INTRAVESICAL INTERLEUKIN-2 IN T1 PAPILLARY BLADDER CARCINOMA: REGRESSION OF MARKER LESION IN 8 OF 10 PATIENTS

Systemic and intravesical adoptive cell therapy of tumor-reactive T cells can decrease bladder tumor growth in vivo

BACKGROUND

The therapeutic armamentarium of bladder cancer has been recently enriched with the introduction of new therapies including immune checkpoint inhibitors, receptor tyrosine kinase inhibitors and antibody drug conjugates, however treatment responses and duration of responses are still less than expected. Adoptive cellular therapy (ACT) using tumor-infiltrating lymphocytes (TILs) has potential to treat bladder cancer, as previously demonstrated by successful expansion of tumor reactive T cells from human bladder tumors.

METHODS

A model system using OT-I T cells and an ovalbumin expressing MB49 tumor cell line (MB49OVA) was developed to study ACT in bladder cancer. Systemic ACT-treated mice were given T cells intravenously after lymphodepleting chemotherapy and followed by interleukin (IL)-2 administration. Intravesical ACT treated mice were given T cells directly into the bladder, without chemotherapy or IL-2. TILs were isolated from MB49 orthotopic tumors and expanded ex vivo in IL-2. Immune cell infiltrates were analyzed by flow cytometry. T cell infiltration was studied using a CXCR3 blocking antibody.

RESULTS

Systemic ACT-treated mice had a decrease in tumor growth, increase in T cell infiltration and long-term immune protection compared with control-treated mice. OT-I T cells delivered intravesically were able to control tumor growth without lymphodepleting chemotherapy or IL-2 in MB49OVA orthotopic tumors. Intravesical delivery of TIL expanded from MB49 tumors was also able to decrease tumor growth in mice with MB49 orthotopic tumors. Blocking CXCR3 on OT-I T cells prior to intravesical delivery decreased T cell infiltration into the tumor and prevented the control of tumor growth.

CONCLUSIONS

This study demonstrates how TIL therapy can be used in treating different stages of bladder cancer.

The Impact of a New Interleukin-2-Based Immunotherapy Candidate on Urothelial Cells to Support Use for Intravesical Drug Delivery

(1) Background: The intravesical instillation of interleukin-2 (IL-2) has been shown to be very well tolerated and promising in patients with bladder malignancies. This study aims to confirm the use of a new IL-2 containing immunotherapy candidate as safe for intravesical application. IL-2, produced in mammalian cells, is glycosylated, because of its unique solubility and stability optimized for intravesical use. (2) Materials and Methods: Urothelial cells and fibroblasts were generated out of porcine bladder and cultured until they reached second passage. Afterwards, they were cultivated in renal epithelial medium (REM) and Dulbecco’s modified Eagles medium (DMEM) with the IL-2 candidate (IMS-Research) and three more types of human interleukin-2 immunotherapy products (IMS-Pure, Natural IL-2, Aldesleukin) in four different concentrations (100, 250, 500, 1000 IU/mL). Cell proliferation was analyzed by water soluble tetrazolium (WST) proliferation assay after 0, 3, and 6 days for single cell culture and co-culture. (3) Results: Proliferation assays showed that all IL-2 products induced very similar cultivation results and none of the IL-2 variants had a negative impact on the proliferation of urothelial cells and fibroblast in either concentration. (4) Conclusion: Human recombinant glycosylated IL-2 as well as human non-glycosylated IL-2 have no negative influence on the tissue cell proliferation of porcine urothelial cells and fibroblasts in vitro and represent a promising and innovative potential intravesical therapy candidate for patients in high need.

Elucidating the Immune-Related Mechanisms by Which Probiotic Strain Lactobacillus casei BL23 Displays Anti-tumoral Properties

We have recently described antitumor properties of Lactobacillus casei BL23 strain in both a mouse allograft model of human papilloma virus (HPV)-induced cancer and dimethylhydrazine-associated colorectal cancer. However, the mechanisms underlying these beneficial effects are still unknown. Interestingly, in vitro cellular models show that this bacterium is able to stimulate the production of high levels of IL-2. Because this cytokine has well-known antitumor properties, we decided to explore its role in the anti-cancer effects of BL23 using the HPV-induced cancer model. We found a negative correlation between IL-2 and tumor size confirming the necessity of IL-2 to protect from tumor development. Then, we blocked IL-2 synthesis using neutralizing monoclonal antibodies in mice that were challenged with lethal levels of tumor cells; this led to a significant reduction in the protective abilities of BL23. Next, we used a genetically modified strain of Lactococcus lactis to deliver exogenous IL-2 to the system, and in doing so, we were able to partially mimic the antitumor properties of BL23. Additionally, we showed the systemic role of T-cells in tumor protection through a negative correlation between tumor size and T-cells subpopulations and an increasement of BL23-specific local Foxp3 levels in tumor-bearing mice. Finally, we observed a negative correlation between tumor size and NK+ cells, but local recruitment of NK cells and cytotoxic activity appeared specific to BL23 treatment. Taken together, our data suggest that IL-2 signaling pathway plays an important role in the anti-tumoral effects of probiotic strain L. casei BL23. These results encourage further investigation in the use of probiotic strains for potential therapeutic applications to clinical practice, in particular for the treatment of colorectal cancer. Furthermore, our approach could be extended and applied to other potential beneficial microorganisms, such as gut microbiota, in order to better understand the crosstalk between microbes and the host.

