Evolution of immunotherapy in the treatment of non-muscle-invasive bladder cancer

Modulation of the tumor microenvironment in non-muscle-invasive bladder cancer by OncoTherad® (MRB-CFI-1) nanoimmunotherapy: effects on tumor-associated macrophages, tumor-infiltrating lymphocytes, and monoamine oxidases

Non-muscle-invasive bladder cancer (NMIBC) presents management challenges due to its high recurrence rate and a complex tumor microenvironment (TME). This study investigated the effects of OncoTherad® (MRB-CFI1) nanoimmunotherapy on the TME of BCG-unresponsive NMIBC, focusing on alterations in monoamine oxidases (MAO-A and MAO-B) and immune markers: CD163, FOXP3, CD8, and CX3CR1. A comparative analysis of immunoreactivities was made before and after OncoTherad® treatment and an immune score (IS) was established to evaluate the correlation between immunological changes and clinical outcomes. Forty bladder biopsies of twenty patients were divided into 2 groups (n = 20/group): 1 (pre-treatment biopsies); and 2 (post-treatment biopsies). Our results showed stable MAO-A levels but a significant (p < 0.05) decrease in MAO-B immunoreactivity after treatment, suggesting OncoTherad®'s efficacy in targeting the tumor-promoting and immunosuppressive functions of MAO-B. Significant (p < 0.05) reductions in CD163 and FOXP3 immunoreactivities were seen in post-treatment biopsies, indicating a decreased presence of M2 macrophages and Tregs. Corroborating with these results, we observed reductions in tumor histological grading, focality and size, factors that collectively enhanced recurrence-free survival (RFS) and pathological complete response (PCR). Moreover, elevated IFN-γ immunoreactivities in treated biopsies correlated with increased counts of CD8+ T cells and higher CX3CR1 expression, underscoring OncoTherad®'s enhancement of cytotoxic T cell functionality and overall antitumor immunity. The IS revealed improvements in immune responses post-treatment, with higher scores associated with better RFS and PCR outcomes. These findings validate OncoTherad®'s capability to modify the bladder cancer microenvironment favorably, promoting effective immune surveillance and response.

OncoTherad® (MRB-CFI-1) Nanoimmunotherapy: A Promising Strategy to Treat Bacillus Calmette-Guérin-Unresponsive Non-Muscle-Invasive Bladder Cancer: Crosstalk among T-Cell CX3CR1, Immune Checkpoints, and the Toll-Like Receptor 4 Signaling Pathway

This study assessed the safety and efficacy of OncoTherad® (MRB-CFI-1) nanoimmunotherapy for non-muscle invasive bladder cancer (NMIBC) patients unresponsive to Bacillus Calmette-Guérin (BCG) and explored its mechanisms of action in a bladder cancer microenvironment. A single-arm phase I/II study was conducted with 44 patients with NMIBC who were unresponsive to BCG treatment. Primary outcomes were pathological complete response (pCR) and relapse-free survival (RFS). Secondary outcomes comprised response duration and therapy safety. Patients' mean age was 65 years; 59.1% of them were refractory, 31.8% relapsed, and 9.1% were intolerant to BCG. Moreover, the pCR rate after 24 months reached 72.7% (95% CI), whereas the mean RFS reached 21.4 months. Mean response duration in the pCR group was 14.3 months. No patient developed muscle-invasive or metastatic disease during treatment. Treatment-related adverse events occurred in 77.3% of patients, mostly grade 1-2 events. OncoTherad® activated the innate immune system through toll-like receptor 4, leading to increased interferon signaling. This activation played a crucial role in activating CX3CR1+ CD8 T cells, decreasing immune checkpoint molecules, and reversing immunosuppression in the bladder microenvironment. OncoTherad® has proved to be a safe and effective therapeutic option for patients with BCG-unresponsive NMIBC, besides showing likely advantages in tumor relapse prevention processes.

