Clinical Review Abstract
Trials in Progress Abstract
Abstracts selected for publication but not presentation at the Annual Meeting
Abstracts granted an exception in accordance with ASCO's Conflict of Interest Policy
Response assessment of novoTTF-100A versus best physician’s choice chemotherapy in recurrent glioblastoma.
Central Nervous System Tumors
2013 ASCO Annual Meeting
J Clin Oncol 31, 2013 (suppl; abstr 2080)
Author(s): Eric Wong, Edwin Lok, Kenneth D. Swanson, Shiva Gautam, Herbert H. Engelhard, Frank S. Lieberman, Sophie Taillibert, Zvi Ram, John L. Villano, on behalf of the EF-11 Trial Investigators; Beth Israel Deaconess Medical Center, Boston, MA; University of Illinois at Chicago, Chicago, IL; University of Pittsburgh Cancer Institute, Pittsburgh, PA; Pitie-Salpetriere Hospital-Pierre et Marie Curie Paris VI University, Paris, France; Tel Aviv University, Tel Aviv, Israel; University of Kentucky, Lexington, KY
Background: The NovoTTF-100A device emits tumor treating electric fields and was tested against Best Physician’s Choice (BPC) chemotherapy in a randomized phase III trial. We analyzed post hoc the characteristics of responders and non-responders in both cohorts. Methods: Macdonald criteria were used to determine tumor response and progression. Kaplan-Meier and Chi-squared statistics were computed for time to response, response duration, progression-free survival (PFS) with and without Simon-Makuch correction, and overall survival (OS). Prognostic factors were compared using the Wilconox rank sum test. Relative hazard rates for responders and non-responders were plotted. Results: The median response duration was 7.3 versus 5.6 months for NovoTTF-100A and BPC chemotherapy respectively (p=0.0009). Five of 14 NovoTTF-100A responders but none of 7 BPC responders had prior low-grade histology. The mean cumulative dexamethasone dose was 35.9 mg for responders versus 485.6 mg for non-responders in the NovoTTF-100A cohort (p<0.0001) as compared to 525.6 mg for responders and 431.0 mg for non-responders in the BPC cohort (p=0.9520). Hazard rate analysis showed delayed tumor progression in responders compared to non-responders. The Simon-Makuch conditional plot, which adjusted for unequal progression-free states, still showed longer PFS in responders than non-responders treated with NovoTTF-100A (χ2=11.5, P=0.0007) or BPC chemotherapy (χ2=5.2, P=0.0222). The median OS was 24.8 months for responders that is longer than 6.2 months for non-responders treated with NovoTTF-100A (χ2=25.7, P<0.0001). In the BPC chemotherapy cohort, the median OS was 20.0 months for responders and 6.8 months for non-responders (χ2=5.1, P=0.0235). There was strong Pearson correlation between response and OS in NovoTTF-100A (P<0.0002) but not in BPC cohort (P=0.2952). Conclusions: Response duration, adjusted Simon-Makuch PFS and OS favor NovoTTF-100A over BPC chemotherapy. Data on prior low-grade histology and dexamethasone dose suggest potential genetic and epigenetic determinants of NovoTTF-100A response. Clinical trial information: NCT00379470.
Other Abstracts in this Sub-Category:
2. Bevacizumab, irinotecan, and radiotherapy versus standard temozolomide and radiotherapy in newly diagnosed, MGMT-nonmethylated glioblastoma patients: First results from the randomized multicenter GLARIUS trial.