Quadruple immunotherapy of Bacillus Calmette-Guérin, interferon, interleukin-2, and granulocyte-macrophage colony-stimulating factor as salvage therapy for non-muscle-invasive bladder cancer

BACKGROUND

Bacillus Calmette-Guérin (BCG) is the most effective initial intravesical therapy for high-grade non-muscle invasive bladder cancer, but many patients still fail. Combination intravesical BCG and interferon (IFN) will salvage some patients but results remain suboptimal.

OBJECTIVE

We hypothesized that further immunostimulation with intravesical interleukin-2 and subcutaneous granulocyte-macrophage colony-stimulating factor may improve response to intravesical BCG and IFN in patient with prior BCG failure(s).

METHODS

A retrospective review was performed. Patients received 6 treatments of quadruple immunotherapy (intravesical solution with one-third dose BCG, 50 million units IFN, and 22 million units interleukin-2, along with a 250-mcg subcutaneous sargramostim injection). Surveillance began 4 to 6 weeks after treatment completion. Patients received maintenance if recurrence-free. Success was defined as no recurrence (bladder or extravesical) and bladder preservation. Analysis was performed by Kaplan-Meier method (P<0.05).

RESULTS

Fifty-two patients received treatment with a median recurrence follow-up of 16.3 months and overall follow-up of 41.8 months. All patients had at least 1 prior BCG failure and 13% had 2 or more prior failures. Only 3 patients (6%) were unable to tolerate full induction. Treatment success was 55% at 1 year, and 53% at 2 years. Thirteen patients (25%) underwent cystectomy at a median time of 17.3 months with disease progression to T2 in 1 patient and T3 in 2 patients. No patients had positive surgical margins or positive lymph nodes.

CONCLUSIONS

In patients with non-muscle-invasive bladder cancer with prior BCG failure, quadruple immunotherapy demonstrated good treatment success in some patients and warrants further evaluation.

Improving Bacillus Calmette-Guérin (BCG) immunotherapy for bladder cancer by adding interleukin 2 (IL-2): a mathematical model

One of the treatments offered to non-invasive bladder cancer patients is BCG instillations, using a well-established, time-honoured protocol. Some of the patients, however, do not respond to this protocol. To examine possible changes in the protocol, we provide a platform for in silico testing of alternative protocols for BCG instillations and combinations with IL-2, to be used by urologists in planning new treatment strategies for subpopulations of bladder cancer patients who may benefit from a personalized protocol. We use a systems biology approach to describe the BCG-tumour-immune interplay and translate it into a set of mathematical differential equations. The variables of the equation set are the number of tumour cells, bacteria cells, immune cells, and cytokines participating in the tumour-immune response. Relevant parameters that describe the system's dynamics are taken from a variety of independent literature, unrelated to the clinical trial results assessed by the model predictions. Model simulations use a clinically relevant range of initial tumour sizes (tumour volume) and tumour growth rates (tumour grade), representative of a virtual population of fifty patients. Our model successfully retrieved previous clinical results for BCG induction treatment and BCG maintenance therapy with a complete response (CR) rate of 82%. Furthermore, we designed alternative maintenance protocols, using IL-2 combinations with BCG, which improved success rates up to 86% and 100% of the patients, albeit without considering possible side effects. We have shown our simulation platform to be reliable by demonstrating its ability to retrieve published clinical trial results. We used this platform to predict the outcome of treatment combinations. Our results suggest that the subpopulation of non-responsive patients may benefit from an intensified combined BCG IL-2 maintenance treatment.

Therapeutic efficacy of the F8-IL2 immunocytokine in a metastatic mouse model of lung adenocarcinoma

OBJECTIVES

Antibody-cytokine fusion proteins (immunocytokines) represent a novel class of armed antibodies in oncology. In particular, IL2- and TNF-based immunocytokines targeting the EDB domain of fibronectin and the A1 domain of tenascin-C have demonstrated promising anti-tumor activity and are currently investigated in Phase I and Phase II clinical trials. To advance the development of immunocytokines for NSCLC, we here report on the therapeutic efficacy of F8-IL2, an immunocytokine directed against the alternatively spliced EDA domain of fibronectin in a fully immunocompetent, orthotopic model of NSCLC, and the characterization of the target antigen expression in human NSCLC specimens.

MATERIALS AND METHODS

We evaluated the therapeutic efficacy of the F8-IL2 immunocytokine utilizing a K-ras mutant, p53 deficient metastatic mouse model of NSCLC derived from the latest generation of genetically engineered and conditional tumor models. In parallel, we assessed the presence of the EDA domain of fibronectin by immunofluorescence in lung biopsies obtained from patients with NSCLC.

RESULTS

The EDA domain of fibronectin was broadly expressed in lung metastases obtained from our model. Treatment with F8-IL2 induced substantial local changes within immune effector cell populations and demonstrated promising therapeutic efficacy as monotherapy. The target of F8-IL2, the EDA domain of fibronectin, was present in all human lung adenocarcinoma specimens tested.

CONCLUSION

Both the therapeutic efficacy in a metastatic mouse model of NSCLC and the extensive presence of the EDA domain of fibronectin in human NSCLC biopsies support the rational development of therapies based on the F8-IL2 immunocytokine for the treatment of NSCLC.

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.

