Emmanuel Bengio

GFlowNet Pretraining with Inexpensive Rewards

Mohit Pandey

Gopeshh Subbaraj

Generative Flow Networks (GFlowNets), a class of generative models have recently emerged as a suitable framework for generating diverse and … (voir plus)high-quality molecular structures by learning from unnormalized reward distributions. Previous works in this direction often restrict exploration by using predefined molecular fragments as building blocks, limiting the chemical space that can be accessed. In this work, we introduce Atomic GFlowNets (A-GFNs), a foundational generative model leveraging individual atoms as building blocks to explore drug-like chemical space more comprehensively. We propose an unsupervised pre-training approach using offline drug-like molecule datasets, which conditions A-GFNs on inexpensive yet informative molecular descriptors such as drug-likeliness, topological polar surface area, and synthetic accessibility scores. These properties serve as proxy rewards, guiding A-GFNs towards regions of chemical space that exhibit desirable pharmacological properties. We further our method by implementing a goal-conditioned fine-tuning process, which adapts A-GFNs to optimize for specific target properties. In this work, we pretrain A-GFN on the ZINC15 offline dataset and employ robust evaluation metrics to show the effectiveness of our approach when compared to other relevant baseline methods in drug design.

2024-09-14

ArXiv (prépublication)

arxiv.org

Learning to Scale Logits for Temperature-Conditional GFlowNets

Joohwan Ko

Woo Chang Kim

Jinkyoo Park

GFlowNets are probabilistic models that sequentially generate compositional structures through a stochastic policy. Among GFlowNets, tempera… (voir plus)ture-conditional GFlowNets can introduce temperature-based controllability for exploration and exploitation. We propose \textit{Logit-scaling GFlowNets} (Logit-GFN), a novel architectural design that greatly accelerates the training of temperature-conditional GFlowNets. It is based on the idea that previously proposed approaches introduced numerical challenges in the deep network training, since different temperatures may give rise to very different gradient profiles as well as magnitudes of the policy's logits. We find that the challenge is greatly reduced if a learned function of the temperature is used to scale the policy's logits directly. Also, using Logit-GFN, GFlowNets can be improved by having better generalization capabilities in offline learning and mode discovery capabilities in online learning, which is empirically verified in various biological and chemical tasks. Our code is available at https://github.com/dbsxodud-11/logit-gfn

2024-04-30

ICML.cc/2024/Conference (poster)

proceedings.mlr.press

Generative Active Learning for the Search of Small-Molecule Protein Binders

Maksym Korablyov

Cheng-Hao Liu

Moksh Jain

Almer Van Der Sloot

Éric Jolicoeur

Edward Ruediger

Andrei Nica

Kostiantyn Lapchevskyi

Daniel St-Cyr

Doris Alexandra Schuetz

Victor Ion Butoi

Saikrishna Gottipati

Prateek Gupta

Ladislav Rampasek … (voir 14 de plus)

Sasikanth Avancha

Pierre-Luc Bacon

William Hamilton

Brooks Paige

Sanchit Misra

Stanislaw Jastrzebski

Bharat Kaul

Doina Precup

José Miguel Hernández-Lobato

Marwin Segler

Michael Bronstein

Anne Marinier

Mike Tyers

Despite substantial progress in machine learning for scientific discovery in recent years, truly de novo design of small molecules which exh… (voir plus)ibit a property of interest remains a significant challenge. We introduce LambdaZero, a generative active learning approach to search for synthesizable molecules. Powered by deep reinforcement learning, LambdaZero learns to search over the vast space of molecules to discover candidates with a desired property. We apply LambdaZero with molecular docking to design novel small molecules that inhibit the enzyme soluble Epoxide Hydrolase 2 (sEH), while enforcing constraints on synthesizability and drug-likeliness. LambdaZero provides an exponential speedup in terms of the number of calls to the expensive molecular docking oracle, and LambdaZero de novo designed molecules reach docking scores that would otherwise require the virtual screening of a hundred billion molecules. Importantly, LambdaZero discovers novel scaffolds of synthesizable, drug-like inhibitors for sEH. In in vitro experimental validation, a series of ligands from a generated quinazoline-based scaffold were synthesized, and the lead inhibitor N-(4,6-di(pyrrolidin-1-yl)quinazolin-2-yl)-N-methylbenzamide (UM0152893) displayed sub-micromolar enzyme inhibition of sEH.

