PURPOSE: The pharmacology, pharmacokinetics, clinical efficacy, safety, and 
administration of pertuzumab in patients with metastatic human epidermal growth 
factor receptor type 2 (HER2)-positive breast cancer are reviewed.
SUMMARY: Disease progression in HER2-positive breast cancer is often due to 
resistance to or a lack of efficacy of trastuzumab-based anti-HER2 therapy. 
Pertuzumab is the first humanized monoclonal antibody in a new class of drugs, 
the HER dimerization inhibitors, approved by the Food and Drug Administration 
for the first-line treatment of patients with metastatic HER2-positive breast 
cancer who have not received prior anti-HER2 therapy or chemotherapy for 
metastatic disease. Since pertuzumab binds to a different epitope than 
trastuzumab, combination therapy with pertuzumab and trastuzumab results in a 
more complete blockade of HER2 signaling than trastuzumab monotherapy. The 
efficacy of adding pertuzumab to trastuzumab-docetaxel dual therapy was 
demonstrated in a pivotal randomized multicenter Phase III trial, which showed a 
significant benefit in terms of progression-free survival, with improved overall 
survival, in favor of the triple therapy as an initial regimen in 
treatment-naive patients with metastatic HER2-positive breast cancer. The 
combination of pertuzumab and trastuzumab has been found to have a tolerable 
toxicity profile. As clinical trials of pertuzumab for adjuvant, neoadjuvant, 
and metastatic-disease treatment continue, its role in the treatment of 
HER2-positive breast cancer will continue to evolve.
CONCLUSION: Pertuzumab, a novel HER2 dimerization inhibitor, has been shown to 
be effective in the treatment of metastatic HER2-positive breast cancer when 
used in combination with trastuzumab and docetaxel and is recommended for 
first-line therapy.