Continuous intra-arterial administration of recombinant interleukin-2 in low-stage bladder cancer. A phase IB study

Bladder Cancer Immunotherapy: BCG and Beyond

Mycobacterium bovis bacillus Calmette-Guérin (BCG) has become the predominant conservative treatment for nonmuscle invasive bladder cancer. Its mechanism of action continues to be defined but has been shown to involve a T helper type 1 (Th1) immunomodulatory response. While BCG treatment is the current standard of care, a significant proportion of patients fails or do not tolerate treatment. Therefore, many efforts have been made to identify other intravesical and immunomodulating therapeutics to use alone or in conjunction with BCG. This paper reviews the progress of basic science and clinical experience with several immunotherapeutic agents including IFN-α, IL-2, IL-12, and IL-10.

Immunotherapy of urologic tumors: principles and progress

Immunotherapy is receiving interest as an alternative or adjuvant approach to the treatment of many malignancies. The potential for immune modulation as a treatment of solid tumors is the focus of cancer researchers throughout the world. Though not a novel idea, increasing technological sophistication and continued advancement in the understanding of the immune system have increased the number of novel therapeutic approaches. In urology, BCG is an excellent example of how modulation of the immune system can be used to treat malignancy, and we are only now beginning to understand its immune mechanisms. Numerous other immunotherapeutic approaches have been and are being developed and evaluated. We provide a brief overview of immunology and its relation to tumor development and growth, and focus on some of the immunotherapeutic approaches to renal cell carcinoma, prostate adenocarcinoma, and transitional cell carcinoma of the bladder.

Interleukin-2 gene transfer into human transitional cell carcinoma of the urinary bladder

Transitional cell carcinoma of the bladder is one of the human cancers most responsive to immunotherapy, and local interleukin-2 (IL-2) production appears to be an important requirement for immunotherapy to be effective. In this study, we engineered two human bladder cancer cell lines (RT112 and EJ) to constitutively release human IL-2 by retroviral vector-mediated gene transfer. Following infection and selection, stable and consistent production of biologically active IL-2 was demonstrated at both the mRNA and the protein level. Morphology, in vitro growth rate and proliferation, as well as other cytokine gene mRNA or membrane adhesion receptor expression, were not altered in IL-2 transduced cells as compared to their parental or control vector-infected counterparts. Moreover, IL-2 engineered cells lost their tumorigenicity into nu/nu mice and the mechanism of rejection appeared to involve multiple host effector cell populations, among which a prominent role was played by neutrophils and radiosensitive cells. These findings may offer support to the development of an IL-2-based gene therapy approach to human bladder cancer.

Cytokine gene modification of bladder cancer cells for the establishment of bladder cancer vaccine

A bladder tumor vaccine in mouse models was established by introducing interleukin-2 (IL-2) gene into mouse bladder cancer cells (MBT-2). Mice injected with non-modified MBT-2 cells did not reject subsequent challenge of MBT-2 cells. Mice injected with IL-2-gene-modified MBT-2 cells (MBT-2/IL-2) rejected subsequent challenge of unmodified MBT-2 cells but not 38C13 cells, which have the same genetic background but different antigenicity. According to these results, an injection of MBT-2/II.-2 can establish specific immunity against parental MBT-2 cells in mice, which is also demonstrated by cytotoxic T lymphocytes assay. Vaccinations with MBT-2/IL-2 cured 60% of bladder cancer which had been pre-established in mice. These results suggest that tumor cells genetically modified with IL-2 gene can act as a tumor vaccine which is expected to be a new method for immunotherapy of cancers.

Bacillus Calmette-Guérin sensitises fresh transitional carcinoma cells and T24 cell line to non-MHC-restricted cytotoxicity in vitro

The activity of lymphokine (interleukin-2) activated killer (LAK) cells from 9 patients with transitional cell carcinoma (TCC) was tested against autologous, freshly purified transitional carcinoma cells. Cytotoxicity was relatively low. Bacillus Calmette-Guérin (BCG) substantially augmented both LAK activity and the cytolytic activity of non-stimulated peripheral blood mononuclear cells (PBMC) against autologous TCC when tested with 6 additional TCC patients. A similar enhancing effect of BCG was noted with leucocytes obtained from normal donors when tested against an allogenic T24 cell line. Both natural killer (NK) cells and T cells appeared to be responsible for the increased cytolytic activity caused by BCG. No cytolytic activity was noted against normal transitional epithelial cells. Sensitisation of TCC cells to the immune system may explain the clinical effects of BCG.

Treatment of transitional cell carcinoma of the bladder with intravesical interleukin-2: a pilot study

Human recombinant interleukin-2 (rIL-2) administered systemically can mediate the regression of solid tumors in some patients. IL-2 has been detected in the bladder effluent from patients treated with intravesical BCG for transitional cell carcinoma of the bladder (TCC), suggesting that IL-2 may be an effector molecule in the mechanism of action of BCG. The purpose of the pilot study was to determine the response rate, duration of response and toxicity of rIL-2 (Cetus) administered intravesically to previously untreated patients and patients who had failed prior intravesical therapy with other agents. Fourteen patients with biopsy proven transitional cell carcinoma (13 Stage TIS/Ta/T1, 1 Stage T2) were treated with 8 weekly instillations of 12 x 10(6) IU of rIL-2. An index lesion was followed with cystoscopy, biopsy and cytology at three months, with identical follow up every three months thereafter if a response was noted in the index lesion at the first evaluation. There were 3 complete responses (duration of response measured from start of treatment to date of progression) of 9+, 3, 9 months; one patient with TIS, and 2 patients with Ta disease. There were 11 non-responders for an overall response rate of 21%. One patient with extensive CIS had a dramatic partial response and was converted to a complete response with a second 8-week course of rIL-2. All of the complete responders had failed prior intravesical therapy with standard agents. Toxicity from rIL-2 given intravesically was minimal. One patient reported malaise for 24 hours after each treatment and two patients developed asymptomatic lower UTIs.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytokines in tumour therapy

Cytokines are low molecular weight proteins released by cells of the immune system that have therapeutic potential in cancer. They include the interleukins, the interferons, tumour necrosis factor and the colony-stimulating factors. Cytokines are capable of producing significant and sustained responses against a number of tumours. Clinically, the highest response rates to cytokine immunotherapy have been seen in melanoma and renal cell cancer. Current efforts aim to reduce treatment-related toxicity while maintaining the efficacy of cytokines. The therapeutic potential of these agents may be increased with genetic manipulation by introducing genes encoding cytokines into tumour-infiltrating lymphocytes and certain tumour cells. However, immunotherapy remains time consuming and expensive, and further developments are necessary before it can have a definitive role in tumour management.