Compared to older adults, the role of NM-HCT to cure pediatric malignancies is not well-established and has typically been reserved for high-risk patients (pts). We conducted a retrospective multi-center analysis of all pts who were <22 yrs old with hematological malignancies treated on protocol to determine factors associated with outcome after NM-HCT. Between Jan 2001-July 2008, 26 pts with a median age of 17.9 (5.1-21.9) yrs were treated for ALL (CR1,n=1;CR2,n=3;CR3,n=5), AML (CR2,n=5; CR4,n=1; PR, n=1), Hodgkin lymphoma (CR1,n=1; CR3, n=2; PR,n=2;Ref,n=1), MDS (n=2), or NHL (CR3, n=1; Rel, n=1). NM-HCT was chosen for concern of increased regimen-related toxicity due to comorbidities alone (n=11) or prior myeloablative auto or allo-HCT with or without comorbidities (n=15). Median HCT-CI score was 2 (range, 0-5) (n=25). Pts were conditioned with either 2 Gy TBI (n=3), or Flu 90 mg/m2+2 Gy TBI (n=23). Pts were given peripheral blood stem cells (PBSC) (n=24) or marrow (n=2) grafts from HLA-identical sibs or unrelated donors matched for 10/10 (n=15), 9/10 (n=5), or 8/10 (n=1) alleles. Post-grafting immunosuppression consisted of either CSP/MMF (n=22), tacrolimus/MMF (n=1), or tacrolimus/MMF/sirolimus (n=3). Donor CD3 chimerism was documented in 25 pts at day 28, but was not evaluated in 1 pt who died on day 23 after achieving normal granulocyte counts. Secondary graft rejection occurred at day 56 in 1 pt with MDS given marrow, who subsequently achieved full donor chimerism after a second myeloablative HCT with PBSC. Of 24 evaluable pts, 20 converted to full donor CD3 chimerism (95-100%) while 4 remained with mixed CD3 chimerism (15-93%). Twenty pts developed acute GVHD (grade II=17; III=3) at a median of 34 (range, 9-56) days after HCT. The cumulative incidence of chronic GVHD was 51% at 2 yrs. Causes of death included disease progression/relapse (n=13), complications of GVHD (n=4), or sepsis/pulmonary complications (n=2). The 2 year overall survival (OS), progression-free survival, relapse, and non-relapse mortality were 49%, 28%, 58% and 14%, respectively. On univariate analysis, pts with HCT-CI ≥3 had worse OS (p=0.008). In this small cohort, there was no survival benefit for pts with myeloid vs lymphoid malignancies or disease status at HCT. In conclusion, NM-HCT remains an important curative option for a subset of high-risk pediatric pts who would otherwise not qualify for high-dose therapy, with relapse being the highest contributor to overall mortality.

Conventional allografting produces considerable regimen-related toxicities that generally limit this treatment to patients younger than 55 years and in otherwise good medical condition. T cell-mediated graft-versus-tumor (GVT) effects are known to play an important role in the elimination of malignant disease after allotransplants. A minimally myelosuppressive regimen that relies on immunosuppression for allogeneic engraftment was developed to reduce toxicities while optimizing GVT effects. Pre-transplant total-body irradiation (200 cGy) followed by post-transplant immunosuppression with cyclosporine (CSP) and mycophenolate mofetil (MMF) permitted human leukocyte antigen (HLA)-matched sibling donor hematopoietic cell engraftment in 82% of patients (n = 55) without prior high-dose therapy. The addition of fludarabine (90 mg/m(2)) facilitated engraftment in all 28 subsequent patients. Overall, fatal progression of underlying disease occurred in 20% of patients after transplant. Non-relapse mortality occurred in 11% of patients. Toxicities were low. Grade 2-4 acute graft-versus-host disease (GVHD) associated with primary engraftment developed in 47% of patients, and was readily controlled in all but two patients. Donor lymphocyte infusions (DLI) were not very effective at converting a low degree of mixed donor/host chimerism to full donor chimerism; however, the addition of fludarabine reduced the need for DLI. With a median follow-up of 244 days, 68% of patients were alive, with 42% of patients in complete remission, including molecular remissions. Remissions occurred gradually over periods of weeks to a year. If long-term efficacy is demonstrated, such a strategy would expand treatment options for patients who would otherwise be excluded from conventional allografting.

The development of nonmyeloablative allogeneic hematopoietic stem cell transplantation (HSCT) from the preclinical studies to the clinic has permitted the treatment of a larger number of patients who previously had not been candidates for the standard approach with myeloablation. This includes older patients and those patients who had contraindications to intensive cytotoxic regimens. Regimen-related toxicities (RRT) after myeloablation result in prolonged periods of hospitalization and the development of significant morbidity and potential mortality including veno-occlusive disease and idiopathic interstitial pneumonitis. Severe RRT can generally be avoided after nonmyeloablative conditioning. A graft-versus-leukemia reaction is critical to the eradication of many hematological malignancies after transplantation and has been shown to be effective in those patients who have been infused with lymphocytes from the donor (DLI) after relapse.

