Amsacrine cardiotoxicity: assessment of ventricular function by radionuclide angiography

Serial assessment of ventricular function by means of a nuclear medicine technique was performed in six patients with malignant disease receiving chemotherapy with amsacrine. Two patients who received treatment long enough so that greater than 580 mg/m2 of the drug was administered showed a significant decrease in left ventricular ejection fraction. Four patients who received total doses of 325-510 mg/m2 of amsacrine did not experience significant change in their cardiac function.

Phase II study of amsacrine gluconate in refractory leukemia

Twenty-six adults with refractory leukemia were treated with amsacrine gluconate, a new formulation. There were two complete and two partial remissions. This preparation has no apparent advantage when compared with amsacrine lactate.

A non-clonogenic assay for the determination of the sensitivity of leukemic cells to chemotherapeutic agents

A new method for measuring the effects of chemotherapeutic agents on leukemic cells has been developed. In this method tritiated thymidine [( 3H]-TdR) is used to determine the surviving proportion of leukemic cells which are stimulated to proliferate by colony-stimulating factor (CSF). The effects of four antileukemia drugs on bone marrow cells from 20 AML patients were studied using this method and the results correlated well with the effects of the drugs on the CFUc, which were studied simultaneously. Using the liquid culture method drug effects were measured on five bone marrow specimens which failed to clone in the CFUc assay as well as on three specimens which produced too few colonies/clusters to allow estimation of drug effects.

Failure of the intercalating agent 4'-(9-acridylamino)-methanesulphon-m -anisidide to induce DNA-repair replication in cultured human cells

A search has been made for DNA-repair replication in cultured human cells treated with the DNA-intercalating agent 4'-(9-acridinylamino) methanesulphon--m-anisidide (m-AMSA). Previous reports had suggested that the transient appearance of protein-associated DNA-strand breaks in mammalian cells treated with m-AMSA might be indicative of a rapid DNA-repair process. The present experiments suggest that such a repair process is unlikely to occur as, even in cells treated with high concentrations of m-AMSA (50 microM) for 20 h, DNA repair replication could not be detected down to the limits of sensitivity (1 million nucleotides replaced per cell).

Divergent activity of derivatives of amsacrine (m-AMSA) towards Lewis lung carcinoma and P388 leukaemia in mice

A series of acridine monosubstituted derivatives of the antitumour agent amsacrine [4'-(9-acridinylamino)methanesulphon-m-anisidide] has been tested for activity against intraperitoneally inoculated P388 leukaemia and intravenously inoculated Lewis lung carcinoma growing in DBA/2J X C57BL/6J mice, and treated using a q4d X 3 intraperitoneal injection schedule. Whereas all derivatives tested exhibited moderate to high activity towards the leukaemia, activity against the lung tumour varied from inactive to curative. Amsacrine itself displayed low but statistically significant activity. Cyclophosphamide and 2-beta-D-ribofuranosylthiazole-4-carboxamide (tiazofurin) were highly active. 5-Fluorouracil was active but doxorubicin, daunorubicin, ametantrone and mitoxantrone showed no significant activity. Since the Lewis lung carcinoma is responsive to a high proportion of agents active against solid tumours in the clinic, it is concluded that some derivatives of amsacrine could be considerably more active than amsacrine itself against human solid tumours.

Effect of temperature on the cytotoxicity of vindesine, amsacrine, and mitoxantrone

