DeepAS - Chemical language model for the extension of active analogue series

Extension of multi-site analogue series with potent compounds using a bidirectional transformer-based chemical language model

Generating potent compounds for evolving analogue series (AS) is a key challenge in medicinal chemistry. The versatility of chemical language models (CLMs) makes it possible to formulate this challenge as an off-the-beaten-path prediction task. In this work, we have devised a coding and tokenization scheme for evolving AS with multiple substitution sites (multi-site AS) and implemented a bidirectional transformer to predict new potent analogues for such series. Scientific foundations of this approach are discussed and, as a benchmark, the transformer model is compared to a recurrent neural network (RNN) for the prediction of analogues of AS with single substitution sites. Furthermore, the transformer is shown to successfully predict potent analogues with varying R-group combinations for multi-site AS having activity against many different targets. Prediction of R-group combinations for extending AS with potent compounds represents a novel approach for compound optimization.

Chemical language models for molecular design

In drug discovery, chemical language models (CLMs) originating from natural language processing offer new opportunities for molecular design. CLMs have been developed using recurrent neural network (RNN) or transformer architectures. For the predictive performance of RNN-based encoder-decoder frameworks and transformers, attention mechanisms play a central role. Among others, emerging application areas for CLMs include constrained generative modeling and the prediction of chemical reactions or drug-target interactions. Since CLMs are applicable to any compound or target data that can be presented in a sequential format and tokenized, mappings of different types of sequences can be learned. For example, active compounds can be predicted from protein sequence motifs. Novel off-the-beat-path applications can also be considered. For example, analogue series from medicinal chemistry can be perceived and represented as chemical sequences and extended with new compounds using CLMs. Herein, methodological features of CLMs and different applications are discussed.