Combination of the mTOR inhibitor ridaforolimus and the anti-IGF1R monoclonal antibody dalotuzumab: preclinical characterization and phase I clinical trial
Serena Di Cosimo, Sriram Sathyanarayanan, Johanna C Bendell, Andrés Cervantes, Mark N Stein, Irene Braña, Desamparados Roda, Brian B Haines, Theresa Zhang, Christopher G Winter, Sharda Jha, Youyuan Xu, Jason Frazier, Richard A Klinghoffer, Ann Leighton-Swayze, Yang Song, Scot Ebbinghaus, José Baselga, Serena Di Cosimo, Sriram Sathyanarayanan, Johanna C Bendell, Andrés Cervantes, Mark N Stein, Irene Braña, Desamparados Roda, Brian B Haines, Theresa Zhang, Christopher G Winter, Sharda Jha, Youyuan Xu, Jason Frazier, Richard A Klinghoffer, Ann Leighton-Swayze, Yang Song, Scot Ebbinghaus, José Baselga
Abstract
Purpose: Mammalian target of rapamycin (mTOR) inhibition activates compensatory insulin-like growth factor receptor (IGFR) signaling. We evaluated the ridaforolimus (mTOR inhibitor) and dalotuzumab (anti-IGF1R antibody) combination.
Experimental design: In vitro and in vivo models, and a phase I study in which patients with advanced cancer received ridaforolimus (10-40 mg/day every day × 5/week) and dalotuzumab (10 mg/kg/week or 7.5 mg/kg/every other week) were explored.
Results: Preclinical studies demonstrated enhanced pathway inhibition with ridaforolimus and dalotuzumab. With 87 patients treated in the phase I study, main dose-limiting toxicities (DLT) of the combination were primarily mTOR-related stomatitis and asthenia at doses of ridaforolimus lower than expected, suggesting blockade of compensatory pathways in normal tissues. Six confirmed partial responses were reported (3 patients with breast cancer); 10 of 23 patients with breast cancer and 6 of 11 patients with ER(+)/high-proliferative breast cancer showed antitumor activity.
Conclusions: Our study provides proof-of-concept that inhibiting the IGF1R compensatory response to mTOR inhibition is feasible with promising clinical activity in heavily pretreated advanced cancer, particularly in ER(+)/high-proliferative breast cancer (ClinicalTrials.gov identifier: NCT00730379).
Conflict of interest statement
Disclosure of Potential Conflicts of Interest
B.B. Haines, S. Jha, Y. Song, Y. Xu, and T. Zhang are employees of Merck & Co., Inc. S. Ebbinghaus, S. Sathyanarayanan, andA. Leighton-Swayze are employees of and have ownership interest in Merck & Co., Inc. J. Frazier was an employee of and has ownership interest in Merck and Co. R.A. Klinghoffer and C.G. Winter were employees of Merck & Co., Inc. S. Ebbinghaus, R.A. Klinghoffer, S. Sathyanarayanan, and C.G. Winter are listed on a patent application for ridaforolimus owned by Merck & Co., Inc. No other potential conflicts of interest were disclosed by the other authors.
©2014 American Association for Cancer Research.
Figures
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Source: PubMed