FDA Approves Herceptin Hylecta (trastuzumab/hyaluronidase) for HER2+ Breast Cancer

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FDA Published May 22, 2026 Medically reviewed May 22, 2026 DOI ↗ By Dr. Julia Lee, PhD · Oncology, Genomics & Drug Development

Key Takeaway

Consider Herceptin Hylecta as a subcutaneous alternative to IV trastuzumab for HER2+ breast cancer, with fixed dosing every 3 weeks.

The FDA has approved Herceptin Hylecta (trastuzumab and hyaluronidase) for the treatment of HER2-overexpressing breast cancer in adults. This subcutaneous formulation offers a fixed dose of 600 mg trastuzumab and 10,000 units hyaluronidase administered over 2-5 minutes once every three weeks, eliminating the need for intravenous infusion and loading doses. The approval covers both adjuvant therapy for node-positive or high-risk node-negative breast cancer and first-line or later-line treatment for metastatic disease. Clinicians should note that Herceptin Hylecta is not interchangeable with intravenous trastuzumab or ado-trastuzumab emtansine. Patient selection requires FDA-approved companion diagnostic testing for HER2 overexpression or amplification.

＋ Clinical Details (Mechanism · Dosing · Trial Data · Warnings)

Mechanism of Action

Trastuzumab is a HER2/neu receptor antagonist. Hyaluronidase is an endoglycosidase that temporarily degrades hyaluronan in the subcutaneous space, increasing permeability and allowing trastuzumab absorption.

Indication & Patient Population

Herceptin Hylecta is indicated for adults with HER2-overexpressing breast cancer. For adjuvant treatment: node-positive or node-negative (ER/PR negative or with one high-risk feature) breast cancer, as part of a regimen with doxorubicin, cyclophosphamide, and paclitaxel or docetaxel; with docetaxel and carboplatin; or as a single agent after anthracycline-based therapy. For metastatic breast cancer: in combination with paclitaxel for first-line treatment, or as a single agent after one or more prior chemotherapy regimens. Selection based on FDA-approved companion diagnostic.

Dosing & Administration

Subcutaneous use only. Dose: 600 mg trastuzumab/10,000 units hyaluronidase once every 3 weeks over 2-5 minutes. No loading dose. No dose adjustments for body weight or concomitant chemotherapy. Adjuvant: treat for 52 weeks or until recurrence. Metastatic: treat until progression. Missed dose: administer as soon as possible, with at least 3 weeks between doses. For cardiomyopathy: withhold for ≥16% absolute LVEF decrease or LVEF below normal with ≥10% decrease; resume if LVEF returns to normal within 4-8 weeks; permanently discontinue for persistent >8 weeks decline or >3 suspensions.

Key Clinical Trial Data

Trial data not available in label.

Warnings & Contraindications

Cardiomyopathy: assess LVEF before and during treatment. Withhold or discontinue per dosing modification guidelines. Verify pregnancy status before initiation. Do not administer intravenously. Do not substitute for or with ado-trastuzumab emtansine.

Place in Therapy

Herceptin Hylecta provides a subcutaneous alternative to intravenous trastuzumab for HER2-positive breast cancer, offering convenience of fixed dosing and shorter administration time. It is indicated for both adjuvant and metastatic settings, with specific combination or monotherapy regimens as described.

Study Details

Study typeFda approval

PublishedFeb 2019

View Original Abstract ↓

1 INDICATIONS AND USAGE HERCEPTIN HYLECTA is a combination of trastuzumab, a HER2/neu receptor antagonist, and hyaluronidase, an endoglycosidase, indicated in adults for: The treatment of HER2-overexpressing breast cancer. ( 1.1 , 1.2 ) Select patients for therapy based on an FDA-approved companion diagnostic for trastuzumab. ( 1 , 2.2 ) 1.1 Adjuvant Breast Cancer HERCEPTIN HYLECTA is indicated for adjuvant treatment of adults with HER2 overexpressing node positive or node negative (ER/PR negative or with one high risk feature [see Clinical Studies (14.1) ] ) breast cancer: as part of a treatment regimen consisting of doxorubicin, cyclophosphamide, and either paclitaxel or docetaxel as part of a treatment regimen with docetaxel and carboplatin as a single agent following multi-modality anthracycline based therapy. Select patients for therapy based on an FDA-approved companion diagnostic for trastuzumab [see Dosage and Administration (2.2) ] . 1.2 Metastatic Breast Cancer HERCEPTIN HYLECTA is indicated in adults: In combination with paclitaxel for first-line treatment of HER2-overexpressing metastatic breast cancer As a single agent for treatment of HER2-overexpressing breast cancer in patients who have received one or more chemotherapy regimens for metastatic disease. Select patients for therapy based on an FDA-approved companion diagnostic for trastuzumab [see Dosage and Administration (2.2) ] .