Biomedical subjects

Leslie Popplewell

Publications and source records attributed to Leslie Popplewell.

9 recordsLinked to original sources

PubMed2006

Targeted total marrow irradiation using three-dimensional image-guided tomographic intensity-modulated radiation therapy: an alternative to standard total body irradiation.

Total body irradiation (TBI) is an important part of bone marrow transplantation conditioning regimens. In TBI, dose escalation is difficult, because of associated normal organ toxicities. A method to deliver a more targeted dose of TBI preferentially to sites of greatest tumor burden is needed to reduce the dose to normal organs, reduce toxicities, and permit dose escalation. The purpose of this study was to evaluate, through a dosimetric analysis, the potential advantages and feasibility of selectively delivering targeted myeloablative doses of radiation to bone and marrow using a recently developed image-guided tomographic intensity-modulated radiation therapy delivery system (helical tomotherapy). Whole-body computed tomography datasets from 3 patients, age 5, 20, and 53 years, were used for treatment planning studies to evaluate 2 targeted TBI strategies: total marrow irradiation (TMI), in which the target region was defined as the skeletal bone, and total marrow and lymphoid irradiation (TMLI), in which the target regions were defined as bone, major lymph node chains, liver, spleen, and sanctuary sites, such as brain. Organ doses and dose distributions were compared with those in conventional TBI. A 1.7- to 7.5-fold reduction in median organ doses was observed with TMI and TMLI compared with conventional TBI. With this more targeted approach, a dose-volume histogram analysis predicted the potential to escalate the dose to bone (and containing marrow) up to 20 Gy, while maintaining doses to normal organs at lower levels than in conventional TBI to 12 Gy. Results were similar for the adult and pediatric patients, indicating that this form of targeted TBI will be applicable to most patients regardless of frame size. TMI to 10 Gy was delivered as part of a tandem transplant regimen to the 53-year-old patient with multiple myeloma. Clinical results confirmed the treatment planning predictions. After TMI, the patient experienced the expected blood count nadir, followed by successful engraftment. Grade 2 nausea and grade 1 emesis occurred only briefly on day 2 of TMI. Skin erythema, oral mucositis, esophagitis, and enteritis were not observed. This report demonstrates the feasibility and potential dosimetric advantages of selectively delivering myeloablative doses of radiation to bone and marrow using an image-guided tomographic intensity-modulated radiation therapy delivery system. Organ doses are substantially lower than those associated with standard TBI and predict the potential to significantly reduce associated toxicities and allow for dose escalation. The results also suggest that this form of targeted TBI may have potential advantages over other forms of targeted TBI, such as radioimmunotherapy or bone-seeking radionuclide therapy. Ongoing clinical trials will define the maximum TMI and TMLI doses achievable and define the potential advantages and limitations of this new approach for patients undergoing hematopoietic stem cell transplantation.

Adult↗

PubMed2006

Does follicularity in large cell lymphoma predict outcome after autologous stem cell transplantation?

The purpose of this study was to evaluate whether follicular histology in large cell lymphoma influences treatment outcomes after autologous stem cell transplantation (ASCT). It remains an area of controversy whether the natural history of follicular large cell lymphoma (FLCL) is akin to diffuse large cell lymphoma (DLCL) with curative potential or is more similar to indolent follicular lymphomas with a pattern of late relapses after intensive chemotherapy. Although ASCT is a potentially curative treatment for patients with recurrent DLCL, the effectiveness of this approach in patients with FLCL is unclear. We undertook a retrospective analysis of 332 patients with large cell lymphoma who underwent ASCT at the City of Hope Comprehensive Cancer Center. With a median follow-up of 31 months, the projected 10-year overall survival and disease-free survival were similar between patients with FLCL and DLCL. Analysis of prognostic factors demonstrated that although age, chemotherapy refractoriness, and disease status at the time of ASCT were predictive of overall survival/disease-free survival, follicularity did not influence the outcome. Furthermore, the similar plateau in the survival curve for the DLCL and FLCL patients suggests that the behavior of FLCL is similar to that of DLCL and that FLCL is potentially curable with ASCT.

Adult↗

PubMed2006

Comparison of reduced-intensity and conventional myeloablative regimens for allogeneic transplantation in non-Hodgkin's lymphoma.

