Early identification and management of graft failure after ... - Nature

Bone Marrow Transplantation (2008) 42, 35–41 & 2008 Macmillan Publishers Limited All rights reserved 0268-3369/08 $30.00

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ORIGINAL ARTICLE

Early identification and management of graft failure after unrelated cord blood transplantation KW Chan1,2, MS Grimley1,2, C Taylor1,2 and DA Wall1,2 1 Division of Pediatric Stem Cell Transplantation, Texas Transplant Institute, San Antonio, TX, USA and 2Methodist Children’s Hospital, San Antonio, TX, USA

Delayed hematologic recovery is common after unrelated donor umbilical cord blood transplants (UCBT). Clinically it is important to quickly differentiate slow engraftment from graft failure (GF). We report the engraftment data on 110 pediatric UCBT recipients. By day 28, 71 patients achieved an ANC 40.5 109 per liter, and 6 others died early without recovery. Of the remaining 33 patients who were still neutropenic, 20 eventually attained donor myeloid recovery, 3 died of transplant-related complications or recurrent leukemia and 10 survived without donor-derived hematopoiesis. These patients received a second UCBT 33–95 days after the first transplant, after additional immunosuppression. One patient died early, the remaining nine patients were engrafted; eight demonstrated complete, and one mixed, donor chimerism (with subsequent graft loss). Acute GVHD developed in three, and chronic GVHD in six of the eight engrafted patients. Two patients developed EBV-lymphoproliferative disorder. Infections, especially viral, were common and protracted. Six of 10 patients are alive, 165–1375 (median 1147) days after second UCBT. Chimerism studies correlated with subsequent engraftment course. Any result showing o5% donor cells was associated with irreversible graft loss. In conclusion, early second UCBT after primary GF is a feasible treatment option. Chronic GVHD and viral reactivation are common post transplant. Bone Marrow Transplantation (2008) 42, 35–41; doi:10.1038/bmt.2008.40; published online 10 March 2008 Keywords: umbilical cord blood transplant; chimerism; graft failure; second transplants; viral infections

Introduction Delayed engraftment is a frequent problem in umbilical cord blood transplant (UCBT), where an incidence of

Correspondence: Dr KW Chan, Division of Pediatric Blood and Marrow Transplantation, Texas Transplant Institute, 7711 Louis Pasteur Drive, Suite 708, San Antonio, TX 78229, USA. E-mail: [email protected] Received 3 October 2007; revised 16 January 2008; accepted 20 January 2008; published online 10 March 2008

10–30% has been reported.1–5 Since myeloid recovery sometimes occurs as late as 6–8 weeks,1,2,5 it is unclear how to clearly establish a diagnosis of graft failure (GF) as opposed to slow engraftment. Such a determination has critical significance: if there is no possibility of donor engraftment, therapeutic intervention should proceed immediately, since the condition of the patient is precarious due to prolonged marrow aplasia. Conversely, judicious waiting is indicated if the donor cells are engrafting slowly. There is limited information in the literature on how to address this dilemma, and on the fate of these patients. In some series the lack of neutrophil recovery per se has been used as the indication for backup stem cell infusion.1,3 The optimal management of patients with GF has not been established. A number of strategies may be considered in a second attempt to restore hematopoiesis. Rescue with previously cryopreserved autologous hematopoietic stem cells (HSC) is one approach. However pretransplant autologous harvest is not universally feasible (underlying lethal hematologic disorder or lack of hematopoietic reserve) or may carry a high risk of contamination by leukemia or tumor cells. Due to these concerns and the low likelihood of reinfusion, storage of autologous HSC is impractical and not cost effective. Retransplant using a mismatched related donor requires meticulous T-cell depletion. Identification and recruitment of matched unrelated HSC donor is too time-consuming. Additionally, many cord blood (CB) recipients did not have suitable volunteer donors in the first place. Finally performing a second UCBT can be considered. When requested on an urgent basis, CB units can be shipped within 1–2 weeks.6 This advantage allows a rescue transplant to proceed before clinical deterioration. There are several case reports successfully using this approach for the management of GF.7–11 Treatment-related mortality has generally been high after second allogeneic transplants.12–17 Prior cytoreduction and prolonged pancytopenia adversely affect the recipient’s tolerance to further treatment. The design of a preparative regimen must balance the risk of rejection (need for further immunosuppression) and the toxicity to the patients frequently in precarious clinical conditions. Therefore the optimal management strategy for GF after UCBT has not been clearly defined. In this report, we retrospectively review the experience of a single institution, addressing the

Management of graft failure after UCBT KW Chan et al

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clinical course and the management of children with delayed engraftment after UCBT.

at 28 days after UCBT. GF is defined as the absence of donor-derived hematopoiesis. Patients who died before day 28 were considered unevaluable.

