1558 Background: The Epidermal Growth Factor Receptor (EGFR) gene is frequently amplified and mutated in high-grade gliomas. We are investigating the activity of the EGFR-targeted monoclonal antibody cetuximab for the treatment of patients (pts) with recurrent glioblastoma multiforme (GBM) following surgery, radiotherapy and chemotherapy.
METHODS
Adult pts with recurrent GBM are allocated to two parallel treatment strata according to the amplification status of the EGFR gene (determined by FISH). According to a Simon two-stage phase II study design 1 response in 13 pts/stratum is required to continue recruitment and complete the second stage of pt recruitment. Cetuximab is administered at 400 mg/m2 (2 hour infusion) day 1 and 250 mg/m2 day 8 and for all subsequent weekly doses (1 hour infusion).
RESULTS
Between May and December 2005, 17 pts were recruited (10 without EGFR-ampl, 4 with EGFR-ampl and 3 under investigation); 4F/13M; median age 51 years, range 32-67). Recruitment is ongoing. Sixteen pts initiated study treatment; 1 pt withdrew consent before the initiation of therapy. Treatment related toxicity in the first 94 treatment cycles consisted of grade 1/2 folliculitis/dermitis in all treated pts. Grade 3 adverse events consisted of thrombocytopenia (n=1 pt), diminished consciousness (n=1 pt), dizziness/confusion (n=1 pt), infectious bronchopneumonia (n=1 pt), and infectious cellulitis (n=1 pt). Thirteen pts have been evaluated for response ≤ week 8 of study treatment. Eleven pts had progression of disease. Two patients had SD at 8 weeks (follow-up is ongoing).
CONCLUSIONS
These preliminary data suggest that cetuximab can be safely administered to pretreated patients with recurrent GBM. Updated results regarding safety and activity as well as a correlative study of EGFR and PTEN expression and gene copy number of the GBM and response to cetuximab will be presented at the meeting. No significant financial relationships to disclose.