- Adjuvant NeuVax combined with trastuzumab significantly reduced recurrence and prolonged disease-free survival (DFS) in patients with triple-negative breast cancer (TNBC).
- These patients currently have no effective adjuvant therapies to prevent recurrence.
Why this matters
- 60%-70% of patients with breast cancer have HER2 low-expressing tumours, and are not eligible for adjuvant trastuzumab.
- Nelipepimut-S+GM-CSF (NeuVax) is a HER2/neu peptide vaccine designed to act synergistically with trastuzumab.
- This study investigated whether the combination of trastuzumab and NeuVax reduced recurrence in patients who were clinically disease-free after standard treatment.
- There was no significant difference in recurrence rate or DFS in the overall study population (median follow-up 19.6 months).
- However, patients with TNBC (n=97) had significantly longer 24-month DFS in the vaccine arm (91.1% versus 69.9%, hazard ratio 0.26, 95% CI 0.09-0.90], P=0.023).
- The recurrence rate in TNBC patients was 7.5% and 26.7% in the vaccine and control groups, respectively (P=0.023).
- Safety was similar between groups.
- Patients had HER2 expression of 1-2+ by immunohistochemistry (IHC), and were either node-positive (with or without hormone receptor positivity), or node-negative with triple-negative receptor status. Specific categories of HLA expression also had to be present.
- Patients (n=275) were randomised 1:1 to receive trastuzumab+NeuVax (vaccine group) or trastuzumab+GM-CSF (control group). All patients received 1 year of trastuzumab as per label. NeuVax or GM-CSF was given every 3 weeks for 6 doses, then boosted every 6 months for 4 doses.
- The primary endpoint was DFS at 24 months; toxicity was also assessed.
- A confirmatory phase 3 study is required to investigate whether these results translate into a survival advantage.
The DFS results seen with the vaccine in TNBC patients were “really remarkable,” said Dirk Jäger, Heidelberg, Germany, the invited discussant.
- Sellas Life Sciences Group