Reduced-intensity regimens (RIRs) are being used with increasing frequency in patients with non-Hodgkin's lymphoma (NHL) undergoing allogeneic transplantation. The impact of dose reduction on relapse and survival has not been extensively studied. We performed a retrospective analysis of 88 patients conditioned with conventional myeloablative regimens (CMRs) (n = 48) and an RIR (n = 40) of fludarabine 125 mg/m(2) and melphalan 140 mg/m(2). Compared with the patients receiving CMR, those receiving RIR were older, had more often failed autologous transplantation, and had more frequently received peripheral blood and unrelated donor transplants. Graft-versus-host disease prophylaxis was provided with cyclosporine + methotrexate +/- prednisone for the CMR and with cyclosporine + mycophenolate +/- methotrexate for the RIR. The relapse rate was significantly lower in the patients receiving CMR than in those receiving RIR (13% vs 28%; P = .05). The 1-year transplantation-related mortality rate was 33% for CMR and 28% for RIR (P = .40). Kaplan-Meier 2-year overall survival and progression-free survival were 52% and 46% for CMR versus 53% and 40% for RIR (P = not significant). Using cumulative incidence functions based on competing risks, univariate analysis, and treatment-related prognostic factors, we found that higher treatment intensity (P = .03; relative risk [RR] = 35%) and absence of previous autologous transplantation (P = .0007; RR = 20%) were associated with a lower relapse rate. Using a Cox univariate proportional hazards model, we found that chemosensitive disease at transplantation (P = .05; RR = 57%) and absence of previous autologous transplantation (P = .002; RR = 37%) were associated with improved survival. Our observation of similar survival in the patients receiving CMR and those receiving RIR confirms that RIRs are feasible alternatives for high-risk patients with NHL; however, the data suggest that reduced treatment intensity and previous autologous transplantation are associated with increased relapse.

Adolescent↗

PubMed2005

Longitudinal assessment of hematopoietic abnormalities after autologous hematopoietic cell transplantation for lymphoma.

PURPOSE: Autologous hematopoietic cell transplantation (HCT) is being increasingly used as an effective treatment strategy for patients with relapsed or refractory Hodgkin's lymphoma (HL) or non-Hodgkin's lymphoma (NHL) but is associated with therapy-related myelodysplasia and acute myeloid leukemia (t-MDS/AML) as a major cause of nonrelapse mortality. The phenomenon of hematopoietic reconstitution after autologous HCT and the role of proliferative stress in the pathogenesis of t-MDS/AML are poorly understood. PATIENTS AND METHODS: Using a prospective longitudinal study design, we evaluated the nature and timing of alterations in hematopoietic progenitors and telomere length after HCT in patients undergoing autologous HCT at City of Hope Cancer Center (Duarte, CA). RESULTS: A significant reduction in primitive and committed progenitors was observed before HCT compared with healthy controls. Further profound and persistent reduction in primitive progenitors but only transient reduction in committed progenitors were seen after HCT. Primitive progenitor frequency in pre-HCT marrow and peripheral-blood stem cells predicted for primitive progenitor recovery after HCT. Shortening of telomere length was observed in marrow cells early after HCT, with subsequent restoration to pre-HCT levels. Patients within this cohort who developed t-MDS/AML had reduced recovery of committed progenitors and poorer telomere recovery, possibly indicating a functional defect in primitive hematopoietic cells. CONCLUSION: Our studies suggest that hematopoietic regeneration after HCT is associated with increased proliferation and differentiation of primitive progenitors. Increased proliferative stress on stem cells bearing genotoxic damage could contribute to the pathogenesis of t-MDS/AML. Extended follow-up of a larger number of patients is required to confirm whether alterations in progenitor and telomere recovery predict for increased risk of t-MDS/AML.

Adult↗

PubMed2005

A phase 1/2 trial of high-dose yttrium-90-ibritumomab tiuxetan in combination with high-dose etoposide and cyclophosphamide followed by autologous stem cell transplantation in patients with poor-risk or relapsed non-Hodgkin lymphoma.

