The levels of circulating tumor cells (CTCs) may have potential as a biomarker to track the response to treatment with Galena Biopharma's ($GALE) NeuVax (nelipepimut-S; E75), a therapeutic cancer vaccine, in patients with breast cancer. CTCs are cancer cells that have broken off the primary tumor and are floating free in the bloodstream, and may be the root cause of cancer metastasizing throughout the body.
The NeuVax shot, which triggers an immune response against the HER2 protein, is in a Phase III trial to prevent the recurrence of HER2-positive breast cancer. Preliminary results were presented at the 27th Annual Meeting of the Society for Immunotherapy of Cancer.
In the study, 26 patients treated with NeuVax had their CTC levels measured two or more times. In 16 of the patients, the levels of the CTCs decreased and the immune cells known as killer T-cells increased. Booster shots seemed to protect against the return of CTCs long-term, which may cut cancer recurrence.
Because higher levels of CTCs are a marker for cancer recurrence and shorter disease-free and overall survival, and because NeuVax reduces the levels of CTCs, this could suggest that CTC levels could indicate how well NeuVax is working and how effectively it is preventing a recurrence. However, the results haven't yet confirmed this correlation, so further studies or more data analysis would be needed to validate any role of CTCs as a marker of efficacy.
- read the press release
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