Medical uses
The fixed-dose combination is indicated for the treatment of early breast cancer (EBC):

Use in combination with chemotherapy for:the neoadjuvant treatment of adults with HER2-positive, locally advanced, inflammatory, or early stage breast cancer (either greater than two cm in diameter or node positive) as part of a complete treatment regimen for early breast cancer;
the adjuvant treatment of adults with HER2-positive early breast cancer at high risk of recurrence.and for the treatment of metastatic breast cancer (MBC):

Use in combination with docetaxel for the treatment of adults with HER2-positive metastatic breast cancer (MBC) who have not received prior anti-HER2 therapy or chemotherapy for metastatic disease. Adverse effects
The FDA label includes a boxed warning about the risk of potential heart failure, fetal harm, and lung toxicity. History
The fixed-dose combination of pertuzumab, trastuzumab, and hyaluronidase was approved for medical use in the United States in June 2020.The FDAs approval was based on the results of a non-inferiority study in participants with HER2-positive early breast cancer, which demonstrated the fixed-dose combination of pertuzumab, trastuzumab, and hyaluronidase had comparable efficacy and safety as IV pertuzumab and IV trastuzumab, except for administration-related reactions, which were higher with the fixed-dose combination due to the subcutaneous route of administration.Efficacy was investigated in FeDeriCa (NCT03493854), an open-label, multicenter, randomized trial enrolling 500 participants with operable or locally advanced HER2-positive breast cancer.
Clinical trial number NCT03493854 for "A Study to Evaluate the Pharmacokinetics, Efficacy, and Safety of Subcutaneous Administration of the Fixed-Dose Combination of Pertuzumab and Trastuzumab in Combination With Chemotherapy in Participants With HER2-Positive Early Breast Cancer (FeDeriCa)" at ClinicalTrials.gov