Drug guidance
Pembrolizumab for treating locally advanced unresectable or metastatic HER2-positive gastric or gastroesophageal junction adenocarcinoma
5 October 2026
Condition
Cancer
Gastrointestinal tract
Published on 17 Feb 2025
Last Updated on 05 Oct 2026
Guidance Recommendations
The Ministry of Health’s Drug Advisory Committee has recommended:
Pembrolizumab 100 mg/4 mL solution for infusion, in combination with trastuzumab, fluoropyrimidine- and platinum-containing chemotherapy, for untreated locally advanced unresectable or metastatic human epidermal growth factor receptor 2 (HER2)-positive gastric or gastroesophageal junction adenocarcinoma, in patients whose tumours express programmed death-ligand 1 with a combined positive score greater than or equal to 1.
Funding status
Pembrolizumab 100 mg/4 mL solution for infusion is recommended for inclusion on the Medication Assistance Fund (MAF) for the abovementioned indication from 1 December 2026.
Clinical indication, subsidy class and MediShield Life claims eligibility for pembrolizumab are provided in the Annex.
Plain English Summary
Gastric cancer occurs when cells in the stomach grow uncontrollably and form a mass (tumour). Adenocarcinoma is the most common type. Cancer that develops where the oesophagus joins the stomach is known as gastroesophageal junction (GEJ) cancer. Symptoms of gastric or GEJ cancer can include difficulty swallowing, feeling full or bloated after eating, loss of appetite, heartburn, and unexplained weight loss. Cancer that has spread to nearby areas and cannot be removed by surgery is called locally advanced unresectable disease. Cancer that has spread to other parts of the body is known as metastatic disease.
Some gastric or GEJ cancers have high levels of a protein called HER2 (human epidermal growth factor 2) which helps cancer cells divide and grow. These cancers are called HER2-positive. Some cancers also have high levels of PD-L1 (programmed death-ligand 1), a protein that can help cancer cells avoid being attacked by the body’s immune system. A combined positive score (CPS) measures the amount of PD-L1 and can help identify which patients may benefit from certain treatments.
Pembrolizumab is an immunotherapy known as a PD-1/PD-L1 checkpoint inhibitor. It helps the body’s immune system find and attack cancer cells. For gastric or GEJ cancers, it is given as a slow drip into a vein (intravenously) in combination with trastuzumab and chemotherapy.
Pembrolizumab, in combination with trastuzumab biosimilar (subsidised brand) and chemotherapy, was recommended for government funding for patients whose tumours have a PD-L1 CPS of 1 or more, because it was considered an acceptable use of healthcare resources. It is included in the Medication Assistance Fund (MAF) (opens in new tab), with its cost subsidised by 40% to 75% for eligible patients. It can also be claimed under MediShield Life. The subsidy class and MediShield Life claim limits are available here (opens in new tab).
Pembrolizumab has not been recommended for subsidy when it is used in combination with a non-subsidised brand of trastuzumab.