Sustained-release Formulation of Mitomycin C to the Upper Urinary Tract Using a Thermosensitive Polymer: A Preclinical Study

Intravesical Therapy for Upper Urinary Tract Urothelial Carcinoma: A Comprehensive Review

Upper tract urothelial carcinoma (UTUC) poses unique challenges in diagnosis and treatment. This comprehensive review focuses on prophylactic intravesical therapy for UTUC, summarizing key aspects of intravesical therapy in various clinical scenarios, including concurrent with or following radical nephroureterectomy, kidney-sparing surgery, ureteroscopy-guided biopsy. The incidence of intravesical recurrence in UTUC after surgical treatment is significant, necessitating effective preventive measures. Intravesical therapy plays a vital role in reducing the risk of bladder recurrence following UTUC surgery. Tailoring timing, drug selection, dosage, and frequency is vital in optimizing treatment outcomes and reducing intravesical recurrence risk in UTUC. This review provides a comprehensive summary of the history, clinical trials, guideline recommendations, and clinical applications of intravesical therapy for UTUC. It also discusses the future directions based on current clinical needs and ongoing trials. Future directions entail optimizing dosage, treatment duration, and drug selection, as well as exploring novel agents and combination therapies. Intravesical therapy holds tremendous potential in improving outcomes for UTUC patients and reducing the risk of bladder recurrence. Although advancements have been made in UTUC treatment research, further refinements are necessary to enhance efficacy and safety.

Injectable Thermoresponsive Hydrogels for Cancer Therapy: Challenges and Prospects

The enervating side effects of chemotherapeutic drugs have necessitated the use of targeted drug delivery in cancer therapy. To that end, thermoresponsive hydrogels have been employed to improve the accumulation and maintenance of drug release at the tumour site. Despite their efficiency, very few thermoresponsive hydrogel-based drugs have undergone clinical trials, and even fewer have received FDA approval for cancer treatment. This review discusses the challenges of designing thermoresponsive hydrogels for cancer treatment and offers suggestions for these challenges as available in the literature. Furthermore, the argument for drug accumulation is challenged by the revelation of structural and functional barriers in tumours that may not support targeted drug release from hydrogels. Other highlights involve the demanding preparation process of thermoresponsive hydrogels, which often involves poor drug loading and difficulties in controlling the lower critical solution temperature and gelation kinetics. Additionally, the shortcomings in the administration process of thermosensitive hydrogels are examined, and special insight into the injectable thermosensitive hydrogels that reached clinical trials for cancer treatment is provided.

The Role of Local Agents for the Treatment of Localized Upper Tract Urothelial Carcinoma: A Review of the Current Evidence

Kidney-sparing surgery (KSS) for upper urinary tract urothelial carcinoma (UTUC) is a promising alternative to radical nephroureterectomy, especially for low-risk cases. However, due to the established risk of ipsilateral UTUC recurrence caused by the implantation of floating neoplastic cells after endoscopic resection, adjuvant endocavitary (endoureteral) instillations have been proposed. Instillation therapy may be also used as primary treatment for UTUC. The two most studied drugs that have been evaluated in both the adjuvant and primary setting of endocavitary instillation are mitomycin C and Bacillus Calmette-Guerin. The current paper provides an overview of the endocavitary treatments for UTUC, focusing on methods of administration, novel formulations, oncologic outcomes (in terms of endocavitary recurrence and progression), as well as on complications. In particular, the role of UGN-101 as a primary chemoablative treatment of primary noninvasive, endoscopically unresectable, low-grade, UTUC has been analysed. The drug achieved a complete response rate of 58% after the induction cycle, with a durable response independently of the maintenance cycle. The cumulative experience on the role of UUT instillation therapy appears encouraging; however, no definitive conclusions can be drawn about its therapeutic benefit. Given the current state of the art, any decision to administer adjuvant endoureteral therapy for UTUC should be carefully weighed against the potential adverse events. Nevertheless, newer investigations that improve visualization during ureteroscopy, genomic characterization, novel drugs and innovative strategies of improved drug delivery are under evaluation. The landscape of KSS for the treatment of the UTUC is evolving and seems promising.

