{"doi":"10.1093/noajnl/vdaf259","title":"Pharmacokinetic-pharmacodynamic-efficacy modeling of the MDM2 inhibitor brigimadlin in glioblastoma patient-derived xenografts","abstract":"Abstract Background Murine double minute 2 (MDM2) inhibitors reactivate wild-type p53 and are a promising therapy for glioblastoma, IDH-wildtype (GBM). Brigimadlin is a highly potent MDM2 inhibitor being tested in a phase 0/1 clinical trial in combination with radiation in GBM. Methods Brigimadlin pharmacokinetics, pharmacodynamics, and efficacy were evaluated in GBM patient-derived xenografts (PDXs). Results In vitro, brigimadlin impaired viability in TP53 wild-type GBM with an IC50 of 0.8-6.6 nmol/L, but sensitivity did not correlate with MDM2 amplification. In vivo, MDM2 amplification was highly correlated with efficacy. In subcutaneous PDXs, 1 or 2 mg/kg brigimadlin dosed weekly was highly effective in 2 MDM2-amplified PDXs. At 2 mg/kg, brigimadlin delayed tumor regrowth by &amp;gt;5-fold in the MDM2-amplified PDXs compared to 1.5-fold in a non-amplified PDX. In orthotopic PDXs, efficacy was more limited, but 2 mg/kg brigimadlin enhanced the response to fractionated radiation in MDM2-amplified PDXs. Consistent with blood-brain barrier efflux limiting drug distribution, 2 mg/kg brigimadlin extended survival by &amp;gt;5-fold in an MDM2-amplified orthotopic PDX established in Rag1−/−Abcb1a−/− Abcg2−/− mice. In pharmacodynamic studies, p53 target genes were upregulated at both subtherapeutic and therapeutic dose levels, and the extent of activation did not correlate with MDM2 status. Concentrations of brigimadlin in tumor tissue were approximately 10-fold higher in MDM2-amplified tumors, and intracellular drug levels directly correlated with drug-dependent MDM2 upregulation, suggesting target binding affects drug accumulation. Conclusions Brigimadlin is highly effective in MDM2-amplified GBM when adequate drug levels are achieved in tumor tissue. MDM2 amplification impacts both treatment efficacy and intratumoral drug accumulation.","journal":"Neuro-Oncology Advances","year":2025,"id":585447,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9425,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":426323,"name":"Wenjuan Zhang","orcid":"0000-0001-6972-6449","position":1,"is_corresponding":false},{"id":1498800,"name":"Nishika Karbhari","orcid":"0000-0002-3360-6733","position":2,"is_corresponding":false},{"id":1099894,"name":"Ju-Hee Oh","orcid":null,"position":3,"is_corresponding":false},{"id":1099344,"name":"Katie L. 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