A prospective randomized toxicity study to compare reduced-intensity and myeloablative conditioning in patients with myeloid leukaemia undergoing allogeneic haematopoietic stem cell transplantation.

BACKGROUND: To our knowledge, no randomized toxicity studies have been conducted to compare myeloablative conditioning (MAC) and reduced-intensity conditioning (RIC) in allogeneic haematopoietic stem cell transplantation (HSCT). METHODS: Adult patients ≤60 years of age with myeloid leukaemia were randomly assigned (1 : 1) to treatment with RIC (n = 18) or MAC (n = 19) in this Phase II single-centre toxicity study. RESULTS: There was a maximum median mucositis grade of 1 in the RIC group compared with 4 in the MAC group (P < 0.001). Haemorrhagic cystitis occurred in eight of the patients in the MAC group and none in the RIC group (P < 0.01). Results of renal and hepatic tests did not differ significantly between the two groups. RIC-treated patients had faster platelet engraftment (P < 0.01) and required fewer erythrocyte and platelet transfusions (P < 0.001) and less total parenteral nutrition (TPN) than those treated with MAC (P < 0.01). Cytomegalovirus (CMV) infection was more common in the MAC group (14/19) than in the RIC group (6/18) (P = 0.02). Donor chimerism was similar in the two groups with regard to CD19 and CD33, but was delayed for CD3 in the RIC group. Five-year transplant-related mortality (TRM) was approximately 11% in both groups, and rates of relapse and survival were not significantly different. Patients in the MAC group with intermediate cytogenetic acute myeloid leukaemia had a 3-year survival of 73%, compared with 90% among those in the RIC group. CONCLUSION: Reduced-intensity conditioning had several advantages compared with MAC, including less mucositis, less haemorrhagic cystitis, faster platelet engraftment, the need for fewer transfusions and less TPN, and fewer CMV infections. Both regimens were tolerated and TRM was low.

OuaSelect, a novel ouabain-resistant human marker gene that allows efficient cell selection within 48 h.

Efficient selection of gene-modified cells is required for a number of potential gene therapy applications, as well as molecular biology studies. Ideally, a clinical selection regimen would combine high selection speed, efficiency and efficacy, in addition to clinical grade selection techniques and low immunogenicity. To our knowledge, a selection marker satisfying all these features is so far not available. Ouabain is a clinically used cardiac glycoside and selective Na(+)/K(+)-ATPase inhibitor. On the basis of the high sensitivity of human Na(+)/K(+)-ATPase proteins to ouabain, and rapid killing of cells upon exposure, we have screened the ubiquitously expressed Na(+)/K(+)-ATPase alpha1 subunit for mutations that could greatly increase its resistance to ouabain. Two amino-acid substitutions, Q118R and N129D were sufficient to confer a two log greater resistance to ouabain in HeLa, Jurkat, U2OS cells and in primary cells. Furthermore, following transduction of primary lymphocytes with the alpha1(Q118R/N129D) gene, >99% pure populations of gene-modified cells were achieved with a recovery rate of >80% after 48 h of exposure to ouabain. These results identify the human alpha1(Q118R/N129D) (OuaSelect) as a promising selection marker gene for safe, rapid and cost-effective selection in clinical gene therapy and molecular biology research.

Risk factors for fatal infectious complications developing late after allogeneic stem cell transplantation.

Infectious complications remain a major problem contributing to significant mortality after hematopoietic allogeneic stem cell transplantation (HSCT). Few studies have previously analyzed mortality due to late infections. Forty-four patients dying from an infectious complication were identified from a cohort of 688 consecutive patients surviving more than 6 months without relapse. A control group of 162 patients was selected using the year of HSCT as the matching criterion. Out of 44 patients, 30 (68%) died from pneumonia, 7/44 (16%) from sepsis, 5/44 (11%) from central nervous system infection and 2/44 (4.5%) from disseminated varicella. The cumulative incidences of different types of infection were 1.6% for viral, 1.5% for bacterial and 1.3% for fungal infections and 0.15% for Pneumocystis jirovecii pneumonia. The majority (66%) of the lethal infections occurred within 18 months after HSCT. Acute GVHD (relative risk (RR): 7.19, P<0.0001), chronic GVHD (RR: 6.49, P<0.001), CMV infection (RR: 4.69, P=0.001), mismatched or unrelated donor (RR: 3.86, P=0.004) and TBI (RR: 2.65, P=0.047) were independent risk factors of dying from a late infection. In conclusion, infections occurring later than 6 months after HSCT are important contributors to late non-relapse mortality after HSCT. CMV infection or acute GVHD markedly increase the risk.

