A phase 1 trial of xentuzumab, an IGF-neutralizing antibody, in Japanese patients with advanced solid tumors

Cancer Sci. 2022 Mar;113(3):1010-1017. doi: 10.1111/cas.15231. Epub 2022 Jan 13.


Xentuzumab is an insulin-like growth factor (IGF) ligand-neutralizing antibody. This phase 1 trial assessed xentuzumab in Japanese patients with solid tumors. Patients aged ≥20 y old with solid tumors that were refractory or not amenable to standard therapy were enrolled. Patients received xentuzumab intravenously at a starting dose of 750 mg/wk. Dose escalation used a 3 + 3 design with dose de-escalation. The primary endpoint was to determine the maximum tolerated dose (MTD) of xentuzumab. Safety, pharmacokinetics, pharmacodynamics, and anti-tumor activity were also assessed. Fifteen patients received xentuzumab in the dose escalation part (750 mg/wk [n = 6]; 1000 mg/wk [n = 3]; 1400 mg/wk [n = 6]). There were no dose-limiting toxicities at any dose; the MTD of xentuzumab was not reached. Xentuzumab 1000 mg/wk was recommended as the relevant biological dose. Six further patients received xentuzumab 1000 mg/wk in an expansion cohort. Of 21 patients, 13 (61.9%) experienced a drug-related adverse event, most commonly fatigue (23.8%), neutropenia (19.0%), diarrhea, nausea, white blood cell count decrease, and muscle spasms (14.3% each). No relevant deviations from dose linearity of xentuzumab exposure were observed during dose escalation. Total IGF-1 and IGF-2 levels increased and bioactive IGF levels decreased from baseline to 24 h after the first infusion in cycle 1. Partial response was observed in 2 (9.5%) patients with desmoid-type fibromatosis. Disease control was achieved in 6 (28.6%) patients (median duration 42.4 mo). Xentuzumab monotherapy was well tolerated in Japanese patients and showed evidence of anti-tumor activity. This study was registered with www.clinicaltrials.gov (NCT02145741).

Keywords: Japanese; advanced tumors; insulin-like growth factor; monoclonal antibody; xentuzumab.

Publication types

  • Clinical Trial, Phase I

MeSH terms

  • Adult
  • Aged
  • Antibodies, Monoclonal, Humanized / pharmacokinetics
  • Antibodies, Monoclonal, Humanized / therapeutic use*
  • Antibodies, Neutralizing / immunology
  • Antibodies, Neutralizing / therapeutic use*
  • Dose-Response Relationship, Drug
  • Drug-Related Side Effects and Adverse Reactions
  • Female
  • Humans
  • Insulin-Like Growth Factor I / analysis
  • Insulin-Like Growth Factor I / immunology*
  • Insulin-Like Growth Factor II / analysis
  • Insulin-Like Growth Factor II / immunology*
  • Japan
  • Male
  • Maximum Tolerated Dose
  • Middle Aged
  • Neoplasms / drug therapy*
  • Neoplasms / pathology
  • Treatment Outcome


  • Antibodies, Monoclonal, Humanized
  • Antibodies, Neutralizing
  • IGF1 protein, human
  • IGF2 protein, human
  • Insulin-Like Growth Factor I
  • Insulin-Like Growth Factor II
  • xentuzumab

Associated data

  • ClinicalTrials.gov/NCT02145741

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