Safety and efficacy of liposomal amphotericin B in allogeneic bone marrow transplant recipients

Improved survival after allogeneic hematopoietic stem cell transplantation in recent years. A single-center study

We analyzed the outcome of allogeneic hematopoietic stem cell transplantation (HSCT) over the past 2 decades. Between 1992 and 2009, 953 patients were treated with HSCT, mainly for a hematologic malignancy. They were divided according to 4 different time periods of treatment: 1992 to 1995, 1996 to 2000, 2001 to 2005, and 2006 to 2009. Over the years, many factors have changed considerably regarding patient age, diagnosis, disease stage, type of donor, stem cell source, genomic HLA typing, cell dose, type of conditioning, treatment of infections, use of granulocyte-colony stimulating factor (G-CSF), use of mesenchymal stem cells, use of cytotoxic T cells, and home care. When we compared the last period (2006-2009) with earlier periods, we found slower neutrophil engraftment, a higher incidence of acute graft-versus-host disease (aGVHD) of grades II-IV, and less chronic GVHD (cGHVD). The incidence of relapse was unchanged over the 4 periods (22%-25%). Overall survival (OS) and transplant-related mortality (TRM) improved significantly in the more recent periods, with the best results during the last period (2006-2009) and a 100-day TRM of 5.5%. This improvement was also apparent in a multivariate analysis. When correcting for differences between the 4 groups, the hazard ratio for mortality in the last period was 0.59 (95% confidence interval [CI]: 0.44-0.79; P < .001) and for TRM it was 0.63 (CI: 0.43-0.92; P = .02). This study shows that the combined efforts to improve outcome after HSCT have been very effective. Even though we now treat older patients with more advanced disease and use more alternative HLA nonidentical donors, OS and TRM have improved. The problem of relapse still has to be remedied. Thus, several different developments together have resulted in significantly lower TRM and improved survival after HSCT over the last few years.

A prospective randomized controlled trial comparing PCR-based and empirical treatment with liposomal amphotericin B in patients after allo-SCT

We compared the efficacy and safety of empirical plus PCR-based vs empirical liposomal amphotericin B treatment after Allo-SCT. Allo-SCT recipients were randomized to receive either PCR-based preemptive therapy (group A; n=198) or empirical antifungal therapy (group B; n=211) with liposomal amphotericin B. In group A, therapy was started after one positive PCR result or after 120 h of febrile neutropenia refractory to broad-spectrum antibacterial therapy. In group B, liposomal amphotericin B was started after 120 h of refractory febrile neutropenia. Demographic and clinical characteristics were well balanced. A total of 112 (57.1%) patients in group A and 76 (36.7%) patients in group B received antifungal therapy (P<0.0001). Twelve patients in group A and 16 patients in group B developed proven invasive fungal infection (IFI). Survival curves showed better survival until day 30 when close PCR monitoring was performed (mortality 1.5 vs 6.3%; P=0.015), but there was no difference at day 100. At day 100, no difference was observed in the incidence of IFI (primary end point) and survival between the two arms. Further studies are required to assess the benefit of using PCR in patients after SCT.

Costs of allogeneic hematopoietic cell transplantation with high-dose regimens

To characterize the costs of allogeneic hematopoietic cell transplantation with high-dose regimens (HDCT), we analyzed clinical information and costs of 315 HDCT recipients during a 4-year study period beginning in 2000. Multivariate analyses were performed to identify pre- and/or post-HDCT factors predicting higher costs within the first year. Overall survival (OS) at 100 days and 1 year were 80% and 58%, respectively. The median cost and days of hospitalization were $102,574 in 2004 US dollars and 36 days in the hospital for 100 days, and $128,800 and 39 days in the hospital for 1 year. Early costs, defined as costs within the first 100 days, accounted for 84% of total costs within the first year. Inpatient costs comprise 94% of the early costs, but only 61% of the later costs defined as costs incurred between 101 days and 1 year. Of the pre-HDCT factors, unrelated donors and advanced disease risk were significantly associated with increased cost. When post-HDCT events were also considered, these pre-HDCT factors were no longer independently predictive of high cost. Instead, severe complications post-HDCT were associated with higher costs, increasing total costs $20,228 on average. If no complications occurred, the mean cost within the first year was $79,222. These results provide cost estimates for complicated and uncomplicated HDCT procedures, as well as costs for management of specific transplant complications.

