Pharmacokinetics of intravesical doxorubicin in superficial bladder cancer patients

Voltammetric Sensor for Doxorubicin Determination Based on Self-Assembled DNA-Polyphenothiazine Composite

A novel voltammetric sensor based on a self-assembled composite formed by native DNA and electropolymerized N-phenyl-3-(phenylimino)-3H-phenothiazin-7-amine has been developed and applied for sensitive determination of doxorubicin, an anthracycline drug applied for cancer therapy. For this purpose, a monomeric phenothiazine derivative has been deposited on the glassy carbon electrode from the 0.4 M H2SO4-acetone mixture (1:1 v/v) by multiple potential cycling. The DNA aliquot was either on the electrode modified with electropolymerized film or added to the reaction medium prior to electropolymerization. The DNA entrapment and its influence on the redox behavior of the underlying layer were studied by scanning electron microscopy and electrochemical impedance spectroscopy. The DNA-doxorubicin interactions affected the charge distribution in the surface layer and, hence, altered the redox equilibrium of the polyphenothiazine coating. The voltametric signal was successfully applied for the determination of doxorubicin in the concentration range from 10 pM to 0.2 mM (limit of detection 5 pM). The DNA sensor was tested on spiked artificial plasma samples and two commercial medications (recovery of 90-95%). After further testing on real clinical samples, the electrochemical DNA sensor developed can find application in monitoring drug release and screening new antitumor drugs able to intercalate DNA.

Electrochemical DNA sensors for drug determination

In this review, recent achievements in the development of the DNA biosensors developed for the drug determination have been presented with particular emphasis to the main principles of their assembling and signal measurement approaches. The design of the DNA sensors is considered with characterization of auxiliary components and their necessity for the biosensor operation. Carbon nanomaterials, metals and their complexes as well as electropolymerized polymers are briefly described in the assembly of DNA sensors. The performance of the DNA sensors is summarized within 2017-2022 for various drugs and factors influencing the sensitivity and selectivity of the response are discussed. Special attention is paid to the mechanism of the signal generation and possible drawbacks in the analysis of real samples.

Co-Delivery of Cisplatin and Gemcitabine via Viscous Nanoemulsion for Potential Synergistic Intravesical Chemotherapy

Combined chemotherapy is an effective and safe treatment for cancers. Co-administration of cisplatin and gemcitabine produces a synergistic effect for bladder cancer treatment, so viscous microemulsions were developed for co-delivery of cisplatin and gemcitabine to extend the retention time and improve the permeability of chemotherapeutic drugs into the urothelium by intravesical administration. Results showed that the deposition amounts of cisplatin and gemcitabine significantly increased in in vitro and in vivo study. The penetration depth in bladder tissue samples increased from 60 to 120 μm. The dual-loaded formulation also showed thermodynamic and chemical stability, demonstrating that these gel-based microemulsions are promising drug delivery carriers for chemotherapy agents by intravesical administration.

Current status of clinical trials assessing oncolytic virus therapy for urological cancers

Oncolytic virus therapy has recently been recognized as a promising new option for cancer treatment. Oncolytic viruses replicate selectively in cancer cells, thus killing them without harming normal cells. Notably, T-VEC (talimogene laherparepvec, formerly called OncoVEX^GM-CSF ), an oncolytic herpes simplex virus type 1, was approved by the US Food and Drug Administration for the treatment of inoperable melanoma in October 2015, and was subsequently approved in Europe and Australia in 2016. The efficacies of many types of oncolytic viruses against urological cancers have been investigated in preclinical studies during the past decade, and some have already been tested in clinical trials. For example, a phase I trial of the third-generation oncolytic Herpes simplex virus type 1, G47Δ, in patients with prostate cancer was completed in 2016. We summarize the current status of clinical trials of oncolytic virus therapy in patients with the three major urological cancers: prostate, bladder and renal cell cancers. In addition to Herpes simplex virus type 1, adenoviruses, reoviruses, vaccinia virus, Sendai virus and Newcastle disease virus have also been used as parental viruses in these trials. We believe that oncolytic virus therapy is likely to become an important and major treatment option for urological cancers in the near future.

