Allogeneic stem cell transplantation with reduced-intensity conditioning is potentially feasible as an outpatient procedure

A comparison of haploidentical versus HLA-identical sibling outpatient hematopoietic cell transplantation using reduced intensity conditioning in patients with acute leukemia

Background

Hematopoietic cell transplantation (HCT) increases survival for acute leukemia. Outpatient allogeneic HCT reduces costs and increases transplant rates in developing countries. We report outcomes of outpatient HLA-identical and haploidentical HCT in acute leukemia.

Methods

This single-center retrospective cohort study analyzed 121 adult patients with acute myeloblastic (AML) and acute lymphoblastic leukemia (ALL) receiving an outpatient allogeneic HCT with peripheral blood allografts after reduced-intensity conditioning (RIC) from 2012-2022.

Results

There were 81 (67%) haploidentical and 40 (33%) HLA-identical transplants. Complete chimerism (CC) at day +100 was not different in HLA-identical compared to haploidentical HCT (32.5% and 38.2%, P=0.054). Post-HCT complications, including neutropenic fever (59.3% vs. 40%), acute graft-versus-host-disease (aGVHD) (46.9% vs. 25%), cytokine release syndrome (CRS) (18.5% vs. 2.5%), and hospitalization (71.6% vs 42.5%) were significantly more frequent in haploidentical HCT. Two-year overall survival (OS) was 60.6% vs. 46.9%, (P=0.464) for HLA-identical and haplo-HCT, respectively. There was no difference in the 2-year disease-free-survival (DFS) (33.3% vs. 35%, P=0.924) between transplant types. In multivariate analysis, positive measurable residual disease (MRD) at 30 days (HR 8.8, P=0.018) and 100 days (HR 28.5, P=0.022) was associated with lower OS, but not with non-relapse mortality (NRM) (P=0.252 and P=0.123, univariate). In univariate analysis, both 30-day and 100-day MRD were associated with lower DFS rates (P=0.026 and P=0.006), but only day 30 MRD was significant in multivariate analysis (P=0.050). In the case of relapse, only MRD at day 100 was associated with increased risk in the univariate and multivariate analyses (HR 4.48, P=0.003 and HR 4.67, P=0.008). Chronic graft-versus-host-disease (cGVHD) was protective for NRM (HR 0.38, P=0.015). There was no difference in cumulative incidence of relapse (CIR) between transplant types (P=0.126). Forty-four (36.4%) patients died, with no difference between HCT type (P=0.307). Septic shock was the most frequent cause of death with 17 cases, with no difference between transplant types.

Conclusions

Outpatient peripheral blood allogenic HCT after RIC is a valid and effective alternative for adult patients suffering acute myeloblastic or lymphoblastic leukemia in low-income populations.

Graft-versus-host disease after an outpatient peripheral blood hematopoietic cell transplant using reduced-intensity conditioning: a single-center LATAM experience

BACKGROUND

HLA compatibility predicts allogeneic hematopoietic cell transplant (allo-HCT) and graft-versus-host disease (GvHD) outcomes. There is insufficient information regarding GvHD outcomes for outpatient HLA-identical and haploidentical-HCT employing reduced-intensity conditioning (RIC).

RESEARCH DESIGN AND METHODS

We compare GvHD outcomes between donor types and report risk factors associated with GvHD. Stem cell source was T-cell replete peripheral blood. GvHD prophylaxis was post-transplant cyclophosphamide (PT-CY), mycophenolic acid, and calcineurin inhibitors for haploidentical (n = 107) and oral cyclosporine (CsA) plus methotrexate i.v. for HLA-identical (n = 89) recipients.

RESULTS

One hundred and ninety-six HCT transplant patients were included. aGvHD and cGvHD frequency were similar between HCT types. aGvHD severity was comparable, but severe cGvHD was less frequent in the haploidentical group (p = .011). One-hundred-day cumulative incidence (CI) of aGvHD for haploidentical and HLA-identical was 31% and 33% (p = .84); 2-year CI of cGvHD was 32% and 38% (p = .6), respectively. Haploidentical recipients had less steroid-refractory cGvHD (p = .043). Patients with cGvHD had less 2-year relapse (p = .003); both aGvHD and cGvHD conferred higher OS (p = .010 and p = .001), respectively. Male sex was protective for steroid-refractory cGvHD (p = .028).

CONCLUSIONS

Acute and chronic GvHD rates were comparable between HLA-identical and haploidentical transplant groups. cGvHD severity was lower in the haploidentical group.

