Research AppraisalSystematic Review

A Narrative Review of Artificial Intelligence for Drug Repurposing: Lessons From COVID-19 and Oncology (2020-2025)

CPT: pharmacometrics & systems pharmacologyOgungbite, Alaba Bukola, Sibiya, Malusi1 July 2026DOI

Clinical Snapshot

5CEBM
Evidence: WeakSystematic Review

PICO Framework

P — PopulationNot formally defined — implicitly covers patients with COVID-19 or oncological conditions where drug repurposing strategies have been investigated; also encompasses the broader biomedical research and pharmaceutical pipeline context
I — InterventionArtificial intelligence (AI)-driven drug repurposing methodologies, including machine learning (ML), deep learning (DL), knowledge graphs (KGs), and natural language processing (NLP)
C — ComparatorNo formal comparator defined; implicitly contrasted with traditional drug discovery pipelines and non-AI-assisted repurposing approaches
O — OutcomesIdentification of drug-disease associations; methodological frameworks and technological innovations in AI-driven repurposing; challenges and future directions — no patient-centred clinical outcomes (e.g., mortality, response rates, adverse events) formally specified

Bottom Line

This narrative review provides a broad, accessible overview of AI methodologies applied to drug repurposing across COVID-19 and oncology from 2020 to 2025. It usefully catalogues the landscape of machine learning, deep learning, knowledge graph, and NLP approaches in this domain. However, as a piece of evidence-based medicine, it carries significant methodological limitations. The absence of a systematic search strategy, pre-specified inclusion criteria, quality appraisal of included studies, and quantitative synthesis means it cannot be considered a reliable evidence base for clinical or policy decision-making. The review conflates computational model performance with clinical efficacy — a critical distinction for practising clinicians. The enthusiastic framing around AI's 'transformative potential' is not adequately tempered by discussion of the substantial gap between in silico drug-disease association discovery and regulatory-grade clinical validation. For senior clinicians and health technology assessors, this paper is best read as a narrative orientation to the field rather than actionable evidence. Those seeking higher-quality synthesis should look to systematic reviews with PRISMA reporting and GRADE-assessed outcomes in this space.

Evidence: Weak

Key Findings

  • P Value: Not reported at the review level

  • Effect Size: Not applicable — no pooled effect size reported; individual study metrics referenced descriptively without standardised extraction

  • Primary Outcome: Narrative synthesis of AI methodologies (ML, DL, knowledge graphs, NLP) applied to drug repurposing in COVID-19 and oncology contexts; no primary quantitative outcome is defined or reported

  • Nnt Or Sensitivity: Not applicable — no NNT, sensitivity/specificity, or hazard ratio data synthesised; individual AI model performance metrics (e.g., AUC values from cited studies) are referenced narratively but not pooled or critically compared

  • Confidence Interval: Not reported — no meta-analytic synthesis performed

Clinical Application

The AI methodologies described (ML, DL, KGs, NLP) require substantial computational infrastructure, curated biomedical databases, and interdisciplinary expertise. Implementation in clinical or pharmaceutical settings is feasible at institutional level but not at the point of care. Regulatory validation pathways for AI-identified repurposed candidates remain underdeveloped globally In the Australian context, AI-driven drug repurposing intersects with TGA regulatory frameworks for new indications of registered medicines, PBS listing processes for repurposed agents, and NHMRC-funded translational research priorities. The MRFF (Medical Research Future Fund) has funded AI-in-health initiatives relevant to this space. For oncology specifically, the Therapeutic Goods Administration's provisional approval pathway and the PBS's managed entry schemes could theoretically accommodate AI-identified repurposed oncology agents, but no Australian-specific data or regulatory guidance is discussed in this review. RACGP guidelines do not currently address AI-assisted prescribing of repurposed medicines. The review's findings are relevant to Australian pharmaceutical researchers but offer no direct guidance for Australian prescribers or PBS formulary decisions. Broadly applicable as a conceptual overview for researchers and clinicians interested in computational drug repurposing methodology; not directly applicable to individual patient management decisions. Most relevant to pharmaceutical scientists, clinical trialists, and health technology assessment bodies evaluating AI-assisted drug development pipelines

Abstract

Drug repurposing presents a cost-effective and time-efficient strategy to identify new therapeutic applications for existing drugs. Recent advances in artificial intelligence, including machine learning, deep learning, knowledge graphs, and natural language processing, have revolutionized this field by enabling automated discovery of drug-disease associations. This review examines the role of artificial intelligence in drug repurposing, drawing insights from two critical case areas: Coronavirus disease 2019 and oncology. We explore current trends, methodological frameworks, and technological innovations in artificial intelligence-driven drug repurposing, as well as challenges and emerging future directions. The findings of this paper underscore the transformative potential of artificial intelligence in biomedical research and justify its continued integration in pharmaceutical pipelines.

References

  1. 1.Ogungbite, A. B., & Sibiya, M. (2025). A narrative review of artificial intelligence for drug repurposing: Lessons from COVID-19 and oncology (2020–2025). CPT: Pharmacometrics & Systems Pharmacology. https://doi.org/10.26434/chemrxiv-2025-f1hgn
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