Th1 cytokine-secreting recombinant Mycobacterium bovis bacillus Calmette-Guérin and prospective use in immunotherapy of bladder cancer

Intravesical instillation of Mycobacterium bovis bacillus Calmette-Guérin (BCG) has been used for treating bladder cancer for 3 decades. However, BCG therapy is ineffective in approximately 30–40% of cases. Since evidence supports the T helper type 1 (Th1) response to be essential in BCG-induced tumor destruction, studies have focused on enhancing BCG induction of Th1 immune responses. Although BCG in combination with Th1 cytokines (e.g., interferon-α) has demonstrated improved efficacy, combination therapy requires multiple applications and a large quantity of cytokines. On the other hand, genetic manipulation of BCG to secrete Th1 cytokines continues to be pursued with considerable interest. To date, a number of recombinant BCG (rBCG) strains capable of secreting functional Th1 cytokines have been developed and demonstrated to be superior to BCG. This paper discusses current rBCG research, concerns, and future directions with an intention to inspire the development of this very promising immunotherapeutic modality for bladder cancer.

Investigational therapies for non-muscle invasive bladder cancer

IMPORTANCE OF THE FIELD

Bacillus Calmette-Guérin (BCG) is currently the most effective adjuvant intravesical agent at preventing disease recurrence and the only therapy shown to inhibit disease progression in non-muscle invasive bladder cancer (NMIBC). However, recurrence rates as high as 30% and significant local/systemic toxicity have resulted in an increased interest in the use of alternative intravesical agents.

AREAS COVERED IN THE REVIEW

Our aim is to discuss recent clinical trial evidence utilizing novel intravesical agents for treatment of NMIBC. A systematic literature review was performed via the National Center for Biotechnology Information databases to identify pertinent studies from 2000-2009.

WHAT THE READER WILL GAIN

A durable response has been demonstrated with alternative agents in patients refractory to or intolerant of BCG. This review compares the merits and shortcomings of these emerging agents, focusing on clinical trial safety and efficacy results.

TAKE HOME MESSAGE

Despite recent enthusiasm for novel agents, radical cystectomy remains the treatment of choice for patients with NMIBC who have failed intravesical therapy. However, evidence is accumulating that novel agents provide an efficacious alternative in patients refractory or intolerable to BCG or unfit for cystectomy. Further randomized prospective data are required to demonstrate a recurrence- and progression-free benefit compared with BCG.

Promoter hypermethylation in tumour suppressor genes and response to interleukin-2 treatment in bladder cancer: a pilot study

PURPOSE

Non-muscle invasive bladder cancer (BC) is a highly recurrent disease, with the first recurrences arising shortly after transurethral resection of the bladder (TURB). Topical administration of interleukin-2 (IL-2) has been shown as an effective adjuvant therapy for BC; however, predictive biomarkers that may identify suitable subgroups of patients are lacking. In this pilot study we sought to determine the prognostic value of epigenetic and genetic inactivation of tumour suppressor genes (TSGs) among BC patients treated with IL-2.

METHODS

After complete TURB, patients with multifocal superficial BC were treated with five daily intravesical instillations of IL-2. Promoter hypermethylation in six TSGs and the TP53 gene mutations were prospectively assessed by methylation-specific PCR and automated capillary single-strand conformation polymorphism in 21 primary bladder cancer specimens and ten bladder wall biopsies collected during follow-up.

RESULTS

After IL-2 treatment, 9 out of 21 (43%) patients did not develop recurrent tumour within the 1 year of follow-up period. The mean duration of recurrence-free survival in the rest of the study group was 112 days. In the current pilot study, BC with p16 gene hypermethylation had a lower risk of recurrence after treatment with IL-2, as compared to IL-2 treated BC without p16 hypermethylation (p = 0.02). Significant associations were observed between tumour grade and the mean methylation index (p = 0.003), as well as the hypermethylation of the RARbeta gene (p = 0.048).

CONCLUSION

Our preliminary data suggest that DNA methylation biomarkers may assist in selection of BC patients for efficient IL-2 therapy.

The targeted immunocytokine L19-IL2 efficiently inhibits the growth of orthotopic pancreatic cancer

PURPOSE

Effective control of pancreatic cancer has been hampered primarily by the lack of tumor specificity of current treatment modalities. The highly specific antibody-mediated delivery of therapeutic agents to the tumor microenvironment might overcome this problem. We therefore investigated the therapeutic efficacy of the targeted immunocytokine L19-Interleukin-2 (L19-IL2), consisting of the human single-chain Fv antibody L19, which is highly specific for the extradomain B (ED-B) of fibronectin, and the human cytokine IL-2, in pancreatic cancer.

EXPERIMENTAL DESIGN

Therapeutic effects of L19-IL-2, IL-2, and gemcitabine on tumor growth and metastasis were evaluated in orthotopic mouse models for pancreatic cancer. Immunohistochemistry was done to define ED-B expression, tumor necrosis, apoptosis, proliferation, and invasion of macrophages and natural killer (NK) cells. NK cells were depleted by i.v. injection of an anti-asialo-GM-1 antibody.

RESULTS

ED-B is selectively expressed in human pancreatic cancer and in primary tumors and metastases of the mouse models. L19-IL-2 therapy was clearly superior to untargeted IL-2 or gemcitabine and inhibited tumor growth and metastasis with remarkable long-term tumor control. Therapeutic effects were associated with the induction of extensive tumor necrosis and inhibition of tumor cell proliferation. Immunohistochemistry revealed an increase of macrophages and NK cells in the tumor tissue, suggesting immune-mediated mechanisms. The functional relevance of NK cells for the therapeutic effect of the targeted immunocytokine L19-IL-2 was confirmed by NK cell depletion, which completely abolished its antitumor efficacy.

