Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027947 (neutropenia)
 17,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Temozolomide (SCH 52365) is an imidazotetrazine derivative which exhibits broad spectrum activity against murine tumors and is structurally related to dacarbazine (DTIC). Temozolomide cytotoxicity is schedule dependent in vivo with a daily x 5 schedule showing the highest activity. Oral temozolomide is rapidly and completely absorbed with minimal interpatient and intrapatient variability in pharmacokinetics. Clinical studies have demonstrated activity against melanoma and glioma. The present study examined the activity of oral temozolomide against patients with pancreatic cancer. Patients with advanced pancreatic adenocarcinoma previously untreated with chemotherapy received temozolomide 200 mg/m2/day once daily orally for 5 days with cycles repeated every 28 days. There were 16 patients entered on study with 15 evaluable for response and toxicity. There were no responses seen in 15 evaluable patients with 14 manifesting progressive disease within 2 months of starting therapy. Toxicity was primarily hematological with 3 patients experiencing > or = grade 3 neutropenia and thrombocytopenia respectively. Other toxicities were relatively modest. In conclusion, temozolomide in the once daily x 5 schedule is inactive against adenocarcinoma of the pancreas.
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PMID:A phase II study of temozolomide in advanced untreated pancreatic cancer. 974 May 47

Temozolomide (TMZ) is an oral imidazotetrazinone that is spontaneously converted to 5-(3-methyltriazen-1-yl)imidazole-4-carboxamide (MTIC) at physiological pH. MTIC methylates DNA at the O6 position of guanine, although this lesion may be repaired by the enzyme O6-alkylguanine-DNA alkyltransferase (AGAT). In this study, TMZ was combined with cisplatin (CDDP), because both agents have single-agent activity against melanoma and other tumor types. Additionally, CDDP has been shown to inactivate AGAT, and subtherapeutic concentrations of CDDP have been shown to increase the sensitivity of leukemic blasts to TMZ. This Phase I study sought to determine the toxicities, recommended dose, and pharmacological profile of the TMZ/CDDP combination. Patients were treated with oral TMZ daily for 5 consecutive days together with CDDP on day 1 (4 h after TMZ) every 4 weeks at the following TMZ (mg/m2/day)/CDDP (mg/m2) dose levels: 100/75, 150/75, 200/75, and 200/100. Plasma samples were obtained on days 1 and 2 to evaluate the pharmacokinetic parameters of TMZ alone and in combination with CDDP. Fifteen patients received a total of 44 courses of TMZ/CDDP. The principal toxicities of the regimen consisted of neutropenia, thrombocytopenia, nausea, and vomiting, which were intolerable in two of six new patients treated at the 200/100 mg/m2 dose level. Of five patients receiving 17 courses at the next lower dose level (200/75 mg/m2), none experienced dose-limiting toxicity. Antitumor activity was observed in patients with non-small cell lung cancer, squamous cell carcinoma of the tongue, and leiomyosarcoma of the uterus. Pharmacokinetic studies of TMZ revealed the following pertinent parameters (mean +/- SD): time to maximum plasma concentration (Tmax) = 1.1+/-0.6 h (day 1) and 1.7+/-0.9 h (day 2); elimination half-life (t1/2) = 1.74+/-0.22 h (day 1) and 2.35+/-0.70 h (day 2); and clearance (Cl(s)/F) = 115+/-27 ml/min/m2 (day 1) and 141+/-109 ml/min/m2 (day 2). TMZ drug exposure, described by the area under the plasma concentration-time curve (AUCinfinity) and the maximum plasma concentration (Cmax), was similar on days 1 and 2. On the basis of these results, the recommended doses for Phase II clinical trials are TMZ 200 mg/m2/day for 5 days with 75 mg/m2 CDDP on day 1, every 4 weeks. The addition of CDDP did not affect the tolerable dose of single-agent TMZ (200 mg/m2/day x 5 days), nor did it substantially alter the pharmacokinetic behavior of TMZ.
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PMID:A Phase I and pharmacokinetic study of temozolomide and cisplatin in patients with advanced solid malignancies. 1043 61