Patients and materials

Management of delayed engraftment Patients who lacked neutrophil recovery by day 28 were assessed individually. Myelosuppression from infections or drug toxicity were excluded. The BM was evaluated for cellularity and evidence of neoplastic cells. Patients with complete donor chimerism were observed with appropriate supportive care. Those with mixed chimerism had studies repeated weekly. Patients with no evidence of donor cell engraftment or those who lost their graft were evaluated for retransplantation. Those without active infection or organ dysfunction, and who had performance status X70%, were candidates for second UCBT. Timing for the procedure was based on the underlying diagnoses. Patients with hematologic malignancies and SAA were prepared for retransplant as soon as GF was confirmed, and when a suitable UCB unit was available. Children with nonmalignant diagnoses who had autologous hematologic reconstitution were allowed a longer period of recuperation before proceeding. Selection criteria for CB units were similar to those for the initial transplants. Units with the largest cell dose were of first priority. While DRB1 molecular matching was still preferred as in the first transplant, it was given secondary importance compared to cell dose for the second transplant. Among units with comparable size and matching characteristics the rapidity of shipment availability also affected the choice. The conditioning regimen was designed for intensive immunosuppression, taking into consideration the agents and dose previously employed for the first UCBT.

Patients The medical records of consecutive pediatric patients who underwent UCBT at Methodist Children’s Hospital in San Antonio between March 2001 and December 2006 were reviewed. Recipients of nonmyeloablative conditioning were excluded. Survival and outcome data were collected up to 1 June 2007, with a minimal follow-up of 5 months for all survivors. Histocompatibility testing and selection of umbilical cord blood units HLA Ag were typed by DNA-based methodology: a highresolution technique was used for class II Ag, while low-resolution typing was used for HLA-A and -B loci. Selection of CB units was based primarily on nucleated cell dose, with a target of 5 107 (pre-thaw), but a minimum requirement of 1.5 107 total nucleated cells (TNC)/kg. After that, the choice was based on the best HLA compatibility, with at least three of six loci matching. HLA-DRB1 compatibility between the donor and the recipient was given preference. Conditioning regimens, graft-versus-host disease prophylaxis, and supportive care for first UCBT Transplantation protocols were approved by the institutional review board of the Methodist Children’s Hospital, and written informed consent was obtained from the patients or parents/guardians. The common conditioning protocols were either TBI- or chemotherapy based. The GVHD prophylaxis regimen was a calcineurin inhibitor (CYA or tacrolimus) in combination with methylprednisolone, methotrexate, mycophenolate mofetil and/or sirolimus. Patients were hospitalized in rooms equipped with high-efficiency particulate air filtration system. All patients received hematopoietic growth factor from the day of CB infusion until the ANC exceeded 2 109 per liter. Monitoring for engraftment after umbilical cord blood transplant Blood counts were performed daily during initial hospitalization. Myeloid recovery was defined as the first of 3 consecutive days when the ANC was X0.5 109 per liter. Chimerism analysis was performed by DNA amplification of informative polymorphic short tandem repeats. The values had an accuracy of ±5%. Chimerism studies from peripheral blood (unfractionated) were usually begun around the third week after transplant, and repeated as indicated, according to the patients’ condition. In general, patients who were persistently neutropenic or those with mixed chimerism were tested every 1–2 weeks. Full chimerism is defined as complete replacement of host by donor lymphohematopoiesis, while mixed chimerism is the detection of 5–95% cells of donor origin. Delayed engraftment is defined as an ANC to o0.5 109 per liter Bone Marrow Transplantation