Management of non-muscle-invasive (superficial) bladder cancer

Non-muscle-invasive (superficial) bladder cancer (NMIBC) represents 80% of incident cases of bladder cancer, and is characterized by a generally good prognosis, with a tendency to remain localized. Only 10%-20% of cases progress to invasion and/or metastasis. The biggest problem in management is the potential for local recurrence, and this will occur with relatively predictable prognostic determinants. Gene expression and other cell surface determinant are associated with outcome. In most cases, successful management is predicated on careful history taking and physical assessment, meticulous endoscopic assessment, and transurethral resection of bladder tumor tissue where indicated. Histology determines the potential for recurrence. Options of treatment include repeat resection, immunologic therapy via intravesical instillation, and the use of intravescally administered cytotoxic agents, including mitomycin C, doxorubicin, gemcitabine, and selected investigational compounds. Of importance, as some cases have the potential to invade and metastasize, timing of cystectomy for recurrent, high-risk tumors is important to avoid unnecessary morbidity and mortality.

Oncolytic viruses in the treatment of bladder cancer

Bladder carcinoma is the second most common malignancy of the urinary tract. Up to 85% of patients with bladder cancer are diagnosed with a tumor that is limited to the bladder mucosa (Ta, T1, and CIS). These stages are commonly termed as non-muscle-invasive bladder cancer (NMIBC). Although the treatment of NMIBC has greatly improved in recent years, there is a need for additional therapies when patients fail bacillus Calmette-Guérin (BCG) and chemotherapeutic agents. We propose that bladder cancer may be an ideal target for oncolytic viruses engineered to selectively replicate in and lyse tumor cells leaving normal cells unharmed. In support of this hypothesis, here we review current treatment strategies for bladder cancer and their shortcomings, as well as recent advancements in oncolytic viral therapy demonstrating encouraging safety profiles and antitumor activity.

Intraperitoneal therapy for peritoneal cancer

Cancers originating from organs in the peritoneal cavity (e.g., ovarian, pancreatic, colorectal, gastric and liver) account for approximately 250,000 new cancer cases annually in the USA. Peritoneal metastases are common owing to locoregional spread and distant metastases of extraperitoneal cancers. A logical treatment is intraperitoneal therapy, as multiple studies have shown significant targeting advantage for this treatment, including significant survival benefits in stage III, surgically debulked ovarian cancer patients. However, the clinical use of intraperitoneal therapy has been limited, in part, by toxicity, owing to the use of indwelling catheters or high drug exposure, by inadequate drug penetration into bulky tumors (>1 cm) and by the lack of products specifically designed and approved for intraperitoneal treatments. This article provides an overview on the background of peritoneal metastasis, clinical research on intraperitoneal therapy, the pharmacokinetic basis of drug delivery in intraperitoneal therapy and our development of drug-loaded tumor-penetrating microparticles.

Paclitaxel and cisplatin as intravesical agents against non-muscle-invasive bladder cancer

OBJECTIVES

To investigate the effects of cisplatin and paclitaxel against human bladder cancer cells in vitro, and to obtain both pharmacokinetic and pharmacodynamic data after intravesical administration in mice.

MATERIALS AND METHODS

Six bladder cancer cell lines (J82, KU7, RT4, SW780, T24, UMUC3) were treated with various combined doses of both drugs and cell proliferation was evaluated 3 days later. In vivo, solutions of cisplatin and micellar paclitaxel were instilled transurethrally in female mice and pharmacokinetic data were acquired using high-performance liquid chromatography-mass spectrometry and atomic absorption methods. To obtain efficacy data, mice with orthotopic KU7-luc tumours were administered cisplatin and/or micellar paclitaxel intravesically, and the tumour burden quantified using bioluminescence imaging.

RESULTS

In vitro, both cisplatin and paclitaxel potently decreased the proliferation of all cell lines tested, and in combination had an additive but not a synergistic effect. After intravesical instillation, mouse serum concentrations of cisplatin and paclitaxel were in the low microgram/millilitre range and bladder tissue concentrations achieved were 82 and 241 microg/g, respectively. Similar drug levels were reached using combined therapy. In vivo, all chemotherapeutic agents significantly inhibited bladder tumour growth, with the best results for combined therapy and micellar paclitaxel alone. However, there was toxicity in the combined treatment arm.

