Tolerability of approximately 30 anticancer drugs vary by 50% or more according to circadian rhythms in mice or rats. Despite pharmacokinetics parameters of cytostatic drugs vary according to dosing time in rodents, cellular rhythms appear as the main mechanisms of their chronopharmacology: circadian changes in enzymatic activities involved into fluoropyrimidine (5-fluorouracil-5-FU, or floxuridine-FUdR) catabolism (dehydropyrimidine dehydrogenase) or anabolism (thymidine kinase), rhythms in reduced glutathione, involved into cellular protection against cytotoxic effects of alkylating drugs, platinum complexes and anthracyclines, rhythms in cellular proliferation of rapidly renewing tissues, such as bone marrow or intestinal tract. Furthermore, chemotherapy injection at the least toxic time allows to increase its antitumor efficacy against several transplanted rodent tumor models. Extrapolation of these results for improving therapeutic index of chemotherapy in cancer patients was based upon the hypothesis that rhythms in metabolism or proliferation of healthy tissues were tightly coupled to the circadian sleep-wakefulness cycle, both in rodents and in man. Programmable-in-time pumps allowed to test the clinical relevance of chronotherapy principle in patients with cancer metastases. Phase I clinical trials with 5-FU, FUdR, oxaliplatin-L-OHP, interferon-alpha and doxorubicin suggested that circadian-based chronomodulation of chemotherapy delivery rate both improved drug tolerability and allowed to increase its safe dose. Antitumor activity of such chronomodulated regimens, usually involving several drugs, appeared as superior to that achieved by standard protocols in Phase II clinical trials, especially in patients with renal cell cancer receiving FUdR and in patients with colorectal cancer treated with 5-FU, folinic acid (FA) and L-OHP (so called chrono-FFL regimen). A randomized european multicenter trial validated the clinical relevance of the chronotherapy principle in 278 patients with metastatic colorectal cancer: chrono-FFL was compared to flat FFL infusion and resulted in 2 to 10 times fewer severe toxic effects and a near-doubling of its antitumor efficacy, objective response rate being 51% with chrono-FFL and 30% with flat FFL (p < 0.001). These results have warranted to test further the relevance of chronotherapy in patients with breast, lung or pancreatic cancer metastases and to develop basic research on the role of biological rhythms upon cancer processes.

Originally developed against the effects of ionizing radiations, amifostine is an organic thiophosphate compound shown able to selectively protect normal tissues against cytotoxic agents in cellular and animal models, without protecting tumor tissues. Amifostine is a prodrug which is dephosphorylated into its active metabolite, a free thiol derivative, by membrane alkaline phosphatase of the target issue. This unique metabolism supports its cellular selectivity and its preferential uptake by normal tissues. In phase II clinical trials, a decreased toxicity has been demonstrated in patients given alkylating agents; however, reduction of the response has not been observed. On the basis of these results, a prospective, randomized, phase III study has been conducted in patients with ovarian carcinoma receiving a combination of cisplatinum and cyclophosphamide. A significant decrease in hematologic, renal and neurologic toxicity was observed in the amifostine-treated patients compared with the control group, and response rates did not significantly differ between the two groups. Insufficient or emerging data are only available for other applications, including either in vitro manipulation of hematopoietic grafts or in vivo treatment of non-Hodgkin's lymphoma, head and neck carcinoma, non-small cell lung cancer and radioprotection. No data are yet available in regard to the potential protective effects of amifostine against mutagenicity and cancerogenicity of both chemo- and radiotherapy.

To assess efficacy and toxicity of less toxic analogs for advanced breast cancer in elderly women, we performed a phase II study using the combination mitoxantrone (MTZ)-vinorelbine (VNR). From January 1991 to May 1993, 25 women older than 70 years received a chemotherapy consisting in 10 mg/m2 of MTZ on day 1, followed by 20 mg/m2 of VNR on day 1 and 8. Cycles were repeated every 21 days for a maximum of ten cycles in the case of an objective response. Sixteen women previously received first line hormonotherapy, eight with only one metastatic site. Twenty-three patients are evaluable for response and toxicity. An objective response was observed in five cases (22%), with a median time to progression of 13 months. More than 75% of the planned dose-intensity, for MTZ and VNR was received by 90 and 57.2% of patients, respectively. Dose-limiting toxicity was myelosuppression but no febrile neutropenia was observed. Extra haematologic toxicities were unfrequent. This combination is well tolerated by elderly women, but best results could be achieved by increasing delivered dose intensity.

