Leucovorin rescue from raltitrexed (tomudex)-induced antiproliferative effects: in vitro cell line and in vivo mouse studies.

Raltitrexed (RTX) is an antifolate thymidylate synthase (TS) inhibitor that is effective for the treatment of advanced colorectal cancer and other solid tumors. However, a small minority of patients receiving RTX monotherapy will experience grade III/IV gastrointestinal toxicity that can be life-threatening, particularly if copresenting with neutropenia. Lack of vigilance in recognition and treatment of symptoms of toxicity or violations of protocol have led to treatment-related deaths in some hospitals. The safety of RTX could be improved if an effective rescue agent was available. Leucovorin (LV) is a reduced folate cofactor that competes with RTX for transport and polyglutamation in both tumor and normal tissues and thus has potential as a rescue agent. In vitro cell studies are presented suggesting that the growth-inhibitory, and potentially cytotoxic, effects of RTX on populations of viable cells can be reversed by the delayed administration of LV. The mechanisms involved are inhibition of further drug uptake and polyglutamation and a redistribution and/or reduction in the concentration of preformed raltitrexed polyglutamates. A more clinically relevant in vivo mouse model was used to test the hypothesis further. BALB/c mice treated with 100 mg/kg/day x 4 days of RTX were used as a model for gastrointestinal and bone marrow toxicity. LV (200 mg/kg), which was given after the onset of severe weight loss and diarrhea (twice daily, days 5-7), prevented further weight loss and induced earlier recovery. This was accompanied by improvement in the histological appearance of the intestine (day 7) and the concentration of neutrophils and platelets in the blood (day 9). BALB/c mice could not tolerate 100 mg/kg daily x 5 days unless LV (200 mg/kg twice daily) was given on days 6-8. Measurement of RTX (polyglutamates) by RIA after 100 mg/kg RTX daily (days 1-4) showed less drug in plasma (3-4-fold), liver (8-11-fold), kidney (3-4-fold), and small intestinal epithelium (3-4-fold) on day 7 in LV-treated mice (100 or 200 mg/kg twice daily) compared with controls. A single injection of 100 mg/kg RTX (day 1) gave plasma levels of 3-4 pmol/ml on day 4 that are more clinically relevant. Administration of LV (100 or 200 mg/kg; twice daily on days 4-6) reduced the RTX concentration in the liver 2-4-fold on days 7, 9, and 11 compared with controls. A model is proposed where LV and/or its anabolic products can compete with RTX uptake into tissues and interfere with the homeostatic regulation of RTX polyglutamates. These data support the use of LV rescue in the small minority of patients treated with RTX who present with a severe pattern of antiproliferative toxicities. The use of LV is not recommended routinely because the antitumor activity of RTX may similarly be reversed.     

The importance of p53-independent apoptosis in the intestinal toxicity induced by raltitrexed (ZD1694, Tomudex): genetic differences between BALB/c and DBA/2 mice.

The thymidylate synthase inhibitor raltitrexed (ZD1694, Tomudex) induces greater intestinal toxicity, manifested as diarrhea and weight loss, in BALB/c than in DBA/2 mice. No convincing pharmacokinetic or pharmacodynamic reason for this strain difference has been established. We have investigated whether this strain difference in response to raltitrexed is related to differential susceptibilities of intestinal mucosae to undergo apoptosis and also whether p53 expression, a critical factor in 5-fluorouracil-induced intestinal apoptosis and toxicity, modulates this response. Ten mg/kg or 100 mg/kg raltitrexed were administered as single or double i.p. injections 24 h apart to BALB/c, DBA/2, and p53-/- mice. Apoptosis, mitosis, and tissue damage were assessed in intestinal epithelium, and animal weight was recorded. BALB/c mice developed diarrhea and weight loss following 100 mg/kg x2 raltitrexed, whereas DBA/2 mice did not. BALB/c mice were more sensitive than DBA/2 to induction of small-intestinal and colonic apoptosis 24 h following 100 mg/kg raltitrexed. Inhibition of mitosis was equivalent in both strains. Both strains showed histopathological damage to the small intestine after 100 mg/kg x2 raltitrexed, but only BALB/c mice demonstrated colonic damage. p53-null mice showed the same level of small intestinal apoptosis as their wild-type counterparts 24 h after 100 mg/kg x1 raltitrexed and also the same levels of intestinal toxicity 3, 5, and 7 days after 100 mg/kg x2 raltitrexed. Thus, BALB/c mice were more susceptible to induction of intestinal apoptosis by raltitrexed than DBA/2 mice and also demonstrated more histopathological damage in the colon correlating with the induction of diarrhea and weight loss. In contrast to 5-fluorouracil, the intestinal apoptosis and toxicity induced by raltitrexed were p53-independent.     