2023-12-31

arXiv (prépublication)

arxiv.org

Local Search GFlowNets

Sungsoo Ahn

Jinkyoo Park

Generative Flow Networks (GFlowNets) are amortized sampling methods that learn a distribution over discrete objects proportional to their re… (voir plus)wards. GFlowNets exhibit a remarkable ability to generate diverse samples, yet occasionally struggle to consistently produce samples with high rewards due to over-exploration on wide sample space. This paper proposes to train GFlowNets with local search, which focuses on exploiting high-rewarded sample space to resolve this issue. Our main idea is to explore the local neighborhood via backtracking and reconstruction guided by backward and forward policies, respectively. This allows biasing the samples toward high-reward solutions, which is not possible for a typical GFlowNet solution generation scheme, which uses the forward policy to generate the solution from scratch. Extensive experiments demonstrate a remarkable performance improvement in several biochemical tasks. Source code is available: https://github.com/dbsxodud-11/ls_gfn.

2023-12-31

ICLR (publié)

Maximum entropy GFlowNets with soft Q-learning

Sobhan Mohammadpour

Emma Frejinger

Pierre-Luc Bacon

Generative Flow Networks (GFNs) have emerged as a powerful tool for sampling discrete objects from unnormalized distributions, offering a sc… (voir plus)alable alternative to Markov Chain Monte Carlo (MCMC) methods. While GFNs draw inspiration from maximum entropy reinforcement learning (RL), the connection between the two has largely been unclear and seemingly applicable only in specific cases. This paper addresses the connection by constructing an appropriate reward function, thereby establishing an exact relationship between GFNs and maximum entropy RL. This construction allows us to introduce maximum entropy GFNs, which, in contrast to GFNs with uniform backward policy, achieve the maximum entropy attainable by GFNs without constraints on the state space.

2023-12-31

AISTATS (publié)

proceedings.mlr.press

SynFlowNet: Design of Diverse and Novel Molecules with Synthesis Constraints

M. Cretu

Charles Harris

Julien Roy

Pietro Lio’

Generative models see increasing use in computer-aided drug design. However, while performing well at capturing distributions of molecular m… (voir plus)otifs, they often produce synthetically inaccessible molecules. To address this, we introduce SynFlowNet, a GFlowNet model whose action space uses chemical reactions and buyable reactants to sequentially build new molecules. By incorporating forward synthesis as an explicit constraint of the generative mechanism, we aim at bridging the gap between in silico molecular generation and real world synthesis capabilities. We evaluate our approach using synthetic accessibility scores and an independent retrosynthesis tool to assess the synthesizability of our compounds, and motivate the choice of GFlowNets through considerable improvement in sample diversity compared to baselines. Additionally, we identify challenges with reaction encodings that can complicate traversal of the MDP in the backward direction. To address this, we introduce various strategies for learning the GFlowNet backward policy and thus demonstrate how additional constraints can be integrated into the GFlowNet MDP framework. This approach enables our model to successfully identify synthesis pathways for previously unseen molecules.

2023-12-31

arXiv.org (prépublication)

arxiv.org

A community effort in SARS-CoV-2 drug discovery.

