Dominic Wall

A phase I clinical trial of dendritic cell immunotherapy in HCV-infected individuals.

BACKGROUND & AIMS HCV patients who fail conventional interferon-based therapy have limited treatment options. Dendritic cells are central to the priming and development of antigen-specific CD4(+) and CD8(+) T cell immunity, necessary to elicit effective viral clearance. The aim of the study was to investigate the safety and efficacy of vaccination with autologous dendritic cells loaded with HCV-specific cytotoxic T cell epitopes. METHODS We examined the potential of autologous monocyte-derived dendritic cells (MoDC), presenting HCV-specific HLA A2.1-restricted cytotoxic T cell epitopes, to influence the course of infection in six patients who failed conventional therapy. Dendritic cells were loaded and activated ex vivo with lipopeptides. In this phase 1 dose escalation study, all patients received a standard dose of cells by the intradermal route while sequential patients received an increased dose by the intravenous route. RESULTS No patient showed a severe adverse reaction although all experienced transient minor side effects. HCV-specific CD8(+) T cell responses were enumerated in PBMC by ELIspot for interferon-gamma. Patients generated de novo responses, not only to peptides presented by the cellular vaccine but also to additional viral epitopes not represented in the lipopeptides, suggestive of epitope spreading. Despite this, no increases in ALT levels were observed. However, the responses were not sustained and failed to influence the viral load, the anti-HCV core antibody response and the level of circulating cytokines. CONCLUSIONS Immunotherapy using autologous MoDC pulsed with lipopeptides was safe, but was unable to generate sustained responses or alter the outcome of the infection. Alternative dosing regimens or vaccination routes may need to be considered to achieve therapeutic benefit.

In vivo tracking of dendritic cells in patients with multiple myeloma.

Dendritic cell (DC) immunotherapy is being actively studied in multiple myeloma (MM). We aimed to use positron emission tomography or single positron emission tomography to determine the in vivo distribution of monocyte-derived nonmatured DC or matured DC (mDC) administered to patients with MM. Eligible patients had stable or slowly progressive MM and elevated serum MUC-1 or MUC-1 expression on marrow plasma cells. DCs were derived from granulocyte-macrophage colony-stimulating factor+interleukin-13 stimulated autologous monocytes, pulsed with mannan-MUC1 fusion protein, and matured by FMKp and interferon-γ. Before injection, DCs were labeled with either 18fluorine-fluorodeoxyglucose, 111indium-oxine or 64copper-pyruvaldehyde-bis-N-4-methylthiosemicarbazone. Labeled DCs were given either as a single intravenous dose or by concurrent subcutaneous (SC), intradermal (ID), and intranodal routes. 18Fluorine-fluorodeoxyglucose tracking was unsuccessful owing to high radiolabel efflux. 64Copper-pyruvaldehyde-bis-N-4-methylthiosemicarbazone-labeled mDC (n=2 patients) demonstrated tracking to regional nodes but quantitation was also limited owing to cellular efflux. 111Indium-oxine, however, gave reproducible tracking of both nmDc and mDC (n=6) to regional lymph node after either SC or ID administration, with mDC revealing superior migration to regional lymph node. SC and ID routes produced similar levels of DC migration.

Peripheral Blood CD34+ Cell Enumeration as a Predictor of Apheresis Yield: An Analysis of More Than 1,000 Collections

The role of the peripheral blood (PB) CD34(+) cell count in predicting the CD34(+) cell yield in hematopoietic progenitor cell apheresis collections is well established. However, sometimes unexpectedly poor CD34(+) cell yields are obtained. To determine the effect, if any, of a range of factors on the ability of the PB CD34(+) count to predict collection CD34(+) cell count, we performed a retrospective analysis on consecutive hematopoietic progenitor cell apheresis collections between 2004 and 2008. Factors investigated included mobilization regimen, PB white blood cell count, body weight, and disease. After exclusion of collections involving apheresis complications, a total of 1,225 PB CD34(+) cell results with corresponding collection CD34(+) cell results from 458 patients were analyzed. Although differences in the median PB CD34(+) cell counts and collection CD34(+) cell counts were seen between mobilized collections with chemotherapy plus granulocyte colony-stimulating factor and those with granulocyte colony-stimulating factor alone, the predictive capability of the PB CD34(+) cell count for the collection CD34(+) cell yield remained similar. Although poorer collection efficiencies were observed in the myelodysplastic syndrome/myeloproliferative disorder diagnostic subgroup, our findings confirm that PB CD34(+) cell analysis remains a powerful and irreplaceable tool for predicting hematopoietic progenitor cell apheresis CD34(+) cell yield.

