Kumi Yoshida

DVC1-0101 to Treat Peripheral Arterial Disease: A Phase I/IIa Open-label Dose-escalation Clinical Trial

We here report the results of a Phase I/IIa open-label four dose-escalation clinical study assessing the safety, tolerability, and possible therapeutic efficacy of a single intramuscular administration of DVC1-0101, a new gene transfer vector based on a nontransmissible recombinant Sendai virus (rSeV) expressing the human fibroblast growth factor-2 (FGF-2) gene (rSeV/dF-hFGF2), in patients with peripheral arterial disease (PAD). Gene transfer was done in 12 limbs of 12 patients with rest pain, and three of them had ischemic ulcer(s). No cardiovascular or other serious adverse events (SAEs) caused by gene transfer were detected in the patients over a 6-month follow-up. No infectious viral particles, as assessed by hemagglutination activity, were detected in any patient during the study. No representative elevation of proinflammatory cytokines or plasma FGF-2 was seen. Significant and continuous improvements in Rutherford category, absolute claudication distance (ACD), and rest pain were observed (P < 0.05 to 0.01). To the best of our knowledge, this is the first clinical trial of the use of a gene transfer vector based on rSeV. The single intramuscular administration of DVC1-0101 to PAD patients was safe and well tolerated, and resulted in significant improvements of limb function. Larger pivotal studies are warranted as a next step.

Sustained and NK/CD4+ T Cell-Dependent Efficient Prevention of Lung Metastasis Induced by Dendritic Cells Harboring Recombinant Sendai Virus

We recently demonstrated efficient antitumor immunity against murine tumors using dendritic cells (DCs) activated by recombinant Sendai viruses (rSeVs), and proposed a new concept, “immunostimulatory virotherapy,” for cancer immunotherapy. However, there has been little information on the efficacy of this method in preventing metastatic diseases. In this study, we investigated the efficacy of vaccinating DCs activated by fusion gene-deleted nontransmissible rSeV (rSeV/dF) using a murine model of lung metastasis. Bolus and i.v. administration of DCs harboring rSeV/dF-expressing GFP without pulsation of tumor Ag (DC-rSeV/dF-GFP) 2 days before tumor inoculation showed efficient prevention against lung metastasis of c1300 neuroblastoma, but not of RM-9 prostatic cancer. We found that the timing of DC therapy was critical for the inhibition of pulmonary metastasis of RM-9, and that the optimal effect of DCs was seen 28 days before tumor inoculation. Interestingly, the antimetastatic effect was sustained for over 3 mo, even when administered DCs were already cleared from the lung and organs related to the immune system. Although NK cell activity had already declined to baseline at the time of tumor inoculation, Ab-mediated depletion studies revealed that CD4+ cells as well as the presence of, but not the activation of, NK cells were crucial to the prevention of lung metastasis. These results are the first demonstration of efficient inhibition of lung metastasis via bolus administration of virally activated DCs that was sustained and NK/CD4+ cell-dependent, and may suggest a potentially new mechanism of DC-based immunotherapy for advanced malignancies.

Antagonism of VEGF by genetically engineered dendritic cells is essential to induce antitumor immunity against malignant ascites

Malignant ascitis (MA) is a highly intractable and immunotherapy-resistant state of advanced gastrointestinal and ovarian cancers. Using a murine model of MA with CT26 colon cancer cells, we here determined that the imbalance between the VEGF-A/vascular permeability factor and its decoy receptor, soluble fms-like tryrosine kinase receptor-1 (sFLT-1), was a major cause of MA resistance to dendritic cell (DC)-based immunotherapy. We found that the ratio of VEGF-A/sFLT-1 was increased not only in murine but also in human MA, and F-gene–deleted recombinant Sendai virus (rSeV/dF)-mediated secretion of human sFLT-1 by DCs augmented not only the activity of DCs themselves, but also dramatically improved the survival of tumor-bearing animals associated with enhanced CTL activity and its infiltration to peritoneal tumors. These findings were not seen in immunodeficient mice, indicating that a VEGF-A/sFLT-1 imbalance is critical for determining the antitumor immune response by DC-vaccination therapy against MA. Mol Cancer Ther; 10(3); 540–9. ©2011 AACR.

Impact of deletion of envelope-related genes of recombinant Sendai viruses on immune responses following pulmonary gene transfer of neonatal mice

We demonstrated previously that the additive-type recombinant Sendai virus (rSeV) is highly efficient for use in pulmonary gene transfer; however, rSeV exhibits inflammatory responses. To overcome this problem, we tested newly developed non-transmissible constructs, namely, temperature-sensitive F-deleted vector, rSeV/dF (ts-rSeV/dF) and a rSeV with all the envelope-related genes deleted (rSeV/dFdMdHN), for pulmonary gene transfer in neonatal mice, by assessing their toxicity and immune responses. The gene expression in the lungs of neonatal ICR mice peaked on day 2, then gradually decreased until almost disappearing at 14 days after infection in all constructs. Loss of body weight and mortality rate, however, were dramatically improved in mice treated with SeV/dFdMdHN (mortality=0%, n=41) and ts-rSeV/dF (24.2%, n=33) compared with additive rSeV (70.7%, n=58). Although the deletion of envelope-related genes of SeV had a small impact on the production of antibody and cytotoxic T-lymphocyte activity in both adults and neonates, a dramatic reduction was found in the events related to innate responses, including the production of proinflammatory cytokines, particularly in the case of neonates. These results indicate that pulmonary gene transfer using SeV/dFdMdHN warrants further investigation for its possible use in developing safer therapeutics for neonatal lung diseases, including cystic fibrosis.