Johannes Schimunek

Philipp Seidl

Katarina Elez

Tim Hempel

Tuan Le

Frank Noé

Simon Olsson

Lluís Raich

Robin Winter

Hatice Gokcan

Filipp Gusev

Evgeny M. Gutkin

Olexandr Isayev

Maria G. Kurnikova

Chamali H. Narangoda

Roman Zubatyuk

Ivan P. Bosko

Konstantin V. Furs

Anna D. Karpenko

Yury V. Kornoushenko … (voir 133 de plus)

Mikita Shuldau

Artsemi Yushkevich

Mohammed B. Benabderrahmane

Patrick Bousquet‐Melou

Ronan Bureau

Beatrice Charton

Bertrand C. Cirou

Gérard Gil

William J. Allen

Suman Sirimulla

Stanley Watowich

Nick Antonopoulos

Nikolaos Epitropakis

Agamemnon Krasoulis

Vassilis Pitsikalis

Stavros Theodorakis

Igor Kozlovskii

Anton Maliutin

Alexander Medvedev

Petr Popov

Mark Zaretckii

Hamid Eghbal‐Zadeh

Christina Halmich

Sepp Hochreiter

Andreas Mayr

Peter Ruch

Michael Widrich

Francois Berenger

Ashutosh Kumar

Yoshihiro Yamanishi

Kam Y. J. Zhang

Moksh J. Jain

Maksym Korablyov

Cheng-Hao Liu

Gilles Marcou

M. Gilles

Enrico Glaab

Kelly Barnsley

Suhasini M. Iyengar

Mary Jo Ondrechen

V. Joachim Haupt

Florian Kaiser

Michael Schroeder

Luisa Pugliese

Simone Albani

Christina Athanasiou

Andrea Beccari

Paolo Carloni

Giulia D'Arrigo

Eleonora Gianquinto

Jonas Goßen

Anton Hanke

Benjamin P. Joseph

Daria B. Kokh

Sandra Kovachka

Candida Manelfi

Goutam Mukherjee

Abraham Muñiz‐Chicharro

Francesco Musiani

Ariane Nunes‐Alves

Giulia Paiardi

Giulia Rossetti

S. Kashif Sadiq

Francesca Spyrakis

Carmine Talarico

Alexandros Tsengenes

Rebecca C. Wade

Conner Copeland

Jeremiah Gaiser

Daniel R. Olson

Amitava Roy

Vishwesh Venkatraman

Travis J. Wheeler

Haribabu Arthanari

Klara Blaschitz

Marco Cespugli

Vedat Durmaz

Konstantin Fackeldey

Patrick D. Fischer

Christoph Gorgulla

Christian Gruber

Karl Gruber

Michael Hetmann

Jamie E. Kinney

Krishna M. Padmanabha Das

Shreya Pandita

Amit Singh

Georg Steinkellner

Guilhem Tesseyre

Gerhard Wagner

Zi‐Fu Wang

Ryan J. Yust

Dmitry S. Druzhilovskiy

Dmitry A. Filimonov

Pavel V. Pogodin

Vladimir Poroikov

Anastassia V. Rudik

Leonid A. Stolbov

Alexander V. Veselovsky

Maria De Rosa

Giada De Simone

Maria R. Gulotta

Jessica Lombino

Nedra Mekni

Ugo Perricone

Arturo Casini

Amanda Embree

D. Benjamin Gordon

David Lei

Katelin Pratt

Christopher A. Voigt

Kuang‐Yu Chen

Yves Jacob

Tim Krischuns

Pierre Lafaye

Agnès Zettor

M. Luis Rodríguez

Kris M. White

Daren Fearon

Frank Von Delft

Martin A. Walsh

Dragos Horvath

Charles L. Brooks

Babak Falsafi

Bryan Ford

Adolfo García‐Sastre

Sang Yup Lee

Nadia Naffakh

Alexandre Varnek

Günter Klambauer

Thomas M. Hermans

The COVID-19 pandemic continues to pose a substantial threat to human lives and is likely to do so for years to come. Despite the availabili… (voir plus)ty of vaccines, searching for efficient small-molecule drugs that are widely available, including in low- and middle-income countries, is an ongoing challenge. In this work, we report the results of an open science community effort, the "Billion molecules against Covid-19 challenge", to identify small-molecule inhibitors against SARS-CoV-2 or relevant human receptors. Participating teams used a wide variety of computational methods to screen a minimum of 1 billion virtual molecules against 6 protein targets. Overall, 31 teams participated, and they suggested a total of 639,024 molecules, which were subsequently ranked to find 'consensus compounds'. The organizing team coordinated with various contract research organizations (CROs) and collaborating institutions to synthesize and test 878 compounds for biological activity against proteases (Nsp5, Nsp3, TMPRSS2), nucleocapsid N, RdRP (only the Nsp12 domain), and (alpha) spike protein S. Overall, 27 compounds with weak inhibition/binding were experimentally identified by binding-, cleavage-, and/or viral suppression assays and are presented here. Open science approaches such as the one presented here contribute to the knowledge base of future drug discovery efforts in finding better SARS-CoV-2 treatments.

