Breast cancer:

Indications for: ORSERDU

In postmenopausal women or adult men, with ER-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer with disease progression following at least 1 line of endocrine therapy.

Adult Dosage:

Select patients based on the presence of ESR1 mutation(s) in plasma specimen. Swallow whole. Take with food. 345mg once daily, until disease progression or unacceptable toxicity occurs. Moderate hepatic impairment (Child-Pugh B): 258mg once daily. Dose modifications for adverse reactions: see full labeling.

Children Dosage:

Not established.

ORSERDU Warnings/Precautions:

Risk for dyslipidemia. Monitor lipid profile prior to initiation and periodically during treatment. Hepatic impairment (severe): avoid; (moderate): reduce dose. Embryo-fetal toxicity. Advise females of reproductive potential and males (w. female partners) to use effective contraception during and for 1 week after the last dose. Pregnancy: exclude status prior to initiation. Nursing mothers: not recommended (during and for 1 week after the last dose).

ORSERDU Classification:

Estrogen receptor antagonist.

ORSERDU Interactions:

Potentiated by moderate or strong CYP3A4 inhibitors (eg, fluconazole, itraconazole); avoid. Antagonized by moderate or strong CYP3A4 inducers (eg, efavirenz, rifampin); avoid. Potentiates P-gp or BCRP substrates (eg, digoxin, rosuvastatin); reduce dose of substrates when concomitant Orserdu.

Adverse Reactions:

Musculoskeletal pain, nausea, fatigue, vomiting, decreased appetite, diarrhea, headache, constipation, abdominal pain, hot flush, dyspepsia, lab abnormalities (increased cholesterol, increased AST/ALT, increased triglycerides, decreased hemoglobin,  decreased sodium, increased creatinine).


Primarily metabolized by CYP3A4 and to a lesser extent by CYP2A6 and CYP2C9.

Drug Elimination:

Fecal (82%), renal (7.5%). Half-life: 30 to 50 hours.

Generic Drug Availability:


How Supplied: