What is the clinical evidence from this study?

Study design: Observational. Population: Minor acute ischemic stroke (AIS) or high-risk transient ischemic attack (TIA) (n=35). Intervention: CYP2C19 loss-of-function (LOF) carrier status vs. CYP2C19 noncarriers. Primary outcome: Group difference in P2Y12 reaction units (PRUs) by CYP2C19 LOF carrier status (p=< 0.01).

What does this research mean for the field?

In patients receiving dual antiplatelet therapy after minor acute ischemic stroke or TIA, P2Y12 reaction units (PRUs) are significantly higher in CYP2C19 loss-of-function carriers, indicating potential utility as a surrogate marker for clopidogrel nonresponse despite lacking an association with short-term clinical outcomes. Novelty: ClaimNovelty.CONFIRMATORY. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

To evaluate whether P2Y12 reaction units can serve as a rapid surrogate biomarker for CYP2C19 loss-of-function genotypes and clopidogrel resistance in patients receiving dual antiplatelet therapy after minor stroke or transient ischemic attack.

September 14, 2026Pharmacotherapy The Journal of Human Pharmacology and Drug TherapyOpen Access

CYP2C19 LOF status is linked to ~65% higher P2Y12 reaction units versus noncarriers receiving DAPT.

Q: What are the key findings of this study?

CYP2C19 loss-of-function carrier status was associated with significantly higher mean P2Y12 reaction units compared with noncarriers (265 vs. 161; p < 0.01) in patients receiving DAPT after AIS or TIA.

Q: What does this research mean for the field?

In patients receiving dual antiplatelet therapy after minor acute ischemic stroke or TIA, P2Y12 reaction units (PRUs) are significantly higher in CYP2C19 loss-of-function carriers, indicating potential utility as a surrogate marker for clopidogrel nonresponse despite lacking an association with short-term clinical outcomes. Novelty: ClaimNovelty.CONFIRMATORY. Consensus alignment: ConsensusAlignment.NEUTRAL.

Q: What question did this study set out to answer?

To evaluate whether P2Y12 reaction units can serve as a rapid surrogate biomarker for CYP2C19 loss-of-function genotypes and clopidogrel resistance in patients receiving dual antiplatelet therapy after minor stroke or transient ischemic attack.

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Why the study?

Does CYP2C19 LOF carrier status associate with higher P2Y12 reaction units in adults receiving DAPT after minor AIS or TIA?

Population

35 adults with non-cardioembolic minor acute ischemic stroke or high-risk transient ischemic attack treated…

Comparison

CYP2C19 loss-of-function (LOF) carrier status vs CYP2C19 noncarriers

Design

Cohort

Follow-up

30-day

Key result

CYP2C19 loss-of-function carrier status was associated with significantly higher mean P2Y12 reaction units compared with noncarriers (265 vs. 161; p < 0.01) in patients receiving DAPT after AIS or TIA.

Authors

RSRachael M. Stone ASAnnie Smith SGSonya Gunter

Discussion

Member takes

Overview

May support genotype-guided DAPT after minor AIS/TIA; leaves open need for randomized confirmation in CYP2C19 LOF carriers.

Key Points

To evaluate whether P2Y12 reaction units can serve as a rapid surrogate biomarker for CYP2C19 loss-of-function genotypes and clopidogrel resistance in patients receiving dual antiplatelet therapy after minor stroke or transient ischemic attack.
Prospective observational study of 35 adults with non-cardioembolic minor acute ischemic stroke or high-risk transient ischemic attack treated with 21 days of dual antiplatelet therapy (aspirin and clopidogrel) between December 2021 and May 2023.
Measured P2Y12 reaction units (PRUs) via the VerifyNow P2Y12 assay at least 12 hours after a clopidogrel loading dose and assessed CYP2C19 loss-of-function (LOF) allele status alongside 30-day stroke recurrence.
Mean PRUs were significantly higher in CYP2C19 LOF carriers compared to noncarriers (265 vs. 161; p < 0.01).
High platelet reactivity (PRU ≥ 208) occurred in 83% of LOF carriers compared to 21% of noncarriers (p < 0.01).
Among 27 patients completing 30-day follow-up, 26% experienced recurrent stroke symptoms, but neither CYP2C19 LOF status nor high platelet reactivity was significantly associated with recurrence.

Study Design

Type

Observational (n=35)

Structured PICO

Does CYP2C19 LOF carrier status associate with higher P2Y12 reaction units in adults receiving DAPT after minor AIS or TIA?