Effect of prophylaxis on fungal infection and costs for high-risk liver transplant recipients

We sought to determine whether the prophylactic use of amphotericin B products (conventional amphotericin B and liposomal amphotericin B) reduces the incidence of fungal infections in high-risk liver transplant recipients, and if so, whether this lowers the cost of care. The study sample comprised 232 adult orthotopic liver transplants performed from 1994 to 2005 at a single center for patients classified as being at high risk for fungal infections. High-risk patients who received transplants with a prophylaxis regimen of amphotericin B (n=58 transplants) were compared with high-risk patients who received no prophylaxis (n=174 transplants). Fungal infections occurred in 3 transplants (5.17%) of those who received amphotericin B and 28 transplants (16.09%) in those without prophylaxis (P=0.0432). Regression models were used to analyze fungal infection and costs for the 232 high-risk transplants. Failure to offer prophylaxis conferred a 4-fold greater risk of fungal infection (P=0.046) compared with those who received amphotericin B. A fungal infection in a high-risk recipient increased mean costs by 46.48%. The indirect effect of prophylaxis (operating through infection reduction) is estimated to reduce overall costs in high-risk patients by 8.73%.

Adverse effects of antifungal therapies in invasive fungal infections: review and meta-analysis

Amphotericin B is the main therapeutic agent for the treatment of invasive fungal infections; however, it is associated with significant toxicities that limit its use. Other systemic antifungal agents have been developed to improve tolerability while maintaining the efficacy profile of conventional amphotericin B. Fifty-four studies involving 9,228 patients were assessed for the frequency of adverse effects of the main systemic antifungal agents. While the results suggest that liposomal amphotericin B is the least nephrotoxic of the lipid formulations (14.6%), that conventional amphotericin B is the most nephrotoxic (33.2%), and that itraconazole is the most hepatotoxic (31.5%), the lack of standard definitions of antifungal-related adverse effects limits the validity of these results. Furthermore, heterogeneous patient pools and differing protocols make it difficult to draw direct comparisons between studies. With the advent of newer classes of systemic antifungal agents, future trials should conform to definitions that are universally applicable and clinically relevant to allow for such comparisons and to enable evidence-based decision-making.

Treatment Costs and Survival in Patients with Grades III-IV Acute Graft-Versus-Host Disease after Allogenic Hematopoietic Stem Cell Transplantation During Three Decades

To determine development of treatment, costs, and survival for patients with grades III/IV acute graft-versus-host disease (GVHD), data from 88 patients with grades III/IV acute GVHD were collected. The patients were divided into three groups: patients who received transplants from 1977 through 1989 (group A), 1990 through 1999 (group B), and 2000 through 2004 (group C). The costs for treatment, enumerated to year 2003 costs, were calculated. An increased 1-year survival rate was found in group C, at 21% versus 9% and 8% for groups A and B, respectively (P=0.02). Death by acute GVHD was increased by repeat transplantation (P<0.001), grade IV acute GVHD (P<0.001), human leukocyte antigen mismatch (P=0.009), and transplantation before 2000 (P=0.015). Transplantation after 1990 (P=0.003) and grade IV acute GVHD (P=0.03) were associated with higher treatment costs. It was found that the time the patients had GVHD did not differ among the three groups. In conclusion, the costs and survival rates associated with severe acute GVHD has increased in recent years.

Allogeneic hematopoietic stem cell transplantation: state of the art and new perspectives

Allogeneic hematopoietic stem cell transplantation (ASCT) is a well-established therapy for leukemias and other immunohematopoietic disorders. In more recent years, bone marrow as stem cell source has been replaced by peripheral blood stem cells, which results in faster engraftment. Cord blood grafts are increasingly used. Conditioning prior to transplant may be myeloablative or nonmyeloablative. The latter is used preferentially in patients with high age or organ impairment. Isolation in the hospital during posttransplant pancytopenia has been challenged by promising results using home care. PCR diagnosis and new antifungal and antiviral treatment have reduced morbidity and mortality. The major threat to a successful outcome after ASCT is leukemic relapse. PCR techniques to detect recipient cells in the leukemic cell lineage or minimal residual disease enable early detection of leukemic cells. Donor lymphocyte infusions have an antileukemic effect. ASCT has shown an antitumor effect in metastatic cancers from breast, kidney, colon, ovaries, prostate and pancreas. Mesenchymal stem cells may be derived from bone marrow and have the capacity to differentiate into several mesenchymal tissues, such as bone, cartilage and fat. They seem to escape the immune system and have immunomodulatory effects in vitro and in vivo. To conclude, ASCT is a potent immunotherapy.

