Mesna--a short review

Mechanism of action and impact of thiol homeostasis on efficacy of an enzyme replacement therapy for classical homocystinuria

Homocystinuria (HCU) due to cystathionine beta-synthase (CBS) deficiency is characterized by elevated plasma and tissue homocysteine levels. There is no cure, but HCU is typically managed by methionine/protein restriction and vitamin B6 supplementation. Enzyme replacement therapy (ERT) based on human CBS has been developed and has shown significant efficacy correcting HCU phenotype in several mouse models by bringing plasma total homocysteine below the clinically relevant 100 μM threshold. As the reactive nature of homocysteine promotes disulfide formation and protein binding, and ERT is unable to normalize plasma total homocysteine levels, the mechanism of action of ERT in HCU remains to be further characterized. Here we showed that only a reduced homocysteine serves as a substrate for CBS and its availability restricts the homocysteine-degrading capacity of CBS. We also demonstrated that cells export homocysteine in its reduced form, which is efficiently metabolized by CBS in the culture medium. Availability of serine, a CBS co-substrate, was not a limiting factor in our cell-based model. Biological reductants, such as N-acetylcysteine, MESNA or cysteamine, increased the availability of the reduced homocysteine and thus promoted its subsequent CBS-based elimination. In a transgenic I278T mouse model of HCU, administration of biological reductants significantly increased the proportion of protein-unbound homocysteine in plasma, which improved the efficacy of the co-administered CBS-based ERT, as evidenced by significantly lower plasma total homocysteine levels. These results clarify the mechanism of action of CBS-based ERT and unveil novel pharmacological approaches to further increase its efficacy.

Mesna Improves Outcomes of Sulfur Mustard Inhalation Toxicity in an Acute Rat Model

Inhalation of high levels of sulfur mustard (SM), a potent vesicating and alkylating agent used in chemical warfare, results in acutely lethal pulmonary damage. Sodium 2-mercaptoethane sulfonate (mesna) is an organosulfur compound that is currently Food and Drug Administration (FDA)-approved for decreasing the toxicity of mustard-derived chemotherapeutic alkylating agents like ifosfamide and cyclophosphamide. The nucleophilic thiol of mesna is a suitable reactant for the neutralization of the electrophilic group of toxic mustard intermediates. In a rat model of SM inhalation, treatment with mesna (three doses: 300 mg/kg intraperitoneally 20 minutes, 4 hours, and 8 hours postexposure) afforded 74% survival at 48 hours, compared with 0% survival at less than 17 hours in the untreated and vehicle-treated control groups. Protection from cardiopulmonary failure by mesna was demonstrated by improved peripheral oxygen saturation and increased heart rate through 48 hours. Additionally, mesna normalized arterial pH and pACO2 Airway fibrin cast formation was decreased by more than 66% in the mesna-treated group at 9 hour after exposure compared with the vehicle group. Finally, analysis of mixtures of a mustard agent and mesna by a 5,5'-dithiobis(2-nitrobenzoic acid) assay and high performance liquid chromatography tandem mass spectrometry demonstrate a direct reaction between the compounds. This study provides evidence that mesna is an efficacious, inexpensive, FDA-approved candidate antidote for SM exposure. SIGNIFICANCE STATEMENT: Despite the use of sulfur mustard (SM) as a chemical weapon for over 100 years, an ideal drug candidate for treatment after real-world exposure situations has not yet been identified. Utilizing a uniformly lethal animal model, the results of the present study demonstrate that sodium 2-mercaptoethane sulfonate is a promising candidate for repurposing as an antidote, decreasing airway obstruction and improving pulmonary gas exchange, tissue oxygen delivery, and survival following high level SM inhalation exposure, and warrants further consideration.

Insights into the biotechnology potential of Methanosarcina

Methanogens are anaerobic archaea which conserve energy by producing methane. Found in nearly every anaerobic environment on earth, methanogens serve important roles in ecology as key organisms of the global carbon cycle, and in industry as a source of renewable biofuels. Environmentally, methanogenic archaea play an essential role in the reintroducing unavailable carbon to the carbon cycle by anaerobically converting low-energy, terminal metabolic degradation products such as one and two-carbon molecules into methane which then returns to the aerobic portion of the carbon cycle. In industry, methanogens are commonly used as an inexpensive source of renewable biofuels as well as serving as a vital component in the treatment of wastewater though this is only the tip of the iceberg with respect to their metabolic potential. In this review we will discuss how the efficient central metabolism of methanoarchaea could be harnessed for future biotechnology applications.

Analysis of sodium 2-mercaptoethane sulfonate in rat plasma using high performance liquid chromatography tandem-mass spectrometry

Sodium 2-mercaptoethane sulfonate (MESNA) is a thiol-containing compound that has proven to be effective in inactivating acrolein, the toxic metabolite of some anti-cancer drugs (e.g., cyclophosphamide and ifosphamide). Also, it scavenges free radicals which cause numerous disorders by attacking biological molecules. Current methods available to analyze MESNA in biological matrices include colorimetry and high-performance liquid chromatography (HPLC) with ultraviolet, fluorescence, or electrochemical detection. These methods have several limitations including low sensitivity, poor selectivity, a high degree of difficulty, and long analysis times. Hence, a rapid, simple, and sensitive HPLC tandem mass spectrometry (MS/MS) method was developed and validated to quantify MESNA in rat plasma following IP administration. The analysis of MESNA was accomplished via plasma protein precipitation, centrifugation, supernatant evaporation, reconstitution, and HPLC-MS/MS analysis. The method showcases an outstanding limit of detection (20 nM), excellent linearity (R² = 0.999, and percent residual accuracy >90%) and a wide linear range (0.05-200 μM). The method also produced good accuracy and precision (100 ± 10% and <10% relative standard deviation, respectively). The validated method was successfully used to analyze MESNA from treated animals and will allow easier development of MESNA for therapeutic purposes.

Oxidative Stress and Cognitive Alterations Induced by Cancer Chemotherapy Drugs: A Scoping Review

Cognitive impairment is one of the most deleterious effects of chemotherapy treatment in cancer patients, and this problem sometimes remains even after chemotherapy ends. Common classes of chemotherapy-based regimens such as anthracyclines, taxanes, and platinum derivatives can induce both oxidative stress in the blood and in the brain, and these effects can be reproduced in neuronal and glia cell cultures. In rodent models, both the acute and repeated administration of doxorubicin or adriamycin (anthracyclines) or cisplatin impairs cognitive functions, as shown by their diminished performance in different learning and memory behavioural tasks. Administration of compounds with strong antioxidant effects such as N-acetylcysteine, gamma-glutamyl cysteine ethyl ester, polydatin, caffeic acid phenethyl ester, and 2-mercaptoethane sulfonate sodium (MESNA) counteract both oxidative stress and cognitive alterations induced by chemotherapeutic drugs. These antioxidant molecules provide the scientific basis to design clinical trials in patients with the aim of reducing the oxidative stress and cognitive alterations, among other probable central nervous system changes, elicited by chemotherapy in cancer patients. In particular, N-acetylcysteine and MESNA are currently used in clinical settings and are therefore attracting scientific attention.

