[Dose intensity and clinical response in patients with advanced gastric carcinoma treated by induced hypertension chemotherapy]

Dose Intensity (DI) was analyzed among 52 eligible and complete patients with advanced gastric carcinoma receiving ADM, 5-FU & MMC (AFM) combination regimen under angiotensin II Induced Hypertension Chemotherapy (IHC). In the induction period DI of CR either in the initial response time or in the effective tumor reduction time was smaller than that of PR, although DI of total period of AFM administration was not different. Based on the evidences, heterogeneous distribution in tumor blood flow under normotension got improved under hypertension by angiotensin II, and chemotherapeutic effects were enhanced. A possibility of the reduction of doses of the drugs administered was suggested. In the maintenance, based on the clinical results, it is mentioned that DI is also useful for an indicator to decide the doses and continuation periods of drugs to be administered. Further investigation on DI will lead to obtain much better maneuver of chemotherapy.

Evaluation of mizoribine as an immunosuppressant in subrenal capsule assay using immunocompetent mice

We studied the application of mizoribine (MZR) to normal immunocompetent mice in subrenal capsule assay (SRCA) by means of tumor growth curve determination, histological analysis and autoradiography. At 400 mg/kg, MZR prolonged the actual tumor growth and moderately reduced the host reaction. Doses below 200 mg/kg did not effectively suppress the host reaction. The maximal weight loss of mice in the 400 mg/kg group reached 29%, but did not exceed 10% within 8 days. Hence, we applied 400 mg/kg of MZR to SRCA for up to eight days for cancer chemotherapy testing. This dose of MZR did not affect the labeling index of tumor cells compared with the control.

[Phase I clinical study of CPT-11. Research group of CPT-11]

CPT-11 is a new derivative of Camptothecin. Phase I clinical study of single administration with CPT-11 was carried out by a cooperative study group. Starting from 50 mg/m2 (n), dose was escalated to 350 mg/m2 (7n). Dose limiting factor was found to be a decrease in WBC counts (especially in neutrophils), and MTD was presumed to be 250 mg/m2 or more. Nadir of WBC counts was observed after about a week, and it took 2-3 weeks for recovery. The decrease in platelet number and hemoglobin content was mild. Other side effects included G-I toxicities, alopecia, etc. However, no toxic effects on the heart, kidney, lung were observed. SN-38, main metabolite of CPT-11, was observed in blood, and excreted rapidly. Anticancer effects were suggested with dose of 165 mg/m2 or more against colon cancer, gastric sarcoma, melanoma and lung cancer. It is suggested that the optimal dose schedule for an early Phase II study is 200 mg/m2 every 3-4 weeks. However, not only leukopenia but also marked G-I toxicities being noted in some cases, care should be taken for those side effects.

[Therapeutic evaluation of combination therapy using C-425, human native immunoglobulin liquid preparation for i.v. administration, with antibiotics in severe infections in the field of internal medicine]

A novel human native immunoglobulin liquid preparation for intravenous injection, C-425, was used in combination with antibiotics to study its efficacy, safety, and usefulness in 262 patients with severe infections which had not responded to antibiotic therapy of 3-day or more duration. As a result of the Committee judgement, 12 of the 262 patients were excluded from this study; 87 were included only in safety analysis; 163 (62.2%) were included in efficacy, safety, and usefulness analyses (complete inclusion). The complete analysis of 163 patients consisted of 93 patients (57.1%) with suspected septicemia, 33 (20.2%) with pneumonia, and 18 (11.0%) with septicemia. Eighty percent or more of the patients had severe underlying diseases such as leukemia and malignant lymphoma. Clinical efficacy of C-425 was judged by the doctors in charge to be "excellent" or "good" in 49.1% of the total cases. The rate of effectiveness was calculated at 74.8% when "excellent", "good" and "fair" cases were all included. Similarly, the rate of effectiveness calculated from the results of Committee judgment was 53.4% when "excellent" and "good" cases were included, and 68.7% when "excellent", "good" and "fair" cases were included. Microbiological assessment was conducted in 19 patients. Causative organisms were eliminated in 11 patients, decreased in number in 1, persisted in 5, and replaced in 2. The rate of elimination was 57.9%. Side effects appeared in 6 of 250 patients (2.4%). It was judged that 3 patients (1.2%) of the 6 were affected by the drug or suspected to be affected, but they were not considered clinically important. Hepatic disfunction was found in 4 patients (1.6%) of the 250; but it was not clarified whether this was related to the drug. From these results, C-425 was considered to be an effective and very safe drug for treating severe internal infections.

