Mitomycin C skin toxicity studies in mice: reduced ulceration and altered pharmacokinetics with topical dimethyl sulfoxide

A series of toxicologic and pharmacokinetic studies were performed in BALB/c mice administered intradermal (ID) mitomycin C (MMC) at doses of .015 to 0.25 mg. Dose-dependent skin ulcers were produced at clinically relevant MMC dose levels of .05 and .075 mg (3.6 to 10.7 mg/m2). These doses produced peak ulcers of 0.15 to 0.22 cm2, respectively, one to five days after injection. The integrated ulcer area X time values (area under the curve [AUC] ulceration) were 0.89 and 3.11 cm2 X d. A large number of local pharmacologic adjuvants were found to be ineffective at reducing MMC ulceration after proximal ID injection. These included diphenhydramine, catalase, heparin, hyaluronidase, hydrocortisone, cysteine, N-acetylcysteine, lidocaine, vitamin E, and superoxide dismutase. Also, neither topical heating nor cooling of skin reduced MMC ulcerations. In contrast, a single topical application of a 100% dimethyl sulfoxide (DMSO) solution completely prevented 0.025 mg MMC-induced skin ulceration and significantly reduced .075 mg MMC ulceration (P less than .05 by multiple range tests). Topical DMSO also altered the disposition of ID MMC in mouse skin but not in plasma. Unexpectedly, the DMSO applications slowed MMC elimination from the skin. DMSO significantly increased the AUC for MMC in skin from 0.89 to 2.25 ng/h/mL of tissue (P less than .05). DMSO did not alter the degree of protein binding in skin tissue nor the in vitro chemical stability of MMC in skin tissue homogenates. These results show that experimental MMC-induced skin ulcers in mice can be ameliorated with an immediate application of topical DMSO. This effect is not due to enhanced systemic drug uptake, but may be due to reduced reactivity of MMC with target cellular nucleophiles.

[Intraarterial bolus infusion followed by rapid removal of anticancer agents with hemocarboperfusion under local hyperthermia in advanced hepatic cancer]

Reported herein is a new multidisciplinary treatment modality for unresectable hepatic cancer in which local hyperthermia and intraarterial infusion of bolus anticancer agent are simultaneously undertaken while anticancer agent leaking from the hepatic bed into the general circulation is rapidly removed by charcoal hemoperfusion. Local hyperthermia induced by exposure to 13.56-MHz radiofrequency waves was conducted between one and one and a half hours once or twice a week. During the hyperthermia treatment, a bolus of either 1 mg/kg Mitomycin C or 2 mg/kg Adriamycin was injected into the hepatic artery via a Vascular Access Port, the catheter portion of which had been surgically inserted into the hepatic artery and the reservoir of which had been implanted subcutaneously. In general, a regular dose of 6 mg of Mitomycin C was injected into the Vascular Access Port during the following hyperthermia procedures. In seven of nine patients (78%) treated with this method, a marked reduction in tumor size of more than 50% was observed on computed tomograms. A light to moderate degree of side effects such as leukocytopenia, thrombocytopenia, liver dysfunction or hair loss were noticed after the bolus infusion, but were not so serious as to threaten the patients' lives.

Mitomycin C plasma levels after intravesical instillation with and without hyaluronidase

In 20 patients undergoing transurethral resection for bladder tumor or multiple transurethral biopsies for monitoring after transurethral resection, mitomycin C, 20 mg., was instilled into the bladder immediately after the procedure. Mitomycin C was associated with hyaluronidase, 200.000 U, in 10 patients. Serum levels of mitomycin were determined by column chromatography 30 and 60 minutes after instillation. Hyaluronidase was not found to make any difference in mitomycin absorption. Potential expansions of the therapeutic modalities for preventing recurrent bladder tumor by hyaluronidase are discussed.