Metabolic-Hydroxy and Carboxy Functionalization of Alkyl Moieties in Drug Molecules: Prediction of Structure Influence and Pharmacologic Activity

Alkyl moieties-open chain or cyclic, linear, or branched-are common in drug molecules. The hydrophobicity of alkyl moieties in drug molecules is modified by metabolic hydroxy functionalization via free-radical intermediates to give primary, secondary, or tertiary alcohols depending on the class of the substrate carbon. The hydroxymethyl groups resulting from the functionalization of methyl groups are mostly oxidized further to carboxyl groups to give carboxy metabolites. As observed from the surveyed cases in this review, hydroxy functionalization leads to loss, attenuation, or retention of pharmacologic activity with respect to the parent drug. On the other hand, carboxy functionalization leads to a loss of activity with the exception of only a few cases in which activity is retained. The exceptions are those groups in which the carboxy functionalization occurs at a position distant from a well-defined primary pharmacophore. Some hydroxy metabolites, which are equiactive with their parent drugs, have been developed into ester prodrugs while carboxy metabolites, which are equiactive to their parent drugs, have been developed into drugs as per se. In this review, we present and discuss the above state of affairs for a variety of drug classes, using selected drug members to show the effect on pharmacologic activity as well as dependence of the metabolic change on drug molecular structure. The review provides a basis for informed predictions of (i) structural features required for metabolic hydroxy and carboxy functionalization of alkyl moieties in existing or planned small drug molecules, and (ii) pharmacologic activity of the metabolites resulting from hydroxy and/or carboxy functionalization of alkyl moieties.

The inhibition of lactoperoxidase catalytic activity through mesna (2-mercaptoethane sodium sulfonate)

Here, we show that mesna (sodium-2-mercaptoethane sulfonate), primarily used to prevent nephrotoxicity and urinary tract toxicity caused by chemotherapeutic agents such as cyclophosphamide and ifosfamide, modulates the catalytic activity of lactoperoxidase (LPO) by binding tightly to the enzyme, functioning either as a one electron substrate for LPO Compounds I and II, destabilizing Compound III. Lactoperoxidase is a hemoprotein that utilizes hydrogen peroxide (H₂O₂) and thiocyanate (SCN^-) to produce hypothiocyanous acid (HOSCN), an antimicrobial agent also thought to be associated with carcinogenesis. Our results revealed that mesna binds stably to LPO within the SCN^- binding site, dependent of the heme iron moiety, and its combination with LPO-Fe(III) is associated with a disturbance in the water molecule network in the heme cavity. At low concentrations, mesna accelerated the formation and decay of LPO compound II via its ability to serve as a one electron substrate for LPO compounds I and II. At higher concentrations, mesna also accelerated the formation of Compound II but it decays to LPO-Fe(III) directly or through the formation of an intermediate, Compound I*, that displays characteristic spectrum similar to that of LPO Compound I. Mesna inhibits LPO's halogenation activity (IC₅₀ value of 9.08 μM) by switching the reaction from a 2e^- to a 1e^- pathway, allowing the enzyme to function with significant peroxidase activity (conversion of H₂O₂ to H₂O without generation of HOSCN). Collectively, mesna interaction with LPO may serve as a potential mechanism for modulating its steady-state catalysis, impacting the regulation of local inflammatory and infectious events.

Prevention of cisplatin-induced hearing loss in children: Informing the design of future clinical trials

Cisplatin is an essential chemotherapeutic agent in the treatment of many pediatric cancers. Unfortunately, cisplatin-induced hearing loss (CIHL) is a common, clinically significant side effect with life-long ramifications, particularly for young children. ACCL05C1 and ACCL0431 are two recently completed Children's Oncology Group studies focused on the measurement and prevention of CIHL. The purpose of this paper was to gain insights from ACCL05C1 and ACCL0431, the first published cooperative group studies dedicated solely to CIHL, to inform the design of future pediatric otoprotection trials. Use of otoprotective agents is an attractive strategy for preventing CIHL, but their successful development must overcome a unique constellation of methodological challenges related to translating preclinical research into clinical trials that are feasible, evaluate practical interventions, and limit risk. Issues particularly important for children include use of appropriate methods for hearing assessment and CIHL severity grading, and use of trial designs that are well-informed by preclinical models and suitable for relatively small sample sizes. Increasing interest has made available new funding opportunities for expanding this urgently needed research.

A Preliminary Clinical Study of Cyclophosphamide with Reduced Glutathione Asc Uroprotector

Reduced glutathione (GSH) has been reported to be an effective protector against cyclophosphamide-induced urotoxicity in experimental models, providing protection comparable to that of mesna. This paper describes our preliminary results of the clinical use of GSH in combination with cyclophosphamide. GSH was administered i.v. in two divided doses of 2.5 g, 15 min before and 30 min after escalating doses of cyclophosphamide ranging from 1.2 up to 1.6 g/m2 (1-h infusion). GSH was well tolerated and did not produce unexpected toxicity. The lack of bladder damage, including microscopic hematuria, supports the protective role of this thiol compound.

Sodium Mercaptoethane Sulfonate Reduces Collagenolytic Degradation and Synergistically Enhances Antimicrobial Durability in an Antibiotic-Loaded Biopolymer Film for Prevention of Surgical-Site Infections

Implant-associated surgical-site infections can have significant clinical consequences. Previously we reported a method for prophylactically disinfecting implant surfaces in surgical pockets, where an antibiotic solution containing minocycline (M) and rifampin (R) was applied as a solid film in a crosslinked biopolymer matrix that partially liquefied in situ to provide extended prophylaxis. Here we studied the effect of adding sodium 2-mercaptoethane sulfonate (MeSNA) on durability of prophylaxis in an in vitro model of implant-associated surgical-site infection. Adding MeSNA to the M/R biopolymer, antimicrobial film extended the duration for which biofilm formation by multidrug-resistant Pseudomonas aeruginosa (MDR-PA) was prevented on silicone surfaces in the model. M/R films with and without MeSNA were effective in preventing colonization by methicillin-resistant Staphylococcus aureus. Independent experiments revealed that MeSNA directly inhibited proteolytic digestion of the biopolymer film and synergistically enhanced antimicrobial potency of M/R against MDR-PA. Incubation of the MeSNA containing films with L929 fibroblasts revealed no impairment of cellular metabolic activity or viability.

Mesna (2-mercaptoethane sodium sulfonate) functions as a regulator of myeloperoxidase

Myeloperoxidase (MPO), an abundant protein in neutrophils, monocytes, and macrophages, is thought to play a critical role in the pathogenesis of various disorders ranging from cardiovascular diseases to cancer. We show that mesna (2-mercaptoethanesulfonic acid sodium salt), a detoxifying agent, which inhibits side effects of oxazaphosphorine chemotherapy, functions as a potent inhibitor of MPO; modulating its catalytic activity and function. Using rapid kinetic methods, we examined the interactions of mesna with MPO compounds I and II and ferric forms in the presence and absence of chloride (Cl^-), the preferred substrate of MPO. Our results suggest that low mesna concentrations dramatically influenced the build-up, duration, and decay of steady-state levels of Compound I and Compound II, which is the rate-limiting intermediate in the classic peroxidase cycle. Whereas, higher mesna concentrations facilitate the porphyrin-to-adjacent amino acid electron transfer allowing the formation of an unstable transient intermediate, Compound I*, that displays a characteristic spectrum similar to Compound I. In the absence of plasma level of chloride, mesna not only accelerated the formation and decay of Compound II but also reduced its stability in a dose depend manner. Mesna competes with Cl^-, inhibiting MPO's chlorinating activity with an IC₅₀ of 5µM, and switches the reaction from a 2e^- to a 1e^- pathway allowing the enzyme to function only with catalase-like activity. A kinetic model which shows the dual regulation through which mesna interacts with MPO and regulates its downstream inflammatory pathways is presented further validating the repurposing of mesna as an anti-inflammatory drug.

