versus 34%. CONCLUSIONS: The current analysis provides valuable information that anti-PD-1 therapies are worthy of further assessment for gastric cancer. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02335411 (KEYNOTE-059), NCT02370498 (KEYNOTE-061), and NCT02494583 (KEYNOTE-062).

Phase IIb study of pembrolizumab combined with S-1 + oxaliplatin or S-1 + cisplatin as first-line chemotherapy for gastric cancer.

The KEYNOTE-659 study evaluated the efficacy and safety of first-line pembrolizumab plus S-1 and oxaliplatin (SOX) (cohort 1) or S-1 and cisplatin (SP) (cohort 2) for advanced gastric/gastroesophageal junction (G/GEJ) cancer in Japan. Herein, we update the results of cohort 1 and describe the results of cohort 2. This open-label phase IIb study enrolled patients with advanced programmed death-ligand 1 (PD-L1)-positive (combined positive score ≥ 1) human epidermal growth factor receptor 2 (HER2)-negative G/GEJ adenocarcinoma. The primary end-point was the objective response rate (ORR). Other end-points were duration of response (DOR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety. One hundred patients were enrolled. In cohorts 1 and 2, median follow-up time was 16.9 and 17.1 months; ORR (central review), 72.2% and 80.4%; DOR, 10.6 and 9.5 months; DCR (central review), 96.3% and 97.8%; median PFS (central review), 9.4 and 8.3 months; and median OS, 16.9 and 17.1 months, respectively. Treatment-related adverse events (TRAEs) occurred in all patients, including peripheral sensory neuropathy (94.4%, cohort 1), decreased neutrophil count (82.6%, cohort 2), nausea (59.3% and 60.9% in cohorts 1 and 2), and decreased appetite (61.1% and 60.9% in cohorts 1 and 2). Grade 3 or higher TRAEs were reported by 59.3% (cohort 1) and 78.3% (cohort 2), including decreased platelet count (14.8%, cohort 1) and decreased neutrophil count (52.2%, cohort 2). Pembrolizumab in combination with SOX or SP showed favorable efficacy and safety in patients with PD-L1-positive, HER2-negative G/GEJ adenocarcinoma.

First-line pembrolizumab + chemotherapy in Japanese patients with advanced/metastatic esophageal cancer from KEYNOTE-590.

BACKGROUND: The phase 3 KEYNOTE-590 (NCT03189719) study showed first-line pembrolizumab plus chemotherapy significantly prolonged overall survival and progression-free survival versus placebo plus chemotherapy in patients with advanced unresectable or metastatic adenocarcinoma or squamous cell carcinoma of the esophagus or advanced/metastatic Siewert type I adenocarcinoma of the esophagogastric junction. We describe a subgroup analysis of Japanese patients from KEYNOTE-590. METHODS: Eligible patients were randomly assigned 1:1 to pembrolizumab 200 mg intravenously every 3 weeks or placebo plus chemotherapy (cisplatin 80 mg/m2 and 5-fluorouracil 800 mg/m2/day). Efficacy was evaluated in all Japanese patients and those with esophageal squamous cell carcinoma and programmed death ligand 1 combined positive score ≥ 10. Dual primary endpoints were overall survival and progression-free survival per RECIST v1.1 by investigator. Secondary endpoints included objective response rate per RECIST v1.1 by investigator and safety and tolerability. RESULTS: At data cutoff (July 2, 2020), 141 Japanese patients were randomly assigned (pembrolizumab plus chemotherapy, 74; placebo plus chemotherapy, 67). In all Japanese patients, median overall survival was 17.6 months with pembrolizumab plus chemotherapy versus 11.7 months with chemotherapy (hazard ratio, 0.71; 95% confidence interval, 0.47-1.09), median progression-free survival was 6.3 versus 6.0 months (hazard ratio, 0.58; 95% confidence interval, 0.40-0.84), and objective response rate was 56.8% versus 38.8%. Grade 3-5 treatment-related adverse events were 74.3% and 61.2%. CONCLUSION: First-line pembrolizumab plus chemotherapy demonstrated improvement in overall survival and progression-free survival compared with placebo plus chemotherapy in Japanese patients with advanced/metastatic esophageal cancer; safety was comparable between treatment groups. CLINICAL TRIAL REGISTRY: ClinicalTrials.gov, NCT03189719.

