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Biomedical subjects

D L Porter

Publications and source records attributed to D L Porter.

At least 19 recordsLinked to original sources
PubMed2006

Prognostic value of FDG-PET scan imaging in lymphoma patients undergoing autologous stem cell transplantation.

We conducted a retrospective analysis of 50 lymphoma patients (Hodgkin's disease and non-Hodgkin's lymphoma) who had an 18F-fluoro-deoxyglucose positron emission tomography (FDG-PET) scan after at least two cycles of salvage chemotherapy and before autologous stem cell transplantation (ASCT) at our institution. The patients were categorized into FDG-PET negative (N = 32) and positive (N = 18) groups. The median follow-up after ASCT was 19 months (range: 3-59). In the FDG-PET-negative group, the median progression-free survival (PFS) was 19 months (range: 2-59) with 15 (54%) patients without progression at 12 months after ASCT. The median overall survival (OS) for this group was not reached. In the FDG-PET-positive group, the median PFS was 5 months (range: 1-19) with only one (7%) patient without progression at 12 months after ASCT. The median OS was 19 months (range: 1-34). In the FDG-PET-negative group, chemotherapy-resistant patients by CT-based criteria had a comparable outcome to those with chemotherapy-sensitive disease. A positive FDG-PET scan after salvage chemotherapy and prior ASCT indicates an extremely poor chance of durable response after ASCT.

Adult↗
PubMed2005

Intensive graft-versus-host disease prophylaxis is required after unrelated-donor nonmyeloablative stem cell transplantation.

Nonmyeloablative stem cell transplantation (NST) harnesses the graft-versus-tumor effect while minimizing regimen-related toxicity, and can result in donor chimerism and remission. Acute graft-versus-host disease (GVHD) and infections are major complications after sibling NST. Toxicity of unrelated-donor (UD) NST and the most appropriate GVHD prophylaxis in this setting remain poorly defined. We describe 25 patients who received UD-NST conditioned with fludarabine and cyclophosphamide. The first six patients received cyclosporine (Cs) and mycophenolate mofetil (MMF) (n=5) or methotrexate (MTX) (n=1) as GVHD prophylaxis (group 1) and all developed grade III-IV acute GVHD. The next 19 patients received the same conditioning regimen with the addition of alemtuzumab, and all received Cs/MTX post-transplant. Engraftment and donor chimerism were achieved in all but one evaluable patient. In all, 15 patients died: five of six deaths in group 1 were attributable to acute GVHD, while deaths in group 2 were due to infection or progressive disease (P=0.05). The combination of Cs/MMF is inadequate GVHD prophylaxis for UD-NST. The use of Cs, MTX, and alemtuzumab eliminated severe acute GVHD; its impact on response merits further study.

Adult↗
PubMed2005

T-cell reconstitution and expansion after hematopoietic stem cell transplantation: 'T' it up!

Adoptive immunotherapy is the isolation and infusion of antigen-specific or nonspecific lymphocytes. Adoptive therapy with T cells may have a role in replacing, repairing, or enhancing immune function damaged by cytotoxic therapies, and rapid lymphocyte recovery may improve outcome after autologous and allogeneic stem cell transplantation (SCT). Recently, a plethora of information on the basic mechanisms of T-cell biology and regulation of cellular immune responses has emerged, permitting the development of new forms of adoptive cell therapy. Efficient ex vivo culture method for T-cell subsets affords the possibility of adoptive transfer of T cells engineered with enhanced capacity for central memory, effector cytotoxicity, Th1, Th2, veto cell, and T regulatory functions. Studies show that homeostatic T-cell proliferation is important for effective adoptive immunotherapy and pretreatment with chemotherapy may enhance the effects of infused T cells. Replicative senescence, in part due to telomere erosion, likely limits successful adoptive immunotherapy, though it may be possible to maintain T-cell pools by enforced expression of telomerase. Clinical trials now demonstrate that it is possible to enhance immune reconstitution after SCT with cytokines or infusions of ex vivo costimulated expanded T cells. These data all support the premise that adoptive therapy can accelerate reconstitution of cellular immunity with enhanced antitumor effects following SCT.