Recombinant human epidermal growth factor accelerates recovery of mouse small intestinal mucosa after radiation damage

PURPOSE: To determine whether systemically administered recombinant human epidermal growth factor (rhEGF) accelerates the recovery of mouse small intestinal mucosa after irradiation. METHODS AND MATERIALS: A mouse mucosal damage model was established by administering radiation to male BALB/c mice with a single dose of 15 Gy applied to the abdomen. After irradiation, rhEGF was administered subcutaneously at various doses (0.04, 0.2, 1.0, and 5.0 mg/kg/day) eight times at 2- to 3-day intervals. The evaluation methods included histologic changes of small intestinal mucosa, change in body weight, frequency of diarrhea, and survival rate. RESULTS: The recovery of small intestinal mucosa after irradiation was significantly improved in the mice treated with a high dose of rhEGF. In the mice that underwent irradiation without rhEGF treatment, intestinal mucosal ulceration, mucosal layer damage, and severe inflammation occurred. The regeneration of villi was noticeable in mice treated with more than 0.2 mg/kg rhEGF, and the villi recovered fully in mice given more than 1 mg/kg rhEGF. The frequency of diarrhea persisting for more than 3 days was significantly greater in the radiation control group than in the rhEGF-treated groups. CONCLUSIONS: Systemic administration of rhEGF accelerates recovery from mucosal damage induced by irradiation. We suggest that rhEGF treatment shows promise for the reduction of small intestinal damage after irradiation.     

Prevention by chitosan of myelotoxicity, gastrointestinal toxicity and immunocompetent organic toxicity induced by 5-fluorouracil without loss of antitumor activity in mice.

We examined the antitumor activity and side effects (myelotoxicity, immunocompetent organic toxicity and gastrointestinal toxicity) of combined treatment with the cancer chemotherapy drug 5-fluorouracil (5-FU) and dietary fiber chitosan in sarcoma 180-bearing mice. 5-FU (12.5 mg/kg x 2/day) plus chitosan (150, 375 and 750 mg/kg x 2/day) inhibited the tumor growth as well as 5-FU alone. Chitosan (150 and 750 mg/kg x 2/day) blocked the reduction of blood leukocyte number caused by 5-FU administration, and it prevented the injury of the small intestinal mucosa membrane and delayed the onset of diarrhea induced by 5-FU. Furthermore, chitosan (750 mg/kg x 2/day) prevented the reduction of spleen weight induced by 5-FU in sarcoma 180-bearing mice, and the reduction of lymphocyte and CD8+ T cell numbers induced by 5-FU was also prevented by the oral administration of chitosan (750 mg/kg x 2/day) in C57BL/6 mice. Chitosan (150 and/or 750 mg/kg x 2/day) reduced the 5-FU incorporation into RNA fractions of small intestine and spleen without affecting the 5-FU incorporation into the tumor in sarcoma 180-bearing mice. These findings suggest that prevention of the 5-FU side effects by chitosan might be partly due to the selective inhibition of 5-FU uptake into the small intestine and spleen, resulting in the reduction of immune function toxicity, myelotoxicity and gastrointestinal toxicity of 5-FU. Therefore, it is concluded that the combination of chitosan and 5-FU might be useful for the prevention of side effects such as gastrointestinal toxicity, immunotoxicity and myelotoxicity caused by 5-FU.     

Sodium hydrogen-S-(3-amino-2-hydroxypropyl) phosphorothioate (WR-77913): toxicity and bone marrow radioprotection

Experiments have been carried out to compare the toxicity and radioprotective effect of sodium hydrogen-S-(3-amino-2-hydroxypropyl) phosphorothioate (WR-77913) with those of S-2-(3-aminopropylamino)ethyl phosphorothioic acid (WR-2721). The drugs were given intraperitoneally to 12 week-old female BALB/c mice 30 minutes before whole body irradiation. Lethality at 30 days was the endpoint used. The drug LD50/30 was 678 mg/kg for WR-2721 and 3574 mg/kg for WR-77913. The LD50/30 for WR-77913 combined with 500 mg/kg of WR-2721 was 3328 mg/kg. The LD50/30 for misonidazole was 380 mg/kg when given in combination with 500 mg/kg of WR-2721 and 801 mg/kg when combined with 2200 mg/kg of WR-77913. Protection of bone marrow by WR-77913 and WR-2721 was comparable at doses close to the maximum tolerable dose (MTD, drug dose lethal to 10% of the animals at 30 days), but WR-77913 gave better protection at 35% of the MTD. These characteristics of low toxicity, non-additive toxicity with WR-2721, less toxicity in combination with misonidazole and adequate bone marrow protection at 25% of the MTD, make WR-77913 a protector worthy of further investigation.     

