rezatapopt (PC14586)

In this work, we show that missense mutant forms of p53, which occur in >60% of HGSOC, bind and inhibit ERα function and confer resistance to fulvestrant and elacestrant. Mechanistically, we show that mutant p53 predominantly inhibits one arm of the ERα pathway-the transactivation of jointly regulated ERα-SP1 target genes such as the mTOR regulator DEPTOR We show that silencing mutant p53 restores the ability of ERα to transactivate ERα-SP1 target genes and renders HGSOC markedly more sensitive to endocrine therapy. Consistent with this premise, we show that the p53 mutant Y220C refolding compound rezatapopt enhances fulvestrant response in a Y220C mutant cell line.

P1/2, N=300, Recruiting, PMV Pharmaceuticals, Inc | N=230 --> 300 | Trial completion date: Jul 2026 --> Dec 2027 | Trial primary completion date: Mar 2026 --> Aug 2026

NCT04585750 (ClinicalTrials.gov).

Rezatapopt is an investigational small molecule p53 reactivator that binds specifically to the Y220C-mutant p53 protein without interacting with wild-type or other mutant p53 proteins...There are several wild type Tp53 regulated pathways that could play a role in reversing the inflammatory response and tumor growth observed in this patient case. This perspective explores the signal transduction pathways involved in this cancer mediated inflammation and the extensive reduction of detectable tumor tissue.

Pharmacological inhibition of the BCL-2/BAX interaction with venetoclax fully compensates for this deficiency, induces massive cell death in AML cells and stem/progenitor cells in vitro and prolongs survival of TP53-Y220C AML xenografts in vivo. Collectively, we identified transcription-dependent and -independent mechanisms that limit the apoptogenic activities of reactivated conformational p53-WT and suggest approaches to optimize apoptosis induction in TP53-mutant leukemia. A clinical trial of PC14586 in TP53-Y220C AML/myelodysplastic syndromes has recently been initiated (NCT06616636).

achieve to enhance our understanding of the mechanisms and effects of p53-Y220C reactivator compounds and underscore the potential of targeting p53 mutants in cancer therapy [3]. Through this spotlight article, we aim to summarize the findings and emphasize the clinical implications of the study by Puzio-Kutler et al.

These compounds demonstrate potent anti-tumor activity in preclinical models as single agents and in combination with immunotherapy. Currently, rezatapopt is being evaluated in a registrational Phase 2 clinical trial for patients with advanced solid tumors harboring the TP53 Y220C mutation.

P1, N=24, Recruiting, M.D. Anderson Cancer Center | Not yet recruiting --> Recruiting

In mouse models with established human tumor xenografts harboring the TP53 Y220C mutation, rezatapopt demonstrated tumor inhibition and regression at well-tolerated doses. In Phase 1 clinical trials, rezatapopt demonstrated a favorable safety profile within the efficacious dose range and showed single-agent efficacy in heavily pretreated patients with various TP53 Y220C mutant solid tumors.

P1, N=28, Completed, PMV Pharmaceuticals, Inc | Active, not recruiting --> Completed | Trial completion date: Jun 2024 --> Feb 2024

P1, N=12, Completed, PMV Pharmaceuticals, Inc | Recruiting --> Completed

P1, N=25, Not yet recruiting, M.D. Anderson Cancer Center