[In vivo antitumor activity of mitoxantrone and the flow cytometric analysis of its influence on cell cycle transition--comparison with doxorubicin and aclarubicin on ascitic hepatoma AH109A cells]

Mitoxantrone was compared with doxorubicin and aclarubicin of its in vivo antitumor activity and influence on cell cycle transition by use of rat ascitic hepatoma AH109A. Antitumor activity determined by the cell growth curve was similar in mitoxantrone and doxorubicin, but the sensitivity of AH109A to aclarubicin was lower than that to the other two drugs. Doxorubicin and mitoxantrone showed all phase arrests with 1/10 of maximally tolerated dose (MTD), and with lower concentrations a strong arrest at G2 phase was observed, thus, mitoxantrone appeared to have a similar antitumor activity on AH109A to that of doxorubicin. Aclarubicin, with 1/10 MTD, demonstrated only a transient arrest at G2 phase, cells arrested at G2 phase entering into the next phase. With below 1/10 MTD, there was no appearance on histograms, and the influence on AH109A cell cycle transition by aclarubicin was considered to be little in comparison with doxorubicin and mitoxantrone.

Damage to DNA strand and the effects of anticancer drugs

Cancer chemotherapy is, in a sense, similar to the treatment of infectious disease with antibiotics. The main mechanism of action is on DNA and its precursor, and in the process that anticancer drugs exert the effect on cancer cells, the cells always have abnormal metabolism or destruction of DNA. The main cellular target of most alkylating agents, or anticancer antibiotics is DNA, however, among the anticancer drug newly synthesized, there are some compounds which exert the action on DNA. Quinocarmycin, KT6149, which is a derivative of MMC, YM534, which possesses a platelet agglutinating activity, and MCNU, a nitrosourea compound were studied on the anticancer activity and on damage to DNA strand, and it was found that the lethal effect was deeply concerned with single strand scission of DNA.

[An experimental study on subrenal capsule assay (SRCA)--problems for the use of immunosuppressive agents]

We studied whether or not cyclosporin A (CSA) has a usefulness in subrenal capsule assay (SRCA) with normal immunocompetent mice. Sixty mg/kg of CSA was given to BDF1 mice daily subcutaneously, and various dosages of adriamycin (ADR) was given intravenously on day 2. The body weight of BDF1 mice decreased over 20% within ten days when ADR was given at more than 5 mg/kg. MX-1, a human breast carcinoma line is known to be sensitive to ADR. This tumor was implanted subcutaneously in the back of BALB/c nu/nu mice and chemosensitivity was tested against ADR. ADR resulted to be positive at the dose of 8 mg/kg. On the contrary, the dose of 5 mg/kg proved to be negative, and hence the result of SRCA would be false negative, if the dose of ADR is reduced to avoid the toxicity of CSA. The tumor grew slowly when only 60 mg/kg of CSA was given daily for three weeks, and the inhibition rate was 56.2%. The toxicity of CSA was neglected because of the body weight loss was approximately 13%. CSA may have the antitumor effect by itself, and we therefore suggest that the CSA is not useful for SRCA.

[Randomized multicenter trial of sequential methotrexate and 5-fluorouracil versus 5-fluorouracil alone in advanced gastric cancer]

In a recent phase II trial we have shown a favorable response rate for sequential methotrexate-5-fluorouracil (MF) in advanced gastric and colorectal cancer. We determined the therapeutic effect of sequential MF in patients with advanced gastric cancer by comparing it to 5-fluorouracil alone (F) in a randomized multicenter trial. Since February 1987 to July 1988, 133 patients with advanced gastric cancer have been prospectively randomized to receive either MF (methotrexate 100 mg/m2 i.v. push, 5-fluorouracil 600 mg/m2 i.v. drip over 15 minutes one hour after methotrexate and leucovorin 15 mg p.o. q 6 hrs x 2 beginning 24 hrs after methotrexate) of F (the same 5-fluorouracil as described for MF). Each treatment was repeated weekly x 5, then q 2 weeks. The two treatment arms were balanced for 17 clinical characteristics. The response rate was 17.9% (10 of 56 patients) in the MF arm and 1.9% (one of 53 patients) in the F arm (p less than 0.01). Median duration of response was 6.8 weeks (MF) and 6 weeks (F), respectively. Median survival time was 7.9 months (MF) and 7.3 months (F) on interim findings. Leukocytopenia and GI toxicity were significantly more common in patients receiving MF, but the degree was similar for both arms. Other side effects were minimal and no different. This schedule of MF is more effective than F in inducing remission for patients with advanced gastric cancer.

