Phase II Trial of Temozolomide Plus O6-Benzylguanine in Adults With Recurrent, Temozolomide-Resistant Malignant Glioma
Jennifer A. QuinnXiaoyin “Sara” JiangDavid A. ReardonAnnick DesjardinsJames J. VredenburghJeremy N. RichSridharan GururanganAllan H. FriedmanDarell D. BignerJohn H. SampsonRoger E. McLendonJames E. HerndonAmy WalkerHenry S. Friedman
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Purpose This phase II trial was designed to define the role of O 6 -benzylguanine (O 6 -BG) in restoring temozolomide sensitivity in patients with recurrent or progressive, temozolomide-resistant malignant glioma and to evaluate the safety of administering O 6 -BG in combination with temozolomide. Patients and Methods Patients were accrued into two independent strata on the basis of histology: glioblastoma multiforme (GBM) and anaplastic glioma. Both temozolomide and O 6 -BG were administered on day 1 of a 28-day treatment cycle. Patients were administered a 1-hour O 6 -BG infusion at a dose of 120 mg/m 2 followed immediately by a 48-hour infusion at a dose of 30 mg/m 2 /d. Temozolomide was administered orally within 60 minutes of the end of the 1-hour O 6 -BG infusion at a dose of 472 mg/m 2 . The primary end point was objective response rate. Secondary end points included progression-free survival, overall survival, and safety. Results Sixty-six of 67 patients who enrolled were treated with temozolomide and O 6 -BG. One of 34 patients (3%) with GBM (95% CI, 0.1% to 15%) and five of 32 assessable patients (16%) with anaplastic glioma (95% CI, 5% to 33%) were responders. The most commonly reported adverse events were grade 4 hematologic events experienced in 48% of the patients. Conclusion O 6 -BG when added to a 1-day dosing regimen of temozolomide was able to restore temozolomide sensitivity in patients with temozolomide-resistant anaplastic glioma, but there seemed to be no significant restoration of temozolomide sensitivity in patients with temozolomide-resistant GBM.Keywords:
Temozolomide
Regimen
Dacarbazine
Clinical endpoint
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.
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Purpose This phase II trial was designed to define the role of O 6 -benzylguanine (O 6 -BG) in restoring temozolomide sensitivity in patients with recurrent or progressive, temozolomide-resistant malignant glioma and to evaluate the safety of administering O 6 -BG in combination with temozolomide. Patients and Methods Patients were accrued into two independent strata on the basis of histology: glioblastoma multiforme (GBM) and anaplastic glioma. Both temozolomide and O 6 -BG were administered on day 1 of a 28-day treatment cycle. Patients were administered a 1-hour O 6 -BG infusion at a dose of 120 mg/m 2 followed immediately by a 48-hour infusion at a dose of 30 mg/m 2 /d. Temozolomide was administered orally within 60 minutes of the end of the 1-hour O 6 -BG infusion at a dose of 472 mg/m 2 . The primary end point was objective response rate. Secondary end points included progression-free survival, overall survival, and safety. Results Sixty-six of 67 patients who enrolled were treated with temozolomide and O 6 -BG. One of 34 patients (3%) with GBM (95% CI, 0.1% to 15%) and five of 32 assessable patients (16%) with anaplastic glioma (95% CI, 5% to 33%) were responders. The most commonly reported adverse events were grade 4 hematologic events experienced in 48% of the patients. Conclusion O 6 -BG when added to a 1-day dosing regimen of temozolomide was able to restore temozolomide sensitivity in patients with temozolomide-resistant anaplastic glioma, but there seemed to be no significant restoration of temozolomide sensitivity in patients with temozolomide-resistant GBM.
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Purpose: Temozolomide is an imidazotetrazine with a mechanism of action similar to dacarbazine and equivalent activity in melanoma. It is well tolerated and is a candidate for combination chemotherapy and schedule manipulation. In this study, we combined temozolomide with interferon alfa-2b and, separately, with thalidomide, and we administered temozolomide alone in a compressed schedule. The objectives of this randomized phase II, two-center study were to determine response rates, overall survival, and tolerability of the regimens in patients with advanced metastatic melanoma. Patients and Methods: One hundred eighty-one patients with metastatic melanoma were randomly assigned to receive up to six 4-weekly cycles consisting of temozolomide 200 mg/m 2 every 8 hours for five doses, or temozolomide 200 mg/m 2 daily for days 1 to 5 plus interferon alfa-2b 5 MU (million International Units) subcutaneously three times a week, or temozolomide 150 mg/m 2 (increased after one cycle to 200 mg/m 2 ) daily on days 1 to 5 plus thalidomide 100 mg daily days 1 to 28. Results: The treatment arms were well balanced for known prognostic factors. Median survival was 5.3 months for 8-hourly temozolomide, 7.7 months for temozolomide/interferon, and 7.3 months for temozolomide/thalidomide; and 1-year survivals were 18%, 26%, and 24%, respectively. Response or disease stabilization occurred in 20% of patients (95% confidence interval [CI], 10% to 33%) given 8-hourly temozolomide, 21% (95% CI, 12% to 33%) given temozolomide/interferon, and 25% (95% CI, 15% to 38%) given temozolomide/thalidomide. Grade 3 or 4 nonhematologic toxicities were similar in each arm except for infection, which was more frequent with 8-hourly temozolomide. There were fewer instances of grade 3 or 4 myelotoxicity with temozolomide/thalidomide. Conclusion: Of the three regimens tested, the combination of temozolomide and thalidomide seems the most promising for future study.