CONCLUSIONS

Both cisplatin and paclitaxel were absorbed at effective amounts into bladder tissues. As intravesical agents, paclitaxel had slightly stronger anticancer potency than cisplatin. Due to increased adverse events, caution should be exercised when combining both cisplatin and paclitaxel intravesically.

Intravesical treatments of bladder cancer: review

For bladder cancer, intravesical chemo/immunotherapy is widely used as adjuvant therapies after surgical transurethal resection, while systemic therapy is typically reserved for higher stage, muscle-invading, or metastatic diseases. The goal of intravesical therapy is to eradicate existing or residual tumors through direct cytoablation or immunostimulation. The unique properties of the urinary bladder render it a fertile ground for evaluating additional novel experimental approaches to regional therapy, including iontophoresis/electrophoresis, local hyperthermia, co-administration of permeation enhancers, bioadhesive carriers, magnetic-targeted particles and gene therapy. Furthermore, due to its unique anatomical properties, the drug concentration-time profiles in various layers of bladder tissues during and after intravesical therapy can be described by mathematical models comprised of drug disposition and transport kinetic parameters. The drug delivery data, in turn, can be combined with the effective drug exposure to infer treatment efficacy and thereby assists the selection of optimal regimens. To our knowledge, intravesical therapy of bladder cancer represents the first example where computational pharmacological approach was used to design, and successfully predicted the outcome of, a randomized phase III trial (using mitomycin C). This review summarizes the pharmacological principles and the current status of intravesical therapy, and the application of computation to optimize the drug delivery to target sites and the treatment efficacy.

New potential therapy for orthotopic bladder carcinoma by combining HVJ envelope with doxorubicin

PURPOSE

To establish a new therapeutic method to treat bladder carcinoma, we investigated the therapeutic potential of doxorubicin hydrochloride (DXR) combined with hemagglutinating virus of Japan-envelope vector (HVJ-E) in an orthotropic mouse bladder cancer model.

METHODS

DXR and/or HVJ-E were instilled into the bladder after implantation of MB49 cells. Antitumor effects of combination therapy were evaluated by histological analysis of the bladder on day 14 after tumor implantation. The survival rate of MB49-disseminated mice was examined for 60 days after single or double administration of DXR alone or DXR/HVJ-E. The surviving mice were re-challenged with intravesical injection of MB49 cells, and the bladder was observed after 3 weeks.

RESULTS

Combined intravesical instillation of HVJ-E and DXR resulted in a significantly higher rate of tumor-free mice (11/21) compared with mice treated using DXR alone (3/19, P<0.05). Median survival was >60 days for intravesical instillation of HVJ-E and DXR, compared with the 29 days for DXR instillation alone (P<0.05). After combination therapy, surviving mice formed no tumors in the bladder following intravesical re-instillation of MB49.

CONCLUSIONS

HVJ-E increased antitumor effects in combination with chemotherapeutic agent (DXR). Antitumor immunity appeared to be enhanced using HVJ-E.

Computational Modeling to Predict Effect of Treatment Schedule on Drug Delivery to Prostate in Humans

PURPOSE

To evaluate a computational approach that incorporates experimental data in preclinical models to depict doxorubicin human tissue pharmacokinetics.

EXPERIMENTAL DESIGN

Beagle dogs were given 2 mg/kg doxorubicin as i.v. bolus, 4-h infusion, or 96-h infusion. Concentrations in plasma, prostate (target tissue), heart (toxicity), and major tissues for disposition were determined and modeled. Model parameters were obtained after the bolus injection with model validation based on the 4-h and 96-h infusion data. Clinical pharmacokinetic data and scale-up gave doxorubicin profiles in human prostate and heart.

RESULTS

In agreement with in vitro results, tissues were best modeled with two compartments, one rapidly and one slowly equilibrating. The developed tissue distribution model predicted concentrations for all three administration regimens well, with an average deviation of 34% (median, 29%). Interspecies scale-up to humans showed that the change from a bolus injection to a slow, 96-h infusion (a) had different effects on the drug partition and accumulation in heart and prostate, and (b) lowered the peak concentration in the plasma by approximately 100-fold but had relatively little effect on maximal heart concentration ( approximately 33% lower). The simulated drug exposure in a human prostate was above the exposure required to inhibit tumor proliferation but was 30 to 50 times below that needed for cell death.

