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Niederwieser: Novartis Oncology Europe: Research Funding, Speakers Bureau; Amgen: Speakers Bureau. Hoffmann:Novartis Oncology Europe: Research Funding. Al-Ali:Celgene: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding. Hegenbart:Pfizer: Other: Travel grant; Janssen: Honoraria, Other: Travel grant. Sayer:Riemser Pharma: Consultancy. Hochhaus:BMS: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; ARIAD: Honoraria, Research Funding. Fischer:Novartis: Consultancy, Honoraria. Dreger:Novartis: Consultancy; Janssen: Consultancy; Gilead: Consultancy; Gilead: Speakers Bureau; Roche: Consultancy; Novartis: Speakers Bureau. Hiddemann:Roche: Membership on an entity's Board of Directors or advisory committees; Genentech: Other: Grants; Roche: Other: Grants.

Niederwieser: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Hoffmann:Novartis Oncology Europe: Research Funding. Krug:Sunesis; Clavis Pharma; usa Pharma, Catapult Cell Therapy, Gilead, Roche: Membership on an entity's Board of Directors or advisory committees; Sunesis: Speakers Bureau; Boehringer Ingelheim: Research Funding; Novartis; BMS; Roche; Boehringer Ingelheim; Bayer: Honoraria. Hegenbart:Janssen: Honoraria, Other: travel support. Pfirrmann:Novartis Pharma: Consultancy, Honoraria; BMS: Consultancy, Honoraria. Kraemer:TEVA: Other: travel support. Al-Ali:Celgene: Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding.

Background

Al-Ali: Novartis: Consultancy, Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Wolf:Bayer: Honoraria; Geo Pharma: Honoraria. Hochhaus:ARIAD Pharmaceuticals, Inc.: Research Funding. Maschmeyer:Celgene: Consultancy.

Off Label Use: Azacitidine is licensed in Germany for the treatment of adult patients with the following conditions, who are not eligible for haematopoietic stem cell transplantation: • intermediate-2 and high-risk myelodysplastic syndromes (MDS) according to the International Prognostic Scoring System (IPSS), • chronic myelomonocytic leukaemia (CMML) with 10-29% marrow blasts without myeloproliferative disorder, • acute myeloid leukaemia (AML) with 20-30% blasts and multi-lineage dysplasia,according to World Health Organisation (WHO) classification.. Wolf:Bayer: Honoraria; Geo Pharma: Honoraria. Sayer:Takeda: Other; Medac: Other. Al-Ali:Novartis: Consultancy, Honoraria, Research Funding; Celgene: Honoraria, Research Funding.

Al-Ali: Novartis: Consultancy, Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Wolf:Bayer: Honoraria; Geo Pharma: Honoraria.

Purpose:To define prognostic factors for overall survival in adult patients (pts) with relapsed acute myeloid leukemia (AML).

The incidence of acute myeloid leukemia (AML) is age-dependent with the majority of patients (pts) being older than 60 years at diagnosis. Treatment of these pts needs to be well balanced between sufficient efficacy and tolerable toxicity. Here, we report long term follow-up of the OSHO AML97 study. Pts with AML older than 60 years were registered after informed consent and received age-adapted intensive chemotherapy treatment (curative arm; induction therapy with AraC 2 g/m2iv day 1, 3, 5, 7 and mitoxantrone 10 mg/m2iv day 1 to 3 to induce complete remission (CR), followed by 2 consolidation courses with AraC 240 mg/m2iv day 1 to 5 and mitoxantrone 10 mg/m2iv day 1 to 2), low dose chemotherapy (palliative arm; idarubicin 10 mg po day 1 and either thioguanine 40 mg po day 1-5, or AraC 80 mg sc day 1-5 or etoposide 100mg po day 1-5) or supportive therapy (best supportive care including transfusions). A total of 618 pts were enrolled (curative arm n=471, palliative treatment n=115 and supportive therapy n=32 pts). In the curative arm, CR was obtained in 66.8% of pts. Treatment related mortality (TRM) was 11.2% after induction and 4.5% after consolidation I, respectively. Median overall survival for all pts in the curative arm was 12 months, event free survival (EFS) at 12 years was 0.11±0.02%. In multivariate analysis, cytogenetics at diagnosis was the most important prognostic factor for CR (p=0.001). With a median follow up of 10 years (range 0.1 - 11.8) probability of overall survival (OS) at 5 years was 0.48±0.11; 0.13±0.03; 0.10±0.04 and 0.08±0.03 for pts with favorable, normal, other and unfavorable cytogenetics. Median survival for pts treated with palliative chemotherapy was 54 days.

