Stem Cell Procurement

Fludarabine as a risk factor for poor stem cell harvest, treatment-related MDS and AML in follicular lymphoma patients after autologous hematopoietic cell transplantation


Fludarabine is an effective treatment for follicular lymphoma (FL), but exposure to it negatively impacts stem cell mobilization and may increase the risk of subsequent myelodysplastic syndrome and acute myelogenous leukemia (t-MDS/AML). We hypothesized that the risk that fludarabine imparts to stem cell mobilization and t-MDS/AML would be affected by dose or timing. All patients with FL treated at Cleveland Clinic from 1991 to 2007 with autologous hematopoietic cell transplantation were evaluated. Recursive partitioning analysis was used to explore associations of fludarabine and mitoxantrone dose and timing with poor stem cell harvest and t-MDS/AML. We identified 171 patients, of whom 52 previously received fludarabine. Patients exposed to fludarabine prior to auto-HCT were more likely to require >5 days of leukapheresis (P<0.001) and second stem cell mobilization (P<0.001), especially at a cumulative dose >150 mg/m2. Univariable risk factors for t-MDS/AML included the number of chemotherapy regimens before auto-HCT, the need for >5 days of leukapheresis to collect CD34+ cells and fludarabine exposure in a dose-dependent manner, particularly when >500 mg/m2. A cumulative dose of fludarabine >150 mg/m2 increases the risk for poor stem cell harvests and any exposure increases the risk of t-MDS/AML, with the greatest risk being at doses >500 mg/m2.


Long-term complications of treatment for lymphoma are being recognized with increased frequency. Treatment-related myelodysplastic syndrome or acute myelogenous leukemia (t-MDS/AML) is a particularly devastating complication. The cumulative incidence of t-MDS/AML has been estimated at approximately 10%.1 Exposure to fludarabine may increase the risk of subsequent t-MDS/AML.2, 3, 4, 5

Fludarabine is an effective treatment for follicular lymphoma (FL). In combination with mitoxantrone and dexamethasone as frontline therapy, fludarabine induced at least a PR in 96% of patients and a CR in 68%.6 The fludarabine, mitoxantrone and dexamethasone (FND) regimen is generally well tolerated, with little short-term toxicity other than myelosuppression and increased risk of infection.7 Despite evidence for superior remission rates compared with doxorubicin-based chemotherapy, fludarabine is usually relegated to the treatment of relapsed and refractory FL.6, 8

The role of fludarabine in the treatment of FL is further obscured by the adverse effect that fludarabine exerts on stem cell mobilization.2, 9, 10 High-dose chemotherapy followed by autologous hematopoietic cell transplant (auto-HCT) provides long progression-free survival in a significant proportion of patients.11, 12 We previously showed that the same factors predictive of poor stem cell mobilization also predict for t-MDS/AML.13 However, we were unable to identify fludarabine as a cause of either a poor stem cell harvest or a t-MDS/AML in that analysis of both Hodgkin's and non-Hodgkin's lymphoma patients.

Therefore, we sought to clarify the risk that fludarabine imparts to stem cell mobilization and t-MDS/AML in a population limited to patients with FL. We hypothesized that the dose and timing of fludarabine might be important determinants of subsequent stem cell damage.

Materials and methods

From 1991 through 2007, 193 adult patients with FL underwent auto-HCT at the Cleveland Clinic. All patients had FL as defined by the revised European–American classification of lymphoid neoplasms.14 A retrospective chart review identified 179 of those patients who were treated with a uniform preparative regimen of BU, CY and etoposide. Eight patients were excluded from evaluation because they received BM in addition to mobilized blood cells with their auto-HCT. Thus, 171 patients were analyzed. Data regarding treatment received prior to auto-HCT was obtained from medical records provided to us by referring physicians either retrospectively or at the time of the initial patient evaluation. Following auto-HCT, patient outcome data were captured prospectively and accessed through the Cleveland Clinic Transplant Center Unified Transplant Database. All patients were treated on clinical trials approved by the Institutional Review Board of the Cleveland Clinic Foundation and all patients gave signed, informed consent.