Adoptive Transfer↗
PubMed2005

Long-term event-free survivors after high-dose therapy and autologous stem-cell transplantation for low-grade follicular lymphoma.

Although follicular lymphoma (FL) is generally responsive to conventional-dose chemotherapy, improved survival in patients with this disease has been difficult to demonstrate. High-dose chemo/radiotherapy followed by autologous stem-cell transplantation (ASCT) can improve response rates, although its effects on survival remain controversial. Between 1990 and 2003, we transplanted 49 patients with low-grade FL at our institution. Twenty-two patients (45%) had undergone histologic transformation at the time of ASCT. In all, 44 patients (90%) had relapsed disease and five patients (10%) were resistant to chemotherapy at the time of transplantation. After ASCT, 30 patients (61%) were in complete remission (CR). The median overall survival (OS) has not been reached, while the median event-free survival (EFS) is 2.4 years. At a median follow-up of 5.5 years (longest 12.4 years), a plateau has been reached with 56% of patients remaining alive, and 35% event-free. ASCT was well tolerated except for two (4%) treatment-related deaths. In multivariable analysis, CR after ASCT and age less than 60 years are the best predictors of EFS and OS. ASCT is thus a safe therapeutic approach in FL, resulting in long-term EFS and OS for some patients, even with transformed disease.

Adult↗
PubMed2003

Post-transplant lymphoproliferative disorder: a review.

Post-transplant lymphoproliferative disorder (PTLD) represents a spectrum of Epstein-Barr virus-related (EBV) clinical diseases, from a benign mononucleosis-like illness to a fulminant non-Hodgkin's lymphoma. In the setting of hematopoietic stem cell transplantation, PTLD is an often-fatal complication occurring relatively early after transplant. Risk factors for the development of PTLD are well established, and include HLA-mismatching, T-cell depletion, and the use of antilymphocyte antibodies as conditioning or treatment of graft-versus-host disease. Early recognition of PTLD is particularly important in the SCT setting, because PTLD in these patients tends to be rapidly progressive. Familiarity with the clinical features of PTLD and a heightened level of suspicion are critical for making the diagnosis. Surveillance techniques with EBV antibody titers and/or polymerase chain reaction (PCR) may have a role in some high-risk settings. Immune-based therapies such as monoclonal anti-B-cell antibodies, interferon-alpha, and EBV-specific donor T cells, either as treatment for PTLD or as prophylaxis in high-risk patients, represent promising new directions in the treatment of this disease.

Histocompatibility Testing↗
PubMed2003

'GVHD': graft-versus-host disease or graft-versus-Hodgkin's disease? An old acronym with new meaning.

The majority of patients with relapsed or refractory Hodgkin's lymphoma (HL) will not be cured with standard therapy. Relapse rates remain high even after autologous stem cell transplantation (SCT), particularly for patients with high-risk disease. Allogeneic SCT offers several potential advantages for patients with HL. It is feasible when autologous stem cells are not available and stem cell grafts will be tumor free. Perhaps a more important advantage is the potential to generate a graft-versus-Hodgkin's lymphoma (GVHL) effect. Unfortunately, although allogeneic SCT may cure some HL patients, treatment-related mortality has been unusually high, and superior survival, when compared to autologous SCT, has not been demonstrated. Nonmyeloablative conditioning and allogeneic SCT may induce a direct GVHL reaction with less conditioning regimen-related toxicity and ultimately may have the potential to improve cure rates and survival for advanced HL patients.

Graft vs Host Disease↗
PubMed2002

Nonmyeloablative allogeneic stem cell transplantation for refractory Hodgkin's lymphoma complicated by interleukin-2 responsive progressive multifocal leukoencephalopathy.