Assessment of nephrotoxicity of high-cumulative dose of liposomal amphotericin B in a pediatric patient who underwent allogeneic bone marrow transplantation

We describe a 9-yr-old boy who received the highest cumulative dose so far reported of liposomal amphotericin B. The patient underwent an allogeneic bone marrow transplantation (BMT) for adrenoleucodystrophy, after a conditioning regimen with busulfan, thiothepa and cyclophosphamide. Rabbit antithymoglobulin, cyclosporin and prednisone were used as prophylaxis against graft vs. host disease (GVHD). Post-transplant Epstein-Bar-virus-related lymphoma was diagnosed on day +68 and was treated with donor-derived lymphocytes. The patient developed a severe form of GVHD, and a progressive worsening of his neurological status because of progression of his underlying disease. Death from septic shock occurred 23 months after BMT. During prolonged hospitalization, 19,750 mg of liposomal amphotericin B, about 1000 mg/kg, were given for prophylactic or empirical therapeutic purposes without significant nephrotoxicity. This case suggests that liposomal amphotericin B is safe and well-tolerated even if is administered for long periods and a cumulative dose fivefold greater than the nephrotoxic threshold of amphotericin B deoxycholate is achieved.

Schmerzloser Ikterus nach Urlaub in Tansania

The side effects caused by malaria prophylaxis with mefloquine (Lariam) are well known. We describe the case of a 42-year-old female Caucasian patient suffering from painless jaundice and showing elevated liver, cholestasis and inflammation laboratory findings 7 days after returning from Tanzania. Acute cholecystitis was diagnosed by ultrasound. Treatment with parenteral nutrition and antibiotic therapy did not show any beneficial effect. Excluding the possibility of infectious diseases, the elevated laboratory and ultrasound findings were normalized after the discontinuation of the malaria prophylaxis.

Adverse effects of antifungal therapies in invasive fungal infections: review and meta-analysis

Amphotericin B is the main therapeutic agent for the treatment of invasive fungal infections; however, it is associated with significant toxicities that limit its use. Other systemic antifungal agents have been developed to improve tolerability while maintaining the efficacy profile of conventional amphotericin B. Fifty-four studies involving 9,228 patients were assessed for the frequency of adverse effects of the main systemic antifungal agents. While the results suggest that liposomal amphotericin B (L-AmB) is the least nephrotoxic of the lipid formulations (14.6%), that conventional amphotericin B (AmB) is the most nephrotoxic (33.2%), and that itraconazole is the most hepatotoxic (31.5%), the lack of standard definitions of antifungal-related adverse effects limits the validity of these results. Furthermore, heterogeneous patient pools and differing protocols make it difficult to draw direct comparisons between studies. With the advent of newer classes of systemic antifungal agents, future trials should conform to definitions that are universally applicable and clinically relevant to allow for such comparisons and to enable evidence-based decision-making.

Liposomal amphotericin B (AmBisome) for fungal infections in immunocompromised adults and children

Invasive fungal infections are rare but life-threatening infections, most often occurring in immunocompromised patients. For a long time, Amphotericin B has been the best choice for treatment, because it is fungicidal with a broad antifungal spectrum and minimal risk of resistance development. The therapeutic use of amphotericin B has, however, been limited by its toxicity-both acute as well as chronic. To counter this, amphotericin B has been encapsulated in liposomes, which reduces its toxicity and allows higher doses to be given. Ambisome is a true, spherical, small unilamellar liposome with a median size of 80 nm. The pharmacokinetic profile was changed, and the maximum concentration and AUC of amphotericin B after AmBisome treatment were greater than those found with the conventional drug. The highest tissue concentrations of AmBisome were found in the liver and spleen, and less than 1% of the administered dose was recovered in other organs. At Huddinge University Hospital, we were the first to use and report on the experience of AmBisome. We now have more than 12 years' experience in transplant recipients, with a good safety profile, improved rate of curing mycological proven infections and reduced mortality in fungal infections. In two placebo-controlled prophylactic trials, we found that AmBisome was effective for preventing fungal colonization and invasive fungal infections, respectively, in allogeneic stem cell and liver transplantation. In uncontrolled and, more recently, in randomized controlled studies at other centers, AmBisome has revealed less toxicity and an efficacy equal or superior to that of the conventional drug in treating neutropenia-associated fever and proven invasive fungal infections in both adults as well as in children. Although investigators tend to increase the dose used, the optimal dose for probable or proven infection is still under debate. Based on our own experience in using AmBisome and the experience at other centers, we can conclude that AmBisome represents a major breakthrough in the treatment of invasive fungal infections, especially in immunocompromised patients.