A bioassay to measure cytotoxicity of plasma from patients treated with mitomycin C

The unpredictable clinical toxicity observed in patients treated with mitomycin C and the observation that this agent must be reduced to an active form before alkylating target molecules have led to the development of a bioassay which is capable of detecting biologically active forms of mitomycin C in the plasma of drug-treated patients. The bioassay makes use of a repair-deficient mutant of Chinese hamster ovary cells, UV-20, which is 40 to 60 times more sensitive to mitomycin C than its wild-type parent. A standard curve relating in vitro cell colony-forming ability of UV-20 versus drug concentration in the plating medium has been determined. Mitomycin C levels in patient plasma as low as 1 ng/ml can be detected, compared to the 5-ng/ml limit of detection obtained with a high-pressure liquid chromatography assay for the parent compound. This assay has been utilized to detect active drug in plasma obtained from patients with colorectal cancer treated with mitomycin C as a single agent. At the completion of drug injection, serial blood samples were collected in heparinized tubes, and aliquots of plasma were extracted and assayed for mitomycin C levels by high-pressure liquid chromatography, diluted and assayed directly for their toxicity for UV-20 cells, or frozen at -20 degrees C to be assayed at a later time. The activity detected by immediate bioassay was stable up to 2 mo in frozen samples. Plasma pharmacokinetics determined by the bioassay in seven patients were no different than those determined by high-pressure liquid chromatography. No stable, cytotoxic species other than the parent compound were detected by the bioassay in the plasma of patients treated with mitomycin C.

Pharmacology of intraperitoneal infusion 5-fluorouracil and mitomycin-C

The pharmacokinetics of intraperitoneal infusion 5-fluorouracil and bolus administration mitomycin-C have been evaluated and permit one to determine the exposure advantage for this route of administration. as with other forms of regional chemotherapy, the limiting toxicity is locoregional. The therapeutic efficacy of this approach awaits the design and conduct of clinical trials.

[A clinical trial of a new mitomycin C derivative, KW-2083 (7-N-(p-hydroxyphenyl)-mitomycin C)]

KW-2083 [7-n-(p-hydroxyphenyl)-mitomycin C] is a new mitomycin C (MMC) derivative. Its myelotoxicity was compared with that of MMC by using colony-forming unit-spleen (CFU-S) from the femurs of C57BL/6 mice. As a result, it was estimated that the intensity of myelotoxicity of MMC was four times greater than that of KW-2083. Based on this data, a clinical trial of KW-2083 was conducted in 24 cases with various types of advanced solid tumors. KW-2083 was administered by i.v. injection at a dose of 40 mg/body every week. Out of 15 evaluable cases, a case of ovarian cancer showed a partial response. One case of each of ovarian cancer and gastric cancer showed minor response. However, as with mitomycin C, the dose-limiting toxicity of KW-2083 was leukopenia and thrombocytopenia. Other toxicities encountered were nausea, vomiting, anorexia, phlebitis and hepatic dysfunction. There were no cases with renal toxicity. Plasma concentration of KW-2083 was bioassayed in 3 cases who received 40 mg/body as an i.v. bolus injection. Plasma concentration-time curves fitted to a one-compartment model and half-life values averaged 27.6 min. The effective and low toxic dose schedules of KW-2083 should be investigated further.

Systemic blood levels after intra-arterial administration of microencapsulated mitomycin C in cancer patients

Systemic delivery of mitomycin C (MMC) was studied in 6 patients administered microencapsulated MMC (MMC-mc) by an intra-arterial route (IA): 3 IA liver infusions, 3 IA pelvic infusions. Pharmacokinetic data revealed a lower blood MMC availability (peak plasma levels, AUC 0-4 hours) for the pelvis than for the liver; this was attributed to differences in the blood flow infusion rates at these two sites of administration. Direct comparison of systemic MMC exposure was possible for one patient, who received both IA liver MMC (10 mg in standard form, which served as the control) and IA liver MMC-mc (20 mg the day after). The 65% reduction in MMC-mc bioavailability observed for this patient indicates a quantitative local improvement in exposure to the drug and correlates well with the low incidence of systemic side effects noted in preliminary clinical studies.