Outpatient Haploidentical Stem Cell Transplantation Using Post-Transplant Cyclophosphamide Is Safe and Feasible

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) feasibility has increased in the last decades because of haplo-HSCT, changes in chemotherapy schedules, and the possibility of an outpatient-based HSCT. The main barriers remain in low-middle income countries. There is a lack of information regarding haplo-HSCT with a myeloablative (MAC) regimen on an outpatient basis.

OBJECTIVES

Our primary objective was to determine if outpatient haplo-HSCT was feasible.

STUDY DESIGN

Single center, retrospective cohort, n=60 adult patients undergoing Haplo-HSCT. Descriptive statistical analysis, univariate and multivariate comparison.

PATIENTS AND METHOD

We analyzed 60 adult patients transplanted with an intended haplo-HSCT on an outpatient basis from 2015 to 2019 in our unit. A multivariate analysis was performed on risk factors for hospitalization.

RESULTS

Median age was 27 years (15-64). All patients underwent conditioning as outpatients, and none required hospitalization before day 0. Thirteen patients (21.6%) were followed completely in the outpatient clinic and 47 (78.3%) required hospitalization in a median of 3 days after infusion (range, 1-14). The median length of stay (LOS) was 8 days (IQR, 3-17). Fever secondary to cytokine release syndrome (CRS) was the most common reason for hospitalization occurring in 43/47 (91.5%), 4 were related to infection and 36 were related to CRS. In the univariate analysis, CRS, slower engraftment, and female sex were associated with the need for hospitalization. In the multivariate analysis, only CRS remained significant (OR 9.14 [95%CI, 1.58-56.46]). The 2-year overall survival (OS) was 41.7% for ambulatory transplant vs. 38% for those requiring hospitalization (P = 0.12). The 2-year event-free survival (EFS) was 33% for outpatient patients and 16.7% for those hospitalized (log-rank, P = 0.062).

CONCLUSIONS

We demonstrated the feasibility and safety of carrying out an outpatient haplo-HSCT, potentially resulting in cost savings and perhaps a higher quality of life.

Optimization of health-care organization and perceived improvement of patient comfort by switching from intra-venous BU four-times-daily infusions to a once-daily administration scheme in adult hematopoietic stem cell recipients

Previous studies have shown an equivalent pharmacokinetic profile between four-times-daily (4QD) and once-daily (QD) administration of intra-venous (IV) BU, without increased toxicity. We assess the impact of a switch in IV BU from a 4QD to a QD schedule, in terms of health-care organization, staff working conditions, quality of care dispensed and perceived patient comfort. Clinicians, nurses and pharmacists from nine allogeneic transplantation units in five European countries were interviewed face to face. Overall perception of QD versus 4QD BU was very positive. Both administration schemes were evaluated to be equally efficaciousZ. QD BU was perceived to be safer and more convenient. Clinicians and nurses perceived that patient comfort was improved, due to fewer complications associated with repeated infusions, and avoiding night infusions associated with stress, anxiety and decreased quality of sleep. Switching from 4QD to QD BU had a significant impact on health-care organization, with a better integration in the overall management and usual timelines in the pharmacies and transplantation units. Time spent to prepare and administer BU was significantly reduced, leading to potential financial savings that merit further assessment and would be of particular interest in the current economic climate.

Tuberculosis and hematopoietic stem cell transplant: Review of a difficult and often underestimated problem

Recipients of solid organ transplants (SOT) and stem cell transplants (SCT) constitute a group of patients at risk for tuberculosis (TB) development. The prevalence of active TB in patients undergoing SOT is higher than in patients undergoing SCT, probably due to the shorter period of immunosuppression in the latter. We reviewed the importance of SCT in individuals with hematological malignancies. Most TB cases occur in transplant patients by reactivation of latent infection after immunosuppression, most often within the first year after transplant, leading to graft loss and in some cases, death. Relevant variables to assess the risk of TB infection in a transplant recipient include the donor’s and recipient’s medical histories, imaging results, microbiology and tuberculin skin test (TST) and interferon-gamma release assays (IGRA). TST is routinely performed in the donor and recipient before transplantation. If TST is > 5 mm in the recipient or > 10 mm in the donor, it is necessary to exclude active TB (pulmonary and renal). Chemoprophylaxis is recommended in TST (+) recipients and in recipients with recent seroconversion, in donors with a history of untreated TB or in contact with an individual with active TB, if radiological images are suspicious and the IGRA is (+). The drug of choice is isoniazid. These topics are herewith reviewed.