Evaluation of intervention strategy based on CMV-specific immune responses after allogeneic SCT.

Late occurring CMV disease is an important problem after allogeneic SCT and has been associated with poor CMV-specific immunity. We conducted a prospective study of 58 patients studied at 3-6 months after allo-SCT, to base the antiviral therapy on monitoring of CMV-specific immunity. Reactivation of CMV was measured by quantitative PCR, and intracellular IFN-gamma production was analysed by FACS and enzyme-linked immunospot. Antiviral therapy was deferred in patients with documented CMV-specific immunity without symptoms of CMV disease or severe GVHD. Nineteen episodes of CMV reactivation were assessable. The strategy was correctly applied in 16/19 episodes. Therapy was deferred in 5/19 (none of these patients developed CMV disease) and was given according to the strategy in 11/19 episodes. Two patients received antiviral therapy despite having T cell-specific immunity. There was a tendency that patients with late CMV reactivation had weak CD8 T cell immunity at 3 months (P=0.06). The donors' serostatus influenced the strength of both CD4 and CD8 immunity at 3 months after SCT (P<0.01). There was no effect as regards the type of conditioning, donor type, stem cell source or acute GVHD. Monitoring the immunity of SCT patients may allow more targeted use of antiviral therapy.

Fludarabine-based disease-specific conditioning or conventional myeloablative conditioning in hematopoietic stem cell transplantation for treatment of non-malignant diseases.

Fludarabine-based conditioning (FBC) was given to 24 patients and conventional myeloablative conditioning (MC) to 33 patients, most children, before hematopoietic stem cell transplantation (HSCT) for non-malignant diseases. The donors were human leukocyte antigen (HLA)-A, -B, -DRbeta1-identical related (33%) or unrelated (67%). In the FBC group, two grafts failed versus three in the MC group; all were successfully regrafted. Fever was more common in the MC patients (P=0.003). Bacteremia occurred in 25% of the FBC group and 50% in the MC group (P=0.1). In the FBC group, platelet engraftment was faster and transfusions were fewer (P<0.05). Mucositis and renal function were similar in the two groups. The MC group had higher maximum bilirubin (P=0.03) and less often normal spirometry (P=0.04) after HSCT. A 7-year-old girl in the MC group had permanent alopecia. No patients had severe acute graft-versus-host disease (GVHD). Chronic GVHD was rare. Complete donor CD3+ chimerism was more common in the MC group (P=0.01), but CD33+ engraftment was better with FBS (P=0.03). Treatment-related mortality was 4 and 15%, and 5-year survival was 89 and 85% in the FBC and MC groups. Although survival was similar, FBC is a promising alternative to MC in non-malignant disorders.

Impact on the cytomegalovirus (CMV) viral load by CMV-specific T-cell immunity in recipients of allogeneic stem cell transplantation.

