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In the last few years tremendous progress has been made in the treatment of acute myelogenous leukemia: remissions have been observed more frequently and they last longer. Present-day therapy is described. It has become so complex that induction therapy must be carried out by oncologic departments. Maintenance treatment can however be conducted by the family physician, acting in close cooperation with the oncology unit.
The contributions of defective mismatch repair (MMR) and the p53-response to cell killing by N-(2-chloroethyl)-N'-cyclohexyl-N-nitrosourea (CCNU) were evaluated. MMR defects were previously shown to be associated with CCNU sensitivity (G. Aquilina et al., Cancer Res., 58: 135-141, 1998). Unexpectedly, eight MMR-deficient variants of the A2780 human ovarian carcinoma cell line were 3-fold more resistant to CCNU than the MMR-proficient parental cells. The variants were members of a preexisting subpopulation of drug-resistant A2780 cells. In addition to deficient expression of the MMR protein hMLH1, an essential component of the hMutL alpha repair complex, the variants exhibited alterations in the expression of other genes that influence drug sensitivity. Although A2780 cells possess a wild-type p53 gene, all of the clones contained a heterozygous G to T tranversion at codon 172. This change resulted in a Val to Phe substitution and was associated with a constitutive production of high levels of p53, which was inactive as a transcriptional activator of bax and p21. The hMLH1/p53 defective variants displayed a less prominent cell cycle arrest and reduced apoptosis after CCNU treatment. In contrast, MMR-defective A2780 variants, which had a similar hMutL alpha defect but retained a wild-type p53, did exhibit the expected CCNU sensitivity. Expression of a dominant-negative p53val135 increased CCNU resistance of both MMR-proficient and MMR-deficient A2780 cells. Thus, defective MMR and p53 influence CCNU sensitivity in opposite directions. Their effects are independent, and sensitization by defective MMR does not require a functional p53 response.
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The modulating effect of newly synthesized alkylating spin labeled triazene and spin labeled nitrosourea derivatives on the DOPA-oxidase activity of mushroom tyrosinase has been investigated by Bumett's spectrophotometric method (Burnett et al., 1967). All spin labeled triazenes have exhibited activating effect on DOPA-oxidase activity of tyrosinase, whereas clinically used triazene (DTIC), which does not contain nitroxide moiety, have showed inhibiting effect. At the same experimental conditions the spin labeled aminoacid nitrosoureas have showed dual effect - activating, in the beginning of the enzyme reaction and inhibiting later on. It is deduced that the activating effect of the spin labeled compounds is due to the nitroxide moiety and the inhibiting effect of all compounds depends on their half-life time. This study might contribute to make more clear the mechanism of action of the new compounds and on the other hand would come in quite useful as a preliminary prognosis for their antimelanomic activity.
Oligodendroglioma (ODG) constitute a specific type of gliomas, with a better prognosis than astrocytic tumours of similar grade. No clear criteria exist to differentiate astrocytoma from ODG, leading to a significant inter-observer variation in the diagnosis of ODG. ODG are genetically characterised by chromosomal lesions in the 1p36 and the 19q13.3 regions. ODG tumours without these lesions but with TP53 lesions or glioblastoma multiforme-like genetic lesions (loss of chromosome 10 and amplification of 7p) probably constitute a different entity with an oligodendroglial phenotype. Recent clinical trials have shown that ODG are sensitive to chemotherapy with 60-65% of patients responding, with a median response duration of 1-1.5 years. This holds for both low and high-grade ODG; the response rate in mixed oligoastrocytomas may be slightly less but is still better than that of pure astrocytic tumours. There is a strong correlation between a favourable response to chemotherapy and the presence of 1p36 and 19q13.3 lesions, suggesting this may be used to select patients for treatment. The presence of 1p lesions is also related to a longer progression free survival after radiation therapy, implicating that the assessment of the presence of 1p lesions is an important prognostic tool for ODG. The chemosensitivity of ODG is not limited to the PCV schedule. Ongoing trials are investigating whether adjuvant chemotherapy after surgery and radiation therapy provides better survival and quality of life in newly-diagnosed anaplastic ODG. However, even patients with a good response to chemotherapy will ultimately relapse. This calls for improvement of the chemotherapy schedules and for improvement of second line chemotherapy. In the near future molecular analysis may become an important tool to identify tumours that are likely to respond to chemotherapy.
