Serial retrograde instillations of sustained release formulation of mitomycin C to the upper urinary tract of the Yorkshire swine using a thermosensitive polymer: Safety and feasibility

The Safety, Tolerability, and Preliminary Efficacy of a Gemcitabine-releasing Intravesical System (TAR-200) in American Urological Association-defined Intermediate-risk Non-muscle-invasive Bladder Cancer Patients: A Phase 1b Study

Background and objective

Patients with intermediate-risk non-muscle-invasive bladder cancer (IR NMIBC) have a high risk of recurrence and need effective therapies to reduce the risk of disease recurrence or progression. This phase 1b study (NCT02720367) assessed the safety and tolerability of TAR-200, an intravesical drug delivery system, in participants with IR NMIBC.

Methods

Participants with recurrent IR NMIBC were eligible. Participants received either two 7-d or two 21-d TAR-200 dosing cycles over a 4-6-wk period in a marker lesion/ablation design. TAR-200 was placed in the window between the cystoscopy showing recurrent papillary disease and the subsequent complete transurethral resection of the bladder tumour. The primary endpoint was TAR-200 safety. The secondary endpoints included TAR-200 tolerability, pharmacokinetics, and preliminary efficacy.

Key findings and limitations

Twelve participants received TAR-200 treatment. No TAR-200-related serious or grade ≥ 3 treatment-emergent adverse events (TEAEs) occurred. Nine participants had grade ≤ 2 TAR-200-related TEAEs, with urgency, dysuria, and haematuria being most common. Two participants refused a second dosing cycle due to urinary urgency and frequency. Insertion and removal of TAR-200 was successful in all cases. Plasma gemcitabine concentrations remained below the lower limit of detection. Five participants (42%) had complete response (CR): four had pathological CR and one had CR based on visual assessment.

Conclusions and clinical implications

TAR-200 appears to be safe and well tolerated, with encouraging preliminary efficacy in participants with IR NMIBC. This study lays the groundwork for the multiple phase 2 and 3 global studies that are currently on-going for TAR-200.

Patient summary

In this study, researchers evaluated the safety of the novel drug delivery system TAR-200 in participants with intermediate-risk non-muscle-invasive bladder cancer. They concluded that TAR-200 was safe and well tolerated with promising antitumour activity.

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.

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.

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.

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.

Primary chemoablation of low-grade upper tract urothelial carcinoma using UGN-101, a mitomycin-containing reverse thermal gel (OLYMPUS): an open-label, single-arm, phase 3 trial

BACKGROUND

Most patients with low-grade upper tract urothelial cancer are treated by radical nephroureterectomy. We aimed to assess the safety and activity of a non-surgical treatment using instillation of UGN-101, a mitomycin-containing reverse thermal gel.

METHODS

In this open-label, single-arm, phase 3 trial, participants were recruited from 24 academic sites in the USA and Israel. Patients (aged ≥18 years) with primary or recurrent biopsy-proven, low-grade upper tract urothelial cancer (measuring 5-15 mm in maximum diameter) and an Eastern Cooperative Oncology Group performance status score of less than 3 (Karnofsky Performance Status score >40) were registered to receive six instillations of once-weekly UGN-101 (mitomycin 4 mg per mL; dosed according to volume of patient's renal pelvis and calyces, maximum 60 mg per instillation) via retrograde catheter to the renal pelvis and calyces. All patients had a planned primary disease evaluation 4-6 weeks after the completion of initial therapy, in which the primary outcome of complete response was assessed, defined as negative 3-month ureteroscopic evaluation, negative cytology, and negative for-cause biopsy. Activity (complete response, expected to occur in >15% of patients) and safety were assessed by the investigator in all patients who received at least one dose of UGN-101. Data presented are from the data cutoff on May 22, 2019. This study is registered with ClinicalTrials.gov, NCT02793128.

FINDINGS

Between April 6, 2017, and Nov 26, 2018, 71 (96%) of 74 enrolled patients received at least one dose of UGN-101. 42 (59%, 95% CI 47-71; p<0·0001) patients had a complete response at the primary disease evaluation visit. The median follow-up for patients with a complete response was 11·0 months (IQR 5·1-12·4). The most frequently reported all-cause adverse events were ureteric stenosis in 31 (44%) of 71 patients, urinary tract infection in 23 (32%), haematuria in 22 (31%), flank pain in 21 (30%), and nausea in 17 (24%). 19 (27%) of 71 patients had study drug-related or procedure-related serious adverse events. No deaths were regarded as related to treatment.