2023-11-13

Molecular informatics (publié)

Baking Symmetry into GFlowNets

George Ma

Dinghuai Zhang

GFlowNets have exhibited promising performance in generating diverse candidates with high rewards. These networks generate objects increment… (voir plus)ally and aim to learn a policy that assigns probability of sampling objects in proportion to rewards. However, the current training pipelines of GFlowNets do not consider the presence of isomorphic actions, which are actions resulting in symmetric or isomorphic states. This lack of symmetry increases the amount of samples required for training GFlowNets and can result in inefficient and potentially incorrect flow functions. As a consequence, the reward and diversity of the generated objects decrease. In this study, our objective is to integrate symmetries into GFlowNets by identifying equivalent actions during the generation process. Experimental results using synthetic data demonstrate the promising performance of our proposed approaches.

2023-10-26

NeurIPS.cc/2023/Workshop/AI4Science (présentation orale)

DGFN: Double Generative Flow Networks

2023-10-26

NeurIPS.cc/2023/Workshop/GenBio (poster)

Multi-Objective GFlowNets

Moksh Jain

Sharath Chandra Raparthy

Alex Hernandez-Garcia

Jarrid Rector-Brooks

Santiago Miret

We study the problem of generating diverse candidates in the context of Multi-Objective Optimization. In many applications of machine learni… (voir plus)ng such as drug discovery and material design, the goal is to generate candidates which simultaneously optimize a set of potentially conflicting objectives. Moreover, these objectives are often imperfect evaluations of some underlying property of interest, making it important to generate diverse candidates to have multiple options for expensive downstream evaluations. We propose Multi-Objective GFlowNets (MOGFNs), a novel method for generating diverse Pareto optimal solutions, based on GFlowNets. We introduce two variants of MOGFNs: MOGFN-PC, which models a family of independent sub-problems defined by a scalarization function, with reward-conditional GFlowNets, and MOGFN-AL, which solves a sequence of sub-problems defined by an acquisition function in an active learning loop. Our experiments on wide variety of synthetic and benchmark tasks demonstrate advantages of the proposed methods in terms of the Pareto performance and importantly, improved candidate diversity, which is the main contribution of this work.

2023-07-02

Proceedings of the 40th International Conference on Machine Learning (publié)

proceedings.mlr.press

Goal-conditioned GFlowNets for Controllable Multi-Objective Molecular Design

Julien Roy

Pierre-Luc Bacon

Christopher Pal

In recent years, in-silico molecular design has received much attention from the machine learning community. When designing a new compound f… (voir plus)or pharmaceutical applications, there are usually multiple properties of such molecules that need to be optimised: binding energy to the target, synthesizability, toxicity, EC50, and so on. While previous approaches have employed a scalarization scheme to turn the multi-objective problem into a preference-conditioned single objective, it has been established that this kind of reduction may produce solutions that tend to slide towards the extreme points of the objective space when presented with a problem that exhibits a concave Pareto front. In this work we experiment with an alternative formulation of goal-conditioned molecular generation to obtain a more controllable conditional model that can uniformly explore solutions along the entire Pareto front.

2023-06-22

ICML.cc/2023/Workshop/DeployableGenerativeAI (publié)