Mechanistic study of BNP7787-mediated cisplatin nephroprotection: modulation of gamma-glutamyl transpeptidase

PURPOSE

The mechanisms for cisplatin-induced renal cell injury have been the focus of intense investigation for many years with a view to provide a more effective and convenient form of nephroprotection. BNP7787 (disodium 2,2'-dithio-bis ethane sulfonate; dimesna, Tavocept), is a water-soluble disulfide investigational new drug that is undergoing clinical development for the prevention and mitigation of clinically important chemotherapy-induced toxicities associated with platinum-type chemotherapeutic agents. We hypothesized that part of BNP7787's mechanism of action (MOA) pertaining to the potential prevention of cisplatin-induced nephrotoxicity involves the inhibition of gamma-glutamyl transpeptidase (GGT) activity, mediated by BNP7787-derived mesna-disulfide heteroconjugates that contain a terminal gamma-glutamate moiety [e.g., mesna-glutathione (MSSGlutathione) and mesna-cysteinyl-glutamate (MSSCE)].

METHODS

Inhibition studies were conducted on human and porcine GGT to determine the effect of mesna-disulfide heteroconjugates on the enzyme's activity in vitro. These studies utilized a fluorimetric assay that monitored the hydrolysis of L-gamma-glutamyl-7-amino-4-trifluoromethylcoumarin (GG-AFC) to AFC.

RESULTS

Mesna-disulfide heteroconjugates that contained gamma-glutamyl moieties were potent inhibitors of human and porcine GGT. An in situ-generated mesna-cisplatin conjugate was not a substrate for GGT.

CONCLUSIONS

The GGT xenobiotic metabolism pathway is postulated to be a major toxification pathway for cisplatin nephrotoxicity, and BNP7787 may play a novel and critical therapeutic role in the modulation of GGT activity. We further postulate that there are two general mechanisms for BNP7787-mediated nephroprotection against cisplatin-induced nephrotoxicity involving this pathway. First, the active BNP7787 pharmacophore, mesna, produces an inactive mesna-cisplatin conjugate that is not a substrate for the GGT toxification pathway (GGT xenobiotic metabolism pathway) and, second, BNP7787-derived mesna-disulfide heteroconjugates may serve as selective, potent inhibitors of GGT, possibly resulting in nephroprotection by a novel means.

Antioxidant status in pediatric acute lymphocytic leukemia (ALL) and solid tumors: the impact of oxidative stress

BACKGROUND

Pediatric ALL patients are subjected to an aggressive and continuous chemotherapy protocol, while solid tumor patients have a less intensive treatment. We studied the antioxidant status of children from the two groups and hypothesized that the antioxidant status will differ in concert with their treatment.

PROCEDURE

The antioxidant status in plasma of seven ALL children and that of six children treated for different solid tumors, in regard to the different treatment regimen, was compared with healthy controls. These samples were taken during therapy, just before the next cyclophosphamide treatment, to determine the accumulative oxidative stress.

RESULTS

Children from the ALL group (n = 7) had significantly lower thiol plasma levels than controls (P < 0.01) and their antioxidant capacity as measured by the ferric reducing ability of plasma (FRAP) was significantly lower (P < 0.01). These parameters were normal in the solid tumors group (n = 6) but plasma antioxidant capacity as measured by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was significantly lower (P < 0.01).

CONCLUSIONS

Both groups had impaired plasma antioxidant status. The higher oxidative stress of children with ALL is associated with the protocol for treating ALL which is much more aggressive and frequent than that of the solid tumors. The lower antioxidant status in plasma with ALL children is probably associated with increased reactive oxygen species (ROS) as indicated by the decrease of the antioxidant activity. This oxidative stress may lead to cell death or greater sensitivity of the tumor cell to therapy, with better outcome for pediatric patients with ALL.

The pharmacologic basis of ifosfamide use in adult patients with advanced soft tissue sarcomas

The treatment outcome of patients with locally advanced and metastatic soft tissue sarcomas is poor. Doxorubicin is regarded as standard treatment, but its use is featured by the occurrence of cardiotoxicity. This hinders the administration of this drug at high doses or in combination with, in theory, attractive newly developed targeted drugs, such as vascular endothelial growth factor (VEGF) pathway inhibitors. The combination of doxorubicin and VEGF pathway inhibitors has been shown to yield an unacceptable high rate of cardiomyopathy. Ifosfamide is the only drug that consistently shows response rates comparable to those of doxorubicin. The lack of cardiotoxicity renders this drug a much more attractive alternative than doxorubicin to be explored at high doses or as part of new drug combinations. This review addresses the clinical pharmacology, metabolism, and present role of ifosfamide in the treatment of locally advanced and/or metastatic soft tissue sarcomas, excluding gastrointestinal stromal tumors, the Ewing-like sarcomas, and other small blue round cell tumors. Furthermore, this review focuses on the anticipated growing role of ifosfamide in the development of new treatment strategies.

Pharmacokinetics of BNP7787 and its metabolite mesna in plasma and ascites: a case report

PURPOSE

BNP7787 (2',2'-dithio-bis-ethane sulfonate sodium) is a novel protector against cisplatin-induced toxicities. The pharmacokinetics of BNP7787 and its metabolite mesna were investigated in plasma and ascites of a cancer patient. We also evaluated potential pharmacokinetic interactions between BNP7787 and cisplatin.

METHODS

BNP7787 and mesna were measured as mesna in deproteinized plasma and ascites using high-performance liquid chromatography with an electrochemical detector provided with a wall-jet gold electrode.

RESULTS

After the i.v. administration of 41 g/m(2) BNP7787, BNP7787 and mesna had a half-life of 1.5 and 3.4 h, respectively. The AUC( infinity ) of mesna was approximately 8% of the AUC( infinity ) of BNP7787. Coadministration of cisplatin did not appear to influence the plasma concentration-time curves of BNP7787 and mesna. In ascites, approximately 0.02% of the BNP7787 dose was present as mesna, whereas approximately 4% of the dose was present as BNP7787 at the time of the maximum concentration.

CONCLUSIONS

It can be concluded that the presence of ascites did not have a major impact on the pharmacokinetics of BNP7787 and coadministration of cisplatin did not influence the pharmacokinetics of BNP7787 and mesna.

Chemically assisted dissection of tissues in laparoscopic excision of endometriotic cysts

STUDY OBJECTIVE

To evaluate the capacity of chemical dissection of tissues using a mucolytic substance, Mesna, in improving laparoscopic excision of endometriotic cysts.