Stem cell harvesting and processing

PBSCs were mobilized with G-CSF 10 mcg/kg/day (n=74; 43.3%) for up to 10 days beginning 5 days before leukapheresis, or G-CSF plus etoposide 2 g/m2 (n=86; 50.3%), G-CSF plus CY (CTX) (n=5; 2.9%), G-CSF plus plerixafor (n=3; 1.8%), G-CSF plus CTX and mitoxantrone (n=2; 1.2%), or G-CSF plus IL-3 (IL-3) (n=1; 0.6%). Stem cell harvesting began when the WBC count recovered to >5000/μL after the chemotherapy-induced nadir.

After mobilization by any method, patients underwent standard leukapheresis on a COBE Spectra (Gambro; Lakewood, CO, USA) machine for 5 days or until they had provided enough stem cells. Before October 1995, a minimum total nucleated cell dose (TNC) of 10 × 108/kg was required. After October 1995, the minimum CD34+ stem cell dose needed to proceed to auto-HCT was 2 × 106/kg. Patients failing to achieve the minimum TNC or CD34+ stem cell dose in 5 days were mobilized again by a different method. Those patients initially mobilized with G-CSF alone were subsequently mobilized with chemotherapy plus G-CSF, and those initially mobilized with chemotherapy were subsequently mobilized with high-dose G-CSF, 16–30 mcg/kg/day, alone. Leukapheresis was then attempted until the minimum TNC or CD34+ stem cell dose was achieved, or until the treating physician deemed enough stem cells had been obtained. Those patients failing second mobilization, or not collecting the minimal dose of TNC or CD34+ stem cells in the absence of a BM harvest, did not proceed to auto-HCT and are not included in this study.

Preparative regimens

All patients in this analysis were treated with a preparative regimen of oral BU 1 mg/kg every 6 h for 14 doses, etoposide 50–60 mg/kg by continuous infusion over 2 days and CY 60 mg/kg i.v. over 2 h on two consecutive days. The details of administration and supportive care have been previously described.15 G-CSF was administered to all patients to accelerate neutrophil recovery beginning on either the day following stem cell infusion or 5 days following infusion.16


Following auto-HCT, patients were followed either at the Cleveland Clinic or at their local oncologist's office. Data regarding relapse, survival and long-term complications were solicited at regular intervals from the local oncologist's office and verified at the Cleveland Clinic whenever possible.

The diagnosis of t-MDS/AML was made on the basis of the histological criteria of the FAB classification system17 and confirmed by the demonstration of clonal cytogenetic abnormalities whenever possible.

Statistical analysis

The incidence of t-MDS/AML was estimated using the cumulative incidence method. Cox proportional hazards analysis was used to identify univariable risk factors for t-MDS/AML. The following variables were assessed as potential risk factors: gender, age, ECOG performance status, number of prior chemotherapy regimens, prior radiation therapy, prior MoAb exposure, stage, prior exposure to fludarabine (dose and timing), prior exposure to mitoxantrone (dose and timing), BM involvement at transplant, International Prognostic Index (IPI), bulk of largest mass, disease status, elevated lactate dehydrogenase, mobilizing regimen, days of leukapheresis, TNC dose and CD34+ dose. Results are summarized as the hazard ratio (HR), 95% confidence interval for the HR and corresponding P-value. The primary focus of this investigation was risk from fludarabine, adjusted for mitoxantrone. Therefore, fludarabine and mitoxantrone results are presented, whether or not they are significant, whereas other study variables are shown only if they are significant. Multivariable risk factors could not be assessed due to the small number of t-MDS/AML events.

Recursive partitioning analysis (RPA) was used to explore associations of fludarabine dose and timing and mitoxantrone dose and timing with t-MDS/AML. An RPA cutpoint of >500 mg/m2 was found for fludarabine dose, so results for fludarabine dose vs t-MDS/AML are summarized three ways: any fludarabine exposure vs none, >500 vs 0–500 mg/m2 (RPA cutpoint) and per 50 mg/m2 increase (continuous variable). No cutpoints were identified for mitoxantrone dose, so mitoxantrone dose is analyzed as any exposure vs none. No cutpoints were identified for timing of fludarabine or mitoxantrone, so both are summarized as no exposure vs exposure within 3 months prior to transplant vs exposure >3 months prior to transplant. The rationale for selecting these cutpoints is to assess whether fludarabine or mitoxantrone increases the risk of t-MDS/AML when given as a part of salvage therapy immediately before stem cell collection.

