Abstract
Abstract only
2030
Background: BEV is approved for use in recurrent glioblastoma. Patients (pts) who benefit from BEV therapy are often treated until tumor progression but fail to respond to salvage therapy suggesting that BEV may alter tumor biology. In a subset of pts who benefit from BEV, treatment is discontinued for reasons other than disease progression; the characteristics and outcomes of this subset are poorly defined. Methods: In this IRB approved retrospective study, our neuro-oncology longitudinal database was screened for pts treated with BEV for ≥ 6 months (mo) between 2005-2010 and 18 pts were identified in whom BEV was discontinued for reasons other than disease progression (BEV-D group). A cohort of 72 pts who received BEV until treatment failure due to progression was used as comparator (BEV-F group). Results: In the BEV-D group, 5 pts completed a planned treatment course and 13 stopped BEV due to toxicity; in this group, progression free survival at 12 mo (PFS12) was 83.3% (95% CI, 56.8-94.3) and median time to progression (TTP) 27.6 mo. Median TTP after BEV discontinuation was 7.0 mo. In contrast, in the BEV-F group, PFS12 was 24.6% (95% CI, 13.9-36.2) and median PFS 9.7 mo. Length of BEV therapy was not significantly different between the groups with a median time to discontinuation of 10.2 and 12 mo. In 12/18 pts in the BEV-D group who subsequently had tumor recurrence a predominantly local pattern of progression was seen unlike those in the BEV-F group who had more infiltrative or distant failures. Salvage therapy yielded a PFS-6 of 28.6% (95% CI, 4.1-61.2) with a median PFS of 17.1 wk compared with 6.8% (95% CI, 1.2-19.8) and 9 wk in the comparator group. Conclusions: Among pts who benefit from BEV therapy, the BEV-D group did not experience an immediate progression suggesting continued benefit after BEV cessation. This cohort also had a less invasive pattern of recurrence and a possibly improved response to salvage therapy compared with BEV-F group. Our results suggest that planned cessation of BEV therapy could potentially change patterns of progression and response to subsequent therapy. This strategy warrants further evaluation in prospective studies given the absence of effective salvage therapy after BEV failure.