Allogeneic blood stem cell and bone marrow transplantation for acute myelogenous leukemia and myelodysplasia: influence of stem cell source on outcome

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1 Bone Marrow Transplantation, (1999), Stockton Press All rights reserved /99 $15. Allogeneic blood stem cell and bone marrow transplantation for acute myelogenous leukemia and myelodysplasia: influence of stem cell source on outcome JA Russell 1,2,3,4, L Larratt 4, C Brown 1,3, AR Turner 4, A Chaudhry 1, K Booth 2, RC Woodman 1, J Wolff 2, K Valentine 1, D Stewart 1,3, JD Ruether 1,3, BA Ruether 1, J Klassen 1, AR Jones 1, E Gyonyor 1,3, M Egeler 2, J Dunsmore 2, S Desai 4, MJ Coppes 2, T Bowen 2, R Anderson 2 and M-C Poon 1 Alberta Bone Marrow Transplant Program and Departments of Medicine and Oncology, 1 Foothills Hospital; 2 Alberta Children s Hospital; and 3 Tom Baker Cancer Centre, Calgary; and 4 Cross Cancer Institute, Edmonton, Alberta, Canada Summary: We have compared the outcomes of 87 patients with acute myelogenous leukemia (AML) and myelodysplasia (MDS) receiving matched sibling transplants with stem cells from peripheral blood (blood cell transplant, BCT) or bone marrow (BMT). In good risk patients (AML in CR1) granulocytes recovered to /l a median of 14 days after BCT compared with 19 days after BMT (P.1). For patients with poor risk disease (AML beyond CR1 and MDS) corresponding figures were 16 vs 26 days (P.1). Platelet recovery to /l was also faster after BCT (good risk 12 vs 2 days, P.1; poor risk 17 vs 22 days, P.4). Red cell transfusions were unaffected by cell source, but BCT recipients required less platelet transfusions (good risk 1 vs 5, P.2; poor risk 5 vs 11, P.4). Blood cell transplants resulted in more chronic GVHD (86% vs 48%, P.5) and a significantly higher proportion of recipients with KPS of 8% or less (48% vs 5%, P.4). Disease-free survival at 4 years was 23% for both groups of poor risk patients but outcome in good risk patients was better after BCT (93% vs 62%, P.47) related mainly to less relapse. While disease-free survival may be better after BCT than BMT for AML in CR1, quality of life may be relatively impaired. Keywords: acute myelogenous leukemia; blood cell transplant There has been a recent increase in the use of cells mobilized into the blood of donors by growth factors and collected by leukapheresis as an alternative to a conventional bone marrow harvest Such peripheral blood stem cell (PBSC) or blood cell transplants (BCT) may provide a more tolerable option for the donor. 1 A number of studies, some with retrospective control patients, have indicated that there may also be early advantages for the BCT recipient, Correspondence: Dr JA Russell, Department of Medicine, Tom Baker Cancer Centre, th St NW, Calgary, Alberta, Canada T2N 4N2 Received 27 September 1998; accepted 2 July 1999 in particular faster engraftment and immune reconstitution, fewer transfusions and shorter hospital stay Although more T cells are given with BCT than BMT, increased rates of acute graft-versus-host disease (GVHD) have not been observed although chronic GVHD appears more frequent. 8,17 2 Some of these questions will be addressed more definitively by ongoing multicenter prospective randomized studies in Canada, Europe and the US. 11,21 Pending these results there is a need for guidance concerning the circumstances, if any, where BCT might be chosen outside clinical studies. To this end, we report a series of patients with acute myelogenous leukemia (AML) and myelodysplasia (MDS) undergoing BCT or BMT in a single program. Patients and methods Patients Eighty-seven consecutive patients with AML and/or MDS received a first transplant between April 1987 and February For the purpose of analysis they were divided into four groups according to remission status and stem cell source (Table 1). Five patients in CR2 were assigned to the poor risk groups. Two of these, receiving BCT, had other poor risk features, namely cytogenetic relapse and treated CNS disease. In order to assess comparability between groups receiving BCT or BMT other parameters known to affect outcome after BMT were documented including age, number of chemotherapy courses to obtain CR1 (in CR and relapsed patients), and cytogenetics. 