Modulation of BUdR labeling index in rat brain tumors following intracarotid ACNU administration

Summary Chloroethy1nitrosourea (CENU) chemotherapy has yielded limited benefit on survival of malignant brain tumors. Intracarotid administration of CENU is expected to have the advantage of increasing drug concentration reaching tumors. To understand basic knowledge of intracarotid chemotherapy, we monitor changes of proliferating rate after intracarotid injection of 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2chloroethyl)-3-nitrosourea hydrochloride (ACNU), using a bromodeoxyuridine (BUdR) labeling index (LI) in transplanted brain tumors of three cell strains.C6-2 tumor cells were in vitro sensitive to ACNU, and C6-2/ACNU and C6-1 cells were resistant. The drug sensitivity to ACNU was as follows: 11.9 tM in the C6-2 cells, 46.0 M in the C6-2/ACNU cells, and 49.7 M in the C6-1 cells at SD10, which gives 10% survival of clonogenic cells. The intracarotid ACNU at a dose of 30 mg/kg abruptly decreased the LI to 11% (mean) from 36% in C6-2 transplanted tumors. The LI remained low between 12 and 48 hours after, and then increased to the pretreatment level by 96 hours. In contrast, the LI of C6-1 tumors transiently fell to 15% from 42% at 12 hours after the injection, and subsequently increased to 36% at 24 hours and 37% at 48 hours.These results indicate that intracarotid ACNU administration shortly suppresses proliferating activity of tumors and that combined and alternating chemotherapy are mandatory for enhancing effectiveness of brain tumor chemotherapy.     

恶性胶质瘤同步放射化学治疗继以动脉灌注嘧啶亚硝脲治疗观察

１９８７年１１月至１９９１年２月对５５例手术后恶性胶质瘤（星形细胞瘤Ⅲ级或Ⅳ级）患者分成三组继续治疗：Ａ组（１４例）行同步放射化学治疗，随后每隔３～６个月行患侧动脉灌注嘧啶亚硝脲（ＡＣＮＵ）治疗；Ｂ组（１６例）单纯行同步放射化学治疗；Ｃ组（２５例）单纯放射治疗以作对照。近期效果用ＣＴ扫描比较，同步放射化学治疗的有效率（６３％）高于单纯放射治疗（２８％）Ｐ值＜０．０１。５５例患者均行连续随访，１、２、３年生存率Ａ组（９３％，６２％，５０％）明显高于Ｃ组（５１％，１３％，１３％），Ｐ值＜０．００１。Ｂ组１，２年生存率高于Ｃ组，但无统计学差别。作者认为采用同步放射化学治疗继以动脉灌注ＡＣＮＵ维持治疗对恶性胶质瘤术后患者是一个较佳的选择治疗方案。     

Phase II study of concurrent chemoradiotherapy with use of uneven fractionation for the treatment of glioblastoma

Background A phase II one-arm study was performed to evaluate the efficacy and safety of concurrent chemoradiotherapy with the use of uneven fractionation in glioblastoma patients. Methods A total of 19 glioblastoma patients underwent concurrent chemoradiotherapy with the use of uneven fractionation. Vincristine (VCR) and 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-1-nitrosourea hydrochloride (ACNU) were administered on day 1 and day 2, respectively. Irradiation at a dose of 3 Gy was administered on days 3 and 4, and at a dose of 1.5 Gy from day 5 on. The treatment was repeated at 10 day intervals. The total radiation dose was 57 Gy. Results All 19 patients received full dose irradiation. However, 8 patients required treatment interruption, and 2 patients required decreases in drug dosages due to the effects of acute toxicity such as, myelosuppression, liver function disorder and skin toxicity. The treatment responses were recorded as CR in 5, PR in 1, and NC in 10 patients. The remaining three patients received total removal of the enhancing area on CT or MRI. The 1 year and 2 year survival rates were 73% and 23%, respectively. The median survival times of this study and the historical controls were 16 months and 15 months, respectively. Conclusion The concurrent chemoradiotherapy failed to prolong the survival of glioblastoma patients.     

