A Phase II Single-arm Study of Palbociclib in Patients With HER2-positive Breast Cancer With Brain Metastases and Analysis of ctDNA in Patients With Active Brain Metastases.

INTRODUCTION: Palbociclib is highly efficacious and well tolerated in hormone-receptor positive (HR+) metastatic breast cancer (BC) but its activity for HER2+ BC with brain metastases (BM) is unknown. METHODS: In a single-arm phase II study we evaluated palbociclib with trastuzumab for patients with HER2+ MBC and BM. The primary endpoint was BM response rate. Circulating tumor DNA (ctDNA) was evaluated at baseline, and in a subset of patients at cycle 3 and progression. We also retrospectively identified additional patients with metastatic BC, active BM, and a ctDNA assessment prior to therapy for BM. RESULTS: Twelve patients with HER2+ MBC were enrolled, 4 with HR+ and 8 with HR- disease. No responses were seen. Best response was stable disease for 6 patients and progressive disease for 6 patients. The median PFS was 2.2 months, interquartile range (IQR) was 1.56 to 3.63 months. The median OS was 13.1 months and IQR was 9.4 to 23.8 months The CNS was the primary site of progression for all patients. The median variant allele fraction (VAF) of the dominant variant in each patient was 0.18% (interquartile range [IQR] 0.12%-0.47%) with a median number of somatic alterations of 1. We additionally evaluated ctDNA results from 26 patients with BC and active BM, among whom the median VAF was 11.8% (IQR 3.9%-27.3%) with a median number of alterations was 6 (IQR 4-9). Notably, progressive systemic disease was significantly less frequent in the trial cohort compared with additional retrospectively identified patients (8% vs. 81%). CONCLUSION: Palbociclib did not demonstrate activity in HER2+ MBC with BM. Patients with progressive BM but stable, responding, or absent systemic disease have low VAF and number of alterations detected by ctDNA analysis from blood.

Gemcitabine with or without docetaxel and resection for recurrent osteosarcoma: the experience at Children's Memorial Hospital.

It remains unclear how to optimally incorporate gemcitabine and docetaxel into the management of patients with recurrent osteosarcoma. We describe 4 pediatric patients with recurrent osteosarcoma who were treated with gemcitabine ± docetaxel and resection. One patient had a partial response and 2 had stable disease. Two patients subsequently underwent surgical resections. Median duration of response was 8 months and was longer for patients who underwent resection. One patient remains disease-free 57 months from recurrence. Our limited series provides additional support for the use of gemcitabine ± docetaxel for recurrent osteosarcoma and suggests benefit of concurrent local control measures if possible.