The effect of elevated temperature on the cytotoxicity of three new anticancer drugs (vindesine, mitoxantrone, and amsacrine [AMSA]) was tested in Chinese hamster ovary cells in vitro. Three distinct patterns of interaction with hyperthermia were observed. Vindesine, tested at 37 degrees C, produced a 50% cell kill when concentrations of greater than or equal to 1.0 micrograms/ml (up to 3.0 micrograms/ml) for 1 hour were used. At 42.4 degrees C, concentrations greater than 1.0 micrograms/ml for 1 hour caused a 60% cell kill (an additive cytotoxic effect). Mitoxantrone produced concentration-dependent lethality at 37 degrees C (89% cell kill after 0.25 micrograms/ml for 1 hour; 99% cell kill after 1.0 micrograms/ml for 1 hour). Exposure to mitoxantrone at 42.4 degrees C resulted in synergistic cytotoxicity (97% cell kill after 0.25 micrograms/ml for 1 hour; 99.98% cell kill after 1.0 micrograms/ml for 1 hour). In contrast, treatment with AMSA at 42.4 degrees C inhibited cytotoxicity (99.98% cell kill after 5 micrograms/ml for 1 hour at 37 degrees C; 91% cell kill after 5 micrograms/ml for 1 hour at 42.4 degrees C). AMSA was not inactivated after being heated at 42.4 degrees C for 1 hour prior to treatment of cells at 37 degrees C.

Amsacrine in refractory adult acute leukemia: a pilot study of the Southeastern Cancer Study Group

A phase II pilot study of amsacrine in refractory adult acute leukemia was conducted by the Southeastern Cancer Study Group from May 1979 to August 1980. Amsacrine, 90 mg/m2, was given daily for 5-8 days to 45 patients with acute myeloblastic leukemia, 15 patients with acute lymphoblastic leukemia, and six patients with blastic transformation of chronic granulocytic leukemia. Of the 66 patients entered in the study, 59 (89%) were evaluable for response. Complete remissions were observed in eight of 41 evaluable patients with acute myeloblastic leukemia (20%) and in three of 12 with acute lymphoblastic leukemia (25%). Remissions were short-lived (median, 7.9 weeks; range, 2-27). Toxic effects included the expected myelosuppression (100%), as well as moderate to severe stomatitis (46%), hyperbilirubinemia (30%), and supraventricular tachycardia (1.5%). This cooperative group pilot study confirms previous reports from single institutions that amsacrine is a useful drug in the treatment of refractory adult acute leukemia and is worthy of further study.

Potential antitumor agents. 39. Anilino ring geometry of amsacrine and derivatives: relationship to DNA binding and antitumor activity

The clinical antileukemic drug amsacrine and analogues are thought to exert their biological activity by binding tightly but reversibly to DNA, with the acridine chromophore intercalated and the anilino group making additional binding contact in the minor groove of the double helix. In this binding model the steric environment around the 3'- and 5'-positions of the anilino ring is crucial. Two 3',5'-disubstituted analogues of amsacrine have been prepared, and their conformation, DNA binding properties, and antitumor activity were determined and compared with corresponding unsubstituted and 3'-substituted compounds. Addition of 3'- and 3',5'-substituents have little effect on minimum-energy conformations of the anilino side chain but have significant effects on DNA binding and biological activity. Monosubstitution lowers binding constants several-fold, but intercalative binding with extensive drug-base pair overlap is retained. Disubstitution lowers binding further, and although the binding is still intercalative as assessed by unwinding angles, it appears to occur with little drug-base pair overlap, as determined by high-field NMR studies of DNA imino proton shifts. These changes in DNA binding are accompanied by an abrupt change in biological activity, with the 3',5'-disubstituted analogues proving inactive and nontoxic even though other physicochemical properties, such as lipophilicity and stability, remain within acceptable limits. This study provides further evidence that the binding of drugs to DNA has a critical influence on their biological activity.

Potential antitumor agents. 38. 3-substituted 5-carboxamido derivatives of amsacrine

The synthesis and biological evaluation of a series of 3-substituted 5-carboxamido derivatives of amsacrine (m-AMSA) are described. This series was developed as the result of previous quantitative structure-activity relationship (QSAR) studies of the antitumor activity of 9-anilinoacridine derivatives. In agreement with these studies, this class of compounds, possessing a variety of small nonpolar groups at the 3-position, together with very hydrophilic carboxamido groups at the 5-position, have high in vivo activity against animal leukemia models.