Biodegradable ring-shaped implantable device for intravesical therapy of bladder disorders

Intravesical instillation is an efficient drug delivery route for the local treatment of various urological conditions. Nevertheless, intravesical instillation is associated with several challenges, including pain, urological infection, and frequent clinic visits for catheterization; these difficulties support the need for a simple and easy intravesical drug delivery platform. Here, we propose a novel biodegradable intravesical device capable of long-term, local drug delivery without a retrieval procedure. The intravesical device is composed of drug encapsulating biodegradable polycaprolactone (PCL) microcapsules and connected by a bioabsorbable Polydioxanone (PDS) suture with NdFeB magnets in the end. The device is easily inserted into the bladder and forms a 'ring' shape optimized for maximal mechanical stability as informed by finite element analysis. In this study, inserted devices were retained in a swine model for 4 weeks. Using this device, we evaluated the system's capacity for delivery of lidocaine and resiquimod and demonstrated prolonged drug release. Moreover, a cost-effectiveness analysis supports device implementation compared to the standard of care. Our data support that this device can be a versatile drug delivery platform for urologic medications.

Preparation of Aditoprim Injection against Streptococcus suis in Pigs and a Dose Regimen Based on Pharmacokinetic-Pharmacodynamic Modeling

In order to effectively treat the infection of Streptococcus suis and reduce the emergence of drug-resistant bacteria, an aditoprim (ADP) injection was developed in this study. The pharmaceutical property investigation results demonstrated that ADP injection was a clear yellow liquid with 10 g ADP distributing in every 100 mL solution uniformly. Its pH value and drug content were around 6.20 and 99.35~100.40%, respectively. And quality assessment preliminarily indicated its reliable quality and stability. Additionally, the bronchoalveolar lavage fluid method was first applied to evaluate accurate ADP concentration at infection site in this study. Through pharmacodynamic assay, the MIC, MBC and MPC of ADP against Streptococcus suis CVCC 607 was 2 μg/mL, 4 μg/mL and 12.8 μg/mL, respectively. The bacteria growth inhibition curves showed that ADP was a concentration-dependent antibacterial drug, and the PK-PD model parameter of AUC/MIC was selected. The pharmacokinetic parameters of alveolar fluid evaluated by WinNonlin software revealed similar pharmacokinetic process of ADP in healthy pigs and infected pigs. Combined with pharmacokinetics-pharmacodynamics (PK-PD) modeling, the dosage regimen of 3~5 days with an interval of 12 h at 4.10 mg/kg or 5.91 mg/kg could be adopted to treat the infection of Streptococcus suis. Consequently, this ADP injection with a multi-dose protocol would be a promising antimicrobial product for efficient treatment of S. suis infection of pigs.

Challenges and opportunities in the development of complex generic long-acting injectable drug products

Long-acting injectable (LAI) drug products enable the controlled release of a drug over an extended duration of time to improve the therapeutic effect, safety profile, or administration of an injectable product. The development of generic [505(j)] and differentiated [505(b)(2)] LAI products helps to provide patients and healthcare providers with more treatment options and to reduce overall healthcare costs, including those associated with drug product administration and patient compliance. In this review, we analyze the landscape of LAI products and identify the most common technical challenges that potential generic product entrants face. We focus on five formulation technologies that account for ~90% of approved LAI products, including those eligible for generic product registration over the next five years, to illustrate technology-specific challenges. We then review efforts from the U.S. Food and Drug Administration (FDA) to promote more generic product competition and emphasize the importance of collaboration among government, industry, and academia to advance the knowledge and capabilities of the scientific community. Regulatory bodies, industry, and academia are encouraged to anticipate challenges with emerging innovative LAI technologies and to leverage the experiences built on established technologies to foster generic product development.

