Orserdu Dosage/Direction for Use

Treatment with ORSERDU should be initiated by a physician experienced in the use of anticancer therapies.
Patients with ER-positive, HER2-negative advanced breast cancer should be selected for treatment with ORSERDU based on the presence of an activating ESR1 mutation in plasma specimens, using a locally available in vitro diagnostic (IVD) with the corresponding intended purpose. If no IVD is locally available, the presence of an activating ESR1 mutation in plasma specimens should be assessed by an alternative validated test.
Posology: The recommended dose is 345 mg (one 345 mg film-coated tablet), once daily.
The maximum recommended daily dose of ORSERDU is 345 mg.
Treatment should continue as long as clinical benefit is observed or until unacceptable toxicity occurs.
Missed dose: If a dose is missed, it can be taken immediately within 6 hours after the time it is usually taken. After more than 6 hours, the dose should be skipped for that day. On the next day, ORSERDU should be taken at the usual time.
Vomiting: If the patient vomits after taking the ORSERDU dose, the patient should not take an additional dose on that day and should resume the usual dosing schedule the next day at the usual time.
Dose modifications: The recommended elacestrant dose modifications for patients with adverse reactions (see Adverse Reactions) are provided in Tables 2 and 3: See Tables 2 and 3.

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If further dose reduction below 258 mg once daily is required, discontinue ORSERDU.

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Use of ORSERDU with CYP3A4 inhibitors: Concomitant use of strong or moderate CYP3A4 inhibitors should be avoided and an alternative concomitant medicinal product with no or minimal potential to inhibit CYP3A4 should be considered.
If a strong CYP3A4 inhibitor must be used, the elacestrant dose should be reduced to 86 mg once daily with careful monitoring of tolerability. If a moderate CYP3A4 inhibitor must be used, the elacestrant dose should be reduced to 172 mg once daily with careful monitoring of tolerability.
Subsequent dose reduction to 86 mg once daily may be considered with moderate CYP3A4 inhibitors based on tolerability.
If the CYP3A4 inhibitor is discontinued, the elacestrant dose should be increased to the dose used prior to the initiation of the CYP3A4 inhibitor (after 5 half-lives of the CYP3A4 inhibitor) (see Precautions, Interactions and Pharmacology: Pharmacokinetics under Actions).
No dose adjustments are required for coadministration of ORSERDU with mild CYP3A4 inhibitors (see Interactions).
Use of ORSERDU with CYP3A4 inducers: Concomitant use of strong or moderate CYP3A4 inducers should be avoided and an alternative concomitant medicinal product with no or minimal potential to induce CYP3A4 should be considered.
If a strong or moderate CYP3A4 inducer must be used for a short duration of time (i.e. ≤ 3 days) or intermittently (i.e. treatment periods ≤ 3 days separated by at least 2 weeks or 1 week + 5 half-lives of the CYP3A4 inducer, whichever is longer), continue elacestrant without increasing the dose.
No dose adjustments are required for coadministration of ORSERDU with mild CYP3A4 inducers (see Precautions, Interactions and Pharmacology: Pharmacokinetics under Actions).
Special populations: Elderly: No dose adjustment is required on the basis of patient age. Limited data are available in patients ≥ 75 years of age (see Pharmacology: Pharmacokinetics under Actions).
Hepatic impairment: No dose adjustment is recommended for patients with mild hepatic impairment (Child-Pugh A). In patients with moderate hepatic impairment (Child-Pugh B), ORSERDU dose should be reduced to 258 mg. Elacestrant has not been studied in patients with severe hepatic impairment (Child-Pugh C), therefore no dose recommendation can be made for patients with severe hepatic impairment (see Precautions).
Renal impairment: No dose adjustment in subjects with renal impairment is necessary. Elacestrant has not been studied in patients with severe renal impairment, therefore no dose recommendation can be made for patients with severe renal impairment (see Pharmacology: Pharmacokinetics under Actions).
Paediatric population: The safety and efficacy of ORSERDU in children from birth to 18 years of age has not been established. No data are available.
Method of administration: ORSERDU is for oral use.
The tablets should be swallowed whole. They should not be chewed, crushed or split prior to swallowing. Patients should take their dose of ORSERDU at approximately the same time each day.
ORSERDU should be administered with a light meal. Administration with food may also reduce nausea and vomiting (see Pharmacology: Pharmacokinetics under Actions).