A phase II study of radiotherapy after hyperbaric oxygenation combined with interferon-beta and nimustine hydrochloride to treat supratentorial malignant gliomas

Hypoxic cells play a key role in the radioresistance of malignant glioma. Interferon-beta, ACNU as nimustine hydrochloride and radiotherapy (IAR) is a common therapy for malignant glioma in Japan. Since hyperbaric oxygenation (HBO) increases oxygen pressure in glioma tissue, we applied a modified IAR therapy, radiotherapy after HBO combined with interferon-beta and ACNU (HBO/IAR therapy), for supratentorial malignant gliomas. Daily radiation therapy was completed within 15min after HBO. We assessed HBO/IAR with respect to toxicity, response rates and the time of tumor progression (TTP). We also examined the incidence of responses by some prognostic factors before HBO/IAR, namely, age, Karnofsky performance scale (KPS), histological type, tumor size, tumor site and operation type. Of 39 patients who participated in this study, 35 underwent a complete schedule of HBO/IAR therapy in which toxicity was permissible. Thirty patients (76.9%) either maintained or increased KPS during HBO/IAR with a mean duration of 68±14 days. The response rates (CR+PR%) for glioblastoma, anaplastic astrocytoma and overall were 50%, 30% and 43%, respectively. The incidence of therapeutic responses among all prognostic factors before HBO/IAR did not significantly differ. Median TTP for patients with glioblastoma, patients with anaplastic astrocytoma, and overall were 38, 56 and 43 weeks, respectively. The present study suggested that HBO/IAR therapy could be applied to especially patients with poor prognostic factors, because of its short treatment period, its permissible toxicity and identical response to patients with good prognostic factors.     

ACNU, MTX And 5-FU Penetration of Rat Brain Tissue and Tumors

The distribution of radio-labeled ACNU, MTX and 5-FU in brain and tumor tissue was studied in female Wistar rats by macroautoradiography after intrathecal administration. In normal rats, ACNU and 5-FU, administered intracisternally, distributed rapidly in the subarachnoid space, ventricular system and cerebrospinal fluid (CSF). 5-FU and MTX penetrated the brain deeply; the diffusional transport of ACNU was limited to a depth of 1 or 2mm from the CSF surface of the brain. MTX and 5-FU clearance into the blood circulation was rather slow while ACNU cleared relatively quickly. The half time of ACNU, 5-FU and MTX radioactivity at the ventricular surface was 10, 21, and 110min, respectively, at their maximal concentration after intracisternal administration. In rats with leptomeningeal tumor induced by intracisternal inoculation of Walker 256 cells, the distribution patterns of ACNU, 5-FU, and MTX were essentially the same as in normal rats despite 10–20 cell layers of tumor growing in the subarachnoid space. 5-FU and MTX were able to penetrate tumor masses in the subarachnoid space; MTX penetration was slower than that of 5-FU and ACNU failed to penetrate to more than a depth of 1 or 2mm from the tumor surface.     

Antiproliferative effect of hyperthermia and ACNU on cultured human malignant melanoma cells

Human malignant melanoma cultured cells were treated either with ACNU (1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chlorethyl)-3-nitro sourea hydrochloride), hyperthermia, or the combination of ACNU and hyperthermia. The combination treatment inhibited the cell growth to a slightly synergistic degree compared to the respective single treatments. The present in vitro experimental results support in part the finding of our previous report that the combination treatment with ACNU and hyperthermia have a significantly synergistic antitumor effect to human melanoma transplanted to nude mice. However, the synergistic effect was much less intense in the present in vitro experiment. The difference may have resulted from the environmental differences between in vitro and in vivo experimental systems.     

Primary CNS lymphoma treated with combined intra-arterial ACNU and radiotherapy

Summary Object. To assess whether nimustine (ACNU), a drug that can cross the blood brain barrier, combined with radiotherapy, improved the survival of patients with primary central nervous system lymphoma (PCNSL). Clinical materials and methods. Between 1995 and 2005, we treated 63 immunocompetent PCNSL patients with combination therapy consisting of intra-arterial ACNU (100 mg/m²) and whole brain radiotherapy (36–50 Gy). Their median age was 60 years (range 28–81). The median follow-up was 24 months. Findings. With this regimen we achieved a complete response rate of 75% (43 of 57 patients). Kaplan–Meier estimates for median progression-free survival and median overall survival were 26 and 39 months, respectively. The 3- and 5-year survival rates were 51% (95% confidence interval [CI], 36–65%) and 32% (95% CI, 17–47%), respectively. By multivariate analysis, age (<60 vs. ≥60 years) was the only statistically significant prognostic factor; the WBRT dose, sex, and number of tumors were not significant prognostic factors in this study. Myelosuppression was the most frequent side effect, 60% of patients experienced grade 3–4 leukopenia. Late neurotoxicity as a result of treatment was observed in 14 of 43 patients (34%) and higher age (>60) was associated with a high risk of neurotoxicity. Conclusion. The intra-arterial administration of ACNU combined with radiation therapy yielded a high response rate at acceptable toxicity levels in younger patients with PCNSL. However, late neurotoxicity was a serious complication in patients above 60 years of age.     