The goal of this study was to determine the effectiveness and potential indications of cardiopulmonary resuscitation (CPR) in medical cancer patients. A retrospective analysis of the records of patients admitted between November 1985 and January 1992 in the medical ICU of a cancer hospital and having had cardiac arrest was performed. Cardiac arrest occurred in 49 cancer patients. CPR was successful in 19 (39%), but only 5 (10%) were discharged alive from the hospital. CPR was successful in all eight patients in which cardiac arrest was the consequence of an acute cardiovascular drug toxicity, even if cancer was metastatic and treatment intent not curative, while it was effective in only 25% of those in which cardiac arrest was an ultimate complication of various problems, like septic shock or respiratory failure complicating the neoplastic disease. In cancer as in other types of disease, CPR is mainly indicated when cardiac arrest is the consequence of and acute insult.

Medullary thyroid carcinoma (MTC) is frequently resistant to chemotherapy. In this work, we have studied the effect of cisdiamminedichloroplatinum (II) (CDDP) in six MTC human cell lines and we have tried to reverse the resistance to CDDP with amphotericin B (AmB). We also studied the metabolism of glutathione (GSH) and the presence of the glutathione-sulfotransferase pi (GST pi) mRNA in the MTC cell lines. The cisplatin-induced cytotoxicity was evaluated with the 3-4,5 dimethylthiazol-2,5 diphenyl tetrazolium bromide (MTT) test, the neutral red (NR) uptake and with total GSH measurement in six cell lines, TT cell line and five cell lines that we isolated. The cultures were performed with or without AmB (5 micrograms/mL). Intracellular GSH was measured in TMC cells and compared to the levels obtained in six normal thyroid tissues. The expression of GST pi mRNA was evaluated by Northern blotting in the different cell lines. A CDDP-induced cytotoxicity was obtained in the six cell lines at doses inhibiting 50% of the cellular proliferation (IC50) varying from 6 to 40 micrograms according to the tests and the cells tested. A low concentration of AmB (5 micrograms/mL) potentiated the cisplatin toxicity after a 48-h coincubation of TMC in all cases. GSH levels in TMC cell lines were identical to those found in normal cells. GST pi mRNA was detected in all the TMC lines, except in TT cell line. In conclusion, CDDP was toxic for all the TMC cell lines and AmB potentiated this antitumoral effect. On the contrary, GSH and GST pi do not seem to be involved in the mechanisms of the resistance in these cell lines.

Investigation of Strychnos (Loganiaceae) shrubs and trees was initiated by their traditional uses of their inherent poisons on arrows: this led to the discovery of strychnine and curare alkaloids. Subsequently, phytochemical investigation of several Strychnos species has shown great structural diversity of the alkaloid constituent which also display various biological effects, i.e. convulsive and relaxant effects on muscles, and antimicrobial, antitumor and antihypertensive properties. Ethnobotanical field work conducted in different regions of Madagascar revealed that infusion of three Strychnos species, S. mostueoides, S. myrtoides and S. diplotricha, is used in association with subcurative doses of chloroquine to treat chronic malaria. Bioassayfractionation led to the isolation of two major bioactive components, strychnobrasiline and malagashanine. Whereas strychnobrasiline is a previously known chemical compound, malagashanine is the first in a series of a new subtype of Strychnos alkaloids. These two alkaloids are devoid of intrinsic antimalarial effects, both in vitro (IC50 = 73.0 micrograms/ml for strychnobrasiline and 69.1 micrograms/ml for malagashanine) and in vivo (10 mg/kg conferred a 5% suppression of parasitemia). When these alkaloids are combined with chloroquine at doses much lower than required for antiplasmodial effects, they greatly enhance the chloroquine action in a dose dependent manner as seen by the isobologram method. Several minor alkaloids structurally related to malagashanine were also isolated from Madagascan Strychnos. They all enhance, to greater or lesser degrees, the chloroquine effectiveness. Interestingly, there is a positive correlation between the ethnomedical use of the three Strychnos species as chloroquine adjuvants and the chloroquine-potentiating effects of malagashanine and strychnobrasiline isolated from them. After preliminary toxicological studies, infusion of stem barks of S. myrtoides in association with chloroquine was successfully evaluated in a clinical setting. Additional chemical, pharmacological and toxicological work is being conducted on these alkaloids with the aim of developing purified and standardized extracts for clinical trials. These trials will be carried out in the chloroquine-resistant regions of Madagascar which are in need of inexpensive and efficient drugs for the treatment of chloroquine-resistant malaria.

