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PubMed2006

A phase I/II study of lomustine and temozolomide in patients with cerebral metastases from malignant melanoma.

Temozolomide is an alkylating agent with activity in the treatment of melanoma metastatic to the brain. Lomustine is a nitrosurea that crosses the blood brain barrier and there is evidence to suggest that temozolomide may reverse resistance to lomustine. A multicentre phase I/II study was conducted to assess the maximum-tolerated dose (MTD), safety and efficacy of the combination of temozolomide and lomustine in melanoma metastatic to the brain. Increasing doses of temozolomide and lomustine were administered in phase I of the study to determine the MTD. Patients were treated at the MTD in phase II of the study to six cycles, disease progression or unacceptable toxicity. Twenty-six patients were enrolled in the study. In phase I of the study, the MTD was defined as temozolomide 150 mg m(-2) days 1-5 every 28 days and lomustine 60 mg m(-2) on day 5 every 56 days. Dose-limiting neutropaenia and thrombocytopaenia were observed at higher doses. Twenty patients were treated at this dose in phase II of the study. No responses to therapy were observed. Median survival from starting chemotherapy was 2 months. The combination of temozolomide and lomustine in patients with brain metastases from melanoma does not demonstrate activity. The further evaluation of this combination therefore is not warranted.

Administration, Oral↗
PubMed1992

Influence of O6-methylguanine on DNA damage and cytotoxicity of temozolomide in L1210 mouse leukemia sensitive and resistant to chloroethylnitrosoureas.

Temozolomide is a new anticancer agent which in the early clinical investigation has shown promising antitumor activity. It decomposes spontaneously to the active metabolite of DTIC (MTIC). Temozolomide is more cytotoxic against L1210 than against a subline L1210/BCNU, resistant to chloroethylnitrosoureas. Using [methyl-3H] temozolomide we found that after 1 h exposure the amount of O6-methylguanine (O6mGua) was twice as high in L1210 than in L1210/BCNU whereas the amount of N7 mGua was approximately the same in the two cell lines. O6-alkylguanine DNA alkyltransferase (AT) levels were higher in L1210/BCNU than in L1210, supporting the view that the resistance to methyltriazenes is probably related to the efficient repair of O6mGua in L1210/BCNU. Exposure of L1210/BCNU cells to 0.4 mM O6mGua for 24 h resulted in a depletion of AT and in a higher temozolomide-induced cytotoxicity. In the sensitive cell line L1210, temozolomide activity was not potentiated by O6mGua pretreatment. Moreover, in L1210/BCNU, O6mGua increased DNA single-strand breaks caused by temozolomide, suggesting that O6-guanine alkylation induces an excision repair mechanism in cells depleted in AT.

Alkalies↗
PubMed1999

Sensitivity of short-term cultures derived from human malignant glioma to the anti-cancer drug temozolomide.

The activity of temozolomide, which has shown clinical activity against malignant glioma, has been assessed in vitro against short-term cultures derived from these tumors using an intermediate duration microtitration assay with MTT reduction as the end-point This assay has previously been shown to correlate closely with a monolayer clonogenic assay. Sensitivity was assessed in 15 short-term cultures (passage levels 3-9) derived from WHO grade III and IV astrocytomas. These cultures had a median ID50 value of 258 microM for temozolomide and 16.13 microM for CCNU. Maximum serum concentrations of temozolomide are of the order of 75 microM but only three of 15 (20%) cultures had ID50s below this value. Fourteen of 15 (93%) cultures displayed cross-resistance between temozolomide and CCNU, although one line which was extremely resistant to CCNU retained sensitivity to temozolomide. Comparative studies of published clonogenic survival curves indicate that the short-term glioma cell lines used in this study have similar sensitivities to established glioma cell lines, whilst colon carcinoma cell lines and bladder carcinoma are often more resistant to these drugs. Cell lines from testicular teratoma cell lines may show exquisite sensitivity to temozolomide and this level of sensitivity is seen only occasionally in short-term cultures derived from malignant glioma.

Adult↗
PubMed2002

Effect of temozolomide on central nervous system relapse in patients with advanced melanoma.

