Pembrolizumab with trastuzumab, fluoropyrimidine- and platinum-containing chemotherapy is not recommended, within its marketing authorisation, for untreated locally advanced unresectable or metastatic HER2‑positive gastric or gastro-oesophageal junction (GOJ) adenocarcinoma in adults whose tumours express PD‑L1 with a combined positive score (CPS) of 1 or more.
This recommendation is not intended to affect treatment with pembrolizumab with trastuzumab, fluoropyrimidine- and platinum-containing chemotherapy that was started in the NHS before this guidance was published. People having treatment outside this recommendation may continue without change to the funding arrangements in place for them before this guidance was published, until they and their NHS clinician consider it appropriate to stop.
Why the committee made these recommendations
There is an unmet need for treatments for untreated locally advanced unresectable or metastatic HER2‑positive gastric or GOJ adenocarcinoma. Usual treatment is trastuzumab plus platinum-containing chemotherapy (from now, trastuzumab plus chemotherapy). Pembrolizumab plus trastuzumab, fluoropyrimidine- and platinum-containing chemotherapy (from now, pembrolizumab plus trastuzumab and chemotherapy) would be used in adults whose tumours express PD‑L1 with a CPS of 1 or more.
Clinical trial evidence suggests that pembrolizumab plus trastuzumab and chemotherapy increases how long people have before their cancer gets worse compared with trastuzumab plus chemotherapy. The evidence suggests it also increases how long they live, but the long-term effect is very uncertain.
When taking into account the committee's preferred assumptions, the cost-effectiveness estimate is not within the range that NICE usually considers an acceptable use of NHS resources. So, pembrolizumab plus trastuzumab and chemotherapy is not recommended.