CONCLUSIONS

These preclinical results strongly encourage the initiation of clinical studies using L19-IL-2 in pancreatic cancer.

Local therapy of cancer with free IL-2

This is a position paper about the therapeutic effects of locally applied free IL-2 in the treatment of cancer. Local therapy: IL-2 therapy of cancer was originally introduced as a systemic therapy. This therapy led to about 20% objective responses. Systemic therapy however was very toxic due to the vascular leakage syndrome. Nevertheless, this treatment was a break-through in cancer immunotherapy and stimulated some interesting questions: Supposing that the mechanism of IL-2 treatment is both proliferation and tumoricidal activity of the tumor infiltrating cells, then locally applied IL-2 should result in a much higher local IL-2 concentration than systemic IL-2 application. Consequently a greater beneficial effect could be expected after local IL-2 application (peritumoral = juxtatumoral, intratumoral, intra-arterial, intracavitary, or intratracheal = inhalation). Free IL-2: Many groups have tried to prepare a more effective IL-2 formulation than free IL-2. Examples are slow release systems, insertion of the IL-2 gene into a tumor cell causing prolonged IL-2 release. However, logistically free IL-2 is much easier to apply; hence we concentrated in this review and in most of our experiments on the use of free IL-2. Local therapy with free IL-2 may be effective against transplanted tumors in experimental animals, and against various spontaneous carcinomas, sarcomas, and melanoma in veterinary and human cancer patients. It may induce rejection of very large, metastasized tumor loads, for instance advanced clinical tumors. The effects of even a single IL-2 application may be impressive. Not each tumor or tumor type is sensitive to local IL-2 application. For instance transplanted EL4 lymphoma or TLX9 lymphoma were not sensitive in our hands. Also the extent of sensitivity differs: In Bovine Ocular Squamous Cell Carcinoma (BOSCC) often a complete regression is obtained, whereas with the Bovine Vulval Papilloma and Carcinoma Complex (BVPCC) mainly stable disease is attained. Analysis of the results of local IL-2 therapy in 288 cases of cancer in human patients shows that there were 27% Complete Regressions (CR), 23% Partial Regressions (PR), 18% Stable Disease (SD), and 32% Progressive Disease (PD). In all tumors analyzed, local IL-2 therapy was more effective than systemic IL-2 treatment. Intratumoral IL-2 applications are more effective than peritumoral application or application at a distant site. Tumor regression induced by intratumoral IL-2 application may be a fast process (requiring about a week) in the case of a highly vascular tumor since IL-2 induces vascular leakage/edema and consequently massive tumor necrosis. The latter then stimulates an immune response. In less vascular tumors or less vascular tumor sites, regression may require 9-20 months; this regression is mainly caused by a cytotoxic leukocyte reaction. Hence the disadvantageous vascular leakage syndrome complicating systemic treatment is however advantageous in local treatment, since local edema may initiate tumor necrosis. Thus the therapeutic effect of local IL-2 treatment is not primarily based on tumor immunity, but tumor immunity seems to be useful as a secondary component of the IL-2 induced local processes. If local IL-2 is combined with surgery, radiotherapy or local chemotherapy the therapeutic effect is usually greater than with either therapy alone. Hence local free IL-2 application can be recommended as an addition to standard treatment protocols. Local treatment with free IL-2 is straightforward and can readily be applied even during surgical interventions. Local IL-2 treatment is usually without serious side effects and besides minor complaints it is generally well supported. Only small quantities of IL-2 are required. Hence the therapy is relatively cheap. A single IL-2 application of 4.5 million U IL-2 costs about 70 Euros. Thus combined local treatment may offer an alternative in those circumstances when more expensive forms of treatment are not available, for instance in resource poor countries.

Immunotherapy for Orthotopic Murine Bladder Cancer Using Bacillus Calmette-Guerin Recombinant Protein Mpt-64

PURPOSE

We investigated the efficacy of the recombinant bacillus Calmette-Guerin subunit protein vaccine Mpt-64 for inducing cytokine production and suppressing orthotopic bladder tumor growth in mice.

MATERIALS AND METHODS

One mycobacteria candidate gene (Mpt-64) was cloned and ligated into eukaryotic expression vectors. The induction and efficiency of Mpt-64 protein expression were detected using Western blotting. Various doses of Mpt-64 proteins were instilled intravesically 6 times in 2 weeks after intravesical implantation of MBT-2 tumor cells in chemical injured urothelium. Systemic cytokine responses, tumor growth and cumulative survival rates were monitored.

RESULTS

In vitro expression of recombinant Mpt-64 subunit protein was efficient in our system. Mice treated with 100 and 200 microg Mpt-64 subunit proteins significantly inhibited orthotopic MBT-2 tumor growth in C3H/HeN mice compared with that in control and 50 microg treatment groups in terms of the tumor taking rate, bladder tumor burden and mortality rate. Meanwhile, marked increased serum interferon-gamma with a limited but significant increase in serum interleukin-2 was observed in mice treated with 100 and 200 microg Mpt-64 proteins compared with control and 50 microg treated groups.