Results Patients A total of 118 consecutive UCBT were performed between March 2001 and December 2006 at the Methodist Children’s Hospital. Eight patients were excluded because they received a nonmyeloablative conditioning regimen. The clinical characteristics of the 110 patients reviewed are shown in Table 1. Outcome of initial UCBT Of 110 patients, 91 patients achieved myeloid recovery from donor cells at a median of 18 (range 10–65) days after UCBT. However only 71 of these patients achieved donorderived ANC 40.5 109 per liter by day 28. Six patients died between 8 and 28 days after transplant from multiorgan failure and/or active infections, and were unevaluable. Of the 33 who remained neutropenic, 20 eventually went on to myeloid recovery. Three patients had autologous reconstitution after day 28. Ten patients had no evidence of any myeloid recovery: three died (due to aspergillus pneumonia, severe GVHD and leukemic relapse). Ten patients received the second UCBT, including all three who had autologous recovery (Figure 1).


37 Table 1

Patient characteristics

Age (years) Weight (kg) Gender (M:F) Diagnosis Malignancies ALL AML CML/MDS/JMML

71 Engrafted by day 28

84 44 26 8/3/3

Nonmalignancy SAA/Fanconi Anemia SCID/WAS HLH Othersa

26 6/1 7/3 5 4

HLA match X5/6 p4/6

54 56

TNC (107/kg)b CD34+ (105/kg)b

110 1st UCBT

0.1–18.4 (median 5.3) 4–85 (median 22) 71:39

Deaths before day 28 no WBC recovery

20 3 91 Myeloid engraftment

Engrafted after day 28

10

Autologous recovery

No WBC recovery 2

2.1–15.5 (median 7.5) 1.7–20.4 (median 6.0)

6

33 Alive, ANC 95% donor cells

10 Mix chimera*

CD34+(105/kg)

4 1

4 5 2nd UCBT 10 Death 1

Lost donor cells

HLA match (based on least matched for double units) X5/6 p4/6 TNC (107/kg)

15

Death, no ANC ANC recovery recovery

4 (3/1) 6 (2/2/1/1)

8 2

3 7 2.4–15.2 (median 7.8) 2.0–17.7 (median 6.3)

Abbreviations: CD40L-def ¼ CD 40 ligand deficiency; HLH ¼ hemophagocytic lymphohistiocytosis; MDS ¼ myelodysplastic syndrome; SAA ¼ severe aplastic anemia; TNC ¼ total nucleated cells; UCBT ¼ umbilical cord blood transplants. Kostmann’s indicates Kostmann’s syndrome.

Death, no ANC Complete recovery donor chimerism

Figure 2

Chimerism results of 36 patients with delayed myeloid engraftment by day 28 (3 patients died early and did not have chimerism study done). *Mixed chimerism ¼ 5–95% donor cells.

surviving patients revealed complete donor engraftment in eight cases. The patient with Kostmann’s syndrome demonstrated mixed chimerism, with eventual loss of his second graft. He is now engrafted with a third CB transplant.

Graft-versus-host disease after second Umbilical cord blood transplant Acute GVHD was diagnosed in three of the nine evaluable patients. It involved the skin, with or without gut involvement (overall grade II–III). All responded to therapy. Six of the eight engrafted patients went on to develop chronic GVHD, five with extensive and one with limited involvement. At the time of report, three patients remained on systemic immunosuppressive therapy for the control of chronic GVHD. Complications after second UCBT None of the children developed hepatic veno-occlusive disease or multiorgan failure. Four patients had bacteremia during the neutropenic phase, all recovered. Two patients developed idiopathic pneumonitis syndrome (cultures from broncho-alveolar lavage (BAL) negative), which had full recovery after steroid and etanercept therapy. Bone Marrow Transplantation

0.5–16.1 (median 6.5) 6.1–64.4 (median 20.4) 7:3

Table 3

Conditioning regimens for second UCBT

Primary (n ¼ 7) CY 50 mg/kg (day 6); Flu 35 mg/m2 (day –6 to –2); TBI 2 Gy (day 1); ±ATG 30 mg/kg (day 4 to –2) Aplastic Anemia (n ¼ 2) TBI 6 Gy + CY 120 mg/kg + ECP (n ¼ 1) TBI 6 Gy + CY 120 mg/kg + Alentuzumab 1 mg/kg (n ¼ 1) Other (n ¼ 1) Alentuzumab (1 mg/kg) + Flu 90 mg/m2 Abbreviations: ECP ¼ extracorporeal photopheresis; Flu ¼ fludarabine; UCBT ¼ umbilical cord blood transplants.

