FDA Approves Novel Interchangeable Biosimilar for Pertuzumab in HER2+ Breast Cancer

The FDA has granted approval for pertuzumab-dpzb (Poherdy), designating it as the first interchangeable biosimilar to the reference product pertuzumab (Perjeta).¹ This significant regulatory action provides clinicians with a crucial new treatment option for patients diagnosed with HER2-positive breast cancer across multiple disease settings, enhancing therapeutic accessibility and potentially mitigating drug cost burdens within oncology care.

As an interchangeable biosimilar, pertuzumab-dpzb is structurally and functionally highly similar to the reference product and demonstrates no clinically meaningful differences in terms of safety, purity, and potency. Crucially, the interchangeability designation means that the biosimilar may be substituted for the reference product without consultation with the prescribing clinician, subject to state pharmacy laws. This determination was based on the comprehensive "totality of the evidence" approach mandated by the FDA, including extensive analytical characterization, human pharmacokinetic (PK) and pharmacodynamic (PD) studies, clinical immunogenicity data, and comparative clinical efficacy results.

Clinical Indications and Dosing Regimen

The approved indications for pertuzumab-dpzb mirror those of the reference product, encompassing both metastatic and early-stage disease, in combination with trastuzumab (Herceptin) and chemotherapy.

Metastatic Breast Cancer (MBC)

Pertuzumab-dpzb is indicated for use in combination with trastuzumab and docetaxel for the treatment of adults with HER2-positive MBC who have not received prior anti-HER2 therapy or chemotherapy for metastatic disease. This regimen established the current standard of care for first-line HER2-positive MBC based on the pivotal efficacy and overall survival data derived from the CLEOPATRA trial (NCT00567190).²

Early Breast Cancer (EBC)

The biosimilar is also approved for:

1. Neoadjuvant treatment: In combination with trastuzumab and chemotherapy for adults with HER2-positive, locally advanced, inflammatory, or early-stage breast cancer (tumor diameter >2 cm or node-positive disease). This treatment is administered as part of a complete regimen for early breast cancer.
2. Adjuvant treatment: In combination with trastuzumab and chemotherapy for adults with HER2-positive EBC at high risk of recurrence. The high-risk definition typically aligns with patients enrolled in landmark trials such as APHINITY (NCT01358877).³

The recommended dosing for pertuzumab-dpzb remains consistent with the established regimen for pertuzumab: an initial loading dose of 840 mg administered as a 60-minute intravenous (IV) infusion, followed by a maintenance dose of 420 mg administered every 3 weeks thereafter, as a 30- to 60-minute IV infusion. The concurrent administration of trastuzumab and chemotherapy should adhere to established clinical guidelines and protocols specific to the disease setting.¹

Safety Profile Considerations for Clinicians

The safety profile of pertuzumab-dpzb is consistent with that of the reference product. Clinicians should remain vigilant regarding the following safety information:

• Boxed warnings: The labeling for pertuzumab and pertuzumab-dpzb carries boxed warnings for left ventricular dysfunction, including congestive heart failure, and embryo-fetal toxicity. Given the cardiac risk, patients must undergo comprehensive baseline and periodic assessments of left ventricular ejection fraction during and after treatment.
• Other warnings and precautions: Patients should be monitored for infusion-related reactions and hypersensitivity reactions/anaphylaxis, which may necessitate treatment interruption, dosage reduction, or permanent discontinuation, depending on severity.

REFERENCES

1. FDA approves new interchangeable biosimilar for Perjeta. US FDA. November 13, 2025. Accessed November 13, 2025. https://tinyurl.com/3ny7pssd

2. A study to evaluate pertuzumab + trastuzumab + docetaxel vs. placebo + trastuzumab + docetaxel in previously untreated HER2-positive metastatic breast cancer (CLEOPATRA). ClinicalTrials.gov. Accessed November 13, 2025. https://clinicaltrials.gov/study/NCT00567190

3. A study of pertuzumab in addition to chemotherapy and trastuzumab as adjuvant therapy in participants with human epidermal growth receptor 2 (HER2)-positive primary breast cancer (APHINITY). ClinicalTrials.gov. Accessed November 13, 2025. https://www.clinicaltrials.gov/study/NCT01358877