Forty-three patients in this study required >5 days of leukapheresis, which has been shown in this study and in other studies to be a risk factor for t-MDS/AML. Therefore, to indirectly assess the association of fludarabine with t-MDS/AML while adjusting for mitoxantrone, we assessed fludarabine dose and timing and mitoxantrone dose and timing as risk factors for >5 days of leukapheresis. Again, RPA was used to determine whether fludarabine or mitoxantrone dose or timing was associated with the need for >5 days of leukapheresis. Two univariable risk factors were identified with RPA: fludarabine dose >150 mg/m2, and any mitoxantrone <27 months prior to transplant. Fludarabine >150 mg/m2 was then assessed as a risk factor for >5 days of leukapheresis in four ways: unadjusted for mitoxantrone, adjusted for three groups of mitoxantrone dose (none vs 10–40 vs >40 mg/m2), adjusted for continuous mitoxantrone dose (per 10 mg/m2 increase) and adjusted for mitoxantrone timing (<27 months; RPA cutpoint). These analyses were done using logistic regression analysis. Results are summarized as the odds ratio (OR), 95% confidence interval for the OR and corresponding P-value.

All statistical tests were two-sided, and P0.05 was used to indicate statistical significance. Analyses were done using SAS software (SAS Institute Inc., Cary, NC, USA).


The characteristics of the 171 patients are listed in Table 1. We identified six patients with t-MDS/AML. Four patients fulfilled the FAB criteria for MDS, while two fulfilled the criteria for AML.17 Cytogenetic analysis was available after auto-HCT for these six patients. A normal karyotype was identified in three patients, a complex karyotype in two patients and monosomy 7 in one patient. Five of the six patients who developed MDS/AML had been previously treated with fludarabine and one had not. With a median follow-up of 57.9 months for survivors, 3.5% of patients have developed t-MDS/AML. Cumulative incidence of t-MDS/AML at 1, 5 and 10 years was 0.6%, 3.5% and 7.3%, respectively.

Table 1 Patient characteristics

There were 43 patients (25.1%) who required more than 5 days of leukapheresis to yield an adequate number of CD34+ stem cells. In total, there were 26 patients who failed to mobilize enough stem cells with the initial attempt and were then mobilized with an alternative regimen (salvage mobilization).

Fludarabine was administered to 52 patients at a median of 279 days (range 39–1443 days) before auto-HCT. The median cumulative dose of fludarabine was 450 mg/m2 (range 80–875 mg/m2). Fludarabine was administered in combination with mitoxantrone in 21 of these patients. Patients exposed to fludarabine at any time prior to auto-HCT were more likely to require >5 days of leukapheresis (P<0.001) and more likely to require salvage stem cell mobilization (P<0.001).

Univariable risk factors for t-MDS/AML included the number of chemotherapy regimens administered before auto-HCT, the need for >5 days of leukapheresis to collect CD34+ cells and fludarabine exposure: any, >500 mg/m2 and increase per 50 mg/m2 increment (Table 2). Multivariable analysis was not performed for risk of t-MDS/AML given the low number of total events.

Table 2 Univariable risk factors for treatment-associated myelodysplastic syndrome or AML in patients with follicular lymphoma treated with auto-HCT

As mitoxantrone has been implicated as a potential cause of t-MDS/AML,18 we sought to account for prior mitoxantrone exposure in our analysis. The median cumulative dose of mitoxantrone received was 60 mg/m2 (range 20–60 mg/m2). In univariable and multivariable logistic regression analyses, fludarabine dose >150 mg/m2 was found to be a risk factor for >5 days of leukapheresis, whether adjusted or unadjusted for mitoxantrone (see Table 3).