Nonmyeloablative allogeneic stem cell transplantation (NMASCT) can be used to exploit the graft-versus-tumor (GVT) potential of allogeneic donor cells in the setting of reduced conditioning regimen toxicity. This approach is particularly attractive for patients who have received extensive prior therapy and are poor candidates for traditional allogeneic stem cell transplantation. However, toxicity in heavily pretreated patients remains uncertain. Additional immunosuppression in already immunocompromised patients may result in unexpected toxicity. We report a case of probable progressive multifocal leukoencephalopathy (PML) responsive to interleukin-2 (IL-2) following a NMASCT in a 29-year-old woman with relapsed Hodgkin's lymphoma. The patient developed severe neurological symptoms approximately 6 weeks following NMASCT associated with low CD4+ cell counts and magnetic resonance imaging (MRI) was consistent with PML. IL-2 therapy resulted in increasing CD4+ counts and progressive resolution of neurological symptoms. Disruption of IL-2 therapy led to neurological deterioration, which responded to reinstitution of IL-2 therapy. The patient's lymphoma initially progressed following NMASCT, but has responded to donor leukocyte infusions (DLI). This case reiterates the potent GVT potential of NMASCT in patients with Hodgkin's disease. However, it demonstrates the potential for severe complications related to immunosuppression, especially in heavily pretreated patients. The toxicity after NMASCT should not be understated and will need to be explored further.

Adult↗
PubMed2002

Gemtuzumab ozogamicin (Mylotarg) monotherapy for relapsed AML after hematopoietic stem cell transplant: efficacy and incidence of hepatic veno-occlusive disease.

Gemtuzumab ozogamicin (GO) (Mylotarg, CMA-676) is a novel chemotherapeutic agent consisting of an anti-CD33 monoclonal antibody linked to calicheamicin, and is associated with a 30% response rate in patients with CD33-positive acute myeloid leukemia (AML) in first relapse. GO therapy has a 20% incidence of grade 3 or 4 hepatotoxicity, and has recently been associated with hepatic veno-occlusive disease (VOD). The efficacy and toxicity of GO in patients with AML who have relapsed after hematopoietic stem cell transplant (HSCT) is unknown, as this population was largely excluded from phase II studies. We reviewed the outcomes of eight consecutive patients with AML who received GO following relapse after HSCT. Two (25%) had responses to GO. One patient, who had had two previous HSCT and prior hyperbilirubinemia, developed severe VOD and died 14 days after GO therapy. The other seven patients did not meet diagnostic criteria for VOD. We conclude that GO can be safe and effective in patients who relapse following HSCT, but that caution is warranted in patients with multiple risk factors for VOD.

Acute Disease↗
PubMed2001

Reduction in immunosuppression as initial therapy for posttransplant lymphoproliferative disorder: analysis of prognostic variables and long-term follow-up of 42 adult patients.

BACKGROUND: Posttransplant lymphoproliferative disorder (PTLD) is an Epstein-Barr virus-associated malignancy that occurs in the setting of pharmacologic immunosuppression after organ transplantation. With the increased use of organ transplantation and intensive immunosuppression, this disease is becoming more common. We explore reduction in immunosuppression as an initial therapy for PTLD. METHODS: We analyzed our organ transplant patient database to identify patients with biopsy-proven PTLD who were initially treated with reduction of their immunosuppressive medications with or without surgical resection of all known disease. RESULTS: Forty-two adult patients were included in this study. Thirty patients were treated with reduction in immunosuppression alone. Twelve patients were treated with both reduction in immunosuppression and surgical resection of all known disease. Thirty-one of 42 patients (73.8%) achieved a complete remission. Of those patients who were treated with reduction in immunosuppression alone, 19 of 30 (63%) responded with a median time to documentation of response of 3.6 weeks. Multivariable analysis showed that elevated lactate dehydrogenase (LDH) ratio, organ dysfunction, and multi-organ involvement by PTLD were independent prognostic factors for lack of response to reduction in immunosuppression. In patients with none of these poor prognostic factors, 16 of 18 (89%) responded to reduction in immunosuppression in contrast to three of five (60%) with one risk factor and zero of seven (0%) with two to three factors present. The analysis also showed that increased age, elevated LDH ratio, severe organ dysfunction, presence of B symptoms (fever, night sweats, and weight loss), and multi-organ involvement by PTLD at the time of diagnosis are independent prognostic indicators for poor survival. With median follow-up of 147 weeks, 55% of patients are alive with 50% in complete remission. CONCLUSIONS: Reduction in immunosuppression is an effective initial therapy for PTLD. Clinical prognostic factors may allow clinicians to identify which patients are likely to respond to reduction in immunosuppression.

