Effect of chemotherapy for acute myelogenous leukemia on hematopoietic and fibroblast marrow progenitors.

Since reduced marrow cellularity and prolonged pancytopenia following autologous bone marrow transplantation (ABMT) have been frequently observed in patients with acute myelogenous leukemia (AML) included in the AML10 GIMEMA/EORTC trial, the question was raised to what extent hematopoietic and microenvironmental progenitor cells were involved in these patients. Marrow hematopoietic progenitors were investigated by a short-term methylcellulose assay quantitating multipotent CFU-Mix, erythroid BFU-E and granulocyte-macrophage CFU-GM, as well as a long-term assay quantitating long-term culture-initiating cells (LTC-IC). The marrow microenvironment was studied by evaluating the incidence of fibroblastoid progenitors (CFU-F) and the capacity of stromal layers to support allogeneic hematopoietic progenitors. As compared to normal controls (n = 57), AML patients (n = 26) showed a statistically significant reduction of the mean (+/-s.e.m.) number of CFU-Mix (5.3 +/- 0.6 vs 0.8 +/- 0.2, P < or = 0.0001), BFU-E (68 +/- 5 vs 20 +/- 4, P < or = 0.0001), CFU-GM (198 +/- 11 vs 144 +/- 15, P < or = 0.008), and LTC-IC (302 +/- 46 vs 50 +/- 8, P < or = 0.001). The mean (+/-s.e.m.) incidence of marrow CFU-F was not significantly reduced as compared to normal controls (48 +/- 6 vs 52 +/- 7, P < or = 0.73). Seventeen AML stromal layers were tested for their capacity to support the growth of allogeneic hematopoietic progenitors. Seven samples failed to support any progenitor cell growth, seven had a significantly lower supportive activity as compared to normal stromal layers (13 +/- 5 vs 249 +/- 56, P < or = 0.002), whereas three cultures could not be analyzed due to contamination. In conclusion, induction and consolidation regimens used in AML patients of the AML10 protocol induce a markedly defective in vitro growth of primitive hematopoietic progenitors and a severe functional defect of marrow stroma. The association of hematopoietic with microenvironmental damage might play a key role in the delayed hematopoietic regeneration observed following ABMT in patients of the AML10 trial.

Use of granulocyte-macrophage colony-stimulating factor (GM-CSF) in combination with hydroxyurea as post-transplant therapy in chronic myelogenous leukemia patients autografted with unmanipulated hematopoietic cells.

BACKGROUND AND OBJECTIVE: Allogeneic bone marrow transplantation remains the only potentially curative treatment for CML, but more than 70% of patients will be ineligible for allogeneic marrow transplant either because they do not have a suitable HLA-matched related or unrelated donor or because they are more than 50 years old. Several experimental and clinical findings support a role for autologous stem cell transplantation (ASCT) in CML. It has been suggested that in the early phase following autografting the Ph-negative clone has a proliferative advantage over the Ph-positive clone. We hypothesized that post-transplant GM-CSF administration could reactivate the functional activity of quiescent normal progenitors and prolong the duration of the post-transplant proliferative advantage of Ph-negative over Ph-positive progenitors. In order to evaluate the effect of post-transplant GM-CSF administration, a pilot clinical study was performed in which CML patients resistant to IFN-alpha therapy were autografted with unmanipulated marrow or blood cells and given prolonged GM-CSF therapy post-transplant. METHODS: Five adult CML patients conditioned with the BAVC regimen were reinfused with either marrow (n = 2) or blood (n = 3) cells and given granulocyte-macrophage colony-stimulating factor (GM-CSF). Recombinant GM-CSF was initially administered at standard dosage (5 micrograms/kg/day) until a white blood cell count > or = 2 x 10(9)/L was achieved on two consecutive examinations, and thereafter at a low dose (1 microgram/kg/day) for 5 to 9 months. On a weekly basis, GM-CSF was discontinued and hydroxyurea (1,000 mg/d) was given for two days. RESULTS: Evidence of trilineage engraftment was observed in all cases. At autografting, 3 out of the 5 patients revealed 8-9% Ph-negative metaphases. During the initial phase of hematopoietic regeneration, direct cytogenetic analysis revealed 81% and 100% Ph-negative metaphases in two cases; nonleukemic hematopoiesis progressively decreased and was no longer detectable at +9 months. One patient showed cyclic Ph-negative hematopoiesis that appeared 3 months following autografting and peaked at +4 and +8 months. The fourth patient showed a low percentage (20%) of Ph-negative metaphases 1 month after ASCT, followed by a significant expansion of nonleukemic hematopoiesis, which could be detected up to month +13. No evidence of Ph-negative hematopoiesis could be detected in one patient. Three patients are in chronic phase 28, 30 and 31 months after autografting, respectively, and two patients evolved into blast crisis. INTERPRETATION AND CONCLUSIONS: This pilot study demonstrates that combined GM-CSF and hydroxyurea therapy seems to be effective in inducing and/or prolonging a transient period of Ph-negative hematopoiesis. The late appearance of Ph-negative hematopoiesis detected in two patients suggests an antileukemic activity of the combined GM-CSF/hydroxyurea therapy rather than an antileukemic effect of the conditioning regimen.

Probability of long-term disease-free survival for acute myeloid leukemia patients after first relapse: A single-centre experience.