Environmental prevention of infection in stem cell transplant recipients: a survey of the Infectious Diseases Working Party of the European Group for Blood and Marrow Transplantation

BACKGROUND

The developments of peripheral blood stem cells in autologous hematopoietic stem cell transplantation (auto-HCT), and of reduced-intensity conditioning (RIC) regimens in allogeneic HCT (allo-HCT), have considerably changed the transplant approach. Prolonged neutropenia combined with severe mucosal damage and organ dysfunction is no longer the rule in the early post-HCT pancytopenic phase. Although strict isolation during pancytopenia was followed by most HCT units in the past, this may not be the current practice.

METHODS

In 2008, a questionnaire was sent out to the 463 European Group for Blood and Marrow Transplantation centers, enquiring about their current environmental protection procedures; 89 (20%) returned the questionnaire.

RESULTS

Most centers housed auto-HCT recipients in high-efficiency particulate air (HEPA)-filtered rooms without (52%) or with laminar air flow (LAF) (29%) after total body irradiation (TBI), whereas HEPA-filtered rooms were used in 53% of auto-HCT conditioned without TBI. During the initial pancytopenic phase after allo-HCT, patients were housed in HEPA/LAF rooms in 50% and 42% of the centers, if a high-dose myeloablative conditioning regimen or a RIC regimen was used, respectively. Surprisingly, 8-24% of the centers reported that no isolation procedures were used in patients colonized or infected with highly transmissible pathogens (i.e., Clostridium difficile, respiratory viruses, and varicella zoster virus).

CONCLUSION

In conclusion, universal recommendations for infected or colonized patients may be poorly known or applied in many HCT units.

Reduced-intensity conditioning allogeneic hematopoietic cell transplantation using oral fludarabine as part of the conditioning regimen

BACKGROUND

In 2003, oral fludarabine was introduced for the treatment of patients with hematologic malignancies as an alternative to its intravenous (i.v.) formulation. In an attempt to simplify the management of patients undergoing reduced intensity allogeneic hematopoietic transplantation, we have incorporated oral fludarabine in the conditioning regimen.

METHODS

We present a non-randomized retrospective analysis of 37 patients conditioned with oral fludarabine compared with 144 patients conditioned with the i.v. formulation. In addition to fludarabine, the conditioning regimens also included melphalan or busulfan depending on the underlying disease. Donors were HLA-matched siblings in 75% of cases and unrelated donors in the remaining 25%.

RESULTS

Eight patients (22%) receiving oral fludarabine were switched to the i.v. route because of gastrointestinal toxicity (three patients), patient preference (two patients) and physician preference (three patients). There were no statistical differences in terms of hospital admission (P=0.16), time to neutrophil engraftment (P=0.35), time to platelet engraftment (P=0.38), acute graft versus host disease rate (P=0.71) and non-relapse mortality at days +30 (P=1.0) and +100 (P=0.43).

DISCUSSION

This preliminary analysis confirms that oral fludarabine can replace its i.v. formulation as part of reduced-intensity conditioning regimens with no deleterious effect on any of the early transplantation outcomes. In addition, oral fludarabine can be more convenient for patients and caregivers, facilitating its implementation.

Outpatient myeloablative allo-SCT: a comprehensive approach yields decreased hospital utilization and low TRM

Historically, myeloablative allogeneic hematopoietic SCT (HSCT) has required prolonged in-patient hospitalization due to the effects of mucosal toxicity and prolonged cytopenias. We explored the safety and feasibility of outpatient management of these patients. A total of 100 consecutive patients underwent a matched-related donor myeloablative allogeneic HSCT for a hematologic malignancy at a single institution. Patients were hospitalized briefly for stem-cell infusion and thereafter only for complications more safely managed in the in-patient setting. The median hospital length of stay from the start of the preparative regimen to day +30 and day +100 post-transplant was 12 and 15 days, respectively. Planned hospital discharge occurred in 79 patients after stem cell infusion. Patients were readmitted to hospital at median of day +7 post transplant, with neutropenic fever being the primary cause for readmission. In total, 18 patients required no in-patient care in the first 100 days. Non-relapse mortality at day 100 and 6 months was 10 and 15%, respectively, for all patients, and 0 and 5%, respectively, for standard risk patients. In summary, outpatient myeloablative allogeneic HSCT with expectant in-patient management can be accomplished safely with low treatment-related morbidity and mortality. Clinical outcomes seem comparable to those reported for traditional in-patient management.

