# PI3K delta (PIK3CD)

Source: https://onco.cc/targets/pik3cd/  
OnCo record `pik3cd` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The blood-cell version of the PI3K survival signal that keeps B cells alive. Idelalisib, duvelisib and copanlisib block it in chronic lymphocytic leukaemia and follicular lymphoma, at the price of immune-related colitis, liver inflammation and infections that have limited their use.

## Summary

The delta isoform of PI3K is restricted to white blood cells and relays B-cell receptor signalling, so blocking it starves malignant B cells of a survival signal. Idelalisib was approved in 2014 for relapsed CLL with rituximab and for follicular lymphoma, duvelisib in 2018 and copanlisib in 2017, but autoimmune-type toxicities, opportunistic infections and unfavourable survival signals in confirmatory trials led to the withdrawal of the follicular lymphoma indications in 2022 and of copanlisib in 2023. BTK inhibitors and venetoclax have largely taken their place, and the class is a case study in the limits of accelerated approval.

## Fields

- Kind: Target
- Last checked: 2026-09-04
- Symbol: PIK3CD
- Class: kinase
- Biology: Leukocyte-restricted class I PI3K catalytic subunit downstream of the B-cell receptor; isoform-selective inhibitors spare the ubiquitous alpha and beta isoforms.
- Where found: Chronic lymphocytic leukaemia; Follicular lymphoma

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/PIK3CD
- UniProt O00329: PIK3CD: https://www.uniprot.org/uniprotkb/O00329/entry

## Connected records

- cancers: [Chronic lymphocytic leukaemia](https://onco.cc/cancers/cll/), [Follicular lymphoma](https://onco.cc/cancers/follicular-lymphoma/)
- drugs: [Copanlisib](https://onco.cc/drugs/copanlisib/), [Duvelisib](https://onco.cc/drugs/duvelisib/), [Idelalisib](https://onco.cc/drugs/idelalisib/)
- companies: [MEI Pharma](https://onco.cc/companies/mei-pharma/), [SecuraBio](https://onco.cc/companies/securabio/), [TG Therapeutics](https://onco.cc/companies/tg-therapeutics/)

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JSON: https://onco.cc/api/v1/entities/pik3cd.json