Pharmacokinetics of UGN-101, a mitomycin-containing reverse thermal gel instilled via retrograde catheter for the treatment of low-grade upper tract urothelial carcinoma

PURPOSE

To evaluate the pharmacokinetic properties of UGN-101, a mitomycin-containing reverse thermal gel used as primary chemoablative treatment for low-grade upper tract urothelial carcinoma (UTUC), in a subset of patients participating in a phase 3 clinical trial.

METHODS

Pharmacokinetic parameters (C_max, T_max, AUC_(0-6), λz, t_½, and AUC_inf) were evaluated in six participants (male or female, ≥ 18 years) with biopsy-proven, low-grade UTUC who received the first of 6 once-weekly instillations of UGN-101 to the renal pelvis and calyces via retrograde ureteral catheter. Plasma samples were collected prior to instillation and 30 min, 1, 2, 3, 4, 5, and 6 h post-instillation. Safety was assessed by laboratory evaluations, physical exam, and adverse event monitoring.

RESULTS

The mean age of the six participants was 69 years; most were male (5/6) and Caucasian (5/6). Mean (SD) C_max was 6.24 (4.11) ng/mL and mean T_max was 1.79 (1.89) hours after instillation. Mean apparent t_½ following instillation was 1.27 (0.63) hours. Mean total systemic exposure to mitomycin up to 6 h post-instillation was 20.30 (19.69) ng h/mL. At 6 h post-instillation, mitomycin plasma concentrations of 5/6 participants were < 2 ng/mL. There were no clinically important adverse events or changes in laboratory values in any participant after a single instillation of UGN-101.

CONCLUSION

The reverse thermal gel formulation of UGN-101 is associated with higher concentration and extended dwell time of mitomycin in contact with the urothelium of the upper urinary tract while limiting systemic absorption of mitomycin.

REGISTRATION

NCT02793128; registered June 8, 2016.

History, presence, and future of mitomycin C in glaucoma filtration surgery

PURPOSE OF REVIEW

Mitomycin C (MMC) is an alkylating agent with extraordinary ability to crosslink DNA, preventing DNA synthesis. By this virtue, MMC is an important antitumor drug. In addition, MMC has become the gold standard medication for glaucoma filtration surgery (GFS). This eye surgery creates a passage for drainage of aqueous humor (AqH) out of the eye into the sub-Tenon's space with the aim of lowering the intraocular pressure. A major cause of failure of this operation is fibrosis and scarring in the sub-Tenon's space, which will restrict AqH outflow. Intraoperative application of MMC during GFS has increased GFS success rate, presumably mainly by reducing fibrosis after GFS. However, still 10% of glaucoma surgeries fail within the first year.

RECENT FINDINGS

In this review, we evaluate risks and benefits of MMC as an adjuvant for GFS. In addition, we discuss possible improvements of its use by adjusting dose and method of administration.

SUMMARY

One way of improving GFS outcome is to prolong MMC delivery by using a drug delivery system.

Loco-regional drug delivery in oncology: current clinical applications and future translational opportunities

Introduction: Drug-based treatment regimens for cancer are often associated with off-target toxic side effects and low penetration of the drug at the tumor site leading to patient morbidity and limited efficacy. Loco-regional drug delivery has the potential to increase efficacy while concomitantly reducing toxicity.Areas covered: Clinical applications using loco-regional delivery include intra-arterial drug delivery in retinoblastoma, direct intra-tumoral (IT) injection of ethanol for ablation in hepatocellular carcinoma (HCC) and the use of HIPEC in peritoneal carcinomas. In recent years, there has been a significant increase in both approved products and clinical trials, with a particular emphasis on drug delivery platforms such as drug-eluting beads for HCC and hydrogel platforms for intravesical delivery in bladder cancer.Expert opinion: Development of loco-regional drug-delivery systems has been slow, limited by weak clinical data for early applications and challenges relating to dosing, delivery and retention of drugs at the site of action. However, there is increasing focus on the potential of loco-regional drug delivery when combined with bespoke drug-delivery platforms. With the growth in immunotherapies, the use of IT delivery to drive priming of the anti-tumor response has opened up a new field of opportunity for loco-regional drug delivery.

