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ICCVAM Biennial Report 2018-2019

Biennial Progress Report 2018-2019 Interagency Coordinating Committee on the Validation of Alternative Methods

Open Structure-activity/property Relationship App (OPERA)

OPERA is a free and open-source/open-data suite of QSAR models providing predictions for physicochemical properties, environmental fate parameters, and toxicity endpoints. OPERA is an ongoing collaboration between NICEATM and EPA.

QSAR models provide predictions of chemical activity that can augment non-animal approaches for predicting toxicity. However, the performance of QSAR models highly depends on the quality of the data and modeling methodologies used. The EPA National Center for Computational Toxicology (now part of the EPA Center for Computational Toxicology and Exposure) created OPERA to provide robust QSAR models for chemical properties of environmental interest that can be used for regulatory purposes (Mansouri et al. 2018). 

Additions to OPERA during 2018-2019 include predictions for:

  • Estrogenic activity from CERAPP (Mansouri et al. 2016).
  • Androgenic activity from CoMPARA (Mansouri et al. 2020).
  • Acute oral systemic toxicity from CATMoS (Kleinstreuer et al. 2018).
  • Physicochemical properties such as acid dissociation constant (pKa) and octanol-water dissociation coefficient (logD) (Mansouri et al. 2019).
  • Properties such as human plasma fraction unbound and hepatic intrinsic clearance that affect how substances behave in biological systems, to support an open-source workflow for IVIVE.