Optimizing Boron Neutron Capture Therapy (BNCT) to Treat Cancer: An Updated Review on the Latest Developments on Boron Compounds and Strategies

Boron neutron capture therapy (BNCT) is a tumor-selective particle radiotherapy. It combines preferential boron accumulation in tumors and neutron irradiation. The recent initiation of BNCT clinical trials employing hospital-based accelerators rather than nuclear reactors as the neutron source will conceivably pave the way for new and more numerous clinical trials, leading up to much-needed randomized trials. In this context, it would be interesting to consider the implementation of new boron compounds and strategies that will significantly optimize BNCT. With this aim in mind, we analyzed, in this review, those articles published between 2020 and 2023 reporting new boron compounds and strategies that were proved therapeutically useful in in vitro and/or in vivo radiobiological studies, a critical step for translation to a clinical setting. We also explored new pathologies that could potentially be treated with BNCT and newly developed theranostic boron agents. All these radiobiological advances intend to solve those limitations and questions that arise during patient treatment in the clinical field, with BNCT and other therapies. In this sense, active communication between clinicians, radiobiologists, and all disciplines will improve BNCT for cancer patients, in a cost- and time-effective way.

New synthetic nano-immunotherapy (OncoTherad®) for non-muscle invasive bladder cancer: Its synthesis, characterization and anticancer property

Bacillus Calmette-Guérin (BCG)-based intravesical immunotherapy has been applied as gold standard treatment for high-risk non-muscle invasive bladder cancer (NMIBC) for almost half a century. However, several patients with high-risk disease experience relapse, including those whose condition has worsened and who failed to respond to BCG. Non-significant therapeutic options have been developed for these at-risk patients, for many years. Immunotherapies have shown promising outcomes for bladder cancer treatment. Accordingly, our research group developed the OncoTherad® (MRB-CFI-1) immunotherapy, which has shown positive outcomes in NMIBC treatment. The aim of the current study is to describe, in details, the physicochemical features and potential action mechanisms of OncoTherad® nano-immunotherapy, based on toll-like receptor 4 (TLR4)-mediated interferon and on RANK/RANKL signaling pathways, in animal model with NMIBC. Based on the current findings, OncoTherad® nano-immunotherapy did not have genotoxic effect on the investigated model and did not show signs of limiting local and/or systemic toxicity at therapeutic doses. OncoTherad® nano-immunotherapy was more effective than the BCG treatment, since it reduced by 70% the malignancy rate. Furthermore, it was possible identifying an important action mechanism of OncoTherad®, which was based on the modulation of TLR4-mediated interferon and RANK/RANKL signaling pathways that, altogether, were essential to reduce malignancy rate. OncoTherad® mechanisms in these pathways helped preventing tumor recurrence.

ALT-803 in the treatment of non-muscle-invasive bladder cancer: Preclinical and clinical evidence and translational potential

Bladder cancer (BCa) is one of the most common malignant tumors that cause death. Approximately 75%–85% of BCa develop into non-muscle-invasive bladder cancer (NMIBC). Bacillus Calmette-Guérin (BCG) is the gold standard for avoiding cystectomy in the treatment of NMIBC. Unfortunately, up to 30% of patients do not respond to BCG treatment, and up to 70% of BCG responders relapse. The United States Food and Drug Administration (FDA) approved valrubicin (1998) and pembrolizumab (2020) for the treatment of BCG-unresponsive (BCGu) NMBIC. However, the complete remission rate for valrubicin and pembrolizumab was only 16% and 40.6%, respectively. ALT-803 (N-803) is an IL-15 superagonist and reduces tumor burden by promoting the proliferation and activation of NK cells and CD8⁺ T cells. The FDA received (23 May 2022) and accepted to review (28 July 2022) the marketing submission of ALT-803 plus BCG for the treatment of BCGu NMIBC. However, the FDA previously rejected the application for oportuzumab monatox (OM) due to a lack of data comparing it with pembrolizumab on August 20, 2021. Interestingly, the clinical efficacy and safety of ALT-803 were higher than that of pembrolizumab and OM, suggesting that ALT-803 may be approved by FDA. This review aims to further knowledge of the preclinical and clinical evidence of ALT-803 in the treatment of NMIBC and discuss its translational potential.