A polymeric paste-drug formulation for local treatment of upper tract urothelial carcinoma

BACKGROUND

Intravesical instillation of chemo- or immunotherapy is commonly used in bladder cancer. Upper tract urothelial carcinoma (UTUC) shares similar pathological features, but current formulations are not suitable for direct instillation to the upper urinary tract.

OBJECTIVE

To evaluate in vivo applicability, characteristics and toxicity of ST-UC, a mucoadhesive polymeric paste formulation of gemcitabine, for upper urinary tract instillation.

MATERIAL AND METHODS

Three pigs received 10 ml of ST-UC (100 mg/ml gemcitabine) retrogradely into 1 renal pelvis for pharmacokinetic studies. Four days later, a second injection into the contralateral renal pelvis was followed by serial euthanasia of the pigs and nephroureterectomy after 1, 3, and 6 hours. Adverse effects were monitored. Urine, serum, and tissue gemcitabine concentrations were measured, along with histologic examination of the upper urinary tract.

RESULTS

Retrograde instillation of ST-UC was well tolerated with mild, completely receding hydronephrosis. Urine gemcitabine concentrations were highest in the first 3-hour collection interval. Hundred percent of gemcitabine was recovered in the urine within 24 hours. Serum peak concentrations (c_max) of gemcitabine were low at 5.5 µg/ml compared to the 10 to 30 µg/ml levels observed after a single intravenous dose of 1,000 mg/m² gemcitabine. The formulation was still traceable after one hour and gemcitabine tissue concentrations are supportive of this extended drug exposure. No major histopathological changes were observed. The main limitation of this study is the lack of antitumor activity data.

CONCLUSION

This preclinical evaluation of ST-UC demonstrated feasible instillation in the renal pelvis, no significant safety concerns, and sustained release of gemcitabine.

An evaluation of UGN-101, a sustained-release hydrogel polymer-based formulation containing mitomycin-C, for the treatment of upper urothelial carcinomas

INTRODUCTION

The treatment of low-grade upper tract urothelial carcinomas (UTUCs) after either surgery, or nephron-sparing techniques remains an unmet need in Genitourinary (GU) Oncology. UGN-101 is a novel drug in development for the treatment of UTUCs; it is composed of a sustained-release hydrogel polymer-based formulation containing the antitumor antibiotic mitomycin-C (MM-C); cold UGN-101 is liquid, but at body temperature, it becomes a gel, and thus, when administered through a ureteral catheter, it sticks to the upper tract urothelium, slowly releasing MM-C.

AREAS COVERED

Here, the authors review the preclinical rationale for the development of UGN-101, as well as presently available clinical results for the treatment of low-grade UTUCs.

EXPERT OPINION

The positive results of the recently completed OLYMPUS trial suggest the feasibility, activity (59% of complete responses, with just 6 of these complete responders on follow-up who recurred), and safety (68% of patients experiencing mild to moderate urinary adverse events) of UGN-101 instillations into the upper urinary tract. Our expectations are that UGN-101 will soon become a standard of treatment for low-grade UTUC at risk of relapse after either surgery, or nephron-sparing techniques.

Evaluation of the activity of a chemo-ablative, thermoresponsive hydrogel in a murine xenograft model of lung cancer

BACKGROUND

Minimally invasive intratumoural administration of thermoresponsive hydrogels, that transition from liquid to gel in response to temperature, has been proposed as a potential treatment modality for solid tumours. The aim of this study was to assess the inherent cytotoxicity of a poloxamer-based thermoresponsive hydrogel in a murine xenograft model of lung cancer.