22 In this respect patients with t(15;17) and inv 16 were considered good risk, those with abnormalities of chromosomes 5 and 7 and/or complex karyotypes, poor risk. All others were assigned to the intermediate risk group. Because we started BCT in 1993 follow-up is shorter in these patients, particularly the good risk subgroup. We were initially uneasy about using BCT in the latter patients in view of the low transplant-related mortality for early leukemia after BMT. 23

2 BCT vs BMT for AML and MDS 1178 Table 1 Patient characteristics BCT good risk BMT good risk BCT high risk BMT high risk Number Median age (range) (15 5) (11 5) (3 56) (9 53) No. (%) 18 years 2 (13) 2 (1) 1 (4) 3 (12) Diagnosis De novo AML 15 (1) 21 (1) 16 (62) 2 (8) Secondary AML 1 (4) (after ABMT) AML evolved from MDS 3 (12) 1 (4) MDS 2 (raeb-t, 1 raeb, 2 (8) 1 raeb monosomy 7) (1 raeb-t 1 ra monosomy 7) Other 1 (MDS with 1 (4) (acute fibrosis) myelofibrosis) Stage/response to chemotherapy CR1 17 (1) 21 (1) CR2 3 (12) 2 (8) 1st relapse 9 (35) 12 (48) Induction failure 4 (15) 6 () Not treated 1 (32) 5 (2) No. (%) achieving CR1 after 1 course of chemotherapy 12 (8) 19 (9) 9/12 () 13/14 (93) Cytogenetic risk group No./No. evaluable Good 2/5 3/23 2/17 Intermediate 5/5 2/5 12/23 1/17 Poor 1/5 8/23 5/17 Conditioning BuCy2 (busulfan 16 mg/kg cyclophosphamide (Cy) 12 mg/kg) 4 (27)* 19 (86)* 14 (54)*** 21 (86)*** VP/TBI (VP16 6 mg/kg TBI 12 cgy) 11 (73)** 2 (9)** 7 (27) 3 (12) VP16 6 mg/kg TBI 5 cgy 1 (3) Cy 12 mg/kg TBI 5 cgy 3 (12) 1 (4) ra refractory anemia; raeb refractory anemia with excess blasts; raeb-t refractory anemia with excess blasts in transformation. *P.6; **P.2; ***P.9. Donors Donors were genotypically HLA-A, -B and -DR identical siblings. Marrow donors underwent conventional harvests with target nucleated cell yields of per kg recipient body weight. Blood cell donors were treated with rh- G-CSF (Amgen, Thousand Oaks, CA, USA) (6 18 g/kg) SC daily for 2 4 days. Leukapheresis was carried out using a Cobe Spectra Cell Separator (Cobe Laboratories, Lakewood, CO, USA) until target yields of CD34 cells exceeded CD34 cells/kg. Bone marrow cells were given fresh in all but two cases. Blood cells were cryopreserved in a controlled-rate freezer using 1% DMSO as a cryoprotectant and stored in liquid nitrogen. Treatment of recipients There was a move towards use of the VP/TBI conditioning protocol with time in order to avoid the hemorrhagic cystitis often seen after BuCy2. Thus, more BCT patients received VP/TBI. All but two patients (receiving BMT) were nursed without protective isolation. All blood products were from CMV seronegative donors. Single donor platelets were given to maintain counts /l and red cells to keep hemoglobin levels 8 g/l. Growth factors were not given routinely. Antibacterial and antipneumocystis prophylaxis comprised ciprofloxacin and/or trimethoprim/sulfamethoxazole. Prophylactic ganciclovir was given to four CMV seronegative recipients of SCT (three BCT, one BMT) from seropositive donors, no systemic antifungal prophylaxis was used. The acute GVHD prophylaxis protocol comprised cyclosporin A orally or intravenously twice daily to maintain blood levels between and 4 mol/l. Methotrexate was given in doses of 15 mg/m 2 on day 1 and 1 mg/m 2 on days 3, 6 and 11. Folinic acid 5 mg was started h after each dose of methotrexate and continued every 6 h until 12 h before the next dose. 26 Engraftment Daily blood counts were done until discharge with bone marrow aspirations at 3 months for surviving patients or as clinically indicated. Granulocyte engraftment was defined as a count of /l. For the purpose of analysis, patients receiving G-CSF after SCT were excluded. The platelet count needed to be above /l without transfusion for 3 days. Kaplan Meier plots of engraftment censored patients at time of death. Plots continued to day 42. Delay beyond day 42 was considered graft failure. The source of engrafted cells in peripheral blood and/or