Treatment of elderly patients with AML remains challenging. While increasing doses of induction and consolidation chemotherapy have failed to improve outcome, efforts to decrease relapse rates using the graft-versus-leukemia effect have shown promising results in phase II studies. In the present analysis of the prospective OSHO 2004 study we evaluated the effect of post-induction hematopoietic cell transplantation (HCT) in comparison to conventional consolidation chemotherapy (CT) on outcome in elderly patients with AML.

In patients with relapsed acute myeloid leukemia (AML) > 60 years of age we analyzed age at relapse, interval from first complete remission (CR1) to relapse, cytogenetic risk at initial diagnosis, prior allogeneic stem cell transplantation (alloSCT) and FLT3/NPM1 mutational status as possible prognostic factors for overall survival (OS).After achieving CR1 more than 50% of elderly AML patients eventually relapse. Prognostic factors for OS are poorly defined in this patient population. For younger patients with relapsed AML a risk score has been described including age at relapse, interval from CR1 to relapse, cytogenetic risk at initial diagnosis and prior stem cell transplantation (SCT) as prognostic factors. We sought to investigate whether these are also prognostic factors in elderly patients with relapsed AML. In addition, we assessed the prognostic impact of FLT3- and NPM1 mutational status (wild-type (wt) or mutated (mut)) at diagnosis.In the ongoing multicenter OSHO trial #69 for AML patients > 60 years we evaluated data of all relapsed patients. Overall survival was calculated from the day of first relapse until the day of death using the Kaplan Meier method. Univariate analysis was performed to test for the influence of age at relapse, interval from CR1 to relapse, cytogenetic risk at initial diagnosis, prior alloSCT and FLT3/NPM1 mutational status. Subsequently, independent prognostic factors were defined in a multivariate analysis with age at relapse, time from CR1 to relapse, cytogenetic risk at initial diagnosis and prior alloSCT as covariates.From April 2005 until April 2013 904 patients were registered. 733 of these received intensive induction chemotherapy which resulted in CR1 in 447 (61%) pts. In this patient group 260 relapses were observed after a median interval, calculated from the day of CR1, for living patients of 2.7 years (range 0.1 to 7.5). Median age at relapse was 69 years (range 60 – 85) with 129 (49.6%) pts. being 60 to 68 years old, 102 (39.2%) pts. being 69 to 74 years old and 29 (11.1%) pts. being 75 to 85 years old. Median interval from CR1 to relapse was 0.58 years (0.07 – 6.28). 114 (43.8%) relapses occurred up to 6 months after CR1, 119 (45.8%) between 7 and 18 months after CR1 and 27 (10.4%) later than 18 months after CR1. Only five (1.9%) relapsed pts. showed good risk cytogenetics at diagnosis, whereas it was of intermediate risk in 159 (61.1%) pts., of poor risk in 68 (26.2%) pts. and unknown in 28 (10.8%) pts. Forty-one (15.8%) pts. had received prior alloSCT in CR1. Information on FLT3- and NPM1 mutational status at diagnosis was available in 194 (74.6%) pts. 110 (42.3%) pts. had FLT3/NPM1 wt/wt, 48 (18.5%) pts. had FLT3/NPM1 wt/mut, 23 (8.8%) pts. had FLT3/NPM1 mut/wt and 13 (5.0%) pts. had FLT3/NPM1 mut/mut.OS rate at 2 years of all relapsed pts. was 13 ± 2%. For patients younger than 69 years and for those 69 years of age or older OS rate at 2 years was 17 ± 4% and 9 ± 3%, respectively (p=0.03). The interval between CR1 and first relapse also affected 2 year-OS with 7 ± 3%, 15 ± 4% and 36 ± 12% for pts. with relapse up to 6 months, 7 to 18 months and later than 18 months after CR1, respectively ( 18 months: p=0.009). OS rate at 2 years was also influenced by cytogenetic risk at initial diagnosis with 17 ± 3% for pts. having good or intermediate risk cytogenetics and 3 ± 2% for those with poor risk cytogenetics (p< 0.0005). Prior alloSCT had a negative influence on OS. Two-year OS rate was 10 ± 5 and 13 ± 3% (p= .015) for patients with prior alloSCT vs. those without prior alloSCT, respectively. FLT3/NPM1 mutational status at diagnosis had no impact on OS.In univariate analysis age at relapse (p<0.04), interval from CR1 to relapse (p< 0.0005), cytogenetic risk at initial diagnosis (p<0.02) and prior alloSCT (p<0.02) were shown to be prognostic factors for OS, whereas FLT3/NPM1 mutational status was not significant (p=0.82). In multivariate analysis the same factors remained significant but only interval from CR1 to relapse (p<0.0005) and prior alloSCT (p=0.003) were independent.In AML patients >60 years in first relapse OS is poor. Longer interval from CR1 to relapse and no prior alloSCT are independent beneficial prognostic factors for OS. FLT3/NPM1 mutational status at diagnosis has no prognostic impact on OS.Wedding: Roche: Speakers Bureau; Amgen: Speakers Bureau; Chugai: Speakers Bureau; Janssen-Cilag: Speakers Bureau; Novartis: Speakers Bureau; Cephalon: Speakers Bureau; Prostarkan: Speakers Bureau; Pfizer: Speakers Bureau. Niederwieser:Novartis: Consultancy.

