Characterization of infections and hypogammaglobulinemia treated with the combination of pertuzumab and trastuzumab

PURPOSE: We update a patient series that reported a high incidence of infection with Gram-positive cocci in women treated with the combination of pertuzumab and trastuzumab and further characterize this clinical problem. PATIENTS: Treating physicians and advanced practice partners identified women who developed infections while on treatment with pertuzumab and trastuzumab alone or in combination with chemotherapy and enrolled them onto this registry trial. RESULTS: Between March, 2014 and May, 2017, 48 patients with HER2-positive breast cancers were reported to have 59 individual infections. The median age was 48 years. Twenty-four patients received neoadjuvant therapy, 17 were treated for metastatic disease, and 7 were treated in the adjuvant setting. Pertuzumab and trastuzumab were combined with carboplatin and docetaxel in 24 (49%) patients, docetaxel in 10 (21%), nab-paclitaxel in 12 (24%), and without other agents in 2 (4%). Granulocyte growth factors were administered in 24 (49%) patients and no patients were documented to be neutropenic. Folliculitis developed in 25 (52%) patients and was counted as a single infection. Abscesses developed at a number of sites in 24 (49%) patients, including a septic knee requiring total knee replacement. Paronychia occurred in 7 (15%) patients, and 5 (10%) developed cellulitis. When cultures were obtained, Gram-positive cocci were consistently identified. Hypogammaglobulinemia was documented in 14 (36%) of the 33 patients tested. CONCLUSIONS: Our data continue to support an increased risk of infections with Gram-positive cocci as a potentially serious adverse event in women treated with pertuzumab and trastuzumab.