Patients experience cytomegalovirus (CMV) reactivation after stem cell transplantation (SCT) and need repeated courses of pre-emptive therapy. Analysis of CMV-specific immunity might help to assess the need for antiviral therapy. Forty-eight patients were studied during the first 3 months after SCT. Peripheral blood lymphocytes were stimulated by CMV antigen, and interferon (INF)-gamma production by CD3+ and CD4+ T cells was analysed. Results were correlated to transplant factors and CMV disease. Patients with INF-gamma production by CD3+ cells at 4 weeks after SCT had lower peak viral loads than patients with no such production (P=0.03). There was a similar tendency as regards CD4+ cells (P=0.09). Patients who underwent reduced-intensity conditioning (RIC) more frequently had CD3+ (48%) and CD4+ immunity (56%) 4 weeks after SCT compared with patients who received myeloablative conditioning (CD3+ 25%; CD4+ 35%). There was no effect of stem cell source, donor type or acute graft-versus-host disease. Three of 48 patients developed CMV disease and none of them had detectable INF-gamma production. CMV-specific T-cell response is associated with a lower rate of CMV replication. RIC results in improved T-cell reconstitution. Recovery of CMV-specific immunity might be delayed in patients with CMV disease. These observations suggest that detection of CMV-specific T-cells is useful in assessing the immunity against CMV.

Successful renal transplantation in patients with chronic granulomatous disease.

Chronic granulomatous disease (CGD) is a genetic disease caused by structural mutations in the enzyme NADPH oxidase that results in severe immunodeficiency. End-stage renal disease occurs in this patient population, and is often attributed to the necessary use of nephrotoxic anti-infectives. In this report, we present the experiences of two centers in transplantation of three patients with CGD: one transplanted with CGD, one cured of his CGD with bone marrow transplantation who subsequently underwent kidney transplantation and one that received a kidney transplant prior to being cured of CGD via a sequential peripheral blood stem cell transplant (SCT). All three recipients have enjoyed excellent outcomes. Their courses demonstrate the absolute requirements for a multidisciplinary and compulsive approach before, during and after transplantation. These case reports also highlight the unexpectedly benign effects of immunosuppressive therapy in this patient population.

Long-term immunity to poliovirus after vaccination of allogeneic stem cell transplant recipients.

Revaccination with poliovirus after allogeneic stem cell transplant (SCT) is usually effective, but the longevity of this immunity is unknown. Therefore, poliovirus immunity was studied in 134 patients having survived at least 5 years after vaccination. The median follow-up from vaccination was 8 years (1-19 years). In all, 21 (15.6%) patients had become seronegative to at least one of the poliovirus serotypes during follow-up. The estimated probabilities of remaining immune to poliovirus at 5 and 10 years after vaccination were 94 and 94% for subtype 1, 98 and 94% for subtype 2, and 93 and 90% for subtype 3, respectively. In multivariate analysis, the only risk factor for loss of immunity was younger patient age (P < 0.01), and there was a strong trend for patients with chronic GVHD to lose immunity more rapidly (P = 0.07). A total of 14 patients received a booster dose of an inactivated poliovirus vaccine and all responded. We conclude that poliovirus immunity is retained long term after revaccination in most patients after allogeneic SCT.

Measles immunity after allogeneic stem cell transplantation; influence of donor type, graft type, intensity of conditioning, and graft-versus host disease.

During follow-up after allogeneic stem cell transplantation (SCT), patients frequently lose their immunity to infectious agents such as measles. The aim of this study was to analyze the influence of different factors on measles immunity. In total, 395 patients with a disease-free survival of at least 1 year were included. Measles vaccination was given at 2 years after SCT to children and young adults without chronic GVHD or ongoing immunosuppression. In all, 264 patients had matched sibling donors and 131 either mismatched family or unrelated donors. Totally, 318 patients received bone marrow and 77 peripheral blood stem cells. Overall, 375 patients had undergone myeloablative and 20 nonmyeloablative conditioning. Out of 395 patients, 133 (34%) were seronegative to measles. In multivariate models, younger age or being vaccinated to measles, rather than previous measles disease, before transplantation were risk factors both for becoming seronegative and to have doubtfully protective immunity to measles. Acute GVHD grade II-IV was a risk factor for seronegativity and blood stem cells a risk factor for doubtfully protective immunity. Children and young adults previously immunized to measles have a high risk for becoming vulnerable to a measles infection. Since measles is again circulating in many countries and measles is a serious infection after SCT, vaccination should be considered.

Treosulfan/fludarabine: a new conditioning regimen in allogeneic transplantation.

