A Phase 2, International, Multicenter, Open-label Clinical Trial of Subcutaneous Tbo-Filgrastim in Pediatric Patients With Solid Tumors Undergoing Myelosuppressive Chemotherapy.

This phase 2, multicenter, open-label trial investigated the safety and tolerability of tbo-filgrastim in pediatric patients receiving myelosuppressive chemotherapy. In total, 50 patients 1 month to below 16 years of age with solid tumors without bone marrow involvement were stratified into 3 age groups (2 infants, 30 children, 18 adolescents) and prophylactically administered tbo-filgrastim 5 µg/kg body weight once daily subcutaneously. The administration started after the last chemotherapy treatment in week 1 of the first cycle and continued until the expected neutrophil nadir had passed, and the neutrophil count had recovered to 2.0×10/L. The primary endpoint was safety and tolerability of tbo-filgrastim; secondary endpoints included efficacy. The mean (SD) number of doses administered was 9.2 (2.83) in children and 7.3 (1.88) in adolescents. Serious treatment-emergent adverse events were reported in 24% of patients; the most common were febrile neutropenia (FN) (12%), anemia (8%), and thrombocytopenia (8%). Nine patients (18%) experienced mild treatment-related treatment-emergent adverse events; the most common were musculoskeletal and connective tissue disorders (8%). No deaths or withdrawals occurred. The incidence of severe neutropenia (SN) was 52% and the mean (SD) duration of SN was 1.8 (2.21) days; FN incidence was 26%. A daily dose of tbo-filgrastim 5 µg/kg body weight administered to pediatric patients demonstrated a safety profile consistent with the safety profile in adult patients. The incidence of FN was on the lower end of the range reported in the literature and the SN results provide supportive data on the efficacy of tbo-filgrastim in pediatric patients.

Immunogenicity assessment of tbo-filgrastim in cancer patients receiving chemotherapy.

AIM: This integrated analysis examined the immunogenicity of tbo-filgrastim and its potential clinical impact in three Phase III randomized studies in patients with breast cancer, lung cancer and non-Hodgkin lymphoma receiving chemotherapy. RESULTS: Treatment-emergent antidrug antibodies (ADA) occurred in 3/213 (1.4%) breast cancer patients, 2/160 (1.3%) lung cancer patients and 1/63 (1.6%) patients with non-Hodgkin lymphoma. None of the treatment-emergent ADA showed cross-reactivity toward native granulocyte-colony stimulating factors or exhibited neutralizing activity against tbo-filgrastim. Among patients with treatment-emergent ADA, there was no treatment-related hypersensitivity or anaphylaxis and no evidence of loss of clinical efficacy. CONCLUSION: Tbo-filgrastim has demonstrated low immunogenicity in cancer patients receiving chemotherapy and ADA response does not impact safety and efficacy in the patients.

Immunogenicity Assessment of Lipegfilgrastim in Patients with Breast Cancer Receiving Chemotherapy.

Lipegfilgrastim is a long-acting, once-per-cycle, glycopegylated recombinant granulocyte colony-stimulating factor (G-CSF) used to prevent neutropenia in patients receiving myelosuppressive chemotherapy. This integrated analysis examined the immunogenicity of lipegfilgrastim and its potential clinical impact in two double-blind randomized studies (phases II and III) of patients with breast cancer receiving chemotherapy. Serum samples were analyzed using sequential assays for screening, confirmation, antibody titer, and characterization of antidrug antibodies (ADA). Neutropenia-related efficacy measures were reviewed for each ADA-positive patient. Among 255 patients receiving lipegfilgrastim (154 in phase II, 101 in phase III) and 155 patients receiving pegfilgrastim (54 in phase II, 101 in phase III), the incidence of treatment-emergent ADA was low and similar between the lipegfilgrastim (phase II: 1.3%; phase III: 1.0%) and pegfilgrastim (phase II: 1.9%; phase III: 1.0%) arms. None of the treatment-emergent ADA-positive samples exhibited neutralizing activity against lipegfilgrastim, pegfilgrastim, or glycosylated G-CSF in a cell-based neutralizing antibody assay. No changes were observed in neutropenia-related efficacy measures among ADA-positive patients, and no treatment-related hypersensitivity or anaphylaxis occurred. These results indicate that there is no apparent impact of ADA on lipegfilgrastim efficacy and safety.