Preclinical evaluation of the anticancer activity and toxicity of 9-nitro-20(S)-camptothecin (Rubitecan).

The purpose of this study is to establish the maximum tolerated dose of rubitecan in mice, dogs and men and to establish the anticancer activity of such dose against human tumors xenografted in nude mice. Nude mice received increasing doses of Rubitecan by intrastomach injection until the maximum tolerated dose (MTD) had been established for both the single dose and the multiple doses at the schedule of 5 days on, 2 days off. Extrapolating from the mouse data, MTD was determined for oral administration in dogs and man. Levels of the drug in plasma were determined by high pressure liquid chromatography (HPLC). Using maximum tolerated multiple doses, the sensitivity of human cancer xenografts in nude mice to Rubitecan was determined. MTD of Rubitecan in mice for multiple doses intrastomach at the schedule of 5+,2- was 1 mg/kg/day. MTD in dogs was also 1 mg/kg/day, administered orally but at the schedule of 4+,3-. In man, it was 1 mg/m2/day at the schedule of 5+,2-. Treatment of human cancer xenografts in nude mice with MTD of Rubitecan resulted in 100% growth inhibition of 30/30 tumors tested and in 24/30 in their total disappearance. These 30 tumors comprised all the most common human cancers: lung, colorectal, breast, pancreatic, ovarian, prostate, stomach, melanoma and a leukemia. From the data collected, it appears that rubitecan is a very promising anticancer drug with high potency against a wide spectrum of human cancers. These cancers growing as xenografts in nude mice are always growth inhibited (30/30) and frequently (24/30) totally destroyed by the administration of non-toxic doses of Rubitecan.     

A phase I clinical, pharmacological, and biological trial of interleukin 6 plus granulocyte-colony stimulating factor after ifosfamide, carboplatin, and etoposide in children with recurrent/refractory solid tumors: enhanced hematological responses but a high incidence of grade III/IV constitutional toxicities.

A Phase I trial was conducted to determine the safety, biological activity, and hematopoietic recovery by the combination of interleukin 6 (IL-6) and granulocyte-colony stimulating factor (G-CSF) after myelosuppressive chemotherapy in children. Patients <22 years of age at diagnosis with either recurrent or refractory solid tumors received ifosfamide 1,800 mg/m2/day x 5 days, carboplatin 400 mg/m2/ day x 2 days, and etoposide 100 mg/m2/day x 5 days, followed by daily s.c. G-CSF (5 microg/kg/day) and IL-6 (2.5, 3.75, or 5.0 microg/kg/day). Pharmacokinetic, proinflammatory mediator levels, hematopoietic colony assays, and cytokine receptor expression studies were performed during course one. Nineteen patients were evaluable for toxicity and received IL-6 at doses of 2.5 (n = 8), 3.75 (n = 5), or 5.0 (n = 6) microg/kg/day. Dose-limiting constitutional toxicity occurred in two of six patients at 5.0 microg/kg/day, two of five patients at 3.75 microg/kg/day, and two of eight patients at 2.5 microg/kg/day. The maximum tolerated dose (MTD) exceeded the lowest dose tested. Because of lack of drug availability, an MTD was not established. The maximum concentration of IL-6 (2.5 microg/kg/day) was 0.799 +/- 1.055 ng/ml (mean +/- SD). During the first course, the median time to absolute neutrophil count > or = 1,000/mm3 and platelets > or = 100,000 mm3 was estimated at 19 and 23 days, respectively. Peripheral blood progenitor cells expressing receptors to IL-3, IL-6, and G-CSF increased significantly over baseline (P < 0.05). After the first dose of IL-6, IFN-gamma levels were abnormal in 13 patients, and IL-1beta levels were abnormal in 10 patients. IL-6 has a high incidence of constitutional toxicity and a lower MTD in children compared with adults. In vivo use of IL-6 in children after chemotherapy remains limited. However, IL-6 may be more optimally investigated in children under ex vivo conditions.     