An extremely potent anilinoacridine inhibitor of aldehyde oxidase

An acridine antitumor agent, 4'-(9-acridinylamino)methanesulfon-m-anisidide, has been found to be an extremely potent competitive inhibitor of aldehyde oxidase (EC 1.2.3.1). The inhibitor constant (Ki) was determined to be 0.06 microM. The degree of enzyme inhibition was quite sensitive to small changes in the structure of the inhibitor's anisidide moiety. Drug inhibition was specific for aldehyde oxidase and inhibition was not detected with the other mammalian molybdenum iron-sulfur flavoenzyme, xanthine oxidase (EC 1.2.3.2). Members of the 4'-(9-acridinylamine)methanesulfonanilide series might be useful probes in the study of the structure and function of aldehyde oxidase.

Reconstitution of intercalator-induced DNA scission by an active component from nuclear extracts

Treatment with intercalating agents causes formation of protein-associated DNA breaks in mammalian cells in culture and in the nuclei isolated from these cells. We found that this effect, when induced by the intercalator m-AMSA, required a component which could be dissociated from nuclei by 0.3 M NaCl. The effect was restored by combining the extracted nuclei with the nuclear extract. The active component of the extract eluted in gel filtration at a point corresponding to a molecular weight of 800 000. During its reaction with DNA, DNA-protein links and DNA breaks appeared in approximately equal frequencies. In this respect the reaction stimulated by m-AMSA resembled the reaction of a topoisomerase with DNA. However, intercalator-stimulated formation of protein-associated DNA breaks differed from the activity of the nuclear topoisomerase I in that there was a different optimum salt concentration and a different apparent molecular weight.

A phase II study of m-AMSA in patients with malignant mesothelioma

Nineteen patients with histologically confirmed malignant mesothelioma were treated with m-AMSA at the University of Pretoria. All patients had evaluable disease and an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0-3. m-AMSA 120 mg/m2 was given IV every 3 weeks. Hematopoietic suppression was the major side-effect. Eleven patients developed leukopenia. There was one partial response (16 weeks), and a no change status was documented in 12 patients (median duration of 20 weeks). The median survival time of patients was 27 weeks from entry on study. Radionuclide ventricular ejection fraction tests were performed to evaluate cardiac function.

Comparative cardiac oxygen radical metabolism by anthracycline antibiotics, mitoxantrone, bisantrene, 4'-(9-acridinylamino)-methanesulfon-m-anisidide, and neocarzinostatin

This study examined the effects of various anthracycline antibiotics and mitoxantrone, bisantrene, 4'-(9-acridinylamino)-methanesulfon-m-anisidide (m-AMSA), and neocarzinostatin on oxygen radical formation by cardiac sarcoplasmic reticulum and submitochondrial particles. Doxorubicin, daunorubicin, rubidazone, and aclacinomycin A stimulated superoxide production by both heart fractions in a dose-dependent fashion that appeared to follow saturation kinetics. The anthracycline drugs also significantly increased hydrogen peroxide production by heart sarcosomes and submitochondrial particles. On the other hand, mitoxantrone, bisantrene, m-AMSA, and neocarzinostatin did not significantly enhance cardiac reactive oxygen metabolism. Thus, it is unlikely that the mechanism of the cardiac toxicity produced by mitoxantrone and m-AMSA in patients previously treated with anthracycline drugs can be directly related to oxidation-reduction cycling catalyzed by cardiac flavin dehydrogenases.

Phase II study of PALA and AMSA in advanced renal cell carcinoma

Ninety-two evaluable patients with measurable renal cell carcinoma participated in a phase II trial of PALA (1500 mg/m2/day for 5 days every 3 weeks) versus AMSA (120 mg/m2 every 4 weeks). No complete responses occurred; objective partial response rates were 5% for PALA and 3% for AMSA. Treatment did not influence survival, but ambulatory patients survived longer than did nonambulatory patients. Mucocutaneous and acute gastrointestinal toxicity occurred with PALA, while hematologic toxicity predominated in AMSA treatments. At these schedules neither drug has significant single-agent activity in renal cell carcinoma.

