Kevin Sheehan

Production of myeloid dendritic cells (DC) pulsed with tumor-specific idiotype protein for vaccination of patients with multiple myeloma

BACKGROUND Immunotherapy of cancer with DC vaccines has produced encouraging results in clinical trials. Antigen (Ag)-pulsed DC have elicited CD4+ and CD8+ T-cell immunity and tumor regression in humans. However, there is no standard method of DC production. The DC phenotype, number and Ag-loading process used in these studies have varied, making comparisons between trials difficult. METHODS In the present report a reproducible method was developed for the production of a DC-based vaccine. Monocytes were enriched by adhesion from healthy donor apheresis products and cultured with growth factors for maturation into DC. The cells were loaded with the tumor Ag idiotype proteins from patients with multiple myeloma. DC culture and Ag loading were performed in an automated and closed system. The DC product was characterized for phenotype by flow cytometry and for function in Ag uptake and Ag presentation. RESULTS These monocyte-derived DC expressed high levels of costimulatory molecules (CD80/86). Ag-pulsed DC functioned to induce allogeneic proliferative lymphocyte responses and Ag-specific cytotoxic T lymphocyte (CTL) responses. The DC viability, phenotype and function were well preserved following prolonged frozen storage. Aliquots from the product of a single DC preparation could be used for sequential vaccinations without batch to batch variability. DISCUSSION Ag-pulsed DC can be reproducibly generated for clinical use. These standardized methods are now being employed for a clinical trial to evaluate idiotype-pulsed DC vaccine therapy following non-myeloablative transplant for the treatment of multiple myeloma.

Long-term follow-up of patients with diffuse large B-cell non-Hodgkin's lymphoma receiving purged autografts after induction failure

Patients with diffuse large B-cell lymphoma (DLBCL) who do not achieve a complete response to front-line combination chemotherapy are often offered high-dose therapy and autologous hematopoietic cell transplantation (AHCT). However, the efficacy of this therapy in this patient population has been addressed in only a few published reports. We retrospectively analyzed the outcomes of patients with a diagnosis of de novo DLBCL who underwent AHCT at our center between 1988 and 2002, and identified 43 consecutive patients who had not achieved a CR before AHCT, although most showed at least a partial response (PR) to either induction or subsequent salvage chemotherapy. A total of 15 patients received a conditioning regimen that included high-dose chemotherapy with fractionated TBI (FTBI), whereas 28 patients received high-dose chemotherapy only. All autografts were treated ex vivo with MoAbs and complement in an effort to remove any residual malignant B cells. A total of 33 (77%) patients achieved a CR after AHCT. With a median follow-up of 7.3 years, the 5-year OS was 69% and EFS was 59%. Four patients died from non-relapse mortality. By univariate analyses, the following characteristics did not significantly impact OS: disease stage at diagnosis, age-adjusted IPI (International Prognostic Index) score, age ⩾40 years, earlier radiotherapy and the use of FTBI in the conditioning regimen. These results confirm the long-term efficacy of AHCT for patients with DLBCL after induction failure.

Infusion of donor-derived CD8+ memory T cells for relapse following allogeneic hematopoietic cell transplantation

Murine models showed that CD8+CD44hi memory T (TM) cells could eradicate malignant cells without inducing graft-versus-host disease (GVHD). We evaluated the feasibility and safety of infusing freshly isolated and purified donor-derived phenotypic CD8+ TM cells into adults with disease relapse after allogeneic hematopoietic cell transplantation (HCT). Phenotypic CD8 TM cells were isolated after unmobilized donor apheresis using a tandem immunomagnetic selection strategy of CD45RA depletion followed by CD8+ enrichment. Fifteen patients received CD8+ TM cells at escalating doses (1 × 106, 5 × 106, or 10 × 106 cells per kg). Thirteen received cytoreduction before CD8+ TM cell infusion, and 9 had active disease at the time of infusion. Mean yield and purity of the CD8+ TM infusion were 38.1% and 92.8%, respectively; >90% had CD8+ T effector memory phenotype, cytokine expression, and secretion profile. No adverse infusional events or dose-limiting toxicities occurred; GVHD developed in 1 patient (grade 2 liver). Ten patients (67%) maintained or achieved response (7 complete response, 1 partial response, 2 stable disease) for at least 3 months after infusion; 4 of the responders had active disease at the time of infusion. With a median follow-up from infusion of 328 days (range, 118-1328 days), median event-free survival and overall survival were 4.9 months (95% confidence interval [CI], 1-19.3 months) and 19.6 months (95% CI, 5.6 months to not reached), respectively. Collection and enrichment of phenotypic CD8+ TM cells is feasible, well tolerated, and associated with a low incidence of GVHD when administered as a manipulated infusion of donor lymphocytes in patients who have relapsed after HCT. This trial was registered at www.clinicaltrials.gov as #NCT01523223.