Comparative study between daily and 5-days-a-week administration of oral 5-fluorouracil chemotherapy in mice: determining the superior regimen

BACKGROUND: Oral administration of derivatives of 5-fluorouracil (5-FU) is currently used to treat colorectal cancer in the United States. Oral chemotherapy possesses certain advantages: it is simple, easy to administer, and has few side effects. We compared conventional daily oral administration of 5-FU (daily schedule) with administration on 5 consecutive days followed by 2 drug-free days (5-days-a-week schedule) in a mouse tumor model. METHODS: The maximal tolerated dose (MTD) in the 5-days-a-week schedule and in the daily schedule were determined in 6-week-old non-tumor-bearing CDF1 male mice. In antitumor experiments, CDF1 mice were inoculated subcutaneously with Colon26 cells (1x10(6) per mouse). Antitumor efficacy was evaluated in terms of the ratio of tumor size in treated to control mice (T/C ratio). RESULTS: The MTD of 5-FU in the 5-days-a-week schedule was 42 mg/kg, and in the daily schedule was 29 mg/kg. In the 5-days-a-week schedule dose escalation nearly 1.4 times that in the daily schedule was possible, although the total dose over 7 days was similar between the two schedules (203 mg/kg and 210 mg/kg, respectively). When the doses of 5-FU were compared under the condition of no body weight loss, the 5-days-a-week schedule produced a comparative dose escalation of 2.1 times per day (from 20 to 42 mg/kg), and 1.5 times per total weekly amount (from 140 to 210 mg/kg) compared to the daily schedule. With regard to the antitumor effect as indicated by the T/C ratio, the 5-days-a-week schedule produced over 70% tumor suppression, whereas the daily schedule produced only 50% suppression at the MTD. Therapeutic efficacy was calculated in terms of the ratio of body weight change to antitumor effect (T/C ratio), and revealed that the MTD of 42 mg/kg 5-FU in the 5-days-a-week schedule produced a therapeutic efficacy almost three times that of the MTD of 29 mg/kg 5-FU in the daily schedule (P<0.001). CONCLUSIONS: Using oral administration of 5-FU, we confirmed that the 5-days-a-week schedule allowed dose intensity escalation and was superior to the daily schedule in both enhancement of antitumor effect and protection against adverse effects.     

5-Fluorouracil dose escalation enabled with PN401 (triacetyluridine): toxicity reduction and increased antitumor activity in mice

Purpose: PN401, an oral prodrug of uridine yields more bioavailable uridine than oral administration of uridine itself. PN401 may therefore be useful for permitting dose escalation of 5-fluorouracil (5-FU) with consequent improvements in antitumor efficacy. Experimental design: Female BALB/c mice (Colon 26 adenocarcinoma) were treated with 5-FU with PN401 to define the MTD, and pharmacokinetic analyses were done. A comparison of 5-FU/PN401 was made to 5-FU/eniluracil (EU) and 5-FU/LV. The best timing of the first dose of PN401 relative to 5-FU was evaluated by administering groups of mice PN401 beginning 2, 24, or 48 h after 5-FU dose. Results: The MTD of 5-FU was 100 mg/kg/week whereas the MTD of 5-FU + PN401 was 200 mg/kg/week. A complete response (CR) of 80% and partial response (PR) of 20% was observed with 5-FU (200 mg/kg) + PN401, CR of 40% and PR of 60% with 5-FU (175 mg/kg) + PN401, PR of 10% with 5-FU (150 mg/kg) + PN401 while no response with 5-FU (100 mg/kg) + PN401. Analysis of 5-FU pharmacokinetics displayed nonlinearity as a function of administered dose in mice. In the comparison study, the best response was achieved with PN401 when compared to EU and LV. Mice that did not receive PN401 died by day 12, while other groups were alive at day 31. The proportion of mice surviving was highest in the group which received PN401 at 2 h followed by 24 and 48 h. Conclusions: There is a threshold 5-FU dose after which the efficacy is dramatically improved—in mice bearing Colon 26 adenocarcinoma, that threshold is a dose of >150 mg/kg/week, and the increased efficacy correlates with about a fourfold increase in the AUC of 5-FU. PN401 used to rescue mice from the lethal toxicity of 5-FU entails that PN401 can be used as an antidote even when used up to 48 h after a 5-FU overdose.     