Late infections were a major problem and were mostly viral in etiology. After engraftment, multiple infections were encountered in seven of the nine surviving patients. These included viremia from CMV (n ¼ 2), BKV (n ¼ 2), HHV-6 (n ¼ 1), EBV (n ¼ 1) and adenovirus (n ¼ 1). The infections were protracted, with persistent or rising viral loads that lasted for months in four of the six infection episodes. Two patients also developed acyclovir-resistant herpes stomatitis. In addition, two children had pseudomonas sepsis, one had nocardia isolated from a BAL, and another patient had candidal meningitis. EBV-associated lymphoproliferative disorder developed in two patients on days 82 and 127 after transplant. Both had concurrent EBV DNA detected in the blood. Treatment included reduction of immunosuppression and rituximab. One patient with monomorphic histology died despite of treatment, and the other had a complete response.


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Survival and performance status after second UCBT As of 1 June 2007, 6 of 10 recipients were alive, at a median follow-up of 1147 days (range 165–1375 days). The median Lansky performance status of the survivors is 90%, ranging from 60 to 100%. Among the five patients with chronic GVHD who are alive, three remain on immunosuppressive treatment. Four patients had died: one at the immediate post-transplant period, and three at days 118, 307, 319 from infection-related complications that included EBVlymphoproliferative disorder, pseudomonas sepsis and interstitial pneumonitis, respectively.

Discussion In this single institution review, 91 (83.6 %) of 110 pediatric patients undergoing UCBT achieved myeloid recovery. However, only 71 of the 91 patients attained an ANC 40.5 109 per liter by day 28 of the procedure. This result is consistent with the incidence of delay in or lack of engraftment reported by other UCBT series.1–5 The 33 neutropenic patients who survived to this point had a diverse clinical outcome: 20 eventually had myeloid recovery, and two others died of GVHD and recurrent leukemia, respectively, without recovery. Eleven patients (10%) fulfilled the criteria of GF, as evidenced by absence or rapidly falling donor cell chimerism. The incidence is high enough to warrant the establishment of a rescue strategy prior to the start of any UCBT. Our experience showed that a second UCBT for rescue is feasible in 10 of the 11 patients with primary GF. These transplants could be performed within the time frame of a haploidentical, T-cell depleted, related donor transplant and much sooner than obtaining HSC from an unrelated voluntary adult donor.12–15 Second allogeneic HSCT has been associated with an early mortality rate that exceeded 50%, and poor long-term survival.12,13,15 Conditioning with cytotoxic agents resulted in a high incidence of toxicity, but not superior engraftment rate or survival.11–13,15 Narimatsu et al.10 reported primary GF in nine adult UCBT recipients. Four underwent second UCBT after fludarabine, TBI (2–4 Gy) and melphalan or busulfan conditioning. All developed grade 3–5 regimenrelated toxicity, and only one patient was alive at 9 months. In our patients a predominantly immunosuppressive regimen was well tolerated, even for those retransplanted within 2 months of the initial procedure. This regimen has also been used in adults undergoing initial double UCBT.18 Neutrophil recovery was rapid and was associated with complete donor chimerism. However we were not sure that this approach could be extrapolated to patients initially treated with reduced-intensity conditioning. For example, both of our patients with severe aplastic anemia had already received a predominantly immunosuppressive preparation. After GF, we chose a more intensive conditioning regimen with successful donor-cell engraftment. Recent reports do indicate that another reducedintensity regimen can lead to successful engraftment.7–9 Infectious complications accounted for most of the early deaths after second transplants.12,13,15,17 Our patients did not encounter a high incidence of early infections, which

