Patient Selection

Select patients for treatment of ER-positive, HER2-negative advanced or metastatic breast cancer with ORSERDU based on the presence of ESR1 mutation(s) in plasma specimen using an FDA-approved test [see Indications and Usage (1) and Clinical Studies (14)].

Information on FDA-approved tests for detection of ESR1 mutations in breast cancer is available at: http://www.fda.gov/CompanionDiagnostics.

Recommended Dosage

The recommended dosage of ORSERDU is 345 mg taken orally with food once daily until disease progression or unacceptable toxicity occurs.

Take ORSERDU at approximately the same time each day. Take with food to reduce nausea and vomiting [see Adverse Reactions (6.1)].

Swallow ORSERDU tablet(s) whole. Do not chew, crush, or split prior to swallowing. Do not take any ORSERDU 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.

Dosage Modifications for Adverse Reactions

The recommended dose reduction levels for adverse reactions are listed in Table 1:

Table 1: ORSERDU Dose Reduction Levels for Adverse Reactions

Recommended dosage modifications of ORSERDU for adverse reactions are provided in Table 2 [see Adverse Reactions (6.1)].

Table 2: ORSERDU Dosage Modification Guidelines for Adverse Reactions

Dosage Modifications for Use with Concomitant CYP3A4 Inducers and Inhibitors

Avoid concomitant use of ORSERDU with strong or moderate CYP3A4 inducers and inhibitors [see Drug Interactions (7.1)].

Dosage Modifications for Hepatic Impairment

Avoid use of ORSERDU in patients with severe hepatic impairment (Child-Pugh C). Reduce the ORSERDU dosage to 258 mg once daily for patients with moderate hepatic impairment (Child-Pugh B). No dosage adjustment is recommended for patients with mild hepatic impairment (Child-Pugh A) [see Clinical Pharmacology (12.3)].