Use of heparin versus lepirudin flushes to prevent withdrawal occlusion of central venous access devices.

STUDY OBJECTIVE: To determine whether lepirudin flushes are more effective than heparinized saline in preventing withdrawal occlusion of central venous access devices. DESIGN: Randomized, double-blind clinical trial. SETTING: Research institution-tertiary referral center. PATIENTS: Forty-nine adults undergoing bone marrow transplantation for hematologic malignancies or metastatic solid tumors. INTERVENTION: Twenty-four patients received heparin and 25 received lepirudin flushes. The heparin dose was 3 ml of porcine heparin 100 U/ml (300 U) per catheter lumen at least once/day; the lepirudin dose was 3 ml of lepirudin 100 microg/ml (300 microg) per catheter lumen at least once/day. After 3-4 weeks, all 49 patients received the heparin flushes. MEASUREMENTS AND MAIN RESULTS: Efficacy was assessed by the frequency with which the patients were treated with alteplase instillations for withdrawal occlusion of their central venous access devices during the first 4 months of catheterization. Three (12.5%) patients treated with heparin alone and five (20%) treated initially with lepirudin required alteplase instillations for an estimated relative risk with lepirudin versus heparin of 1.6 (95% confidence interval [CI] 0.40-13.86, p=0.70). CONCLUSION: Lepirudin was not more effective than heparin, which may have been related to the conservative dose of lepirudin administered. However, higher lepirudin doses are likely to incur an unacceptable risk of systemic anticoagulation.

Efficacy of reduced-intensity allogeneic stem cell transplantation in chemotherapy-refractory non-hodgkin lymphoma.

Chemotherapy sensitivity has been identified as an important prognostic factor in reduced-intensity allogeneic stem cell transplantation (RIST) for non-Hodgkin lymphoma (NHL). However, the effect of uniform salvage chemotherapy before RIST has not been studied prospectively. We examined whether the response to prospectively administered uniform salvage therapy (etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and fludarabine) influenced the subsequent outcome of RIST in 28 patients with relapsed or refractory NHL. After RIST, overall survival (OS) at 36 months is 49%, whereas event-free survival (EFS) is 32%. In Cox model analyses, the response to chemotherapy was the best predictor of OS (P = .0006) and EFS (P = .0006) after RIST. Differentiating stable disease from progressive disease after salvage chemotherapy strengthened the association with survival. Among chemotherapy-sensitive patients, the median OS and EFS have not been reached. In patients with stable disease, OS and EFS at 24 months are 50% and 25%, respectively. In contrast, only 1 patient with progressive disease during salvage therapy survived longer than 12 months. These prospective data confirm the favorable prognosis for chemotherapy-sensitive NHL after RIST and suggest that chemotherapy resistance is not an absolute contraindication to RIST for NHL patients with stable disease during salvage therapy.

Age-dependent incidence, time course, and consequences of thymic renewal in adults.

Homeostatic regulation of T cells involves an ongoing balance of new T cell generation, peripheral expansion, and turnover. The recovery of T cells when this balance is disrupted provides insight into the mechanisms that govern homeostasis. In a long-term, single cohort study, we assessed the role of thymic function after autologous transplant in adults, correlating serial computed tomography imaging of thymic size with concurrent measurements of peripheral CD4(+) T cell populations. We established the age-dependent incidence, time course, and duration of thymic enlargement in adults and demonstrated that these changes were correlated with peripheral recovery of naive CD45RA(+)CD62L(+) and signal-joint TCR rearrangement excision circle-bearing CD4(+) populations with broad TCR diversity. Furthermore, we demonstrated that renewed thymopoiesis was critical for the restoration of peripheral CD4(+) T cell populations. This recovery encompassed the recovery of normal CD4(+) T cell numbers, a low ratio of effector to central memory cells, and a broad repertoire of TCR Vbeta diversity among these memory cells. These data define the timeline and consequences of renewal of adult thymopoietic activity at levels able to quantitatively restore peripheral T cell populations. They further suggest that structural thymic regrowth serves as a basis for the regeneration of peripheral T cell populations.

Targeted pretransplant host lymphocyte depletion prior to T-cell depleted reduced-intensity allogeneic stem cell transplantation.

