Randomized phase IIb clinical trial of continuation or non-continuation with six cycles of temozolomide after the first six cycles of standard first-line treatment in patients with glioblastoma: A Spanish research group in neuro-oncology (GEINO) trial

2001 Background: The GEINO-14-01 trial (NCT02209948) investigated the role of extending temozolomide (TMZ) for 6 cycles after the standard 6 cycles to improve 6m-PFS, SLP and OS in newly diagnosed glioblastoma (GBM) patients (p). Methods: Between 08/2014 and 11/2018, 166 p were screened and 159 randomized to extend (80p) or not (79p) TMZ treatment for 6 cycles after proving stable disease in the MRI performed before inclusion. Centralized review of histology and determination of MGMT status, if not previously available, were performed before randomizing patients. Two criteria of stratification were used: MGMT status and presence/absence of residual disease on the basal MRI (defined as a residual enhancement larger than 1cm in one). The primary endpoint was differences in 6mPFS, secondary endpoints were differences in PFS, OS, toxicity, between arms and per stratification factors. Results: Median age was 60.3 (range 29-83), 97p (61%) were methylated, basal MRI showed residual disease in 57p (35.8%). After a median follow up of 14.0 months, with 121 p(76.1%) already progressed and 81p (50.9%) already dead, median PFS is presented. Median (m) PFS is 8.0 months (95%CI: 5.7-10.2). There is no difference in mPFS between arms (adjusted HR = 0.98, 95% CI: 0.82-1.18, P = 0.907). Methylated tumors had longer mPFS (HR=0.57, 95% CI: 0.39-0.83, P=0.004) irrespectively to the study treatment. Conclusions: There is not apparent benefit of continuing TMZ treatment for more than 6 cycles. Data will be actualized for the congress.Supported by a Grant of the ISCIII: PI13/01751. Clinical trial information: NCT02209948.