CONCLUSIONS

A highly immunopotent recombinant Mpt-64 subunit protein of bacillus Calmette-Guerin was produced and it elicited immune responses with a high serum interferon-gamma level, inhibited orthotopic tumor growth and prolonged survival in tumor bearing mice. Thus, intravesical immunogenic therapy using recombinant Mpt-64 protein may be an alternative bacillus Calmette-Guerin regimen for superficial bladder cancer.

Interleukin-2 for the treatment of solid tumors other than melanoma and renal cell carcinoma

Interleukin-2 (IL-2) is a lymphokine produced by T cells whose main function is to stimulate the growth and cytotoxic response of activated T lymphocytes. It has been used to stimulate the immune system for the treatment of multiples tumors. This article is intended to review the reports published from 1990 to 2004 on the IL-2 treatment of tumors other than melanoma and renal carcinoma. A literature search was made in various databases (MEDLINE, EMBASE and BioAssay), focused on IL-2 clinical efficacy in such tumors. A selection was made over 150 publications reporting on administration of IL-2 in multiple tumors: lung carcinoma (small cell and non-small cell), colorectal, gastric, pancreatic, ovarian and breast cancer, sarcomas, hepatocarcinoma, mesothelioma, and brain, urological, and head and neck tumors. IL-2 was mainly used in metastatic disease, associated with other immunotherapy or chemotherapy schedules. We conclude that adjuvant IL-2 may be of value in early stages combined with standard treatment for colon and pancreas cancers. In other neoplasms, the indication for adjuvant IL-2 has been sporadic and does not allow conclusions to be drawn. Assessment of the efficacy of IL-2 combined with chemotherapy as treatment for advanced stages is complex, due to the lack of a control, and the variety of dosages and schemes. The activity of IL-2 in monotherapy or in association with immunotherapy is clinically relevant in hepatocarcinoma, mesothelioma and in malignant overflows as palliative treatment. Randomized trials would be required in order to be able to draw conclusions about its indication in other tumors.

Superficial transitional cell carcinoma: bacillus Calmette-Guérin (BCG) and other intravesical agents

Adjuvant immuno- and/or chemotherapy intravesically has become a standard at least for patients with intermediate or high risk for recurrence. Whereas in the past cystectomy was a first-line therapy for patients with carcinoma in situ or high-grade T1 bladder tumor, radical surgery is today reserved for non-BCG responders or early recurrent disease.

Treatment of stage III-IV nasopharyngeal carcinomas by external beam irradiation and local low doses of IL-2

The therapeutic effect of intratumoural application of Interleukin-2 (IL-2) was studied in patients with stage III-IV nasopharyngeal carcinoma (NPC) that received radiotherapy. Patients with stage III-IV NPC receiving a standard treatment of 7,000 cGy external beam irradiation have a mean disease-free survival of about 1.5 years. In this paper, we describe ten of these patients who were treated with additional peritumoural and intratumoural injections with 3 x 10(4) U IL-2 on 5 days in weeks 2, 4, and 6 of the 7-weeks' irradiation period. This combined treatment group was compared with a historical group of patients treated with standard irradiation alone. Local IL-2 therapy showed a marked clinical and statistical significant improvement of disease-free survival. After 5 years, 63% of the IL-2 treated patients were disease-free versus 8% of the control patients. These results suggest that the therapeutic results of radiotherapy can be significantly improved by combining it with local IL-2 treatment. To our knowledge, this is the first clinical report showing that local IL-2 therapy is effective against an infiltrative and locally metastasizing tumour in human patients.

Local interleukin 2 therapy is most effective against cancer when injected intratumourally

Local interleukin 2 (IL-2) therapy is more effective against systemic tumours than systemic IL-2 therapy, but it remains unclear whether IL-2 should be injected intratumourally or peritumourally. To investigate this question, we treated DBA/2 mice bearing a large subcutaneous syngeneic SL2 lymphoma with either intra or peritumoural IL-2 therapy. Both applications enhanced survival, but intratumourally injected IL-2 was more effective than peritumourally injected IL-2. Tumours started to regress 4 days after IL-2 injection. Tumour cells died at the IL-2 injection site, although IL-2 is not directly cytotoxic for SL2 cells in vitro. Tumour cell death correlated well with oedema and extravascular erythrocytes, but less with leukocyte infiltrates. In mice bearing two s.c. tumours, intratumoural application therapy of IL-2 in one tumour caused decrease in size of both tumours in 4-9 days after therapy. However, the IL-2 treated tumours regressed more strongly than the untreated tumours. We conclude that vascular leakage and/or tissue destruction inside the tumour may contribute to the enhanced effect of intratumoural IL-2 therapy compared to peritumoural IL-2 therapy. Hence, we recommend applying of intratumoural rather than peritumoural IL-2 therapy.