Mixed chimaerism and graft rejection are higher after reduced-intensity allogeneic stem cell transplantation (RIST) with T-cell depleted (TCD) allografts. As host immune status before RIST affects engraftment, we hypothesized that targeted depletion of host lymphocytes prior to RIST would abrogate graft rejection and promote donor chimaerism. Lymphocyte-depleting chemotherapy was administered at conventional doses to subjects prior to RIST with the intent of decreasing CD4(+) counts to <0.05 x 10(9)cells/l. Subjects (n = 18) then received reduced-intensity conditioning followed by ex vivo TCD human leucocyte antigen-matched sibling allografts. All evaluable patients (n = 17) were engrafted; there were no late graft failures. At day +28 post-RIST, 12 patients showed complete donor chimaerism. Mixed chimaerism in the remaining five patients was associated with higher numbers of circulating host CD3(+) cells (P = 0.0032) after lymphocyte-depleting chemotherapy and was preferentially observed in T lymphoid rather than myeloid cells. Full donor chimaerism was achieved in all patients after planned donor lymphocyte infusions. These data reflect the importance of host immune status prior to RIST and suggest that targeted host lymphocyte depletion facilitates the engraftment of TCD allografts. Targeted lymphocyte depletion may permit an individualized approach to conditioning based on host immune status prior to RIST.

Allogeneic lymphocytes induce tumor regression of advanced metastatic breast cancer.

PURPOSE: Allogeneic T lymphocytes can induce regression of metastatic breast cancer through an immune-mediated graft-versus-tumor (GVT) effect in murine models. To determine if a clinical GVT effect exists against metastatic breast cancer, allogeneic lymphocytes were used as adoptive cellular therapy after a reduced-intensity chemotherapy conditioning regimen and allogeneic hematopoietic stem-cell transplantation (HSCT) from human leukocyte antigen-matched siblings. PATIENTS AND METHODS: Sixteen patients with metastatic breast cancer that had progressed after treatment with anthracyclines, taxanes, hormonal agents, and trastuzumab, received allogeneic HSCT. The reduced-intensity transplant conditioning regimen consisted of cyclophosphamide and fludarabine. To distinguish an immunological GVT effect from any antitumor effect of cytotoxic chemotherapy in the transplant-conditioning regimen, allogeneic T lymphocytes were removed from the stem-cell graft and were subsequently administered late postallogeneic HSCT. Allogeneic lymphocytes containing 1 x 10(6), 5 x 10(6), and 10 x 10(6) CD3(+) cells/kg were infused on days +42, +70, and +98 post-allogeneic HSCT, respectively. RESULTS: Objective tumor regressions occurred after day +28 post-allogeneic HSCT in six patients and were attributed to allogeneic lymphocyte infusions. Two of these responding patients had disease progression post-allogeneic HSCT before subsequent tumor regression. Tumor regressions occurred concomitantly with the establishment of complete donor T-lymphoid engraftment, were associated with the development of graft-versus-host disease (GVHD), and were abrogated by subsequent systemic immunosuppression for GVHD. CONCLUSION: Allogeneic lymphocytes can induce regression of advanced metastatic breast cancer. These results indicate that an immunological GVT effect from allogeneic lymphocytes exists against metastatic breast cancer and provide rationale for further development of allogeneic cellular therapy for this largely incurable disease.

Human CTLs to wild-type and enhanced epitopes of a novel prostate and breast tumor-associated protein, TARP, lyse human breast cancer cells.

Vaccine therapy for prostate and breast cancer may have potential for treating these major causes of death in males and females, respectively. Critical to the development of tumor-specific vaccines is finding and characterizing novel antigens to be recognized by CD8(+) T cells. To define new CD8(+) T-cell tumor antigens, we determined two wild-type HLA-A2 epitopes from a recently found tumor-associated protein, TARP (T-cell receptor gamma alternate reading frame protein), expressed in prostate and breast cancer cells. We were also able to engineer epitope-enhanced peptides by sequence modifications. Both wild-type and enhanced epitopes induced peptide-specific CD8(+) T-cell responses in A2K(b) transgenic mice. In vitro restimulation of human CD8(+) T cells from a prostate cancer patient resulted in CD8(+) T cells reactive to the peptide epitopes that could lyse HLA-A2(+) human breast cancer cells (MCF-7) expressing TARP. Epitope-specific human CD8(+) T cells were also enumerated in patients' peripheral blood by tetramer staining. Our data suggest that HLA-A2-binding TARP epitopes and enhanced epitopes discovered in this study could be incorporated into a potential vaccine for both breast and prostate cancer.

Clinical "cytokine storm" as revealed by monocyte intracellular flow cytometry: correlation of tumor necrosis factor alpha with severe gut graft-versus-host disease.