Hochhaus: Novartis: Consultancy, Honoraria, Research Funding, Travel Other; BMS: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Ariad: Consultancy, Honoraria.

Clinical trials on different cytarabine doses for treatment of AML provide evidence of a dose response effect, but also for increase toxicity after high dose AraC (HDAC). Pharmacokinetic measurements of cytarabine-triphosphate (AraC-CTP), which is the most relevant cytotoxic metabolite of AraC, have revealed its formation in leukemic cells to be saturated with infusion rates above 250 mg/m2/h, this being significantly lower than used in HDAC schedules. Methods: Based on a pharmacological model and encouraging results of a phase II study we conducted a prospective randomized multicenter clinical trial comparing the effects of two different application modes of AraC in patients up to 60 years with untreated newly diagnosed AML. Patients were randomized to receive AraC at two different infusion rates (IR) during induction and consolidation treatment: arm A/experimental: 1 × 2 g/m2/d AraC over 8 hours (IR 250 mg/m2/h) arm B/standard: 2 × 1 g/m2/d AraC over 3 hours (IR 333 mg/m2/h). Induction and first consolidation consisted of AraC (days 1, 3, 5, 7) in combination with an anthracycline (Idarubicine 12 mg/m2 or Mitoxantrone 10 mg/m2, days 1–3). The final dosage points (AraC day 7 and anthracycline day 3) were excluded from the second consolidation. The third consolidation consisted of either allogeneic or autologous stem cell transplantation or of chemotherapy identical to second consolidation. Results: From 02/97 to 04/02 419 patients were enrolled in the study. The present analysis is based on 361 eligible and evaluable patients with a median follow up of 7 years. CR was reached in 249/361 (69%; 95%CI: 65%–74%) patients. No statistically significant differences were detected between arms A and B with regard to CR-rate (69% vs 69%) or early death rate (11% vs 8%). Hematological recovery of median white blood cell count (WBC) > 109/l and median platelets (plt) > 50 × 109/l revealed no difference between arms A and B after induction (WBC day 22 vs 22, p=0,68; plt day 25 vs 26, p=0,41) and consolidation (WBC day 28 vs 27, p=0,07; plt day 42 vs 40, p= 0,58). The event free survival (EFS) after 5 years is 0,25 ± 0,03 % for all patients with an overall survival of 0,31 ± 0,03 % after 5 years. For the purposes of analysis, the 83 transplant patients (23 allogeneic MRD, 14 allogeneic MUD and 46 autologous) were censored at time of transplant. No statistically significant difference between arms A and B in regard to EFS (0,25 ± 0,04 vs 0,25 ± 0,04, p=0,99), relapse incidence (0,63 ± 0,06 vs 0,60 ± 0,06, p=0,89), overall survival (0,32 ± 0,04 vs 0,30 ± 0,04, p=0,44) and therapy associated mortality (0,18 ± 0,04 vs 0,17 ± 0,03, p=0,95) were detectable after adjustment of prognostic factors. An analysis of risk factors by multivariate cox regression model confirmed cytogenetics at diagnosis to be the most important risk factor for CR rate (p<10−6) and for EFS (p<10−6). Other significant prognostic factors for EFS evaluated in the multivariate analysis were de novo vs secondary AML (p=0,0001), WBC (continuous) (p=0,001), LDH (>1–4 × vs other ULN) (p=0,008) and FAB classification (FAB M0,6,7 vs FAB M1,2,4,5) (p=0,0005). EFS after 5 years shows a significant correlation to cytogenetics (p<10−6) with 0,71±0,1, 0,27±0,05, 0,20±0,06 and 0,03±0,03 for favorable, normal, other and unfavorable cytogenetic karyotype, respectively. Conclusion: We conclude that the application of AraC at the presumptive saturating infusion rate of 250 mg/m2/h results in comparable remission rates, toxicity, event free survival and overall survival as compared to the standard IR with 333 mg/m2/h.