Drug resistance of non-Hodgkin's lymphomas may involve mechanisms of the multidrug resistance phenotype including the lung resistance protein (LRP) and the multidrug resistance protein (MRP1). To determine the clinical relevance of these multidrug resistance factors in previously untreated diffuse large B-cell lymphomas (n = 48), we studied LRP and MRP1 expression in lymphoma cells and their impact on clinical outcome. LRP and MRP1 expression were immunohistochemically assessed by means of the monoclonal antibodies LRP-56 and MRPr1, respectively. LRP was positive in 23% and MRP1 in 44% of the samples. LRP expression was associated with higher tumor stage (P = 0.03), elevated serum lactate dehydrogenase levels (P = 0.01), and the International Prognostic Index (P = 0.0001). LRP-positive patients had a lower complete response rate to polychemotherapy than LRP-negative patients (18 versus 65%; P = 0.006). Patients with LRP expression had a shorter overall survival than those without LRP expression (median of 0.9 years versus median not reached; P = 0.001). MRP1 expression was independent of clinical and laboratory parameters and had no impact on the outcome of chemotherapy or survival of the patients. These data suggest that LRP expression but not MRP1 expression is an important mechanism of drug resistance associated with worse clinical outcome in previously untreated diffuse large B-cell lymphomas. Thus, the reversal of LRP-mediated drug resistance may improve clinical outcome in diffuse large B-cell lymphoma in the future.
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Although the efficacy of the nitrosourea-based combination chemotherapy procarbazine, N-(2-chloroethyl)-N'-cyclohexyl-N-nitrosurea, and vincristine (PCV) has been previously demonstrated in the setting of anaplastic/intermediate-grade gliomas, the benefit for glioblastoma patients remains unproven. In the current study, we sought to determine whether the addition of alpha-difluoromethylornithine (eflornithine), an inhibitor of ornithine decarboxylase, which has shown encouraging results in the setting of recurrent glioma patients, to a nitrosourea-based therapy (PCV) would constitute a more effective adjuvant therapy in the treatment of glioblastoma multiforme patients in the postradiation therapy setting. Following conventional radiation therapy, 272 glioblastoma (GBM) patients were randomized to receive either alpha-difluoromethylornithine-PCV (DFMO-PCV; 134 patients) or PCV alone (138 patients), with survival and time to tumor progression being the primary endpoints. The starting dosage of DFMO was 3.0 g/m2 p.o. q8h for 14 days before and after treatment with N-(2-chloroethyl)-N-cyclohexyl-N-nitrosurea; PCV was administered as previously described1. Clinical and radiological (Gadolinium-enhanced MRI) follow-ups were nominally at the end of each 6 or 8 week cycle (PCV at 6 weeks; DFMO-PCV at 8 weeks). Laboratory evaluations for hematologic and other adverse effects were at 2 week intervals. There was no difference in median survival or median time-to-tumor progression between the two treatment groups, as measured from day of commencement of postradiotherapy chemotherapy [MS (months): DFMO-PCV, 10.5; Overall survival, as measured from time of tumor diagnosis at first surgery, was 13.3 and 14.2 months at the median and 6.2 and 8.7% at 5 years, respectively, for the DFMO-PCV and PCV arms. The treatment effect was unchanged after adjustment for age, performance status (KPS), extent of surgery, and other factors using the multivariate Cox proportional hazard model. Adverse effects associated with DFMO consisted of gastrointestinal (diarrhea nausea/vomiting), cytopenias, and minimal ototoxicity (limited to tinnitus) at the dose range tested. The addition of DFMO to the nitrosourea-based PCV regimen in this phase III study demonstrated no additional benefit in glioblastoma patients, underscoring the resistance of glioblastoma multiforme tumors to alkylating agents. For patients with anaplastic (intermediate grade) gliomas, in which the previously demonstrated benefit of post-radiation chemotherapy is more substantial, the evaluation of DFMO-PCV vs. PCV is still ongoing and hopefully will yield more encouraging results.
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The overall cure rate of locally advanced non-small cell lung carcinoma (NSCLC) remains poor. Although there have been encouraging reports of preoperative use of chemotherapy, more recent trend is the trimodal approach of radiation, chemo, and surgical-therapies. With the trimodal therapy, increased tumor response and resectability are reported, however, there are increased treatment related side effects. We observed that a relatively small dose of radiation given prior to induction chemotherapy greatly enhanced the tumor response to the chemotherapy without increased toxicity. A total of 18 patients (8 IIIA and 10 IIIB) were initially given 20 Gy of radiation therapy in 10 fractions and then received 2 courses of Taxol combination chemotherapy. The overall response rate was 83% (15/18) and 13 out of 18 patients underwent surgery. There was one postoperative death (not therapy related). It is speculated that the small dose of radiation therapy may have sensitized the tumor to subsequent chemotherapy, and we suggest a new hypothesis of "Radiation therapy induced chemotherapy sensitization".
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A water-soluble nitrosourea, 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-1-nitrosourea hydrochloride (ACNU), was tested for antitumor activity against lymphoid leukemia L-1210 in BDF1 mice. The results obtained were as follows: (1) ip--ip system: By daily administrations optimal dose for 12 days, MED (ILS40), and therapeutic ratio were found to be 18 mg/kg, 1.3 mg/kg, and 14, respectively, and by a single injection, those were found to be 46 mg/kg, 4.2 mg/kg, and 11, respectively. The therapeutic ratio of ACNU was the highest of all the drugs tested. At the neighboring dose level to optimal dose most of leukemic mice survived more than 60 days. (2) ip--iv system: Remarkable prolongation of life-span was observed by a single injection. Majority of mice administered more than 32 mg/kg of ACNU survived more than 60 days. (3) ip--po system: Remarkable prolongation of life-span was shown by a single administration and most of leukemic mice given more than 46 mg/kg of ACNU survived over 60 days. (4) iv--ip system: By a single administration of ACNU remarkable prolongation of life-span was seen and majority of leukemic mice were rescused at doses of 32 mg/kg or more. (5) iv--iv system: Result almost similar to iv--ip system was obtained. (6) iv--po system: The result in this system was similar to that in ip--po system. Thus, the compound was highly effective in leukemic mice by either its parenteral or oral administration.