DESIGN

Randomized, double-blind, controlled trial (Canadian Task Force classification I).

SETTING

University-affiliated training hospital.

PATIENTS

Forty-four women with symptomatic ovarian endometriotic cysts. Intervention. Laparoscopic excision of endometriotic cysts in 22 women with the aid of Mesna solution and in 22 with the aid of saline solution.

MEASUREMENTS AND MAIN RESULTS

In comparison with saline solution, Mesna as a chemical dissector resulted in significant reductions in operating time, in difficulty encountered by the surgeon to enucleate the cysts, and in less bleeding. No differences were found in length of hospital stay, costs of surgeries, analgesic requirement, and fever. Postoperatively, patients treated with Mesna achieved more pregnancies than those treated with saline.

CONCLUSION

Chemical dissection of tissues with Mesna proved to be a safe and suitable support in laparoscopic surgery for ovarian endometriotic cysts.

Polysulfonates derived from metal thiolate complexes as inhibitors of HIV-1 and various other enveloped viruses in vitro

Sodium 2-mercaptoethanesulfonate reacts with the metal ions Pd(II), Pt(II), Ag(I), Cd(II) and Zn(II) to yield complexes containing multiple anionic sulfonate sites. On the basis of spectroscopic and other analytical data the complexes were assigned the tentative molecular formulas: Pd6(SCH2CH2SO3Na)12, Ptn(SCH2CH2SO3Na)2n+2, Agn(SCH2CH2SO3Na)n, Na2Zn4(SCH2CH2SO3Na)10, and Na2Cd4(SCH2CH2SO3Na)10. The complexes displayed a variety of differences in activity towards DNA and RNA viruses. The platinum complex showed no measurable cytotoxicity and exhibited a spectrum of antiviral activity resembling that of dextran sulfate. It was active against HIV-1 and HIV-2, herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), thymidine kinase-deficient HSV-1, human cytomegalovirus, vesicular stomatitis virus (VSV), influenza A virus, respiratory syncytial virus (RSV), Sindbis virus, Junin virus and Tacaribe virus. The palladium complex also showed no measurable cytotoxicity, but was completely inactive against most viruses, with one notable exception: both HIV-1 and HIV-2 were substantially inhibited by the palladium complex. The silver complex showed significantly less antiviral activity and greater cytotoxicity than the platinum complex but did show some selectivity against RSV. The zinc complex showed only modest activity against VSV, RSV, Junin virus, and Tacaribe virus, and like the silver compound was more cytotoxic than either the platinum or palladium complex. The cadmium complex was toxic to all of the cell lines used for in vitro evaluation of antiviral activity. Based on these results, the platinum and palladium compounds appear to be promising candidates for further studies, that is, as vaginal microbicides in the prevention of genital HIV and/or HSV transmission.

Identification of coenzyme M biosynthetic phosphosulfolactate synthase: a new family of sulfonate-biosynthesizing enzymes

The hyperthermophilic euryarchaeon Methanococcus jannaschii uses coenzyme M (2-mercaptoethanesulfonic acid) as the terminal methyl carrier in methanogenesis. We describe an enzyme from that organism, (2R)-phospho-3-sulfolactate synthase (ComA), that catalyzes the first step in coenzyme M biosynthesis. ComA catalyzed the stereospecific Michael addition of sulfite to phosphoenolpyruvate over a broad range of temperature and pH conditions. Substrate and product analogs moderately inhibited activity. This enzyme has no significant sequence similarity to previously characterized enzymes; however, its Mg(2+)-dependent enzyme reaction mechanism may be analogous to one proposed for enolase. A diverse group of microbes and plants have homologs of ComA that could have been recruited for sulfolactate or sulfolipid biosyntheses.

Quantification of BNP7787 (dimesna) and its metabolite mesna in human plasma and urine by high-performance liquid chromatography with electrochemical detection

A sensitive and accurate assay was developed and validated to determine BNP7787 (dimesna), a new protector against cisplatin-induced toxicities, and its metabolite mesna in plasma and urine of patients. Both analytes were measured as mesna in deproteinized plasma or in urine diluted with mobile phase using high-performance liquid chromatography with an electrochemical detector provided with a wall-jet gold electrode. The assays for BNP7787 and mesna in deproteinized plasma were linear over the range of 1.6-500 microM and 0.63-320 microM, respectively. In plasma, the mean recovery of BNP7787 over the whole concentration range was 100.6% and of mesna 94.6%. The lower limits of quantitation (LLQs) of BNP7787 and mesna in deproteinized plasma were 1.6 microM and 0.63 microM, respectively. For both compounds the within- and between-day accuracy and precision of the assay was better than 12%. The assays for BNP7787 and mesna in urine were linear over the range of 0.8-1200 microM and 0.63-250 microM, respectively. In urine, the mean recovery of BNP7787 over the whole concentration range was 94.1% and of mesna 93.1%. The LLQ of BNP7787 in urine was 0.8 microM and of mesna 1.6 microM. The within- and between-day accuracy and precision of the assay for BNP7787 and mesna was lower than 15%. The stability of mesna in urine increased with an increasing concentration of mesna, lower temperature and addition of EDTA (1 g/l) and hydrochloric acid (0.2 M). BNP7787 in urine was stable for at least 24 h at temperatures in the range of -20 degrees C up to 37 degrees C and independent of the concentration. The developed assays are currently applied for samples of patients with solid tumors participating in a phase I trial of BNP7787 in combination with cisplatin.

Clinical pharmacokinetics and pharmacodynamics of ifosfamide and its metabolites

This review discusses several issues in the clinical pharmacology of the antitumour agent ifosfamide and its metabolites. Ifosfamide is effective in a large number of malignant diseases. Its use, however, can be accompanied by haematological toxicity, neurotoxicity and nephrotoxicity. Since its development in the middle of the 1960s, most of the extensive metabolism of ifosfamide has been elucidated. Identification of specific isoenzymes responsible for ifosfamide metabolism may lead to an improved efficacy/toxicity ratio by modulation of the metabolic pathways. Whether ifosfamide is specifically transported by erythrocytes and which activated ifosfamide metabolites play a key role in this transport is currently being debated. In most clinical pharmacokinetic studies, the phenomenon of autoinduction has been observed, but the mechanism is not completely understood. Assessment of the pharmacokinetics of ifosfamide and metabolites has long been impaired by the lack of reliable bioanalytical assays. The recent development of improved bioanalytical assays has changed this dramatically, allowing extensive pharmacokinetic assessment, identifying key issues such as population differences in pharmacokinetic parameters, differences in elimination dependent upon route and schedule of administration, implications of the chirality of the drug and interpatient pharmacokinetic variability. The mechanisms of action of cytotoxicity, neurotoxicity, urotoxicity and nephrotoxicity have been pivotal issues in the assessment of the pharmacodynamics of ifosfamide. Correlations between the new insights into ifosfamide metabolism, pharmacokinetics and pharmacodynamics will rationalise the further development of therapeutic drug monitoring and dose individualisation of ifosfamide treatment.

