Therapeutic Response Statement (Sensitivity)
This therapeutic response statement supports the relationship that ER positive, ERBB2 amplification, PR positive status confers therapeutic sensitivity to Lapatinib, Letrozole in patients with Invasive Breast Carcinoma.
The European Medicines Agency (EMA) has authorized laplatinib in combination with an aromatase inhibitor for postmenopausal women with hormone receptor positive metastatic disease, not currently intended for chemotherapy. This indication states that the patients in the registration study were not previosuly treated with trastuzumab or an aromatase inhibitor and that no data are available on the efficacy of this combination relative to trastuzumab in combination with an aromatase inhibitor in this patient population. This indication is based on the randomized, double-blind, and placebo controlled phase 3 study EGF30008, which used Letrozole as an aromatase inhibitor. Lapatinib's product information sheet further defines HER2 (ErbB2) overexpressing tumors as IHC3+, or IHC2+ with gene amplification or gene amplification alone.
This statement is based on a regulatory approval from the European Medicines Agency:
Tyverb is indicated for the treatment of adult patients with breast cancer, whose tumours overexpress HER2 (ErbB2) in combination with an aromatase inhibitor for postmenopausal women with hormone receptor positive metastatic disease, not currently intended for chemotherapy. The patients in the registration study were not previously treated with trastuzumab or an aromatase inhibitor. No data are available on the efficacy of this combination relative to trastuzumab in combination with an aromatase inhibitor in this patient population.