Table 3 Fludarabine dose and the risk of >5 days of leukapheresis adjusted for mitoxantrone dose


Fludarabine is an effective agent for treating FL, and is usually given as a salvage agent for relapsed or refractory disease. The dose of fludarabine in the commonly used FND regimen is 25 mg/m2 daily for 3 days.7 Our study suggests that cumulative doses of fludarabine >150 mg/m2, or more than two cycles of FND, increase the risk for poor stem cell harvests and that any exposure increases the risk of t-MDS/AML, with the greatest risk accrued at doses >500 mg/m2. This effect is independent of the number of prior chemotherapy cycles administered and mitoxantrone exposure.

In a population of patients with chronic lymphocytic leukemia, Tournilhac et al.10 showed no impact of fludarabine timing on successful mobilization. However, the median time from last exposure to fludarabine and stem cell harvesting was only about 178 days (range 69–377 days) in their study. In our study, the median time to last fludarabine exposure was 279 days (range 39–1443 days), reflecting differences in the study populations. With a longer range of previous exposure, we identified a significant adverse effect of fludarabine when it was administered less than 11.9 months prior to auto-HCT.

A study of 41 patients with a variety of lymphoproliferative disorders found no significant effect of fludarabine on stem cell mobilization.19 However, only 34% of patients had a successful first harvest and they included patients who subsequently had a successful harvest in their definition of those who were successfully harvested for analysis. Moreover, the patients in this study were mobilized less often with G-CSF alone compared with the patients in our study (15% vs 43%), suggesting that chemotherapy plus G-CSF may overcome the adverse effect of fludarabine on mobilization. Nonetheless, the adverse effect of fludarabine on subsequent t-MDS/AML persists.

In contrast to our results, Sacchi et al.20 reported 12 cases of t-MDS/AML in an analysis of 563 previously untreated non-Hodgkin's lymphoma (NHL) patients followed for a median of 62 months. Although there was a trend toward an increased relative risk for secondary malignancy in the fludarabine treated group, it was not statistically significant (P=0.074), and no association between fludarabine and the development of t-MDS/AML was identified. We reported similar results when we analyzed a heterogeneous population of lymphoma patients,13 but we found fludarabine to be a significant risk factor for t-MDS/AML when we restricted our current analysis to patients with FL.

Laurenti et al.21 evaluated the role of pre-transplant chemotherapy in the incidence of secondary malignancies after auto-HCT for indolent lymphoma. Out of 142 patients, 3 patients developed t-MDS/AML and use of fludarabine was found to be an independent risk factor for development of t-MDS/AML in both univariable and multivariable analyses. Also, similar to our findings, Bowcock et al.22 identified a dose effect of fludarabine on the risk of t-MDS/AML.They also observed that the only patients in their series to develop t-MDS/AML were those treated with both fludarabine and CY. Fludarabine has been shown to potentiate the cytotoxicity of CY in vitro.23

The cytogenetic profile of fludarabine-treated patients with t-MDS/AML is similar to that of patients treated only with alkylating agents, suggesting a similar mechanism of progenitor cell cytotoxicity. However, in addition to hematopoietic cells, fludarabine also damages non-hematopoietic cells. Eissner et al.24 first reported fludarabine's adverse effects on human microvascular endothelial cells, dermal and alveolar epithelial cell lines, as well as hematopoietic cells. In cell cultures, Berger et al.25 demonstrated a dose-dependent decrease in clonogenic progenitor cells when exposed to fludarabine. Similar toxicity was demonstrated against MSCs. Fludarabine's effects on both hematopoietic progenitor cells and their microenvironment may increase the likelihood of transformation with subsequent cytotoxic insults.

Our small study is retrospective and data were incomplete for some patients, as indicated in Table 1. Furthermore, our patients were selected for auto-HCT and thus may not be representative of all patients with FL. Of special interest would be the population of patients who failed to mobilize enough cells to proceed to transplant, but we did not have data on this population. Our results require validation in a prospectively analyzed patient population.