METHODS

In vitro viability assessment was carried out in a lung cancer (A549) and non-cancerous (Balb/c 3T3 clone A31) cell line. Following intratumoural administration of saline or the thermoresponsive hydrogel to an A549 xenograft model in female Athymic Nude-Foxn1nu mice (n = 6/group), localisation was confirmed using IVIS imaging. Tumour volume was assessed using callipers measurements over 14 days. Blood serum was analysed for liver and kidney damage and ex vivo tissue samples were histologically assessed.

RESULTS

The thermoresponsive hydrogel demonstrated a dose-dependent cancer cell-specific toxicity in vitro and was retained in situ for at least 14 days in the xenograft model. Tumour volume increase was statistically significantly lower than saline treated control at day 14 (n = 6, p = 0.0001), with no associated damage of hepatic or renal tissue observed.

CONCLUSIONS

Presented is a poloxamer-based thermoresponsive hydrogel, suitable for intratumoural administration and retention, which has demonstrated preliminary evidence of local tumour control, with minimal off-site toxicity.

UGN-101 (mitomycin gel): a novel treatment for low-grade upper tract urothelial carcinoma

Upper tract urothelial carcinoma (UTUC) is a rare malignancy. The standard treatment for localized high-risk disease is radical nephroureterectomy, which confers significant morbidity and is not appropriate for all patients. Patients harboring low-risk, non-invasive disease may be candidates for organ-sparing treatment, which includes endoscopic resection with or without intracavitary drug therapy. Successful administration of intracavitary chemotherapy to the upper tracts is impeded by rapid washout of the agent and short dwell times. This has limited the clinical utility of mitomycin C for treatment of upper tract tumors, despite the successful outcomes observed in low-grade urothelial carcinoma of the bladder. Currently, there is an unmet need for development of a technically feasible and oncologically sound intracavitary therapy for management of low-grade UTUC. UGN-101 (Jelmyto™) is a novel formulation of mitomycin C that uses a unique hydrogel designed to increase urinary dwell time, and thereby efficacy of treatment. Preclinical data demonstrated promising results regarding the safety and feasibility of this agent. Preliminary results of a phase III trial (OLYMPUS study) [ClinicalTrials.gov identifier: NCT02793128] demonstrated the efficacy of UGN-101 as a successful chemo-ablative agent for low-grade upper tract tumors. UGN-101 may represent a pivotal paradigm shift in the treatment of low-grade UTUC. Indeed, the drug has recently been granted approval by the US Food and Drug Administration as the first treatment for low-grade UTUC, which may lead to significant improvements in patient care and a long-awaited decrease in the burden of disease.

Chemoablation in Urothelial Carcinoma: A Systematic Review and Future Perspectives

Chemoablation is an emerging treatment for urothelial carcinomas. This review provides an overview of the evidence for intracavitary chemoablation in the treatment of urothelial carcinomas. The benefits of such agents include a reduction in morbidity and diseased organ preservation. While numerous agents have shown promise, research is limited due to small patient cohorts, varying follow-up, and no standardized methodology to assess response. Therefore, to date, chemoablation has not been widely adopted. This may change as a novel mitomycin formulation has recently been approved for treating low-grade upper tract urothelial carcinoma. Future studies are ongoing which evaluate other promising chemoablation options in urothelial carcinoma.

Advancements in the clinical management of upper tract urothelial carcinoma

Introduction: Upper tract urothelial carcinoma (UTUC) remains a complex disease to manage given challenges in staging, surgical resection, use of perioperative therapy, and prevention of bladder recurrences. High-level evidence is limited to guide management; however, recent data have shifted treatment paradigms. We intend to review recent evidence on advancements in the clinical management for UTUC.Areas covered: This review summarizes advancements in pre-operative work-up, surgical technique, and the use of intravesical and systemic therapy in both the neoadjuvant and adjuvant settings. Special comment is made on progress in the genomics of UTUC and how that can inform clinical practice.Expert opinion: Advancements in the clinical management of UTUC are most prominently being made in the neoadjuvant chemotherapy setting. Although level I evidence is sparse, data from both single and multi-institutional retrospective studies strongly encourage the use of neoadjuvant chemotherapy especially in high-risk or advanced-stage patients.

