Breast cancer:

Indications for PHESGO:

In combination with chemotherapy for the neoadjuvant treatment of patients with HER2-positive, locally advanced, inflammatory, or early stage breast cancer (either >2cm in diameter or node positive) as part of a complete treatment regimen for early breast cancer (EBC); or for adjuvant treatment of patients with HER2-positive EBC at high risk of recurrence. In combination with docetaxel for the treatment of patients with HER2-positive metastatic breast cancer (MBC) who have not received prior anti-HER2 therapy or chemotherapy for metastatic disease.

Adult Dosage:

Do not substitute for or with pertuzumab, trastuzumab, ado-trastuzumab emtansine, or fam-trastuzumab deruxtecan. Give as SC inj into thigh only; rotate inj sites between left and right thigh. Initially 1200mg/600mg/30000 Units over ~8mins, followed by 600mg/600mg/20000 Units over ~5mins every 3 weeks. Switching from IV pertuzumab/trastuzumab (if <6 weeks since last dose): give 600mg/600mg/20000 Units as a maintenance dose and every 3 weeks subsequently. Neoadjuvant: give every 3 weeks for 3–6 cycles as part of a treatment regimen. Following surgery, complete 1 year of treatment (up to 18 cycles) or until disease recurrence or unmanageable toxicity. Adjuvant: give every 3 weeks for a total of 1 year (up to 18 cycles) or until disease recurrence or unmanageable toxicity. Start on Day 1 of the first taxane-containing cycle (if standard anthracycline- and/or taxane-based chemotherapy is part of regimen). MBC: give initially with docetaxel 75mg/m2 IV infusion, may increase to 100mg/m2 every 3 weeks if initial dose is well tolerated. Continue until disease progression or unmanageable toxicity, whichever occurs first. Dose modification: see full labeling.

Children Dosage:

Not established.

Boxed Warning:

Cardiomyopathy. Embryo-fetal toxicity. Pulmonary toxicity.

PHESGO Warnings/Precautions:

Increased risk of cardiomyopathy. Conduct cardiac assessment (eg, history, physical exam, LVEF) prior to initiation. Assess LVEF at regular intervals during treatment (eg, every 12wks for MBC or EBC [once for neoadjuvant therapy]); permanently discontinue if LVEF has not improved, declined further, and/or symptomatic after repeat assessment within 3wks. Monitor and assess LVEF every 6 months for ≥2yrs after therapy (if adjuvant). Pretreatment LVEF value of <55% (EBC) or <50% (MBC), history of CHF, uncontrolled hypertension, recent MI, serious cardiac arrhythmia requiring treatment or a cumulative prior anthracycline exposure to >360mg/m2 of doxorubicin or its equivalent: not studied. Symptomatic intrinsic lung disease. Extensive tumor involvement of the lungs. Discontinue if anaphylaxis, angioedema, interstitial pneumonitis, or acute respiratory distress syndrome occurs. Monitor for hypersensitivity and injection-related reactions during and for 30mins after initial dose, and for 15mins after subsequent doses; slow or interrupt the injection and treat if occurs; permanently discontinue if anaphylaxis or severe reactions occur. Test for HER2 protein overexpression and HER2 gene amplification using FDA-approved tests specific for breast cancer. Elderly. Embryo-fetal toxicity (eg, oligohydramnios); monitor during pregnancy or within 7 months prior to conception. Advise females of reproductive potential to use effective contraception during and for 7 months after the last dose. Pregnancy: exclude status prior to initiation. Nursing mothers.

PHESGO Classification:

Human epidermal growth factor receptor (HER2) dimerization inhibitor + HER2 inhibitor + endoglycosidase.

PHESGO Interactions:

Increased cardiomyopathy with anthracycline-containing chemotherapy; if possible, avoid for up to 7 months after discontinuing Phesgo. Increased neutropenia with other myelosuppressive chemotherapy.

Adverse Reactions:

Alopecia, nausea, diarrhea, anemia, asthenia, neutropenia, fatigue, rash, myalgia, arthralgia, peripheral neuropathy, lab abnormalities; hypersensitivity reactions, inj site reactions, exacerbation of chemotherapy-induced neutropenia.

Generic Drug Availability:


How Supplied:

Single-dose vial—1

Pricing for PHESGO

10ml of 600mg/600mg/20000 units vial (Qty: 1)
Appx. price $8650