Temozolomide has an evolving role in the treatment of high grade gliomas. Recent studies suggest that temozolomide is well tolerated and efficacious. This study retrospectively analysed the activity and toxicity associated with temozolomide at two Australian centres over a 24 month period. Fifty-six patients with recurrent high grade gliomas were treated with temozolomide. Patients received temozolomide orally at 150-200mg/m(2)daily, days 1-5, every 4 weeks. The median number of treatment cycles was 4 (1-12). Of the 56 patients, 15 (27%) achieved complete or partial response and 18 (32%) achieved minor response or stable disease. There were no episodes of febrile neutropenia and temozolomide was generally well tolerated. In conclusion, temozolomide is an active therapy in patients with recurrent high grade glioma and our results concord with published studies.
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PMID:An Australian experience with temozolomide for the treatment of recurrent high grade gliomas. 1143 71

Temozolomide (TMZ) is a methylating agent of the imidotetrazine class, whose cytotoxic product is O(6)-methylguanine DNA adducts, which initiate a futile recycling of the mismatch repair pathway causing DNA strand breaks and apoptotic cell death in mismatch repair proficient cells. The DNA repair protein O(6)-alkylguanine DNA alkyltransferase (AGT) repairs these adducts in a suicide manner and reduces the cytotoxic action of TMZ. An antitumor threshold is reached when sufficient adducts are formed by TMZ to inactivate AGT. In this study, we evaluated the relation between TMZ dosing and AGT depletion in patients with deep visceral tumors and in peripheral blood mononuclear cells (PBMCs) to determine whether the dose of TMZ was sufficient to inactivate AGT and lead to therapeutic efficacy. To do so, we compared single dose therapy with a novel twice daily regimen in a laboratory correlate-driven Phase I dose escalation study. p.o. bolus dose TMZ 200 mg/m(2) daily times five was compared with the same bolus on day 1 followed by nine doses at 12-h intervals of 50, 75, 90, or 100 mg/m(2). Dose-limiting toxicity in the bid regimen (grade IV thrombocytopenia and neutropenia) was seen at 100 mg/m(2), cumulative dose 1100 mg/m(2), and the maximum tolerated dose was 1010 mg/m(2). The degree of tumor tissue AGT activity depletion measured in biopsies before and on day 5 of therapy varied widely, between 0 (in 3 patients) and 99% (in 1), with the majority of patients (10 of 15) having 52-84% tumor AGT depletion. In contrast, AGT activity in PBMCs fell rapidly during TMZ administration to undetectable levels in all dosage groups on day 5 but did not correlate with tumor AGT depletion. TMZ pharmacokinetics were dose proportional; no accumulation occurred >5-day period in the bid regimen. Two partial responses were seen, lasting 3 and 4 months. Five additional patients achieved prolonged stabilization of disease for 4-6 monthly cycles. This is the first study to document that at maximum tolerated doses, TMZ depletes PBMC AGT but only partially and variably depletes visceral tumor AGT in most patients, even during twice daily dosing. Drug combinations or schedules designed to maximally deplete tumor AGT might improve TMZ efficacy.
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PMID:Temozolomide: the effect of once- and twice-a-day dosing on tumor tissue levels of the DNA repair protein O(6)-alkylguanine-DNA-alkyltransferase. 1148 6

Temozolomide is an effective agent in the treatment of recurrent malignant gliomas. The standard dosage is 150-200 mg/m2 per day for 5 days in a 28-day cycle. A prior phase I study established a chronic daily temozolomide dose that significantly increased the total dose administered and suggested a superior response rate. In a prospective phase II trial, we treated 35 patients with recurrent malignant gliomas with temozolomide 75 mg/m2 per day for 42 consecutive days in a 70-day cycle. Median age was 55 years (range, 27-73 years) and median Karnofsky performance score was 70 (range, 60-90). Twenty-eight (79%) patients had glioblastoma multiforme, 3 (9%) anaplastic astrocytoma, 2 (6%) anaplastic oligodendroglioma, and 2 (6%) anaplastic oligoastrocytoma. All but one had prior radiotherapy, and 27 had prior chemotherapy. There were 2 partial (anaplastic astrocytoma) and 3 minor (glioblastoma multiforme) radiographic responses; 17 patients had progressive disease at the end of the first cycle. In 55 cycles of temozolomide, there were 8 episodes of asymptomatic drug-related grade 3 toxicity: 6 lymphopenia, 1 neutropenia, and 1 thrombocytopenia. Median progression-free survival and overall survival were 2.5 and 8.7 months (2.3 and 7.7 months in glioblastoma multiforme patients). At 6 months, progression-free survival and overall survival rates were 27% and 67% (19% and 60% in glioblastoma multiforme). Quality of life scores did not change significantly during treatment. We conclude that the extended low-dose schedule of temozolomide is well tolerated in heavily pre-treated patients; however, our results do not support an improved rate of response or survival.
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PMID:A phase II study of extended low-dose temozolomide in recurrent malignant gliomas. 1177 31