Local interleukin-2 and interleukin-12 therapy of bovine ocular squamous cell carcinomas

Interleukin-2 and interleukin-12 have been used independently to successfully treat the induced and the spontaneous tumours in animals. This trial was done to determine if a combination of IL-2 and IL-12 in the treatment of spontaneous bovine ocular squamous cell carcinomas (BOSCC) would be more successful than IL-2 or IL-12 therapy by themselves. For this trial, we selected 25 BOSCC tumours seen on Holstein Fresian cows in Beatrice, Zimbabwe. The cows were randomly assigned to a treatment group of 5 days of IL-2 (200,000 U/day), 5 days of IL-12 (0.5 microg/day) or 5 days of IL-2 (200,000 U/day) and IL-12 (0.5 microg/day). At 20 months after treatment, the IL-2 therapy group had 63% complete regressions; the combination group had 38% complete regressions, which were significantly higher than the IL-12 group, which had 0% complete regressions at 20 months, despite having 29% complete regressions at 6 months. These results show that IL-2 therapy by itself and in combination with IL-12 is more successful than IL-12 by itself. However, combination therapy does not improve the outcome in comparison to IL-2 as a single therapy. It also proves that IL-2 is consistently successful in the therapy of BOSCC with over 60% complete regression, which corresponds to a number of other studies we have done on IL-2 therapy of BOSCC [Rutten, V.P.M.G., Klein, W.R., De Jong, W.A., Misdorp, W., Den Otter, W., Steerenberg, P.A., De Jong, W.H., Ruitenberg, E.J., 1989. Local interleukin-2 therapy in bovine ocular squamous cell carcinoma. A pilot study. Cancer Immunol. Immunother. 30, 165--169; Stewart, R.J.E., Hill, F.W.G., Masztalerz, A., Jacobs, J.J.L., Koten, J.W., Den Otter, W., 2003. Local low dose interleukin-2 therapy of bovine ocular squamous cell carcinomas in cattle in Zimbabwe, submitted for publication; Den Otter, W., Hill, F.W.G., Klein, W.R., Koten, J.W., Steerenberg, P.A., De Mulder, P.H.M., Rutten, V.P.M.G., Ruitenberg, E.J., 1993. Low doses of interleukin-2 can cure large bovine ocular squamous cell carcinoma. Anticancer Res. 13, 2453-2455; Den Otter, W., Hill, F.W.G., Klein, W.R., Koten, J.W., Steerenberg, P.A., De Mulder, P.H., Rhode, C., Stewart, R., Faber, J.A., Ruitenberg, E.J., 1995. Therapy of bovine ocular squamous cell carcinoma with local doses of interleukin-2: 67% complete regressions after 20 months of follow-up. Cancer Immunol. Immunother. 41, 10-14].

In situ crosslinked biodegradable hydrogels loaded with IL-2 are effective tools for local IL-2 therapy

We investigated the therapeutic efficacy of recombinant human interleukin-2 (rhIL-2)-loaded, in situ gelling, physically crosslinked dextran hydrogels, locally applied to SL2 lymphoma in mice. The physical crosslinking was established by stereocomplex formation between d-lactic acid oligomers and l-lactic acid oligomers grafted separately to dextrans. The stereocomplex hydrogel as described in our manuscript has several favourable characteristics, which enables its use as system for the controlled release of pharmaceutically active proteins. Firstly, the hydrogel system is a physically crosslinked system. In physically crosslinked gels, the use of chemical crosslinking agents is avoided. Such agents can potentially inactivate the protein and can covalently link the protein to the hydrogel network. Secondly, the hydrogel formation takes place at room temperature and physiological pH, and, importantly, in an all-aqueous environment. All factors are important to preserve the three-dimensional structure, and thus the biological activity, of the protein to be entrapped and released from the gels. Thirdly, the gel formation does not occur instantaneously. This means that a liquid formulation can be injected which solidifies after injection (in situ gel formation is possible). Fourthly, no pH drop during degradation is expected during degradation. As a control, free rhIL-2 was administered locally in either a single injection or at five consecutive days. All mice received the same total dose of rhIL-2. The rhIL-2-loaded hydrogels released most IL-2 over a period of about 5 days. The biocompatibility and biodegradability of the gels were excellent, as there were no acute or chronic inflammatory reaction and as the gels were replaced completely by fibroblasts after 15 days. The therapeutic efficacy of rhIL-2-loaded in situ gelled hydrogels is very good, as was demonstrated in DBA/2 mice bearing SL2. The therapeutic effect of a single application of gels loaded with 1 x 10(6) IU rhIL-2 is at least comparable to the therapeutic effect of injection of an equal dose of free rhIL-2. All mice cured with rhIL-2-loaded hydrogels survived a subsequent challenge, rejecting 10(6) intraperitoneal (i.p.) injected SL2 cells. In conclusion, this study demonstrates that in situ gelling, physically crosslinked dextran hydrogels slowly release encapsulated rhIL-2 in such a way that it is intact and biologically and therapeutically active. These hydrogels may greatly enhance the clinical applicability of rhIL-2 immunotherapy as only a single treatment is required and as these hydrogels are completely biodegradable.

Immunotherapy for urological malignancies

PURPOSE

For decades urologists have successfully used immunotherapy in the battle against cancer. Interleukin-2 in renal cell carcinoma and bacillus Calmette-Guerin in bladder cancer are standard primary and/or adjunctive therapies for these diseases. Recent advances in our understanding of mechanisms governing immune system activation have fostered a myriad of novel immunotherapeutic approaches that show great promise in vivo but have had limited success in human trials to date. This review highlights current immunotherapy strategies that may prove to be successful treatments for urological cancers.

MATERIALS AND METHODS

We performed a MEDLINE literature search for articles relating to immunotherapy in bladder, prostate and renal cell carcinoma in animals and humans. We included the most promising developments in this review.

RESULTS

In addition to combining existing therapies to improve their efficacy, novel approaches that attempt to exploit the immune system ability to identify, target and eradicate malignancies are now being developed. These therapies include the use of antitumoral monoclonal and bi-specific antibodies, manipulation of T-lymphocyte costimulatory molecules and the administration of newly discovered cytokines as well as the development of antitumor vaccines.

