Determinants of lenalidomide response with or without erythropoiesis-stimulating agents in myelodysplastic syndromes: the HOVON89 trial

A randomized phase-II study was performed in low/int-1 risk MDS (IPSS) to study efficacy and safety of lenalidomide without (arm A) or with (arm B) ESA/G-CSF. In arm B, patients without erythroid response (HI-E) after 4 cycles received ESA; G-CSF was added if no HI-E was obtained by cycle 9. HI-E served as primary endpoint. Flow cytometry and next-generation sequencing were performed to identify predictors of response. The final evaluation comprised 184 patients; 84% non-del(5q), 16% isolated del(5q); median follow-up: 70.7 months. In arm A and B, 39 and 41% of patients achieved HI-E; median time-to-HI-E: 3.2 months for both arms, median duration of-HI-E: 9.8 months. HI-E was significantly lower in non-del(5q) vs. del(5q): 32% vs. 80%. The same accounted for transfusion independency-at-week 24 (16% vs. 67%), but similar in both arms. Apart from presence of del(5q), high percentages of bone marrow lymphocytes and progenitor B-cells, a low number of mutations, absence of ring sideroblasts, and SF3B1 mutations predicted HI-E. In conclusion, lenalidomide induced HI-E in patients with non-del(5q) and del(5q) MDS without additional effect of ESA/G-CSF. The identified predictors of response may guide application of lenalidomide in lower-risk MDS in the era of precision medicine. (EudraCT 2008-002195-10).

A functional study on the migration of human monocytes to human leukemic cell lines and the role of monocyte chemoattractant protein-1

In the present study the migration of human monocytes towards the supernatants of five different human myeloid leukemic cell lines, four different human lymphatic leukemic cell lines and blasts derived from three different patients with acute myeloid leukemia (AML) was studied and the role of monocyte chemoattractant protein (MCP)-1 was established with an ELISA assay. Large differences in migration of monocytes towards the leukemic cell supernatants were shown (variation of approximately 10 to 150% compared to positive control), but high amounts of monocyte migration was always restricted to myeloid leukemic cells (cell lines or patient blasts). MCP-1 turned out to play a major role in the migration, firstly since there was a direct correlation between the amount of migration and the concentration of MCP-1 in the supernatants, and secondly since the addition of anti-hMCP-1 was able to inhibit migration to background level in all cases. Cytotoxicity experiments with a MTT test using MCP-1-stimulated monocytes against two human myeloid leukemic cell lines showed no increase in cell death compared to unstimulated monocytes. It is concluded that monocyte migration towards leukemic cells is restricted to the myeloid lineage and is regulated by MCP-1, which is produced in different amounts by the leukemic cells. Besides, MCP-1 does not increase the direct toxic effects of monocytes on leukemic cells.

The role of BCL-2 and bax protein in monocyte-mediated apoptosis in human leukemic cell lines

Monocytes or monocyte-derived supernatants are able to kill leukemic cells via apoptosis, thereby preferentially effecting more mature leukemic cells. In the present study, the relationship between apoptosis and the apoptosis related proteins, bcl-2 and bax, was investigated in a number of human leukemic cell lines. Monocyte-derived supernatant induces extensive apoptosis in U937 myeloid leukemia cells and minor apoptosis in HL60 cells. No apoptosis was seen in four other cell lines (THP1, HL60-D3, KG1, and K562). The expression of bcl-2 and bax protein was determined in both groups of leukemic cell lines by flow cytometry (bcl-2 and bax) and Western blotting (bcl-2) at baseline level and after incubation with monocyte supernatant after different time periods. No clear relation was found between baseline bcl-2 or bax protein expression and the occurrence of apoptosis after incubation with monocyte supernatant. After different incubation time periods, no change was found in bcl-2 protein expression in U937 and K562 cells, whereas in KG1, HL60, and especially in THP1 cells, a significant decrease could be noticed. On the other hand, there was an increase in bcl-2 expression in HL60-D3 cells. Bax protein expression, measured at the same time points, remained essentially unchanged in HL60-D3 cells, decreased significantly in U937, HL60, and THP1 cells and slightly in K562 cells, and increased significantly in KG1 cells. Also, the ratio bax/bcl-2 decreased in HL60D3, but especially in U937 and HL60 cells, increased slightly in THP1 and KG1 cells, and remained essentially unchanged in K562 cells. Rh-tumor necrosis factor-alpha (TNF-alpha), the main mediator of monocyte mediated cytotoxicity, induced apoptosis in U937, HL60, and THP1 cells, thereby showing changes in bcl-2 expression similar to those found for monocyte derived supernatants. We concluded that in human leukemic cell lines, there is no relation between either bcl-2 or bax protein expression or the ratio of both, and apoptosis mediated by monocyte derived supernatant or TNF-alpha.