Temozolomide has shown efficacy in the treatment of metastatic melanoma similar to that of dacarbazine (DTIC), the standard chemotherapy, but with the added benefit of penetration into the central nervous system (CNS). Isolated CNS relapse is increasingly a problem for patients who respond to biochemotherapy. By replacing DTIC with temozolomide in treatment regimens, the incidence of CNS relapse might be reduced. This hypothesis is difficult to test in a prospective randomized controlled trial because of the large number of patients that would be required. We have examined this question in a retrospective case control study, observing the rates of CNS relapse in advanced metastatic melanoma patients responding to DTIC- or temozolomide-based chemotherapy in three institutions. Twenty-one DTIC and 20 temozolomide responders were identified, and have been followed up for a median of 19.0 months (range 6.0-74.3 months). CNS relapse occurred in nine DTIC- and two temozolomide-treated patients, a statistically significant difference in favour of the new agent (P = 0.03). These results support the investigation of temozolomide as a replacement for DTIC in systemic treatment regimens for melanoma.

Adult↗
PubMed2004

Transcriptional targeting of adenovirally delivered tumor necrosis factor alpha by temozolomide in experimental glioblastoma.

Temozolomide is an oral alkylating agent shown to have modest efficacy in the treatment of glioblastoma multiforme. Tumor necrosis factor alpha (TNF-alpha) is a polypeptide cytokine with synergistic antitumor activity in combination therapy with alkylating agents. We investigated the combined use of Ad.Egr-TNF, a replication-defective adenoviral vector encoding the cDNA for TNF-alpha under the control of chemo-inducible elements of the egr1 gene promoter, and intraperitoneal temozolomide in an intracranial human malignant glioma model. In hind limb U87MG xenografts, temozolomide produced a 6.4-fold greater induction of TNF-alpha after infection with Ad.Egr-TNF compared with Ad.Egr-TNF alone at 96 hours (P < 0.02). TNF-alpha and temozolomide combination leads to a synergistic decrease in U87 cell viability at 72 hours compared with either treatment alone (P < 0.001). Median survival for animals treated with Ad.Egr-TNF alone, temozolomide alone, and Ad.Egr-TNF/temozolomide was 21, 28, and 74 days, respectively (P < 0.001 by log-rank). Flow cytometric assessment of apoptosis revealed a synergistic increase in U87 cell apoptosis in vitro at 72 hours (P < 0.05), and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) evaluation of tumor sections revealed significantly increased TUNEL-positive cells after combination treatment compared with either treatment alone (P < 0.05). In conclusion, combination treatment with transcriptionally activated intratumoral TNF-alpha and systemic temozolomide significantly prolongs survival in an experimental glioblastoma multiforme model.

Adenoviruses, Human↗
PubMed2004

CpG island hypermethylation of the DNA repair enzyme methyltransferase predicts response to temozolomide in primary gliomas.

PURPOSE: The DNA repair enzyme O(6)-methylguanine DNA methyltransferase (MGMT) inhibits the killing of tumor cells by alkylating agents, and its loss in cancer cells is associated with hypermethylation of the MGMT CpG island. Thus, methylation of MGMT has been correlated with the clinical response to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) in primary gliomas. Here, we investigate whether the presence of MGMT methylation in gliomas is also a good predictor of response to another emergent alkylating agent, temozolomide. EXPERIMENTAL DESIGN: Using a methylation-specific PCR approach, we assessed the methylation status of the CpG island of MGMT in 92 glioma patients who received temozolomide as first-line chemotherapy or as treatment for relapses. RESULTS: Methylation of the MGMT promoter positively correlated with the clinical response in the glioma patients receiving temozolomide as first-line chemotherapy (n = 40). Eight of 12 patients with MGMT-methylated tumors (66.7%) had a partial or complete response, compared with 7 of 28 patients with unmethylated tumors (25.0%; P = 0.030). We also found a positive association between MGMT methylation and clinical response in those patients receiving BCNU (n = 35, P = 0.041) or procarbazine/1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (n = 17, P = 0.043) as first-line chemotherapy. Overall, if we analyze the clinical response of all of the first-line chemotherapy treatments with temozolomide, BCNU, and procarbazine/1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea as a group in relation to the MGMT methylation status, MGMT hypermethylation was strongly associated with the presence of partial or complete clinical response (P < 0.001). Finally, the MGMT methylation status determined in the initial glioma tumor did not correlate with the clinical response to temozolomide when this drug was administered as treatment for relapses (P = 0.729). CONCLUSIONS: MGMT methylation predicts the clinical response of primary gliomas to first-line chemotherapy with the alkylating agent temozolomide. These results may open up possibilities for more customized treatments of human brain tumors.