CONCLUSIONS

To date the full potential of immunotherapy for the treatment of urological malignancies has not been recognized. As our knowledge of the immune system expands, so too may our ability to manipulate it to affect tumor regression. This review describes the most recent and most promising developments in immunotherapy for urological malignancies.

IL-2 loaded dextran microspheres with attractive histocompatibility properties for local IL-2 cancer therapy

Biodegradable dextran microspheres (MS) were developed as a slow-release system for interleukin-2 (IL-2) to apply them for local IL-2 therapy of cancer. We describe the tissue reactions induced by these MS without or with IL-2 in rats. Dextran MS stain bright red-purple with the periodic acid Schiff (PAS), visualising the exact spot of IL-2 release and its relation to the histological reaction pattern. Subcutaneously injected MS always form a well-circumscribed deposit. In the first 2 days there is a PMN inflammation within the MS-deposit, but the surroundings show only a scanty inflammatory reaction. The PMN reaction is replaced by an abundant macrophage reaction in particular in the MS-deposit. At day 21 a fibrous capsule of about 50 mum surrounds the deposit. The effect of IL-2 administered in its free form is mainly vascular, with vascular dilatation, vascular leakage and oedema. It is remarkable that lymphocytes are present in the injection area already at day 2. When IL-2 releasing MS were used, the various reactions induced by IL-2 and MS were amplified leading to local necrosis. We conclude that neither placebo MS nor IL-2 leads to necrosis after subcutaneous injection in rats. In contrast, when IL-2 was released from MS, then massive necrosis was induced. This might be due to increased phagocytosis or changes in the micro-niche due to the release of humoral factors by the infiltrating cells. This is probably fortuitous for local IL-2 therapy of cancer, as massive necrosis of tumour cells can be expected to lead to an increased antitumour reaction.

Expectant management of small, recurrent, noninvasive papillary bladder tumors

PURPOSE

The majority of patients with stage Ta or T1 bladder cancer will have a subsequent tumor. Many of these patients invariably undergo multiple transurethral resections to manage small subsequent tumors or recurrences. We report our experience monitoring patients whose subsequent tumors appear to be small, low grade and papillary.

MATERIALS AND METHODS

A total of 32 patients with small, papillary, low grade appearing tumors and a history of Ta or T1 transitional cell carcinoma were monitored. The decision to delay resection or fulguration and observe these tumors was based on bladder cancer history, endoscopic appearance of the tumor and presence or lack of symptoms. All patients had a previous Ta tumor, and the tumor being observed was always papillary and appeared to be low grade. The decision to resect the tumor(s) was based on change in appearance (size or configuration) at followup endoscopy or hematuria. Patient records were reviewed, and bladder cancer history and tumor observation periods were recorded. Several patients underwent a number of observation periods. Tumor grade and stage before the observation interval were compared to the pathology of the observed tumor(s) after eventual resection. Tumor growth rate was calculated based on estimated tumor size documented at each interval.

RESULTS

Mean patient age was 72 years (range 39 to 88). Mean time since diagnosis of bladder cancer (initial urothelial tumor event) was 71 months (range 12 to 139). Mean number of subsequent tumor episodes or recurrences per patient was 3.8 (range 1 to 10). Mean number of transurethral resections was 3.8. Mean tumor-free interval before development of a subsequent tumor or mean time to recurrence was 13.4 months based on 104 tumor episodes. Not all tumor recurrences were observed. Mean number of tumor observation periods per patient was 1.8 (range 1 to 5) with a mean duration of 10.09 months per period based on 56 observation intervals. Mean time since the beginning of the initial observation period was 38 months (range 6 to 126). Mean tumor growth rate for 37 tumors was 1.77 mm per month (range 0 to 5.8). Only 3 of 45 (6.7%) patients had tumor progression from a pre-observation, low grade, noninvasive (TaG1 to 2) to a high grade Ta or T1 tumor. In the 3 observation periods in which the patient's most recent tumor was T1, 2 (67%) patients had TaG1 on resection after observation. Every patient with a T1 tumor before observation of a small new tumor had a history of a Ta tumor. No disease progressed to muscle invasion.

CONCLUSIONS

Small, recurrent, low grade appearing bladder tumors are slow growing and pose minimal risk. Therefore, as an alternative to in office fulguration to minimize morbidity and cost associated with repeat transurethral resection it may not be necessary to remove these tumors promptly at new tumor occurrence or recurrence.

Comparison of the efficacy of local treatment of equine sarcoids with IL-2 or cisplatin/IL-2

Local interleukin-2 (IL-2) is effective in a number of experimental animal models and in veterinary and human cancer patients without discomforting side effects. The primary goal of this study was to compare the therapeutic effects and side effects of the local intratumoral administration of five or ten low doses of IL-2 with those of a combination of cisplatin and a single high dose of IL-2 in the treatment of equine sarcoids. The therapeutic effect (complete and partial regression) of local cisplatin together with a single high dose of IL-2 was significantly better than the combined effect of low doses of local IL-2 administered daily over 5 or 10 days (80% and 43%, respectively; P=0.02). Cisplatin/IL-2 and low doses of IL-2 induced 53% and 14% complete regressions, respectively ( P=0.02). Histological changes after cisplatin/IL-2 treatment were far more pronounced than after IL-2 only treatment and in several cases showed an enormous eosinophilic infiltrate.

