A first in man phase I trial of the oral immunomodulator, indoximod, combined with docetaxel in patients with metastatic solid tumors

// Hatem H. Soliman 1 , Erica Jackson 2 , Tony Neuger 1 , E. Claire Dees 3 , R. Donald Harvey 4 , Hyo Han 1 , Roohi Ismail-Khan 1 , Susan Minton 1 , Nicholas N. Vahanian 5 , Charles Link 5 , Daniel M. Sullivan 1 , Scott Antonia 1 1 H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 2 University of South Florida, Tampa, FL 3 University of North Carolina/Lineberger Cancer Center, Chapel Hill, NC 4 Winship Cancer Institute of Emory University, Atlanta, GA 5 NewLink Genetics Inc, Ames, IA Correspondence to: Dr. Hatem Soliman MD, e-mail: Hatem.soliman@moffitt.org Keywords: Indoximod, 1-methyl-D-tryptophan, immunomodulator, docetaxel, indoleamine 2, 3 dioxygenase Received: June 12, 2014      Accepted: August 16, 2014      Published: August 21, 2014 ABSTRACT Background: Indoleamine 2,3-dioxygenase (IDO) is an enzyme that tumors use to create a state of immunosuppression. Indoximod is an IDO pathway inhibitor. Preclinical studies demonstrated that indoximod combined with chemotherapy was synergistic in a mouse model of breast cancer. A phase I 3+3 trial was designed to study the combination of docetaxel and indoximod. Methods: Docetaxel was administered at 60 mg/m 2 intravenously every 3 weeks dose levels 1-4 and 75 mg/m 2 for dose level 5. Indoximod was given at 300, 600, 1000, 2000, and 1200 mg PO twice daily continuously for levels 1-5, respectively. Serum drug levels were measured. Results: Twenty-seven patients were treated, with 22 evaluable for response. DLTs included grade 3 dehydration (level 1), hypotension(level 4), mucositis (level 4) and grade 5 enterocolitis (level 2). Dose level 5 is the recommended phase II dose. The most frequent adverse events were fatigue (58.6%), anemia (51.7%), hyperglycemia (48.3%), infection (44.8%), and nausea (41.4%). There were 4 partial responses (2 breast, 1 NSCLC, 1 thymic tumor). No drug-drug interactions were noted. Conclusions: Docetaxel plus indoximod was well tolerated with no increase in expected toxicities or pharmacokinetic interactions. It was active in a pretreated population of patients with metastatic solid tumors.