High-performance liquid-chromatographic method for the determination of 4'-(9-acridinylamino)methanesulfon-m-anisidide in plasma

A rapid and selective high-performance liquid chromatographic method for the measurement of 4'-(9-acridinylamino)methanesulfon-m-anisidide (AMSA), a new anticancer drug, has been developed. The method employed an analogue of AMSA, 4'-(3-methyl-9-acridinylamino)methanesulphonanilide as internal standard. Plasma samples were acidified, washed with hexane, readjusted to pH 9.0 and extracted with diethyl ether. The evaporated extract was chromatographed on a Radial-Pak C18 column using acetonitrile--water containing 0.01 mol/l triethylamine phosphate as mobile phase. Detection was by UV absorbance at 254 nm. Chromatography time for each sample was 5.5 min. Using 0.5 ml of plasma, AMSA concentrations as low as 50 nmol/l could be measured with acceptable accuracy and precision. Patients samples remained stable when stored at -20 degrees C for up to one month. Plasma AMSA concentrations were followed for 24 h after 200 mg/m2 infusions in two patients with acute myeloid leukemia. This method appears eminently suitable for investigation of the pharmacokinetics of AMSA in patients and laboratory animals.

Evidence that mAMSA induces topoisomerase action

Evidence is presented that the topoisomerase inhibitors novobiocin and coumermycin inhibit the production of double-strand breaks in mouse mastocytoma cell nuclear DNA by the anticancer drug 4'[(9-acridinyl)amino]-methanesulphon-m-anisidide (mAMSA). Novobiocin did not inhibit resealing of DNA breaks induced by mAMSA. It is suggested that mAMSA intercalation into DNA induces the action of a type II topoisomerase. mAMSA and oAMSA were equally effective in breaking the DNA in isolated nuclei.

Phase II evaluation of m-AMSA (4'-(9-acridinylamino)-methanesulfon-m-anisidide) in patients with adenocarcinoma of the pancreas

m-AMSA (4'-(9-acridinylamino)-methanesulfon-m-anisidide, a substituted acridine derivative, was administered to 27 patients with adenocarcinoma of the pancreas. The dose ranged from 90-210 mg/m2/course. The toxic effects were primarily hematologic. Twenty-four of the patients were evaluable for response. These patients received a median of 2 doses (range 1-7). The median time from diagnosis to therapy was 2 months (range 0-16). Two patients achieved an MR lasting 4 and 2 months, respectively. Two patients had stabilization for 6 and 3 months. The median survival for all patients was 3 months. Survival distribution for patients with prior chemotherapy versus no previous therapy was not significantly different (p = 0.5). This study suggests that m-AMSA has little value as a single agent in the treatment of adenocarcinoma of the pancreas.

Ventricular fibrillation following AMSA. Uncomplicated retreatment following correction of hypokalemia

A patient is presented who developed ventricular fibrillation following AMSA treatment, in the setting of hypokalemia. Resuscitation was successful, chemotherapy treatment response was observed, and further treatment with AMSA was uncomplicated after correction of the hypokalemia. With careful attention to electrolyte balance, a prior history of AMSA-induced cardiac arrhythmia does not contraindicate further treatment with AMSA.