CONCLUSION

The present study shows a computation-based paradigm for translating in vitro and in vivo preclinical data and to estimate and compare the drug delivery and pharmacokinetics in target tissues after different treatment schedules.

Practical Applications of Intravesical Chemotherapy and Immunotherapy in High-risk Patients with Superficial Bladder Cancer

The following steps are practical in the treatment of intermediate-to-high risk patients with superficial bladder cancer: Resect all visible tumor at the time of first TUR of bladder tumor. Strongly consider re-resection, especially for high-risk, large, multifocal, stage T1 tumors. Apply one dose of cytotoxic chemotherapy perioperatively within 6 hours of TUR (ideally immediately). Once histopathology is available, consider intravesical induction chemotherapy for intermediate-risk patients and BCG for intermediate- or high-risk patients and those having failed prior chemotherapy. At least 1 year of maintenance therapy should be planned for all intermediate-to-high risk BCG-treated patients. Chemotherapy maintenance may be useful if perioperative chemotherapy was omitted. For patients failing standard therapy, a thorough discussion of the risks (including progression and metastasis) and expected benefits should take place before the initiation of salvage therapy. The radical cystectomy option should be openly entertained. Consider BCG plus interferon or gemcitabine-based salvage programs if appropriate. Explore clinical trial options. Contact urologic cancer experts for guidance and advice.

Paclitaxel-Loaded Gelatin Nanoparticles for Intravesical Bladder Cancer Therapy

PURPOSE

The present report describes the development of paclitaxel-loaded gelatin nanoparticles for use in intravesical therapy of superficial bladder cancer. The commercial formulation of paclitaxel contains Cremophor, which forms micelles and thereby entraps the drug and reduces its partition across the urothelium.

EXPERIMENTAL DESIGN

Paclitaxel-loaded gelatin nanoparticles were prepared using the desolvation method, and their physicochemical and biological properties were characterized.

RESULTS

The size of the particles ranged from 600 to 1,000 nm and increased with the molecular weight of the gelatin polymer. Under optimal conditions, the yield was >80%, and the drug loading was 0.7%. Wide-angle X-ray diffraction analysis showed that the entrapped paclitaxel was present in an amorphous state, which has higher water solubility compared with the crystalline state. Identical, rapid drug release from nanoparticles was observed in PBS and urine, with approximately 90% released at 37 degrees C after 2 hours. Treatment with a protease (i.e., Pronase) rapidly degraded the nanoparticles, with half-lives of 23.8 minutes, 0.6 minute, and 0.4 minute in the presence of 0.01, 0.05, and 0.25 mg/mL Pronase, respectively. The paclitaxel-loaded nanoparticles were active against human RT4 bladder transitional cancer cells; the IC50 paclitaxel-equivalent concentrations were nearly identical to those of aqueous solutions of paclitaxel, i.e., approximately 30 nmol/L (equivalent to approximately 25 ng/mL) for 2-hour treatments and approximately 4 nmol/L for 96-hour treatments. In dogs given an intravesical dose of paclitaxel-loaded particles, the drug concentrations in the urothelium and lamina propria tissue layers, where Ta and T1 tumors would be located, were 7.4 +/- 4.3 mug/g (mean +/- SD; 3 dogs; 9 tissue sections), which were 2.6x the concentrations we reported for dogs treated with the Cremophor formulation.

CONCLUSIONS

Paclitaxel-loaded gelatin nanoparticles represent a rapid release, biologically active paclitaxel formulation that can be used for intravesical bladder cancer therapy.

Time- and concentration-dependent penetration of doxorubicin in prostate tumors

The penetration of paclitaxel into multilayered solid tumors is time- and concentration-dependent, a result of the drug-induced apoptosis and changes in tissue composition. This study evaluates whether this tissue penetration property applies to other highly protein-bound drugs capable of inducing apoptosis. The penetration of doxorubicin was studied in histocultures of prostate xenograft tumors and tumor specimens obtained from patients who underwent radical prostatectomy. The kinetics of drug uptake and efflux in whole tumor histocultures were studied by analyzing the average tumor drug concentration using high-pressure liquid chromatography. Spatial drug distribution in tumors and the drug concentration gradient across the tumors were studied using fluorescence microscopy. The results indicate that drug penetration was limited to the periphery for 12 hours in patient tumors and to 24 hours in the more densely packed xenograft tumors. Subsequently, the rate of drug penetration to the deeper tumor tissue increased abruptly in tumors treated with higher drug concentrations capable of inducing apoptosis (i.e., = 5 microm), but not in tumors treated with lower concentrations. These findings indicate a time- and concentration-dependent penetration of doxorubicin in solid tumors, similar to that of paclitaxel. We conclude that doxorubicin penetration in solid tumors is time- and concentration-dependent and is enhanced by drug-induced cell death.

