# Rechallenge and retreatment

Source: https://onco.cc/terms/rechallenge/  
OnCo record `rechallenge` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Giving a drug again after a break, on the theory that the cancer's resistance faded while it was off the drug. Sometimes it works: bowel cancers can respond again to EGFR antibodies once resistant clones have receded.

## Summary

Anti-EGFR rechallenge in RAS wild-type colorectal cancer works when ctDNA shows RAS-mutant clones have declined (CHRONOS, CRICKET). Platinum rechallenge is standard for platinum-sensitive relapse in ovarian and small-cell lung cancer; BTK inhibitor or venetoclax retreatment after fixed-duration CLL therapy is effective; checkpoint inhibitor rechallenge after stopping for toxicity or after a treatment-free interval gives responses in a minority. Planned drug holidays (intermittent ADT, stop-and-go FOLFOX in OPTIMOX, adaptive therapy in prostate cancer) trade some disease control for toxicity relief and may slow resistance by preserving sensitive cells.

## Fields

- Kind: Term
- Last checked: 2026-09-09
- Also known as: re-challenge; rechallenged; retreatment; re-treatment; re-treated; platinum rechallenge; anti-EGFR rechallenge; immunotherapy rechallenge; re-exposure; re-induction; drug holiday; treatment holiday; treatment break; intermittent therapy; intermittent dosing; stop-and-restart; stop and go; drug holidays

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Drug_holiday
- Wikipedia: https://en.wikipedia.org/wiki/Drug_holiday

## Connected records

- terms: [Cross-resistance](https://onco.cc/terms/cross-resistance/), [Fixed-duration vs continuous therapy](https://onco.cc/terms/fixed-duration/), [Platinum-sensitive / platinum-resistant](https://onco.cc/terms/platinum-sensitivity/)
- pathways: [Clonal evolution & minimal residual disease](https://onco.cc/pathways/clonal-evolution/)
- fronts: [Chemotherapy](https://onco.cc/fronts/chemotherapy/)

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JSON: https://onco.cc/api/v1/entities/rechallenge.json