BACKGROUND & AIMS: Gut graft-versus-host disease (GVHD) contributes significantly to lethality after allogeneic hematopoietic stem-cell transplantation (HSCT). In murine models, macrophage secretion of interleukin 1alpha (IL-1alpha) and tumor necrosis factor alpha (TNF-alpha) contributes to gut GVHD pathogenesis. To help characterize whether human gut GVHD has similar biological characteristics, monocyte IL-1alpha and TNF-alpha production were evaluated after HSCT. METHODS: Patients with refractory hematologic malignancy (n = 17) underwent reduced-intensity conditioning, HLA-matched sibling HSCT, and cyclosporine A GVHD prophylaxis. After HSCT, monocyte IL-1alpha and TNF-alpha levels were measured using intracellular flow cytometry (IC-FCM), and results were correlated with clinical GVHD. RESULTS: Incidences of acute GVHD were none (n = 3), grades I-II (n = 9), or grades III-IV (n = 5; each case with stage 2-3 gut GVHD). Posttransplantation monocyte IL-1alpha production (percentage of CD14(+)IL-1(+) cells) increased significantly from 8.7% +/- 3.7% (week 2) to 40.3% +/- 7.3% (week 4; P = 0.0065) and was not associated with GVHD severity (P = 1.00). Conversely, increases in monocyte TNF-alpha were quantitatively reduced and temporally delayed, from 0.6% +/- 0.2% (week 2) to 3.6% +/- 1.4% (week 6; P = 0.076). Most importantly, elevation of monocyte TNF-alpha level correlated with increased gut GVHD severity (P = 0.0041); increases in monocyte TNF-alpha levels typically preceded the onset of gut GVHD symptoms. CONCLUSIONS: Human gut GVHD after reduced-intensity allogeneic HSCT is associated with monocyte cytokine secretion initially involving IL-1alpha, followed by TNF-alpha. Serial measurement of monocyte cytokines, in particular, TNF-alpha, by IC-FCM may represent a noninvasive method for GVHD monitoring, potentially allowing the identification of patients appropriate for early-intervention strategies.

Establishment of early donor engraftment after reduced-intensity allogeneic hematopoietic stem cell transplantation to potentiate the graft-versus-lymphoma effect against refractory lymphomas.

Reduced-intensity allogeneic hematopoietic stem cell transplantation (alloHSCT), which typically results in mixed chimerism initially after transplantation, has had limited efficacy in chemotherapy-refractory lymphomas. We hypothesized that the rapid establishment of complete donor chimerism would potentiate a graft-versus-lymphoma effect. Fifteen patients with chemotherapy-refractory lymphoma initially received induction with a conventional chemotherapy regimen (etoposide, prednisone, vincristine, cyclophosphamide, adriamycin, fludarabine [EPOCH-F]) to deplete host T cells and provide disease control prior to alloHSCT. Patients then received conditioning with fludarabine and cyclophosphamide followed by alloHSCT from HLA-matched siblings. Graft-versus-host disease prophylaxis consisted of cyclosporine alone. EPOCH-F resulted in 73% of patients having partial responses or stable disease. EPOCH-F depleted host CD4(+) T cells from a median of 235 cells/microL to 56 cells/microL. Fourteen patients underwent alloHSCT, and all had >95% donor engraftment by day 14 after transplantation. The incidence of Grade II to III acute graft-versus-host disease was 71%. There were two therapy-related deaths. There were 8 partial responses and 3 complete responses (CRs) at day 28. Five additional CRs were observed at day 100 without withdrawal of cyclosporine or donor lymphocyte infusion. The rate of CRs for all 15 patients was 60%. The 1-year progression-free survival rate from time of study entry is 67% with only 1 relapse among 9 CRs. At a median potential follow-up of 28 months, the overall survival rate is 53%. These data demonstrate that a potent and durable graft-versus-lymphoma effect can occur against chemotherapy-refractory lymphomas and suggest that this effect may be associated with rapid, complete donor chimerism after reduced-intensity alloHSCT.

Radioimmunotherapy of interleukin-2R - expressing adult T-cell leukemia with yttrium-90-labeled anti-tac

Adult T-cell leukemia (ATL) is a malignancy of mature lumphocytes caused by the retrovirus human T-cell lymphotropic virus-I. It is an aggressive leukemia with a median survival time of 9 months: no chemotherapy regimen appears successful inducing long-term disease-free survival. The scientific basis of the present study is the ATL cells express high-affinity interleukin-2 receptors identified by the anti-Tac monoclonal antibody, whereas normal resting cells do not. To exploit this differnce, we administered anti-Tac armed with Yttrium-90 (Y) to 18 patients with ATL initially (first 9 patients) in a phase I dose-escalation trial and subsequently (second group of 9 patients) in a phase II trial involving a uniform 10-mCi dose of Y-labeled anti-Tac. Patients undergoing a remission were permitted to receive up to eight additional doses. At the 5-to 15-mCi doses used, 9 of 16 evaluable patients responded to Y anti-Tac with a partial (7 patients) or complete (2 patients) remission. The responses observed represent improved efficacy in terms of length of remission when compared with previous results with unmodified anti-Tac. Clinically meaningful (> grade 3) toxicity was largely limited to the hematopoietic system. In conclusion, radioimmunotherapy with Y anti-Tac directed toward the IL-2R expressed on ATL cells may provide a useful approach for treatment of this aggressive malignancy.(AU)