Formulation of a sterile preparation for the parenteral administration of a water insoluble drug is described. Methyl CCNU was first dissolved in absolute alcohol and slowly added to a fat emulsion, Intralipid. The preparation was found to be stable for eight hours at room temperature and seven days under refrigeration. After administration of the preparation to approximately 100 patients, no significant side effects were attributed to the fat emulsion.
The effects of single agent therapy with 1-(-chloroethyl)-3-cyclohexyl-1-nitrosourea, 5-fluorouracil, and 5-(3,3-dimethyl-1-triazeno)-imidazole-4-carboxamide on a human malignant melanoma transplanted and passed serially in thymusless nude mouse were studied. Tumor response varied. A single dose of 1-(-chloroethyl)-3-cyclohexyl-1-nitrosourea induced initial tumor regression, but thereafter growth resumed at a rate similar to that in the untreated control animals. Wehn 1-(-chloroethyl)-3-cyclohexyl-1-nitrosourea was given in divided dosage at an interval of 8 days, marked and persistent tumor regression was observed. 5-Fluorouracil had no effect. Treatment with 5-(3,3 dimethyl-1-triazeno)-imidazole-4-carboxamide was always reflected by almost total regression of tumors, an effect that was independent of dose within the range tested in this study. The results resemble those reported from clinical practice in patients with disseminated malignant melanomas treated with the same agents. This suggests that the pattern of drug susceptibility is preserved after transplantation of tumors in the nude mouse. The human tumor-nude mouse system is advocated as a new in vivo model for determination of individual tumor response to chemotherapeutic agents, and its potential as a model for the proving of new chemotherapeutic agents is suggested.
OBJECTIVE: To study the efficacy of chemotherapy for glioblastoma on the basis of brain irradiation. METHODS: It was previously reported that the permeability of the blood brain barrier (BBB) to methotrexate could be increased by brain irradiation. In this study, glioblastoma patients were divided into 2 groups, 28 patients in each group. On group of patients was treated with CCNU or BCNU after having given 20-40 Gy irradiation to the brain. The other group of patients received radiation treatment alone. RESULTS: The 1-, 3-, and 5-year survival rate of the two groups of patients was 57.1%, 22.5%, 15.0% and 17.9%, 7.1%, 3.6%, respectively. The median survival time was 29.7 +/- 7.0 and 9.7 +/- 3.5 months, respectively (P < 0.001). CONCLUSION: Increase in permeability of the BBB after 20-40 Gy brain irradiation may provide an optimal chance for intracranial chemotherapy of glioblastoma.
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A comparison has been made of the effects of three nitrosoureas (BCNU, CCNU, and methyl-CCNU) on the cells of Lewis lung carcinoma and B16 melanoma in vivo using a new in vitro method for assaying colony-forming cells. In addition, the effect on early hemopoietic precursors has been studied using the in vivo spleen colony assay and the in vitro agar colony assay. The results show that the three nitrosoureas are selective against Lewis lung carcinoma and B16 melanoma relative to normal hemopoietic precursors. Furthermore, the effect of these nitrosoureas is unchanged when the rate of proliferation of the hemopoietic precursor cells is increased.
I) Malignant gliomas: Randomized clinical trials conducted in the USA showed that radiotherapy plus chemotherapy with nitrosoureas offered a long-term survival advantage to patients younger than 60 years old with malignant gliomas. Combination chemotherapy, such as procarbazine/CCNU/vincristine (PCV) must be tested further, and intra-arterial chemotherapy with nitrosoureas offered no survival advantage. Combination chemotherapy with PCV showed efficacy for patients with anaplastic oligodendroglioma and anaplastic oligoastrocytoma. II) Medulloblastoma: The addition of chemotherapy to radiotherapy improved the survival of patients with poor risk medulloblastoma, and may reduce the required craniospinal radiation dose in patients with good risk medulloblastoma. III) Primary CNS lymphoma (PCNSL): Combination of chemotherapy with high-dose MTX and radiotherapy improved survival of patients with PCNSL; however, the neurotoxicity produced by this treatment modality is a serious problem in older patients. IV) Intracranial germ cell tumors: The addition of chemotherapy to radiotherapy may produce long term survival with good quality of life in patients with germinoma. Neoadjuvant therapy consisting of chemotherapy and radiotherapy followed by complete surgical excision improved survival of patients with intracranial nongerminomatous germ cell tumors.