Phase I Trial of “bi-shRNAifurin/GMCSF DNA/Autologous Tumor Cell” Vaccine (FANG) in Advanced Cancer

Abstract

We performed a phase I trial of FANG vaccine, an autologous tumor-based product incorporating a plasmid encoding granulocyte-macrophage colony-stimulating factor (GMCSF) and a novel bifunctional short hairpin RNAi (bi-shRNAi) targeting furin convertase, thereby downregulating endogenous immunosuppressive transforming growth factors (TGF) β1 and β2. Patients with advanced cancer received up to 12 monthly intradermal injections of FANG vaccine (1 × 10(7) or 2.5 × 10(7) cells/ml injection). GMCSF, TGFβ1, TGFβ2, and furin proteins were quantified by enzyme-linked immunosorbent assay (ELISA). Safety and response were monitored. Vaccine manufacturing was successful in 42 of 46 patients of whom 27 received ≥1 vaccine. There were no treatment-related serious adverse events. Most common grade 1, 2 adverse events included local induration (n = 14) and local erythema (n = 11) at injection site. Post-transfection mean product expression GMCSF increased from 7.3 to 1,108 pg/10(6) cells/ml. Mean TGFβ1 and β2 effective target knockdown was 93.5 and 92.5% from baseline, respectively. Positive enzyme-linked immunospot (ELISPOT) response at month 4 was demonstrated in 9 of 18 patients serially assessed and correlated with survival duration from time of treatment (P = 0.025). Neither dose-adverse event nor dose-response relationship was noted. In conclusion, FANG vaccine was safe and elicited an immune response correlating with prolonged survival. Phase II assessment is justified.

Summary of bi-shRNA^furin/GM-CSF Augmented Autologous Tumor Cell Immunotherapy (FANG™) in Advanced Cancer of the Liver

“…The construction and cGMP manufacturing of the FANG immunotherapy have been described [27,30]. Briefly, the FANG vector utilizes the pUMVC3 vector backbone in which the GM-CSF encoding cDNA and the DNA encoding the bi-shRNA furin are under transcriptional control of the cytomegalovirus immediate early promoter of the expression vector.…”

“…Recently, we have published evidence of immune induction, safety, and clinical benefit in advanced solid tumor cancer patients who received FANG™ immunotherapy [27]. FANG is a unique, triplex [17], autologous tumor cell immunotherapy, which provides three immune modulatory components: (1) an autologous whole-cell complex providing a tumor-specific full antigen matrix, (2) immune activation via local-regional GM-CSF protein expression, and (3) inhibition of TGFβ 1 and TGFβ 2 expression through knockdown of the proprotein convertase furin, utilizing a novel bifunctional small hairpin RNA interference (bi-shRNAi) technology [28].…”

PDX1 associated therapy in translational medicine

“…Conventional siRNA generated from double-stranded RNA molecules can bind target RNA sequences and interfere with their translation or target them for destruction (17). Having demonstrated PDX1 is a potential gene target for PDAC, we developed our first therapeutic platform targeting PDX1 using a novel RNAi technology bi-functional shRNA (11,18,19). The bifunctional shRNA consists of two stem-loop shRNA (shorthairpin RNA) structures: one cleavage-dependent unit with a perfectly matched passenger-strand and guide-strand, and one cleavage-independent unit composed of a mismatched double strand.…”

Cancer targeting vaccines: Surrogate measures of activity

“…Knockdown of the direct target (furin) and the key downstream effector targets (TGFβ1, TGFβ2) was effective (Table 3). 8 Moreover, dual functions of GMCSF expression and knockdown of both TGFβ1 and TGFβ2 proteins were consistent and within predicted guidelines when expressed. No significant toxic effect was observed and suggested survival advantage was demonstrated between later stage patients receiving FANG and those electing to choose other standard of care options (Fig.…”