TRASTUZUMAB DERUXTECAN

The PBAC did not recommend listing trastuzumab deruxtecan (Enhertu®) on the PBS for the treatment of adult patients with hormone receptor positive (HR-positive) human epidermal growth factor receptor 2 (HER2)-low or HER2-ultralow unresectable and/or metastatic breast cancer (mBC) who have received at least one prior line of endocrine therapy (ET) in the metastatic setting and are no longer suitable for further ET. The PBAC welcomed input  from health professionals and organisations, which highlighted the burden of metastatic breast cancer and its treatment on patients and noted the value of choice in deciding the order of treatments for mBC.

The PBAC accepted that trastuzumab deruxtecan was more effective than chemotherapy in improving the length of time that patients lived without their cancer getting worse in patients with HER2-low mBC, but considered that the evidence included in the submission did not allow confidence about the extent of benefit for patients with HER2-ultralow mBC because of the small number of these patients in the trial and uncertainty in the testing to identify HER2-ultralow mBC. The PBAC noted that trastuzumab deruxtecan caused a clear increase in harms compared with chemotherapy including life-threatening adverse events, and did not appear to extend life expectancy. 

The claimed benefits of trastuzumab deruxtecan were, in the PBAC’s view, uncertain and overestimated. The PBAC advised that trastuzumab deruxtecan was not cost effective at the price requested when more realistic estimates of benefits and costs were considered.