Adult↗
PubMed2002

Phase I study of temozolomide in relapsed/refractory acute leukemia.

PURPOSE: To determine the dose-limiting toxicity and maximum-tolerated dose of temozolomide in patients with acute leukemia. PATIENTS AND METHODS: Twenty patients (16 with acute myelogenous leukemia, two with acute lymphoblastic leukemia, and two with chronic myelogenous leukemia in blastic phase) received 43 cycles of temozolomide. Patients began treatment at two different dose levels: 200 mg/m(2)/d for 7 days or 200 mg/m(2)/d for 9 days. RESULTS: Prolonged aplasia was the dose-limiting toxicity, and the maximum-tolerated dose was 7 days of temozolomide. Overall treatment was well tolerated: hospitalization was required in only nine of 43 courses, and there were no treatment-related deaths. Two patients obtained a complete response, and two others met criteria for complete response except for platelet recovery. Overall, nine of 20 patients had a significant decrease in bone marrow blasts after temozolomide treatment. CONCLUSION: Temozolomide was well tolerated and had significant antileukemic activity when administered as a single agent. Further studies of temozolomide in hematologic malignancies are indicated.

Adult↗
PubMed2004

Temozolomide for the treatment of brain metastases associated with metastatic melanoma: a phase II study.

PURPOSE: Temozolomide is a well-tolerated oral alkylating agent with activity in the CNS. A multicenter, open-label, phase II study was conducted to assess the safety and efficacy of temozolomide in patients with brain metastases from metastatic melanoma (MM) who did not require immediate radiotherapy. PATIENTS AND METHODS: Eligible patients had histologically confirmed MM to the brain, and no prior radiotherapy or radiosurgery for brain metastases. Previously untreated patients received temozolomide at 200 mg/m(2)/d x 5 days; previously treated patients received 150 mg/m(2)/d x 5 days every 28 days. Treatment continued for 1 year or until disease progression or unacceptable toxicity. RESULTS: Of 151 patients enrolled, 117 had received no prior systemic chemotherapy, and 34 had received prior chemotherapy for MM. Among previously untreated patients, 25% had more than four brain lesions, eight (7%) achieved an objective response (one complete and seven partial), and 34 (29%) had stable disease in brain metastases. Median overall survival was 3.5 months. Among previously treated patients, 21% had more than four brain lesions, one had a partial response, and six (18%) had stable disease in brain metastases. Median overall survival was 2.2 months. Temozolomide was well tolerated, with four (3%) patients discontinuing because of adverse events. Grade 3/4 hematologic toxicities included thrombocytopenia (3%), neutropenia (2%), and leukopenia (1%). Headache (9%) and vomiting (8%) were the most common nonhematologic grade 3/4 adverse events. CONCLUSION: Temozolomide was well tolerated and demonstrated activity in the treatment of brain metastases from MM. Further evaluation of temozolomide combination therapy is warranted.

Adult↗
PubMed2006

Temozolomide: a milestone in neuro-oncology and beyond?

Temozolomide (Temodal, Temodar), an imidazol derivative, is a second-generation alkylating agent. The orally available prodrug with the capacity of crossing the blood-brain barrier received accelerated US FDA approval in 1999. Three pivotal Phase II trials showed modest activity in the treatment of recurrent anaplastic astrocytoma glioblastoma. In 2005, the FDA and the European Agency for the Evaluation of Medicinal Products approved temozolomide for use in newly diagnosed glioblastoma, in conjunction with radiotherapy, based on an European Organisation for Research and Treatment of Cancer/National Cancer Institute of Canada Phase III trial. The adverse events associated with temozolomide are mild-to-moderate and generally predictable; the most serious are noncumulative and reversible myelosuppression and, in particular, thrombocytopenia, which occurs in less than 5% of patients. Continuous temozolomide administration is associated with profound CD4-selective lymphocytopenia. Molecular studies have suggested that the benefit of temozolomide chemotherapy is restricted to patients whose tumors have a methylated methylguanine methyltransferase gene promotor and are thus unable to repair some of the chemotherapy-induced DNA damage. Temozolomide is under investigation for other disease entities, in particular lower-grade glioma, brain metastases and melanoma.

