Trastuzumab deruxtecan is not recommended, within its marketing authorisation, for treating HER2‑low metastatic or unresectable breast cancer in adults after:
chemotherapy in the metastatic setting or
recurrence during adjuvant chemotherapy or within 6 months after finishing it.
This recommendation is not intended to affect treatment with trastuzumab deruxtecan 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
HER2‑low is a newly classified subgroup of breast cancer previously considered HER2‑negative. People with HER2‑low metastatic or unresectable breast cancer have cancer cells with low amounts of HER2. They are offered treatments for HER2‑negative cancer; which type depends on whether the cancer is hormone-receptor negative or positive. Sacituzumab govitecan is a possible treatment for triple-negative breast cancer. Trastuzumab deruxtecan is the first licensed treatment for HER2‑low metastatic or unresectable breast cancer, and it specifically targets HER2.
Clinical trial evidence shows that trastuzumab deruxtecan increases how long people live and how long they have before their cancer gets worse compared with chemotherapy treatments used for HER2‑negative breast cancer. Because of a lack of evidence, it is not possible to reliably compare trastuzumab deruxtecan with sacituzumab govitecan.
Despite accounting for the condition's severity, by applying a severity modifier, and accounting for innovation and uncaptured benefits, the most likely cost-effectiveness estimate are above the upper end of the range NICE considers an acceptable use of NHS resources. So, trastuzumab deruxtecan is not recommended.