We conducted a phase 1/2 trial of high-dose 90Y-ibritumomab tiuxetan in combination with high-dose etoposide (VP-16) 40 to 60 mg/kg (day -4) and cyclophosphamide 100 mg/kg (day -2) followed by autologous stem cell transplantation (ASCT) in 31 patients with CD20+ non-Hodgkin lymphoma (NHL). Patients underwent dosimetry (day -21) with 5 mCi (185 MBq) 111In-ibritumomab tiuxetan following 250 mg/m2 rituximab, followed a week later by 90Y-ibritumomab tiuxetan to deliver a target dose of 1000 cGy to highest normal organ. Bone marrow biopsy was done on day -7 to estimate radiation dose and stem cells were reinfused when the radiation dose was estimated to be less than 5 cGy. The median 90Y-ibritumomab tiuxetan dose was 71.6 mCi (2649.2 MBq; range, 36.6-105 mCi; range, 1354.2-3885 MBq). Histology included follicular lymphoma (n = 12), diffuse large B-cell (n = 14), and mantle cell (n = 5). The median number of prior chemo-therapy treatments was 2. The treatment was well tolerated. The median times to reach an absolute neutrophil count greater than 500/microL and platelet count more than 20,000/microL were 10 days and 12 days, respectively. There were 2 deaths and 5 relapses. At a median follow-up of 22 months, the 2-year estimated overall survival and relapse-free survival rates are 92% and 78%, respectively. We conclude that high-dose 90Y-ibritumomab tiuxetan can be combined safely with high-dose etoposide and cyclophosphamide without an increase in transplant-related toxicity or delayed engraftment.

Adult↗

PubMed2005

Efficacy of mycophenolate mofetil in the treatment of chronic graft-versus-host disease.

Current treatment of chronic graft-versus-host disease (cGVHD) with prednisone (PSE) alone or with added cyclosporine or tacrolimus still has a very high failure and complication rate, and new treatment approaches are needed for both primary and salvage therapy. Mycophenolate mofetil (MMF) is an immunosuppressive agent currently in use for acute graft-versus-host disease prophylaxis. To determine whether MMF had activity in the treatment of cGVHD, we added MMF to standard cyclosporine, tacrolimus, and/or PSE as salvage/second-line (n = 24) or first-line (n = 10) therapy in 34 patients. Nine (90%) of 10 patients receiving first-line and 18 (75%) of 24 receiving second-line MMF therapy responded. Twelve (35%) patients had a complete remission, 15 (44%) had a partial remission, 5 (15%) had stable disease, and only 2 (6%) had progressive disease. Out of 30 patients receiving PSE, 22 (73%) were able to decrease PSE doses (median decrease of 50%; range, 25%-100%). With a median follow-up of 24 months (range, 6-28 months), 29 (85%) patients are alive. Three patients had to discontinue MMF because of abdominal cramps within 3 months of starting treatment. These data suggest that MMF is an active, well-tolerated agent in the treatment of cGVHD and may have a beneficial effect on the survival of patients with this complication.

Chronic Disease↗

PubMed2002

T-cell clones can be rendered specific for CD19: toward the selective augmentation of the graft-versus-B-lineage leukemia effect.

Relapse of B-lineage acute lymphoblastic leukemia (B-ALL) after allogeneic hematopoietic stem cell transplantation (HSCT) commonly results from the failure of a graft-versus-leukemia (GVL) effect to eradicate minimal residual disease. Augmenting the GVL effect by the adoptive transfer of donor-derived B-ALL-specific T-cell clones is a conceptually attractive strategy to decrease relapse rates without exacerbating graft-versus-host disease (GVHD). Toward this end, we investigated whether a genetic engineering approach could render CD8(+) cytotoxic T lymphocytes (CTLs) specific for tumor cells that express the B-cell lineage cell surface molecule CD19. This was accomplished by the genetic modification of CTLs to express a chimeric immunoreceptor composed of a CD19-specific single-chain immunoglobulin extracellular targeting domain fused to a CD3-zeta intracellular signaling domain. CD19-redirected CTL clones display potent CD19-specific lytic activity and chimeric immunoreceptor-regulated cytokine production and proliferation. Because B-ALL cells can evade T-cell/natural killer- cell recognition by down-regulation of cell surface accessory molecules that participate in the formation of a functional immunologic synapse, we compared the CD19-specific effector function of genetically modified CD8(+) CTLs toward CD19(+) cells with disparate levels of intercellular adhesion molecule 1 (ICAM-1), leukocyte function-associated antigen 1 (LFA-1), and LFA-3. We observed that recognition of B-lineage tumor lines by CD19-specific CTLs was not impaired by low levels of ICAM-1, LFA-1, and LFA-3 cell surface expression, a functional attribute that is likely a consequence of our high-affinity CD19-specific chimeric immunoreceptor. Furthermore, the CD19-specific CTLs could lyse primary B-ALL blasts. These preclinical observations form the basis for implementing clinical trials using donor-derived CD19-specific T-cell clones to treat or prevent relapse of B-ALL after allogeneic HSCT.