Treatment of severe acute graft-versus-host disease with anti-thymocyte globulin

Severe acute graft-versus-host disease (GVHD) is one of the major complications after haematopoietic stem-cell transplantation (HSCT). Treatment of severe GVHD is difficult and the condition is often fatal. One proposed method of improving the therapy is to include anti-thymocyte globulin (ATG). Here, we will report our results in 29 patients using ATG as part of treatment for severe steroid-resistant acute GVHD. Four patients suffered from grade II, 13 from grade III and 12 from grade IV GVHD. Median time to grade II GVHD was 24 d (range 7-91 d) and to grade III was 29 d (range 8-55 d) after HSCT. Five different ATG preparations were used, rabbit ATG (R-ATG), BMA 031, OKT3, ATG-Fresenius and Thymoglobuline. All patients had skin involvement, 26 also had gut involvement and 25 had liver involvement. The rate of response to treatment was best in skin involvement (72%), while liver and gut involvement showed lower response rates (38%). Eleven patients survived more than 90 d, 7 of them developed chronic GVHD, 1 developed mild GVHD, 1 developed moderate GVHD and 5 developed severe GVHD. Survival at 100 d was 37% and at 1 yr it was 12%. Most patients died of GVHD, with virus or fungal infections as contributing causes of death. To conclude, treatment of severe acute GVHD is difficult and ATG, in our hands, adds nothing to conventional pharmacological treatment.

Comparison of amphotericin B lipid complex (ABLC) vs. ambisome in the treatment of suspected or documented fungal infections in patients with leukemia

Fungal infections remain a major cause of treatment failure and death in acute leukemia. New liposomal preparations of amphotericin B are now available. While less toxic, their comparative efficacy and toxicity profiles are unknown. In this study the comparative efficacy and safety of ABLC vs. AmBisome was evaluated in seventy-five patients with leukemia who developed 82 episodes of suspected or documented mycosis, and were treated (1:1) with either ABLC (n=43) or AmBisome (n=39). Both drugs were dosed accordingly from 3 to 5 mg/kg/day. Using an intent-to-treat analysis, the overall response to therapy was 27/43 (63%) for ABLC and 15/39 (39%) for AmBisome (p=0.03). Median dose and duration of treatment was 10 days at 3 mg/kg for ABLC and 15 days at 4 mg/kg for AmBisome. Acute, not dose-limiting infusion side effects were seen in 70% vs. 36% (p=0.002), ABLC vs. AmBisome. Increase of bilirubin > 1.5 times from baseline was 38% vs. 59%, ABLC vs. AmBisome (p=0.05). ABLC and AmBisome were equally effective for the treatment of suspected or documented fungal infections. While, acute infusion-toxicity was greater with ABLC, infusion toxicity requiring discontinuation was similar for both drugs. AmBisome was better tolerated than ABLC but was associated with mild abnormalities in liver function tests at the end of therapy.

A strategy for managing fungal infections in haematopoietic stem cell transplantation

As more indications continue to be found for allogeneic haematopoietic transplantation, more patients are at risk for invasive fungal infectious diseases (IFID), particularly candidiasis and aspergillosis. Risk factors for disease are becoming better defined and diagnostic methods have improved considerably. In addition, there is now international agreement that three elements form the basis for defining IFID (host factors, clinical evidence, and mycological results), that imaging is acceptable for diagnosing disease, and that indirect tests such as antigen detection are also adequate mycological proof of cause. There are also more drugs available and still more to come, offering the potential for selective prophylaxis as well as preemptive and specific therapy, as well as for flexible administration. Hence, all the elements are in place for designing and testing an effective and economically sound strategy for dealing with IFID.