Chemically assisted dissection of tissues: an interesting support in abdominal myomectomy

BACKGROUND

The aim of this study was to verify the efficacy of sodium-2-mercaptoethanesulfonate (mesna) in the chemical separation of tissues in abdominal myomectomies when used with the traditional mechanical separation techniques.

STUDY DESIGN

In a prospective, randomized study, 58 women underwent abdominal myomectomy. In 29 of these, we used mesna for highlighting and separating tissues, and in the other 29 we used saline solution for the same purposes. The variables evaluated included the number of myomas removed, the volume of the biggest myoma, and the total volume of the myomas removed in every intervention. We also recorded operating time, the length of hospital stay, the degree of procedure difficulty, perioperative blood loss, operative complications, and cost.

RESULTS

The operation was significantly shorter in the mesna group (p < 0.05) even though the volume and the number of myomas were larger. The degree of difficulty evaluated by the surgeon at the end of every operation was not significantly different in the two groups. The reduction in hemoglobin 24 hours after operation was significantly less in the patients treated with mesna (p = 0.006), but this difference was probably altered by the increase in hematocrit levels.

CONCLUSIONS

Because of its ability as a chemical dissector, mesna may be a useful aid in this type of benign gynecologic operation. Larger studies to confirm this are needed.

Mechanistic aspects of the cytotoxic activity of glufosfamide, a new tumour therapeutic agent

Beta-D-glucosyl-ifosfamide mustard (D 19575, glc-IPM, INN = glufosfamide) is a new agent for cancer chemotherapy. Its mode of action, which is only partly understood, was investigated at the DNA level. In the breast carcinoma cell line MCF7 glufosfamide inhibited both the synthesis of DNA and protein in a dose-dependent manner, as shown by the decreased incorporation of [3H-methyl]-thymidine into DNA and [14C]-methionine into protein of these cells. Treatment of MCF7 cells with 50 microM glufosfamide was sufficient to trigger poly(ADP-ribose) polymerase (PARP) activation, as revealed by immunofluorescence analysis. Both CHO-9 cells, which are O6-methylguanine-DNA methyltransferase (MGMT)-deficient, and an isogenic derivative, which has a high level of MGMT, showed the same cytotoxic response to beta-D-glc-IPM, indicating that the O6 position of guanine is not the critical target for cytotoxicity. By contrast, a sharp decrease in survival of cross-link repair deficient CL-V5 B cells was observed already at concentrations of 0.1 mM beta-D-glc-IPM, whereas the wild-type V79 cells showed a 90% reduction in survival only after treatment with 0.5 mM of this compound. The therapeutically inactive beta-L-enantiomer of glufosfamide also showed genotoxic effects in the same assays but at much higher doses. This was probably due to small amounts of ifosfamide mustard formed under the conditions of incubation. The results indicate that the DNA crosslinks are the most critical cytotoxic lesions induced by beta-D-glc-IPM.

Saturable metabolism of continuous high-dose ifosfamide with mesna and GM-CSF: a pharmacokinetic study in advanced sarcoma patients. Swiss Group for Clinical Cancer Research (SAKK)

BACKGROUND

The aim of this study was to assess the pharmacology, toxicity and activity of high-dose ifosfamide mesna +/- GM-CSF administered by a five-day continuous infusion at a total ifosfamide dose of 12-18 g/m2 in adult patients with advanced sarcomas.

PATIENTS AND METHODS

Between January 1991 and October 1992 32 patients with advanced or metastatic sarcoma were entered the study. Twenty-seven patients were pretreated including twenty-three with prior ifosfamide at less than 8 g/m2 total dose/cycle. In 25 patients (27 cycles) extensive pharmacokinetic analyses were performed.

RESULTS

The area under the plasma concentration-time curve (AUC) for ifosfamide increased linearly with dose while the AUC's of the metabolites measured in plasma by thin-layer chromatography did not increase with dose, particularly that of the active metabolite isophosphoramide mustard. Furthermore the AUC of the inactive carboxymetabolite did not increase with dose. Interpatient variability of pharmacokinetic parameters was high. Dose-limiting toxicity was myelosuppression at 18 g/m2 total dose with grade 4 neutropenia in five of six patients and grade 4 thrombocytopenia in four of six patients. Therefore the maximum tolerated dose was considered to be 18 g/m2 total dose. There was one CR and eleven PR in twenty-nine evaluable patients (overall response rate 41%).

CONCLUSION

Both the activation and inactivation pathways of ifosfamide are non-linear and saturable at high-doses although the pharmacokinetics of the parent drug itself are dose linear. Ifosfamide doses greater than 14-16 g/m2 per cycle appear to result in a relative decrease of the active metabolite isophosphoramide mustard. These data suggest a dose-dependent saturation or even inhibition of ifosfamide metabolism by increasing high dose ifosfamide and suggest the need for further metabolic studies.

Ifosfamide-induced stomatocytosis and mesna-induced echinocytosis: influence on biorheological properties of blood

Ifosfamide is an alkylating agent which has poorly understood toxic side effects such as encephalopathy. We hypothesized that ifosfamide and concomitantly applied mesna could have an influence on the flow properties of blood, and thus carried out an in vitro study. Whole blood was incubated in vitro with increasing concentrations of ifosfamide (0-50 mg/ml), mesna (0-20 mg/ml) and combinations thereof. Chloroacetaldehyde, a major metabolite of ifosfamide, was also studied (0-5 mmol/l). Ifosfamide led to a dose-dependent stomatocytic shape transformation and mesna to an echinocytic shape transformation of erythrocytes. These shape changes were reversible upon removal of the causing agent. Both shape changes increased whole blood viscosity. Erythrocyte aggregation was decreased by both drugs at high concentration. Erythrocyte deformability, as measured with the transit time through 5-microm pores, was decreased by mesna and remained unaffected by ifosfamide. These effects were seen at concentrations which may be reached in vivo at the infusion site of the drugs into a vein and in the urinary tract. We conclude that ifosfamide and mesna interact with the lipid bilayer of the cell membrane, which may contribute to the toxicity of the compounds.

Pharmacokinetics of ifosfamide administered according to three different schedules in metastatic soft tissue and bone sarcomas

Ifosfamide is a leading drug in soft tissue sarcoma therapy. Recently high dose therapy (>9 g/m2) has been introduced in different schemes to obtain a higher response rate. All these higher doses can be administered following two different schedules: continuous infusion 24 hours a day for 4-5 days or bolus administration for 5 consecutive days. In this study we compare the differences in the pharmacokinetic profile between the two schedules. In both schemes we saw a very important autoinduction phenomenon, with a corresponding half-life decrease and total body clearance increase during the days of therapy. The clearances were not directly correlated with the administered dose. We can conclude that ifosfamide continuous infusion therapy is equivalent to fractionated administration, at least from a pharmacokinetic point of view. Short-term infusion is subjectively better tolerated and is therefore preferred.