Detecting mitomycin C in human plasma during intravesical therapy

Mitomycin C (MMC) concentrations in plasma and urine were measured in five patients with intact bladder during intravesical instillation therapy. No MMC was detected in plasma by a selective high performance liquid chromatographic (HPLC) method. The detection limit of the method is 1 ng/ml. Our results are in accordance with clinical experiences of the lack of systemic toxicity during MMC instillation therapy. There was a remarkable loss of MMC in the voided urine. The probable explanation could be that a considerable amount of MMC is absorbed into the bladder wall.

Effects of intra-arterially infused biodegradable microspheres containing mitomycin C

We prepared biodegradable microspheres containing about 5% mitomycin C (MMC) and of 45 +/- 8 microns in diameter. These preparations were infused into the rat hepatic artery as a preclinical model of intra-arterial infusion treatment for patients with inoperable hepatic tumor. The leaked MMC levels in the hepatic vein decreased below the assay limitation 2 hours after conventional MMC injection, whereas in the case of MMC microsphere the leaked drug levels were maintained at almost the same concentration for over 2 hours after infusion. The entrapped period of MMC microspheres within the hepatic artery was at least 2 weeks, and the necrobiotic foci due to antitumor effects of the condensed MMC released from the microspheres were observed in the area fed by these entrapped arterioles. This phenomenon was never observed in the case of conventional MMC and placebo microspheres. Intra-arterial infusion of MMC microspheres may be a promising clinical treatment for patients with malignant hepatic tumor.

Development and application of a sensitive enzyme immunoassay for 7-N-(p-hydroxyphenyl)mitomycin C

An antibody specific for 7-N-(p-hydroxyphenyl)mitomycin C (M-83) was developed and used in a simple and sensitive enzyme immunoassay for detection of this anticancer drug in serum. The imino group of M-83 was covalently coupled to mercaptosuccinyl groups introduced into bovine serum albumin with a cross-linker, N-maleoylaminobutyric acid. The resulting conjugate was then used for the production of a specific antibody to M-83 in rabbits. Enzyme labeling of M-83 was performed using beta-D-galactosidase (EC 3.2.1.23) via m-maleoylbenzoic acid. Antibody production was of sufficiently high titer in rabbits to allow the development of a highly sensitive enzyme immunoassay for the free drug which accurately measures 15 pg of M-83 per assay tube. This assay was monospecific to M-83 and showed almost no cross-reactivity with a variety of other mitomycin analogues (mitomycin A, B, and C; porfiromycin; and acetylmitomycin C). Using this assay, preliminary pharmacokinetic study was undertaken using serial serum samples obtained from a patient who received the drug i.v., revealing a biphasic fashion of the kinetics, with an alpha-serum half-life of 9.7 min and a beta-serum half life of 80 min. An i.v. injection of M-83 into rats and assay of serum concentration revealed a similar biphasic response with an alpha-serum half-life of 8.3 min and a beta-serum half-life of 62 min.

Pharmacokinetics of mitomycin C in dogs: application of a high-performance liquid chromatographic assay

A normal-phase high-performance liquid chromatographic (HPLC) assay was developed for the determination of mitomycin C in plasma and urine. The method involves extraction of mitomycin C from plasma or urine into ethyl acetate-2-propanol-chloroform (70:15:15) with UV detection at 365 nm. Quantitation was performed with an internal standard (porfiromycin) by the peak height ratio method. Excellent correlation was obtained between the HPLC assay and the established microbiological cup-plate bioassay. The pharmacokinetics of mitomycin C were investigated in beagle dogs following a 1-mg/kg iv (22-mg/m2) bolus dose. The plasma mitomycin C concentration versus time data were analyzed by using an open three-compartment model. The average volume of distribution was 1.90 L or 17% of body weight for the central compartment and 7.7 L or 68% of body weight for the terminal elimination phase. The volumes of distribution at steady state, calculated by model-dependent and -independent methods, compared very well with each other and were 6.5 L or 58% of body weight. Total body clearance averaged 112 mL/min, and the mean terminal plasma half-life was 53 min. The 0-24-h urinary excretion of intact mitomycin C accounted for 19% of the dose. The terminal half-life and percent urinary recovery of mitomycin C in dogs is similar to that in humans. Based on these observations, the dog appears to be a good model for studying the disposition of mitomycin C.

