Use of palifermin for the prevention of high-dose methotrexate-induced oral mucositis.

BACKGROUND: Oral mucositis is a frequent problem after high-dose methotrexate (HD-MTX), impairing patient's quality of life, leading to higher rates of infections and delaying subsequent chemotherapy. This report describes the effect of palifermin in patients treated within the GMALL-B-ALL 2002 protocol containing HD-MTX who developed a severe mucositis in cycle A1/B1. PATIENTS AND METHODS: Ten patients, all with World Health Organization grades III-IV oral mucositis in cycles A1/B1, obtained palifermin with subsequent similar or identical cycles to reduce mucositis. Thus, patients serve as their own control for efficacy of palifermin. RESULTS: All 10 patients developed grades III-IV mucositis in cycles A1/B1 without palifermin, whereas only two of 10 developed grades III-IV mucositis in corresponding cycles A2/B2 with palifermin. Only four of 10 patients showed infections in the cycles with palifermin compared with 10 of 10 patients without palifermin. The duration of mucositits in patients who acquired a higher grade mucositis despite treatment with palifermin could be reduced from 12.9 days (median) without to 11 days with palifermin. The amount of i.v. opioid analgetics could be significantly reduced. CONCLUSION: Palifermin might reduce the incidence, severeness and duration of oral mucositis in HD-MTX-based chemotherapy and may influence clinical sequelae such as infection and quality of life.

Circulating angiopoietin-2 is a strong prognostic factor in acute myeloid leukemia.

Angiogenesis plays an important role in solid tumors and hematologic malignancies. The angiopoietins act as essential regulators in this process. We investigated the impact of circulating angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2) and soluble Tie2 (sTie2) on overall survival in patients with acute myeloid leukemia (AML). Ang-1, Ang-2 and sTie2 were measured in plasma samples from 68 AML patients and 11 controls using enzyme-linked immunosorbent assay. Circulating levels of Ang-2 and sTie2 (median (range): 1098.0 (361.4-4147.6) pg/ml and 3.40 (1.21-10.00) ng/ml, respectively) were significantly elevated in AML patients as compared to controls (307.9 (199.7-1225.0) pg/ml and 2.88 (1.71-3.29) ng/ml; P<0.001 and P=0.014). In a univariate Cox proportional hazards model, higher levels of Ang-2 and sTie2 were predictive of poor survival. In multivariate analyses, Ang-2 and cytogenetics proved to be independent prognostic factors, with a relative risk of 4.07 (95% confidence interval (CI) 1.88-8.81) and 2.70 (95% CI 1.25-5.81), respectively. The 3-year survival rate for AML patients with Ang-2 levels>/=1495.6 pg/ml was only 14.7% compared to 64.7% for those with Ang-2 levels<1495.6 pg/ml. These data provide evidence that circulating Ang-2 represents an independent prognostic factor in AML and may be used as a prognostic tool in the risk-adapted management of AML.

Correlation of neuropilin-1 overexpression to survival in acute myeloid leukemia.

Neuropilin-1 (NRP-1), a vascular endothelial growth factors and semaphorin receptor functioning as mediator of angiogenesis and neuronal guidance, is expressed by various solid tumors. The importance of NRP-1 in hematological malignancies such as acute myeloid leukemia (AML) remains to be elucidated. Therefore, we determined NRP-1 expression by immunohistochemical analysis of bone marrow biopsies of patients with newly diagnosed, untreated AML. The expression of NRP-1 was significantly increased in AML patients (n = 76; median 12.9 arbitrary units (a.u.)) as compared with controls (n = 38; median 2.75 a.u.). Survival was significantly poorer in patients with high (> median) versus low (< or = median) NRP-1 expression levels with 5-year overall survival rates of 16.9 versus 49.6% (P = 0.050). In conclusion, our data provide evidence of increased NRP-1 expression in AML with significant correlation to survival. Thus, NRP-1 might constitute a promising target for antileukemic and antiangiogenic treatment strategies in AML.

Thalidomide for the treatment of acute myeloid leukemia.

