Receptor for Hyaluronan-Mediated Motility (RHAMM [CD168]) peptide vaccination for patients with haematological malignancies: a phaseI/II pilot study

For all patients the BM blood was analysed before and after vaccination using microscopy and standard Fluorescence Activated Cell Sorter (FACS) analysis. Patients with MM were also examined for quantitative immunoglobulins and quantitative free light chains in serum and urine. The frequency of erythrocyte and platelet transfusions and the course of differential blood count were documented.

Response criteria were as following:
For patients with AML, the criteria by the World Health Organization (WHO) and the International Working Group (IWG) were followed as specified:
Complete Response (CR): reduction of blasts in the BM blood to less than 5%, in peripheral blood count: haemoglobin greater than 11 g/dl, neutrophils 1,500/mm^3 or more, platelets 100,000/mm^3 or more
Partial Response (PR): reduction of blasts in the BM blood of more than 50%, in peripheral blood count: haemoglobin greater than 11 g/dl, neutrophils 1500/mm^3 or more, platelets 100,000/mm^3 or more
Stable Disease (SD): no CR or PR
Progressive Disease (PD): increase of blasts in the BM blood by more than 50% or increase of WHO-classification or progress of transfusion requirements

For patients with MDS, the criteria by the WHO and the IWG were followed as specified:
CR: a complete response was defined as a normocellular with less than 5% blasts with normal maturation of all cell lines, with no evidence of dysplasia, in peripheral blood count: haemoglobin greater than 11 g/dl, neutrophils 1,500/mm^3 or more, platelets 100,000/mm^3 or more
PR: blasts decreased by 50% or more over treatment or a less MDS WHO classification than pretreatment, Haematological Improvement (HI): an improvement was defined as a decrease of at least of 50% in transfusion requirements, together with at least an improvement of one ot two cell lineages of the peripheral cell counts but not enough to qualify for a PR
SD: failure to achieve at least a HI, but no evidence of progression for at least two months
PD: increase of blasts in bone-marrow of more than 50% or increase of WHO-classification or progress of transfusion requirements

For patients with MM, the International Uniform Response Criteria according to Durie et. al. were applied:
Stringent Complete Remission (sCR): CR as defined below plus normal free light chain ratio and absence of clonal cells in the BM by immunohistochemistry or immunofluorescence
CR: negative immunofixation in the serum and urine
Very Good Partial Response (VGPR): serum and urine M-protein detectable by immunofixation but not on electrophoresis or 90% or greater reduction in serum M-protein plus urine M-protein less than 100 mg per 24 hours
PR: greater than or equal to 50% reduction of serum M-protein and reduction in 24-hour urinary M-protein by greater than or equal to 90% or to less than 200 mg per 24 hours
SD: no CR or PR
PD: increase of free light chains in serum or urine or of clonal plasma cells in bone-marrow of more than 25%

1. Assessment of toxicity of R3-peptide vaccination:
Side effects were documented according to Common Terminology Criteria for Adverse Events v3.0 (CTCAE). Before and three weeks after the fourth vaccination physical examination, body weight, ECOG performance score, laboratory tests (kidney and liver function tests, electrophoresis, electrolytes, C-Reactive Protein [CRP], Lactate Dehydrogenase [LDH], and coagulation tests), chest x-ray, echocardiography, electrocardiography, urine analysis, abdominal sonography and bone-marrow aspiration was performed. For patients with MM additionally quantitative immunoglobulins and quantitative assessment of free light chains in serum and urine were tested. Before each vaccination physical examination, laboratory tests (White Blood Cell [WBC] count, differential blood count, kidney and liver function tests, electrolytes, CRP, LDH, coagulation tests and urine analysis) were performed. To detect autoimmune reactions, we measured Thyroid Stimulating Hormone (TSH), free Triiodothyronine (fT3), free Thyroxine (fT4), as well as Antinuclear Antibody (ANA), CRP and Blood Sedimentation rate (BSG).

2. Interferon (IFN)-gamma and Granzyme B Enzyme-Linked Immunosorbent Spot (ELISpot) assays:
IFN-gamma and granzyme B ELISpot assays were performed as previously described to determine specific lysis of RHAMM (peptide) positive target cells according to the manufacturer's instructions (BD, San Diego, USA). We participated in an inter-laboratory test for ELISpot assays.

3. Tetramer staining:
The frequency of R3 specific CD8+ T lymphocytes was determined after eight days Mixed Lymphocyte Peptide Culture (MLPC) by staining with anti-CD8 antibody and HLA-A2/R3 tetramer R-Phycoerythrin (PE). HLA-A2/R3 tetramer PE was synthesised at the Lausanne Branch of the Ludwig Institute for Cancer Research. CD8+ T lymphocytes (0.5 - 1 x 10^6) stimulated with irradiated CD8- Antigen-Presenting Cells (APCs) in the presence of the R3 peptide were stained with HLA-A2/R3 tetramer PE 1 µg per test with respect to the peptide-Major Histocompatibility Complex (MHC) class I component in the dark and incubated for 40 minutes at room temperature. Thereafter, for four-color staining, 10 µl CD8 Peridinin Chlorophyll Protein (PerCP), 10 µl CD45RA Fluorescein Isothiocyanate (FITC) and 4 µl CCR7 APC (BD, Heidelberg, Germany) were added at 4°C for 20 minutes in the dark. As for six-color staining, the cells were stained with 1 µg HLA-A2/R3 tetramer PE and HLA-A2/WT1 tetramer PerCP per test with respect to the peptide-MHC class I component in the dark and incubated for 40 minutes at room temperature. Thereafter 5 µl CD8 APC-Cy7, 5 µl CD45RA APC (Invitrogen, Caltag, CA, USA), 10 µl CCR7 PE-Cy7, 10 µl CD27 FITC or CD28 FITC (BD, Heidelberg, Germany) were added at 4°C for 20 minutes in the dark. After washing once with Phosphate-Buffered Saline (PBS), stained cells were fixed with 1% formaldehyde (Sigma, Germany) and then analysed by flow cytometry. Whenever possible, at least 100,000 events were collected for analysis. Each sample was run with an appropriate isotype control to define the gate of positive cells. Analysis was performed on tightly gated lymphocytes to exclude dead cells and debris and on CD8+ T lymphocytes to evaluate responses to R3 peptide. Samples were defined as "tetramer positive" in case of an increase of specific R3-tetramer+/CD8+ T cells of more than 50% (if initial count was = 0.1%), or 25% increase (if initial count was greater than 0.1%). We participated in an inter-laboratory test for tetramer flow cytometry assays.