Recently, the water-soluble bifunctional alkylating agent treosulfan demonstrated broad stem cell toxicity, immunosuppressive as well as antileukemic activity. Due to its well known low non-hematologic toxicity profile, treosulfan was considered an alternative agent for conditioning prior to allogeneic transplantation. A first clinical study, combining 3 x 10 g/m2 of treosulfan with 5 x 30 mg/m2 of fludarabine, demonstrated the feasibility of this conditioning. A fast, reliable and complete development of the donor hematopoiesis was evident as well as a low non-hematologic toxicity, transplantation-related mortality and relapse rate. In a second study treosulfan was escalated from 3 x 10 to 3 x 12 and 3 x 14 g/m2. In this protocol, 55 pts (patients) not amenable to standard conditioning suffering from various hematological malignancies were included. Complete donor chimerism was reached by day 28 in 80% of the pts. So far, 8 pts (11%) died without disease progression and 11 pts (20%) relapsed. Treosulfan was very well tolerated. Especially no hepatic VOD, severe cardiac or pulmonary toxicity was noted. Acute GvHD (degrees 11-IV) occurred in 44% and chronic GvHD in 45% of pts. Considering the poor prognosis of these study populations, treosulfan-based conditioning is considered to be safe and efficient. New phase 11 clinical protocols in AML and MDS will be initiated.

Is it safe to treat allogeneic stem cell transplanted recipients at home during the pancytopenic phase? A pilot trial.

BACKGROUND: After myeloablative treatment and allogeneic stem cell transplantation (ASCT), patients are kept isolated in the hospital to prevent infections during neutropenia. METHODS: So far, 22 patients have been given the choice of being treated at home. Eleven could not be treated at home, and they served as controls. Most of them had haematological malignancies. The donors were 12 HLA-compatible unrelated, 9 HLA-identical siblings and one twin. RESULTS: In the home care group, 3 developed bacteraemia, compared to 9 in the controls (p<0.01). The patient in the home care group had fewer days on total parenteral nutrition (median 3 vs. 24, p<0.001), required fewer erythrocyte transfusions (median 4 vs. 8, p=0.01), fewer days on i.v. antibiotics (median 6 vs. 13 days), and on analgesics (median 0 vs. 15) than the controls (p<0.05). Days with fever, time to engraftment, days with G-CSF and acute GVHD were the same in the two groups. 7/11 patients treated at home were readmitted to the ward for median 3 (0-7) days, due to fever or lack of a caregiver at home. Days to discharge to the out-patient clinic was faster in the group treated at home (median 20 vs 35 days, p<0.01). DISCUSSION: Patients who were treated at home enjoyed being active and taking a walk when they felt like it. This preliminary report suggests that home care after ASCT is not only safe, but better than isolation in the hospital.

N-acetyl-L-cysteine does not affect the pharmacokinetics or myelosuppressive effect of busulfan during conditioning prior to allogeneic stem cell transplantation.

Busulfan is currently used as a main component in the conditioning regimen prior to allogeneic stem cell transplantation (SCT). Several studies have shown a correlation between exposure to busulfan and transplantation-related liver toxicity, such as venoocclusive disease (VOD) in patients undergoing SCT. Busulfan is metabolized mainly through glutathione (GSH). During high-dose therapy, busulfan may deplete hepatocellular levels of GSH. As part of the conditioning therapy, busulfan is usually followed by high doses of cyclophosphamide. The activation of cyclophosphamide yields a cytotoxic metabolite, 4-hydroxy cyclophosphamide, which is highly reactive and detoxified through GSH. According to recent studies using cell lines and animal models N-acetyl-L-cysteine (NAC), a GSH precursor, does not hamper the myeloablative effect of busulfan during conditioning. In the present study, we administered NAC during conditioning to 10 patients at risk of VOD due to pretransplant liver disorders or elevated liver enzymes. No side effects related to the NAC infusions were observed and busulfan concentrations were not affected. All patients became pancytopenic and engrafted with 100% donor cells. None of the patients developed VOD or liver failure. Increased liver enzymes during conditioning decreased or normalized in all patients. We suggest that NAC therapy is safe and does not impair the myeloablative effect of busulfan during conditioning prior to SCT.