Reduced-intensity conditioning allogeneic stem cell transplantation with donor T-cell depletion using alemtuzumab added to the graft ('Campath in the bag')

Reduced-intensity conditioning (RIC) has allowed the use of allogeneic stem cell transplantation (alloSCT) for haematological malignancies in elderly patients. A major problem of this type of transplantation is the high incidence of persisting chronic graft-versus-host disease (GvHD), leading to increased morbidity and mortality. The inclusion of alemtuzumab added to the graft ('Campath in the bag') for donor T-cell depletion offers an easy procedure to diminish the incidence of GvHD. Good engraftment is observed in most patients, whereas almost no GvHD is observed after transplantation. Most patients become mixed chimeric after transplantation, requiring donor lymphocyte infusion for conversion to full donor chimerism. Although subsequent acute and chronic GvHD is observed in 50-60% of patients, it is responsive to therapy in many patients, resulting in a low incidence of persisting chronic GvHD. AlloSCT with RIC and alemtuzumab-induced T-cell depletion offers a suitable platform for the investigation of novel cellular immunotherapy.

High Incidence of Invasive Aspergillosis Associated with Intestinal Graft-versus-Host Disease following Nonmyeloablative Transplantation

Invasive aspergillosis (IA) remains a major complication following allogeneic hematopoietic stem cell transplant (HSCT). In contrast to conventional HSCT, few investigators have examined risk factors of IA associated with nonmyeloablative (NMA) regimens characterized by outpatient administration, immunosuppression rather than cytoreduction, and short duration of neutropenia posttransplant. We report our results on a cohort of 125 patients treated homogenously who received a 6/6 matched sibling NMA HSCT designed to be performed on an outpatient basis. Conditioning regimen included fludarabine (30 mg/m(2) x 5 days) and cyclophosphamide (300 mg/m(2) x 5 days) followed by reinfusion of a minimum of 4 x 10(6) CD34(+) cells/kg. Acute graft-versus-host disease (aGVHD) prophylaxis consisted of tacrolimus and mycophenolate mofetil (MMF). Overall, 13 patients developed IA (5 proved, 6 probable, 2 possible) 44-791 days (median 229) after NMA HSCT, with a risk of 7% at 1, 11% at 2, and 15% at 3 years. Patients who suffered from IA had poorer overall survival (crude hazard ratio 2.3; 95% confidence interval [CI] 1.0-5.4; P = .045). Intestinal aGVHD or chronic GVHD (cGVHD) was significantly associated with IA at 1 (27% versus 3%, P = .003), 2 (27% versus 8%, P = .01), and 3 years (37% versus 10%, P = .005). The use of daclizumab was also significantly associated with IA at 3 years (47% versus 12%, P = .02). Age, sex, diagnosis, previous autologous transplant, duration of neutropenia, occurrence of cytomegalovirus viremia, duration of steroids or MMF intake, aGVHD, cGVHD, and cumulative number of days spent in hospital were not associated with IA. After multivariate analysis, intestinal GVHD remained the only statistically significant risk factor for IA at 1 (P = .003), 2 (P = .01), and 3 years (P = .005). We conclude that in NMA HSCT, the risk of IA increases over time and is significantly associated with intestinal GVHD. Because there is currently no surrogate in vitro markers of immunocompetence following NMA HSCT, this clinical finding is of particular importance to identify a population at higher risk who should be targeted for antimold prophylaxis.

Outpatient allografting using non-myeloablative conditioning: the Mexican experience

A group of 132 patients with both malignant and nonmalignant conditions was allografted using the 'Mexican' method of non-ablative conditioning. The conditioning was delivered on an outpatient basis and the procedure was planned to be conducted on outpatients in all cases. While 103 patients (78%) were able to complete the procedure totally as outpatients, 29 (22%) were hospitalized because of fever, mucositis or acute graft-versus-host disease. In a multivariate analysis, although differences were not statistically significant, it was found that the patients who were allografted as outpatients had higher levels of hemoglobin (12 versus 11.8 g/dl), higher platelet counts (248 versus 191 x 10(9)/l), lower white blood cell counts (11.7 versus 12.4 x 10(9)/l), higher Karnofsky scale scores (100 versus 90%) and lower creatinine levels (0.9 versus 0.93 mg/dl). A total of 86% of the patients with normal values for these variables could be allografted as outpatients, whereas only 67% of those with abnormal values completed the entire procedure as outpatients. It is concluded that allografting can be accomplished totally on an outpatient basis using the 'Mexican' reduced intensity-conditioning regimen.