In vivo tracking of macrophage activated killer cells to sites of metastatic ovarian carcinoma

Radio-labelling of blood cells is an established technique for evaluating in vivo migration of normal cells to sites of pathology such as infection and haemorrhage. A limitation of cellular immunotherapies to induce anti-tumour responses is in part due to the uncertain ability of cellular effectors to reach their intended target. We extended the approach of cell radiolabelling to accurately examine the in vivo distribution of cellular immunotherapy with ex-vivo macrophage activated killer (MAK) cells. We describe the use of two methods of cell labelling for tracking the destination of autologous-derived macrophage activated killer (MAK®) cells linked to the bi-specific antibody MDX-H210 delivered either by intravenous (i.v.) or intraperitoneal (i.p.) injection in ten patients with peritoneal relapse of epithelial ovarian carcinoma. Our results demonstrate the feasibility of generating high numbers and purity of GMP quality MAK cells, which can be radiolabelled with 18F-FDG or 111In-oxime. MAK cell administration produced minimal infusional toxicity and demonstrated a reproducible pattern of in vivo distribution and active in vivo tracking to sites of known tumour following 8 of 16 i.v. infusions or 4 of 6 i.p. infusions. However, the leakage of 18F-FDG limited the ability to confidently confirm the tracking of MAK cells to tumour in all cases and improved PET labels are required. The addition of MDX-H210 bispecific antibody did not alter the distribution of cells to tumour sites, but did accelerate the clearance of i.v. administered MAK cells from the pulmonary circulation. This data demonstrates that cellular cancer immunotherapies may be successfully delivered to the sites of active tumour following either i.v. or i.p. injection in a proportion of patients with metastatic cancer. Incorporation of tracking studies in early cycles of cellular immunotherapy may allow selection of patients who demonstrate successful targeting of the immunotherapy for ongoing treatment.

Pegfilgrastim compared with filgrastim for cytokine-alone mobilization of autologous haematopoietic stem and progenitor cells

Haematopoietic stem and progenitor cells (HSPC) mobilization, using cytokine-alone, is a well-tolerated regimen with predictable mobilization kinetics. Single-dose pegfilgrastim mobilizes HSPC efficiently; however, there is surprisingly little comparative data on its use without chemotherapy for HSPC mobilization. Pegfilgrastim-alone and filgrastim-alone mobilization regimens were compared in 52 patients with haematological malignancy. Pegfilgrastim 12 mg (n=20) or 6 mg (n=2) was administered Day 1 (D1) in 22 patients (lymphoma n=17; myeloma n=5). Thirty historical controls (lymphoma n=18; myeloma n=12) received filgrastim 10 mcg/kg daily from D1. Peripheral blood (PB) CD34+ counts reached threshold (⩾5 × 106/L) and apheresis commenced on D4(4–5) and D4(4–6). Median PB CD34+ cell count on D1 of apheresis was similar (26.0 × 106/L (2.5–125.0 × 106/L) and 16.2 × 106/L (2.6–50.7 × 106/L); P=0.06), for pegfilgrastim and filgrastim groups, respectively. Target yield (⩾2 × 106 per kg CD34+ cells) was collected in 20/22 (91%) pegfilgrastim patients and 24/30 (80%) in the filgrastim group (P=0.44), in a similar median number of aphereses (3(1–4) versus 3(2–6), respectively; P=0.85). A higher proportion of pegfilgrastim patients tended to yield ⩾4 × 106 per kg CD34+ cells; 16/22 (73%) versus 14/30 (47%) filgrastim patients (P=0.09). One pegfilgrastim patient developed hyperleukocytosis that resolved without incident. Pegfilgrastim-alone is a simple, well-tolerated, and attractive option for outpatient-based HSPC mobilization with similar mobilization kinetics and efficacy to regular filgrastim.