Schedule-dependent variations in the response of murine P388 leukemia to cyclophosphamide in combination with interferons-alpha/beta

Positive therapeutic effects of interferons (IFNs) in combination with other therapies will depend on defining modalities, doses, and timing of treatment in the setting of varied tumor burdens. When 10(4) P388 leukemia cells were inoculated i.p. on day 0 in BALB/c x DBA/2 F1 mice, all mice died within 18 days if left untreated. Murine IFN-alpha/beta (5 x 10(5) units) injected daily i.p. on days 5-9 resulted in 20% increase in life span (ILS) (P less than 0.0001). Cyclophosphamide (CY) (100, 33, or 15 mg/kg) was injected i.p. once 2 days before start (day 3), simultaneously with start (day 5), or 2 days after cessation of IFN treatment (day 11). When 100 mg/kg CY alone were injected on day 3 or 5, all mice survived more than 90 days and were considered cured. When IFN was given after this curative dose of CY, more tumor deaths occurred; up to 100% of the mice died when 100 mg/kg CY on day 3 were combined with IFN on days 5-9. Increased mortality with the combination was not due to added toxicity of CY and IFN since the mice developed abdominal tumors and ascites. Mice not inoculated with tumor cells and treated similarly suffered only a transient weight loss, had only moderate white count depression, and did not die. When IFN was injected before CY on days 1-5 (instead of days 5-9), IFN did not alter the effectiveness of CY (100 mg/kg on day 5). In contrast to these results, when CY (100 mg/kg) was administered on day 11, after IFN (days 5-9), an augmented survival occurred with 119% ILS and 40% cures (CY alone on day 11 resulted in 69% ILS but no cures). In addition, when CY at a lower dose of 15 mg/kg was injected in combination with IFN, survival was consistently augmented by IFN; e.g., CY alone on day 3 caused 40% ILS and with IFN (days 5-9) 60% ILS (P less than 0.0001). Qualitatively similar findings were obtained when P388 leukemia cells were inoculated s.c. and the drugs delivered i.p. Inhibition by IFN of antitumor effects of a second alkylating agent, 1,3-bis(2-chloroethyl)-1-nitrosourea, was also identified. Thus, IFN-alpha/beta potentiated suboptimal CY effects for P388 leukemia, had neutral effects when injected before CY treatment, and inhibited antitumor activity of curative CY or nitrosourea schedules.     

A Phase I trial of prolonged administration of lovastatin in patients with recurrent or metastatic squamous cell carcinoma of the head and neck or of the cervix

Squamous cell carcinomas of the head and neck (HNSCC) and of the cervix (CC) are particularly sensitive to the apoptotic effects of lovastatin in vitro. In this Phase I study, the safety and maximum related dose (MTD) of lovastatin was evaluated in these specific clinical settings. This was a Phase I open-label study to determine the recommended Phase II dose (RPTD) of lovastatin in advanced HNSCC or CC. This study involved a dose and duration escalation of lovastatin starting at 5/mg/kg/day x 2 weeks, every 21 days, until the MTD was reached. Plasma samples were collected for pharmacokinetic analysis. All 26 patients enrolled were evaluable. Dose-limiting toxicity (DLT) consisting of reversible muscle toxicity was seen at 10 mg/kg/day x 14 days. Toxicity may be related to relative renal insufficiency. The MTD was determined to be 7.5 mg/kg/day x 21 days, every 28 days. The low lipid levels experienced on study did not translate into adverse events. Biologically relevant plasma lovastatin levels were obtained. No objective responses were seen but the median survival of patients on study was 7.5 months (mean 9.2 +/- 1.5 months). Stable disease (SD) for more than 3 months was seen in 23% of patients. One patient achieved SD and clinical benefit for 14 months on study and a further 23 months off treatment. The disease stabilisation rate of 23% seen in these end-stage patients is encouraging. We conclude that the administration of lovastatin at 7.5 mg/kg/day for 21 consecutive days on a 28-day schedule is well tolerated in patients with good renal function and warrants further clinical evaluation.     

Chronic bioassay of benzyl chloride in F344 rats and (C57BL/6J x BALB/c)F1 mice

Benzyl chloride was administered to groups of 52 male and 52 female F344 rats and (C57BL/6J x BALB/c)F1 mice at two dose levels by gavage in corn oil three times a week for 2 years. Survivors were sacrificed a few weeks later and examined histopathologically. On the basis of a subchronic study at a range of doses, the doses of benzyl chloride in the chronic study were 100 and 50 mg/kg body weight for mice and 30 and 15 mg/kg body weight for rats. In mice of both sexes there was a high and statistically significant incidence of carcinomas and papillomas of the forestomach. In the livers of male mice, but not of females, there was a significantly increased incidence of hepatocellular neoplasms at the low dose but not at the maximally tolerated dose (MTD). In rats the only neoplasms showing a statistically significant increase compared with controls were C-cell neoplasms of the thyroid gland in females. A significant incidence of neoplasms was not found in the forestomachs of F344 rats, but it is possible that true MTD was not used for rats.     

