Interim data for ACT III: Phase II trial of PF-04948568 (CDX-110) in combination with temozolomide (TMZ) in patients (pts) with glioblastoma (GBM).

2014 Background: EGFRvIII is a constitutively activated mutation of EGFR, not expressed in normal tissues but expressed in GBM and other neoplasms. PF-04948568, a vaccine consisting of 13 amino acids unique to EGFRvIII, conjugated to keyhole limpet hemocyanin (KLH), has been coadministered intradermally with GM-CSF for the treatment of GBM. An initial single-arm phase II study conducted at Duke University and MDACC demonstrated tolerability and encouraging clinical activity. Subsequently a U.S., multicenter, randomized, open-label phase IIb/III study (ACT III) was initiated. Methods: Pts with gross total resection of newly diagnosed, EGFRvIII+ve GBM and successful completion of standard RT with concurrent TMZ, were eligible for enrollment. PF-04948568 was administered every other week x 3 prior to starting maintenance TMZ and monthly thereafter on day 21 of each TMZ cycle, until disease progression. Primary endpoint was progression-free rate (PFR) at 5.5 months from first vaccination. Results: 81 pts were...