Potential central nervous system antitumor agents. Aziridinylbenzoquinones. 1

A series of 3,6-substituted 2,5-diaziridinyl-1,4-benzoquinones was prepared as potential CNS antitumor agents. Activity was evaluated in the murine leukemia L1210 system. The diurethane derivative 9 was found to have significant activity in that system as well as in the intraperitoneal P388 and B16 tumor models. Marginal Lewis lung activity was observed. Reproducible activity was seen in the intracerebral L1210 and P388 systems. Multiple cures were observed in the murine ependymoblastoma brain tumor model. The effect of substituent type on aziridinylquinone activity is discussed.

Assessment of bone marrow function: microscopy versus the agar colony assay

Changes in bone marrow status followig cytotoxic chemotherapy were measured by means of peripheral blood counts, bone marrow cytology and colony-formation in agar culture. A correlation is described between colony-forming ability and marrow differential count.

[Role of chemotherapy in long-term survival of malignant glioma (author's transl)]

Effect of chemotherapy was evaluated from the view point of postoperative survival rate in 102 consecutive cases of histologically verified glioblastomas treated during past 16 years. As a result of the study, the "additive effect" of chemotherapy on the ordinary surgical operation and radiation therapy could not be clarified. However, the effect of chemotherapy was worth to note among 6 cases which survived more than 5 years after operation. Then, combination of various treatment including chemotherapy should be repeatedly applied in individual cases of glioblastoma.

[Combined radiotherapy and chemotherapy of the central nervous system in malignant neoplasms of children (author's transl)]

A combination of radiotherapy and cytostatic drugs was used in the treatment of 39 children with primary brain tumour between 1961 and 1974, and 40 children with acute lymphoid leukaemia between 1971 and 1974. Best results were obtained with medulloblastoma using cerebrospinal radiotherapy and cytostatic drugs: 10 of 17 children are still alive. Of 40 children with acute lymphoid leukaemia 18 are still alive after cerebrospinal or cranial radiotherapy. The side effects of the combined therapy were within justifiable limits.

Long-term survival of patients treated with BCNU for brain tumors

The authors present three patients who, after excision and irradiation of their brain tumors, were treated with BCNU for recurrence. All three patients responded well and now are without evidence of tumor, 37, 30, and 36 months after BCNU was stopped. Although these patients represent only a small fraction of those treated with BCNU, they indicate the potential role of chemotherapy in the management of glial tumors.

Potential central nervous system antitumor agents. Hydantoin derivatives

Hydantoin derivatives of varying lipophilic character were prepared as nitrogen mustard carriers for CNS antitumor evaluation. Activity was studied in the murine ependymoblastoma brain tumor system. Multiple cures were observed for three of the four analogs examined. The compounds were also active in the intraperitoneal leukemia L1210 and P388 systems as well as in B16 melanoma and Lewis lung carcinoma.

Pattern recognitiion and structure-activity relationship studies. Computer-assisted prediction of antitumor activity in structurally diverse drugs in an experimental mouse brain tumor system

This paper reports the application of pattern recognition and substructural analysis to the problem of predicting the antineoplastic activity of 24 test compounds in an experimental mouse brain tumor system based on 138 structurally diverse compounds tested in this tumor system. The molecules were represented by three types of substructural fragments, the augmented atom, the heteropath, and the ring fragments. Of the two pattern recognition methods used to predict the activity of the test compounds the nearest neighbor method predicted 83% correctly while the learning machine method predicted 92% correctly. The test structures and the important substructural fragments used in this study are given and the implications of these results are discussed.