3 BCT vs BMT for AML and MDS bone marrow was confirmed by comparison of donor and recipient polymerase chain reaction (PCR) amplified and radiolabeled DNA fragments resolved on polyacrylamide gels and detected by autoradiography. a Graft-versus-host disease Graft-versus-host disease (GVHD) was graded according to standard criteria. 27 Only cases of clinical and/or histological acute GVHD occurring before day 1 were classified as acute GVHD. Patients were considered evaluable for chronic GVHD beyond day 6. Informed consent and choice of procedure Donors, recipients and parents, where appropriate, were fully informed about the investigational nature of BCT. The protocol and consent forms for BCT were approved by the University of Calgary Conjoint Medical Ethics Committee. The protocol was modified in December 1994 to include AML in CR1 as an eligibility criterion. One donor elected to give bone marrow. Bone marrow was also given to one patient on a multicenter protocol which did not permit the option of BCT. The remaining donors chose BCT. % engrafted Days b % engrafted 1 5 Statistical analysis The distributions of time to events were compared using the logrank test. The Mantel Whitney rank sum test was employed for comparison of transfusion requirements and Fisher s exact test for distribution of risk factors between groups. P values are reported only if.1 or less, those below.5 are considered significant. Analysis was performed on a Macintosh computer using GraphPad Prism software (GraphPad Corp., San Diego, CA, USA) BCT GR BMT GR BCT PR BMT PR 21 Days Figure 1 Kaplan Meier plot of probability of recovery of (a) neutrophils to /l and (b) platelets to /l. Other details are in Table 2a and b. GR good risk, PR poor risk Results Engraftment Three poor risk patients (two BCT, one BMT) received G- CSF post transplant, two of them only a single dose. Two poor risk patients died without granulocyte engraftment on days 17 and 18 after BMT. A third, with progressive disease, did not engraft until day 16. Acceleration of engraftment after BCT compared with BMT was highly significant in both groups (Figure la and Table 2a). In BMT patients recovery was faster in the good risk group only. Platelets engrafted in all but two poor risk BCT patients who died at days 35 and 41 of leukemia and GVHD, respectively. A third patient did not have self-sustaining counts until day 19 but significant megakaryopoiesis was seen in the marrow on day 41. In addition to the two poor risk BMT patients dying before granulocyte recovery, platelet counts were not sustained in four others. One received a second BMT for progressive disease, one died of organ failure on day 47, one of hemolytic-uremic syndrome on day 79 and the fourth of GVHD on day 182. Platelet engraftment was significantly faster after BCT than BMT Table 2a Median (range) days to granulocyte engraftment Good risk (11 2) (15 34) Poor risk (11 27) (17 16) P.89.3 Table 2b Median (range) days to platelet engraftment Good risk (5 21) (11 4) Poor risk (1 19) (14 29) P.1.1

4 118 BCT vs BMT for AML and MDS in both risk groups and also in good compared with poor risk patients (Figure lb and Table 2b). Donor origin of marrow and/or peripheral blood cells was confirmed in all SCT recipients who survived 1 days without relapse. Transfusion Stem cell source had little influence on red cell transfusions but significantly more products were used by poor risk patients (Table 3a). Both cell source and risk category had a highly significant influence on platelet transfusions (Table 3b). GVHD There was no significant difference in the incidence of acute GVHD grades II IV or grades III IV in the four subgroups (Table 4). Of the 11 deaths not due to relapse in the poor risk BCT group six occurred before day 1, of which four were primarily due to acute GVHD (Table 5). In contrast, none of the four early deaths after BMT were due to GVHD (P.8). Chronic GVHD (clinically extensive in all affected patients) occurred equally in good and poor risk patients but in this case there