In analogy to solid neoplasms, accumulating data suggest the requirement of angiogenesis also for the development and progression of hematopoietic malignancies including acute myeloid leukemia (AML). Inhibition of increased microvessel density in bone marrow (BM) might be a promising target for pharmacological interventions aimed at reducing disease activity. Among the putative inhibitors of angiogenesis, thalidomide has demonstrated a considerable efficacy in myelodysplastic syndromes (MDS) and AML with overall response rates up to 56% and 25%, respectively. Responders experienced hematologic improvements with increased hemoglobin and platelet counts resulting in temporary transfusion independence. In AML, partial responses--defined as reduction of the leukemic blast cell infiltration of at least 50% in BM--occurred in four of 20 patients after one month of thalidomide administration in a previous phase I/II study. Additionally, we observed a long-term response in one AML patient of more than 20 months, meanwhile fulfilling the criteria of complete remission. The decrease in leukemic blast infiltration in BM of responders was accompanied by a significant reduction of the microvessel density. Overall adverse events caused by the drug consisted mainly of fatigue, constipation, skin rash and polyneuropathy with a tolerable dose of 200-400 mg p.o. per day. In conclusion, thalidomide as a single agent has significant anti-leukemic activity with some evidence for anti-angiogenic effects in BM, although the precise mechanism of action remains to be elucidated.

Overexpression of vascular endothelial growth factor (VEGF) and its cellular receptor KDR (VEGFR-2) in the bone marrow of patients with acute myeloid leukemia.

Vascular endothelial growth factor (VEGF) and its cellular receptor VEGFR-2 have been implicated as the main endothelial pathway required for tumor neovascularization. However, the importance of the VEGF/VEGFR-2 system for angiogenesis in hematologic malignancies such as AML remains to be elucidated. In 32 patients with newly diagnosed untreated AML, we observed by immunohistochemical analysis of bone marrow biopsies significantly higher levels of VEGF and VEGFR-2 expression than in 10 control patients (P <0.001). In contrast, VEGFR-1 staining levels in AML patients were in the same range as in the controls. Expression of VEGF and VEGFR-2 was significantly higher in patients with a high degree of microvessel density compared to those with a low degree (VEGF: P =0.024; VEGFR-2: P =0.040) and correlated well with bone marrow microvessel density (r(s)=0.566 and 0.609, respectively; P <0.001). Furthermore, in patients who achieved a complete remission following induction chemotherapy VEGFR-2 staining levels decreased into the normal range. In conclusion, our results provide evidence for increased expression of VEGF/VEGFR-2 of leukemic blasts and correlation with angiogenesis in the bone marrow of AML patients. Thus, VEGF/VEGFR-2 might constitute promising targets for antiangiogenic and antileukemic treatment strategies in AML.

[Angiogenesis in patients with hematologic malignancies]. / Angiogenese bei hämatologischen Neoplasien.

