# Extend p53 reactivation beyond the Y220C mutation

Source: https://onco.cc/ideas/idea-bio1-p53-mutant-reactivator-expansion/  
OnCo record `idea-bio1-p53-mutant-reactivator-expansion` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

One faulty version of the p53 guardian protein can now be repaired by a drug that plugs a hole in it. Systematically hunting for similar holes in other faulty versions could help far more patients.

## Summary

Rezatapopt (PC14586) binds a crevice created by the TP53 Y220C mutation and restores wild-type folding, with responses reported in early trials. Y220C is only around 1 percent of TP53 mutations. A systematic structural and covalent-fragment campaign across the ten commonest TP53 hotspots (R175H, R248Q, R273H, R282W and others), using cryo-EM, deep mutational scanning and AI structure prediction of mutant conformational ensembles, could find analogous pockets or cysteine-reactive sites.

## Fields

- Kind: Idea
- Last checked: 2026-09-08
- Hypothesis: At least two additional TP53 hotspot mutants have a reproducible small-molecule-stabilisable conformation that restores p53 transcriptional activity in cells by more than 50 percent of wild-type.
- Rationale: TP53 is mutated in about half of all cancers; a mutation-specific reactivator strategy is now clinically validated in principle, and the chemistry (covalent stabilisers, chaperone-like binders) is transferable.
- Proposed test: A three-year structure-first campaign with a public compound and structure release; cell-based p53 reporter and transcriptomic restoration assays as the go/no-go for each hotspot.
- Maturity: early-clinical
- Actor: research

## Sources

- Bottleneck evidence (The undruggable drivers): Dang et al., Drugging the 'undruggable' cancer targets (Nature Reviews Cancer 2017): https://doi.org/10.1038/nrc.2017.36

## Connected records

- technologies: [AI-driven drug & target discovery](https://onco.cc/technologies/ai-drug-design/)
- targets: [TP53](https://onco.cc/targets/tp53/)
- pathways: [p53 / RB / cell-cycle checkpoint](https://onco.cc/pathways/p53-cell-cycle/)
- bottlenecks: [The undruggable drivers](https://onco.cc/bottlenecks/b-undruggable-targets/)
- key papers: [Drugging the 'undruggable' cancer targets](https://onco.cc/key-papers/paper-dang-nat-rev-cancer/), [Vogelstein, Lane and Levine 2000: surfing the p53 network](https://onco.cc/key-papers/paper-vogelstein-surfing-p53-network-nature-2000/)

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