was a significant overall influence of stem cell source (Figure 2b). The incidence of chronic GVHD at 2 years was 86% in the BCT group compared with 48% in BMT recipients (P.5). This difference reached significance for good risk (86% for BCT vs 42% for BMT, P.1) but not poor risk patients (85% for BCT vs 54% for BMT, P NS). Twelve of 21 surviving BCT recipients remain on treatment for chronic GVHD months post transplant. All a % acute GVHD Days 35% grade II IV 18% 15% grade III IV 5% 1 Table 3a Median (range) red cell transfusions Good risk 2 2 NS ( 8) ( 1) Poor risk ( 64) ( 63) P.2.2 NS not significant. b % chronic GVHD % 85% 42% 54% Table 3b Median (range) platelet transfusions Good risk (1 4) ( 59) Poor risk (1 85) (3 126) P BCT GR BMT GR BCT PR BMT PR Figure 2 Kaplan Meier plot of probability of (a) acute GVHD (solid lines represent BCT patients) and (b) chronic GVHD. Other details are in Table Table 4 Incidence of acute and chronic GVHD BCT good risk BMT good risk BCT poor risk BMT poor risk Acute GVHD % grades II IV 4* 14* % grades III IV No. at risk for chronic GVHD at 2 months % chronic GVHD 86** 42** *P.7; **P.1.

5 BCT vs BMT for AML and MDS Table 5 Cause of non-relapse death in poor risk patients 1 93% 1181 Death before day 1 Death after day 1 BCT acute GVHD (4) cardiac failure (n 26) hemorrhage/cmv enteritis cerebral infarction pneumonia chronic GVHD (2) pulmonary fibrosis BMT multiple organ dysfunction (3) infection (n ) hemolytic-uremic syndrome pneumonia chronic GVHD (1 bronchiolitis) (2) % Disease-free 5 23% 62% 23% a % relapse/persistent disease 5 63% 54% 35% 7% BCT GR Figure 4 BCT PR BMT GR BMT PR Kaplan Meier plot of probability of disease-free survival. in poor risk patients were 54% after BCT and 63% after BMT (P NS). Non-relapse mortality No good risk patient died within 1 days but one BMT recipient died of pneumonia at 6 months, for an overall rate in this group of 5% (Figure 3b). In the poor risk patients there was no significant difference in non-relapse mortality at 1 days (BCT % vs BMT 18%) or 2 years (BCT 5% vs BMT 45%). b 1 Survival and quality of life % dead 5 5% 45% % 5% There was a trend to greater disease-free survival at 4 years after BCT in the good risk patients (93% vs 62%, P.47, Figure 4). In poor risk patients relapse-free survival is 23% in both groups. With a median follow-up of survivors of 34 months (range months) two of 21 surviving BCT recipients have Karnofsky status (KPS) limited to 6% by bronchiolitis in one and 7% from a peripheral neuropathy in a second. Ten BCT patients (48%) are functioning, at KPS 8% or less, compared with one of 2 BMT patients (5%) (P.4) Discussion BCT GR BMT GR BCT PR BMT PR Figure 3 Kaplan Meier plot of probability of (a) relapse and (b) nonrelapse mortality. 2 surviving BMT patients are off treatment beyond 5 years. Relapse Of the good risk patients a single BCT recipient relapsed (7%) compared with seven BMT patients (37%) (P.7, Figure 3a). Rates of relapse and persistent disease at 2 years Most previous comparisons of BCT with BMT have been retrospective and have involved rather heterogeneous patient populations with respect to diagnosis, treatment protocols and other risk factors While this report focuses on acute myelogenous leukemia and myelodysplasia, these diagnoses still encompass a spectrum of disease rather than a homogeneous entity. Our patients are grouped according to the most powerful risk factor, remission status, and the BCT and BMT groups appear to be fairly well matched for other disease-related factors believed to affect outcome. 22 Although the BMT patients were treated over an 11-year period, our support protocols, particularly GVHD prophylaxis, have changed little over this time. Prophylactic flu-