Disposition and pharmacokinetics of a polymeric prodrug of mitomycin C, mitomycin C-dextran conjugate, in the rat

The disposition and pharmacokinetics of a polymeric prodrug of mitomycin C (MMC), mitomycin C-dextran conjugate (MMCD), following iv bolus administration was studied in rats. Three types of MMCD, conjugates with dextran of molecular weights of 10,000, 70,000, and 500,000, were tested and disposition of carrier dextran and MMC was determined by 14C radioactivity counting and bioassay, respectively. Radioactivity was accumulated in the reticuloendothelial system such as the liver, spleen, and lymph nodes after injection of all three types of 14C-MMCD, but not in the lung, heart, and muscle. Renal distribution of 14C-MMCD varied with the molecular size of the carrier. After injection of cold MMCD, plasma concentrations of MMC in the free and conjugated forms were determined separately on the bases of bioassay. Similar sustained plasma levels of MMC were detected regardless of the carrier size although the concentration-time profiles of MMCD varied with the size of dextran. These plasma concentration data were fitted to a compartment model including a first order conversion process from MMCD to MMC in the central and peripheral compartments of MMCD. Kinetical analysis revealed that MMCD acts as a reservoir of MMC which behaves characteristically as a macromolecule while supplying active MMC in the body.

Pharmacokinetics of mitomycin C in non-oat cell carcinoma of the lung

The disposition kinetics of the cancer chemotherapeutic agent mitomycin C have been studied in six male patients receiving mitomycin C in combination with cisplatin and vinblastine for non-oat cell carcinoma of the lung. Following rapid IV administration of mitomycin C (10 mg/m2), serum concentration-time course data were biexponential, with biologic half-lives of 46.2 +/- 12.1 min (mean +/- SD). Pharmacokinetic analysis of data by the CSTRIP and NONLIN digital computer programs generated parameters which suggested extensive distribution (V area = 656.8 +/- 169.8 ml X kg-1, mean +/- SD) and, as reported for other alkylating agents, rapid elimination (total body clearance = 10.3 +/- 3.2 ml X kg-1 X min-1, mean +/- SD). Interpatient variations in pharmacokinetic parameters were relatively small, suggesting that close monitoring of mitomycin C therapy might be unnecessary in patients with normal renal and hepatic function.

Effects of total body irradiation followed by bone marrow transplantation on the disposition kinetics of mitomycin-C in the rat

The effects of total body irradiation followed by bone marrow transplantation on the disposition kinetics of intravenously-administered mitomycin-C have been studied in the Wistar-Furth rat. Five test animals received total body irradiation (1000 rads) followed by intravenous administration of 3 X 10(8) bone marrow cells per kg body weight. Five control animals were sham-irradiated and received an equal volume of blank suspension medium. One day after these treatments, each rat received mitomycin-C (10 mg/kg) by rapid intravenous injection and serial blood samples were obtained. Serum mitomycin-C concentrations were measured by high performance liquid chromatography and pharmcokinetic parameters were calculated after NONLIN analysis of data. Smaller total body clearances in test animals were probably due to radiation-induced inhibition of microsomal enzyme activity. Reduced volumes of distribution were observed in test animals although the reason for this is unclear. Future studies should assess the clinical significance of these results.

The stability and antitumor activity of recycled (intravesical) mitomycin C

Although intravesical mitomycin C (MMC) is effective in the treatment of superficial bladder cancer, its expense is a major factor limiting its use. These authors have analyzed the antitumor activity and stability of MMC following 2-hour intravesical instillation in consideration of recycling the drug or using a smaller dose over a longer retention time. The first voided urine samples from 11 patients who received 40 mg MMC intravesically were measured for MMC content by high performance liquid chromatography (HPLC). An average of 50% of the parent drug was recovered. MMC from the urine samples inhibited the growth of a transplantable murine transitional cell carcinoma as effectively as stock drug. Moreover, MMC is relatively stable in human urine at body temperature. These findings suggest that recovery and reuse of the intravesically administered drug is possible and if sterility and appropriate concentrations can be established for the initial and subsequent doses, the drug may be able to be recycled.

