Intratumoral injection

It is quite possible that a treatment may be initiated using, for example, intratumoral injections to deliver a gene, which may subsequently be administered systemically. As a considerable amount of relevant information will have already been generated to support the intratumoral route, this would be another case for doing bridging studies. Comparative distribution studies will help to identify how much more safety evaluation may be required. 

In the case of local administration, lipoplexes are generally retained at the site of injection, with poor dispersion (22). In contrast to small emulsions or neutral liposomes, which immediately appear in the venous outflow perfusate following intratumoral injection, the appearance of cationic liposomes is highly restricted to the injection zone (22). The authors deduced that the determining factor altering the pharmacokinetic properties is not the rate of transfer from the interstitial space to the vascular site but rather the rate of transfer from the injection site to the well-vascularized region (23). 

Nomura T, et al. Effect of particle size and charge on the disposition of lipid carriers after intratumoral injection into tissue-isolated tumors. Pharm Res 1998 15 128. 

Heise CC, Williams A, Olesch J, et al. Efficacy of a replication-competent adenovirus (ONYX-015) following intratumoral injection intratumoral spread and distribution effects. Cancer Gene Ther 1999 6 499-504. 

Yen N, Ioannides CG, Xu K, et al. Cellular and humoral immune responses to adenovirus and p53 protein antigens in patients following intratumor injection of an adenovirus vector expressing wild-type p53 (Ad-p53). Cancer Gene Ther 2000 7 530-536. 

Yang, J.P., and L. Huang, Direct gene transfer to mouse melanoma by intratumor injection of free DNA. Gene Ther., 1996. 3 542-8. 

Cunningham C, Nemunaitis J. A phase I trial of genetically modified Salmonella typhimurium expressing cytosine deaminase (TAPET-CD, VNP20029) administered by intratumoral injection in combination with 5-fluorocytosine for patients with advanced or metastatic cancer. Human Gene Ther 2001 12(12) 1594—1596. 

Tumor tissue has also been demonstrated to take up naked pDNA following direct intratumoral injection, but this ability may be dependent on tumor type and the pDNA construct. In an important study by Vile and Hart (1993), mice bearing subcutaneous (s.c.) B16F1 melanoma or Colo 26 colon carcinoma were injected intratumorally with naked P -gal pDNA or P -gal pDNA/calcium phosphate precipitates. The tumors were collected on days 2, 4, 6 and 10 after the pDNA intratumoral injection. A gradual increase in blue-staining cells was found in the transfected melanomas with 10-15% of the cells expressing /3-gal by day ten. In contrast, none of the colon carcinoma tumors was positive for /3-gal. One explanation for the lack of in vivo transfection of the colon carcinoma is that the /3-gal pDNA constmcts contained melanoma-specific promoters (tyrosinase and TRP promoters). This study demonstrated that using an appropriate promoter established tumors could take up and express naked pDNA. 

In a similar study by Yang and Huang (1996), melanoma tumors in mice were in vivo transfected by the direct intratumoral administration of naked pDNA, resulting in reporter gene expression for up to ten days. In another study, Walker 256 carcinoma tumors in rats were found to express CAT after intratumoral injection of naked pDNA encoding CAT (Nomura et al., 1997). More recently electroporation has been used to deliver naked pDNA to tumors (described further in the following section). 

Furthermore, a single intratumoral injection of IL-12 pDNA followed by electroporation resulted in a significant inhibition of tumor growth as well as a reduction in the growth of a distant tumor. Tumors treated with IL-12 pDNA and electroporation were infiltrated with NK cells and CD3+ T cells and a tumor-specific CTL response was generated. 

Figure 19.7 Pharmacokinetic model for analyzing drug disposition following direct intratumoral injection. ku rate constant of transfer from poorly perfused region to well perfused region k2, venous appearance rate constant k2, rate constant of leakage from the surface A, and X2, drug amounts in well perfused and poorly perfused regions, respectively.

Saikawa, A., Nomura, T., Yamashita, F., Takakura, Y., Sezaki, H. and Hashida, M. (1996) Pharmacokinetic analysis of drug disposition after intratumoral injection in a tissue-isolated tumor perfusion system. Pharm. Res., 13, 1438-1444. 

Vile, R.G. and Hart, I.R. (1993) Use of tissue-specific expression of the herpes simplex virus thymidine kinase gene to inhibit growth of established murine melanomas following direct intratumoral injection of DNA. Cancer Res., 53, 3860-3864. 

Pharmacokinetic parameters, kx and k2, following direct intratumoral injection of drags in 393... 

Hamstra DA, Moffat BA, Hall DE, et al. Intratumoral injection of BCNU in ethanol (DTI-015) results in enhanced delivery to tumor—a pharmacokinetic study. JNeurooncol. 2005 73 225-238. 

Azemar M, Djahansouzi S. Regression of cutaneous tumor lesions in patients intratumorally injected with a recombinant single-chain antibody-toxin targeted to ErbB2/HER2. Breast Cancer Res Treat 2003 82 155-64. 

Although the efficiency of transfection was 18.6% in vivo after intratumoral injection of DNA liposomal complexes, the sensitivity to ganciclovir was improved as tumor weight induction was observed. In 2001, the FDA approved a clinical protocol relevant to liposomal gene therapy with the HSVtk/GCV system for the treatment of glioblastoma multiforme [408],... 

Although direct toxic effects of natural interferon beta on the nervous system have been regarded as a possible risk of intraventricular and/or intratumoral injection (14), interferon beta is considered to be markedly less neurotoxic than interferon alfa (15). 

---