Abstract
In pre-clinical models, the only two chemotherapy drugs which have been demonstrated to directly reduce the number of myeloid-derived suppressor cells (MDSCs) are gemcitabine and 5-fluorouracil. Here we analyze the dynamics of MDSCs, phenotyped as Lin-DR-CD11b+, in patients with advanced pancreatic cancer receiving the combination of gemcitabine and capecitabine, a 5-FU pro-drug. We found no evidence that gemcitabine and capecitabine directly reduce MDSC% in patients. Gemcitabine and capecitabine reduced MDSCs in 42% of patients (n = 19) and MDSC% fell in only 3/9 patients with above-median baseline MDSCs. In 5/8 patients with minimal tumour volume change on treatment, the MDSC% went up: increases in MDSC% in these patients appeared to correlate with sustained cancer-related inflammatory cytokine upregulation. In a separate cohort of 21 patients treated with gemcitabine and capecitabine together with concurrently administered GV1001 vaccine with adjuvant GM-CSF, the MDSC% fell in 18/21 patients and there was a significant difference in the trajectory of MDSCs between those receiving GV1001 and GM-CSF in combination with chemotherapy and those receiving chemotherapy alone. Thus, there was no evidence that the addition of low-dose adjuvant GM-CSF increased Lin-DR-CD11b+ MDSC in patients receiving combination chemoimmunotherapy. 9/21 patients developed an immune response to GV1001 and the MDSCs fell in 8 of these 9 patients, 6 of whom had above-median pre-vaccination MDSC levels. A high pre-vaccination MDSC% does not preclude the development of immunity to a tumour-associated antigen.
Original language | English |
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Pages (from-to) | 175-83 |
Number of pages | 9 |
Journal | Cancer Immunology Immunotherapy |
Volume | 63 |
Issue number | 2 |
DOIs | |
Publication status | Published - Feb 2014 |
Keywords
- Antigens, CD11b
- Antineoplastic Combined Chemotherapy Protocols
- Deoxycytidine
- Fluorouracil
- Granulocyte-Macrophage Colony-Stimulating Factor
- Humans
- Interleukin-6
- Myeloid Cells
- Pancreatic Neoplasms
- Peptide Fragments
- Telomerase
- Vaccination