Bladder tissue pharmacokinetics of intravesical mitomycin C and suramin in dogs

Molecular characterization of trypanocide-resistant strains derived from a single field isolate of Trypanosoma evansi

Four strains (SB-PR, SB-RS, SB-RD, and SB-RM) of Trypanosoma evansi (T. evansi) were used in this study. SB-PR is known to be trypanocide-sensitive, while the others are trypanocide-resistant to suramin, diminazene diaceturate, and melarsomine hydrochloride, respectively. SB-RS, SB-RD, and SB-RM are derivatives of a single field isolate of SB-PR. Trypanocide resistance will not only increase costs and decrease production efficiency but will also affect effective treatment strategies. Therefore, studies on this topic are important to avoid inefficient production and ineffective treatment. This paper aims to presents a comparative molecular characterization of the trypanocide-resistant strains compared to the parent population. Comparative molecular characterization of these strains based on a protein profile analysis performed with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), DNA fingerprinting of random amplified polymorphic DNA (RAPD), and the molecular characterization of expression-site-associated 6 (ESAG6), variant surface glycoprotein (VSG), and T. evansi adenosine transporter-1 (TevAT1) gene sequences. The results show three derived strains (SB-RS, SB-RD, and SB-RM) exhibit different banding patterns than SB-PR. According to the RAPD results, SB-RS and SB-RD are different strains with DNA fingerprint similarities of about 77.8 %, while the DNA fingerprint of SB-RM has a similarity of 44.4 % to SB-RS and SB-RD. No differences in VSG were found among the four strains; however, ESAG6 showed differences in both nucleotide and amino acid sequences, as well as in its secondary and 3D structure. In conclusion, all molecular analyses of the ESAG6 gene showed that SB-PR, SB-RS, SB-RD, and SB-RM are different strains. Furthermore, SB-PR, SB-RS, SB-RD, and SB-RM did not exhibit the TevAT1 gene, so the resistance mechanism was determined to be unrelated to that gene.

Mathematical model of MMC chemotherapy for non-invasive bladder cancer treatment

Mitomycin-C (MMC) chemotherapy is a well-established anti-cancer treatment for non-muscle-invasive bladder cancer (NMIBC). However, despite comprehensive biological research, the complete mechanism of action and an ideal regimen of MMC have not been elucidated. In this study, we present a theoretical investigation of NMIBC growth and its treatment by continuous administration of MMC chemotherapy. Using temporal ordinary differential equations (ODEs) to describe cell populations and drug molecules, we formulated the first mathematical model of tumor-immune interactions in the treatment of MMC for NMIBC, based on biological sources. Several hypothetical scenarios for NMIBC under the assumption that tumor size correlates with cell count are presented, depicting the evolution of tumors classified as small, medium, and large. These scenarios align qualitatively with clinical observations of lower recurrence rates for tumor size ≤ 30[mm] with MMC treatment, demonstrating that cure appears up to a theoretical x[mm] tumor size threshold, given specific parameters within a feasible biological range. The unique use of mole units allows to introduce a new method for theoretical pre-treatment assessments by determining MMC drug doses required for a cure. In this way, our approach provides initial steps toward personalized MMC chemotherapy for NMIBC patients, offering the possibility of new insights and potentially holding the key to unlocking some of its mysteries.

Local Drug Delivery in Bladder Cancer: Advances of Nano/Micro/Macro-Scale Drug Delivery Systems

Treatment of bladder cancer remains a critical unmet need and requires advanced approaches, particularly the development of local drug delivery systems. The physiology of the urinary bladder causes the main difficulties in the local treatment of bladder cancer: regular voiding prevents the maintenance of optimal concentration of the instilled drugs, while poor permeability of the urothelium limits the penetration of the drugs into the bladder wall. Therefore, great research efforts have been spent to overcome these hurdles, thereby improving the efficacy of available therapies. The explosive development of nanotechnology, polymer science, and related fields has contributed to the emergence of a number of nanostructured vehicles (nano- and micro-scale) applicable for intravesical drug delivery. Moreover, the engineering approach has facilitated the design of several macro-sized depot systems (centimeter scale) capable of remaining in the bladder for weeks and months. In this article, the main rationales and strategies for improved intravesical delivery are reviewed. Here, we focused on analysis of colloidal nano- and micro-sized drug carriers and indwelling macro-scale devices, which were evaluated for applicability in local therapy for bladder cancer in vivo.

Chemoablation with Intensive Intravesical Mitomycin C Treatment: A New Approach for Non-muscle-invasive Bladder Cancer

BACKGROUND

Mitomycin C (MMC) is widely used, but the optimal dose and schedule have not been established.

OBJECTIVE

To evaluate the ablative power and patient safety of a short-term intensive schedule of intravesical MMC in patients with recurrent non-muscle-invasive bladder cancer (NMIBC).

DESIGN, SETTING, AND PARTICIPANTS

This was a prospective, single-center, nonrandomized study that compared 47 patients (group 1) with a history of low- to intermediate-risk NMIBC with long free-recurrence intervals, recurrence of ≤1cm in maximum diameter, and negative cytology to 47 consecutive patients with the same baseline characteristics (group 2).

