Leadscope Model Applier

Leadscope Model Applier (Leadscope, Inc.) is a chemoinformatic platform that provides QSAR models for the prediction of potential toxicity and adverse human clinical effects of pharmaceuticals, cosmetics, food ingredients and other chemicals. The models are constructed by FDA scientists based on both proprietary and non-proprietary data.

Leadscope models are developed with molecular descriptors that include structural features and phys-chem properties.

The prediction results for each model are provided as the “prediction call” and the “positive prediction probability”. The prediction call can be “positive”, “negative”, and “not-in-domain”. The positive prediction probability is given as the likelihood value between 0 (non-toxic) and 1 (toxic).

The higher the probability is, the greater chance there is of the test chemical being toxic in a particular endpoint.

Leadscope uses two parameters to guide the applicability of model domain:

  1. Model Features Count: parameter used to verify that the target compound contains a significant number of features that are present in the prediction model
  2. 30% Similarity Training Neighbours Count: number of training compounds structurally similar to the target (with at least 30 % similarity).

If at least one model feature and one training neighbour (> 30% similarity) are found, then the target is included in the applicability domain of the model. The robustness of the prediction can be further evaluated by examining compounds similar to the target from the training set.

Training set structural analogues are provided along with experimental and predicted data.