might be the result of prompt second UCBT. Despite myeloid recovery, they suffered from a number of late, mostly viral infections that were frequently protracted and difficult to eradicate. In several cases the viral load persisted and even increased over months, reflecting an ongoing defective immune system. This high frequency of opportunistic infections may be the result of several predisposing factors. First, recipients of UCBT are at increased risk of viral infections due to lack of adoptive transfer of donor immunity.19–21 The additional course of immunosuppression prior to second UCBT might have further promoted viral reactivation in our patients. Finally most patients required treatment for chronic GVHD, which could have also contributed to the risk of infection. Routine monitoring for the more common post transplant viruses is prudent in the setting of second UCBT. Two of our patients developed EBV-LPD. In general, the incidence of EBV-LPD after UCBT is low (2%), but patients on immunosuppressive treatment for GVHD were found to be at a higher risk.22 Furthermore Brunstein et al.23 observed a much increased frequency (21%) in the cases of a nonmyeloablative conditioning that included ATG. All our patients received further immunosuppressive preparation prior to the second UCBT, and seven of nine had two courses of ATG within a 3-month period. In this high risk population, serial monitoring of Epstein-Barr viral load and preemptive rituximab therapy has been recommended.22,23 A higher incidence of GVHD has been reported in second transplants,12,14,15 but the incidence was reduced by intensive prophylaxis.7,14 Acute GVHD is relatively uncommon in our series, with our approach of full dose prophylaxis. However, extensive chronic GVHD, which is usually rare after UCBT, occurred in six of eight evaluable patients; necessitating prolonged immunosuppressive therapy.1,4,5,24 There are conflicting reports as to whether the incidence of chronic GVHD in second allogeneic transplants is increased among recipients of other HSC sources, but long-term survivors were few in most series.12–14,16 Extensive chronic GVHD has also been encountered in other second UCBT recipients.7,8 The reason for the high incidence of this complication remains unclear. We recommend careful monitoring of and early intervention of chronic GVHD in children undergoing second transplants. Early identification of GF allows prompt intervention, which is the key for the successful management. However, early differentiation of delayed engraftment from GF following UCBT is difficult. PCR amplification of polymorphic genetic loci (microsatellites) is an established methodology to quantitatively assess chimerism post transplant. The accuracy of the study is between 97–99%, and the sensitivity of detecting donor or recipient DNA can be as low as 1%.25 The turnaround time is 3–5 days and the testing can be performed with very low blood counts. Limited data existed in chimerism analysis post UCBT, and this series represented the largest reported so far. We found that if complete donor chimerism was detected at the third or fourth week after UCBT, graft loss did not occur. This is particularly pertinent to the leukemia patients, who, due to pretransplant chemotherapy-induced immunosuppression Bone Marrow Transplantation


40

and intensive transplant preparative regimens, normally have complete donor chimerism at time of initial myeloid recovery. Our observation is in keeping with those made in these patients who received other unmanipulated HSC grafts.26–28 Mixed chimerism was found in two of our leukemia patients and both went on to GF. Monitoring chimerism at short time intervals helped to identify the course of these patients. Cimino et al.28 showed that mixed chimerism in UCBT recipients before day 35 predicted GF, with or without autologous reconstitution; and a high probability of leukemia relapse. Patients with nonmalignant disorders26,29 and those who have not received recent chemotherapy18 are more likely to develop mixed chimerism after HSCT. A third of our patients with these conditions showed such findings, but many became stable mixed, or complete chimerism over time. However a significant fall in percentage of donor cells on subsequent chimerism analysis heralded graft loss. In all diagnoses, a single detection of o5% donor cells at any time point was associated with irreversible GF. Such a result should prompt implementation of rescue procedures. A workshop sponsored by the National Marrow Donor Program (NMDP) and the International Blood and Marrow Transplant Research (IBMTR) considered routine chimerism analysis after myeloablative HSCT for hematologic malignancies not essential, unless intervention with DLI was a consideration.26 In UCBT, we found that performing these studies as confirmation after myeloid recovery provided little additional clinical information. However, in the setting of delayed neutrophil recovery, chimerism studies as early as 3–4 weeks after UCBT helped in (1) identifying cases of GF for prompt therapeutic intervention, (2) reassurance in cases of complete donor chimerism and (3) determining the need for frequent chimerism analysis in mixed chimera. Two recent reports also utilized early chimerism results to decide on early second UCBT.8,9 Our experience demonstrates that second unrelated donor UCBT is a viable option in the management of primary GF following UCBT, and it should be considered early. With experience we have been able to perform the rescue procedure earlier (first five cases: median 84 days, last four cases: median 55 days). We also have demonstrated that PCR-based chimerism studies can provide useful information in patients with delayed engraftment that may affect treatment decision. Absence or rapid decrease of donor cell should prompt intervention.

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