Given the relatively favorable long-term outcome of patients with FL treated with auto-HCT, caution should be exercised when contemplating administration of multiple cycles of chemotherapy, particularly those containing fludarabine, to patients with FL who may benefit from auto-HCT. Alternative regimens, such as those employing pentostatin or bendamustine, have not been as well studied. Our study suggests that if fludarabine cannot be avoided before auto-HCT in transplant-eligible patients, it should be administered at a cumulative dose <150 mg/m2.


  1. 1

    Armitage JO, Carbone PP, Connors JM, Levine A, Bennett JM, Kroll S . Treatment-related myelodysplasia and acute leukemia in non-Hodgkin's lymphoma patients. J Clin Oncol 2003; 21: 897–906.

  2. 2

    Micallef IN, Lillington DM, Apostolidis J, Amess JA, Neat M, Matthews J et al. Therapy-related myelodysplasia and secondary acute myelogenous leukemia after high-dose therapy with autologous hematopoietic progenitor-cell support for lymphoid malignancies. J Clin Oncol 2000; 18: 947–955.

  3. 3

    Misgeld E, Germing U, Aul C, Gattermann N . Secondary myelodysplastic syndrome after fludarabine therapy of a low-grade non-Hodgkin's lymphoma. Leuk Res 2001; 25: 95–98.

  4. 4

    Morrison VA, Rai KR, Peterson BL, Kolitz JE, Appelbaum FR, Hines JD et al. Therapy-related myeloid leukemia's are observed in patients with chronic lymphocytic leukemia after treatment with fludarabine and chlorambucil: results of an intergroup study, cancer and leukemia group B 9011. J Clin Oncol 2002; 20: 3878–3884.

  5. 5

    Tam CS, Seymour JF, Prince HM, Kenealy M, Wolf M, Januszewicz EH et al. Treatment-related myelodysplasia following fludarabine combination chemotherapy. Haematologica 2006; 91: 1546–1550.

  6. 6

    Zinzani PL, Pulsoni A, Perrotti A, Soverini S, Zaja F, De Renzo A et al. Fludarabine plus mitoxantrone with and without rituximab versus CHOP with and without rituximab as front-line treatment for patients with follicular lymphoma. J Clin Oncol 2004; 22: 2654–2661.

  7. 7

    McLaughlin P, Hagemeister FB, Romaguera JE, Sarris AH, Pate O, Younes A et al. Fludarabine, mitoxantrone, and dexamethasone: an effective new regimen for indolent lymphoma. J Clin Oncol 1996; 14: 1262–1268.

  8. 8

    Friedberg JW, Taylor MD, Cerhan JR, Flowers CR, Dillon H, Farber CM et al. Follicular lymphoma in the United States: first report of the national LymphoCare study. J Clin Oncol 2009; 27: 1202–1208.

  9. 9

    Visani G, Lemoli RM, Tosi P, Martinelli G, Testoni N, Ricci P et al. Fludarabine-containing regimens severely impair peripheral blood stem cells mobilization and collection in acute myeloid leukemia patients. Br J Haematol 1999; 105: 775–779.

  10. 10

    Tournilhac O, Cazin B, Lepretre S, Divine M, Maloum K, Delmer A et al. Impact of frontline fludarabine and cyclophosphamide combined treatment on peripheral blood stem cell mobilization in B-cell chronic lymphocytic leukemia. Blood 2004; 103: 363–365.

  11. 11

    Bolwell B, Kalaycio M, Sobecks R, Andresen S, Mcbee M, Kuczkowski L et al. Autologous hematopoietic cell transplantation for non-Hodgkin's lymphoma: 100 month follow-up. Bone Marrow Transplant 2002; 29: 673–679.

  12. 12

    Maloney DG . Treatment of follicular non-Hodgkin's lymphoma. Curr Hematol Rep 2005; 4: 39–45.

  13. 13

    Kalaycio M, Rybicki L, Pohlman B, Sobecks R, Andresen S, Kuczkowski E et al. Risk factors before autologous stem-cell transplantation for lymphoma predict for secondary myelodysplasia and acute myelogenous leukemia. J Clin Oncol 2006; 24: 3604–3610.