Mechanism of action of the synthetic imidazole compound YM 534 on human promyelocytic leukemia line HL-60 cells

The effects of a novel anti-cancer drug, YM 534 on human promyelocytic leukemia line HL-60 cells were investigated. The growth of the cells was completely inhibited with an IC50 of 2.5 X 10(-6) M. The incorporation of 3H-thymidine or 3H-uridine into acid insoluble fraction of the cells was completely inhibited at a 10(-4) M concentration of the drug. However, that of 3H-leucine was suppressed by only 32% at this drug concentration. The single strand scission of DNA of the cells as revealed by alkali sucrose density gradient centrifugation was induced by YM 534 at a 10(-4)M concentration for 60 min. When PM2 DNA in a cell-free system was examined in the presence or absence of reducing agent, no damage to DNA was observed at a 10(-4)M YM 534. The processing of preribosomal to ribosomal RNA of HL-60 cells was retarded at a 10(-5) M level of the drug.

[Experimental studies on the antitumor effect of progesterone and enhancement of the therapeutic effect of anticancer drugs by progesterone--from the aspect of zinc metabolism]

Since zinc is essential for the proliferation of tumor cells, the growth of tumor cells is suppressed in the zinc deficient condition. Thus, administration of progesterone, which decreases zinc uptake of tumor cells, to tumor bearing rats may inhibit the tumor growth. From this aspect, the antitumor effect of progesterone alone, or in combination with various anticancer drugs was investigated in the rats bearing Yoshida sarcoma (YS) or ascites hepatoma 109A (AH 109 A). In YS bearing rats, a significant inhibition of the tumor growth in size was observed by progesterone, and a slight inhibition of the tumor growth in AH 109 A bearing rats. A decreased zinc content of YS cells was also observed in YS bearing rats given progesterone in comparison with that of control rats. In combination of progesterone and anticancer drugs, the antitumor effect of methotrexate or vincristine was markedly enhanced by progesterone in YS bearing rats.

The mechanism of action of quinocarmycin citrate (KW 2152) on mouse L1210 cells in vitro

The effects of the antitumor antibiotic, quinocarmycin citrate (KW 2152), on L1210 cells were studied in vitro. The cellular growth was completely inhibited at 10(-6) M KW 2152, and after 2 days no viable cell was seen. The incorporation of 3H-thymidine, 3H-uridine, or 3H-leucine into the acid-insoluble fraction was not affected at 10(-4) M for 1 h; however, when the cells were treated with 10(-6) M for 24 h, the radioactivity appearing in the acid-insoluble fraction was reduced to 20%, 30%, and 48%, respectively, of the control. The single strand scission of the DNA of L1210 cells was seen at 10(-7) M for 24 h, as revealed by an alkaline, sucrose density gradient. However, no damage to plasmid pBR322 was observed even at 10(-6) M KW 2152 for 24 h, as revealed by 0.8% agarose gel electrophoresis, indicating that some soluble factors of the cells might contribute to the damage to the DNA of L1210 cells. The processing of pre-rRNA of the cells was not inhibited at 10(-6) M of the drug for 24 h of incubation.

[An experimental study on SRCA (subrenal capsule assay)--using immunosuppressive maneuvers]

Six-day SRCA using normal mice developed by Bogden et al. is one of the most promising methods for in vivo chemosensitivity tests. However, this method has a problem on the influence of the host reaction during six days. Therefore, we examined the tumour growth kinetics, host reaction and expression of antitumor effect on three immunosuppressive maneuvers; cyclophosphamide (EX), cyclosporin A (CSA), and total body irradiation (TBI). The tumour diameter increased until day 16 in EX and CSA-treated groups and day 10 in TBI-treated group, but the results of the histological examination showed that tumour cells were preserved in tissue on day 14 in CSA-treated group and day 6 in EX and TBI-treated groups. These results were supported by flow cytometrical analysis. The autoradiogram using 3H-TdR showed that labelling index of the tumour cells was not affected by these immunosuppressive maneuvers. From the investigation of the antitumour activity of adriamycin and mitomycin C, it was suggested that the 12-day assay was suitable if nude mice were used in SRCA, and six-day assay, if EX-treated normal mice were used. In CSA-treated group, toxicity of anticancer drugs was manifested than usual.