Optimizing pharmacokinetics of intravesical chemotherapy for bladder cancer

Non-muscle-invasive bladder cancer (NMIBC) remains one of the most common malignancies and is associated with considerable treatment costs. Patients with intermediate-risk or high-risk disease can be treated with intravesical BCG, but many of these patients will experience tumour recurrence, despite adequate treatment. Standard of care in these patients is radical cystectomy with urinary diversion, but this approach is associated with considerable morbidity and lifestyle modification. As an alternative, perioperative intravesical chemotherapy is recommended for low-risk papillary NMIBC, and induction intravesical chemotherapy is an option for patients with intermediate-risk NMIBC and BCG-unresponsive NMIBC. However, poor pharmaceutical absorption and drug washout during normal voiding can limit sustained drug concentrations in the urothelium, which reduces efficacy, and small-molecule chemotherapeutic agents can be absorbed through the urothelium into the bloodstream, leading to systemic adverse effects. Several novel drug delivery methods - including hyperthermia, mechanical sustained released devices and nanoparticle drug conjugation - have been developed to overcome these limitations. These novel methods have the potential to be combined with established chemotherapeutic agents to change the paradigm of NMIBC treatment.

Organ-sparing procedures in GU cancer: part 3-organ-sparing procedures in urothelial cancer of upper tract, bladder and urethra

PURPOSE

The impact of radical surgery for urothelial carcinoma is significant on patient's quality of life. Organ-sparing surgery (OSS) can provide comparable oncological outcomes and with improved quality of life. In this review, we summarize the indications, techniques and outcomes of OSS for these tumors.

METHODS

PubMed^® was searched for relevant articles. Keywords used were: for upper tract urothelial carcinoma (UTUC): endoscopic, ureteroscopic/percutaneous management, laser ablation; for urothelial bladder cancer: bladder preservation, trimodal therapy, muscle invasive bladder cancer (MIBC); for urethral cancer: urethra/penile-sparing, urethral carcinoma.

RESULTS

Kidney-sparing surgery is an option in patients with low-risk UTUC with better renal function preservation and comparable oncological control to radical nephroureterectomy. In select patients with MIBC, trimodal therapy has better quality of life and comparable oncological control to radical cystectomy. In distal male urethral cancer, penile conserving surgery is feasible and offers acceptable survival outcomes. In female urethral cancer, organ preservation can be achieved, in addition to OSS, through radiation.

CONCLUSIONS

In the appropriately selected patient, OSS in upper tract, bladder and urethral carcinoma has comparable oncological outcomes to radical surgery and with the additional benefit of improved quality of life.

Optimal Management of Upper Tract Urothelial Carcinoma: an Unmet Need

OPINION STATEMENT

Upper tract urothelial carcinoma (UTUC) is a rare genitourinary entity of the renal pelvis and the ureter characterized by a more aggressive disease phenotype when compared with urothelial carcinoma of the bladder (UCB) with more than half of UTUC cases presenting with invasive disease at diagnosis compared to 20% for bladder tumors. There is growing evidence suggesting that its distinct natural history from that of bladder cancer can be related to several genetic and epigenetic differences. Treatment of low-risk disease consists of kidney-sparing surgeries such as ureteroscopic and percutaneous treatments, segmental ureterectomy, and adjuvant topical and intracavitary chemo-immunotherapies. The standard of care for high-risk non-metastatic disease remains radical nephroureterectomy and bladder cuff excision with increasing utilization rates of minimally invasive approaches leading to reduced morbidity without compromising outcomes while the role of lymphadenectomy is still being investigated. The prognosis of UTUC has been stagnant over the past decade highlighting the need for further studies on the role of multimodal therapy (neoadjuvant/adjuvant chemotherapy, immunotherapy, targeted therapy) to optimize management and improve outcomes.