Antineoplastic Agents, Alkylating↗
PubMed2003

Use of temozolomide with other cytotoxic chemotherapy in the treatment of patients with recurrent brain metastases from lung cancer.

The use of chemotherapy for the treatment of brain metastases arising from lung cancer has been limited by poor efficacy and high toxicity. Temozolomide, an orally bioavailable alkylating agent that crosses the blood-brain barrier, has activity against brain metastases from both small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) when used as a single agent, but response rates are low. Preclinical experiments and early clinical studies in other malignancies indicate that temozolomide may have additive or synergistic effects when used with other chemotherapeutic agents. We report a case of a patient with SCLC with recurrent brain metastases after treatment with multiple chemotherapeutic regimens and whole-brain radiation therapy (WBRT) who was treated with temozolomide (150 mg/m(2) for 5 days in a 28-day cycle) and oral etoposide (50 mg/m(2) for 10 days in a 28-day cycle). A second patient with NSCLC and brain metastases who progressed after treatment with chemotherapy and WBRT was treated with temozolomide (150 mg/m(2) for 5 days in a 28-day cycle) and gemcitabine (1,000 mg/m(2) weekly for 2 weeks in a 3- week cycle). In both patients, the temozolomide regimens were extremely well tolerated and resulted in dramatic and durable responses. The combination of temozolomide with other chemotherapeutic agents represents a promising strategy for treating patients with lung cancer and recurrent brain metastases and merits further study.

Antineoplastic Agents, Alkylating↗
PubMed2003

Survival of patients with recurrent malignant glioma treated with temozolomide: a retrospective observational study.

OBJECTIVE: To assess whether the survival of patients with recurrent malignant glioma receiving temozolomide in everyday practice is comparable to that reported in previous studies. STUDY DESIGN: We conducted a retrospective observational study that included patients with recurrent malignant glioma who where treated with temozolomide. PATIENTS AND METHODS: The study was based on prospective clinical databases managed by the Italian Local Health Units; the databases are required by Italian Law 648/96 for patients treated with temozolomide before drug approval by the reimbursement agency of the Italian Ministry of Health. MAIN OUTCOME MEASURES AND RESULTS: 201 patients who had received temozolomide during the qualifying period of Law 648/96 for this drug (from 11 March 1998 to 30 September 2000) were included in our study. The clinical indications for temozolomide were glioblastoma multiforme (n = 123), anaplastic astrocytoma (n = 49) or other indications (n = 28). One patient did not have an indication reported. The median survival for patients with glioblastoma multi-forme and anaplastic astrocytoma was 13 and 20.3 months, respectively (with survival rates at 6 months of 81% and 78%, respectively). In our group of 49 patients with anaplastic astrocytoma, the survival plateau observed between 22 and 37 months (with no fatalities over this long time interval) suggested a favourable outcome, although restricted to a small subgroup. The 123 patients with glioblastoma multiforme showed a slightly better survival than that reported previously, but all patients died before 32 months. CONCLUSIONS: This observational study extends the previous information regarding the efficacy of temozolomide and provides survival data from patients treated in everyday practice.

Adult↗
PubMed2006

Enhancement of glioblastoma cell killing by combination treatment with temozolomide and tamoxifen or hypericin.