Adoptive Transfer↗

PubMed2002

21q22 balanced chromosome aberrations in therapy-related hematopoietic disorders: report from an international workshop.

The International Workshop on the relationship between prior therapy and balanced chromosome aberrations in therapy-related myelodysplastic syndromes (t-MDS) and therapy-related acute leukemia (t-AL) identified 79 of 511 (15.5%) patients with balanced 21q22 translocations. Patients were treated for their primary disease, including solid tumors (56%), hematologic malignancy (43%), and juvenile rheumatoid arthritis (single case), by radiation therapy (5 patients), chemotherapy (36 patients), or combined-modality therapy (38 patients). 21q translocations involved common partner chromosomes in 81% of cases: t(8;21) (n = 44; 56%), t(3;21) (n = 16; 20%), and t(16;21) (n = 4; 5%). Translocations involving 15 other partner chromosomes were also documented with involvement of AML1(CBFA2/RUNX1), identifying a total of 23 different 21q22/AML1 translocations. The data analysis was carried out on the basis of five subsets of 21q22 cases, that is, t(8;21) with and without additional aberrations, t(3;21), t(16;21), and other 21q22 translocations. Dysplastic features were present in all 21q22 cases. Therapy-related acute myeloid leukemia (t-AML) at presentation was highest in t(8;21) (82%) and lowest in t(3;21) (37.5%) patients. Cumulative drug dose exposure scores for alkylating agents (AAs) and topoisomerase II inhibitors indicated that t(3;21) patients received the most intensive therapy among the five 21q22 subsets, and the median AA score for patients with secondary chromosome 7 aberrations was double the AA score for the entire 21q22 group. All five patients who received only radiation therapy had t(8;21) t-AML. The median latency and overall survival (OS) for 21q22 patients were 39 and 14 months (mo), compared to 26 and 8 mo for 11q23 patients, 22 and 28 mo for inv(16), 69 and 7 mo for Rare recurring aberrations, and 59 and 7 mo for Unique (nonrecurring) balanced aberration (latency P < or = 0.016 for all pairwise comparisons; OS, P < or = 0.018 for all pairwise comparisons). The percentages of 21q22 patients surviving 1 year, 2 years, and 5 years were 58%, 33%, and 18%, respectively. Noticeable differences were observed in median OS between 21q22 patients (n = 7) receiving transplant (BMT) (31 mo) compared to 21q22 patients who received intensive non-BMT therapy (n = 46) (17 mo); however, this was nonsignificant because of the small sample size (log-rank, P = 0.33). t-MDS/t-AML with balanced 21q22 aberrations was associated with prior exposure to radiation, epipodophyllotoxins, and anthracyclines, dysplastic morphologic features, multiple partner chromosomes, and longer latency periods when compared to 11q23 and inv(16) t-MDS/AML Workshop subgroups. In general, patients could be divided into two prognostic risk groups, those with t(8;21) (median OS, 19 mo) and those without t(8;21) (median OS, 7 mo) leukemia (log-rank, P = 0.0007).

Adolescent↗

PubMed2002

Therapy-related acute myeloid leukemia/myelodysplasia with balanced 21q22 translocations.

The morphologic and immunophenotypic findings of 36 cases of 21q22 acute myeloid leukemia (AML) and myelodysplasia (MDS) were compared, including 14 de novo t(8;21) AMLs, 11 t(8;21) therapy-related AML/MDS cases, and 11 therapy-related AML/MDS cases with other 21q22 balanced translocations [t(n;21)]. Cases were evaluated for the presence of Auer rods, distinct chunky cytoplasmic blast cell granules, promyelocyte increase, cytoplasmic perinuclear clearing (hofs) of blast cells, eosinophil increase, andfeatures of associated trilineage dysplasia. Results of immunophenotyping studies for CD19, CD34, and CD56 expression were compared. Cases of de novo and therapy-related t(8;21) disease shared common morphologic features of chunky cytoplasmic granules, perinuclear hofs, and promyelocyte increases that were not seen consistently in the t(n;21) group of t-AML/MDS cases. Immunophenotypic similarities also were observed between the 2 t(8;21) groups. De novo and therapy-related t(8;21) disease, however, differed by the frequent presence of associated dysplasia in both t-AML/MDS groups, which was infrequent in the de novo t(8;21) group. Therapy-related AMI/MDS with t(8;21) shares characteristic morphologic and immunophenotypic features with de novo t(8;21) AML, but frequently also occurs with associated myelodysplastic changes, similar to other therapy-related acute leukemias.

Antigens, CD19↗