Linsitinib (OSI-906) for the Treatment of Adult and Pediatric Wild-Type Gastrointestinal Stromal Tumors, a SARC Phase II Study

Clin Cancer Res. 2020 Apr 15;26(8):1837-1845. doi: 10.1158/1078-0432.CCR-19-1069. Epub 2019 Dec 2.


Purpose: Most gastrointestinal stromal tumors (GIST) have activating mutations of KIT, PDGFRA, or uncommonly BRAF. Fifteen percent of adult and 85% of pediatric GISTs are wild type (WT), commonly having high expression of IGF-1R and loss of succinate dehydrogenase (SDH) complex function. We tested the efficacy of linsitinib, an oral TKI IGF-1R inhibitor, in patients with WT GIST.

Patients and methods: A multicenter phase II trial of linsitinib was conducted. The primary endpoint was objective response rate. Secondary endpoints were clinical benefit rate: complete response, partial response, and stable disease (SD) ≥ 9 months, and quantitative 2[18F]fluoro-2-deoxy-D-glucose (FDG) metabolic response (MR) at week 8. Serum levels for glucose, insulin, IGF-1R ligand IGF1, and binding proteins were obtained to explore correlations to patient outcomes and FDG-PET results.

Results: Twenty patients were accrued in a 6-month period. Grade 3-4 toxicities possibly related to linsitinib were uncommon (8.5%). No objective responses were seen. Clinical benefit rate (CBR) at 9 months was 40%. Intense FDG uptake was observed at baseline, with partial MR of 12% and stable metabolic disease of 65% at week 8; these patients had RECIST 1.1 SD as their best response. Progression-free survival (PFS) and overall survival Kaplan-Meier estimates at 9 months were 52% and 80%, respectively. SDHA/B loss determined by IHC was seen in 35% and 88% of cases, respectively.

Conclusions: Linsitinib is well tolerated in patients with WT GIST. Although the 9-month CBR was 40%, and PFS at 9 months was 52%, no objective responses were observed. Rapid accrual to this study demonstrates that clinical trials of experimental agents in selected subtypes of GIST are feasible.

Publication types

  • Clinical Trial, Phase II
  • Multicenter Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Electron Transport Complex II / genetics
  • Female
  • Gastrointestinal Neoplasms / drug therapy*
  • Gastrointestinal Neoplasms / genetics
  • Gastrointestinal Neoplasms / pathology
  • Gastrointestinal Stromal Tumors / drug therapy*
  • Gastrointestinal Stromal Tumors / genetics
  • Gastrointestinal Stromal Tumors / pathology
  • Humans
  • Imidazoles / therapeutic use*
  • Male
  • Middle Aged
  • Mutation*
  • Patient Safety
  • Protein Kinase Inhibitors / therapeutic use*
  • Proto-Oncogene Proteins c-kit / genetics
  • Pyrazines / therapeutic use*
  • Receptor, IGF Type 1 / antagonists & inhibitors*
  • Receptor, IGF Type 1 / metabolism
  • Treatment Outcome
  • Young Adult


  • 3-(8-amino-1-(2-phenylquinolin-7-yl)imidazo(1,5-a)pyrazin-3-yl)-1-methylcyclobutanol
  • IGF1R protein, human
  • Imidazoles
  • Protein Kinase Inhibitors
  • Pyrazines
  • Electron Transport Complex II
  • SDHA protein, human
  • KIT protein, human
  • Proto-Oncogene Proteins c-kit
  • Receptor, IGF Type 1