PDGFRA exon 18 mutation (D842V)

aka PDGFRA D842V, D842V, PDGFRA exon 18, PDGFRA exon 18 mutation, PDGFRA-mutant GIST

PDGFRA D842V drives about 5 percent of gastrointestinal stromal tumours and is resistant to imatinib. Avapritinib is the approved drug for GISTs with PDGFRA exon 18 mutations including D842V.

Exon 18 mutations sit in the activation loop; D842V, the commonest, stabilises the active kinase and blocks imatinib, sunitinib and regorafenib binding. Avapritinib (Ayvakit, 2020) is labelled for unresectable or metastatic GIST harbouring a PDGFRA exon 18 mutation, including D842V, and the therascreen PDGFRA RGQ PCR Kit is its companion diagnostic (P210002, 2023). Non-D842V exon 18 mutations remain partly imatinib-sensitive, so the exact variant is reported.

Part ofPDGFRA· PDGFRA All readouts

PDGFRA: what it is and how drugs act on it · animated schematic, not to scale

Target · the protein and the cell it sits on
Drug · antibody, small molecule, cell or radioligand
Effect · signal, damage or kill

In plain words · PDGFRA is a growth-factor receptor mutated in about 10% of GISTs, including the D842V mutation that resists imatinib but responds to avapritinib.

Sequencing 1 approval threshold

What it means for a patient

If your GIST carries a PDGFRA D842V mutation, imatinib is unlikely to work and avapritinib tablets are the on-label treatment for advanced disease. Every GIST should have KIT and PDGFRA sequenced before treatment, because the mutation decides the drug and the dose.

Written only from the label or guideline text cited on this page. Not medical advice; your own report and the reading your team gives it come first.

Scoring rule

A PDGFRA exon 18 mutation, including D842V, by the therascreen PDGFRA RGQ PCR Kit or sequencing of tumour tissue.

“PDGFRA: D842V”
FDA: List of FDA-Authorized Companion Diagnostic Devices

Thresholds used in approvals

Threshold	Drug	Cancer	Regulator	Source
PDGFRA exon 18 mutation including D842V	Avapritinib	PDGFRA D842V-mutant GIST	FDA	label

Drugs whose label names it

Avapritinib

Companion diagnostics (FDA list)

Device	Maker	Indication and sample	Drug	PMA / 510(k)
therascreen PDGFRA RGQ PCR Kit	QIAGEN	Gastrointestinal Stromal Tumors (GIST) - Tissue	Avapritinib	P210002 (06/29/2023)

Tests that measure it

Tempus xT and xT CDx FoundationOne CDx Caris MI Profile

Trials that name this readout

Matched on the name and aliases of the readout in the title, setting and summary of each trial; a match is a mention, not proof the readout was an entry criterion.