A Custom Radiopaque Thermoresponsive Chemotherapy-Loaded Hydrogel for Intratumoural Injection: An In Vitro and Ex Vivo Assessment of Imaging Characteristics and Material Properties

PURPOSE

Thermoresponsive hydrogels are gels which have different properties at varying temperatures. The objective of this study was to assess the material characteristics, imaging properties and chemotherapeutic drug release profile of a novel radiopaque thermoresponsive hydrogel in vitro, which is liquid at room temperature but solidifies at body temperature, to determine potential suitability for intratumoural delivery.

MATERIALS AND METHODS

An iodinated radiopaque thermoresponsive hydrogel was formulated using iodixanol at a range of concentrations and assessed for sol-gel transition, radiopacity and imaging using CT and US. A lead formulation containing iodixanol at a concentration of 9.22% weight by weight (w/w, g of iodixanol per g of hydrogel) was evaluated in vitro for injectability, disintegration and dual drug release of cisplatin and paclitaxel from the hydrogel formulation.

RESULTS

Radiopacity of the hydrogel increased in a concentration-dependent manner, but the highest concentration of iodixanol evaluated in this study (13.83% w/w) adversely affected the sol-gel transition of the hydrogel; therefore, 9.22% w/w iodixanol hydrogel was identified as the lead formulation. This formulation was readily visible on both CT and US. The formulation was hand injectable through a range of clinically relevant devices, had a sustained disintegration profile for up to 28 days and was able to deliver a sustained release of chemotherapeutic drug for up to 10 days.

CONCLUSIONS

Favourable in vitro and ex vivo imaging and material characteristics of this thermoresponsive gel are demonstrated, suggesting potential interventional oncology applications for image-guided intratumoural delivery of sustained-release chemotherapy.

Current Therapeutic Strategies in Clinical Urology

The field of urology encompasses all benign and malignant disorders of the urinary tract and the male genital tract. Urological disorders convey a huge economic and patient quality-of-life burden. Hospital acquired urinary tract infections, in particular, are under scrutiny as a measure of hospital quality. Given the prevalence of these pathologies, there is much progress still to be made in available therapeutic options in order to minimize side effects and provide effective care. Current drug delivery mechanisms in urological malignancy and the benign urological conditions of overactive bladder (OAB), interstitial cystitis/bladder pain syndrome (IC/BPS), and urinary tract infection (UTI) will be reviewed herein. Both systemic and local therapies will be discussed including sustained release formulations, nanocarriers, hydrogels and other reservoir systems, as well as gene and immunotherapy. The primary focus of this review is on agents which have passed the preclinical stages of development.

Intracavitary therapies for upper tract urothelial carcinoma

INTRODUCTION

While radical nephroureterectomy remains the gold-standard for upper tract urothelial carcinoma (UTUC), there is a growing push for organ-sparing therapy in low-risk disease. Herein we review the use of intracavitary topical therapy for treatment of UTUC. Areas covered: A PubMed search was performed for studies pertaining to upper tract urothelial carcinoma, with 236 articles reviewed, and distilled for content pertinent to intracavitary therapy for UTUC. Topics discussed include agents used for management of UTUC, most commonly BCG, as well as techniques for administration. Additionally, we review the evidence for curative treatment for Cis versus adjuvant therapy for Ta/T1 disease. Finally, we discuss emerging technologies to improve agent delivery and efficacy in the upper tract. Expert commentary: No significant advances have occurred in topical management of UTUC in the past 2 decades. However, advances in diagnostic techniques such as modern ureteroscopes, and improved diagnostic imaging at the time of ureteroscopy may help improve our patient selection. Additional advances in topical therapy focused on increasing the duration of contact between agent delivered and the upper tract urothelium offer hope that a new leap forward in topical therapy is on the horizon.

