Double-blind, placebo-controlled, multicenter, randomized, phase IIb neoadjuvant study of letrozole-lapatinib in postmenopausal hormone receptor-positive, human epidermal growth factor receptor 2-negative, operable breast cancer.

PURPOSE: This is a randomized, double-blind, placebo-controlled study aimed to evaluate the clinical and biologic effects of letrozole plus lapatinib or placebo as neoadjuvant therapy in hormone receptor (HR) -positive/human epidermal growth factor receptor 2 (HER2) -negative operable breast cancer. METHODS: Ninety-two postmenopausal women with stage II to IIIA primary breast cancer were randomly assigned to preoperative therapy consisting of 6 months of letrozole 2.5 mg orally daily plus lapatinib 1,500 mg orally daily or placebo. Surgery was performed within 2 weeks from the last study medication. Clinical response was assessed by ultrasonography. Pre- and post-treatment samples were evaluated for selected biomarkers. Fresh-frozen tissue samples were collected for genomic analyses. RESULTS: Numerically similar clinical response rates (partial + complete response) were observed (70% for letrozole-lapatinib and 63% for letrozole-placebo). Toxicities were generally mild and manageable. A significant decrease in Ki-67 and pAKT expression from baseline to surgery was observed in both arms. Overall, 34 patients (37%) had a mutation in PIK3CA exon 9 or 20. In the letrozole-lapatinib arm, the probability of achieving a clinical response was significantly higher in the presence of PIK3CA mutation (objective response rate, 93% v 63% in PIK3CA wild type; P = .040). CONCLUSION: The combination of letrozole-lapatinib in early breast cancer was feasible, with expected and manageable toxicities. In unselected estrogen receptor-positive/HER2-negative patients, letrozole-lapatinib and letrozole-placebo resulted in a similar overall clinical response rate and similar effect on Ki-67 and pAKT. Our secondary end point findings of a significant correlation between PIK3CA mutation and response to letrozole-lapatinib in HR-positive/HER2-negative early breast cancer must now be independently confirmed.

Phase I study of lapatinib in combination with chemoradiation in patients with locally advanced squamous cell carcinoma of the head and neck.

PURPOSE: This study (EGF100262) sought to establish the recommended phase II dose of lapatinib with chemoradiotherapy in patients with locally advanced squamous cell carcinoma of the head and neck (LA SCCHN). PATIENTS AND METHODS: Patients were enrolled onto cohorts of escalating lapatinib dose (500, 1,000, and 1,500 mg/d). Patients received 1 week of lapatinib alone followed by 6.5 to 7 weeks of the same dose of lapatinib plus radiotherapy 66 to 70 Gy and cisplatin 100 mg/m(2) on days 1, 22, and 43 of radiotherapy. End points included safety/tolerability and clinical activity. RESULTS: Thirty-one patients were enrolled (seven patients in each of the 500- and 1,000-mg cohorts and three in the 1,500-mg cohort; an additional 14 patients were enrolled at 1,500 mg in a safety cohort). Dose-limiting toxicities (DLTs) included perforated ulcer in one patient in the 500-mg cohort and transient elevation of liver enzymes in one patient in the 1,000-mg cohort. No DLTs were observed in the 1,500-mg cohort. Therefore, the recommended phase II dose was defined as lapatinib 1,500 mg/d with chemoradiotherapy. The most common grade 3 to 4 adverse events were radiation mucositis, radiation dermatitis, lymphopenia, and neutropenia. No patients experienced drug-related symptomatic cardiotoxicity, and no interstitial pneumonitis was reported. The overall response rate was 81% (65% at the recommended phase II dose). CONCLUSION: The recommended phase II dose is lapatinib 1,500 mg/d with chemoradiotherapy in patients with LA SCCHN; this regimen is associated with an acceptable tolerability profile. Given these findings, randomized phase II and III studies of lapatinib plus chemoradiotherapy have been initiated.