The efficacy and safety of ebastine 20 mg once daily given with and without food were compared in patients ages 12 to 70 years with seasonal allergic rhinitis (SAR) caused by mountain cedar allergen. This double‐blind, placebo‐controlled study was conducted at six centers in Texas. Efficacy and safety analyses were performed on the intent‐to‐treat population, which comprised 652 patients; 540 patients completed the study. Following 2 weeks' treatment, no significant differences (p ≥ 0.91) were found between the ebastine with and without food groups in the percentage change from baseline of daily “reflective” total rhinitis symptom scores (i.e., patients' assessment of severity over the previous 12 h), but both ebastine groups exhibited significantly greater reductions versus patients receiving placebo (p < 0.0001). There were also no significant differences in the percentages ofpatients experiencing adverse events between the ebastine with and without food groups. Mean steady‐state plasma concentrations of ebastine and its active metabolite carebastine were, respectively, 5.5% (ns) and 15.1% (p < 0.05) higher when ebastine was given with food versus its administration without food. Overall, these results indicate that in clinical practice, ebastine does not need to be administered with reference to food.

Conventional approaches to allogeneic stem cell transplantation have used toxic high-dose conditioning therapy to achieve allogeneic engraftment and control of underlying disease. For engraftment purposes, preclinical studies and clinical observations have shown that conditioning regimens can be markedly reduced in intensity, resulting in reduced treatment toxicities. Preclinical canine studies demonstrated that the use of potent pre- and postgrafting immunosuppression allows for reduction in conditioning regimens while facilitating development of stable mixed chimerism. If attenuated conditioning regimens can be successfully translated to human stem cell transplantation, an improved safety profile will allow potentially curative treatment to a more representative patient profile not currently offered such therapy. Mixed chimerism could prove curative of disease phenotype of various nonmalignant disturbances of the hematopoietic and immune systems. For patients with hematopoietic malignancy, spontaneous conversion to full donor hematopoeisis after stem cell transplant may prove curative by virtue of graft versus host reactions directed against the malignancy, however infusion of additional donor lymphocytes may be needed to treat persistent disease.

Stable mixed donor/host hematopoietic chimerism can be uniformly established in dogs conditioned with 200 cGy TBI before dog leukocyte antigen (DLA)-identical marrow transplantation and immunosuppressed with a short course of mycophenolate mofetil (MMF) and cyclosporine (CSP) after the transplantation. A further decrease in the TBI dose to 100 cGy or the elimination of MMF in this model results in graft rejection. Here we asked whetherthe addition of G-CSF-mobilized peripheral blood mononuclear cells (G-PBMC) to marrow grafts would enhance donor engraftment in dogs conditioned with 100 cGy TBI and given postgrafting immunosuppression with CSP alone. Using this model, 7 of 9 dogs given only marrow cells rejected their grafts within 8 to 17 weeks after transplantation. In contrast, the addition of unmodified G-PBMC to marrow grafts resulted in stable mixed donor/host chimerism in 5 of 8 dogs studied (P = .06). However, addition of the CD3-depleted fraction of G-PBMC, which contained both CD34 cells and CD14 cells, resulted in engraftment in only 1 of 7 recipients. We conclude that adding G-PBMC to marrow grafts replaced the requirement of MMF and 100 cGy of TBI, and that CD3 cells were required to facilitate engraftment of marrow cells in DLA-identical recipients, whereas the additional CD34 cells present in G-PBMC were not sufficient for this effect.

A retrospective analysis of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood mononuclear cell (G-PBMC) products harvested from healthy donors indicates significant variability in both the absolute number and relative proportion of CD34, CD3, and CD14 cells obtained. This report examined whether variations in the cellular composition of G-PBMC products correlated with clinical outcomes after myeloablative allogeneic transplantation. The numbers of CD34, CD3, and CD14 cells infused into 181 human leukocyte antigen (HLA)-identical sibling recipients were analyzed with respect to tempo of engraftment, acute graft-versus-host-disease (GVHD), clinical extensive chronic GVHD, overall survival, and disease relapse. Neither acute GVHD, overall survival, nor disease relapse was statistically significantly associated with CD34, CD3, or CD14 cell doses or the CD14 to CD3 ratio. CD3 and CD14 cell doses and CD14 to CD3 ratios did not correlate with the tempo of neutrophil and platelet engraftment. However, increasing CD34 cell numbers were significantly associated with accelerated neutrophil (P =.03) and platelet (P =.01) engraftment. Higher doses of CD34 cells (> 8.0 x 10(6)/kg) were also associated with a significantly increased hazard of clinical extensive chronic GVHD (HR = 2.3, 95% confidence interval [CI] 1.4-3.7, P =.001), but neither CD3 nor CD14 doses were statistically significantly associated with chronic GVHD. It was concluded that CD34 cell dose in G-PBMC grafts appears to affect both the engraftment kinetics and the development of clinical extensive chronic GVHD in HLA-identical sibling recipients but without a demonstrable impact on survival, relapse, and acute GVHD. Given the morbidity associated with extensive chronic GVHD, efforts to further accelerate engraftment in HLA-matched sibling transplants by increasing CD34 cell number in G-PBMC products may be counterproductive.