Adolescent↗
PubMed2001

Identification and characterization of a low oxygen response element involved in the hypoxic induction of a family of Saccharomyces cerevisiae genes. Implications for the conservation of oxygen sensing in eukaryotes.

An organism's ability to respond to changes in oxygen tension depends in large part on alterations in gene expression. The oxygen sensing and signaling mechanisms in eukaryotic cells are not fully understood. To further define these processes, we have studied the Delta9 fatty acid desaturase gene OLE1 in Saccharomyces cerevisiae. We have confirmed previous data showing that the expression of OLE1 mRNA is increased in hypoxia and in the presence of certain transition metals. OLE1 expression was also increased in the presence of the iron chelator 1,10-phenanthroline. A 142-base pair (bp) region 3' to the previously identified fatty acid response element was identified as critical for the induction of OLE1 in response to these stimuli using OLE1 promoter-lacZ reporter constructs. Electromobility shift assays confirmed the presence of an inducible band shift in response to hypoxia and cobalt. Mutational analysis defined the nonameric sequence ACTCAACAA as necessary for transactivation. A 20-base pair oligonucleotide containing this nonamer confers up-regulation by hypoxia and inhibition by unsaturated fatty acids when placed upstream of a heterologous promoter in a lacZ reporter construct. Additional yeast genes were identified which respond to hypoxia and cobalt in a manner similar to OLE1. A number of mammalian genes are also up-regulated by hypoxia, cobalt, nickel, and iron chelators. Hence, the identification of a family of yeast genes regulated in a similar manner has implications for understanding oxygen sensing and signaling in eukaryotes.

Base Sequence↗
PubMed2001

Allogeneic cell therapy for patients who relapse after autologous stem cell transplantation.

Allogeneic donor leukocytes can be used after nonmyeloablative conditioning to exploit their graft-versus-tumor (GVT) activity in the setting of reduced conditioning-regimen toxicity. This approach may be particularly useful for patients who relapse after autologous stem cell transplantation (SCT). However, GVT activity, toxicity, and ability to establish mixed chimerism may differ in patients who were heavily pretreated prior to SCT compared with patients treated earlier in the course of their disease. We have performed a series of studies of nonmyeloablative allogeneic transplantation and present data on the subset of 14 patients treated for relapse after autologous SCT: 4 patients received no conditioning and unstimulated donor leukocyte infusions (DLI), 10 patients received conditioning with fludarabine and cyclophosphamide followed by unstimulated or granulocyte-colony-stimulating factor (G-CSF)-stimulated allogeneic peripheral blood stem cells (PBSCs), 4 patients received no graft-versus-host disease (GVHD) prophylaxis, and 10 patients received cyclosporine GVHD prophylaxis. All but 1 patient had sustained donor chimerism at least 30 days after allogeneic cell therapy (ACT), and 8 patients had more than 80% donor chimerism after ACT. Acute GVHD developed in 11 patients (grade III-IV, n = 6). Aplasia was more frequent in the patients receiving unstimulated PBSCs, despite the development of mixed chimerism. There were 6 complete responses and 4 partial responses; response was independent of conditioning and growth-factor stimulation of the donor graft. Five patients died of treatment-related causes and 4 patients died from progressive disease. Four patients remained alive 27 to 194 weeks (median, 66 weeks) after ACT. Prior autologous SCT may define a subset of patients at particularly high risk for GVHD and other toxicity after ACT. However, these data show that ACT with either DLI or G-CSF-stimulated blood cells results in direct GVT activity in some patients with Hodgkin's disease, myeloma, and non-Hodgkin's lymphoma, even after relapse from autologous SCT. Most patients developed donor chimerism with minimal conditioning. Alternative prophylactic regimens that control GVHD while maintaining GVT are needed to improve outcomes in these heavily pretreated patients.