Inhibitory effects of prostaglandin A2 on c-myc expression and cell cycle progression in human leukemia cell line HL-60

The effect of prostaglandin A2 (PGA2) on c-myc expression was investigated in a human promyelocytic leukemia cell line, HL-60, which responded to PGA2 with a dose-dependent growth inhibition. Northern blot analysis indicated that treatment with PGA2 at 0.5 to 5.0 micrograms/ml remarkably reduced the steady state level of c-myc mRNA within 3 h, and then it gradually recovered according to the order of concentration of the drug. In contrast to c-myc, the level of class I HLA mRNA, as an internal control, was not diminished by PGA2 treatment. Further, this reduction of c-myc was not disturbed by cycloheximide, suggesting that this PGA2 action on c-myc expression is independent of de novo protein synthesis. Cytofluorometric analysis revealed that the exposure of HL-60 cells to PGA2 at 0.5 or 5.0 micrograms/ml arrested the cells in the G0-G1 phase of the cell cycle. This accumulation of the cells in G0-G1 phase continues until 24 or 36 h at 0.5 or 5.0 micrograms/ml, respectively. The G0-G1 arrest of the cell cycle was also recovered as the inhibition of c-myc was released. This recovery may be due to the loss of activity of PGA2 in culture medium. This study clearly showed that PGA2 treatment arrested HL-60 cells in the G0-G1 phase of the cell cycle and was associated with the reduction of c-myc mRNA.

[Mechanism of action of anti-cancer drugs from the viewpoint of RNA metabolism]

The mechanism of action of anti-cancer drugs, especially 5-FU, was discussed on the basis of RNA metabolism. After its incorporation into cells, 5-FU is metabolized through the uracil pathway, and finally incorporated into various species of RNA. On the other hand, 5-FU metabolized to FdUMP forms a covalent ternary complex among TS and mTHF, and inhibits de novo TMP synthesis, resulting in the inhibition of DNA synthesis. However, 5-FU was found to exert an effect on TS- mutant FM3A cells which was almost as lethal as the effect on wild-type FM3A cells in the presence of thymidine. Therefore, this lethal effect could be attributable to the inhibition of RNA metabolism, rather than DNA metabolism. The effects of 5-FU on RNA metabolism in L1210 cells are as follows: (1) inhibition of the processing of preribosomal RNA to ribosomal RNA (2) inhibition of the synthesis of poly(A) RNA of mRNA (3) inhibition of tRNA methylation (4) impaired synthesis of snRNA, U4, U6. (5) inhibition of pre-rRNA methylation (6) enhancement of poly(A) RNA translation. With reference to the items listed above, a discussion was made on the basis of our experimental results.

[An experimental study on SRCA (subrenal capsule assay)--comparison of the test between normal and nude mice]

Six-day SRCA using normal mice developed by Bogden et al. is a promising in vivo chemosensitivity test. However, this method has a problem on the influence of the host reaction. We compared the tumor growth kinetics and host reaction between normal and nude mice. The tumor diameter increased until day 6 in normal and day 16 in nude mice, but the histological finding revealed many host reactive cells and few viable tumour cells on day 6 in normal mice, and well preserved tumour cells on day 16 in nude mice. These results were supported by flow cytometrical analysis. Autoradiogram using 3H-TdR showed a recovery of labeling index to the steady label by day 1. This index was similar between normal and nude mice. When antitumor activity of adriamycin, cisplatin or mitomycin C was compared with nude mice system, the order of effectiveness was the same as the system using nude mice implanted tumor cells subcutaneously and given the drugs intraperitoneally, but different in normal mice.

Responsiveness of peripheral blood lymphocytes from cancer patients and healthy donors to interleukin-2 (IL-2)

The proliferative response of the peripheral mononuclear cells (MNC) from cancer patients and healthy individuals to IL-2 was studied by use of the quantitative microwell assay of the 3H-TdR incorporation into the cells in vitro. After the addition of phytohemagglutinin (PHA), MNC acquired the reactivity to IL-2 within 3 hr, and reached a maximum after 12 to 17 hr of incubation. Although the IL-2 response of PHA-activated MNC from cancer patient was lower than that from healthy donor, there was no significant difference in the kinetics of proliferation. The maximum response of PHA-activated MNC from both cancer patients and healthy donors to IL-2 was observed at 96 hr and 84 hr, respectively. When monocytes were removed from MNC, IL-2-associated growth of the remaining fraction of MNC was decreased to 40-70% in both cancer patients and healthy donors. Furthermore, monocytes from cancer patients did not affect the IL-2 responsiveness of lymphocytes from healthy donors, and vice versa. The number of T lymphocytes having IL-2 receptors (IL-2R) from cancer patients was lower than that from healthy donors. These facts indicated that the lower IL-2 response of MNC from cancer bearer was due to the decreased number of T lymphocytes possessing IL-2R, and not due to monocytes themselves.