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Over the past 30 years, there has been no significant improvement in treatment outcomes for patients with advanced stage IV metastatic melanoma, and prognosis remains poor. Melanoma is known to be responsive to immunomodulatory agents, to be a highly vascular tumor, and to be fairly resistant to standard cytotoxic chemotherapy. Ongoing research is attempting to find novel combinations that may have therapeutic synergy. Alternative dose-dense schedules of temozolomide appear promising and are being actively investigated, based on their potential to overcome chemoresistance to alkylating agents and the proven activity of temozolomide in the brain. Outcomes of studies investigating single-agent temozolomide suggest that it has activity similar to single-agent dacarbazine. Other studies combining temozolomide with either interferon-alfa or thalidomide suggest that the addition of these immunomodulatory agents to temozolomide improves response rates and may improve overall survival. The best results have been achieved with the extended, daily, dose-dense temozolomide regimen. Further research is needed to determine the optimal temozolomide regimen and best combination approach for the treatment of advanced metastatic melanoma.
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Over the past 30 years, there has been no significant improvement in treatment outcomes for patients with advanced stage IV metastatic melanoma, and prognosis remains poor. Melanoma is known to be responsive to immunomodulatory agents, to be a highly vascular tumor, and to be fairly resistant to standard cytotoxic chemotherapy. Ongoing research is attempting to find novel combinations that may have therapeutic synergy. Alternative dosedense schedules of temozolomide appear promising and are being actively investigated, based on their potential to overcome chemoresistance to alkylating agents and the proven activity of temozolomide in the brain. Outcomes of studies investigating single-agent temozolomide suggest that it has activity similar to single-agent dacarbazine. Other studies combining temozolomide with either interferon- alfa or thalidomide suggest that the addition of these immunomodulatory agents to temozolomide improves response rates and may improve overall survival. The best results have been achieved with the extended, daily, dosedense temozolomide regimen. Further research is needed to determine the optimal temozolomide regimen and best combination approach
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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.
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Temozolomide is an imidazotetrazine with a mechanism of action and efficacy similar to dacarbazine (DTIC). However, it differs from DTIC in that it can be taken orally, degrades spontaneously to an active metabolite and penetrates the blood–brain barrier. It is well tolerated, making it a suitable candidate for combination chemotherapy. Trials to date have focussed on its activity in advanced metastatic melanoma and high-grade malignant glioma. Investigations into other indications, in particular solid tumors with central nervous system metastases, are ongoing. Studies of new drug schedules and of drugs to ameliorate temozolomide resistance offer the prospect of increased efficacy.
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Abstract Background. This systematic review examines the role of temozolomide in patients with metastatic melanoma. Outcomes of interest include response rate, progression-free survival, overall survival, quality of life, and adverse effects. Methods. The MEDLINE, EMBASE, and Cochrane Library databases were searched from 1980 through to 2005 using variations on the search terms: melanoma, clinical trial, random, temozolomide, temodal, and temodar. The American Society of Clinical Oncology Annual Meeting proceedings were searched from 1996 to 2005. Relevant articles and abstracts were selected and reviewed by two reviewers, and the reference lists from these sources were searched for additional trials. Results. Two randomized phase III trials and three randomized phase II trials were located. In addition, 21 phase I or II trials investigating single-agent temozolomide, temozolomide plus interferon-α, and temozolomide plus thalidomide were reviewed. A direct comparison of temozolomide and dacarbazine demonstrated equal efficacy for response rates and overall survival; however, no significant difference was reported. A second phase III study comparing single-agent temozolomide with temozolomide combined with interferon-α indicated a significantly higher response rate for the combination treatment arm, but no difference in overall survival was noted. Further phase III studies are required to confirm whether there is a benefit associated with the combination of temozolomide and interferon-α or thalidomide. Conclusion. Our review of the available literature suggests that temozolomide demonstrates comparable activity to the current standard treatment, dacarbazine, with the additional benefit of being a convenient oral treatment that penetrates the blood–brain barrier.
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The purpose of this study was to evaluate the activity, measured in terms of progression-free survival (PFS) and response rates, of 1,3-bis(chloro-ethyl)-1-nitrosourea (BCNU) plus temozolomide in adult patients with recurrent glioblastoma multiforme.The phase 2 dose and schedule for this trial was BCNU 150 mg/m 2 i.v.followed in 2 h by temozolomide 550 mg/m 2 as a single oral dose.Treatment was repeated every 6 weeks for up to 8 cycles unless tumor progression was documented.The
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Temozolomide (Temodar) has demonstrated clinical activity against melanoma equivalent to that of intravenous dacarbazine (DTIC). Phase I clinical studies have shown that low dose chronic administration of temozolomide permits the delivery of higher dose intensities than a 5 day dose schedule. Temozolomide is hydrolysed to its active metabolite monomethyltriazenoimidazole carboxamide (MTIC) upon absorption from the gastrointestinal tract, while DTIC is inactive until it is metabolized in the liver to MTIC. In view of this, a higher concentration of MTIC will pass through the liver during the first pass when its source is temozolomide rather than DTIC. To determine if these characteristics of temozolomide will translate into a higher response rate than that achieved with DTIC, we conducted a phase II clinical trial of temozolomide in patients with uveal melanoma metastatic to the liver. Temozolomide was administered orally at a starting dose of 75 mg/m2 per day for 21 days every 4 weeks. Fourteen patients were enrolled in the trial. No complete or partial responses were observed. Stabilization of disease was achieved in two patients. The treatments were well tolerated. We conclude that, like DTIC, temozolomide at the dose and schedule studied in this trial is not effective for the control of metastatic melanoma of uveal origin.
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