Ex Vivo Generation of Highly Purified and Activated Natural Killer Cells from Human Peripheral Blood

Adoptive immunotherapy using natural killer (NK) cells has been a promising treatment for intractable malignancies; however, there remain a number of difficulties with respect to the shortage and limited anticancer potency of the effector cells. We here established a simple feeder-free method to generate purified (>90%) and highly activated NK cells from human peripheral blood-derived mononuclear cells (PBMCs). Among the several parameters, we found that CD3 depletion, high-dose interleukin (IL)-2, and use of a specific culture medium were sufficient to obtain highly purified, expanded (∼200-fold) and activated CD3(-)/CD56(+) NK cells from PBMCs, which we designated zenithal-NK (Z-NK) cells. Almost all Z-NK cells expressed the lymphocyte-activated marker CD69 and showed dramatically high expression of activation receptors (i.e., NKG2D), interferon-γ, perforin, and granzyme B. Importantly, only 2 hours of reaction at an effector/target ratio of 1:1 was sufficient to kill almost all K562 cells, and the antitumor activity was also replicated in tumor-bearing mice in vivo. Cytolysis was specific for various tumor cells, but not for normal cells, irrespective of MHC class I expression. These findings strongly indicate that Z-NK cells are purified, expanded, and near-fully activated human NK cells and warrant further investigation in a clinical setting.

Efficacy and Safety of DVC1-0101 for Intermittent Claudication Secondary to Peripheral Artery Disease: Study Protocol of a Randomized Phase IIb Trial

1.1. Background: We have developed a new gene transfer vector based on nontransmissible recombinant Sendai virus expressing the human fibroblast growth factor-2 gene (DVC1-0101) to treat peripheral arterial disease. A phase I/IIa open-label four dose-escalation clinical trial for critical limb ischemia was completed. We concluded that DVC1-0101 is safe and well tolerated, and resulted in significant improvement of limb function. We present the protocol of the next phase of our study. 1.2. Methods: We plan to conduct a phase IIb clinical trial, which will be a randomized, placebo-controlled, parallel design, single-dose blinded and single center clinical trial in Japan. This study will enroll 60 patients diagnosed with PAD with intermittent claudication. Subjects who meet eligibility criteria will be randomized to receive a single dose of either placebo, 5 × 109 ciu/limb of DVC1-0101, or 1 × 109 ciu/limb of DVC1-0101 administered by direct intramuscular injection. The participation length in this trial for subjects will be approximately 12 months with nine visits. The primary endpoints are to evaluate the efficacy of DVC1-0101 versus placebo on peak walking time, and to evaluate the safety and tolerability of two dosage levels of DVC1-0101. The secondary endpoints are 1) to evaluate the effect of DVC1-0101 on claudication onset time, measured by a treadmill test and quality of life, measured using the Walking Impairment Questionnaire, 2) to determine the effect of DVC1-0101 on qualifying limb hemodynamics, and 3) to explore the pharmacodynamics of DVC1-0101 by evaluating biomarkers. 1.3. Discussion: The results of this trial will provide insights into the potential of DVC1-0101 for improving walking activities. The results will also help with the design of a possible phase III study.

Semi‐Allogeneic Dendritic Cells Injected via the Intratumoural Injection Route Show Efficient Antitumour Effects in Cooperation with Host‐Derived Professional Antigen‐Presenting Cells

Dendritic cells (DC)‐based immunotherapy is a potent anticancer modality. In DC‐based immunotherapy, allogeneic DC may be an alternative source, but the usefulness of allogeneic DC in DC‐based immunotherapy is still controversial. When used for immunotherapy, three factors may affect the efficiency of an allogeneic DC‐driven antitumour response: (1) survival time, which is affected by T‐cell alloresponses; (2) major histocompatibility complex incompatibility with the host cells in the context of antigen presentation; and (3) the role of host‐derived professional antigen‐presenting cells (pAPC). In addition, it is unclear which injection route is preferable when using allogeneic DC. In this study, we demonstrate that semi‐allogeneic DC, which share half of the genes of the recipient, are more effective when used via the intratumoural (i.t.) injection route, rather than the subcutaneous (s.c.) injection route, for the induction of efficient antitumour effects and the generation of a significant tumour‐specific CD8+ T‐cell response. The i.t. route has the advantage of not requiring ex vivo pulsation with tumour lysates or tumour antigens, because the i.t.‐injected DC can engulf tumour antigens in situ. Allogeneic bone marrow transplantation (BMT) models, which permit us to separately assess the three factors described previously, show that while all three factors are important for efficient antitumour effects, the control of the alloresponse to injected DC is the most crucial for host‐derived pAPC to function well when DC are administered intratumourally. This information may be useful for DC‐based cancer immunotherapy under circumstances that do not allow for the use of autologous DC.