Pertuzumab in Breast Cancer: A Systematic Review

A Rare Case of Pertuzumab-Induced Toxic Epidermal Necrolysis

Pertuzumab is a targeted therapy drug that is employed in the management of human epidermal growth factor receptor 2 (HER2)-positive breast cancer and works by blocking the ability of cancer cells to receive growth and proliferation signals. Toxic epidermal necrolysis (TEN) is a severe cutaneous manifestation characterized by widespread erythema, necrosis, and bullous detachment of the skin involving more than 10% of the body surface area (BSA) and may be precipitated by an immunologic response to the administration of certain medications. However, TEN development as a consequence of HER2 inhibitor therapy has not been described in the existing literature. A 44-year-old female with a history of metastatic breast cancer to the liver presented with a diffuse blistering rash following a first-time administration of pertuzumab three days prior. Her rash began as painful and pruritic blisters 12 hours after the last infusion of pertuzumab and progressed to involve her arms, chest, groin, and thighs with a positive Nikolsky sign. She was managed supportively with high-dose steroids and antihistamines, and although her hospital course was complicated by hypotension requiring pressor support, she gradually made a full recovery and was released to a rehabilitation facility.

Relationship between HER2 gene status and selected potential biological features related to trastuzumab resistance and its influence on survival of breast cancer patients undergoing trastuzumab adjuvant treatment

Background

The aim of the study was to investigate if parameters associated with human epidermal growth factor receptor type 2 (HER2) status (HER2 gene copy number, HER2/CEP17 ratio or polysomy of chromosome 17) are related to various biological features potentially responsible for trastuzumab resistance (PTEN, IGF-1R, MUC4, EGFR, HER3, HER4, and mutation status of PIK3CA) as well as their influence on survival of HER2-positive breast cancer patients treated with adjuvant chemotherapy and trastuzumab.

Patients and methods

The investigated group consisted of 117 patients with invasive ductal breast cancer (T≥1, N≥0, M0) with overexpression of HER2, who underwent radical surgery between 2007 and 2014. Status of ER, PR, and HER2 expression was retrieved from patients' files. HER2 gene copy number was investigated by fluorescence in situ hybridization using PathVysion HER-2 DNA Probe Kit II. Expression of PTEN, IGF-1R, MUC4, EGFR, HER3, and HER4 was assessed immunohistochemically on formalin-fixed paraffin-embedded tissue sections. PIK3C mutation status was determined by qPCR analysis.

Results

Overexpression of HER2 protein (IHC 3+) and ER negativity corresponded to higher HER22 copy number and HER2/CEP17 ratio (.<0.001). Tumors with polysomy were characterized by higher HER22 gene copy number but lower HER2/CEP17p ratio (p<0.026, p<0.001). Patients with tumors featuring HER3 immunonegativity or low HER2/CEP17 ratio (#4) were characterized by 100% metastasis-free survival (.=0.018, p=0.062).

Conclusion

Presence of both unfavorable factors, ie, HER3 expression and high HER2/CEP17 ratio, allowed to distinguish a group of patients with worse prognosis (.=0.001).

Monitoring Trastuzumab Resistance and Cardiotoxicity: A Tale of Personalized Medicine

While approval of trastuzumab, a recombinant monoclonal antibody directed against HER2, along with a diagnostic kit to detect breast cancers which are positive for HER2 overexpression, has advanced a new era of stratified and personalized medicine, it also created several challenges to our scientific and clinical practice. These problems include trastuzumab resistance and trastuzumab-induced cardiotoxicity. In this review, we will summarize data from the literature regarding mechanisms of trastuzumab resistance and trastuzumab-induced cardiotoxicity and present some promising model systems that may advance our understanding of these mechanisms. Our discussion will include development of circulating tumor cells and circulating tumor DNA for monitoring tumor burden, of patient-derived xenograft models for preclinical testing of novel therapies, and of novel therapeutic strategies for trastuzumab-resistance and possible integration of these strategies in the design of co-clinical studies for testing in relevant patient subpopulations.

Pertuzumab in combination with trastuzumab and docetaxel for HER2-positive metastatic breast cancer

Overexpression of HER2 - found in approximately 15-20% of all breast cancers - is a negative prognostic factor. Although trastuzumab significantly improves the prognosis of HER2-positive breast cancer, half of the patients with metastatic breast cancer experience disease progression within 1 year. Pertuzumab is a novel HER2-targeted humanized monoclonal antibody that binds to the dimerization domain of HER2 and acts synergically with trastuzumab in inhibiting tumor progression. The CLEOPATRA trial demonstrated that adding pertuzumab to trastuzumab plus docetaxel significantly prolonged progression-free survival and overall survival without increasing severe adverse events. Conclusively, pertuzumab was approved by the US FDA in June 2012 for use in combination with trastuzumab and docetaxel for the treatment of patients with HER2-positive metastatic breast cancer. Furthermore, various clinical trials to evaluate the efficacy and safety of pertuzumab combined with other cytotoxic agents are ongoing at present. Thus, pertuzumab has been becoming important for the treatment of patients with HER2-positive metastatic breast cancer.

Pertuzumab in Combination with Trastuzumab and Chemotherapy in the Treatment of HER2-Positive Metastatic Breast Cancer: Safety, Efficacy, and Progression Free Survival

Tyrosine kinase inhibitors have revolutionized the oncology community and were pioneered by the use in HER2-targeted therapies. Improved outcomes were seen with the advent of trastuzumab, leading investigators to develop newer agents to target the HER2 pathway such as the novel monoclonal antibody pertuzumab. In this paper, we describe the attributes of pertuzumab including: mechanism of action, pharmacokinetics and metabolism, safety/cardiotoxicity, drug interactions, efficacy, and role in HER2-positive breast cancer management. Newly reviewed here versus previously published reviews on pertuzumab oriented therapy are data of pertuzumab monotherapy as it is used in combination with other anti-HER2 agents derived from preclinical research and ongoing clinical trials.