Last reviewed 2026-04-20 · How we verify

Trastuzumab and Hyaluronidase-oysk

Trastuzumab and Hyaluronidase-oysk is a Endoglycosidase [EPC] Small molecule drug developed by Adrienne G. Waks. It is currently FDA-approved for Adjuvant Treatment of HER2-Overexpressing Breast Cancer, First-Line Treatment of HER2-Overexpressing Metastatic Breast Cancer, Treatment of HER2-Overexpressing Metastatic Breast Cancer After Chemotherapy. Also known as: Herceptin Hylecta.

Trastuzumab inhibits HER2-overexpressing tumor cell proliferation and mediates ADCC, while hyaluronidase increases subcutaneous permeability for better drug absorption.

Trastuzumab and Hyaluronidase-oysk, marketed by Adrienne G. Waks, is an adjuvant treatment for HER2-overexpressing breast cancer, leveraging a unique combination of trastuzumab's HER2 inhibition and hyaluronidase's enhanced subcutaneous delivery. The key strength lies in its mechanism of action, which not only inhibits tumor cell proliferation but also improves drug absorption through increased subcutaneous permeability. The primary risk is the key composition patent expiry in 2028, which could lead to increased competition from generics and biosimilars.

At a glance

Mechanism of action

Trastuzumab targets HER2-overexpressing cancer cells, stopping their growth and promoting their destruction through ADCC. Hyaluronidase temporarily increases the permeability of subcutaneous tissue, enhancing trastuzumab's absorption.

Approved indications

• Adjuvant Treatment of HER2-Overexpressing Breast Cancer
• First-Line Treatment of HER2-Overexpressing Metastatic Breast Cancer
• Treatment of HER2-Overexpressing Metastatic Breast Cancer After Chemotherapy

Boxed warnings

• WARNING: CARDIOMYOPATHY, EMBRYO-FETAL TOXICITY, and PULMONARY TOXICITY WARNING: CARDIOMYOPATHY, EMBRYO-FETAL TOXICITY, and PULMONARY TOXICITY See full prescribing information for complete boxed warning. Cardiomyopathy: HERCEPTIN HYLECTA can result in subclinical and clinical cardiac failure manifesting as CHF, and decreased LVEF, with greatest risk when administered concurrently with anthracyclines. Evaluate cardiac function prior to and during treatment. Discontinue HERCEPTIN HYLECTA for cardiomyopathy. ( 2.4 , 5.1 ) Pulmonary Toxicity: Discontinue HERCEPTIN HYLECTA for anaphylaxis, angioedema, interstitial pneumonitis or acute respiratory distress syndrome. ( 5.3 ) Embryo-Fetal Toxicity: Exposure to HERCEPTIN HYLECTA during pregnancy can result in oligohydramnios, in some cases complicated by pulmonary hypoplasia and neonatal death. Advise patients of these risks and the need for effective contraception. ( 5.2 , 8.1 , 8.3 ) Cardiomyopathy HERCEPTIN HYLECTA administration can result in sub - clinical and clinical cardiac failure. The incidence and severity was highest in patients receiving HERCEPTIN HYLECTA with anthracycline - containing chemotherapy regimens. Evaluate left ventricular function in all patients prior to and during treatment with HERCEPTIN HYLECTA. Discontinue HERCEPTIN HYLECTA treatment in patients receiving adjuvant therapy and withhold HERCEPTIN HYLECTA in patients with metastatic disease for clinically significant decrease in left ventricular function [see Dosage and Administration (2.4) and Warnings and Precautions (5.1) ]. Pulmonary Toxicity HERCEPTIN HYLECTA administration can result in serious and fatal pulmonary toxicity. Symptoms usually occur during or within 24 hours of HERCEPTIN HYLECTA administration. Discontinue HERCEPTIN HYLECTA for anaphylaxis, angioedema, interstitial pneumonitis, or acute respiratory distress syndrome [see Warnings and Precautions (5.3 , 5.5) ] . Monitor patients until symptoms completely resolve. Embryo-Fetal Toxicity Exposure to HERCEPTIN HYLECTA during pregnancy can result in oligohydramnios and oligohydramnios sequence manifesting as pulmonary hypoplasia, skeletal abnormalities, and neonatal death. Advise patients of these risks and the need for effective contraception [see Warnings and Precautions (5.2) and Use in Specific Populations (8.1 , 8.3) ].

Common side effects

• alopecia
• nausea
• ARRs
• neutropenia
• diarrhea
• asthenia
• fatigue
• vomiting
• myalgia
• decreased appetite
• stomatitis
• arthralgia

Drug interactions

• Anthracyclines

Key clinical trials

• Testing the Addition of Herceptin Hylecta or Phesgo to the Usual Chemotherapy for HER2 Positive Endometrial Serous Carcinoma or Carcinosarcoma (PHASE3)
• A Single-arm Phase II Trial of SAcituzumab Govitecan and Trastuzumab for HER2+ Metastatic Breast Cancer After Trastuzumab dEruxtEcaN (SATEEN) (PHASE2)
• The SAPPHO Study: Sequential Therapy With Curative Intent in de Novo HER2+ Metastatic Breast Cancer (PHASE2)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Trastuzumab and Hyaluronidase-oysk CI brief — competitive landscape report
• Trastuzumab and Hyaluronidase-oysk updates RSS · CI watch RSS
• Adrienne G. Waks portfolio CI

Frequently asked questions about Trastuzumab and Hyaluronidase-oysk

Related

• Drug class: All Endoglycosidase [EPC] drugs
• Target: All drugs targeting HER2
• Manufacturer: Adrienne G. Waks — full pipeline
• Indication: Drugs for Adjuvant Treatment of HER2-Overexpressing Breast Cancer
• Indication: Drugs for First-Line Treatment of HER2-Overexpressing Metastatic Breast Cancer
• Indication: Drugs for Treatment of HER2-Overexpressing Metastatic Breast Cancer After Chemotherapy
• Also known as: Herceptin Hylecta
• Compare: Trastuzumab and Hyaluronidase-oysk vs similar drugs
• Pricing: Trastuzumab and Hyaluronidase-oysk cost, discount & access