Lymphocytic infiltration of bladder after local cellular immunotherapy

BACKGROUND

This is a case report of a patient who received cellular immunotherapy, in the form of local injections of autologous stimulated lymphocytes (ASL) into individual tumors in the urinary bladder. A major consideration in cellular immunotherapy being the ability of immune cells to reach all target areas, we hypothesized that direct delivery of effector cells into individual bladder tumors might assure such access.

METHODS

ASL were generated by exposing the patient's PBL to phytohemagglutinin and culturing them in the presence of IL-2 to expand the population. ASL were injected into the base of individual bladder tumors three times at intervals of 3 weeks.

RESULTS

The patient died of a myocardial infarct, unrelated to cell therapy, 20 days after the third injection. An autopsy was performed. Histological sections of the bladder showed extensive lymphocytic infiltration of virtually the entire organ.

DISCUSSION

No conclusions about the therapeutic efficacy of local immunotherapy using ASL are possible. Nevertheless, the observations reported, taken together with reports of therapeutic efficacy of other immunotherapy regimens in the management of bladder cancer, suggest that ready access of stimulated lymphocytes to all regions of the organ may account, in part, for the relatively high rate of therapeutic success reported for various immunotherapy regimens for this malignancy.

Therapeutic efficacy of IL-2-loaded hydrogels in a mouse tumor model

Interleukin-2 (IL-2) is a highly effective anticancer drug if it is applied locally for 5 consecutive days. In most cases this requires 5 invasive treatments, which is not usually acceptable for either the patient or the clinician. For this reason we have developed dextran-based hydrogels from which the required amount of encapsulated IL-2 (1-4 x 10(6) IU of IL-2) is gradually released during 5-10 days. Initially IL-2-containing macroscopic cylinder-shaped gels (implants), and later IL-2-containing injectable microspheres, were developed. These preparations were characterized in vitro, and the therapeutic activity was tested in DBA/2 mice with SL2 lymphosarcoma. The therapy was given to mice with a large and extensively metastasized tumor load (at least 5% of the body weight). If 1-4 x 10(6) IU of IL-2 was slowly released from the hydrogels over a period of 5-10 days, the therapeutic effects were very good and comparable to the effects of free IL-2 injections for 5 consecutive days. In conclusion, dextran-based hydrogels are promising systems for the controlled release of IL-2.

Non-specific, rapidly generated cytotoxicity in lymphocytes induced by BCG in vitro: no evidence of enhancing effect from preceding interaction between BCG and transitional cell line cells

PURPOSE

To study short-term events in the mechanism of action of BCG with an emphasis on the interaction between BCG and T24 cell line cells.

MATERIALS AND METHODS

Peripheral blood mononuclear cells (PBMNC) or/and several tumor cell lines were incubated with BCG (Oncotice) using various clinical and subclinical BCG concentrations.

RESULTS

3 h BCG incubation of PBMNC at 10(7) - 5*10(5) CFU/ml., followed by a 4 h cytotoxicity test, resulted in a significant augmentation of cytotoxicity of PBMNC against T24 cells, and the augmentation was almost significant at 10(5) CFU/ml. Overnight BCG incubation of PBMNC further augmented that cytotoxicity at all concentrations down to 10(4) CFU/ml. The minimum overall time (incubation with BCG + cytotoxicity test), where stimulation of PBMNC could be detected, was only 4 h. The BCG enhanced cytotoxicity of PBMNC could be demonstrated against all the tested cell line cells in a 4 h cytotoxicity test by using a preceding overnight BCG incubation of PBMNC, and against the majority of the cell lines by using a preceding 3 h BCG incubation of PBMNC. No convincing evidence was obtained to support the hypothesis that BCG should be first processed by T24 cells to make these cells more susceptible to cell mediated lysis by PBMNC.

CONCLUSIONS

Clinical and subclinical concentrations of BCG are directly stimulatory to PBMNC, which become, in a minimum time of a few hours, more capable of killing tumor cells, without a need for preceding interaction between BCG and tumor cells.

Recent perspectives in topical therapy in superficial bladder cancer

With regard to side-effects in intravesical bacillus Calmette-Guérin instillation therapy and the limited efficacy of intravesical chemotherapy, there is still a need for improvement of these standard therapies. Recently, technical adjuvant means or the modification of cytostatic drugs have been undertaken to improve the efficacy of intravesical chemotherapy. Prognostic indicators of the response to bacillus Calmette-Guérin immunotherapy have been identified, but indicators of side-effects are needed in order to improve the benefit-to-risk ratio of bacillus Calmette-Guérin instillation therapy. Many innovative treatment options, however, still require a definition of their clinical value.

Analysis of external and internal interlibrary loan requests: aid in collection management

The analysis of 60,779 external interlibrary loan requests for copies of periodical articles from the collection of Erasmus University Medical Library in 1988 is described. The study was used for planning the length of backruns to be retained due to space limitations that forced the disposal of older volumes. More than 50% of requests were for the most recent two-year period, and 90% of requests could be filled with a twenty-year run of periodicals. In 1989, 4,157 internal requests were received for periodicals not owned; these were analyzed to determine those most commonly requested. Prior to subscribing, new titles were reviewed as to price, bibliometric indicators, number of requests, length of backfile, and the number of requesting departments. The Library Advisory Board decides on cancellation or purchase of periodicals; the elements considered are described.