INTERVENTION

Intravesical MMC three times per week for 2 wk for group 1. Transurethral resection of bladder tumor (TUR-BT) and early instillation and a weekly schedule of intravesical MMC for group 2. All cancer-free patients underwent monthly MMC maintenance. Follow-up included bladder mapping, voiding and washing urinary cytology, TUR of suspected area, TUR of previous tumor location, and ultrasound or computed tomography/magnetic resonance imaging.

OUTCOME MEASUREMENT AND STATISTICAL ANALYSIS

We used χ² and Student's t test for comparison of categorical and continuous variables, respectively. Kaplan-Meier curves were plotted to estimate cancer-free survival. The significance level was set to p<0.05.

RESULTS AND LIMITATIONS

The complete response rate at 39 mo was 61.7% in group 1 and 70.2% in group 2 (p=0.38). Kaplan-Mayer analysis revealed no difference in cancer-free survival rates overall (log-rank <3.84), according to tumor size in each group (log-rank <3.84), or between the groups (log-rank <7.82). No cases of systemic toxicity were observed. Local toxicities did not differ between the groups (p=0.32) and resolved on treatment of symptoms, and no patient discontinued their treatment. Limitations include the small number of patients, selection bias because of the single tertiary center, and short follow-up.

CONCLUSIONS

The proposed MMC schedule had good ablative power that can be explained by better concordance between the scheduled timing and the tumor cell duplication rate. The short-term intensive schedule could be considered as a therapeutic strategy to replace TUR-BT in selected NMIBC patients.

PATIENT SUMMARY

We report our experience of a tailored intravesical therapy schedule for bladder cancer. This schedule could be considered a therapeutic strategy to replace surgery for selected patients.

Lyso-thermosensitive liposomal doxorubicin for treatment of bladder cancer

PURPOSE

To evaluate lyso-thermosensitive liposomal doxorubicin (LTLD, ThermoDox®) in combination with loco-regional mild hyperthermia (HT) for targeted drug delivery to the bladder wall and potential treatment of bladder cancer.

MATERIAL AND METHODS

Porcine in vivo studies were performed with the following groups: (i) intravenous (IV) LTLD with hyperthermia (LTLD + HT); (ii) IV doxorubicin (DOX) with hyperthermia (IV DOX + HT) and (iii) IV LTLD without hyperthermia (LTLD - HT). Drug formulations were delivered via 30 min IV infusion coinciding with 1-h bladder irrigation (45 °C water for HT groups, 37 °C for non-HT group), followed by immediate bladder resection. DOX concentrations were measured in consecutive sections parallel to the bladder lumen by liquid chromatography following drug extraction. Computer models were developed to simulate tissue heating and drug release from LTLD.

RESULTS

Comparing mean DOX concentrations at increasing depths from the lumen to outer surface of the bladder wall, the ranges for LTLD + HT, IV DOX + HT and LTLD - HT, respectively, were 20.32-3.52 μg/g, 2.34-0.61 μg/g and 2.18-0.51 μg/g. The average DOX concentrations in the urothelium/lamina and muscularis, respectively, were 9.7 ± 0.67 and 4.09 ± 0.81 μg/g for IV LTLD + HT, 1.2 ± 0.39 and 0.86 ± 0.24 μg/g for IV DOX + HT, and 1.15 ± 0.38 and 0.62 ± 0.15 μg/g for LTLD - HT. Computational model results were similar to measured DOX levels and suggest adequate temperatures were reached within the bladder wall for drug release from LTLD.

CONCLUSIONS

Doxorubicin accumulation and distribution within the bladder wall was achieved at concentrations higher than with free IV doxorubicin by mild bladder hyperthermia combined with systemic delivery of LTLD.

Mitomycin C: new strategies to improve efficacy of a well-known therapy

Mitomycin C (MMC) as an intravesical chemotherapeutic agent is a well-known option for treatment of nonmuscle invasive bladder cancer (NMIBC) recurrence; it is probably the most commonly used agent given its low rate of side effects and its efficacy.Both the American Urologic Association (AUA) and European Association of Urology (EAU) consider MMC as a standard treatment for immediate single-dose postoperative treatment and for adjuvant therapy in low and intermediate-risk NMIBC.Despite the popularity of this agent in the treatment of NMIBCs, many questions regarding the optimal approach to MMC therapy remain unanswered and the schedule widely used is empirical.Nevertheless, even when the current optimal approaches to MMC administration are used, a large proportion of NMIBCs recur.This apparent treatment resistance might be overcome by an optimization of standard MMC therapy or with a combination of MMC with other agents that have different mechanisms of action.Strategies to enhance passive delivery of MMC have been well studied and multiple measures are recommended for implementation of use in routine clinical practice.A modified scheme of instillation seems to be an easy and inexpensive alternative to increase efficacy of intravesical MMC and to also use this agent with an ablative intent.Enhancing tumor response with a sequential therapy is another option that has been investigated, mostly for chemo-immunotherapy wherein the different mechanisms of action of Bacillus of Calmette and Guerìn (BCG) and MMC are combined to achieve a higher response.