Angiogenesis in Patients with Hematologic Malignancies The importance of angiogenesis for the progressive growth and viability of solid tumors is well established. Emerging data suggest an involvement of angiogenesis in the pathophysiology of hematologic malignancies as well. Recently, we and others have reported increased angiogenesis in the bone marrow of patients with acute myeloid leukemia (AML) and normalization of bone marrow microvessel density when patients achieved a complete remission (CR) after induction chemotherapy. Tumor angiogenesis depends on the expression of specific mediators that initiate a cascade of events leading to the formation of new microvessels. Among these, VEGF (vascular endothelial growth factor), FGF (fibroblast growth factor) and angiopoietins play a pivotal role in the induction of neovascularization in solid tumors. These cytokines stimulate migration and proliferation of endothelial cells and induce angiogenesis in vivo. Recent data suggest an important role for these mediators in hematologic malignancies as well. Isolated AML blasts overexpress VEGF and VEGF receptor 2. Thus, the VEGF/VEGFR-2 pathway can promote the growth of leukemic blasts in an autocrine and paracrine manner. Therefore, neovascularization and angiogenic mediators/receptors may be promising targets for anti-angiogenic and anti-leukemic treatment strategies. The immunomodulatory drug thalidomide inhibits angiogenesis in animal models. Moreover, it has significant activity in refractory multiple myeloma. In a current phase II study for patients with primary refractory or relapsed multiple myeloma using a combination of thalidomide with hyperfractionated cyclophosphamide and dexamethasone (Hyper-CDT), we observed a partial remission in 12 of 14 evaluable patients (86%). Thus, this combination seems to be very potent. Furthermore, we evaluated the safety and efficacy of thalidomide in patients with AML not qualifying for intensive cytotoxic chemotherapy. 20 patients aged 58-85 (median 69) years were recruited to this phase I/II study and were treated with a dose of 200-400 mg per os daily for a duration of 1-40 (median 6) weeks, dependent on the individual tolerability of the drug. In 4 patients we observed a partial response (PR - defined as more than 50% reduction in leukemic blast infiltration in the bone marrow). This was accompanied by an increase in platelet counts and hemoglobin values. One additional patient showed a significant improvement of peripheral blood counts without fulfilling the criteria of a PR. In parallel, we observed a significant decrease in microvessel density in these 5 patients during treatment with thalidomide. In conclusion, thalidomide seems to have anti-angiogenic as well as anti-leukemic activity in AML. The VEGF/VEGFR-2 pathway seems to play an important role in AML. Therefore, receptor tyrosine kinase inhibitors like SU5416 or SU6668 are currently evaluated in the context of phase II studies in AML. We could recently induce a stable remission in a patient with second relapse of her AML refractory towards chemotherapy by administration of SU5416 (compassionate use), a tyrosine kinase inhibitor of VEGFR-2 and ckit. Current and future studies will clarify the role of anti-angiogenic treatment strategies in AML and other hematologic malignancies.

Stable remission after administration of the receptor tyrosine kinase inhibitor SU5416 in a patient with refractory acute myeloid leukemia.

The small molecule receptor tyrosine kinase (RTK) inhibitor SU5416 targets the vascular endothelial growth factor receptor 2 and the stem cell factor receptor c-kit. Herein is described the successful treatment of a 65-year-old woman with SU5416, in second relapse of acute myeloid leukemia (AML) and refractory toward standard chemotherapy regimens. After 12 weeks of treatment with SU5416, the blast cell counts (blood and bone marrow) decreased to undetectable levels and the peripheral blood cell counts normalized with the exception of the platelet count (50-80 x 10(9)/L [50-80 x 10(3)/microL]). The duration of the remission is longer than 4 months during maintenance therapy with SU5416. Microvessel density in the patient's bone marrow dropped from 33.4 to 12.3 microvessels/x500-field 8 weeks after SU5416 administration and remains in the normal range. This is the first report of a stable remission achieved after administration of the RTK inhibitor SU5416 in a patient with AML relapse.

Increased angiogenesis in the bone marrow of patients with acute myeloid leukemia.

The importance of angiogenesis for the progressive growth and viability of solid tumors is well established. In contrast, only few data are available for hematologic neoplasms. To investigate the role of angiogenesis in acute myeloid leukemia (AML), bone marrow biopsies from 62 adults with newly diagnosed, untreated AML (day 0) were evaluated. Further studies were done after the completion of remission induction chemotherapy (day 16 of induction chemotherapy, n = 21; complete remission, n = 20). Microvessels were scored in at least 3 areas (x500 field, 0.126 mm(2)) of the highest microvessel density in representative sections of each bone marrow specimen using immunohistochemistry for von Willebrand factor and thrombomodulin. Microvessel counts were significantly higher in patients with AML (n = 62) compared with control patients (n = 22): median (interquartile range) 24.0 (21.0-27.8)/x500 field vs 11.2 (10. 0-12.0)/x500 field, respectively (P <.001). On day 16 of induction chemotherapy, microvessel density was reduced by 60% (44-66) (P <. 001) in hypoplastic marrows without residual blasts, in contrast to only 17% (0-37) reduction in hypoplastic marrows with >/= 5% residual blasts (P <.001 for the difference between both groups). Bone marrow biopsies taken at the time of complete remission displayed a microvessel density in the same range as the controls. In conclusion, there is evidence of increased microvessel density in the bone marrow of patients with AML, which supports the hypothesis of an important role of angiogenesis in AML. Furthermore, these findings suggest that antiangiogenic therapy might constitute a novel strategy for the treatment of AML. (Blood. 2000;95:2637-2644)