Assessment of the efficacy of repeated instillations of mitomycin C mixed with a thermosensitive hydrogel in an orthotopic rat bladder cancer model

Background:

We investigated a thermoreversible hydrogel that is highly viscous at body temperature, while fluid-like at a low temperature, thus aiming for a slow and prolonged intravesical drug release. Our study purposed to assess antitumor efficacy of mitomycin C (MMC) mixed with hydrogel in an orthotopic rat bladder cancer model.

Methods:

Bladders of female Fischer F344 rats were grafted with 1.5 × 10⁶ AY-27 urothelial carcinoma cells. On day 5, tumor presence was assessed by cystoscopy and rats were divided into six groups (five treatment, one control, n = 10/group). Intravesical treatments (0.5 mg or 1 mg MMC-H₂O or MMC-hydrogel, or 2 mg MMC-hydrogel) were administered on days 5, 8 and 11. Rats were sacrificed at day 14 and bladders were evaluated.

Results:

Rats with tumor at cystoscopy (47/60) were evaluated for efficacy. At necropsy, all control animals (8/8) had tumors. No microscopic tumors were present in the 0.5 mg and 1 mg MMC-hydrogel groups compared with 2/8 and 1/8 rats in the 0.5 mg and 1 mg MMC-H₂O groups (p = 0.47 and p = 1.00, respectively).

Greater toxicity was seen in animals treated with MMC-hydrogel compared with MMC-H₂O, as demonstrated by lower body weights at necropsy (p = 0.000) and a tendency for more severe clinical signs in the 1 and 2 mg MMC-hydrogel groups. Rats that died prematurely received 1 mg (4/10) or 2 mg (9/10) of MMC-hydrogel.

Conclusions:

Under the current model conditions it is unclear whether instillation of MMC-hydrogel is more effective than MMC-H₂O. Nonetheless, the observed difference in toxicity, acting as a surrogate marker for systemic MMC exposure in the MMC-hydrogel-treated rats, supports the prolonged drug release mechanism of the hydrogel.

Induction and Maintenance Adjuvant Mitomycin C Topical Therapy for Upper Tract Urothelial Carcinoma: Tolerability and Intermediate Term Outcomes

PURPOSE

Endoscopic management of upper tract urothelial carcinoma (UTUC) is associated with higher recurrences, which could be reduced by application of topical therapy. Adjuvant induction Bacillus Calmette-Guerin has shown inferior outcomes for UTUC compared to bladder cancer, and maintenance regimens for UTUC are unexplored. We report on the efficacy, safety, and tolerability of Mitomycin C (MMC) induction and maintenance adjuvant topical therapy for UTUC.

MATERIALS AND METHODS

Patients with UTUC who received adjuvant topical therapy after complete endoscopic control of Ta/T1 tumors were retrospectively reviewed. Patients were treated using percutaneous nephrostomy tube (NT) or cystoscopically placed weekly ureteral catheters, per patient preference, and all patients were offered induction and maintenance. Standardized follow-up of every 3 months in the first year, then at a minimum every 6 months, with ureteroscopy and at least annual CT, was performed. Primary outcomes were recurrence-free, progression-free, nephroureterectomy-free rate and cancer-specific and overall survival. Secondary outcomes were safety and treatment tolerability.

RESULTS

Twenty-seven patients with 28 renal units received adjuvant topical therapy from January 2008 to March 2015. Median follow-up was 19 months (range 7-92). Three year recurrence-free, progression-free, and nephroureterectomy-free survival rates were 60% [confidence interval (95% CI): 42, 86%], 80% [95% CI: 64, 100%], and 76% [95% CI: 60, 97%]. Cancer-specific mortality rate was 0%, and 3-year overall survival was 92.9%. Nine patients experienced adverse outcomes, all related to interventions and none related to systemic toxicity.

CONCLUSIONS

Induction and maintenance adjuvant topical MMC for endoscopically resected UTUC is feasible, well tolerated and shows promising intermediate term data on recurrence, progression, and nephroureterectomy-free survival.