OBJECT: The chemotherapeutic agent temozolomide has demonstrated antitumor activity in patients with recurrent malignant glioma. Because responses are not enduring and recurrence is nearly universal, further improvements are urgently needed. METHODS: In an effort to increase the clinical activity of temozolomide, the authors investigated whether its antitumor activity could be enhanced by adding tamoxifen or hypericin, two drugs that are known to inhibit the activity of protein kinase C. Human glioblastoma multiforme cell lines A172 and LA567 were treated with combinations of temozolomide and tamoxifen or hypericin in vitro, and cell survival was analyzed using various methods. Tamoxifen and hypericin were able to greatly increase the growth-inhibitory and apoptosis-stimulatory potency of temozolomide via the downregulation of critical cell cycle-regulatory and prosurvival components. Furthermore, with the use of an in vivo xenograft mouse model, the authors demonstrated that hypericin was able to enhance the antiglioma effects of temozolomide in the in vivo setting as well. CONCLUSIONS: Taken together, analysis of the results indicated that combination therapy involving temozolomide and tamoxifen or hypericin potently inhibited tumor growth by inducing apoptosis and provided an effective means of treating malignant glioma.

Animals↗
PubMed2004

Sensitization of a human ovarian cancer cell line to temozolomide by simultaneous attenuation of the Bcl-2 antiapoptotic protein and DNA repair by O6-alkylguanine-DNA alkyltransferase.

Temozolomide is an alkylating agent that mediates its cytotoxic effects via O(6)-methylguanine (O(6)-meG) adducts in DNA. O(6)-alkylguanine-DNA-alkyltransferase (MGMT) can repair such adducts and therefore constitutes a major resistance mechanism to the drug. MGMT activity can be attenuated in vitro and in vivo by the pseudosubstrate O(6)-(4-bromothenyl)guanine (PaTrin-2, Patrin, Lomeguatrib), which in clinical trials is in combination with temozolomide. Resistance to cytotoxic agents can also be mediated by the Bcl-2 protein, which inhibits apoptosis and is frequently up-regulated in tumor cells. Attenuation of Bcl-2 expression can be affected by treatment of cells with the antisense oligonucleotide, oblimersen sodium (Genasense), currently in phase III clinical trials in combination with the methylating agent dacarbazine. Using a human ovarian cancer cell line (A2780) that expresses both Bcl-2 and MGMT, we show that cells treated with active dose levels of either oblimersen (but not control reverse sequence or mismatch oligonucleotides) or PaTrin-2 are substantially sensitized to temozolomide. Furthermore, the exposure of oblimersen-pretreated cells to PaTrin-2 leads to an even greater sensitization of these cells to temozolomide. Thus, growth of cells treated only with temozolomide (5 microg/mL) was 91% of control growth, whereas additional exposure to PaTrin-2 alone (10 micromol/L) or oblimersen alone (33 nmol/L) reduced this to 81% and 66%, respectively, and the combination of PaTrin-2 (10 micromol/L) and oblimersen (33 nmol/L) reduced growth to 25% of control. These results suggest that targeting both Bcl-2 with oblimersen and MGMT with PaTrin-2 would markedly enhance the antitumor activity of temozolomide and merits testing in clinical trials.

Antineoplastic Agents↗
PubMed2004

Temozolomide chemotherapy of patients with recurrent anaplastic astrocytomas and glioblastomas.

INTRODUCTION: Anaplastic astrocytomas and glioblastomas are the most frequent and most malignant hemispherial tumours. Unfortunately, astrocytic tumours are of infiltrative character and radical removal is not possible. Recurrent malignant gliomas are rarely suitable for reoperation. In most of the cases of recurrent gliomas chemotherapy is the last choice. PATIENTS AND METHOD: Seventy-five consecutive patients with recurrent malignant astrocytomas and glioblastomas had been treated at our institute with per os temozolomide for five days every month. The patients received two to 16 courses of chemotherapy. The toxicity, quality of life, response to chemotherapy and survival data were analysed. RESULTS: Out of 75 patients four were excluded following the first treatment due to myelotoxicity, and allergic reactions. Among the patients treated with temozolomide in seven cases complete response, 17 partial response, 14 progressive disease were observed. In 33 cases the disease stabilized and out of them in 27% a significant neurological improvement was detected. The time to progression was 6.8 months and the median survival time 8.75 months for patients with glioblastoma and with malignant astrocytoma or malignant mixed oligoastrocytoma 9.45 and 11.15 months, respectively. The overall survival for patients with originally lower grade glioma was 70.32 and for patients with glioblastoma multiforme 17.43 months. CONCLUSIONS: Temozolomide chemotherapy in patients with recurrent malignant astrocytoma and glioblastoma proved to be efficacious and similar good results were achieved as with a nitrosourea based combined chemotherapy. Even in those patients who received previous chemotherapy temozolomide is well tolerated and a relatively long time to progression was achieved in cases of recurrent malignant gliomas. In a few number of patients where BCNU had been previously failed with temozolomide stable disease was achieved. Temozolomide seems to be a promising drug in the chemotherapy of malignant gliomas and can be applied as a second line chemotherapy, as well.

