Blockade

Receptor

Placebo

Immunology

Alternative medicine

Trastuzumab

Pembrolizumab

Internal medicine

Chemotherapy

Oncology

Medicine

Immunotherapy

Gastroenterology

Breast cancer

Antibody

Cancer

Pathology

Nature

Human epidermal growth factor receptor 2 (HER2, also known as ERBB2) amplification or overexpression occurs in approximately 20% of advanced gastric or gastro-oesophageal junction adenocarcinomas1,2,3. More than a decade ago, combination therapy with the anti-HER2 antibody trastuzumab and chemotherapy became the standard first-line treatment for patients with these types of tumours4. Although adding the anti-programmed death 1 (PD-1) antibody pembrolizumab to chemotherapy does not significantly improve efficacy in advanced HER2-negative gastric cancer5, there are preclinical6,7,8,9,10,11,12,13,14,15,16,17,18,19 and clinical20,21 rationales for adding pembrolizumab in HER2-positive disease. Here we describe results of the protocol-specified first interim analysis of the randomized, double-blind, placebo-controlled phase III KEYNOTE-811 study of pembrolizumab plus trastuzumab and chemotherapy for unresectable or metastatic, HER2-positive gastric or gastro-oesophageal junction adenocarcinoma22 (https://clinicaltrials.gov, NCT03615326). We show that adding pembrolizumab to trastuzumab and chemotherapy markedly reduces tumour size, induces complete responses in some participants, and significantly improves objective response rate.

The KEYNOTE-811 trial of dual PD-1 and HER2 blockade in HER2-positive gastric cancer