BACKGROUND: Various polichemotherapy regimens, including either high- or intermediate-dose Ara-C, are generally utilized to reinduce remission in relapsed AML patients. After achieving second CR, bone marrow transplantation (either allogeneic or autologous) represents the treatment of choice for eligible patients, with the aim of prolonging remission duration and improving disease-free survival. PATIENTS AND METHODS: Fifty AML patients in first hematological relapse were treated with MEC regimen, consisting of a 6-day induction cycle [mitoxantrone 6 mg/m2/day, cytarabine (Ara-C) 1 g/m2/day and VP-16 80 mg/m2/day] followed by a 4-day cycle with the same drugs for patients achieving complete remission (CR); allogeneic or autologous bone marrow transplantation (BMT) were planned as post-consolidation treatment. RESULTS: Thirty-four patients (68%) achieved second CR, 3 (6%) died during induction and 13 were refractory. CR rate was significantly higher in patients with a first CR lasting > 6 months (82% vs. 41%, P < 0.001). Out of the 34 patients in CR after the 4-day cycle, 18 (53%) were not eligible to transplant and did not receive any further therapy and 16 (47%) received autologous (15 cases) or allogeneic (1 case) BMT at a median time of 2 months from second CR. Twenty-two patients relapsed after a median time of 6 months (range 1-31), 1 patient died from transplant-related toxicity and 11 are in continuous CR [7 out of 16 (44%) in the transplanted and 4 out of 11 (36%) in the non-transplanted group]. Overall survival and event-free survival for the 50 patients were 29% and 19% at 70 months, respectively. The disease-free survival for the 34 patients who obtained second CR is 29% projected at 69 months [41% at 69 months for 16 transplanted patients versus 18% at 49 months for the remaining 18 patients (P = 0.007)]. CONCLUSIONS: These results show that MEC followed by high-dose post-consolidation treatment is a promising approach in relapsed AML; however, alternative strategies are to be investigated for the relevant fraction of patients that, even achieving second CR, are not eligible for BMT.

Interleukin-2 for the treatment of advanced acute myelogenous leukemia patients with limited disease: updated experience with 20 cases.

Since 1988 we have treated a first group of 14 patients with recombinant interleukin-2 (rIL-2), which was previously published, and 6 other consecutive patients affected by refractory or relapsed acute myelogenous leukemia (AML) with >5% and < or = 30% bone marrow blasts, but not suitable for further chemotherapy. The rIL-2 schedule consisted of four 5-day high-dose cycles administered by continuous infusion with a 72-hour rest period between each cycle. Patients who achieved a response received a lower dose of subcutaneous rIL-2 maintenance treatment administered for 5 days every month. Following high-dose rIL-2, 11/20 patients (55%) obtained a complete remission (CR). Six remain in persistent CR after a median follow-up time of 50 months (9, 33, 49, 51, 52, 87 months, respectively); the length of remission is the longest in the natural history of the disease for each individual patient. One patient with stable disease at the end of rIL-2 induction is alive and well, with a stable number of blasts in the bone marrow, 18 months later. These 7 patients continue maintenance treatment with subcutaneous rIL-2. Close clinical and laboratory monitoring reveal that side effects are acceptable and no toxic deaths have been recorded. This update confirms the feasibility and antileukemic activity of high dose rIL-2 in advanced AML patients with limited disease, and suggests a potential clinical role of prolonged rIL-2 maintenance treatment.

Interleukin 2 treatment in acute myelogenous leukemia.

Significant clinical responses obtained with interleukin 2 (IL-2) in solid tumors such as renal cell cancer and malignant melanoma prompted the use of this immunomodulatory drug to verify its activity in hematological malignancies. Several preclinical experiments showed an activity of IL-2 against leukemic cell lines in cultures, particularly in acute myeloid leukemia (AML), while only episodically a proliferative stimulus of IL-2 on the growth of leukemic blasts has been observed. Based on these preclinical studies, in the past five years several phase I-II clinical trials have verified IL-2 activity in AML in advanced phase, both in patients with active disease and in patients in further complete remission (CR). Data obtained are difficult to evaluate due to the low number and the heterogeneity of patients treated, but encouraging results have been reported in patients with "limited" disease (bone marrow blastosis < 30%), showing an antileukemic activity of IL-2 alone. Different international phase III trials are ongoing in AML patients in I CR after autologous bone marrow transplantation (Roussel-Uclaf, Romainville, France) and in II CR after conventional chemotherapy (Roche SpA, Milan, Italy) to verify the efficacy of IL-2 in reducing the risk of relapse and prolonging disease-free survival.

ABMT for children AML: Italian experience. GITMO-AIEOP Groups.

We report data from an Italian survey on ABMT in 93 AML children less than 14 years in 1st or 2nd remission performed in 15 Centers. Different conditioning regimens have been employed: BAVC, an original schedule of chemotherapy; TBI plus Cy and/or other drugs (TBI + CHT); other high dose chemotherapy schedules (HD CHT). 62 patients have been transplanted in 1st CR; 38 have been conditioned with BAVC, 16 with TBI + CHT and 8 with HD CHT. Relapses were 21 in the BAVC group (DFS = 35% at 66 months), 5 in the TBI group (DFS = 61% at 48 months) and 5 in the HD CHT group; overall DFS is 39% at 66 months. 31 patients have been transplanted in 2nd CR; 14 were conditioned with BAVC and 16 with TBI + CHT; 6 patients relapsed in the first group, DFS is 56% at 50 months; in the second group 2 early deaths and 3 relapses occurred, DFS is 65% at 65 months. 1 patient in 2nd CR, conditioned with HD CHT, died during aplasia. Overall DFS is 59% at 65 months. Although no final conclusions concerning ABMT in AML children may be drawn from this retrospective study because of heterogeneity of population and methods, results obtained in 2nd CR are clearly better to those obtained with standard chemotherapy alone, confirming the role of ABMT in this high risk category of patients.