The US FDA has approved pertuzumab-dpzb (Poherdy, Shanghai Henlius Biologics Co. Ltd.) as the first interchangeable biosimilar to the breast cancer drug pertuzumab.

Like pertuzumab (Perjeta, Genentech Inc.), the new biosimilar agent is a HER2 antagonist indicated as part of treatment combinations for certain patients with HER2-positive breast cancer, according to the FDA approval notice.

Specifically, pertuzumab-dpzb is approved to be used interchangeably with pertuzumab in combination with trastuzumab and docetaxel for adults with HER2-positive metastatic breast cancer who have not been previously treated with anti-HER2 therapy or chemotherapy for metastatic disease and in combination with chemotherapy in two earlier disease settings.

These include neoadjuvant treatment of adults with HER2-positive locally advanced, inflammatory, or early-stage breast cancer when used as part of a complete treatment regimen for early breast cancer, and adjuvant treatment of adults with HER2-positive early breast cancer with a high risk for recurrence.

Approval was based on multiple “comparisons across a broad range of structural and functional product quality attributes, including those known to impact safety and efficacy, human pharmacokinetic data, clinical immunogenicity data, and supportive clinical data in patients with breast cancer,” the FDA notice states.

The studies included a phase 1 randomized study comparing the safety and immunogenicity of pertuzumab and pertuzumab-dpzb in healthy subjects and a phase 3 clinical study comparing the safety and efficacy of the two agents as a neoadjuvant therapy in patients with HER2-positive, hormone receptor-negative early or locally advanced breast cancer, the drug maker noted in a press release.

According to the full prescribing information to be posted on Drugs@FDA, the recommended initial pertuzumab-dpzb dose is 840 mg given as a 60-minute intravenous infusion, followed every 3 weeks by a 420-mg dose given as a 30- to 60-minute intravenous infusion. 

The prescribing information includes a boxed warning for left ventricular dysfunction and embryo-fetal toxicity, as well as warnings and precautions for infusion-related reactions and hypersensitivity reactions or anaphylaxis. 

Sharon Worcester, MA, is an award-winning medical journalist based in Birmingham, Alabama, writing for Medscape Medical News, MDedge, and other affiliate sites. She currently covers oncology, but she has also written on a variety of other medical specialties and healthcare topics. She can be reached at sworcester@mdedge.com or on X @SW_MedReporter.