The FDA has approved pertuzumab-dpzb (Poherdy) as the first interchangeable biosimilar to pertuzumab (Perjeta), marking a significant regulatory milestone that provides clinicians with a new treatment option for patients with HER2-positive breast cancer. This approval enhances therapeutic accessibility and potentially mitigates drug cost burdens within oncology care.
Interchangeability Designation and Clinical Implications
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. 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.
The FDA's determination was based on the comprehensive "totality of the evidence" approach, including extensive analytical characterization, human pharmacokinetic and pharmacodynamic studies, clinical immunogenicity data, and comparative clinical efficacy results. Comparisons across a range of structural and functional product quality attributes, such as those that impact safety and efficacy, pharmacokinetic data, clinical immunogenicity data, and supportive clinical data in patients with breast cancer, supported the biosimilar's similarity to reference pertuzumab.
Approved Indications
The approved indications for pertuzumab-dpzb mirror those of the reference product, encompassing both metastatic and early-stage disease settings:
Metastatic Breast Cancer
Pertuzumab-dpzb is indicated in combination with trastuzumab (Herceptin) and docetaxel in adult patients with HER2-positive metastatic breast cancer not previously treated with anti-HER2 therapy or chemotherapy for metastatic disease. This regimen established the current standard of care for first-line HER2-positive metastatic breast cancer based on the pivotal efficacy and overall survival data derived from the CLEOPATRA trial.
Early Breast Cancer
The biosimilar is approved for two early breast cancer settings:
Neoadjuvant treatment: In combination with trastuzumab and chemotherapy as neoadjuvant therapy for adults with HER2-positive, locally advanced, inflammatory, or early-stage breast cancer as part of a complete treatment regimen for early breast cancer.
Adjuvant treatment: In combination with trastuzumab and chemotherapy as adjuvant treatment for adult patients with HER2-positive early breast cancer at high risk of recurrence. The high-risk definition typically aligns with patients enrolled in landmark trials such as APHINITY.
Dosing and Administration
The recommended dosing for pertuzumab-dpzb remains consistent with the established regimen for pertuzumab. The recommended dose is 840 mg administered via a 60-minute intravenous infusion, followed every 3 weeks by 420 mg administered via a 30- to 60-minute intravenous infusion. The concurrent administration of trastuzumab and chemotherapy should adhere to established clinical guidelines and protocols specific to the disease setting.
Safety Profile and Monitoring Requirements
The safety profile of pertuzumab-dpzb is consistent with that of the reference product. The warning label includes a boxed warning for left ventricular dysfunction and embryo-fetal toxicity, and a warning for infusion-related reactions and hypersensitivity reactions/anaphylaxis.
Given the cardiac risk, patients must undergo comprehensive baseline and periodic assessments of left ventricular ejection fraction during and after treatment. Patients should also be monitored for infusion-related reactions and hypersensitivity reactions/anaphylaxis, which may necessitate treatment interruption, dosage reduction, or permanent discontinuation, depending on severity.
