T-DM1 use may allow neoadjuvant treatment de-escalation in HER2-positive breast cancer
medwireNews: Neoadjuvant treatment with trastuzumab emtansine (T-DM1) is associated with similar pathologic complete response (pCR) rates as the combination of docetaxel, trastuzumab, and pertuzumab (DTP) in patients with HER2-positive breast cancer, study findings indicate.
T-DM1 also had “a more favorable” safety profile and did not adversely affect health-related quality of life (HRQoL), say Thomas Hatschek (Karolinska University Hospital, Stockholm, Sweden) and co-authors in JAMA Oncology.
They continue: “With appropriate patient selection and dynamic therapy adaptation based on early response assessment, T-DM1 may have the potential to become a successful strategy for treatment de-escalation.”
The phase 2 PREDIX HER2 trial included 197 patients with HER2-positive breast cancer who were randomly assigned to receive six cycles of T-DM1 3.6 mg/kg or DTP every 3 weeks.
After a median follow-up of 40.4 months, pCR, defined as ypT0 or Tis ypN0, was achieved by 43.9% of patients given T-DM1 and a comparable 45.5% of patients receiving DTP.
Event-free survival also did not differ significantly between the study treatments, report Hatschek et al, adding that T-DM1 appeared to be better tolerated than DTP.
Specifically, 10.1% of T-DM1-treated patients experienced a grade 3 or 4 adverse event, compared with 39.4% of those given DTP. The proportion of patients needing a dose reduction was also lower in the T-DM1 than DTP group (11 vs 38%) and there were no deaths in either group while taking the study treatment.
After six cycles of treatment, patients receiving T-DM1 had significantly better scores on 13 variables of the EORTC QLQ-C30 and the breast cancer-specific EORTC-BR23 questionnaires than those given DTP. But 3 months after surgery, the HRQoL scores significantly favored DTP over T-DM1 for six variables and by 1 year HRQoL was similar between the study groups.
Hatschek et al conclude: “In selected patients with [HER2]-positive breast cancer, neoadjuvant treatment can be de-escalated with trastuzumab emtansine monotherapy.”
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