Phase I dose escalation study of carboplatin to a fixed dose of irinotecan as first-line treatment of small cell lung cancer

BACKGROUND: Superiority of irinotecan (CPT-11) plus cisplatin over etoposide plus cisplatin in small cell lung cancer (SCLC) has recently been demonstrated. This study determines dose-limiting toxicity (DLT) and maximum tolerated dose (MTD) of escalating doses of carboplatin to a fixed dose of irinotecan in Caucasians with small cell lung cancer. PATIENTS AND METHODS: Patients with extensive small cell lung cancer received 50 mg/m(2) irinotecan on day 1, 8, and 15. Dose escalation of carboplatin on day 1 started in dose level 1 at an AUC of 5 mg x min/ml and was escalated to AUC 6 in level 2. Cycles were repeated on day 29. Dose escalation was evaluated after 3 consecutive patients. If no grade IV neutropenia lasting for > or =7 days or thrombopenia or non-hematologic toxicity > or = grade III occurred, treatment was continued in the next dose level. RESULTS: 16 patients were treated. DLT was reached in dose level 2 with 2 grade IV neutropenias and 1 grade IV thrombopenia and diarrhea. Toxicity was further investigated at dose level 1 in a total of 10 patients, which revealed 2 grade III neutropenias and 1 grade III diarrhea. Of 15 evaluable patients, 10 had a partial response, 3 had disease stabilization and 2 progressed. CONCLUSION: Dose level 1 was found to be MTD, this dose is currently compared to the combination of etoposide plus carboplatin within a randomised phase II/III trial.     

Combination effect of recombinant human interleukin 1 alpha with antitumor drugs on syngeneic tumors in mice

To investigate the combination effects of recombinant human interleukin 1 alpha (rHu IL-1 alpha) and antitumor drugs, groups of 7 mice bearing syngeneic tumors (Meth A sarcoma in BALB/c mice and colon 26 adenocarcinoma in BALB/c x DBA/2 F1 mice) were treated i.v. with the antitumor drugs according to the early (once daily on days 1, 4, 7, 10, and 13) and/or late (once daily on days 7, 10, 13, 16, and 19) medication schedules in combination with rHu IL-1 alpha administered i.m. at various timings (1 day before, concurrently with, and 1 day after every drug administration). Inhibition rates of the antitumor drugs (mitomycin C, doxorubicin, cisplatin, cyclophosphamide, and 5-fluorouracil) for both the murine tumors were more or less raised by coadministration of rHu IL-1 alpha irrespective of medication schedules and combination timings. After both early and late treatments with the optimal combinations of rHu IL-1 alpha (0.1-3 micrograms/mouse) and cisplatin (2-4 mg/kg) and by the late treatment with the optimal combinations of rHu IL-1 alpha (0.3-3 micrograms/mouse) and carboplatin (32 mg/kg) or thiotepa (4 mg/kg), many mice were completely cured of colon 26 adenocarcinoma and survived for more than 90 days. Combined use of rHu IL-1 alpha and antitumor drugs seems to be beneficial in antitumor chemotherapy.     

The raltitrexed-vinorelbine combination: a phase I pharmacokinetic and pharmacodynamic trial in advanced breast cancer

PURPOSE: Combinations of vinorelbine (VRB) and drugs targeting thymidylate synthase (TS) such as 5-fluorouracil (5-FU) have proven clinical efficacy in the management of advanced breast cancer. Raltitrexed (RTX) is a recent TS inhibitor which shows advantages over 5-FU in terms of a lower incidence of toxicity along with a simpler administration schedule. We conducted a phase I trial of the VRB-RTX combination in 12 patients with advanced breast cancer. MATERIALS AND METHODS: Most of the patients were refractory to taxane-anthracycline combination therapy. Their median age was 51 years (range 33-70 years). RTX was given on day 1 and VRB on days 1 and 5 on a 3-week cycle. Three dose levels were initially planned with VRB and RTX increasing from 22.5 to 25 mg/m(2) and from 2.5 to 3 mg/m(2), respectively. RESULTS: From a total of 50 cycles (mean 4 cycles per patient, range 1-11), the maximal tolerated dose (MTD) was reached at VRB 25 mg/m(2) and RTX 3 mg/m(2) with grade 3-4 neutropenia as the dose-limiting toxicity (7/16 cycles and 3/5 patients at the MTD). Nine pretreated patients were evaluable for treatment efficacy and three of these showed an objective response (one complete response, two partial responses; mean duration 26 weeks, range 17-38 weeks). Pharmacokinetic follow-up was done for both drugs (RTX by LC-MS-MS and VRB by HPLC-UV detection). There was no interaction between RTX and VRB pharmacokinetics since the VRB AUC was not significantly modified between day 1 and day 5. There was no relationship between RTX AUC and hematological toxicity. In contrast, there was a highly significant relationship between the mean VRB AUC (days 1-5) and the absolute neutrophil count decrease (Emax model, Hill constant=4.38+/-2.59, EC(50)=508+/-53.2 micro g.h/l, r=0.75, P=0.0013). A similar relationship was noted for the platelet decrease but at the limit of statistical significance. CONCLUSIONS: The VRB-RTX combination appears to be a valuable treatment option in second-line treatment of advanced breast cancer. It is deliverable on an outpatient basis, shows an acceptable toxicity profile potentially manageable by VRB pharmacokinetic follow-up, and has promising antitumor activity in taxane-anthracycline-refractory patients. The recommended dose for further studies is VRB 22.5 mg/m(2) and RTX 3 mg/m(2).     

