TNFerade Biologic: Preclinical toxicology of a novel adenovector with a radiation-inducible promoter, carrying the human tumor necrosis factor alpha gene

Abstract

TNFerade Biologic ( TNFerade ) is a second -generation ( E1 -, E3 -, and E4 -deleted ) replication -deficient adenovector carrying the transgene encoding for human tumor necrosis factor alpha ( TNFa ), regulated by the radiation -sensitive promoter Early Growth Response ( Egr -1 ). We hypothesized that intratumoral injection of TNFerade followed by radiation would result in potentially therapeutic levels of TNFa with minimal toxicity. Three preclinical studies were conducted, the purpose of which was to characterize the toxicity and pharmacokinetics of TNFerade in conjunction with radiation in nude as well as immune -competent ( Balb / c ) mice. A total of 80 mice in the nude mouse toxicology study, all bearing human squamous cell carcinoma xenografts, 120 mice in the Balb / c study, and 33 nude mice in the pharmacokinetic study were used. Doses ranging from 4Â10 9 to 4Â10 10 particle units (pu ) (4Â10 11 pu in the Balb / c study ) were explored, with and without radiation. In the nude mice studies, TNFerade was injected intratumorally, whereas in the Balb / c study, TNFerade was administered by subcutaneous injection. TNFerade was well tolerated. In the nude mice studies, no significant toxicity occurred in any dose group. In the Balb / c study, 6 / 40 mice at the top dose (4Â10 11 pu ) were sacrificed in moribund condition ( 5 / 20 in the TNFerade + radiation group, 1 / 20 in the TNFerade alone group ).Necropsy showed local necrosis and ulceration at the site of the injection. No deaths or significant toxicity were observed at the lower dose levels ( 4Â10 9 and 4Â10 10 pu ), indicating a large safety margin for initial studies in humans. The pharmacokinetic study demonstrated high sustained levels of TNFa in the tumor homogenate with no ''spillover'' to plasma, where TNFa levels were below the level of detection. Radiation increased intratumoral levels of TNFa by a factor of 12 ( from 0.998 to 11.55 ng / g ). In conclusion, a gene therapy approach with TNFerade, in combination with radiation, represents a potential way to utilize the potent anticancer activity of TNFa without systemic toxicity.

Resveratrol is an effective inducer of CArG-driven TNF-α gene therapy

“…[5][6][7][8][9] This cancer gene therapy is currently in phase I, II and III trials and demonstrates synergistic antitumor effects with anticancer agents. 10,11 However, not all cancer patients who might benefit from TNFerade can tolerate radiation and/or chemotherapy, suggesting that a nontoxic inducer of CArG elements may be clinically useful in some patients.…”

Safety and biodistribution studies of an HSV multigene vector following intracranial delivery to non-human primates

“…Previous studies by us and others have shown that local TNFa production provides multiple benefits to cancer gene therapy and include the recruitment of nonspecific antitumor cellular responses and increased the effectiveness of radiation therapy and GKR. [20][21][22] The expression of TNFa was vigorous during the initial phase of the study and rapidly declined to undetectable levels at 4 weeks postinoculation as documented by RT-PCR. We did not determine whether increased levels of TNF were present in the blood; however, the injected animals showed no behavioral changes or weight loss.…”

“…In preclinical toxicology studies in rodents using an adenoviral vector that expresses TNFa (TNFerSafety testing of an HSV multigene vector D Wolfe et al ade), a decrease in hemoglobin (B19%) and increases in platelets (B100%) and white blood cells (300%) was documented. 21 In the TNFerade study, however, high doses of vector were repeatedly injected subcutaneously and lead to ulceration and necrosis at the injection site, while our study involved a single intracranial injection time point. Unlike the TNFerade vector, our vector did not induce any significant changes in animal weight or in the WBC differentials.…”

“…The synergistic effect of radiation and TNFa on a variety of tumors provides an additional combinatorial approach to increasing the effectiveness of experimental therapies. [17][18][19] Chung et al, 20 Rasmussen et al, 21 and Staba et al 22 found inducible TNF expression (TNFerade) combined with radiation was superior to either treatment alone. Similarly, the response to GKR was enhanced by sensitizing experimental tumors with vector-expressed TNFa using our HSV vector system in combination with GKR.…”

Radiation improves gene delivery by a novel transferrin-lipoplex nanoparticle selectively in cancer cells

“…One of such advance is TNFerade, which uses radiation to induce tumor necrosis factor-a expression spatially and temporally in tumors by replication-deficient adenovirus vector containing a radiation-inducible promoter from the egr-1 gene. 14,15 Our own study has demonstrated that radiation induces adenovirus uptake in tumors, contributing to enhanced transgene expression. 16,17 For liposome-mediated delivery, radiation has been shown to increase drug delivery to tumor blood vessels 18 and to sustain an enhanced transgene expression in human breast cancer cells.…”