Aspergillosis in bone marrow transplant recipients

Invasive aspergillosis in bone marrow transplant recipient is associated with a high mortality. Diagnosis is often delayed because the inflammatory response is blunted by immunosuppression. The gold standard of tissue biopsy is often considered too in invasive as the procedure is often complicated by bleeding and secondary infection. Recent finding on non-invasive tests such as serial measurement of peripheral blood galactomannan antigen or DNA appears to be promising. However, the limited availability of such tests and requirement for expertise are still hampering their use in routine clinical management. More often than not, initiation of antifungal therapy is empirical and based on suggestive radiological changes. Amphotericin B remains the gold standard of therapy but liposconal preparation may prove to be less nephrotoxic and equally effective. Treatment outcome depends more on the acceleration of the recovery of the immune system and the reduction of anti-GVHD therapy than the antifungal agent followed by surgical resection. The efficacy of many reported anti-aspergillosis prophylactic regimen has not been proved in randomized control trials. Despite the absence of data, such policy should still be considered in transplant units with high incidence of aspergillus or undergoing renovation.

Antifungal agents. Part I. Amphotericin B preparations and flucytosine

Traditionally, amphotericin B has been the cornerstone of antifungal treatment. Toxicity, however, is a major dose-limiting factor of amphotericin B deoxycholate. Nevertheless, it continues to have a major role in the treatment of deep-seated mycotic infections. Recently, less nephrotic lipid formulations, including amphotericin B lipid complex, amphotericin B cholesteryl sulfate, and liposomal amphotericin B, have been introduced. The pharmacologic properties, main indications, recommended dosages, related costs, and adverse effects of these various preparations are summarized in this review. Orally administered flucytosine is useful in certain infections, particularly cryptococcal meningitis, but it should be used with caution in patients with renal insufficiency.

Results of different strategies for reducing cytomegalovirus-associated mortality in allogeneic stem cell transplant recipients

BACKGROUND

Several preventive strategies against cytomegalovirus (CMV) disease have been developed during the last decade. These have frequently been used in combination, and it has been difficult to identify each strategy's contribution.

METHODS

Risk factors for CMV disease, death in CMV disease and transplant-related mortality were analyzed in 584 patients, who underwent a total of 594 allogeneic bone marrow transplants.

RESULTS

The overall probability of CMV disease was 8.9%. No seronegative patient who had a seronegative marrow donor developed CMV disease. The corresponding probabilities for seronegative patients with seropositive donors, seropositive patients with seronegative donors, and seropositive patients with seropositive donors were 5.4%, 13.7%, and 11.7%, respectively. In multivariate Cox models, the use of preemptive antiviral therapy and being CMV-seronegative reduced the risk for CMV disease, CMV-associated death, and transplant-related mortality (TRM). Patients who received unrelated or mismatched family donor transplants had increased risks for CMV disease, CMV-associated death, and TRM. Older age was a significant risk factor for CMV disease and TRM. A total of 258 patients who were monitored by polymerase chain reaction for CMV DNA were analyzed separately to assess whether addition of another CMV preventive strategy could give benefit. Patients who received mismatched or unrelated donor transplants had increased risk for CMV disease, death in CMV disease, and TRM. High-dose acyclovir prophylaxis or addition of intravenous immune globulin had no influence.

CONCLUSIONS

Preemptive therapy based on polymerase chain reaction for CMV DNA was associated with reduced risks for CMV disease, CMV-associated death, and TRM, whereas other prophylactic modalities did not give additional benefit.

Low incidence of acute graft-versus-host disease, using unrelated HLA-A-, HLA-B-, and HLA-DR-compatible donors and conditioning, including anti-T-cell antibodies

BACKGROUND

Using unrelated bone marrow, there is an increased risk of graft-versus-host disease (GVHD).

METHODS

HLA-A-, HLA-B-, and HLA-DR-compatible unrelated bone marrow was given to 132 patients. The diagnoses included chronic myeloid leukemia (n=43), acute lymphoblastic leukemia (n=29), acute myeloid leukemia (n=27), myelodysplastic syndrome (n=4), lymphoma (n=3), myeloma (n=1), myelofibrosis (n=1), severe aplastic anemia (n=12), and metabolic disorders (n=12). The median age was 25 years (range 1-55 years). HLA class I was typed serologically, and class II was typed by polymerase chain reaction using sequence-specific primer pairs. Immunosuppression consisted of antithymocyte globulin or OKT3 for 5 days before transplantation and methotrexate combined with cyclosporine.