Potentiation of chemotherapeutic activity by a Chinese herb medicine juzen-taiho-toh

Antitumor activity of Juzen-Taiho-Toh (JTX) and combination effect of JTX with antitumor agents were studied using murine tumors. In order to determine the antitumor activity of JTX, mice inoculated ip with IMC carcinoma (1 X 10(6) cells/CDF1 mouse), sarcoma-180(1 X 10(6) cells/ICR mouse) or Meth-A fibrosarcoma (1 X 10(6) cells/BALB/c mouse) were treated with JTX (12.5-50 mg/kg/day) ip on day 1 through day 10, and the survival days of mice were examined. Treatment with 25 mg/kg/day produced 38.7% increase of life span against IMC carcinoma. However, no antitumor effect was observed on solid form of these tumors by the daily treatment with JTX. Combination effect of JTX and antitumor agents was also examined. ICR mice inoculated sc with 1 X 10(6) cells of sarcoma-180 on day 0 were treated with JTX (2,000 mg/kg/day) po on day-7 through day 30. In addition, some of these groups received mitomycin C (5 mg/kg), cytoxan (67 mg/kg) or adriamycin (2.5 mg/kg) iv on days 3, 8 and 11, and the size of tumor grown in sc site was measured by a caliper. In combination with JTX, mitomycin C resulted in a significantly greater tumor growth inhibition than could be obtained with mitomycin C alone. Secondly, BALB/c or C57BL/6 mice inoculated sc with 1 X 10(4) cells of Meth-A fibrosarcoma or 1 X 10(5) cells of B16 melanoma on day 0 were treated with JTX (2,000 mg/kg/day) po on day 1 through day 30. Some of these group received ip with mitomycin C (3 mg/kg), adriamycin (2 mg/kg), 5-FU (33 mg/kg) or cytoxan (67 mg/kg) on days 3, 6, 9, 12, 15 and 18. From this result, the group treated with JTX and mitomycin C also showed a higher tumor-growth inhibition. Thus, a combination of a high dose of mitomycin C with JTX was more effective than mitomycin C alone.     

Combined treatments with vitamin A and 5-fluorouracil and the growth of allotransplantable and syngeneic tumors in mice

The combined effect of retinol palmitate (RP) and 5-fluorouracil (FUra) was examined with the use of allotransplantable and syngeneic murine tumor systems. The ip combined administration of RP (5,000 IU/kg/day) and FUra (5 mg/kg/day, 20 mg/kg/day, or 20 mg/kg/every 3d day) suppressed the tumor growth in ICR/JCL mice given sc inoculations of 5 X 10(6) allotransplantable sarcoma 180 cells and prolonged the survival time of mice inoculated ip with 10(7) tumor cells, as compared with the survival time of mice given the single administration of either RP or FUra. Similar results were obtained when BALB/c mice were inoculated sc with a syngeneic BALB/c Meth A fibrosarcoma and treated with RP (5,000 IU/kg/day) and FUra (20 mg/kg/every 3d day). The growth of Meth A implanted on day 10, as a rechallenge, was significantly suppressed in the group pretreated with RP alone or both RP and FUra for 9 days from day 1. The growth of Meth 1, another syngeneic tumor of BALB/c origin, inoculated on day 10 as a rechallenge tumor was unaffected by the treatment with RP and/or FUra. An immune response to tumor-specific antigens seemed to be involved in the combined effects of these two drugs.     