[Pharmacokinetics of mitomycin C in cancer patients during prolonged administration of the preparation]

The mitomycin C levels in the blood of patients subjected to prolonged intravenous injection of the drug in 200-300 ml of isotonic sodium chloride solution for 15-50 minutes were determined in the microbiological test system consisting of E. coli and 1.5 per cent of agar in the meat-peptone broth with restricted contents of the nutrients. Such administration of the drug usually provided lower blood levels than intravenous injections of the drug in analogous doses. However, the drug renal excretion was also less intensive. It suggested that the drug administered for a prolonged period was more completely absorbed by the host tissues. This was confirmed by much lower blood levels of the drug, when the tumors were large, as compared to those in patients with insignificant residues of the tumor tissue after surgical resections. The curves of mitomycin C distribution in the blood indicate that the pharmacokinetics of the drug in patients with tumors is a multi-factorial function.

Absorption of doxorubicin-hydrochloride and mitomycin-C after instillation into noninfected and infected bladders of dogs

The described investigations were carried out in order to determine the degree of absorption of doxorubicin, and mitomycin-C after intravesical instillation into noninfected or Staphylococcus aureus-infected bladders in beagle dogs. The drug concentrations in the bladder wall were determined using diffusion chambers with permeable membranes. Two hours after end of instillation of 10 mg. doxorubicin, a concentration of 1.4 ng. per ml. was measured in the bladder wall of noninfected animals, and 3.75 ng. per ml. in that of infected animals (p less than 0.05). The simultaneously measured serum concentration reached mean peak levels after 30 minutes. The concentrations in infected animals were 3 times higher (1.9 ng. per ml.) than in noninfected animals (0.6 ng. per ml.) (p less than 0.05). After instillation of 1 mg. per kg. bw. mitomycin-C the concentration in both groups of animals was below 0.06 micrograms per ml. Doxorubicin concentrations were determined with a radioimmunoassay and mitomycin-C with a micro-agar diffusion method.

Reversed-phase high-performance liquid chromatographic determination of mitomycin C in human serum

A reversed-phase high-performance liquid chromatographic method is presented by which the cancer chemotherapeutic agent, mitomycin C, may be measured in human serum. A mobile phase of methanol:water (35:65) passed through a mu-Bondapak C-18 column at a rate of 1.0 ml/min produced a sharp, symmetrical band for mitomycin C. An improved serum extraction procedure, using a reversed-phase sample preparation cartridge, proved to be efficient and reproducible. Recovery over a concentration range of 10-100 ng/ml was 81.6% with a between-day coefficient of variation of 4.6% (n = 5). The within-day coefficient of variation at 50 ng/ml was 5.6% (n = 10). Ultraviolet detection at a wavelength of 365 nm was sensitive to serum concentrations of 10 ng/ml. Serum concentration-time course data from lung cancer patients receiving mitomycin C by rapid intravenous injection are presented.

[Serum levels of mitomycin C following a high-dose continuous hyperthermic peritoneal perfusion]

Valid therapeutic means have not been established for treatment of disseminated peritoneal metastasis of carcinoma. Continuous hyperthermic peritoneal perfusion (CHPP) with high-dose of mitomycin-C (MMC) was applied to 26 patients with peritoneal metastasis from gastric, rectal or ovarian cancers. Levels of MMC in the sera and in the perfusate were measured. The results obtained were: 1. Approximately a half of the dose of MMC added into the perfusion fluid was recovered. 2. When perfused with 100 mg of MMC, the maximum serum concentration of MMC was equivalent to 1/3 of the maximum serum level when injected with 10 mg of MMC intravenously. Therefore, MMC which could not be detected in CHPP seemed to be retained in the abdominal cavity. 3. Bone marrow inhibition caused by CHPP was observed in only 2 of 26 patients. 4. The total dose of 300 mg of MMC, consisting of the maximum dose of 100 mg each, is acceptable in CHPP without any severe side effect. 5. CHPP exerts antitumor effects when utilizing hyperthermia and a high-dose of MMC on the disseminated peritoneal foci of carcinoma.