Elacestrant

Strong and Moderate CYP3A4 Inducers : Avoid concomitant use. ( 7.1 ) Strong and Moderate CYP3A4 Inhibitors : Avoid concomitant use. ( 7.1 )

7.1 Effect of Other Drugs on ORSERDU Strong and Moderate CYP3A4 Inhibitors Avoid concomitant use of strong or moderate CYP3A inhibitors with ORSERDU. Elacestrant is a CYP3A4 substrate. Concomitant use of a strong or moderate CYP3A4 inhibitor increase elacestrant exposure [see Clinical Pharmacology ( 12.3 )] , which may increase the risk of adverse reactions of ORSERDU. Strong and Moderate CYP3A4 Inducers Avoid concomitant use of strong or moderate CYP3A inducers with ORSERDU. Elacestrant is a CYP3A4 substrate. Concomitant use of a strong or moderate CYP3A4 inducer decreases elacestrant exposure [see Clinical Pharmacology ( 12.3 )] , which may decrease effectiveness of ORSERDU.

7.2 Effect of ORSERDU on Other Drugs P-gp Substrates Reduce the dosage of P-gp substrates per their Prescribing Information when minimal concentration changes may lead to serious or life-threatening adverse reactions. Elacestrant is a P-gp inhibitor. Concomitant use of ORSERDU with a P-gp substrate increased the concentrations of P-gp substrate [see Clinical Pharmacology ( 12.3 )] , which may increase the adverse reactions associated with a P-gp substrate. BCRP Substrates Reduce the dosage of BCRP substrates per their Prescribing Information when minimal concentration changes may lead to serious or life-threatening adverse reactions. Elacestrant is a BCRP inhibitor.

Concomitant use of ORSERDU with a BCRP substrate increased the plasma concentrations of BCRP substrate [see Clinical Pharmacology ( 12.3 )] , which may increase the adverse reactions associated with a BCRP substrate.

8.1 Pregnancy Risk Summary Based on findings in animals and its mechanism of action, ORSERDU can cause fetal harm when administered to a pregnant woman [see Clinical Pharmacology ( 12.1 )] . There are no available human data on ORSERDU use in pregnant women to inform the drug-associated risk. In an animal reproduction study, oral administration of elacestrant to pregnant rats during organogenesis caused embryo-fetal mortality and structural abnormalities at maternal exposures below the recommended dose based on AUC (see Data ) . Advise pregnant women and females of reproductive potential of the potential risk to a fetus.

The background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2%-4% and 15%-20%, respectively.

Data Animal Data In an embryo-fetal development study in pregnant rats, administration of oral doses of elacestrant up to 30 mg/kg/day during the period of organogenesis resulted in maternal toxicity (reduced body weight gain, low food consumption, red vulvar discharge) and embryo-fetal mortality (increased resorptions, post-implantation loss, and reduced number of live fetuses) at ≥ 3 mg/kg/day (approximately 0.1 times the human AUC at the recommended dose).

Additional adverse effects included reduced fetal weight and external malformations of the limbs (hyperflexion, malrotation) and head (domed, misshapen, flattened) with corresponding skeletal malformations of the skull at doses ≥ 10 mg/kg/day (approximately 0.5 times the human AUC at the recommended dose).