6 1182 BCT vs BMT for AML and MDS conazole and ganciclovir may have improved outcomes in some centers but we do not use fluconazole routinely and ganciclovir only in a small minority of recently treated patients. The only death related to CMV was in a BCT recipient. The major difference in transplant protocol was the use of BuCy rather than VP/TBI in most BMT patients. It may be reasonable to assume that the conditioning regimen is less likely to influence speed of engraftment than other outcomes. However, a large study from the Southwest Oncology Group indicated that VP/TBI was equivalent to BuCy, at least in advanced leukemia. 28 A recent metaanalysis of studies comparing BuCy with TBI-containing regimens indicates no difference in disease-free survival although it allowed the possibility that the latter could be superior. 29 Any influence of conditioning in our CR1 patients would be due to the antileukemic effect. This would be consistent with a French randomized trial comparing BuCy with CyTBI in AML whereas a second study in early CML showed the opposite effect. 3,31 Our data are consistent with those of others in demonstrating acceleration of both neutrophil and platelet engraftment after BCT. The effect on granulocyte recovery seems greater than in some other reports when methotrexate was used, conceivably because we added folinic acid to this regimen. 26 The reduction in transfusion requirements is significant only for platelets. Lack of platelet recovery in both groups was largely related to such factors as GVHD, persistent leukemia and consumption. The significant influence of risk group on engraftment and transfusion requirements emphasizes the importance of this variable when comparing the effect of cell sources. We previously showed that time to first discharge is shorter after BCT. 6 However, these benefits in the early post-transplant course are not accompanied by a significant impact on early non-relapse mortality. The widely held impression from a number of previous reports has been that stem cell source has little influence on acute GVHD despite the higher T cell content in leukapheresis products. 2 9,11 A number of explanations have been offered for this somewhat unexpected finding, including immune modulation by G-CSF given to the donor and the increased monocyte numbers in blood cell grafts Although this study also shows no significant difference in the incidence of acute GVHD we are concerned by the hint that acute GVHD may contribute more to early mortality in the poor risk BCT patients. The increased rates of chronic GVHD after BCT have been suspected for some time and are consistent with the observations in patients with aplastic anemia receiving buffy coat infusions. 8,16 19,37 The shorter follow-up of BCT patients may explain some of the differences in current KPS scores. However, even this relatively simple estimate of functional capacity indicates the possibility of impaired quality of life in a significant proportion of BCT survivors. A critical question remains until the results of prospective randomized studies are available. That is whether or not this study indicates any circumstances in which one stem cell source should be preferred. Our concern that BCT could make matters worse for patients in CR1 seems to have been unjustified if only disease-free survival is considered. In this group the only way to increase relapse-free survival substantially would be by an influence on relapse. Theoretically, one might expect an enhanced graft-versusleukemia effect to operate more effectively in those patients with minimal leukemia at the time of SCT. 38 If there is indeed a trend to less relapse it would need to be consistent enough to compensate for the morbidity of chronic GVHD. We have never used BCT to treat patients with CML in chronic phase because of the possibility of more chronic GVHD, which is virtually the only cause of death in our patients. 23 Results of this study provide justification for this approach. Finally, although there may be an early economic advantage for BCT our results indicate that this could be offset by the expense of treating later complications. Acknowledgements Our thanks are due to the nursing staff of the Tom Baker Cancer Centre, Foothills Hospital and Alberta Children s Hospital for their help in caring for these patients. References 1 Anderlini P, Przepiorka D, Körbling M et al. 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