Outcomes with Myeloid Malignancies

Reduced-intensity conditioning (RIC) regimens were initially introduced to provide allogeneic stem cell transplantation (HCT), a potentially curative procedure for myeloid malignancies, for patients who were not considered eligible for conventional myeloablative HCT either because of advanced age or excessive comorbidities. A variety of RIC regimens have been studied. The exact definition of RIC remains arbitrary and generally depends upon the perceived toxicity of a given regimen rather than the actual dose of chemotherapy or radiotherapy administered. In several published series, RIC regimens have demonstrated a reduction in non-relapse mortality (NRM), thereby accomplishing the initial goal of expanding the patient population eligible for this potentially curative procedure. Most retrospective studies performed to date have shown a decrease in NRM and an increase in relapse-related mortality with the use of RIC as opposed to conventional myeloablative HCT in myeloid malignancies. This appears to be particularly true for patients who are in relapse at the time of HCT. In contrast, patients who are in remission at time of HCT appear to have a reduction in NRM without a subsequent increase in relapse-related mortality. There is interest in applying RIC to younger patients and to patients with fewer comorbidities as they may have a reduction in NRM without a concomitant increase in relapse. Prospective multicenter studies are needed to define the optimal conditioning regimen, which is likely dependent upon a variety of disease-specific and patient-specific factors.

Reduced-intensity allogeneic stem cell transplantation in adults and children with malignant and nonmalignant diseases: end of the beginning and future challenges

During the last 10 years, multiple studies using reduced-intensity (RI) conditioning followed by allogeneic stem cell transplantation (AlloSCT) have been reported in adult and, less so, pediatric recipients. RI AlloSCT allegedly eradicates malignant cells through a graft-versus-leukemia/graft-versus-tumor effect provided by alloreactive donor T lymphocytes, natural killer cells, or both. Various studies have clearly demonstrated a graft-versus-leukemia/graft-versus-tumor effect in hematologic malignancies and solid tumors. Acute short-term toxicity, including infection and organ decompensation after myeloablative conditioning therapy, can result in a significant incidence of early transplant-related mortality. More importantly, long-term late effects-including growth retardation, infertility, and secondary malignancies-are major complications after myeloablative conditioning therapy, especially in vulnerable children, who are more susceptible to these complications. Recent results comparing RI conditioning with myeloablative conditioning followed by HLA-matched sibling AlloSCT have demonstrated a significant reduction in use of blood products, risk of infections, transplant-related mortality, length of hospitalization, and feasibility of conditioning therapy in outpatient settings. Despite the success of RI AlloSCT, large prospective randomized multicenter studies are necessary to define the appropriate patient population, optimal conditioning regimens and pretransplantation immunosuppression, role of donor lymphocyte infusions, duration of hospitalization, overall survival, cost-benefit ratio, and differences in long-term effects to evaluate the role of RI AlloSCT more fully. We review the recent experience of RI AlloSCT in adults and children with both malignant and nonmalignant diseases and discuss the challenges for the future.

Reduced-Intensity Conditioning Allogeneic Blood Stem Cell Transplantation with Fludarabine and Oral Busulfan with or without Pharmacokinetically Targeted Busulfan Dosing in Patients with Myeloid Leukemia Ineligible for Conventional Conditioning

We prospectively compared outcomes after a fludarabine (Flu) plus oral busulfan (Bu)-containing reduced-intensity conditioning regimen (150 mg/m2 Flu and 10 mg/kg oral Bu), with (n = 32; Flu- T Bu group) or without (n = 30; Flu-Bu group) therapeutic dose monitoring and dose adjustment of Bu. All patients received peripheral blood stem cells from a genoidentical sibling, and study cohorts had similar patient characteristics. Dose adjustments of Bu were required in 20 (63%) patients in the Flu- T Bu group (median final dose, 8.89 mg/kg; range, 6.3-13.34 mg/kg). Donor T-cell and granulocyte engraftments were similar, and early conditioning-related toxicities were mild and similar in both study groups. With a median follow-up of 45 months (51 months in the 37 survivors), posttransplantation outcomes did not differ between cohorts. The strongest predictor of 2-year overall survival and leukemia-free survival was the presence of chronic graft-versus-host disease (77% versus 34% for overall survival and 74% versus 34% for leukemia-free survival; P < .001 for both outcomes). In conclusion, therapeutic dose monitoring of oral Bu in a reduced-intensity conditioning setting does not seem to affect outcome, although further studies may identify very-high-risk patients who benefit from this strategy.