Adult↗
PubMed1994

Preclinical antitumor activity of temozolomide in mice: efficacy against human brain tumor xenografts and synergism with 1,3-bis(2-chloroethyl)-1-nitrosourea.

Temozolomide, a methylating agent with clinical activity against brain tumors, demonstrated excellent antitumor activity following p.o. administration to athymic mice bearing human brain tumor xenografts. In the early stage s.c. implanted SNB-75 astrocytoma model, a 400-mg/kg dose administered on Day 5 produced 10 of 10 Day 54 tumor-free mice. In later staged s.c. U251 and SF-295 glioblastoma models, a single 600-mg/kg dose produced 9 of 10 Day 86 and 2 of 10 Day 40 tumor-free mice, respectively. In the latter group, a tumor growth delay of > 315% was attained. Similar levels of activity were attained with equal total doses on schedules of daily for 5 doses and every fourth day for 3 doses. A single 40-mg/kg i.v. dose of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) also demonstrated excellent activity, producing 9 of 10 tumor-free mice in the SNB-75 model and growth delays of 283 and 301% in the U251 and SF-295 models, respectively. Temozolomide was also highly effective against intracerebral implants of the U251 and SF-295 glioblastomas. Administration of either 600 mg/kg on Day 1 or 200 mg/kg on Days 1, 5, and 9 produced 7 of 9 Day 90 tumor-free mice in the U251 model. In the SF-295 model, a single 400-mg/kg dose or three 200-mg/kg doses produced 3 and 4 of 10 Day 90 tumor-free mice, respectively, and prolonged survival by 127%. A single 40-mg/kg i.v. dose of BCNU was more effective than temozolomide in the intracerebral SF-295 model, and less effective in the intracerebral U251 model. The synergistic potential of temozolomide and BCNU in combination was evaluated in an advanced stage s.c. implanted SF-295 model. When temozolomide was administered 2 h after BCNU on a single treatment day, a dramatic synergistic therapeutic effect was observed in two experiments. For example, single agent doses of temozolomide (600 mg/kg) and BCNU (60 mg/kg) and a combination (400 mg/kg + 27 mg/kg) demonstrating equivalent toxicity produced growth delays of 190, 258, and > 492% (includes 5 of 10 Day 51 tumor-free mice), respectively. Analysis of the data by a quadratic dose response model indicated synergism with significance at P = 0.0001 in both experiments. Synergism also was demonstrated by the isobole method. The reverse sequence was more toxic, but at lower combination doses a synergistic effect was still observed (P = 0.0001).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2000

O(6)-(4-bromothenyl)guanine improves the therapeutic index of temozolomide against A375M melanoma xenografts.

Tumour resistance to methylating agents is linked to expression of the DNA repair protein O(6)-alkylguanine-DNA alkyltransferase (ATase). There is considerable interest in improving the efficacy of O(6)-alkylating chemotherapy by prior depletion of ATase. We have tested the ability of a modified guanine base, O(6)-(4-bromothenyl)guanine (4BTG), to inactivate ATase and to enhance the anti-tumour effect of temozolomide in an animal model system. A375M human melanoma xenografts were established in the flanks of nude mice. ATase depletion after a single dose of 4BTG or O(6)-BG (20 mg/kg i.p.) was determined over a 24 hr period. Subsequently, we tested the effect of 4BTG (20 mg/kg i.p. daily) and/or temozolomide (80-175 mg/kg i.p. daily) over a 5-day schedule on tumour growth. 4BTG was an effective inactivator of ATase in tumour, producing complete depletion within 2 hr of dosing. Furthermore, it enhanced the tumour growth delay achieved with temozolomide, increasing the tumour quintupling time by 8.7 days (95% confidence interval 6.1-11.3 days, p < 0.0001). Whilst the delay in tumour growth was indistinguishable from that observed with O(6)-benzylguanine (O(6)-BG) and temozolomide, the 4BTG combination resulted in considerably less toxicity (0/9 vs. 2/9 deaths; 6.84% weight loss vs. 9.48%, p = 0.019). 4BTG is a potent inactivator of ATase and enhances the therapeutic ratio of temozolomide in this model system to a greater extent than O(6)-BG.