RESULTS

Engraftment was seen in 127 of 132 patients (96%). Bacteremia occurred in 47%, cytomegalovirus (CMV) infection in 49%, and CMV disease in 8%. The cumulative incidences of acute GVHD > or = grade II and of chronic GVHD were 23% and 50%, respectively. The 5-year transplant-related mortality rate was 39%. The overall 5-year patient survival rate was 49%; in patients with metabolic disorders and severe aplastic anemia, it was 61% and 48%, respectively. The disease-free survival rate was 47% in patients with hematological malignancies in first remission or first chronic phase and 38% in patients with more advanced disease (P=0.04). Acute GVHD was associated with early engraftment of white blood count (P=0.02). Poor outcome in multivariate analysis was associated with acute myeloid leukemia (P=0.01) and CMV disease (P=0.04).

CONCLUSION

Using HLA-A-, HLA-B-, and HLA-DR-compatible unrelated bone marrow and immunosuppression with antithymocyte globulin, methotrexate, and cyclosporine, the probability of GVHD was low and survival was favorable.

Allogeneic bone marrow transplantation for hematological malignancies--controversies and recent advances

Today more than 80000 allogeneic bone marrow transplantations (BMT) have been performed worldwide. The major indications are hematological malignancies such as acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), chronic myeloid leukemia (CML) and myelodysplastic syndromes. Unrelated donors are increasingly used and there are around 4 million volunteer donors available in different registers, the largest being the National Marrow Donor Program. Molecular typing has improved the typing technique which has resulted in a decreased risk of graft-versus-host disease (GVHD), lower transplant-related mortality (TRM) and improved leukemia-free survival (LFS). Using HLA-identical siblings, patients with AML in first complete remission (1 CR) and high-risk ALL in 1 CR are clear indications for BMT. However, if an HLA-identical sibling is not available, it is not known today if an unrelated bone marrow or autografting is the best option for all patients with acute leukemia in 1 CR. Because BMT is the only curable treatment for CML, a search for an unrelated donor should start as soon as it is evident that an HLA-identical sibling is not available. BMT within a year from diagnosis is of major importance for outcome. Allogeneic peripheral blood progenitor cells (PBPC) have been used as an alternative to bone marrow. Preliminary studies indicate a faster engraftment, but prospective randomized trials are necessary to establish the role of allogeneic PBPC. Umbilical cord blood has also been used as a source of allogeneic hematopoietic stem cells. Using cord blood from HLA-identical siblings, engraftment seems to be delayed, but the probability of GVHD is low. Preliminary data using unrelated cord blood cells are encouraging. GVHD has an important antileukemic effect. Recently, a graft-versus-myeloma and a graft-versus-breast-cancer effect has been demonstrated. In patients who relapse after BMT, donor lymphocytes can induce remission, especially in patients with CML. With molecular techniques it is possible to detect relapse at an early stage, so called minimal residual disease. Liposomal amphotericin B has few side-effects and decreased the death rate by invasive fungal infection in BMT recipients. Early diagnosis and treatment of cytomegalovirus (CMV) infection with new antiviral drugs have dramatically reduced the incidence and mortality in CMV disease. Cyclosporine combined with methotrexate is today the most widely used immunosuppressive regimen and has decreased GVHD and improved survival. However, several new immunosuppressive drugs need to be explored in clinical BMT. Immune modulation by for instance cytokines and cytokine inhibititors is a new exciting development.

Bone marrow transplantation using unrelated donors for haematological malignancies

Bone marrow transplantation from unrelated donors is increasingly used to treat haematological malignancies. There are almost 4 million volunteer donors now available. Therefore, it is possible to find an HLA-A, -B and -DR-identical donor for around 70% of the patients. The major obstacles to unrelated bone marrow transplantations have been rejection, severe acute graft-versus-host disease (GVHD) and prolonged immune recovery leading to frequent infections and a high transplant-related mortality. However, with improved tissue typing using DNA techniques, immunosuppression using T-cell depletion in vitro or in vivo, the frequency of acute GVHD is acceptable and the results approach those obtained with HLA-identical siblings. For patients with chronic myeloid leukaemia, the worldwide 3-year survival is around 40%. Other indications for bone marrow transplantation with unrelated marrow include acute leukaemia and myelodysplastic syndromes with high-risk features. Unrelated cord blood cells and unrelated peripheral blood progenitor cells will be increasingly used as alternative haematopoietic stem cell sources to bone marrow. Improved immunosuppression, more accurate tissue typing, growth factors and better management of infections is expected to improve outcome using unrelated haematopoietic stem cells for transplantation in the near future.