Camptothecin (CPT), an alkaloid isolated from the stem wood and bark of Camptotheca acuminata native to China, was discovered in the early 60's after a systematic screening of natural products by the National Cancer Institute (NCI). This new anticancer agent displays an unique mechanism of action as it inhibits intranuclear enzyme topoisomerase 1, involved in DNA replication. CPT is poorly water soluble and causes severe and unpredictable toxicities such as haemorrhagic cystitis and diarrhea; for therefore reason, a number of analogues have been synthetized in a attempt to define the features of the molecule that are essential for cytotoxicity and to produce derivatives with increased solubility. Clinical trials of several soluble molecules are in progress in the different countries: irinotecan, topotecan, 9-AC. Encouraging results are observed against solid tumors. Irinotecan was recently commercialized in France. It is a prodrug; the active metabolite SN-38 showed a good activity in metastatic colorectal adenocarcinoma; the limiting toxicities are myelotoxicity and essentially late diarrhea. However, new studies are needed for state precisely the optimal schedule of administration and association with other chemotherapeutic agents.

The deleterious effects of chimio or radio-therapy on spermatogenesis of men treated for testicular cancer are well known. Retroperitoneal lymphadenectomy is a risk for ejaculation process. Semen cryopreservation seems to be obligatory before any deleterious treatment. Prophylactic measures do exist such as lead protection during x-rays therapy, drugs with less toxicity but similar efficiency, selective lymphadenectomy. Moreover, positive results were reported form realised in animals to protect spermatogenesis. In men treated for testicular cancer, 4 protective studies were reported using either GnRH analogs (3 studies) or medroxyprogesterone (one study). No protective effects were obtained in these trials, and the reasons for such failure are discussed. Finally, new potential possibilities of spermatogenesis protection are suggested supported by the results of animal experiments or the occurrence of new drugs such as use of steroids, GnRH antagonist or testicular hypothermia.

The pathology of drug-induced pulmonary toxicity in children is poorly understood and probably under-estimated, in the absence of any prospective studies evaluating in a systematic fashion the side effect of medication on the respiratory apparatus. The pulmonary toxicity of thoracic irradiation has markedly receded with more restricted indications for this sort of treatment. Three clinical patterns are most commonly encountered in drug induced lung disease in children: interstitial lung disease, hypersensitivity lung disease and non-cardiogenic pulmonary oedema. The diagnosis is a diagnosis of exclusion and rests on a group of clinical arguments and also on the progress of the disease. Broncho-alveolar lavage rules out infectious disease. Respiratory function tests show non-specific anomalies. A lung biopsy may be indicated. The mechanism of the pulmonary toxicity are associated with disequilibrium of the oxidant/antioxidant and protease/antiprotease system as well as disturbance of the immune response or alteration of the pulmonary matrix by disease of the collagen system. Increased toxicity may be seen in children because of a very significant cumulative dose. The cytotoxic drugs which are most often implicated in causing this are bleomycin, methotrexate, cyclophosphamide and busulfan. Other drugs which are responsible for toxic lung disease are nitrofurantoin, sulfasalazine, D-penicillamine, betalactams, Diphenyl-hydantoin and carbamazepine. Acute post-radiation lung disease is rare. Post-radiation fibrosis is found six months after irradiation and hinders thoraco-pulmonary growth in the child. It is important to assess lung function in all children before any chemotherapy or thoracic irradiation. Cytotoxic drugs are the most common cause of toxic lung disease. This iatrogenic disease requires a multi-discipline approach to ensure the quality of care for these children.

