Pembrolizumab in Patients With Metastatic Breast Cancer With High Tumor Mutational Burden: Results From the Targeted Agent and Profiling Utilization Registry (TAPUR) Study.

PURPOSE: The TAPUR Study is a phase II basket trial that aims to identify signals of antitumor activity of commercially available targeted agents in patients with advanced cancers harboring genomic alterations known to be drug targets. Results in a cohort of patients with metastatic breast cancer (mBC) with high tumor mutational burden (HTMB) treated with pembrolizumab are reported. METHODS: Patients with advanced mBC received standard doses of either 2 mg/kg or 200 mg infusions of pembrolizumab every 3 weeks. Simon's two-stage design was used with a primary study end point of disease control (DC) defined as objective response or stable disease of at least 16 weeks duration. If two or more patients in stage I achieved DC, the cohort would enroll 18 additional patients in stage II. Secondary end points include progression-free survival (PFS), overall survival, and safety. RESULTS: Twenty-eight patients were enrolled from October 2016 to July 2018. All patients' tumors had HTMB ranging from 9 to 37 mutations/megabase. DC and objective response were noted in 37% (95% CI, 21 to 50) and 21% of patients (95% CI, 8 to 41), respectively. Median PFS was 10.6 weeks (95% CI, 7.7 to 21.1); median overall survival was 30.6 weeks (95% CI, 18.3 to 103.3). No relationship was observed between PFS and tumor mutational burden. Five patients experienced ≥ 1 serious adverse event or grade 3 adverse event at least possibly related to pembrolizumab consistent with the product label. CONCLUSION: Pembrolizumab monotherapy has antitumor activity in heavily pretreated patients with mBC characterized by HTMB. Our findings support the recent US Food and Drug Administration approval of pembrolizumab for treatment of patients with unresectable or metastatic solid tumors with HTMB without alternative treatment options.

Cetuximab in Patients with Breast Cancer, Non-Small Cell Lung Cancer, and Ovarian Cancer Without KRAS, NRAS, or BRAF Mutations: Results from the Targeted Agent and Profiling Utilization Registry (TAPUR) Study.

BACKGROUND: The Targeted Agent and Profiling Utilization Registry (TAPUR) Study, a phase II basket study, evaluates anti-tumor activity of commercially available targeted agents in patients with advanced cancers harboring genomic alterations known as drug targets. OBJECTIVE: With no known genomic targets predictive of sensitivity to cetuximab, cetuximab was evaluated in patients with breast cancer (BC), non-small cell lung cancer (NSCLC), and ovarian cancer (OC), without KRAS, NRAS, or BRAF mutations. PATIENTS AND METHODS: Eligible patients with advanced BC, NSCLC, and OC received a cetuximab loading dose, then weekly infusions (250 mg/m2 over 60 min). A Simon two-stage design, requiring ten patients in stage I, was employed per each disease-specific cohort. The primary endpoint was disease control (objective response or stable disease for at least 16 weeks). If two or more patients in stage I achieved disease control, the cohort would enroll 18 more patients in stage II. Power and alpha of the design are 85% and 10%, respectively. Secondary endpoints included progression-free survival, overall survival, and safety. RESULTS: Patients with BC (n = 10), NSCLC (n = 10), and OC (n = 29) were enrolled between June 2016 and September 2018. No objective responses or stable disease for at least 16 weeks were observed in the BC and NSCLC cohorts. No objective responses and four patients with stable disease for at least 16 weeks were observed in the OC cohort. Six of 49 patients reported grade 3 or higher adverse events or serious adverse events at least possibly related to cetuximab. CONCLUSIONS: Cetuximab does not have clinical activity in patients with advanced BC, NSCLC, and OC without KRAS, NRAS, or BRAF mutations. CLINICAL TRIAL REGISTRATION: NCT02693535 (26 February, 2016).