  14. 14

    Harris NL, Jaffe ES, Stein H, Banks PM, Chan JK, Cleary ML et al. A revised European-American classification of lymphoid neoplasms: a proposal from the International Lymphoma Study Group. Blood 1994; 84: 1361–1392.

  15. 15

    Copelan EA, Penza SL, Pohlman B, Avalos BR, Goormastic M, Andresen SW et al. Autotransplantation following busulfan, etoposide and cyclophosphamide in patients with non-Hodgkin's lymphoma. Bone Marrow Transplant 2000; 25: 1243–1248.

  16. 16

    Bolwell BJ, Pohlman B, Andresen S, Kalaycio M, Goormastic M, Wise K et al. Delayed G-CSF after autologous progenitor cell transplantation: a prospective randomized trial. Bone Marrow Transplant 1998; 21: 369–373.

  17. 17

    Bennett JM, Catovsky D, Daniel MT, Flandrin G, Galton DA, Gralnick HR et al. Proposed revised criteria for the classification of acute leukemia. Ann Intern Med 1985; 103: 620–629.

  18. 18

    Saso R, Kulkarni S, Mitchell P, Treleaven J, Swansbury GJ, Mehta J et al. Secondary myelodysplastic syndrome/acute myeloid leukaemia following mitoxantrone-based therapy for breast carcinoma. Br J Cancer 2000; 83: 91–94.

  19. 19

    Morgan SJ, Seymour JF, Grigg A, Matthews JP, Prince HM, Wolf MM et al. Predictive factors for successful stem cell mobilization in patients with indolent lymphoproliferative disorders previously treated with fludarabine. Leukemia 2004; 18: 1034–1038.

  20. 20

    Sacchi S, Marcheselli L, Bari A, Marcheselli R, Pozzi S, Gobbi PG et al. Secondary malignancies after treatment for indolent non-Hodgkin's lymphoma: a 16-year follow-up study. Haematologica 2008; 93: 398–404.

  21. 21

    Laurenti L, Tarnani M, Chiusolo P, La Torre G, Garzia M, Zollino M et al. Low incidence of secondary neoplasia after autotransplantation for lymphoproliferative disease: the role of pre-transplant therapy. Clin Transplant 2008; 22: 191–199.

  22. 22

    Bowcock SJ, Rassam SM, Lim Z, Ward SM, Ryali MM, Mufti GJ . High incidence of therapy-related myelodysplasia and acute leukemia in general hematology clinic patients treated with fludarabine and cyclophosphamide for indolent lymphoproliferative disorders. Br J Haematol 2006; 134: 242–243.

  23. 23

    Yamauchi T, Nowak BJ, Keating MJ, Plunkett W . DNA repair initiated in chronic lymphocytic leukemia lymphocytes by 4-hydroperoxycyclophosphamide is inhibited by fludarabine and clofarabine. Clin Cancer Res 2001; 7: 3580–3589.

  24. 24

    Eissner G, Multhoff G, Gerbitz A, Kirchner S, Bauer S, Haffner S et al. Fludarabine induces apoptosis, activation, and allogenicity in human endothelial and epithelial cells: protective effect of defibrotide. Blood 2002; 100: 334–340.

  25. 25

    Berger MG, Berger J, Richard C, Jeanpierre S, Nicolini FE, Tournilhac O et al. Preferential sensitivity of hematopoietic (HPs) and mesenchymal (MPs) progenitors to fludarabine suggests impaired bone marrow niche and HP mobilization. Leukemia 2008; 22: 2131–2134.

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Correspondence to M Kalaycio.

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Waterman, J., Rybicki, L., Bolwell, B. et al. Fludarabine as a risk factor for poor stem cell harvest, treatment-related MDS and AML in follicular lymphoma patients after autologous hematopoietic cell transplantation. Bone Marrow Transplant 47, 488–493 (2012).

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  • fludarabine
  • follicular lymphoma
  • autologous hematopoietic cell transplantation
  • myelodysplastic syndrome
  • acute myelogenous leukemia

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