Population

35 adults with non-cardioembolic minor acute ischemic stroke or high-risk TIA treated with 21 days of dual antiplatelet therapy, followed for 30 days.

Exposure

CYP2C19 loss-of-function (LOF) carrier status

Comparator

CYP2C19 noncarriers

Outcome

Group difference in P2Y12 reaction units (PRUs) by CYP2C19 LOF carrier status measured ≥ 12 h after a clopidogrel loading dosesurrogate

Main Result

Absolute Event Rate: 265% vs 161%

p-value: p=< 0.01

P2Y12 reaction units vary significantly by CYP2C19 genotype in patients receiving DAPT after minor AIS or TIA, suggesting utility as a surrogate marker for clopidogrel nonresponse when genotyping is unavailable.

Cite This Study

Stone et al. (2026) conducted an observational in Minor acute ischemic stroke (AIS) or high-risk transient ischemic attack (TIA) (n=35). CYP2C19 loss-of-function (LOF) carrier status vs. CYP2C19 noncarriers was evaluated on Group difference in P2Y12 reaction units (PRUs) by CYP2C19 LOF carrier status (p=< 0.01). CYP2C19 loss-of-function carrier status was associated with significantly higher mean P2Y12 reaction units compared with noncarriers (265 vs. 161; p < 0.01) in patients receiving DAPT after AIS or TIA.

synapsesocial.com/papers/6aa7afef79e9260bc85aacbf https://doi.org/10.1002/phar.70201

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September 14, 2026Pharmacotherapy The Journal of Human Pharmacology and Drug TherapyOpen Access

CYP2C19 LOF status is linked to ~65% higher P2Y12 reaction units versus noncarriers receiving DAPT.

View Full Paper

Ask AI

Bookmark

Why the study?

Does CYP2C19 LOF carrier status associate with higher P2Y12 reaction units in adults receiving DAPT after minor AIS or TIA?

Population

35 adults with non-cardioembolic minor acute ischemic stroke or high-risk transient ischemic attack treated…

Comparison

CYP2C19 loss-of-function (LOF) carrier status vs CYP2C19 noncarriers

Design

Cohort

Follow-up

30-day

Key result

Authors

RSRachael M. Stone ASAnnie Smith SGSonya Gunter

Discussion

Member takes

Overview

May support genotype-guided DAPT after minor AIS/TIA; leaves open need for randomized confirmation in CYP2C19 LOF carriers.

Key Points

To evaluate whether P2Y12 reaction units can serve as a rapid surrogate biomarker for CYP2C19 loss-of-function genotypes and clopidogrel resistance in patients receiving dual antiplatelet therapy after minor stroke or transient ischemic attack.
Prospective observational study of 35 adults with non-cardioembolic minor acute ischemic stroke or high-risk transient ischemic attack treated with 21 days of dual antiplatelet therapy (aspirin and clopidogrel) between December 2021 and May 2023.
Measured P2Y12 reaction units (PRUs) via the VerifyNow P2Y12 assay at least 12 hours after a clopidogrel loading dose and assessed CYP2C19 loss-of-function (LOF) allele status alongside 30-day stroke recurrence.
Mean PRUs were significantly higher in CYP2C19 LOF carriers compared to noncarriers (265 vs. 161; p < 0.01).
High platelet reactivity (PRU ≥ 208) occurred in 83% of LOF carriers compared to 21% of noncarriers (p < 0.01).
Among 27 patients completing 30-day follow-up, 26% experienced recurrent stroke symptoms, but neither CYP2C19 LOF status nor high platelet reactivity was significantly associated with recurrence.

Study Design

Type

Observational (n=35)

Structured PICO

Does CYP2C19 LOF carrier status associate with higher P2Y12 reaction units in adults receiving DAPT after minor AIS or TIA?

Population

35 adults with non-cardioembolic minor acute ischemic stroke or high-risk TIA treated with 21 days of dual antiplatelet therapy, followed for 30 days.

Exposure

CYP2C19 loss-of-function (LOF) carrier status

Comparator

CYP2C19 noncarriers

Outcome

Group difference in P2Y12 reaction units (PRUs) by CYP2C19 LOF carrier status measured ≥ 12 h after a clopidogrel loading dosesurrogate

Main Result

Absolute Event Rate: 265% vs 161%

p-value: p=< 0.01

Cite This Study

synapsesocial.com/papers/6aa7afef79e9260bc85aacbf https://doi.org/10.1002/phar.70201

Also Consider

Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context:

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