Lenvatinib plus pembrolizumab in Japanese patients with endometrial cancer: Results from Study 309/KEYNOTE-775.

Study 309/KEYNOTE-775 is a phase 3 open-label, randomized trial of lenvatinib plus pembrolizumab versus treatment of physician's choice (TPC) in patients with advanced endometrial cancer with progression after platinum-based therapy. Primary endpoints of superiority for lenvatinib plus pembrolizumab were met for progression-free survival (PFS) and overall survival (OS) in all-comers (ie, regardless of mismatch repair [MMR] status) and patients with MMR proficiency (pMMR). We present results for the Japanese subset. Patients were randomized to oral lenvatinib 20 mg/day plus intravenous pembrolizumab 200 mg every 3 weeks (Q3W; up to 35 cycles of pembrolizumab) or TPC (intravenous doxorubicin 60 mg/m2 Q3W or paclitaxel 80 mg/m2 QW [3 weeks on/1 week off]). Primary endpoints were PFS by blinded independent central review per RECIST version 1.1 and OS. One hundred four patients were randomized in Japan (data cutoff, October 26, 2020; median follow-up, 11.8 [range, 1.1-26.9] months). Hazard ratios (HRs) for PFS with lenvatinib plus pembrolizumab versus TPC were 1.04 (95% CI, 0.63-1.73) in patients with pMMR and 0.81 (0.50-1.31) in all-comers. Hazard ratios for OS were 0.74 (0.41-1.34) with pMMR and 0.59 (0.33-1.04) for all-comers. Adverse events were manageable and led to discontinuation of one/both study drugs in 36.5% of patients in the lenvatinib plus pembrolizumab group versus 7.8% in the TPC group. Similar to the global Study 309/KEYNOTE-775 results, this analysis suggested favorable efficacy and manageable safety with lenvatinib plus pembrolizumab after platinum-based chemotherapy in Japanese patients with advanced endometrial cancer and supports this combination as a new standard of care in this population.

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.

Phase 1 study of pembrolizumab plus chemotherapy as first-line treatment in Japanese patients with advanced NSCLC.

INTRODUCTION: Pembrolizumab plus chemotherapy significantly improved outcomes over chemotherapy alone as first-line treatment in patients with advanced non-small-cell lung cancer (NSCLC) in phase 3 international trials. In the phase 1 KEYNOTE-011 study (parts B and C), we evaluated the safety/activity of pembrolizumab plus chemotherapy as first-line treatment in Japanese patients with advanced NSCLC. METHODS: Eligible patients received 4 cycles (every 3 weeks) of pembrolizumab 200 mg plus chemotherapy (cisplatin 75 mg/m2/carboplatin area under the curve [AUC] 5 mg/mL/min and pemetrexed 500 mg/m2 in part B [nonsquamous]; carboplatin AUC 6 mg/mL/min and paclitaxel 200 mg/m2/nab-paclitaxel 100 mg/m2 (weekly) in part C [squamous]), followed by maintenance pembrolizumab (and pemetrexed, part B). The primary endpoint was incidence of dose-limiting toxicities (DLTs) during the first 3 weeks of treatment. Overall response rate (ORR; RECIST v1.1 by central review) was exploratory. RESULTS: In part B (median follow-up, 16.0 months; n = 12) 1 DLT occurred (grade 4 hyponatremia). Grade ≥3 treatment-related adverse events (AEs) occurred in 9 patients (75%). Two patients had grade 5 treatment-related AEs (pneumonitis and interstitial lung disease). In part C (median follow-up, 9.9 months; n = 14), 2 DLTs occurred (both grade 3 febrile neutropenia). Grade ≥3 treatment-related AEs occurred in 11 patients (79%); none were fatal. ORR was 73% in part B and 50% in part C, irrespective of PD-L1 status. CONCLUSION: Safety results show first-line pembrolizumab plus chemotherapy is feasible in Japanese patients with advanced NSCLC. Antitumor activity was observed irrespective of PD-L1 status and was comparable to that in international studies. TRIAL REGISTER: ClinicalTrials.gov, NCT01840579.