Adolescent↗
PubMed2001

Novel approaches to allogeneic stem cell therapy.

Traditionally, allogeneic haematopoietic stem cell transplantation (SCT) has involved administration of myeloablative doses of chemotherapy and/or radiation that may cure many patients with haematologic diseases. The high morbidity and mortality associated with the intensive conditioning regimen limits allogeneic SCT to younger and healthier patients. However, it is now known that successful allogeneic SCT is dependent, at least in part, on the antitumour properties of the donor graft independent of the conditioning regimen. This potent 'graft versus tumour' (GVT) effect can now be exploited for clinical benefit. The best evidence of a direct GVT reaction comes from the use of donor leukocyte infusions (DLI). For many patients with relapsed leukaemia after allogeneic SCT, DLI re-establishes complete and durable remissions. This has suggested a novel approach to allogeneic cell therapy (ACT) using non-myeloablative, but immunosuppressive conditioning regimens to permit engraftment of allogeneic stem cells and lymphocytes. Engrafted donor cells would then provide GVT activity in the setting of reduced conditioning regimen toxicity. The ability to minimise toxicity and maximise the immunologic GVT effect will make allogeneic transplantation applicable to patients typically ineligible for conventional allogeneic SCT. Response rates with this strategy have been impressive, although toxicity related to graft versus host disease (GVHD) and other complications remains a concern. Current trials have involved heterogeneous groups of patients using various conditioning regimens. Many issues remain unsettled, including identification of the most appropriate tumour targets and definition of the most effective, least toxic conditioning regimen. In addition, the durability of response is unknown. Nevertheless, the use of non-myeloablative conditioning and ACT may provide a new paradigm for allogeneic cell transplantation and the immunotherapy of cancer.

Clinical Trials as Topic↗
PubMed2000

Treatment of relapsed leukemia after unrelated donor marrow transplantation with unrelated donor leukocyte infusions.

The efficacy and toxicity of donor leukocyte infusions (DLI) after unrelated donor bone marrow transplantation (BMT) is largely unknown. We identified 58 recipients of unrelated DLI (UDLI) for the treatment of relapsed disease from the National Marrow Donor Program database. A retrospective analysis was performed to determine response, toxicity, and survival after UDLI and to identify factors associated with successful therapy. UDLI was administered for relapsed chronic myelogenous leukemia (CML) (n = 25), acute myelogenous leukemia (AML) (n = 23), acute lymphoblastic leukemia (ALL) (n = 7), and other diseases (n = 3). Eight patients were in complete remission (CR) before UDLI, and 50 were evaluable for response. Forty-two percent (95% confidence interval [CI], 28%-56%) achieved CR, including 11 of 24 (46%; 95% CI, 26%-66%) with CML, 8 of 19 (42%; 95% CI, 20%-64%) with AML, and 2 of 4 (50%; 95% CI, 1%-99%) with ALL. The estimated probability of disease-free survival (DFS) at 1 year after CR was 65% (95% CI, 50%-79%) for CML, 23% (95% CI, 9%-38%) for AML, and 30% (95% CI, 6%-54%) for ALL. Acute graft-versus-host disease (GVHD) complicated UDLI in 37% of patients (grade II-IV, 25%). A total of 13 of 32 evaluable patients (41%) developed chronic GVHD. There was no association between cell dose administered and either response or toxicity. In a multivariable analysis, only a longer interval from BMT to relapse and BMT to UDLI was associated with improved survival and DFS, respectively. UDLI is an acceptable alternative to other treatment options for relapse after unrelated donor BMT. (Blood. 2000;95:1214-1221)

Analysis of Variance↗
PubMed2000

Soluble interleukin-2 receptor concentration as a biochemical indicator for acute graft-versus-host disease after allogeneic bone marrow transplantation.