Stable mixed donor/host hematopoietic chimerism can be accomplished in dog leukocyte antigen (DLA)-identical littermate dogs given sublethal (200 cGy) total-body irradiation (TBI) before and immunosuppression with mycophenolate mofetil (MMF) and cyclosporine (CSP) after transplant (Blood 89:3048, 1997). Studies were based on the hypothesis that drugs that prevent graft-versus-host disease (GVHD) after transplant also suppress host-versus-graft (HVG) reactions and thereby enhance engraftment. Here, we asked whether pretransplant TBI provided marrow space for the graft to home or caused host immunosuppression. To address the questions, recipients were given pretransplant irradiation to cervical, thoracic, and abdominal lymph nodes (except pelvis), DLA-identical littermate marrow grafts, and MMF/CSP posttransplant. Six dogs that received 450 cGy irradiation showed initial engraftment. Two rejected their grafts after 8 and 18 weeks, 1 died with GVHD and engraftment, and 3 are alive as mixed chimeras after 57 to 97 weeks. Four dogs given 200 cGy irradiation also showed initial engraftment, but rejected their grafts after 10 to 18 weeks. Mixed chimerism was present in nonirradiated marrow and lymph node spaces and involved granulocytes, T cells, and monocytes. While other explanations are possible, results seem consistent with the hypothesis that pretransplant radiation provides host immunosuppression, and grafts can create their own marrow space. These data set the stage for the development of novel transplant regimens that substitute immunosuppressive for cytotoxic agents.

Abstract: This paper describes the development of nonmyeloablative marrow transplant programs that have little toxicity in a canine model and their translation to patients with malignant and nonmalignant hematological diseases.

Stable mixed chimerism can be established in dogs given a sublethal dose of 200 cGy total body irradiation (TBI) before and immunosuppression with mycophenolate mofetil (MMF) and cyclosporine (CSP) for 28 and 35 days, respectively, after dog leukocyte antigen-identical marrow transplantation. Most likely, the role of pretransplant TBI was to provide host immunosuppression, since stable mixed chimerism was also achieved in MMF/CSP-treated dogs when 450 cGy irradiation, targeted to cervical, thoracic, and upper abdominal lymph nodes, was substituted for TBI. When TBI was reduced from 200 to 100 cGy, all grafts were rejected within 3 to 12 weeks. Here, we asked whether stable engraftment after 100 cGy TBI could be accomplished by first reducing the intensity of host immune responsiveness with help of the fusion peptide CTLA4Ig, which blocks T-cell costimulation through the B7-CD28 signal pathway. Accordingly, recipient T cells were activated with intravenous (IV) injections of 10(6) donor peripheral blood mononuclear cells (PBMC)/kg per day on days -7 to -1 before 100 cGy TBI, with concurrent administration of CTLA4Ig 4 mg/kg/d IV. All 7 dogs so treated showed initial mixed chimerism. Two rejected their allografts after 8 and 20 weeks, respectively, and survived with autologous marrow recovery; 1 mixed chimera was unevaluable because of death at 3 weeks from intussusception; and 4 showed persisting mixed chimerism, including unirradiated marrow and lymph node spaces, for now more than 46 to 70 weeks after transplant. Data support the hypothesis that stable marrow allografts can be established by combining nonmyeloablative pretransplant host immunosuppression with posttransplant host and donor cell immunosuppression using MMF/CSP.

Allogeneic transplantation (allo) of patients with multiple myeloma is a controversial treatment due to high transplant related mortality (TRM) with myeloablative conditioning before the transplant. However, using reduced intensity conditioning (RIC) and previous autologous transplantation (auto) has dramatically reduced TRM. This, in combination with a lower relapse/progression rate, has in two out of six prospective studies resulted in prolongation of both progression free survival (PFS) and overall survival (OS) as compared to auto. No prospective study has proven auto – single or tandem – to be better than the auto/RICallo modality. The rapid development of relatively effective drugs in multiple myeloma has made most centers reluctant to use upfront RICallo. Considering the initial TRM of 12–16% with this treatment, it is now mainly used after progression-relapse following auto. New studies including more effective GVHD prevention and combination of allo with new drugs in the conditioning and as maintenance therapy are ongoing or in planning. Until clear advantageous results have been shown it seems reasonable to use the auto/RICallo procedure mainly in relapsed patients or upfront in patients with poor prognostic parameters such as del17p, del8p or gain 1q. The prospects for long-term survival or perhaps cure for a fraction of patients seem highest following some kind of allo.