Background Pts with glioblastoma (GBM; WHO grade IV) have a poor prognosis. Epidermal growth factor receptor amplification (EGFR amp) is present in ~50% of GBM, resultinginauniqueprotein conformation ofEGFRthatcanbetargetedbyan antibody-drug conjugate, ABT-414. ABT-414 is comprised ofan antibody, ABT-806, which targets EGFR amp, and a toxin, monomethyl auristatin F (MMAF). ABT-414 is internalized by tumor cells and MMAF is released, resulting in cell death. Here we reporttolerabilityandPKofABT-414aloneandwithradiationtherapy(RT) and temozolomide (TMZ) in Japanese pts. Methods Study M13-714 (NCT02590263) is a non-randomized, open-label, Phase 1/2 studyinJapanesepts. Phase1, Arm AevaluatestolerabilityandPK ofABT-414 onlyin WHO grade III-IV recurrent glioma (rGBM); Arm B evaluates ABT-414 + RT/TMZ in newlydiagnosed pts. Phase 2 assesses efficacy ofABT-414 + TMZ in EGFR amp, rGBM. Presented here are Phase 1, Arm A results (3 + 3 dose escalation; 0.5-1.25 mg/kg, i.v. every2 weeks), andpreliminaryPhase1, Arm Bresults. Results As of June 13, 2016, 10 pts were enrolled. Arm A, n = 9 pts at 3 doses: 0.5 mg/kg (n = 3); 1.0 mg/kg (n = 3); 1.25 mg/kg (n = 3). Arm B, n = 1 pt at 1.0 mg/kg + RT/TMZ. In Arm A, 6 pts were screened for EGFR amp; 2/6 (33%) were positive. The most common treatment emergent adverse events (TEAEs, > 1 pt) were ocular-related, keratopathy(4/10, 40%) asmostprevalent. OtherTEAEswereincreasedALT/AST levels(4/10, 40% each) anddecreasedplateletcountandcornealinjury(2/10, 20% each). The most common Grade 3/4 TEAEs were corneal erosion, keratitis, decreased platelets and malignant neoplasm progression (1 pt, 10% each). Four pts had stable disease (SD), with 1 pt (EGFR+) maintaining SD for 40 weeks. Preliminary PK analysis forABT-414 andABT-806wasdoneon7pts(0.5mg/kg,n= 2;1.0mg/kg, n=3; 25mg/kg, n=2), andforcys-mcMMAF on 5pts (0.5mg/kg, n=2; 1.0mg/kg, n=3). Cmax(maximumserumconcentration) andAUC14day(areaunderthecurve, drug concentration vs time) were approximately dose-proportional for ABT-414 and cys- mcMMAF. Conclusions:ABT-414 displayedacceptabletolerabilityandPKprofileinJapanesepts, suggestingthatitmaybeanoveltherapyforthoseinneedofbettertreatments. Clinical trial indentification NCT02590263 Legal entity responsible for the study AbbVie, Inc. Funding AbbVie, Inc. Disclosure Y. Narita: Honoraria (lecture fees) from Chugai Pharmaceutical Co., MSD; research funding from Nihon Medi-Physics Co. and AbbVie GK. M. Nagane: Honoraria: Chugai, MSD KK, Eisai, Otsuka, Novartis, Ono, Bayer Schering, Nobelpharma, AbbVie, Novocure. Research funding: Daiichi Sankyo, Chugai, MSD KK, Eisai, Kyowa Hakko Kirin, AbbVie, Ono, Mitsubishi Tanabe, Pfizer. Gifts: Daiichi- Sankyo, AbbVie GK. T. Wakabayashi: Contributions from Pfizer. T. Hamada, R. Odagawa, Y. Nishimura, T. Kiriyama, H. Xiong, C. Ocampo: Employee ofAbbVie and may own stock. R. Nishikawa: Honoraria from Chugai Pharmaceutical Co., MSD, Eisai, Novocure and AbbVie. All other authors have declared no conflicts ofinterest.