Chemotherapy of primary malignant brain tumors in children

Numerous investigators have reported on a variety of chemotherapeutic agents tested in children suffering from recurrent medulloblastoma, brain stem glioma, and ependymoma, in efforts to improve survival and reduce morbidity. Evaluation of such studies is difficult, because there were rarely more than three or four cases of each tumor type. In medulloblastoma, 5-year survival averages 32%; recurrence follows initial therapy by months to years. The recurrence may be intracranial, spinal, or metastatic, making comparison among cases very difficult. Intrathecal methotrexate (MTX) has been successfully used to treat medulloblastoma, with responses reported in about three-fourths of the cases. Intraventricular MTX is lethal when ventricular obstruction is present. MTX has been less useful in therapy of brain stem glioma and ependymoma. BCNU and CCNU have produced responses in patients with ependymoma, medulloblastoma, and brain stem glioma. Vincristine, alone or in combination, has been useful primarily in medulloblastomas. Less experience is available with several newer methods of chemotherapy, but promising results have been reported with procarbazine, 4'-demethyl-epipodophyllotoxin-beta-D-thenylidine-glucosede (PTG, VM 26), and high dose intravenous methotrexate with citrovorum rescue. It is likely that only a nationwide cooperative effort will achieve significant improvement in the chemotherapy of malignant brain tumors in children.

Procarbazine hydrochloride in the treatment of brain tumors. Phase 2 study

✓ A series of 43 patients, all of whom were deteriorating due to progression of primary or metastatic brain tumors, were treated daily with n-isopropyl-α-(2-methylhydrazine)-p-toluamide hydrochloride (matulane, Procarbazine hydrochloride: NSC-77213, 150 mg./m2) for 30 consecutive days, with a 30-day rest interval between treatments. Of 29 patients evaluated, 12 showed a definite clinical response to therapy and two a probable response, for a response rate of 48%. Reversible myelosuppression was the major toxic effect encountered. Combination with other chemotherapeutic agents may enhance the drug's effectiveness against brain tumors.

The development of an intracerebral glioma model for brain tumor chemotherapy

✓ The authors describe a brain tumor model for chemotherapy studies. The tumor is an intracerebral ependymoblastoma that kills the host in a short time (median survival, 27.5 days) and yields consistent, uniform survival curves. A suspension of tumor cells is injected into the right frontal lobe of the mouse by means of a stereotaxic frame, and produces a highly invasive, almost entirely intracranial brain tumor. The use of mice permits extensive chemotherapeutic trials for brain tumors at low cost. It is felt that this model will prove to be very useful for studies of brain tumor chemotherapy.

Chloroethyl-cyclohexyl-nitrosourea (CCNU) in the treatment of malignant brain tumors

✓ Oral 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), a lipid-soluble non-ionized chemotherapeutic agent, was used in the treatment of 26 patients with malignant brain tumor, primarily glioblastoma. Most patients had first received conventional surgery, and about one half had received x-ray therapy. Over 1½ years, 113 courses of CCNU (130–150 mg/m2) were given and analyzed for clinical results and agent toxicity. A new central nervous system (CNS) disease staging system was used to measure patient impairment and therapeutic response. Thirty-seven per cent of all symptomatic patients had significant remission of clinical disease, lasting a median of 5 months. Data are presented implying that the treatment of asymptomatic patients may also be of considerable value. The most significant toxicity was delayed reversible thrombocytopenia, which was less severe than that seen with nitrosourea BCNU. Despite the cumulative toxicity observed with all three bone-marrow elements, serious complications were rare. Our initial experience indicates that CCNU is an effective agent for the treatment of malignant brain tumor and that the CNS disease staging system is useful in obtaining quantitative results.

Chemotherapy of brain tumors. Uptake of tritiated methotrexate by a transplantable intracerebral ependymoblastoma in mice

✓ The uptake and distribution in brain tumors of a parenterally administered chemotherapeutic agent were studied in mice bearing intracerebral implants of a transplantable ependymoblastoma. Tritiated methotrexate (3H-MTX) was injected intravenously, and autoradiographs of the tumors and adjacent brain were prepared at 2, 10, and 60 min after injection using a technique suitable for soluble compounds. In the tumors at 2 min the drug was mainly intravascular and interstitial while at 60 min the drug was mainly intracellular. This is the first demonstration of cellular uptake of a chemotherapeutic agent by neoplastic cells within the brain. At 60 min, almost all the cells in the central mass of the intracerebral tumors were heavily labeled. However, cells at the periphery of the mass and those infiltrating into adjacent brain showed scanty labeling. Uptake in normal brain was very low, while uptake in edematous brain adjacent to the tumors was much higher although not as high as in the tumors. The study shows that this chemotherapeutic agent is capable of penetrating into the neoplastic cells of an intracerebral tumor following parenteral administration, but that the degree of penetration varies considerably depending on the location of the cells within the brain.