Clinical trials on different cytarabine doses for treatment of AML provide evidence of a dose response effect, but also for increase toxicity after high dose AraC (HDAC). Pharmacokinetic measurements of cytarabine-triphosphate (AraC-CTP), which is the most relevant cytotoxic metabolite of AraC, have revealed its formation in leukemic cells to be saturated with infusion rates above 250 mg/m2/h, this being significantly lower than used in HDAC schedules.

AML patients with unfavourable cytogenetics generally have a poor outcome. Over the last decade a number of strategies to improving survival have been assessed by the East German Study Group (OSHO). Here, we analyse the results of three protocols (AML 93, AML 96 and AML 2002) for effects on outcome in younger patients (<60 years) with unfavourable cytogenetics.

Cytogenetic high risk AML (abn 3q26, abn 11q23, −5/5q-, −7/7q- and complex) has a dismal prognosis with a two year overall survival (OS) below 20% even in young patients. Attempts to improve survival by intensifying consolidation chemotherapy have so far failed. In the two OSHO protocols AML 96 and AML 2002, we investigated the role of allogeneic HCT in these patients. A total of 708 patients have been entered into the two studies between 1997 and the present. The first protocol (AML 96) compared two different schedules employing identical total dosages of intermediate AraC and Idarubicin. The second protocol (AML 2002) studied the role of two different induction therapies in patients failing to reach CR after the first induction therapy. In patients with cytogenetic high risk AML, the search for a donor (either familial or, if none available, then unrelated) was initiated as soon as possible. Allogeneic HCT was scheduled either after induction or after first consolidation therapy. HCT was performed after conditioning with cytoxan and 1200 cGy total body irradiation followed by GvH-D prophylaxis with cyclosporine and methotrexate. Of the 708 patients, 138 (19,5%) had high risk cytogenetics and 77 (55,8%) of these went into remission after one or two cycles of induction chemotherapy. Of these 77 patients, 54 were alive and in CR after the first consolidation therapy and were allocated to either related (n=12) or unrelated (n=21) HCT or, if no compatible donor was available, to a two courses of chemotherapy (n=21). Median age of the patients was 36 (range 17–51) years, 46 years (range 23–59) years and 49 (range 16–60) years for patients receiving related HCT, unrelated HCT and chemotherapy respectively. Data were analysed as intention to treat.LFS at 3 years was 67 ± 14% after related and 44 ± 14 % after unrelated HCT, but decreased to 11 ± 7% in patients receiving chemotherapy. Allogeneic HCT results were significantly better than the results of chemotherapy with p-values of 0.005 and 0.002 for related vs. chemotherapy and unrelated vs. chemotherapy respectively. Major differences in relapse incidences were seen between the three groups, with the lowest RI at 3 years after related HCT 26±0.13%, followed by unrelated HCT 48±15% and by chemotherapy 89±8% (p=0.003 and p=0,0006 for chemotherapy vs. related or unrelated HCT). Transplant related mortality at 3 years was 10±9%, 14±10% and 6±6% for patients receiving HCT from related donors, from unrelated donors and chemotherapy, respectively. Conclusions: From the results observed in the two prospective, multicenter studies we conclude that consolidation with allogeneic HCT is superior to chemotherapy in younger patients with high risk cytogenetics. While no differences in TRM were seen between the three treatment arms, a lower relapse incidence after related and unrelated HCT contributed to the improved OS.

