Exploratory Studies
PD, tumor, MPS
TUMOR, BONE METASTASES
There were 44 samples of archival tissue available for PD-L1 testing, 40 of which (90.9%) were interpretable and four samples which did not have tumor in the specimen. Of the 40 evaluable samples, 32 (80.0%) had PD-L1 tumor MPS ≥ 1. The ORR was 69% in patients with PD-L1–positive samples and 50% in patients with PD-L1–negative samples. The median MPS of patients with an objective response was 2.5 (range, 0–100) as compared with 10 (range, 0–85) in patients without a treatment response. Two patients with PD had MPS of 20 and 70. The patient with CR had MPS 40.Twenty-three of 26 patients with bone metastases had bone turnover markers collected at baseline. Very few patients had elevated bone turnover markers at baseline: 1 for beta-cross-linked C-terminal telopeptide (β-CTX; 4.3%), 3 for BS-ALP (13.0%), and 3 for P1NP (13.0%). The ORR in patients with bone metastases was 38.5%. At the time of the first on-treatment scans at 9 weeks, P1NP had decreased in all patients regardless of treatment response. Among patients with PD (2 patients) or a PR (6 patients) who had bone turnover markers collected at baseline and at 9 weeks, change in β-CTX and BS-ALP was concordant with radiographic response in 71.4% and 62.5% patients, respectively.