G-CSF given after haematopoietic stem cell transplantation using HLA-identical sibling donors is associated to a higher incidence of acute GVHD II-IV.

The effect of granulocyte colony-stimulating factor (G-CSF), given after transplantation, was studied in 155 patients transplanted with haematopoietic stem cells (HSCT) from HLA-identical sibling donors at Huddinge University Hospital between 1993 and 2001. Only patients with haematological malignancies were included. Conditioning consisted of total-body irradiation in 118 and busulphan in 37 patients. They were all given methotrexate combined with cyclosporine as graft-versus-host disease (GVHD) prophylaxis. Of the 155 patients, 66 (43%) received G-CSF after HSCT. Those given G-CSF had a significantly shorter time to neutrophil engraftment (P <0.001). G-CSF treatment had no effect on erythrocyte transfusions, platelet engraftment and infections. However, patients treated with G-CSF had a significantly higher incidence of grades II-IV acute GVHD than those not given this treatment (34 vs 9%, P <0.001). The multivariate analysis showed that the effect of G-CSF was independent of other known risk factors for grades II-IV acute GVHD. Death from GVHD occurred in four and two cases (P=0.06) in the two groups, respectively. The cumulative incidences of transplant-related mortality, survival, chronic GVHD, relapse and relapse-free survival were similar in both groups. In conclusion, G-CSF given after HLA-identical sibling HSCT was associated with a higher risk of grades II-IV acute GVHD, but not transplant-related mortality.

The effect of metronidazole on busulfan pharmacokinetics in patients undergoing hematopoietic stem cell transplantation.

Busulfan (Bu) is an important component of some myeloablative regimens prior to stem cell transplantation (SCT). Over the last few years it has been shown that other drugs administered concomitantly can influence Bu pharmacokinetics. In the present study, we compared Bu concentrations (trough levels) in three groups of patients. Group A (n=5) received metronidazole as graft-versus-host disease prophylaxis during Bu treatment. Group B (n=9) received Bu only for 2 days followed by 2 days of Bu and metronidazole. Group C (n=10) was a control group that received Bu without metronidazole. The mean Bu levels for Group A receiving metronidazole during conditioning was significantly (P<0.001) higher (948+/-280 ng/ml), compared to those observed in the control group (507+/-75 ng/ml). In Group B, the administration of metronidazole resulted in a significant (P<0.001) increase in Bu levels (807+/-90 ng/ml) during the last 2 days, compared to 452+/-68 ng/ml during the first 2 days. In Group A, one patient died with multiorgan failure, three experienced veno-occlusive disease (VOD) and one developed hemorrhagic cystitis. Elevated liver transaminases (AST, ALT) and bilirubin were detected in all Group A patients. In Group B, six patients had elevated liver function tests but no VOD was observed. We conclude that metronidazole should not be administered simultaneously with Bu to avoid the high plasma levels of Bu, which may lead to severe toxicity and/or treatment related mortality.

A phase II trial of liposomal busulphan as an intravenous myeloablative agent prior to stem cell transplantation: 500 mg/m(2) as a optimal total dose for conditioning.

We conducted a phase I/II trial, to evaluate the efficacy and safety of an intravenous liposomal formulation of busulphan (LBu) as a myeloablative agent for stem cell transplantation (SCT). The liposomal busulphan was administered as a 3 h infusion twice daily over 4 consecutive days. Six adults received 1.6-2 mg/kg/dose and 18 children received 1.8-3 mg/kg/dose. Pharmacokinetic parameters were studied after the first and the last dose of busulphan. No significant difference in clearance, AUC, elimination half-lives or distribution volume between the first and the last dose was found in either groups. A significantly (P < 0.005) higher clearance was observed in children after the first and the last dose (3.61 and 3.79 ml/min/kg, respectively) compared to adults (2.40 and 2.33 ml/min/kg, respectively). The elimination half-lives after the first and the last dose were significantly (P < 0.005) shorter in children (2.59 and 2.72 h, respectively) compared to adults (3.35 and 3.61 h, respectively). Clearance correlated significantly with age. However, no significant correlation with age was observed when clearance was adjusted to the body surface area. Two cases of VOD following a total dose of 24 mg/kg were observed. Six patients experienced mucositis. No other organ toxicity was observed. We conclude that intravenous liposomal busulphan pharmacokinetics is age dependent. A dosage schedule based on body surface area should be used especially in young children to reduce the age-dependent difference in kinetics. An intravenous liposomal dose of busulphan of 500 mg/m(2) is suggested to reach a similar systemic exposure and myeloablative effect in both children and adults. Moreover, the novel liposomal form of busulphan showed a favorable toxicity profile and seems safe as a part of the high-dose therapy prior to SCT.