We report two cases of nephrotic syndrome with minimal glomerular change complicating alpha-interferon therapy.

It has been recently reported that a number of anticancer drugs, including cisplatin, may exert their toxicity by inducing apoptosis. In order to investigate whether an alteration in the mechanisms involved in the process of apoptosis could contribute to cellular resistance, induction of apoptosis was studied in a cisplatin-resistant cell line (L1210/DDP) derived from a L1210 murine leukemia cell line (L1210/0). We first established that the mutant cell line resisted 5-azacytidine, a drug to which it was never exposed and which is known to have a very different mechanism of action from that of cisplatin. We then showed that these cells did not exhibit any DNA fragmentation or morphological changes typical of apoptosis, when exposed to toxic concentrations of either cisplatin or 5-azacytidine. The failure of these cells to undergo typical apoptosis upon cisplatin or 5-azacytidine exposure was correlated with the lack of a nuclear endonuclease activity present in wild type cell nuclei. However, staurosporine, a potent protein kinase C inhibitor, which exerted the same toxicity on both cell lines, induced the internucleosomal DNA fragmentation and morphological features of apoptosis in both of them. This indicates that a functional pathway for apoptosis is preserved in the resistant cells. The induction of this pathway can be correlated with the presence of a cytoplamic endonuclease activity whose specificity seems different from that operating in L1210/0 cells. In conclusion, our data indicate that the mechanisms which control activation of apoptosis in L1210/0 cells differ from those which operate in L1210/DDP cells. One of the differences concerns the nature and the subcellular localization of the endonuclease activity possibly involved in the internucleosomal DNA cleavage.

Etoposide is a major antineoplastic agent which was introduced in the clinic in the 1970s. Its clinical pharmacology was rediscovered at the end of the 1980s because optimal activity was demonstrated to be schedule dependent. The galenic adaptation of an oral form of the molecule led to more extensive studies investigating both the potential advantage of prolonged exposure to the drug and a better bioavailability at low doses. We reviewed current knowledge on clinical applications of continuous oral étoposide in various diseases and discussed the benefit of this mode of therapy over classical intravenous administration in terms of activity, cost and quality of life.

Every year in Canada, approximately one thousand cancer cases are reported in children from birth to age 14. Leukemia accounts for approximately 30 per cent of these cases. Leukemia and its treatment are likely to cause to children more oral complications than all other types of cancer. Both the leukemic condition itself and the therapy cause oral signs and symptoms with significant morbidity. Since life expectancy for a patient with leukemia has been greatly improved, dentists have an increasing role to play before, during and after a treatment against leukemia. A review of the oral manifestations related to leukemia and its treatment is presented.

Dihydropyrimidine dehydrogenase (DPD) is the principal enzyme involved in the catabolism of 5 fluorouracil (5 FU). The clinical importance of DPD has recently been demonstrated wit the identification of rare cases presenting a severe toxicity to 5 FU related to proven DPD deficiency. We report a new case in a patient with concurrent congenital osteogenesis imperfecta. We were surprised to find another similar association reported by Lyss. It is tempting to speculate that DPD activity may be abnormally regulated in osteogenesis imperfecta patients.

The establishment of relationships between pharmacokinetics and pharmacodynamics of anticancer drugs might allow to individualize the dosing of these drugs. Our knowledge of this kind of relationship has grown markedly in recent years. After a review of the different causes of variability in pharmacokinetics and pharmacodynamics of these drugs, the different models used for establishing these correlations were analyzed and criticized. Finally, the three methods for adapting drug dosing based on pharmacokinetic data were proposed and the main applications of these concepts were reviewed.

Catharanthus alkaloids are antitumoral drugs widely used in the treatment of malignant diseases. This review summarizes different aspects of their pharmacology (mechanism of action, resistance, clinical pharmacokinetics) as well as information on their uses in the clinical setting.

Administration of intravesical chemotherapy by mitomycin C (MMC) is an adjuvant treatment of the recurrent superficial bladder cancer. Since use of MMC in 1967, many different toxicities were reported. Those are local toxicities. Systemic toxicity is rare. At the hand of 2 cases reports and recent literature, we discuss the possible complications of intravesical therapy with MMC.