Adenosine Triphosphatases↗
PubMed2007

Temozolomide in advanced malignant melanoma with small brain metastases: can we withhold cranial irradiation?

BACKGROUND: The efficacy of radiotherapy (RT) in patients who have brain metastases from melanoma is limited. In this study, the authors evaluated the efficacy of treatment with temozolomide in patients with metastatic melanoma, including small brain metastases, who did not require immediate RT and investigated the feasibility of deferring RT. METHODS: Patients with brain metastasis were identified from 3 prospective studies of temozolomide (with or without immunotherapy) for metastatic melanoma. Patients with brain metastasis that measured >2 cm, extensive edema, and localization in the brain stem were excluded from the study. For the current analysis, patients with leptomeningeal metastasis and patients who received previous stereotactic RT were excluded. In patients who achieved a systemic response or stabilization to temozolomide, the response of brain metastasis and the necessity for palliative cranial RT were evaluated. RESULTS: Among 179 patients who received temozolomide for advanced melanoma, 52 patients with brain metastasis were evaluable. Stabilization of systemic metastasis was noted in 7 of 52 patients (13%), and there were 6 responses (5 partial responses and 1 complete response; 11%); thus, in those 13 patients, 6 had stabilization of brain metastasis (11%) and 5 had a response (2 partial responses and 3 complete responses; 9%). Immunotherapy did not influence the neurologic response. The median time to neurologic progression was 7 months (range 2-15, months). RT for cerebral recurrence was required in 2 patients. The median survival of patients with brain metastases was 5.6 months (95% confidence interval, 4.4-6.8 months). Intracranial hemorrhagic complications were not observed. CONCLUSIONS: The current results indicated that it is feasible to treat patients who have advanced melanoma and small brain metastasis with temozolomide as the single treatment. The small subset of patients with systemic response usually showed durable stabilization or a response of brain metastasis. With this approach, neurologic disease can be controlled, and cranial irradiation may be deferred and even withheld in most of patients.

Adult↗
PubMed2007

Temozolomide and intravenous irinotecan for treatment of advanced Ewing sarcoma.

BACKGROUND: Preclinical models show sequence-dependent synergy with the combination of temozolomide and irinotecan, and a Phase I trial has demonstrated the combination to be tolerable and active in children with relapsed solid tumors. Because responses were seen in patients with Ewing sarcoma (ES) on that trial, additional patients were treated with this combination following study completion. PROCEDURE: We reviewed data from all ES patients treated with temozolomide and irinotecan at four institutions, including seven patients treated on the above Phase I trial. RESULTS: Sixteen patients received a total of 95 courses, with a median of five courses per patient. All patients had either progressive disease (PD) during initial therapy (n = 5) or relapse within 2 years of diagnosis (n = 11). Twelve patients had metastatic disease at diagnosis, including 5 with bone and/or marrow metastases. Patients received oral temozolomide 100 mg/m(2)/day on days 1-5 plus intravenous irinotecan 10-20 mg/m(2)/day on days 1-5 and 8-12, with courses repeated every 21-28 days. We observed 1 complete, 3 partial, and 3 minor responses in 14 evaluable patients, with a median duration of response of 30 weeks. Planned 21-day courses were tolerable and no more toxic than 28-day courses. Myelosuppression was minimal despite heavy pretreatment. Grade 3-4 diarrhea occurred in 11% of courses and was related to higher irinotecan doses. Over 600 irinotecan doses were administered uneventfully at home. CONCLUSIONS: Temozolomide and protracted intravenous irinotecan given in 21-day courses was tolerable and active in patients with advanced ES. Home administration of irinotecan with temozolomide was safe and is reasonable palliative therapy. A formal Phase II study using a uniform dose and schedule is warranted to better define activity.

Administration, Oral↗