Elacestrant is an estrogen receptor antagonist indicated for the treatment of postmenopausal women or adult men with ER-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer with disease progression following at least one line of endocrine therapy.

Elacestrant is an estrogen receptor antagonist that binds to estrogen receptor-alpha (ERα). In ER-positive (ER+) HER2-negative (HER2-) breast cancer cells, elacestrant inhibited 17β-estradiol mediated cell proliferation at concentrations inducing degradation of ERα protein mediated through the proteasomal pathway. Elacestrant demonstrated in vitro and in vivo antitumor activity including in ER+ HER2- breast cancer models resistant to fulvestrant and cyclin-dependent kinase 4/6 inhibitors and those harboring estrogen receptor 1 gene (ESR1) mutations.

Patient Selection: Select patients for treatment of ER-positive, HER2-negative advanced or metastatic breast cancer with Elacestrant based on the presence of ESR1 mutation(s) in plasma specimen using an FDA-approved test.

Recommended Dosage: The recommended dosage of Elacestrant is 345 mg taken orally with food once daily until disease progression or unacceptable toxicity occurs. Take Elacestrant at approximately the same time each day. Take with food to reduce nausea and vomiting. Swallow Elacestrant tablet(s) whole. Do not chew, crush, or split prior to swallowing. Do not take any Elacestrant tablets that are broken, cracked, or that look damaged. If a dose is missed for more than 6 hours or vomiting occurs, skip the dose and take the next dose the following day at its regularly scheduled time.

Strong and Moderate CYP3A4 Inhibitors: Avoid concomitant use of strong or moderate CYP3A inhibitors with Elacestrant. Elacestrant is a CYP3A4 substrate. Concomitant use of a strong or moderate CYP3A4 inhibitor increases elacestrant exposure, which may increase the risk of adverse reactions of Elacestrant.

Strong and Moderate CYP3A4 Inducers: Avoid concomitant use of strong or moderate CYP3A inducers with Elacestrant. Elacestrant is a CYP3A4 substrate. Concomitant use of a strong or moderate CYP3A4 inducer decreases elacestrant exposure, which may decrease the effectiveness of Elacestrant.

The most common (>10%) adverse reactions, including laboratory abnormalities, of Elacestrant were musculoskeletal pain, nausea, increased cholesterol, increased AST, increased triglycerides, fatigue, decreased hemoglobin, vomiting, increased ALT, decreased sodium, increased creatinine, decreased appetite, diarrhea, headache, constipation, abdominal pain, hot flush, and dyspepsia.

Based on findings in animals and its mechanism of action, Elacestrant can cause fetal harm when administered to a pregnant woman. There are no available human data on Elacestrant use in pregnant women to inform the drug-associated risk. There are no data on the presence of elacestrant in human milk, its effects on milk production, or the breastfed child. Because of the potential for serious adverse reactions in the breastfed child, advise lactating women to not breastfeed during treatment with Elacestrant and for 1 week after the last dose.

Dyslipidemia: Hypercholesterolemia and hypertriglyceridemia occurred in patients taking Elacestrant at an incidence of 30% and 27%, respectively. The incidence of Grade 3 and 4 hypercholesterolemia and hypertriglyceridemia were 0.9% and 2.2%, respectively.

Embryo-Fetal Toxicity: Based on findings in animals and its mechanism of action, Elacestrant can cause fetal harm when administered to a pregnant woman. Administration of elacestrant to pregnant rats resulted in adverse developmental outcomes, including embryo-fetal mortality and structural abnormalities, at maternal exposures below the recommended dose based on area under the curve (AUC). Advise pregnant women and females of reproductive potential of the potential risk to a fetus. Advise females of reproductive potential to use effective contraception during treatment with Elacestrant and for 1 week after the last dose. Advise male patients with female partners of reproductive potential to use effective contraception during treatment with Elacestrant and for 1 week after the last dose.

Cytotoxic Chemotherapy

Keep below 30°C temperature, away from light & moisture. Keep out of the reach of children.