High-dose melphalan with re-infusion of unprocessed, G-CSF-primed whole blood is effective and non-toxic therapy in multiple myeloma

In order to shorten the pancytopenic period following high-dose melphalan 140 mg/m2 (HDM) treatment of multiple myeloma patients, we studied the effects of re-infusing granulocyte colony stimulating factor (G-CSF) [Filgrastim, Neupogen]-primed unprocessed whole blood. 30 patients with multiple myeloma were treated with HDM. One litre of blood after 5 or 6 days stimulation with G-CSF (10 micrograms/kg) was drawn, kept unprocessed for 1 day and re-infused 24 h after chemotherapy. Time to granulocyte recovery (> 0.5 x 10(9)/1) and platelet recovery (> 20 x 10(9)/1) were assessed as well as length of hospital stay, number of transfusions and antibiotic use. These 30 patients were compared with 20 historical control patients who were similarly treated but without stem cell support. The response rate was 75% (21/28) including a complete remission (CR) rate of 29% (8/28). Two early deaths due to Aspergillus pneumonia were observed. The median overall survival after HDM has not been reached after a median follow-up of 14 months. 10 patients showed progression at a median of 7 months. Currently, 23 patients are alive with a median follow-up time of 14 months. Haematological recovery was significantly faster in the study group as compared to the historical control group. The neutrophil count reached 0.5 x 10(9)/1 at a median of 14 days after infusion of 1 litre of unprocessed whole blood compared with 38 days in the historical control group. A platelet count of 20 x 10(9)/1 was reached at a median of 26 days compared with 36 days in the historical control group. Length of hospital stay decreased from a median of 43 to 18.5 days. The number of days with antibiotics was reduced from a median of 21 to 6 days. HDM is effective therapy for multiple myeloma. Toxicity of the regimen is considerably reduced by the use of G-CSF-stimulated unprocessed whole blood, an easy to perform and cheap technique to mobilise and collect stem cells.

G-CSF (filgrastim)-stimulated whole blood kept unprocessed at 4 degrees C does support a BEAM-like regimen in bad-risk lymphoma

The purpose of this study was to demonstrate the reconstitutive potential of granulocyte colony-stimulating factor (G-CSF) (filgrastim; Neupogen-primed unprocessed whole blood after myelotoxic therapy in bad-risk lymphoma. Nine patients with resistant lymphoma were treated with BAM: a BEAM regimen modified to a 72 h course consisting of BCNU 300 mg/m2 i.v. (day 1), Ara-C 3000 mg/m2 i.v. q 12 h (day 2) and melphalan 140 mg/m2 i.v. (day 3). After 5 days stimulation with G-CSF (10 micrograms/kg) 1l of blood was drawn, kept unprocessed for 3 days and reinfused 24 h after completion of chemotherapy. Back-up peripheral stem cells were available for all patients. The neutrophil count reached 0.5 x 10(9)/l at a median of 16 days (range 11-25) and a platelet count of 10 x 10(9)/l was reached at a median of 20 days (range 11-NR (not reached)). The median length of hospital stay was short in these patients with a median of 19 days (range 17-33). In three patients platelet transfusion independence did not occur before day 28. Those patients received their back-up stem cells. Antibiotics had to be used in two patients. The median number of reinfused CD34+ cells was 0.28 x 10(6)/kg (range 0.01-0.59). When more than 0.2 x 10(6)/kg CD34+ cells were reinfused the time to recovery was comparable to that observed after 'classical PBSCT'. In conclusion, the use of G-CSF-stimulated unprocessed whole blood is easy to perform and a cheap technique to mobilize and collect stem cells that can serve as a stem cell source after severe myelotoxic therapy in bad-risk malignant lymphoma.