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

430

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

TPS463

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

2

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.