Bevacizumab and temozolomide versus temozolomide alone as neoadjuvant treatment in unresected glioblastoma: the GENOM 009 randomized phase II trial

Abstract

We sought to determine the impact of bevacizumab on reduction of tumor size prior to chemoradiotherapy in unresected glioblastoma patients. Patients were randomized 1:1 to receive temozolomide (TMZ arm) or temozolomide plus bevacizumab (TMZ + BEV arm). In both arms, neoadjuvant treatment was temozolomide (85 mg/m(2), days 1-21, two 28-day cycles), concurrent radiation plus temozolomide, and six cycles of adjuvant temozolomide. In the TMZ + BEV arm, bevacizumab (10 mg/kg) was added on days 1 and 15 of each neoadjuvant cycle and on days 1, 15 and 30 of concurrent treatment. The primary endpoint was investigator-assessed response to neoadjuvant treatment. Secondary endpoints included progression-free survival (PFS), overall survival (OS), and the impact on outcome of MGMT methylation in tumor and serum. One hundred and two patients were included; 43 in the TMZ arm and 44 in the TMZ + BEV arm were evaluable for response. Results favored the TMZ + BEV arm in terms of objective response (3 [6.7 %] vs. 11 [22.9 %]; odds ratio 4.2; P = 0.04). PFS and OS were longer in the TMZ + BEV arm, though the difference did not reach statistical significance. MGMT methylation in tumor, but not in serum, was associated with outcome. More patients experienced toxicities in the TMZ + BEV than in the TMZ arm (P = 0.06). The combination of bevacizumab plus temozolomide is more active than temozolomide alone and may well confer benefit in terms of tumor shrinkage in unresected patients albeit at the expense of greater toxicity.

Keywords: Bevacizumab; Glioblastoma; MGMT; Neoadjuvant; Serum MGMT; Temozolomide.