AML patients with unfavourable cytogenetics generally have a poor outcome. Over the last decade a number of strategies to improving survival have been assessed by the East German Study Group (OSHO). Here, we analyse the results of three protocols (AML 93, AML 96 and AML 2002) for effects on outcome in younger patients (<60 years) with unfavourable cytogenetics. Methods: Unfavourable cytogenetics, defined as abn 3q26, -5/5q-, -7/7q-, abn 11q23 or a multiaberrant clone were present in 20 (12,3%), 76 (20,5%) and 60 (26,3%) patients from the AML 93/96/2002 respectively. In the AML 93 protocol, therapy consisted of double induction (Idarubicin and standard dose AraC 3+7), followed by consolidation (Mitoxantron, Etoposide) and re-induction (Idarubicine + high dose AraC). In both AML 96 and AML 2002, a single course of induction therapy (intermediate dose AraC and Idarubicine 3+7) was repeated as the first consolidation for all patients achieving CR. In AML 96, patients in PR after the first induction received intermediate dose AraC and Mitoxantrone as a 2nd induction therapy. In AML 2002, both non-responders and those achieving PR were randomized between the same induction therapy or a more intensive regime (Mitoxantrone, Fludarabin and intermediate dose AraC). Results: Of all patients with unfavourable cytogenetics (n=156), 40%, 50%, and 65% achieved CR in the AML 93, 96 and 2002 studies respectively, with no statistically significant difference between the CR rates in the three studies (p=0,19). OS and EFS were analyzed both with and without censoring HCT. OS and EFS in patients censored at the time of transplant was not different between the three AML studies although intensity of chemotherapy differed widely (standard, intermediate and high dose AraC). The same analysis performed without censoring allogenic HCT revealed OS at 3 years of 10% for the AML 93, 14% for the AML 96 and 34% for the AML 2002 study (log rank p < 10 -2). EFS at 3 years was 9%, 10% and 32% in the AML 93, 96 and 2002 respectively (log rank p < 0,10-3). In AML 96, 32% of the patients with unfavourable karyotype underwent HCT, 40 % of these in CR1. In AML 2002, 60% of such patients were transplanted and 75% of them were in CR1. The interval from diagnosis to HCT decreased from median 204 (range 142–329) days in the AML 96 to median 125 (range 47–321) days in the AML 2002 (p=0,001). This decrease was associated with fewer cycles of chemotherapy prior to transplant: Patients in the AML 96 protocol received a median of 3 courses (range 2–4) and those in AML 2002 a median of 2 courses (p= 0,002). Conclusion: We conclude that intensity of induction and consolidation chemotherapy is not crucial for CR rate, OS or EFS in patients with unfavourable karyotype,. Improvement in OS and EFS was observed only using HCT as early as possible after CR1.

Cytogenetic high risk AML (abn 3q26, abn 11q23, −5/5q-, −7/7q- and complex) has a dismal prognosis with a two year overall survival (OS) below 20% even in young patients. Attempts to improve survival by intensifying consolidation chemotherapy have so far failed. In the two OSHO protocols AML 96 and AML 2002, we investigated the role of allogeneic HCT in these patients. A total of 708 patients have been entered into the two studies between 1997 and the present. The first protocol (AML 96) compared two different schedules employing identical total dosages of intermediate AraC and Idarubicin. The second protocol (AML 2002) studied the role of two different induction therapies in patients failing to reach CR after the first induction therapy. In patients with cytogenetic high risk AML, the search for a donor (either familial or, if none available, then unrelated) was initiated as soon as possible. Allogeneic HCT was scheduled either after induction or after first consolidation therapy. HCT was performed after conditioning with cytoxan and 1200 cGy total body irradiation followed by GvH-D prophylaxis with cyclosporine and methotrexate. Of the 708 patients, 138 (19,5%) had high risk cytogenetics and 77 (55,8%) of these went into remission after one or two cycles of induction chemotherapy. Of these 77 patients, 54 were alive and in CR after the first consolidation therapy and were allocated to either related (n=12) or unrelated (n=21) HCT or, if no compatible donor was available, to a two courses of chemotherapy (n=21). Median age of the patients was 36 (range 17–51) years, 46 years (range 23–59) years and 49 (range 16–60) years for patients receiving related HCT, unrelated HCT and chemotherapy respectively. Data were analysed as intention to treat.LFS at 3 years was 67 ± 14% after related and 44 ± 14 % after unrelated HCT, but decreased to 11 ± 7% in patients receiving chemotherapy. Allogeneic HCT results were significantly better than the results of chemotherapy with p-values of 0.005 and 0.002 for related vs. chemotherapy and unrelated vs. chemotherapy respectively. Major differences in relapse incidences were seen between the three groups, with the lowest RI at 3 years after related HCT 26±0.13%, followed by unrelated HCT 48±15% and by chemotherapy 89±8% (p=0.003 and p=0,0006 for chemotherapy vs. related or unrelated HCT). Transplant related mortality at 3 years was 10±9%, 14±10% and 6±6% for patients receiving HCT from related donors, from unrelated donors and chemotherapy, respectively.

