# Caution: chemoimmunotherapy in del(17p)/TP53 CLL

Source: https://onco.cc/pairings/cit-in-del17p-caution/  
OnCo record `cit-in-del17p-caution` (Pairing). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Chemotherapy-based regimens barely work when the p53 gene is lost; these patients need BTK inhibitors or venetoclax from the start.

## Summary

This caution concerns rituximab-based chemoimmunotherapy in chronic lymphocytic leukaemia with del(17p) or TP53 mutation. Alkylators and purine analogues kill through p53-dependent apoptosis, so loss of TP53 removes the mechanism: FCR and BR give only short remissions in these patients and may select resistant clones. The pattern is consistent across the CLL8 and CLL10 trials and registry data, and guidelines from NCCN, ESMO and iwCLL restrict chemoimmunotherapy to fit patients with intact TP53 and mutated IGHV, with targeted therapy preferred even there. Patients with del(17p) or TP53 aberration should start on a BTK inhibitor such as zanubrutinib, tested in SEQUOIA, or on venetoclax.

## Fields

- Kind: Pairing
- Last checked: 2026-09-07
- Pairs: Rituximab + del(17p) / TP53 aberration in CLL
- Type: caution
- Rationale: Alkylators and purine analogues kill via p53-dependent apoptosis; TP53 loss removes the mechanism.
- Evidence: Consistent across CLL8, CLL10, and registry data.

## Sources

- ClinicalTrials.gov NCT03336333: SEQUOIA: https://clinicaltrials.gov/study/NCT03336333

## Connected records

- cancers: [Chronic lymphocytic leukaemia](https://onco.cc/cancers/cll/), [Chronic lymphocytic leukaemia, first treatment](https://onco.cc/cancers/cll-treatment-naive/)
- drugs: [Rituximab](https://onco.cc/drugs/rituximab/), [Venetoclax](https://onco.cc/drugs/venetoclax/), [Zanubrutinib](https://onco.cc/drugs/zanubrutinib/)
- terms: [del(17p) / TP53 aberration in CLL](https://onco.cc/terms/del17p-tp53/)
- trials: [SEQUOIA](https://onco.cc/trials/sequoia/)

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