Temozolomide has established activity in the treatment of recurrent glioblastoma multiforme (GBM). Caelyx (liposomal doxorubicin) has established activity in a broad range of tumors but has not been extensively evaluated in the treatment of GBM. Phase 1 data suggest that temozolomide and Caelyx can be combined safely at full dose. In this phase 2 study, combination temozolomide (200 mg/m(2) orally, days 1-5) and Caelyx (40 mg/m(2) i.v., day 1) was given every 4 weeks to a cohort of 22 patients with recurrent GBM, who received a total of 109 cycles (median 3.5 cycles). The median age of the patients was 55 years (range, 31-80 years), and 17 were male. All patients had received radiotherapy, but only 2 had received prior chemotherapy. One patient (5%) had a complete response, 3 patients (14%) had a partial response, and 11 patients (50%) had stable disease. The median time to progression for the cohort was 3.2 months (range, 1-13 months). Median overall survival was 8.2 months (range, 1-16+ months). Seven patients (32%) were progression free at 6 months. Hematological toxicity included grade 3/4 neutropenia in 4 patients (18%) and grade 3/4 thrombocytopenia in 4 patients (18%). Grade 3 non-hematologic toxicity included rash in 3 patients (14%), nausea and vomiting in 1 patient (4%), hypersensitivity reaction to Caelyx in 3 patients (14%), and palmar-plantar toxicity in 1 patient (4%). We conclude that the combination of temozolomide and Caelyx is well tolerated, results in a modest objective response rate, but has encouraging disease stabilization in the treatment of recurrent GBM.
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PMID:Phase 2 study of temozolomide and Caelyx in patients with recurrent glioblastoma multiforme. 1476 39

Cerebral metastases from melanoma are correlated with a poor prognosis. Temozolomide is an oral alkylating agent that can cross the blood-brain barrier and in phase II and III trials, patients with advanced metastatic melanoma achieved overall response rates of 13 to 21%. The present study evaluated the efficacy and toxicity of temozolomide-based chemotherapy in patients with cerebral metastases from melanoma. Twenty-five patients (median age 48 years) with histologically confirmed stage IV melanoma and cerebral metastases treated with temozolomide-based chemotherapy. 10 patients received temozolomide plus docetaxel, nine patients temozolomide plus cisplatin and six patients temozolomide as single agent. Six patients achieved an objective response (24%). All responses were partial. The disease was stable in five patients (20%) and 13 patients progressed (52%). The median response duration was 6.9 months (range 1.8 to 16 months). The median time to progression (TTP) for all patients was 2 months, compared with a median TTP of 3.9 months, among responders and a median TTP of 1.8 months, for patients who remained stable or progressed (P<0.0001). The median survival time for the entire patient population was 4.7 months. The median survival for responders was 5.5 months and for non-responders was 3.6 months. The difference was statistically significant (P<0.05). The toxicity was mild. The most frequently reported adverse event were myelotoxicity and nausea and vomiting. Four patients developed grade 3/4 leukopenia, two grade 4 neutropenia, and one patient developed grade 3 thrombocytopenia. There was no treatment discontinuation caused by toxicity. Temozolomide-based chemotherapy may have a role in patients with cerebral metastases from melanoma. Further exploration is required. Toxicity was manageable.
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PMID:The effect of temozolomide-based chemotherapy in patients with cerebral metastases from melanoma. 1530 60