4'-(9-acridinylamino)methane-sulfon-m-anisidide (m-AMSA) and 5-azacytidine (AZA) in the treatment of relapsed adult acute leukemia

Between March 1980 and December 1981, 22 patients were treated with 4'(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA) and 5-azacytidine (AZA), each given by I.V. push in a dosage of 150 mg/m2 for 5 days. Seven of 12 prior-remitting, acute nonlymphoblastic leukemia (ANLL) patients achieved complete remission (58%). Six ANLL patients who failed to remit on standard daunorubicin-cytosine arabinoside programs also failed to remit on the m-AMSA-AZA combination. Two patients with relapsed acute lymphatic leukemia (ALL) also failed while two patients with chronic myelocytic leukemia (CML) in evolution were cytoreduced. The seven patients who achieved remission had additional relapse-free survival for a median of six months (range 1-23+ months). One patient obtained a second remission with m-AMSA-AZA after relapse which followed a 9-month period of nonmaintained remission. Most patients demonstrated mild to moderate nausea and vomiting. Hepatic toxicity was mild to infrequent. Only four patients showed cardiac toxicity which was not life-threatening. The most troublesome toxicity was mucositis and was seen in 11 patients; four whom required I.V. hyperalimentation. We conclude that this combination is an effective salvage program for relapsed prior-remitting ANLL. Future studies should be conducted in three areas. The first study might be a comparison of relapsed prior-remitting ANLL with single-agent m-AMSA. The second, in untreated ANLL, following induction with DAT, might use m-AMSA-AZA in consolidation and maintenance arms of future protocols. The final study should explore m-AMSA-AZA activity in evolved CML in a greater number of patients.

Influence of scheduling on therapeutic and toxic effect of AMSA in Lewis lung carcinoma

The antitumor activity and toxic effect of AMSA were studied in Lewis lung carcinoma (3LL) at various stages of growth. The total dose of drug injected IP was 15 mg/kg, which is equivalent to the LD10. Different administration schedules were tested, these being single-injection schedules (day 1, 7, or 10 after tumor implantation) and repeated low-dose-injection regimens (days 1, 4, and 7 and days 1-7 after tumor implantation). Tumor weight inhibition, retardation of growth, reduction in the number of metastases, and median survival time of treated mice over controls were analyzed as end-points to evaluate the antitumor activity of AMSA. Early deaths and changes in white blood cell count were considered as parameters of toxicity. Our findings can be summarized as follows: (1) AMSA is only minimally effective against primary 3LL tumor at all the growth stages examined and no schedule-dependency is detected; (2) a greater reduction in metastases (70%-77%) is found when the drug is administered fractionally than when it is given in a single dose (39%-60%); (3) irreversible leukopenia is induced by the single-dose schedule of AMSA administration while after repeated low doses the white blood cell counts are in the same range of those of the control groups. Therefore, because of the schedule-dependency of toxicity and reduction in metastases, fractionated administration of AMSA at this dose level would be suitable for adjuvant chemotherapy.

[Phase II study of AMSA in adults with acute therapy-refractory leukemias]

The acridine derivative AMSA, Amsacrine, is a new anticancer drug which was effective in patients with advanced AML and ALL in studies performed in USA. In a multicenter phase II trial we treated 27 patients with acute resistant leukemia with AMSA. All presented progressive disease following several drug combination regimens. Out of the 25 evaluable patients 5 were resistant to primary therapies, 13 were in 2nd relapse, 6 in 3rd, and 1 in 4th relapse. Dosage was 75 mg/m2, iv, day 1-7, all 3-5 weeks. On an average, only 76% of the planned dose per cycle could be given, due to severe leucopenia. From 21 patients with ALL, 1 CR and 3 PR were observed; the 3 patients with ALL presented 1 CR and 1 PR. 1 AUL showed progressive disease. In all patients a marked cell reduction could be observed in the peripheral blood. The general tolerance was good. The most important side-effect was bone-marrow toxicity, 48% (12/25) presented leucopenia less than or equal to 600/mm3, 5 (20%) had fatal septic complications. All 5 early death presented high initial leucocyte counts of greater than or equal to 32.000 mm3 as a common risk factor. In conclusion, AMSA is an effective drug in heavily pretreated patients with AML and ALL.