Methods to improve efficacy of intravesical mitomycin C: results of a randomized phase III trial

BACKGROUND

Intravesical chemotherapy (i.e., placement of the drug directly in the bladder) with mitomycin C is beneficial for patients with superficial bladder cancer who are at high risk of recurrence, but standard therapy is empirically based and patient response rates have been variable, in part because of inadequate drug delivery. We carried out a prospective, two-arm, randomized, multi-institutional phase III trial to test whether enhancing the drug's concentration in urine would improve its efficacy.

METHODS

Patients with histologically proven transitional cell carcinoma and at high risk for recurrence were eligible for the trial. Patients in the optimized-treatment arm (n = 119) received a 40-mg dose of mitomycin C, pharmacokinetic manipulations to increase drug concentration by decreasing urine volume, and urine alkalinization to stabilize the drug. Patients in the standard-treatment arm (n = 111) received a 20-mg dose without pharmacokinetic manipulations or urine alkalinization. Both treatments were given weekly for 6 weeks. Primary endpoints were recurrence and time to recurrence. Treatment outcome was examined by use of Kaplan-Meier analysis with log-rank tests. Statistical tests were two-sided.

RESULTS

Patients in the two arms did not differ in demographics or history of intravesical therapy. Dysuria occurred more frequently in the optimized arm but did not lead to more frequent treatment termination. In an intent-to-treat analysis, patients in the optimized arm showed a longer median time to recurrence (29.1 months; 95% confidence interval [CI] = 14.0 to 44.2 months) and a greater recurrence-free fraction (41.0%; 95% CI = 30.9% to 51.1%) at 5 years than patients in the standard arm (11.8 months; 95% CI = 7.2 to 16.4 months) and 24.6% (95% CI = 14.9% to 34.3%) (P =.005, log-rank test for time to recurrence). Improvements were found in all risk groups defined by tumor stage, grade, focality, and recurrence.

CONCLUSIONS

This study identified a pharmacologically optimized intravesical mitomycin C treatment with statistically significantly enhanced efficacy.

Treatment of superficial bladder cancer with intravesical chemotherapy

Proper care of patients with superficial bladder cancer requires the assessment of multiple factors, including an understanding of the natural history of this disease, accurate clinical staging, and the expected efficacy of each drug. The pharmacology of intravesical mytomycin C is discussed in detail, as many of this drug's pharmacological principles are applicable to all intravesical chemotherapeutic agents, including doxorubicin, thiotepa, bacillus Calmette-Guérin, epirubicin, and ethoglucid. The bladder wall, bladder cavity, chemical properties of intravesical chemotherapeutic agents, and tumor considerations are discussed. Suggestions based on pharmacological studies are presented to optimize the efficacy of intravesical chemotherapy.

Intravesical epirubicin in the prophylaxis of superficial bladder cancer

Forty-five patients who underwent transurethral resection (TUR) for Ta-T1 superficial bladder cancer were included in the study. Fourteen patients who had TUR alone were assigned to the control group. Epirubicin therapy was started two weeks after complete TUR of the tumour. Epirubicin in a dose of 50 mg diluted in 50 ml saline was installed weekly for 8 weeks in the epirubicin group. The mean follow-up was 24 months. Although recurrence rate was higher in the control group (64.2% versus 32.2%), it was not found to be statistically significant (p = 0.0914, chi-square test). Tumour-free intervals in patients with recurrent disease were significantly longer in the epirubicin group (p < 0.05, Mann-Whitney U-test).

IN CONCLUSION

intravesical epirubicin therapy, which both reduces recurrence rate and prolongs time to recurrence, was found to be effective in the prophylaxis of superficial bladder cancer.