Computational repurposing of oncology drugs through off‐target drug binding interactions from pharmacological databases

Purpose Systematic repurposing of approved medicines for another indication may accelerate drug development in oncology. We present a strategy combining biomarker testing with drug repurposing to identify new treatments for patients with advanced cancer. Methods Tumours were sequenced with the Illumina TruSight Oncology 500 (TSO‐500) platform or the FoundationOne CDx panel. Mutations were screened by two medical oncologists and pathogenic mutations were categorised referencing literature. Variants of unknown significance were classified as potentially pathogenic using plausible mechanisms and computational prediction of pathogenicity. Gain of function (GOF) mutations were evaluated through repurposing databases Probe Miner (PM), Broad Institute Drug Repurposing Hub (Broad Institute DRH) and TOPOGRAPH. GOF mutations were repurposing events if identified in PM, not indexed in TOPOGRAPH and excluding mutations with a known Food and Drug Administration (FDA)‐approved biomarker. The computational repurposing approach was validated by evaluating its ability to identify FDA‐approved biomarkers. The total repurposable genome was identified by evaluating all possible gene‐FDA drug‐approved combinations in the PM dataset. Results The computational repurposing approach was accurate at identifying FDA therapies with known biomarkers (94%). Using next‐generation sequencing molecular reports (n = 94), a meaningful percentage of patients (14%) could have an off‐label therapeutic identified. The frequency of theoretical drug repurposing events in The Cancer Genome Atlas pan‐cancer dataset was 73% of the samples in the cohort. Conclusion A computational drug repurposing approach may assist in identifying novel repurposing events in cancer patients with no access to standard therapies. Further validation is needed to confirm a precision oncology approach using drug repurposing. Repurposing identified Food and Drug Administration‐approved drug‐biomarker combinations with high sensitivity and specificity. In a real‐world dataset, repurposing identified novel drug‐biomarker combinations in patients who were ineligible for standard therapies or biomarker‐matched trials. Preliminary functional validation was demonstrated for two drug‐biomarker combinations. Using The Cancer Genome Atlas data, the potential scope of repurposing was identified.