The graft-versus-leukaemia effect in haematopoietic stem cell transplantation using unrelated donors.

We studied the graft-versus-leukaemia (GVL) effect in 185 patients with haematological malignancies who underwent unrelated donor haematopoietic stem cell transplantation (HSCT) at Huddinge University Hospital between May 1991 and June 2001. Ninety-five were in first CR/CP and 90 in later stages. Most (86%) of them had a HLA-A, -B and -DRbeta1 matched donor. Conditioning usually consisted of total body irradiation and cyclophosphamide, and GVHD prophylaxis of cyclosporine and methotrexate. In the multivariate risk-factor analysis of relapse, we found that disease stage beyond CR1/CP1 (P = 0.02), acute GVHD 0-I (P = 0.02), absence of chronic GVHD (P = 0.02) and ALL (P = 0.02) were independent risk factors for relapse. The incidence of relapse in those with acute GVHD grade II was 18% vs 46% in those with no or grade I (P = 0.04). In patients with or without chronic GVHD, the incidences of relapse were 32% and 48%, respectively (P < 0.01). The best RFS was seen in patients with chronic GVHD. No difference in RFS was seen in patients with no, mild or moderate acute GVHD. Risk factors for relapse after HSCT with unrelated donors were: acute lymphoblastic leukaemia, disease stage beyond CR1/CP1, absence of chronic GVHD and no, or mild acute GVHD. Overall and relapse-free survival were not improved by the occurrence of acute GVHD.

Cytolytic T cell reactivity to Epstein-Barr virus is lost during in vitro T cell expansion.

In the setting of allogeneic hematopoietic stem cell transplantation, ex vivo culturing of donor T lymphocytes is a necessary step for processes such as gene modification. Often the aim is to enable control of undesired alloreactivity after in vivo administration of the cultured cells. However, it is not fully understood how T cell reactivity against donor and third-party targets is affected by the ex vivo cell culturing process. We have assessed how the activity of anti-Epstein Barr virus (EBV)-specific T lymphocytes from healthy EBV-seropositive donors is affected by in vitro cell culturing. Peripheral blood mononuclear cells (PBMCs) were expanded in X-VIVO 15 culture medium supplemented with 5% human serum. The cells were stimulated by either OKT3 (10 ng/ml) and interleukin (IL)-2 (500 U/ml) or by using anti-CD3/CD28-coated immunomagnetic beads and IL-2 (100 U/ml). Induction of polyclonal EBV-specific cytotoxic T lymphocyte cultures was attempted by stimulation of the in vitro-expanded cells at different time points during the cell expansion process, with pre-established autologous EBV-transformed lymphoblastoid cell lines (LCLs). While EBV-specific cytotoxic T lymphocytes (CTL) were generated from untreated PBMCs of 5 healthy donors, EBV-specific cytotoxicity was significantly decreased or absent in CTL cultures established from in vitro-expanded PBMCs. Our results indicate that the ex vivo cell expansion process itself significantly reduces the activity and/or the number of EBV-specific T cells. Additional stimulation with CD28 antibodies could not prevent this effect. Because T cell depleted bone marrow or stem cell grafts are known to contribute to the development of post transplant lymphoproliferative disorders, this should be taken into consideration if one considers expanding and administering PBMCs in conjunction with a T cell-depleted stem cell grafts.