Anti-oxidant vitamins reduce normal tissue toxicity induced by radio-immunotherapy

Our purpose was to determine whether the administration of anti-oxidant vitamins could reduce dose-limiting toxicity from radio-immunotherapy (RAIT) and thereby allow higher escalation of RAIT doses. Lipophilic vitamins A and E were administered i.p. and hydrophilic vitamin C was administered i.m. for 14 days (3 days pre-RAIT through 11 days post-RAIT) alone or with bone marrow transplantation (BMT) to either BALB/c mice for toxicity studies or to nude mice bearing s.c. GW-39 human colonic cancer xenografts for therapy studies. The maximal tolerated dose (MTD) of RAIT ((131)I-MN14 anti-CEA IgG) that results in no lethality was determined for mice that did not receive vitamins or BMT and those that did receive one or both interventions. Body weight, peripheral white blood cell (pWBC) and platelet (PLT) counts and tumor growth were also measured. Administration of vitamins (equivalent of 3.5 IU/day vitamin A, 0.107 IU/day vitamin E and 4.0 mg/day ascorbic acid) to mice along with BMT increased the MTD by 42% and reduced body weight loss associated with RAIT. Vitamins also reduced the magnitude of RAIT-induced myelosuppression. As early as day 7 after RAIT, vitamins increased WBC counts following both a 400 microCi and a 500 microCi dose. On day 14 after the 400 microCi dose of RAIT (day 7 post-BMT), the additive effect of BMT and vitamin could be detected. Tumor growth was not adversely affected by vitamin administration.     

Involvement of nitric oxide on the pathogenesis of irinotecan-induced intestinal mucositis: role of cytokines on inducible nitric oxide synthase activation

Purpose

Intestinal mucositis and the closely associated diarrhea are common costly side effects of irinotecan. Cytokine modulators, such as thalidomide and pentoxifylline, are found capable of attenuating intestinal mucositis progression. Nitric oxide (NO) seems to be a key mediator of the antineoplastic drug toxicity. The aim of this study was to investigate the role of NO on the pathogenesis of intestinal mucositis, as well as the participation of cytokines upon inducible nitric oxide synthase (iNOS) expression in irinotecan-induced intestinal mucositis.

Methods

iNOS-knockout (iNOS^?/?) and C57BL/6 (WT, wild type) animals (n?=?5–6) were given either saline or irinotecan (60?mg/kg?i.p for 4?days), with or without pretreatment with aminoguanidine (50?mg/kg?s.c.), thalidomide (60?mg/kg?s.c), infliximab (5?mg/kg?i.v.), or pentoxifylline (1.7?mg/kg?s.c). On day 5, diarrhea was assessed, and following euthanasia, proximal intestinal samples were obtained for myeloperoxidase (MPO) and iNOS activity, morphometric analysis, western blot and immunohistochemistry to iNOS, cytokine dosage, and for in vitro evaluation of gut contractility.

Results

Irinotecan induced severe diarrhea and intestinal smooth muscle over-contractility, accompanied with histopathological changes. Additionally, increased MPO and iNOS activity and iNOS immunoexpression were found in WT animals treated with irinotecan. The rise in MPO, smooth muscle over-contractility, and diarrhea were abrogated in aminoguanidine-treated and iNOS^?/? mice. Moreover, through western blot, we verified that infliximab and pentoxifylline significantly inhibited irinotecan-induced iNOS expression. In addition, cytokine concentration was found only partially decreased in irinotecan-treated iNOS^?/? mice when compared with wild-type animals that were given irinotecan.

Conclusions

This study suggests a role of nitric oxide in the pathogenesis of irinotecan-induced intestinal mucositis and also provides evidence for the participation of cytokines on iNOS induction.     

Advantages in combination chemotherapy using cisplatin and its analogues for human testicular tumor xenografts

The antitumor effects and toxicities of combination chemotherapies using cisplatin (CDDP) and its analogues were compared with those of single drug therapies. Congenitally athymic nude BALB/c (nu/nu) mice were used to estimate antitumor activities of these compounds against human testicular tumor (Ht-14) xenografts and hetero-BALB/c (nu/+) mice were used to evaluate the toxic effects of the drugs. Combination therapy with half dosages of CDDP and carboplatin (JM8) (CDDP: 2, JM8: 20 mg/kg/day for 5 days), or of CDDP and (glycolato-O,O')-diammineplatinum (II) (254S) (CDDP: 2,254S: 4 mg/kg/day for 5 days), resulted in significant tumor regression. The combination of CDDP and JM8 had the highest therapeutic efficacy while the CDDP and 254S combination had a lower antitumor potency. In addition, the toxicities of the combination therapies were lower than what was produced by the highest dosage of CDDP (4 mg/kg/day for 5 days). These results demonstrated that the antitumor activities of these combination chemotherapies were equal or superior to the activity of CDDP or an analogue alone, and that the toxicities produced by these combinations were more manageable than those produced by single drug therapies.