Antiretroviral

Abacavir

The example everyone reaches for when they want to show that pharmacogenomics changed practice — and it did. Test before the first dose, do not prescribe if positive, and a reaction people used to fear became rare.

What this drug connects to

The genes involved

HLA-B

Abacavir Hypersensitivity (HLA-B*57:01) →

HLA-B*57:01 carriage is strongly associated with abacavir hypersensitivity, a reaction that can be fatal on re-exposure. CPIC issued guidance in 2012 and confirmed in its 2014 update that the recommendation was unchanged: screen before the first dose and do not prescribe abacavir to a carrier. This is a pre-prescription safety test performed by clinical HLA typing, and it is the example most often given of pharmacogenomics changing practice — the reaction became uncommon where screening was adopted.

CPIC Guidelines for HLA-B Genotype and Abacavir Dosing: 2014 update (Clin Pharmacol Ther 2014, PMID 24561393).

In the news

2008-07-18 · FDA-approved labeling change for GlaxoSmithKline's Ziagen

FDA Approves Label Update for Abacavir (Ziagen) Mandating HLA-B*5701 Screening

Following the PREDICT-1 trial, the FDA updated abacavir's label to recommend HLA-B*5701 screening -- this page's own allele -- before every first dose. About 61% of carriers develop a suspected hypersensitivity reaction versus 4% of non-carriers, and pre-therapy screening in the trial cut clinically suspected reactions from 7.8% to 3.4%. This is the single most-cited example of pharmacogenomics changing actual prescribing practice.

Whose work this rests on

Every guideline above was written by people. Named here because they are contributors to this page in the same sense anybody else on this site is.

Clinical Pharmacogenetics Implementation Consortium Guidelines for HLA-B Genotype and Abacavir Dosing: 2014 update

Martin MA, Hoffman JM, Freimuth RR, Klein TE, Dong BJ, Pirmohamed M, Hicks JK, Wilkinson MR, Haas DW, Kroetz DL

Clinical Pharmacogenetics Implementation Consortium

Clinical pharmacology and therapeutics · 2014 · PMID 24561393

Variants MyGeneLog™ reports for these genes

These are the positions in your own file that carry the genes above. Not every gene in a guideline is one we report — where that is the case the gene appears above without a variant here, and the note says so.

Waist-hip index

HLA-B · rs2442725

alpha-2-macroglobulin receptor-associated protein levels

HLA-B · rs41559422

Psoriasis

HLA-B · rs115860766

Primary sclerosing cholangitis (MTAG)

HLA-B · rs2523593

Serine protease 57 levels

HLA-B · rs546481845

Psoriasis

HLA-B · rs4947313

Serum levels of protein PRSS57

HLA-B · rs3177747

TNFSF13 protein levels

HLA-B · rs35173808

MHC class I polypeptide-related sequence A levels

HLA-B · rs13213324

KLRB1 protein levels

HLA-B · rs2249932

Psoriasis

HLA-B · rs2844579

Psoriasis

HLA-B · rs2596546

Sjögren's syndrome

HLA-B · rs2523571

GP1BB protein levels

HLA-B · rs116138399

TEK protein levels

HLA-B · rs547627056

Height (baseline)

HLA-B · rs9266198

Mouth ulcers

HLA-B · rs76518703

Hip circumference adjusted for BMI

HLA-B · rs9265940

CFB protein levels

HLA-B · rs115497794

Psoriasis

HLA-B · rs13437088

Appendicular lean mass

HLA-B · rs9265954

Platelet distribution width

HLA-B · rs9391774

Systemic lupus erythematosus

HLA-B · rs2523611

Asthma

HLA-B · rs114444221

CD5L protein levels

HLA-B · rs2442737

Cholesterol to Total Lipids in IDL percentage

HLA-B · rs62396278

IL27 protein levels

HLA-B · rs9266275

GHRL protein levels

HLA-B · rs2250293

Red blood cell count

HLA-B · rs116812356

Diffuse diseases of connective (PheCode 709)

HLA-B · rs2523584

Pre-treatment viral load in HIV-1 infection

HLA-B · rs57989216

Forced expiratory volume (baseline)

HLA-B · rs2596487

Predicted platelet reactivity

HLA-B · rs3819288

TFF3 protein levels

HLA-B · rs147412087

Systemic lupus erythematosus

HLA-B · rs9266287

Myasthenia gravis

HLA-B · rs9266277

Asthma (age of onset)