Objectives: Hematopoietic growth factors are essential in accelerating myeloid reconstitution and reducing treatment morbidity of hematological and non-hematological malignant diseases. In order to understand in more detail the effect of G-CSF on myeloid regeneration, patients (pts) with AML (excluding APL) enrolled in the OSHO AML96 and AML97 trials were analyzed with respect to cytogenetic risk factor, G-CSF treatment and myeloid recovery. Methods: A total of 603 eligible pts from 19 centers were included in this retrospective study. The diagnosis of AML was centrally reviewed and cytogenetic analyses performed in accredited laboratories. Pts were grouped in favorable (ie CBF leukemias: t(8;21); inv16) intermediary (normal or others) and unfavorable (−5/5q-; −7/7q-; abn11q23; inv3, or complex) cytogenetic risks. Treatment consisted of 8gm/m2 Ara-C for induction (1gm/m2 q12h or 2gm/m2/d on d1,3,5,7) in combination with an anthracycline (idarubicine 12mg/m2/d in patients <60a or mitoxantrone 10mg/m²/d on d1-3 in patients >60a). G-CSF was started on day 10 after chemotherapy and continued until myeloid reconstitution in 394 pts from 10 centers. Results: After induction chemotherapy, G-CSF accelerated leukocyte recovery (>1x109/L) by 3 days (median 21d vs 24d; n=560). The effect of G-CSF was, however, more evident in the favorable cytogenetic risks (19d vs 25d; p<0.0001), followed by the intermediate (21d vs 24d; p<0.0001) and not significant in the unfavorable (22d vs 25d; p=0.29). In pts without G-CSF treatment, myeloid reconstitution was identical in the 3 cytogenetic groups (25d vs 24d vs 25d). Subsequently, only pts with complete remission after the first induction treatment were selected (n=302) and the duration of leukopenia analyzed with respect to G-CSF and cytogenetic findings. Again, G-CSF shortened the duration of leukopenia in all 3 cytogenetic groups, and the effect was clearly influenced by cytogenetics. The median duration to myeloid recovery in pts with CBF AML was 25d without G-CSF and 19d with G-CSF treatment (p=0.0001). Pts with intermediate cytogenetics recovered after a median of 24d without and after 21d with G-CSF (p= 0.0003). The outcome in pts with unfavorable karyotype was similar: 25d without and 21d with G-CSF treatment, respectively (p=0.004). However, whereas no difference in myeloid reconstitution was observed between the 3 cytogenetic groups without G-CSF administration, clear differences were seen in G-CSF treated pts between the CBF AML and the others (6d vs 3-4d; p<0.0007). In a multivariate analysis, the cytogenetic risk group (p=0.002), remission state after first induction (p=0.004), and G-CSF administration (p<0.0001) independently proved to influence myeloid regeneration. Conclusion: We conclude that the accelerating effect of G-CSF on myeloid recovery correlates with cytogenetic findings and is greater in CBF AML than in intermediary or unfavorable cytogenetics. The mechanisms underlying this effect are currently unknown, but might involve increased susceptibility of normal hematopoiesis to G-CSF in CBF AML, or might rely on the differentiating effect of G-CSF on CBF AML.

Objectives:Hematopoietic growth factors are essential in accelerating myeloid reconstitution and reducing treatment morbidity of hematological and non-hematological malignant diseases. In order to understand in more detail the effect of G-CSF on myeloid regeneration, patients (pts) with AML (excluding APL) enrolled in the OSHO AML96 and AML97 trials were analyzed with respect to cytogenetic risk factor, G-CSF treatment and myeloid recovery.