Positioning a Scientific Community on Unproven Cellular Therapies: The 2015 International Society for Cellular Therapy Perspective

Currently, there are many unproven or insufficiently proven cell-based treatments commercially available for hopeful individuals seeking cures for a variety of conditions. Typically, these so-called “therapies” are currently being advertised, sold and administered to patients, although they fail to achieve recognized biological/medical standards of proof for safety or efficacy. In addition, they are often expensive and offered outside the cover of routine clinical care for treatments, outside the realm of conventional clinical trials supervised and monitored by regulatory agencies. This paper summarizes a position document to be published by the International Society for Cellular Therapy (ISCT) as an open manuscript intended for professionals and patient associations. Avoiding a systematic overview of the relevant peer-reviewed literature and investigations, its purpose is to examine multiple aspects of unproven cell therapy interventions including definitions, manufacturing issues, regulations, economic factors and communication. With this document, the ISCT intends to promote a cooperative approach to facilitate the development of safe and effective therapies while minimizing and balancing risks for patients to ultimately establish a coalition of stakeholders that fulfill the vision of a broad, pro-patient cell therapy alliance...

Regulation of cellular therapy in Australia

Summary Use of cellular products for therapeutic purposes has predominantly been unregulated in Australia until recently. Transplant of haemopoietic progenitor cells (HPC) for bone marrow regeneration is now a routine treatment for many disorders with an established mechanism of facility accreditation. However, other cellular therapies do not have any form of accreditation, are not well evaluated and may be associated with significant risks. On 31 May 2011 the Therapeutic Goods Administration (TGA) implemented a long heralded regulatory biologicals framework for cell and tissue based therapies. The framework currently excludes human HPC, organs for direct transplantation and reproductive materials which are already covered by various forms of existing peer review and accreditation. This new framework is a practical approach for applying regulation based on the risk of the product to the recipient with four classes of product. Class 1 is reserved for the least regulated products and currently does not contain any proposed products. Class 2 will be for minimally manipulated products which will only require manufacturing compliance and evaluation against product and other mandatory standards before entry onto the Australian Register of Therapeutic Goods (ARTG). Class 3 and 4 products will be more than minimally manipulated and these cells and tissues may be used in a non-homologous manner. Class 3 and 4 products will represent a spectrum of risk where Class 4 therapies will represent the highest potential risk to the recipient, with the same requirements for Class 2 approvals but with additional requirements for comprehensive evaluation of a dossier for quality, safety and efficacy of the product. The extent of this quality, safety and efficacy data will depend upon the nature of the product and its associated risks, but will be more comprehensive for Class 4 as opposed to Class 3 products. The only truly contentious feature of this framework is the extremely high cost for dossier evaluation and the puzzling absence of an orphan drug scheme for biologicals.

Human dendritic cells pulsed with specific lipopeptides stimulate autologous antigen‐specific T cells without the addition of exogenous maturation factors