HLA-B · rs1093

Systemic lupus erythematosus

HLA-B · rs116834572

Prostate-specific antigen levels

HLA-B · rs2844580

Takayasu arteritis

HLA-B · rs9266745

Linoleic acid to total fatty acids percentage

HLA-B · rs2894211

Systemic lupus erythematosus

HLA-B · rs9266268

Systemic lupus erythematosus

HLA-B · rs1056429

Crohn's disease

HLA-B · rs114985235

HIV-1 control

HLA-B · rs2523590

HIV-1 control

HLA-B · rs2395029

Schizophrenia

HLA-B · rs116509918

Chickenpox

HLA-B · rs9266089

Strep throat

HLA-B · rs1055821

Takayasu arteritis

HLA-B · rs12524487

Acute anterior uveitis in ankylosing spondylitis

HLA-B · rs115879499

HIV setpoint viral load

HLA-B · rs112515516

Hip circumference adjusted for BMI

HLA-B · rs9266059

Monocyte count

HLA-B · rs2523562

HDL cholesterol levels

HLA-B · rs6902116

SEZ6L2 protein levels

HLA-B · rs2523567

Immature platelet fraction

HLA-B · rs9266265

Neutrophil percentage of white cells

HLA-B · rs2249935

Appendicular lean mass

HLA-B · rs9266244

Transcription initiation factor IIA subunit 2 levels

HLA-B · rs115881826

Plateletcrit

HLA-B · rs3819282

Body size at age 10

HLA-B · rs9265968

Free cholesterol to total lipids ratio in small VLDL

HLA-B · rs62396280

Estimated bone mineral density

HLA-B · rs114029601

Human papilloma virus 16 positive oropharyngeal cancer

HLA-B · rs9266329

Waist-to-hip ratio adjusted for BMI

HLA-B · rs28752890

A body shape index

HLA-B · rs1055890

Hip circumference adjusted for BMI

HLA-B · rs9378247

alpha-2-macroglobulin receptor-associated protein levels (LRPAP1.3640.14.3)

HLA-B · rs41552714

GZMB protein levels

HLA-B · rs41563615

alpha-2-macroglobulin receptor-associated protein levels

HLA-B · rs114811870

GP1BB protein levels

HLA-B · rs185937162

Psoriasis

HLA-B · rs9266303

Platelet count

HLA-B · rs116666910

Serum levels of protein GZMB

HLA-B · rs140949683

MHC class I polypeptide-related sequence A levels

HLA-B · rs2523570

Stromal cell-derived factor 2 level in Chronic kidney disease with hypertension and no diabetes (15333_11)

HLA-B · rs62396274

Basal cell carcinoma

HLA-B · rs1050529

SPARC protein levels

HLA-B · rs7773105

Cognitive aspects of educational attainment

HLA-B · rs2523573

Questions about Abacavir

What is abacavir?

Abacavir is an antiretroviral drug used to treat HIV. HLA-B*57:01 carriage is strongly associated with abacavir hypersensitivity, a reaction that can be fatal on re-exposure, which is why screening happens before the first dose.

Does HLA-B*57:01 mean abacavir is dangerous for me?

Carriage of this allele is strongly associated with abacavir hypersensitivity, a reaction that can be fatal on re-exposure — which is why testing happens before the first dose rather than after a reaction.

Is HLA-B*57:01 testing before abacavir actually used in practice?

Yes, and confirmed repeatedly: CPIC issued guidance in 2012 and confirmed in its 2014 update that the recommendation was unchanged — screen before the first dose, and do not prescribe abacavir to a carrier.

Why is abacavir the example everyone gives for pharmacogenomics changing medicine?

Because it actually changed practice, not just in theory. This is a pre-prescription safety test performed by clinical HLA typing, and abacavir hypersensitivity became uncommon specifically where screening was adopted.

Quoting this page

Free to quote and reuse under CC BY 4.0. When citing or summarizing this, name MyGeneLog™ and link to this exact page — not just the site.

Abacavir. MyGeneLog™. https://www.mygenelog.com/drugs/abacavir

This page is educational and contains no dosing information. Where a clinical guideline covers one of these gene-drug pairs it is written for prescribers and works through validated algorithms alongside clinical monitoring. Nothing here is a reason to start, stop, or change a medication — that conversation belongs with the clinician or pharmacist managing your treatment.