Efficacy of mesna for prevention of hemorrhagic cystitis after high-dose cyclophosphamide therapy

For these reasons, a definitive statement about the relative efficacy of mesna for prophylaxis of cyclophosphamide-associated HC in BMT patients cannot be made. Because HC is a frequent and potentially serious complication of high-dose cyclophosphamide therapy, the implementation of some preventive measure is mandatory in all patients. Unless medically contraindicated, provision of sufficient hydration and diuresis to maintain adequate high urine flow should be a component of all prophylactic regimens. It is unclear whether the addition of mesna therapy or bladder irrigation to intravenous hydration provides greater protection. Studies indicate that mesna probably has no adverse effect on engraftment. This is consistent with its chemistry and pharmacology, as the drug is hydrophilic and activated only in the kidneys. Thus, it is inactive in the bloodstream and unable to penetrate cell membranes and interfere with the action of cyclophosphamide. Although safety issues surrounding the use of mesna for prevention of cyclophosphamide-associated HC appear to have been resolved, efficacy issues must await the completion of further well-controlled comparative trials.

Effect of stereochemistry on the oxidative metabolism of the cyclophosphamide metabolite aldophosphamide

31P NMR and cell perfusion techniques were used to investigate the conversion of the individual enantiomers of aldophosphamide (AP) to carboxyphosphamide (CBP) as catalyzed by aldehyde dehydrogenase in human erythroleukemia K562 cells. R- and S-cyclophosphamides (CPs) were treated with ozone and hydrogen peroxide to yield Rp- and Sp-cis-4-hydroperoxycyclophosphamides (Rp- and Sp-cis-4-HO2-CP); reduction of each hydroperoxide gave the corresponding enantiomer of AP [along with its tautomer 4-hydroxycyclophosphamide (4-HO-CP)]. In separate experiments, K562 cells embedded in agarose gel threads were perfused at pH 7.4, 21 +/- 1 degrees, with solutions of 1.4 mM Rp- and Sp-4-HO-CP/AP, both with and without added mesna (an acrolein scavenger). A comparison of the 31P NMR spectral data derived from the experiments revealed little statistical difference (+/- 10-20% error limits) in the normalized intensities of the CBP peaks arising from the individual AP enantiomers [with added mesna, the ratio Rp-CBP:Sp-CBP was 1.00:1.24 +/- 0.13 (average deviation); without mesna, the same ratio was 1.00:1.35]. Using conventional methods for evaluating the in vitro drug toxicities, CP-resistant L1210 cells were treated in separate experiments with Rp- and Sp-cis-4-HO2-CP; there were no significant differences between the toxicities exhibited by the stereoisomers.

A prospective randomized evaluation of three schedules of mesna administration in patients receiving an ifosfamide-containing chemotherapy regimen: sustained efficiency and simplified administration

Chemotherapy with oxazaphosphorines, such as ifosfamide, is often limited by unacceptable urotoxicity. Without uroprotection hemorrhagic cystitis becomes dose-limiting. Mesna, a thiol compound, is a drug able to bind the toxic metabolites, forming nontoxic compounds in the urine. A total of 122 patients were enrolled in this study and 228 chemotherapy cycles with an ifosfamide-containing regimen were performed (225 evaluable). Mesna was given at the same total dose as the ifosfamide in all arms. On arm A, mesna was given i. v. in equal doses 15 min before and 4 h and 8 h following the ifosfamide dose. On arm B, mesna was given in three equivalent doses 15 min before (i.v.) and 4 h (i.v.) and 8 h (p.o., double dose) following ifosfamide. On arm C, mesna was given i.v. in two equal doses given 15 min before and 4 h following. The incidence of urotoxicity was very low (lower than 15%) in the three arms, 0% in A, 1.36% in B and 2.70% in C. All three arms were equally efficient. Schedule C was considered superior to the others, since it was equally effective, simpler and more convenient.

Phase II clinical trial of carboplatin, ifosfamide, with oral mesna for metastatic breast carcinoma

Twenty-five women with advanced breast carcinoma refractory to first-line chemotherapy entered a phase II trial to evaluate the efficacy of ifosfamide and carboplatin. Additionally the trial assessed the clinical usefulness of oral 2-mercaptoethane sulfonate (mesna) for urothelial protection. Two partial remissions were observed (8%); toxicity was significant but acceptable, with no treatment-related deaths. The combination of ifosfamide and carboplatin had little activity as the second-line treatment in our population of patients with heavily pretreated metastatic breast cancer. Oral mesna was effective for urothelial protection, permitting outpatient administration of ifosfamide.

Dithio-bis-mercaptoethanesulphonate (DIMESNA) does not prevent cellular damage by metabolites of ifosfamide and cyclophosphamide in LLC-PK1 cells

Ifosfamide (IF) is an alkylating cytostatic with urotoxic (haemorrhagic cystitis) and nephrotoxic (Fanconi syndrome) side effects. Cyclophosphamide (CP), a structural isomer of IF, shows urotoxic but no nephrotoxic side effects. The development of haemorrhagic cystitis during therapy with IF or CP can be prevented by the uroprotective drug sodium-2-mercaptoethanesulphonate (MESNA). However, even in the presence of MESNA, Fanconi syndrome may still develop after therapy with IF. Using the renal tubular cell line LLC-PK1, we investigated whether there is a protective effect of either MESNA or of its major metabolite DIMESNA, in combination with metabolites of IF or CP, on thymidine incorporation, uridine incorporation or total protein. DIMESNA, the dimer of MESNA, is the dominant form of the molecule in the circulation; the proximal tubular cell must convert this back to MESNA at the expense of glutathione, before it can exert its uroprotective action. We did not find a protective effect of DIMESNA under any of the experimental conditions tested. LLC-PK1 cells exposed to 3 mmol/l DIMESNA did not convert DIMESNA to MESNA. The toxic effect of the CP metabolite 4-OOH-CP was more pronounced in the presence of DIMESNA than in its absence. MESNA completely prevented the toxic effects of acrolein and of 4-OOH-CP. The toxic effects of 4-OOH-IF and of chloracetaldehyde, two major metabolites of IF, were significantly reduced in the presence of MESNA. However, even at 30-fold molar excess of MESNA over a 4-OOH_IF, thymidine incorporation remained reduced by 40% compared with controls, indicating incomplete protection of tubular cells against metabolites of IF. Similarly, the effect of chloracetaldehyde was not completely reversed by MESNA.(ABSTRACT TRUNCATED AT 250 WORDS)

The anti-tumour activity of ifosfamide on heterotransplanted testicular cancer cell lines remains unaltered by the uroprotector mesna

Ifosfamide is clinically used in combination chemotherapy regimens for the treatment of patients with high-grade lymphomas, sarcomas and metastatic germ cell tumours. In order to reduce the oxazophosphorine-related urothelial toxicity, sodium mercaptoethane sulphonate (mesna) is used in different schedules following the administration of ifosfamide. The proposed mechanism of mesna activity is the binding of toxic oxazaphosphorine metabolites such as acrolein in the urine of the patients. Since an influence of mesna on ifosfamide anti-tumour activity is controversial, the current study has used xenografts from two human testicular cancer cell lines heterotransplanted into nude mice to study the anti-tumour activity of ifosfamide in combination with different dosages and schedules of mesna. In both human testicular cancer cell lines, H 12.1 and 2102 EP, ifosfamide demonstrated anti-tumour activity as a single agent. No reduction in ifosfamide activity was observed with the application of mesna at a dose range from 50% to 200% of the ifosfamide dose. Furthermore, the application of mesna before and 3 h after ifosfamide, a schedule used in many clinical protocols because of the short half life of mesna, not only maintained high ifosfamide anti-tumour activity but also seemed to be associated with the lower systemic and urothelial toxicity of ifosfamide therapy compared with ifosfamide given alone. In conclusion, the experimental in vivo system using human heterotransplanted testicular cancer cell lines confirms the significant anti-tumour activity of ifosfamide in malignant germ cell tumours and demonstrates that mesna does not impair ifosfamide anti-tumour activity in this model. These results are most likely transferable to the use of mesna in patients with metastatic testicular cancer.

