Fixed-dose combination of pertuzumab and trastuzumab for subcutaneous injection in patients with HER2-positive breast cancer: A multidisciplinary approach

Pertuzumab plus trastuzumab, administered intravenously (IV) with chemotherapy, is standard treatment for HER2-positive metastatic or high-risk early breast cancer. Pertuzumab and trastuzumab are administered over 1-2.5 h traditionally; however, the need for IV infusions places a strain on medical centers with respect to scheduling, preparation, and administration. A novel fixed-dose combination of pertuzumab and trastuzumab for subcutaneous injection (PHESGO®, PH FDC SC) can be administered in approximately 5-8 min. PH FDC SC was non-inferior to IV pertuzumab plus trastuzumab in terms of pertuzumab and trastuzumab serum levels in the phase III FeDeriCa study, which enrolled 500 patients with HER2-positive early breast cancer. Total pathologic complete response rates were comparable after PH FDC SC (59.7%) or IV pertuzumab plus trastuzumab (59.5%), as was the incidence of grade ≥3 (48.8% vs 52.8%) and serious adverse events (16.1% vs 17.9%). The results of a phase II clinical trial (PHranceSCa) showed that a majority of patients (85%) preferred PH FDC SC treatment over IV pertuzumab plus trastuzumab. A US multicenter expanded access study (NCT04395508) is evaluating the safety of PH FDC SC administered at home by nurse providers in patients receiving maintenance HER2-targeted therapy every 3 weeks. This product takes much less time to administer than IV pertuzumab-trastuzumab and has the potential to alleviate time constraints for patients and busy clinics. In this review we provide an overview of PH FDC SC, and discuss our experience in preparing and administering this product to patients with HER2-positive breast cancer during clinical trials.