Pharmacokinetic studies on 1-(2-chloroethyl)-3-isobutyl-3-(beta-maltosyl)-1-nitrosourea (TA-077). III. Pharmacokinetics of a new nitrosourea antitumor agent TA-077 in humans (a phase I study)

A new nitrosourea antitumor agent TA-077, 1-(2-chloroethyl)-3-isobutyl-3-(beta-maltosyl)-1-nitrosourea, was intravenously administered to 15 cancer patients at doses ranging from 7 to 100 N (1 N = 30 mg/m2) in a phase I clinical trial. Time courses of blood concentrations of TA-077 and its active metabolite TA-G, 3-beta-D-glucopyranosyl analog of TA-077, were followed. The TA-G concentration reached a maximum at 7.0 +/- 2.3 min, and decreased thereafter with a half-life of 12.9 +/- 2.8 min. The time-course patterns and various pharmacokinetic parameters of TA-077 and TA-G were similar to those in the guinea pig, which, like humans, lacks plasma maltase activity. The 2 h-urinary excretion rate of TA-G in the above patients ranged from 0.15 to 7.7% of the dose. The areas under the concentration-time curve and maximal concentration values were both linearly correlated to the dose with correlation coefficients of 0.78 and 0.82, respectively. Repeated administration of TA-077 (29 to 40 N) for 5 or 6 consecutive days did not affect the pharmacokinetic parameters of TA-077 and TA-G in 7 cancer patients except for slight increases in the half-life and area under the curve of blood TA-G.

[Phase I study of natural interferon-gamma]

We report a clinical study of toxicity and pharmacokinetics of intravenously administered natural interferon-gamma. Twenty three cases with metastatic cancer were given interferon-gamma at doses of 10 X 10(4)-400 X 10(4) IU in single injection. Another twenty three cases were administered at doses of 5 X 10(4)-50 X 10(4) IU/day every day for thirty days. Side effects associated with natural interferon-gamma administration were qualitatively similar to those previously reported for alpha, and beta interferon treatment. After intravenous injection, interferon-gamma was cleared monoexponentially with a short half-life of 120 minutes from the circulation. One case with disseminated thyroid cancer showed minor response.

[Sequential methotrexate-5-fluorouracil (MTX-5-FU) treatment of patients with advanced gastric and colorectal cancer. Sequential Methotrexate-5-FU Study Group]

A multicenter cooperative study was conducted from July 1984 to March 1986 to evaluate the clinical efficacy of sequential MTX-5-FU treatment in 96 cases of advanced gastric cancer and 39 cases of colorectal cancer. 5-FU 600 mg/m2 i.v. was given and MTX 30 mg/m2 (A), 100 mg/m2 (B) and 300 mg/m2 (C) i.v. were given, and the administration interval between MTX and 5-FU was 1 to 3 h for the gastric cancer group, and 7 h for the colorectal cancer group. Leucovorin rescue of 10 mg/m2 p.o. was given 24 h after MTX administration. In the gastric cancer group, the response rate for Regimen A was 23.2% (CR 1 and PR 12) out of 56 evaluable cases, and for Regimen B, 40.5% (CR 1 and PR 14) out of 37 evaluable cases. In the colorectal cancer group, the response rate for Regimen A was 28.6% (PR 6) out of 21 evaluable cases and for Regimen B, 20.0% (PR 3) out of 15 cases. Median survival time for the gastric cancer group was 5.5 months with Regimen A and 7.6 months with Regimen B, and for the colorectal cancer group 10.9 months with Regimen A and 7.9 months with Regimen B. Main adverse effects were marrow impairment and gastrointestinal symptoms such as nausea, diarrhea, and stomatitis. In this study Regimen B showed relatively good results. In order to evaluate the biochemical modulation occurring with sequential MTX-5-FU treatment, a further phase III study in gastric cancer patients should be conducted.

[A phase I trial of idarubicin by oral administration]

A phase I trial of a new anthracycline derivative, idarubicin, was conducted in 16 patients with various advanced solid tumors. Doses administered were 20, 30 and 40 mg/m2 with single oral doses. Dose-limiting factors were both leukopenia and thrombocytopenia reaching a nadir about 2 weeks after the start of treatment and requiring 7 to 10 days for recovery. Other toxicities were anorexia, nausea and vomiting, but alopecia did not occur. The maximum tolerated dose was judged to be 40 mg/m2 and the recommended dose for phase II trials was determined to be 30-35 mg/m2.