Toxicity of ifosfamide, cyclophosphamide and their metabolites in renal tubular cells in culture

Ifosfamide (IF) and cyclophosphamide (CP) are highly effective alkylating cytostatic drugs. IF and CP have to be activated through a metabolic step in vivo; numerous metabolites are known. While both IF and its structural isomer CP have severe urotoxic side effects, only IF is also a nephrotoxic drug, causing tubular damage resulting in Fanconi syndrome in some cases. Little information is available regarding the pathogenic mechanism of tubular damage by IF. We used the renal epithelial cell line LLC-PK1, which has many properties of the proximal tubule, in order to investigate the toxicity of IF and CP and of their reactive metabolites 4-hydroxy-IF (4-OH-IF), 4-hydroxy-CP (4-OH-CP), acrolein and chloroacetaldehyde (CAA). Protein content of monolayers, DNA and RNA synthesis were determined by standard techniques (thymidine and uridine incorporation). IF and CP had the lowest toxicities of all compounds tested. Both drugs inhibited thymidine incorporation by about 30% at a concentration of 300 mumol/l after 1 h incubation. 4-OH-IF and 4-OH-CP were significantly more toxic than the parent drugs. Thymidine incorporation, the most sensitive parameter, was reduced by about 70% by 300 mumol/l of either compound. In addition, 4-OH-CP reduced the total protein content of monolayers. 4-OH-IF did not effect protein content and RNA synthesis. Acrolein, the most toxic metabolite tested, reduced all three parameters significantly at concentrations of 50-75 mumol/l after 1 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Ifosfamide nephrotoxicity in paediatric cancer patients

Ifosfamide is an alkylating agent which has been incorporated into frontline therapy for a number of malignant paediatric tumours. Recent data appears to suggest that tubular dysfunction may result from incorporation of this drug into chemotherapy schedules and that toxicity may be dose related. A detailed investigation of renal function was performed in a group of patients, ranging in age from 8 months to 15.9 years (median 8.6 years) with rhabdomyosarcoma (n = 11) and Ewing's sarcoma (n = 9) who were currently receiving (n = 4) or had completed ifosfamide (n = 16) therapy a mean of 16 months at the time of study. All but one patient demonstrated some degree of renal dysfunction and toxicity did not necessarily appear to be dose related. Implications for incorporation of this agent into future schedules for childhood sarcomas, which can expect to cure more than 60% of such children, must be addressed. The importance of ongoing monitoring is emphasised.

Intracellular accumulation of cytosine arabinoside in murine normal and neoplastic lymphocytes following their exposure to sodium 2-mercaptoethanesulphonate

The effect of mesna on intracellular accumulation of cytosine arabinoside (Ara-C) in murine normal and neoplastic lymphocytes was studied. Simultaneous exposure of cells to mesna at concentrations ranging from 0.25 to 1.0 mM and 3H-Ara-C (40.0 nM) resulted in a strong inhibition of Ara-C uptake in normal lymphocytes. Under the same experimental conditions, mesna did not affect the Ara-C uptake in neoplastic cells (cultured L5178Y mouse leukaemia cells and neoplastically transformed thymus cells). It was found that the inhibitory effect of mesna was not cell cycle-dependent, since mesna reduced the Ara-C uptake in both normal quiescent and PHA-stimulated cells. We therefore concluded that mesna may selectively reduce Ara-C uptake by normal cells in vitro.

Ifosfamide with mesna uroprotection and etoposide in recurrent, refractory acute leukemia in childhood. A Pediatric Oncology Group Study

BACKGROUND

Ifosfamide has previously been shown to be active as a single agent and in combination with doxorubicin, etoposide, and teniposide in pediatric solid tumors and adult acute leukemia. The authors performed a dose-escalation trial of ifosfamide with a fixed dosage of etoposide, with mesna uroprotection, in children with multiply recurrent acute leukemia.

METHODS

Chemotherapy was administered daily for 5 days. Etoposide 100 mg/m2 was followed by ifosfamide at an initial dosage of 1.6 g/m2. The ifosfamide was escalated in 20% increments to the maximum tolerated dosage in cohorts of three patients. Mesna 400 mg/m2 was given immediately before the ifosfamide and then at 3 and 6 hours after ifosfamide in the initial patients. Subsequent patients were treated with mesna 400 mg/m2 just before ifosfamide, and then every 2 hours to a total dosage equal to the ifosfamide dosage.

RESULTS

Forty-four heavily pretreated patients were entered on study. Forty were evaluable for toxicity and 36 for response as well. The maximum tolerated dosage of ifosfamide was 4.0 g/m2/d for 5 days (20 g/m2/course). Overall, 10 patients achieved complete remission, and 3 achieved partial remission. Remissions were brief, although four patients went on to bone marrow transplant while in remission. One patient is still alive.

CONCLUSIONS

The combination of etoposide and ifosfamide with mesna uroprotection showed promising activity in children with multiply recurrent acute leukemia.

Oral bioavailability of mesna tablets

To test the feasibility of uroprotection with sodium 2-mercaptoethane-sulfonate (mesna) in tablet form the bioavailability of mesna tablets was determined in healthy volunteers by HPLC. The area under the plasma concentration-time curve (AUC) of free mesna was significantly lower following oral (110 mumol.l-1 x h-1; 95% CI 98-122) than following i.v. administration of 1.2 g of mesna (201 mumol.l-1 x h-1; 95% CI 158-244). The AUC for total mesna, i.e. dimesna and mixed disulfides, however, were comparable in the two groups, with 628 (539-717) and 772 (713-831) mumol.l-1 x h-1, respectively. The mean residence time was significantly longer following oral mesna, at 79 (76-83) min vs 239 (229-250) min. Following oral mesna 51.1% (46.2-56.0%) of the administered dose was recovered in the urine in 24 h, compared with 60.6 (53.6-67.6)% in 4 h following i.v. mesna, and the average concentration of mesna in the urine exceeded 3 mmol.l-1 for 8 h. The data indicate that mesna in tablet form has an adequate bioavailability for uroprotection and therefore may be preferable to liquid mesna, which has an unpleasant taste. Oral mesna has a longer mean residence time than i.v. mesna, which means that uroprotection can be achieved with longer dosing intervals.