When interleukin-2 (IL-2) binds to the IL-2 receptor (IL2-R) on activated T cells, a soluble portion of the receptor (sIL2-R) is released. After allogeneic bone marrow transplantation (BMT), the serum concentration of sIL2-R may, therefore, be a useful surrogate marker for T cell activation that results in acute graft-versus-host disease (aGVHD). To determine if the sIL2-R concentration is a useful marker to help establish a diagnosis of aGVHD, serial sIL2-R concentrations were measured weekly for 4 weeks in 43 patients after allogeneic BMT. Grafts were from HLA-matched siblings (n = 33), 5/6 HLA-matched siblings (n = 3) or matched unrelated donors (n = 7). GVHD prophylaxis included cyclosporine A (CSA)/methotrexate (MTX) (n = 25), solumedrol/CSA (n = 15), or T cell depletion (n = 3). Twenty-three patients developed aGVHD (Grade I, 7; Grade II, 12; Grade III, 4) a median of 28 days after transplant. There was a significant association between a clinical diagnosis of aGVHD and an increase in the sIL2-R concentration (p < 0.001). The mean percent increase (+/-SE) over baseline for patients with a clinical diagnosis of aGVHD was 294% (+/-57%) by week 2 (n = 12), 431% (+/-116%) by week 3 (n = 14), and 650% (+/-315%) by week 4 (n = 9) after BMT. For each 100% increase over baseline, the likelihood of having aGVHD increased by 18%. Six of 20 patients without aGVHD became critically ill and exhibited marked increases in sIL2-R concentrations, similar to patients with a clinical diagnosis of aGVHD who never became critically ill. Fourteen patients without aGVHD who did not become critically ill exhibited negligible increases of sIL2-R in 2- to 4-week period after BMT. These data suggest that serial measurements sIL2-R concentration are helpful in establishing the diagnosis of aGVHD, but are not useful in the most acutely ill patients.

Acute Disease↗
PubMed2000

Phase I trial of TALL-104 cells in patients with refractory metastatic breast cancer.

The human cytotoxic T-cell line TALL-104 displays antitumor effects in animals with implanted and spontaneous malignancies. A Phase I trial was conducted to determine toxicity of TALL-104 cell therapy in women with metastatic refractory breast cancer. Fifteen patients with metastatic infiltrating ductal (n = 12), lobular (n = 2), or medullary (n = 1) carcinoma received escalating doses of lethally irradiated TALL-104 cells (three patients/group received 10(6), 3 x 10(6), 10(7), 3 x 10(7), and 10(8) cells/kg) for 5 consecutive days (induction course). Patients without progressive disease received monthly maintenance 2-day infusions at the same dose level. Mild grade I/II toxicity developed in 11 patients regardless of cell dose. One grade IV toxicity consequent to hepatic tumor necrosis occurred in a patient given 10(8) cells/kg, 3 weeks after the induction course. Nine patients progressed within 1 month from induction, and five patients had stable disease for 2-6 months. One patient (at 3 x 10(7)/kg) had improvement of liver metastases and ascites, and a second patient (at 10(6)/kg) experienced a dramatic relief in bone pain. Increases in blood natural killer cell activity and levels of IFN-gamma, interleukin-10, and activation markers (soluble interleukin-2 receptor and soluble intercellular adhesion molecule-1) were often seen. Only one patient developed anti-HLA class I antibody responses against TALL-104 cells; specific CTL activity developed in three patients during induction and in four patients during the maintenance boosts. In conclusion, TALL-104 cells were well tolerated by patients with metastatic breast cancer at the doses and regimen tested. The clinical responses observed in this preliminary trial demonstrate that further investigation of TALL-104 cell therapy is warranted.

Adult↗