A Clinical Trial of the Intradermal TLR2 Agonist CADI-05 for BCG Recurrent and Unresponsive Non-Muscle Invasive Bladder Cancer

Tumor targeted delivery of mycobacterial adjuvant encapsulated chitosan nanoparticles showed potential anti-cancer activity and immune cell activation in tumor microenvironment

Targeting immunotherapeutics inside the tumor microenvironment (TME) with intact biological activity remains a pressing issue. Mycobacterium indicus pranii (MIP), an approved adjuvant therapy for leprosy has exhibited promising results in clinical trials of lung (NSCLC) and bladder cancer. Whole MIP as well as its cell wall fraction have shown tumor growth suppression and enhanced survival in mice model of melanoma, when administered peritumorally. Clinically, peritumoral delivery remains a procedural limitation. In this study, a tumor targeted delivery system was designed, where chitosan nanoparticles loaded with MIP adjuvants, when administered intravenously showed preferential accumulation within the TME, exploiting the principle of enhanced permeability and retention effect. Bio-distribution studies revealed their highest concentration inside the tumor after 6 h of administration. Interestingly, MIP adjuvant nano-formulations significantly reduced the tumor volume in the treated groups and increased the frequency of activated immune cells inside the TME. For chemoimmunotherapeutics studies, MIP nano-formulation was combined with standard dosage regimen of Paclitaxel. Combined therapy exhibited a further reduction in tumor volume relative to either of the MIP nano formulations. From this study a three-pronged strategy emerged as the underlying mechanism; chitosan and Paclitaxel have shown direct role in tumor cell death and the MIP nano-formulation activates the tumor residing immune cells which ultimately leads to the reduced tumor growth.

A systematic review on the available treatment modalities for Bacillus Calmette-Guérin-unresponsive carcinoma in situ and tumors in patients who are ineligible for or decline radical cystectomy

Introduction

Globally, urothelial bladder carcinoma is a disease which carries a poor prognosis. There are various treatment modalities for urothelial bladder carcinoma with intravesical Bacillus Calmette-Guérin immunotherapy being the most efficacious intravesical therapy and the treatment of choice for patients with carcinoma in situ. A number of chemotherapeutic drugs are also available for the management of Ta/T1 tumors such as mitomycin C and epirubicin. However, relapse and progression is quite common. The optimal management of patients with Bacillus Calmette-Guérin-unresponsive disease remains to be a challenge. The purpose of this study was to conduct a systematic review on the treatment modalities available for the management of Bacillus Calmette-Guérin-unresponsive carcinoma in situ and urothelial bladder carcinoma in patients who are ineligible or decline radical cystectomy.

Methods

Two authors independently searched three databases on the treatment modalities available for the management of Bacillus Calmette-Guérin-unresponsive carcinoma in situ and Bacillus Calmette-Guérin-unresponsive urothelial bladder carcinoma.

Results

The systematic search resulted in 15 studies. We recommend the use of intravesical CG0070 adenovirus or hyperthermic intravesical chemotherapy mitomycin C in patients with carcinoma in situ only disease. In patients with carcinoma in situ ± Ta/T1 disease, we recommend the use of intravesical radiofrequency-induced chemohyperthermia or electromotive drug administration of mitomycin C. In patients who have Ta/T1 disease, we recommend the use of either hyperthermic intravesical chemotherapy epirubicin or electromotive drug administration mitomycin C followed by chemohyperthermia mitomycin C. If any of these second line therapies fail, an alternative regimen would be a combination of gemcitabine, cabazitaxel, and cisplatin.

Conclusion

This recommendation is subject to the available resources and clinical expertise available in different hospitals. More studies using study designs such as randomized controlled trials comparing multiple drugs with larger sample sizes and regular follow-up intervals should be performed to accurately assess the different medications and aid in designing guidelines to guide the management of Bacillus Calmette-Guérin-unresponsive non-muscle invasive intravesical bladder cancer.

Targets for Therapy of Bladder Cancer

In 2018 bladder cancer (urothelial carcinoma) was ranked twelfth concerning worldwide diagnosis of malignancies. At the time point of diagnosis of bladder cancer, approximately 75% of patients present with a nonmuscle-invasive disease (NMIBC), while the remaining 25% show invasion of tumor cells in the muscle layer of the bladder wall (MIBC). Among NMIBC tumors, flat, high-grade carcinoma in situ (CIS) is a therapeutic challenge. CIS shows a tendency to invade the muscle tissue of the bladder wall and thus become a MIBC. Standard therapy of NMIBC (including CIS) is done via intravesical instillation of BCG (bacillus Calmette Guerin) inducing a local immune reaction that finally promotes elimination of bladder cancer cells. However, BCG treatment of NMIBC proves to be ineffective in approximately 40% of patients. Therefore, new therapeutic approaches for the treatment of bladder cancer are urgently needed. Among promising new treatment options that are currently being investigated are the use of immune checkpoint inhibitors, and targeted approaches attacking (among others) long noncoding RNAs, micro RNAs, cancer stem cells, PARP1, and receptor signaling pathways. Moreover, the use of antibody-drug-conjugates (ADCs) is investigated also in bladder cancer therapy. Another approach that has been successfully established in preclinical studies uses the cytotoxic power of the alpha-emitter Bi-213 coupled to an antibody targeting EGFR. Overexpression of EGFR has been demonstrated in the majority of patients suffering from CIS. Feasibility, safety, toxicity and therapeutic efficacy of intravesical instillation of Bi-213-anti-EGFR have been evaluated in a pilot study. Since the results of the pilot study proved to be promising, a further optimization of alpha-emitter immunotherapy in bladder cancer seems mandatory.