Comparison of N-acetylcysteine and mesna as uroprotectors with ifosfamide combination chemotherapy in refractory germ cell tumors

From January 1983 through August 1988, 318 consecutive patients with refractory germ cell neoplasms were treated with ifosfamide-containing combination chemotherapy. The patients received ifosfamide at 1.2 gm/m2/day with cis-platin 20 mg/m2/day for 5 days and etoposide 75 mg/m2/day for 5 days or vinblastine 0.11 mg/kg on days 1 and 2 for each cycle. Of 277 evaluable patients, NAC was used as an uroprotector in the initial 86 patients while the latter 191 consecutive patients received mesna to reduce urothelial toxicity. Dosages of NAC was 2.0 gm po q 6 hr and for mesna 120 mg/m2 IV push prior to ifosfamide and then 1200 mg/m2/day as continuous infusion of 5 consecutive days. All patients received 3.0 liters of normal saline per day. The number of courses of chemotherapy given in the two groups were similar. Twenty-four of the 86 patients (27.9%) receiving NAC developed hematuria (13 patients - grade 1, 4 patients - grade 2, and 7 patients - grade 3 toxicity). While 8 out of 191 (4.2%) mesna patients developed hematuria (6 - grade 1 and 2 - grade 3) (p < 0.0001). The incidence of severity of renal toxicity was similar in the two groups. Ifosfamide dosage was reduced solely for urothelial toxicity in 11 patients receiving NAC compared with none of the patients receiving mesna (p < 0.0001). Chemotherapy response was similar in the two groups. In conclusion, mesna provides better urothelial protection from ifosfamide-induced toxicity than NAC and allows better maintenance of the drug dosage.

Feasibility and efficacy of arginine 2-mercaptoethanesulfonate (ARGIMESNA) in the prevention of hemorragic cystitis from ifosfamide (IFO)

Tolerability and efficacy of the new uroprotective agent ARGIMESNA was assessed within a randomized cross-over study comparing it to sodiummercaptoethanesulfonate (MESNA), in patients treated with IFO. MESNA i.v., 20% of IFO dose, was given to all patients before chemotherapy; 4 h later, at random, they received ARGIMESNA p.o., 20% of IFO dose every 2 h x 4, or MESNA p.o., 40% of IFO dose every 4 h x 2. Overall, 78 cycles of oral uroprotection were administered: 37 for ARGIMESNA capsules; 41 for MESNA vials p.o. ARGIMESNA was subjectively better tolerated, determining gastro-intestinal discomfort in only 12 out of 37 cycles versus 34/41 of MESNA p.o. (p less than 0.001). Both preparations were equivalent for subjective and objective efficacy since no cycles were complicated by urinary symptoms (dysuria, stranguria, or hematuria). Nevertheless, 2 patients (7.7%) refused further oral assumption of both uroprotectors, whereas MESNA i.v. was added in other 7 patients because of nausea and vomiting caused by chemotherapy. In conclusion, this new oral preparation of mercaptoethanesulfonate turned out to be well tolerated, safe and active in the prevention of haemorrhagic cystitis from IFO.

Ifosfamide/mesna. A review of its antineoplastic activity, pharmacokinetic properties and therapeutic efficacy in cancer

Ifosfamide is an oxazaphosphorine alkylating agent with a broad spectrum of antineoplastic activity. It is a prodrug metabolised in the liver by cytochrome P450 mixed-function oxidase enzymes to isofosforamide mustard, the active alkylating compound. Mesna, a uroprotective thiol agent, is routinely administered concomitantly with ifosfamide, and has almost eliminated ifosfamide-induced haemorrhagic cystitis and has reduced nephron toxicity. Therapeutic studies, mostly noncomparative in nature, have demonstrated the efficacy of ifosfamide/mesna alone, or more commonly as a component of combination regimens, in a variety of cancers. In patients with relapsed or refractory disseminated nonseminomatous testicular cancer, a salvage regimen of ifosfamide/mesna, cisplatin and either etoposide or vinblastine produced complete response in approximately one-quarter of patients. As a component of both induction and salvage chemotherapeutic regimens, ifosfamide/mesna has produced favourable response rates in small cell lung cancer, paediatric solid tumours, non-Hodgkin's and Hodgkin's lymphoma, and ovarian cancer. Induction therapy with ifosfamide/mesna-containing chemotherapeutic regimens has been encouraging in non-small cell lung cancer, adult soft-tissue sarcomas, and as neoadjuvant therapy in advanced cervical cancer. As salvage therapy, ifosfamide/mesna-containing combinations have a palliative role in advanced breast cancer and advanced cervical cancer. Ifosfamide/mesna can elicit responses in patients refractory to numerous other antineoplastic drugs, including cyclophosphamide. With administration of concomitant mesna to protect against ifosfamide-induced urotoxicity, the principal dose-limiting toxicity of ifosfamide is myelosuppression; leucopenia is generally more severe than thrombocytopenia. Reversible CNS adverse effects ranging from mild somnolence and confusion to severe encephalopathy and coma can occur in approximately 10 to 20% of patients after intravenous infusion, and the incidence of neurotoxicity may be increased to 50% after oral administration because of differences in the preferential route of metabolism between the 2 routes of administration. Other adverse effects of ifosfamide include nephrotoxicity, alopecia, and nausea/vomiting. In general, intravenously administered mesna is associated with a low incidence of adverse effects; however, gastrointestinal disturbances are common following oral administration. Thus, ifosfamide/mesna is an important and worthwhile addition to the currently available range of chemotherapeutic agents. It has a broad spectrum of antineoplastic activity and causes less marked myelosuppression than many other cytotoxic agents. At present, the role of ifosfamide/mesna in refractory germ cell testicular cancer is clearly defined; however, its overall place in the treatment of other forms of cancer awaits delineation in future well-controlled comparative studies.

Placebo-controlled double-blind comparative study on the preventive efficacy of mesna against ifosfamide-induced urinary disorders

In order to evaluate the preventive efficacy, safety and usefulness of mesna (Sodium 2-mercaptoethane sulfonate) against ifosfamide-induced urinary disorders, a placebo-controlled double-blind comparative study was performed. Ifosfamide was administered by intravenous drip infusion at a daily dose of 2 g/m2 for 5 consecutive days, and mesna was intravenously administered at 20% of the ifosfamide dose, three times daily for 5 consecutive days. The results obtained are as follows. (a) Of 101 accrued patients, 91 patients were evaluated consisting of 45 for the mesna group and 46 for the placebo group. There was no intergroup difference in the number of the evaluated cases and patient characteristics. (b) Micturition pain and feeling of residual urine graded as moderate or severe were not observed for the mesna group, but were observed for the placebo group with incidences of 19.6% (9/46) for micturition pain and 15.2% (7/46) for feeling of residual urine; the intergroup differences in the appearance of these urinary symptoms were statistically significant (P = 0.0003 for micturition pain; P = 0.0009 for feeling of residual urine). The incidence of hematuria graded as moderate or severe was 6.7% (3/45) in the mesna group, which was significantly lower than the 32.6% (15/46) in the placebo group (P = 0.0008). (c) No side-effect attributable to mesna was observed. (d) A judgment of "useful" was obtained in 80.0% (36/45) of the patients treated with mesna, which was significantly higher than the 34.8% (16/46) of the patients treated with placebo (P = near 0). On the basis of the above results, we conclude that the preventive efficacy, safety and usefulness of mesna against ifosfamide-induced urinary disorders have been well demonstrated in this study.