Temozolomide (TMZ) has shown modest efficacy in the treatment of recurrent brain metastasis (BM). We designed a new regimen utilizing dose-intensified, protracted course of TMZ in combination with vinorelbine, a lipophilic large-spectrum agent, in an attempt to improve the efficacy of TMZ. This phase I study was conducted to establish the maximum tolerated dose (MTD) of vinorelbine for this combination. Patients with recurrent or progressive BM were eligible. Chemotherapy consisted of 28-day cycles with TMZ (150 mg/m2, days 1-7 and 15-21) and vinorelbine (days one and eight at escalating doses). The starting dose was 15 mg/m2, with increments of 5 mg/m2 for each cohort of 3-6 patients, until MTD was reached (30 mg/m2). A total of 21 patients were enrolled; the median age was 59 (41-77). The primary tumor was lung cancer in 13 patients (NSCLC in 10, SCLC in 3), breast in 6, renal in 1 and endometrial in 1. Vinorelbine dose was 15 mg/m2 in seven patients, 20 mg/m2 in five, 25 mg/m2 in four and 30 mg/m2 in six. Grades 3 and 4 neutropenia developed in six patients, lymphopenia in nine, and thrombocytopenia in six; other toxicities were rare. No dose-limiting toxicity was seen. Out of 18 evaluable patients 2 had a radiographic response (one partial and one minor). Disease was stable in 6 of 18 patients and the median survival was 27 weeks. This regimen was well tolerated and a phase II trial using a dose of 30 mg/m2 of vinorelbine is warranted.
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PMID:Vinorelbine combined with a protracted course of temozolomide for recurrent brain metastases: a phase I trial. 1661 43

The efficacy and safety of temozolomide were evaluated in 32 patients with anaplastic astrocytoma at first relapse. Temozolomide was administered orally once daily for the first five days of a 28-day cycle, at a dose of 150 or 200 mg/m(2)/day. The response rate determined by independent central review of MRI was 34% (95% confidence interval: 18.6%-53.2%), with 3 complete response and 8 partial response. The rate of "no change or better" was 91% (95% confidence interval: 75.0%-98.0%). Progression-free survival (PFS) at 6 months was 40.6%, and the median PFS was 4.1 months. The incidence of constipation (50%) and nausea (25%) was high,but these events were all mild or moderate in severity except in one subject with constipation,and could be managed with standard laxatives and antiemetics. The main laboratory test abnormalities (total incidence and incidence of grade 3/4 change) were lymphocytopenia (50%, 25%), neutropenia (47%, 6%), leukopenia (38%, 3%), thrombocytopenia (31%, 9%), and increased GPT (25%, 3%). Temozolomide was shown to have good efficacy and tolerability in patients with anaplastic astrocytoma at first relapse.
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PMID:[Efficacy and safety of monotherapy with temozolomide in patients with anaplastic astrocytoma at first relapse--a phase II clinical study]. 1696 25

Temozolomide (TMZ) administered daily with radiation therapy (RT) for six weeks, followed by adjuvant TMZ for six months, has become standard therapy for patients with glioblastoma multiforme (GBM). After several newly diagnosed patients at our institution developed severe (grade 3-4), prolonged thrombocytopenia, we conducted a retrospective review to define the incidence, depth, and duration of thrombocytopenia associated with this therapy. We reviewed the medical records and laboratory data of all adult patients with newly diagnosed high-grade gliomas who started treatment with this regimen between June 2004, when the regimen was first used at our institution, and August 2005. Of the 52 patients who met the criteria for this review, grade 3-4 thrombocytopenia occurred in 10 (19%; 95% CI, 10%-33%). In eight patients, the thrombocytopenia was attributable to concurrent daily TMZ and RT. The median duration of grade 3-4 thrombocytopenia was 32 days (range, 1-389 days). Five patients (10%) required platelet transfusions, two (4%) have required continued biweekly platelet transfusions for over six months, and nine (17%) discontinued therapy because of thrombocytopenia. Grade 3-4 thrombocytopenia occurred in 25% of women and 14% of men. Grade 3-4 neutropenia and anemia were noted in 10% and 8% of patients, respectively, and were not clinically significant. Between 15% and 20% of our newly diagnosed patients receiving TMZ and RT developed severe (grade 3-4) and potentially irreversible thrombocytopenia. The factors that predispose patients to this toxicity have yet to be determined. This toxicity should be considered when (1) prescribing this regimen to patient populations where a clinical benefit has yet to be shown, (2) contemplating empirical escalations of the dose or duration of TMZ, or (3) combining it with other potentially myelosuppressive therapies.
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PMID:The impact of thrombocytopenia from temozolomide and radiation in newly diagnosed adults with high-grade gliomas. 1710 62


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