Summary.  Serum‐free culture conditions to generate immature human monocyte‐derived DC (Mo‐DC) were optimized, and the parameters that influence their maturation after exposure to lipopeptides containing CD4+ and CD8+ T‐cell epitopes were examined. The lipopeptides contained a single CD4+ helper T‐cell epitopes, one of a number of human leucocyte antigen (HLA)‐A2‐restricted cytotoxic T‐cell epitope and the lipid Pam2Cys. To ensure complete maturation of the Mo‐DC, we examined (i) the optimal lipopeptide concentration, (ii) the optimal Mo‐DC density and (iii) the appropriate period of exposure of the Mo‐DC to the lipopeptides. The results showed that a high dose of lipopeptide (30 μm) was no more efficient at upregulating maturation markers on Mo‐DC than a low dose (6 μm). There was an inverse relationship between Mo‐DC concentration and the mean fluorescence intensity of maturation markers. In addition, at the higher cell concentrations, the chemotactic capacity of the Mo‐DC towards a cognate ligand, CCL21, was reduced. Thus, high cell concentrations during lipopeptide exposure were detrimental to Mo‐DC maturation and function. The duration of exposure of Mo‐DC to the lipopeptides had little effect on phenotype, although Mo‐DC exposed to lipopeptides for 48 rather than 4 h showed an increased ability to stimulate autologous peripheral blood mononuclear cells to release interferon‐γ in the absence of exogenous maturation factors. These findings reveal conditions for generating mature antigen‐loaded DC suitable for targeted immunotherapy.

Part 4: Interaction between unproven cellular therapies and global medicinal product approval regulatory frameworks

NantKwest, Inc, Culver City, California, USA. ISCT Past Co-Chair, NA LRA Committee 2011–2014, St Jude Children’s Research Hospital, Memphis,Tennessee, USA. ISCT Past Co-Chair, NA LRA Committee 2011–2014. ISCT North America, RegionalVice-President 2014–2016, Department of Pathology, University of Melbourne, Cell Therapies Pty Ltd, East Melbourne,Australia, ISCT Australia & New Zealand, Past RegionalVice President 2012– 2014 and Chair, ISCT ANZ LRA Committee 2014–2016, Andalusian Initiative for Advanced Therapies, Junta de Andalucia, Sevilla, Spain. Chair, ISCT EU LRA Committee 2014–2016, and Moffitt Cancer Center and Research Institute,Tampa, Florida, USA. Chair, ISCT NA LRA Committee 2014–2016. Co-Editor of the Telegraft

A Risk-Adapted Protocol for Delayed Administration of Filgrastim After High-Dose Chemotherapy and Autologous Stem Cell Transplantation

INTRODUCTION The routine use of recombinant human granulocyte-colony stimulating factor (rhG-CSF) after high-dose chemotherapy and autologous stem cell transplantation (auto-SCT) is associated with increased costs. We prospectively explored a strategy that used prophylactic delayed filgrastim only in patients with risk factors. PATIENTS AND METHODS This sequential cohort analysis compared the outcomes of consecutive patients, treated on the risk-adapted protocol (RAP) (risk factors: prior febrile neutropenia; age >60 years; and CD34+ cell infused dose of <2 × 10(6/)/kg), who received filgrastim from day +6 after auto-SCT with a historical cohort (historical day-1 cohort [HD1]), who received filgrastim from day +1. RESULTS Eighty-two patients were treated in the RAP cohort and compared with 115 patients in the HD1 cohort. There were no differences in median age (55 years) or median CD34+ cell dose (5.21 × 10(6)/kg [range, 2-62.2 × 10(6)/kg] vs. 5.24 × 10(6)/kg [range, 2.4-29.8 × 10(6)/kg]). Filgrastim was used for 6 fewer days in the RAP cohort (median 5 days [range, 0-11 days] vs. 11 days [range, 9-47 days]). There was a small absolute but significant difference in median time to neutrophil recovery in the HD1 cohort for the whole group, 10 days (range, 8-46 days) vs. 11 days (range, 9-22 days) (P = .03) and in patients with myeloma; 10 days (range, 9-14 days) vs. 11 days (range, 9-18 days) (P < .0001) as compared to the RAP cohort. There was no difference in median inpatient duration, 13 days (range, 10-26 days) vs. 12 days (range, 1-38 days) (P = .22) and 3-year survival (79% vs. 83% [P = .43]) between HD1 and RAP cohorts respectively. CONCLUSIONS The use of a RAP to identify patients likely to benefit from prophylactic filgrastim is safe and results in cost savings. Patients with myeloma benefit from earlier introduction of filgrastim in terms of neutrophil recovery; this disease-specific observation is an important consideration for future studies.