INTERPRETATION

Primary chemoablation of low-grade upper tract urothelial cancer with intracavitary UGN-101 results in clinically significant disease eradication and might offer a kidney-sparing treatment alternative for these patients.

FUNDING

UroGen Pharma.

Optimal Management of Upper Tract Urothelial Carcinoma: Current Perspectives

INTRODUCTION

Upper tract urothelial carcinoma (UTUC) is a relatively uncommon urologic malignancy for which there has not been significant improvement in survival over the past few decades, highlighting the need for optimal multi-modality management.

METHODS

A non-systematic review of the latest literature was performed to include relevant articles up to June 2019. It summarizes the epidemiologic risk factors associated with UTUC, including smoking, carcinogenic aromatic amines, arsenic, aristolochic acid, and Lynch syndrome. Molecular pathways underlying UTUC and potential druggable targets are outlined.

RESULTS

Surgical management for UTUC includes kidney-sparing surgery (KSS) for low-risk disease and radical nephroureterectomy (RNU) for high-risk disease. Endoscopic management of UTUC may include ureteroscopic or percutaneous resection. Topical instillation therapy post-KSS aims to reduce recurrence, progression and to treat carcinoma-in-situ; this may be achieved retrogradely (via ureteric catheterization), antegradely (via percutaneous nephrostomy) or via reflux through double-J stent. RNU, which may be performed via open, laparoscopic or robot-assisted approaches, is the gold standard treatment for high-risk UTUC. The distal cuff may be dealt with extravesical, transvesical or endoscopic techniques. Peri-operative chemotherapy and immunotherapy are increasingly utilized; level 1 evidence exists for adjuvant chemotherapy, but neoadjuvant chemotherapy is favored as kidney function is better prior to RNU. Immunotherapy is primarily reserved for metastatic UTUC but is currently being investigated in the perioperative setting.

CONCLUSION

The optimal management of UTUC includes a firm understanding of the epidemiological factors and molecular pathways. Surgical management includes KSS for low-risk disease and RNU for high-risk disease. Peri-operative immunotherapy and chemotherapy may be considered as evidence mounts.

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.

Temperature-responsive silk-elastinlike protein polymer enhancement of intravesical drug delivery of a therapeutic glycosaminoglycan for treatment of interstitial cystitis/painful bladder syndrome

Interstitial cystitis (IC), also known as painful bladder syndrome, is a debilitating chronic condition with many patients failing to respond to current treatment options. Rapid clearance, mucosal coating, and tight epithelium create strong natural barriers that reduce the effectiveness of many pharmacological interventions in the bladder. Intravesical drug delivery (IDD) is the administration of therapeutic compounds or devices to the urinary bladder via a urethral catheter. Previous work in improving IDD for IC has focused on the sustained delivery of analgesics within the bladder and other small molecule drugs which do not address underlying inflammation and bladder damage. Therapeutic glycosaminoglycans (GAG) function by restoring the mucosal barrier within the bladder, promoting healing responses, and preventing irritating solutes from reaching the bladder wall. There is an unmet medical need for a therapy that provides both acute relief of symptoms while alleviating underlying physiological sources of inflammation and promoting healing within the urothelium. Semi-synthetic glycosaminoglycan ethers (SAGE) are an emerging class of therapeutic GAG with intrinsic anti-inflammatory and analgesic properties. To reduce SAGE clearance and enhance its accumulation in the bladder, we developed a silk-elastinlike protein polymer (SELP) based system to enhance SAGE IDD. We evaluated in vitro release kinetics, rheological properties, impact on bladder function, pain response, and bladder inflammation and compared their effectiveness to other temperature-responsive polymers including Poloxamer 407 and poly(lactic-co-glycolic acid)-poly(ethylene glycol). SAGE delivered via SELP-enhanced intravesical delivery substantially improved SAGE accumulation in the urothelium, provided a sustained analgesic effect 24 h after administration, and reduced inflammation.

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.

Endoscopic Approaches to Upper Tract Urothelial Carcinoma

A select group of patients with upper tract urothelial carcinoma (UTUC) may meet indications for endoscopic management. Strategies for disease management are provided, based on a comprehensive review of the data using PubMed and Medline databases and marrying this with our experience with endoscopic management of UTUC. Endoscopic management of UTUC via retrograde or antegrade approaches is a viable treatment option for appropriately selected patients with low-risk UTUC, including those with low-grade, low-volume, and solitary tumors. However, recurrence risk limits these procedures to compliant patients under a vigilant surveillance program. Efficacious adjuvant therapies are needed to reduce local recurrences.