Dataset Information

Prolonged survival with valproic acid use in the EORTC/NCIC temozolomide trial for glioblastoma.

ABSTRACT:

Objective

This analysis was performed to assess whether antiepileptic drugs (AEDs) modulate the effectiveness of temozolomide radiochemotherapy in patients with newly diagnosed glioblastoma.

Methods

The European Organization for Research and Treatment of Cancer (EORTC) 26981-22981/National Cancer Institute of Canada (NCIC) CE.3 clinical trial database of radiotherapy (RT) with or without temozolomide (TMZ) for newly diagnosed glioblastoma was examined to assess the impact of the interaction between AED use and chemoradiotherapy on survival. Data were adjusted for known prognostic factors.

Results

When treatment began, 175 patients (30.5%) were AED-free, 277 (48.3%) were taking any enzyme-inducing AED (EIAED) and 135 (23.4%) were taking any non-EIAED. Patients receiving valproic acid (VPA) only had more grade 3/4 thrombopenia and leukopenia than patients without an AED or patients taking an EIAED only. The overall survival (OS) of patients who were receiving an AED at baseline vs not receiving any AED was similar. Patients receiving VPA alone (97 [16.9%]) appeared to derive more survival benefit from TMZ/RT (hazard ratio [HR] 0.39, 95% confidence interval [CI] 0.24-0.63) than patients receiving an EIAED only (252 [44%]) (HR 0.69, 95% CI 0.53-0.90) or patients not receiving any AED (HR 0.67, 95% CI 0.49-0.93).

Conclusions

VPA may be preferred over an EIAED in patients with glioblastoma who require an AED during TMZ-based chemoradiotherapy. Future studies are needed to determine whether VPA increases TMZ bioavailability or acts as an inhibitor of histone deacetylases and thereby sensitizes for radiochemotherapy in vivo.

SUBMITTER: Weller M

PROVIDER: S-EPMC3265044 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BACKGROUND: The EORTC (26981-22981)/NCIC CTG (CE.3) RCT in newly diagnosed GBM showed increased survival with concomitant and adjuvant temozolomide (TMZ) added to radiotherapy (RT). Study pts were 18-71 (median 56) years; however a sub-group analysis noted a trend of decreasing benefit from the addition of TMZ with increasing age, such that for age 65-71, the hazard ratio of 0.8 did not reach statistical significance (p = 0.340). This may reflect a lack of efficacy in elderly patients, or simply be due to a lack of statistical power in this subgroup. Recent RCTs in elderly GBM found improved survival with RT compared to supportive care alone and detected non-inferiority of 40 Gy/15 vs. a 60 Gy/30 RT regimen and superior survival was noted for MGMT-methylated patients treated with TMZ alone vs RT alone. Based upon these results short-course hypofractionated RT is often recommended for elderly pts. However, whether the addition of TMZ to RT confers a survival advantage in elderly pts, particularly for those with methylated MGMT, remains unanswered. METHODS: We conducted a global randomized phase III clinical trial for patients ≥65 yrs of age with histologically confirmed newly diagnosed glioblastoma, ECOG 0-2, randomized 1:1 to receive 40Gy/15 RT vs. 40Gy/15 RT with 3 weeks of concomitant temozolomide plus monthly adjuvant TMZ until progression or 12 cycles. Stratification is by centre, age (65-70, 71-75, or 76+), ECOG 0,1 vs 2, and biopsy vs resection. RESULTS: Accrual of n = 562 patients was completed Sept 19, 2013. Accrual by participating group was NCIC CTG 199, EORTC 249, TROG 97, and Japan 17 patients. Median age of randomized patients was 73 (65-90) years with 70% of patients over the age of 71. The study was powered to detect a HR of 0.75 in median OS, requiring 520 events for analysis. At the time of writing the required number of deaths had not been reached. A comprehensive analysis, including MGMT promoter methylation and QOL, is planned. CONCLUSIONS: A global cooperative group trial was completed randomizing 562 elderly patients with glioblastoma. The final results will add to our knowledge on the optimal treatment of these patients. SECONDARY CATEGORY: n/a.

Project description:BackgroundThe impact of prolonging temozolomide (TMZ) maintenance beyond six cycles in newly diagnosed glioblastoma (GBM) remains a topic of discussion. We investigated the effects of prolonged TMZ maintenance on progression-free survival (PFS) and overall survival (OS).Patients and methodsIn this retrospective single-center cohort study, we included patients with GBM who were treated with radiation therapy with concomitant and adjuvant TMZ. For analysis, patients were considered who either completed six TMZ maintenance cycles (group B), continued with TMZ therapy beyond six cycles (group C), or stopped TMZ maintenance therapy within the first six cycles (group A). Patients with progression during the first six TMZ maintenance cycles were excluded.ResultsClinical data from 107 patients were included for Kaplan-Meier analyses and 102 for Cox regressions. Median PFS times were 8.1 months (95% confidence interval [CI] 6.1-12.4) in group A, 13.7 months (95% CI 10.6-17.5) in group B, and 20.9 months (95% CI 15.2-43.5) in group C. At first progression, response rates of TMZ/lomustine rechallenge were 47% in group B and 13% in group C. Median OS times were 12.7 months (95% CI 10.3-16.8) in group A, 25.2 months (95% CI 17.7-55.5) in group B, and 28.6 months (95% CI 24.4-open) in group C. Nevertheless, multivariate Cox regression for patients in group C compared with group B that accounted for imbalances of other risk factors showed no different relative risk (RR) for OS (RR 0.77, p = .46).ConclusionOur data do not support a general extension of TMZ maintenance therapy beyond six cycles. The Oncologist 2017;22:570-575 IMPLICATIONS FOR PRACTICE: Radiation therapy with concomitant and adjuvant temozolomide (TMZ) maintenance therapy is still the standard of care in patients below the age of 65 years in newly diagnosed glioblastoma. However, in clinical practice, many centers continue TMZ maintenance therapy beyond six cycles. The impact of this continuation is controversial and has not yet been addressed in prospective randomized clinical trials. We compared the effect of more than six cycles of TMZ in comparison with exactly six cycles on overall survival (OS) and progression-free survival (PFS) by multivariate analysis and found a benefit in PFS but not OS. Thus, our data do not suggest prolonging TMZ maintenance therapy beyond six cycles, which should be considered in neurooncological practice.

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