Protective effects of bone marrow stromal cell transplantation in injured rodent brain: synthesis of neurotrophic factors.

Several groups have suggested that transplantation of marrow stromal cells (MSCs) promotes functional recovery in animal models of brain trauma. Recent studies indicate that tissue replacement by this method may not be the main source of therapeutic benefit, as transplanted MSCs have only limited ability to replace injured central nervous system (CNS) tissue. To gain insight into the mechanisms responsible for such effects, we systematically investigated the therapeutic potential of MSCs for treatment of brain injury. Using in vitro studies, we detected the synthesis of various growth factors, including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), and neurotrophin-3 (NT-3). Enzyme-linked immunosorbent assay (ELISA) demonstrated that MSCs cultured in Dulbecco's modified Eagle medium (DMEM) produced substantial amounts of NGF for at least 7 weeks, whereas the levels of BDNF, GDNF and NT-3 remained unchanged. In studies in mice, after intraventricular injection of MSCs, NGF levels were increased significantly in cerebrospinal fluid by ELISA, confirming our cell culture results. Further studies showed that treatment of traumatic brain injury with MSCs could attenuate the loss of cholinergic neuronal immunostaining in the medial septum of mice. These studies demonstrate for the first time that by increasing the brain concentration of NGF, intraventricularly transplanted MSCs might play an important role in the treatment of traumatic brain injury.

Reduced inflammatory reactions to the inoculation of helper-dependent adenoviral vectors in traumatically injured rat brain.

Traumatic brain injury (TBI) causes delayed neuronal deficits that in principle could be prevented by timely intervention with therapeutic genes. However, appropriate vectors for gene transfer to the brain with TBI remain to be developed. First-generation adenoviruses (fgAd) are usually associated with inflammatory and toxic effects when inoculated into brains, despite their high efficiency of gene transfer to these tissues. In this study the authors attempted to determine whether a less immunogenic gene-transfer protocol can be established in the traumatically injured rat brain using helper-dependent adenoviruses (hdAd), a novel adenoviral construct with full deletion of viral coding sequences. Their results show that transgene expression from intrahippocampally inoculated hdAd is maintained for at least 2 months after TBI, in contrast to the much shorter duration of fgAd-mediated gene expression. There was only minimal secretion of proinflammatory IL-1beta and TNF-alpha after inoculation of hdAd. Furthermore, the hdAd-mediated gene expression was associated with less microglial proliferation, astrocytic activation, and macrophage infiltration than observed in fgAd-inoculated brains. There was no additional tissue loss after hdAd inoculation compared with PBS injection. Although both anti-adenoviral and neutralizing antibodies were found in serum after brain inoculation of hdAd, they did not appear to affect transgene expression. The results suggest that hdAd are less immunogenic vectors than conventional adenoviral vectors, and offer improved vehicles for long-term therapeutic transgene transfer to traumatically injured brains.

Improvement of spatial learning and memory after adenovirus-mediated transfer of the nerve growth factor gene to aged rat brain.

Adenovirus-mediated transfer of the nerve growth factor gene promotes significant recovery of age-related cholinergic neuronal deficits in aged rats, but the effects of such treatment on cognitive dysfunction remain unclear. Herein we report a beneficial effect of first-generation adenovirus-mediated nerve growth factor gene transfer (AdNGF) on the spatial learning and memory of aged rats. The NGF protein was detected by enzyme-linked immunosorbent assay in cerebrospinal fluid as early as 3 days after gene transfer and was expressed for at least 30 days. Escape latency in the Morris water maze hidden-platform test was significantly improved on day 8 postinoculation in memory-impaired rats treated with AdNGF as well as at later testing intervals. Ultimately, the escape latency values for the AdNGF group become indistinguishable from those for aged rats with normal learning capacity. Immunohistochemical analysis of septal cholinergic neurons for choline acetyltransferase (ChAT) showed significant increases in both the number and somal distribution of ChAT-positive cells after inoculation of memory-impaired rats with AdNGF. Improvement in memory performance was positively correlated with increases in both NGF concentration in cerebrospinal fluid (r = 0.73, p = 0.005) and the number of ChAT-staining cells (r = 0.77, p = 0.0022). We conclude that AdNGF can improve cognitive function in memory-impaired aged rats and, with refinements in vector-driven expression of the transgene, may prove suitable for use in humans.