ACNU和三尖杉酯碱分别联合MTX超选择性脑动脉灌注治疗恶性脑瘤的疗效比较

比较超选择性脑动脉灌注嘧啶亚硝脲（ＡＣＮＵ）加氨甲喋呤（ＭＴＸ）（Ａ组）以及三尖杉酯碱加ＭＴＸ（Ｂ组）治疗恶性脑胶质细胞瘤的疗效。方法将ＡＣＮＵ２～３ｍｇ／ｋｇ，三尖杉酯碱０１～０５ｍｇ／ｋｇ，ＭＴＸ０１～０２ｍｇ／ｋｇ按Ａ、Ｂ两组各１２例方案，采用超选择性脑动脉联合灌注化疗，并于化疗后１～１５个月以ＣＴ检查评定疗效。结果Ａ组肿瘤体积缩小４８３２％，Ｂ组缩小４６２１％；Ａ组有效者占４／１２，Ｂ组占３／１２；平均生存期分别为２５３个月和２３３个月；两组治疗前后肿瘤体积变化均有显著性差异，但两组疗效则无明显差异；并均无眼部及严重脑部并发症。结论ＡＣＮＵ加ＭＴＸ以及三尖杉酯碱加ＭＴＸ超选择性脑动脉灌注对恶性脑胶质细胞瘤的疗效相似，毒副作用小。     

恶性胶质瘤施行嘧啶亚硝脲化学治疗临床观察

目的：针对恶性星形细胞瘤手术后残留的肿瘤组织，用化学药物方法将其消灭和抑制生长，延长病人的生存期和改善生存质量。方法：将手术后的恶性星形细胞瘤病人施行动脉超选择灌注和静脉输液法。每日一次，２～３ｍｇ／ｋｇ。结果：１８例病人术后一年观察，未见肿瘤生长８例占４４％，不同程度复发８例占４４％，死亡２例。结论：恶性星形细胞瘤术后辅以化学药物治疗，将抑制肿瘤生长。     

Importance of antitumor immunity for complete cure of highly drug-sensitive leukemia in mice

Summary Seven transplantable leukemia lines were established from spontaneous leukemias and screened for 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(chloroethyl)-1-nitrosourea hydrochloride (ACNU) sensitivity in DDD mice. Three of them were classified as highly sensitive, two as sensitive and two as resistant to ACNU. A highly sensitive line, DL812, was extensively characterized from a therapeutic point of view. DL812 cells were so invasive as to produced enlargement of spleens and lymph nodes but not local tumors when injected s.c., markedly sensitive to in vitro ACNU exposure and modrately immunogenic. The invasion process of DL812 cells differed with the status of host immunity. Advanced DL812 leukemias were macroscopically completely cured with normalization of spleen and lymph node sizes 3–7 days after an i.p. injection of 0.5 mg ACNU, but more ACNU-resistant leukemias with splenomegaly and enlarged lymph nodes recurred thereafter. Recurring DL812 cells were approximately four times more resistant to in vitro ACNU exposure but maintained similar immunogenicity as compared to the original ones. Permanent cures of advanced leukemias were achieved by ACNU treatment plus subsequent adoptive transfer of immune splenocytes in 15% of diseased mice. The results suggest the importance of host antitumor immunity for permanent cures of highly drug-sensitive leukemias, overcoming drug resistance and relapse.Abbreviations ACNU 3-[(4-amino-2-methyl-5-pyrimidinyl)-methyl[-1-(2-chloroethyl)-1-nitrosourea hydrochloride - FITC fluorescein-isothiocyanate-conjugated - Ig immunoglobulin - M199 medium 199 - PBS phosphate-buffered saline solution This work was supported in part by a grant-in-aid for cancer research from the Ministry of Education, Science and Culture, Japan