Gastric Cancer: Pembrolizumab as Potential New First-Line Standard Therapy
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KEYNOTE-062 Trial Results
- July 8, 2019
- Reading time: 2 minutes
Between May 31 and June 4, 2019, the ASCO 2019 Annual Meeting in Chicago presented results from the KEYNOTE-062 Phase III clinical trial evaluating the safety and efficacy of pembrolizumab monotherapy as first-line treatment for gastric and gastroesophageal junction cancer.
Trial Design and Treatment Arms
KEYNOTE-062 was a Phase III randomized controlled trial with three parallel treatment arms:
Arm 1 - Pembrolizumab Monotherapy:
- Pembrolizumab 200 mg IV on Day 1
- Every 3 weeks
Arm 2 - Pembrolizumab Plus Chemotherapy:
- Pembrolizumab 200 mg IV on Day 1
- Plus Cisplatin 80 mg/m² on Day 1
- Plus 5-Fluorouracil 800 mg/m²/day on Days 1-5, or Capecitabine 1,000 mg/m² twice daily on Days 1-14
- Every 3 weeks
Arm 3 - Placebo Plus Chemotherapy (Control):
- Placebo on Day 1
- Plus Cisplatin 80 mg/m² on Day 1
- Plus 5-Fluorouracil 800 mg/m²/day on Days 1-5, or Capecitabine 1,000 mg/m² twice daily on Days 1-14
- Every 3 weeks
Primary endpoints: progression-free survival and overall survival
Patient Demographics
- Median Age: 62 years
- Tumor Location: Gastric cancer 69%, gastroesophageal junction cancer 30%
- PD-L1 Expression: Combined Positive Score (CPS) ≥1 in 100% of patients; CPS ≥10 in 37% (N=281 patients)
Clinical Trial Results
CPS ≥1 Subgroup (All Enrolled Patients)
Overall Survival (Primary Endpoint):
- Pembrolizumab monotherapy: 10.6 months
- Chemotherapy: 11.1 months
- Hazard Ratio: 0.91
Pembrolizumab monotherapy demonstrated non-inferior overall survival compared to chemotherapy control, meeting trial criteria for equivalence.
CPS ≥10 Subgroup (PD-L1 High-Expressing Tumors)
Overall Survival:
- Pembrolizumab monotherapy: 17.4 months
- Chemotherapy: 10.8 months
- Hazard Ratio: 0.69
2-Year Overall Survival Rate:
- Pembrolizumab: 39%
- Chemotherapy: 22%
Safety Profile
Grade 3+ Adverse Event Incidence:
- Pembrolizumab monotherapy: 17%
- Pembrolizumab plus chemotherapy: 73%
- Chemotherapy alone: 69%
Pembrolizumab monotherapy demonstrated the lowest adverse event rate. Most common treatment-related events included nausea and fatigue. No novel, unexpected adverse events were identified; safety profile was consistent with prior immunotherapy trials.
Clinical Conclusions
Principal investigator Josep Tabernero concluded that in PD-L1 positive, HER2-negative gastric and gastroesophageal junction cancer patients, first-line pembrolizumab monotherapy demonstrates overall survival outcomes comparable to or superior to chemotherapy, potentially establishing a new first-line standard treatment approach.
Related Gastric Cancer Treatment
- Immunotherapy
- Clinical Trial Therapeutics
- (Lung Cancer) Topotecan and Topotecan Plus Berzosertib Phase II Trial Results
- (Lung Cancer) HER2-Mutant Non-Small Cell Lung Cancer Treatment with Enhertu
- (Lung Cancer) Anti-B7-H3 Antibody DS-7300 Clinical Efficacy
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