Blueprint's candidate for advanced liver cancer shows anti-tumor activity in early-stage study but with side effects; shares down 9%

|About: Blueprint Medicines (BPMC)|By:, SA News Editor

Results from a proof-of-concept Phase 1 trial assessing Blueprint Medicines' (BPMC -8.6%) BLU-554 in patients with advanced hepatocellular carcinoma (HCC) showed anti-tumor activity albeit with side effects. The data are being presented today at the 28th EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics in Munich, Germany.

BLU-554 was evaluated in the dose escalation stage of the study. As of the November 7 data cutoff date, 25 HCC patients received five dose levels (140 mg once daily to 900 mg once daily). Most patients had been previously treated with sorafenib [Bayer's (OTCPK:BAYRY) NEXAVAR].

One patient had a confirmed partial response (PR) while 12 had stable disease implying a disease control rate of 52% (n=13/25).

Of the 10 evaluable patients with FGF19 overexpression, five showed radiographic tumor reduction including on confirmed PR.

72% of patients (n=18/25) discontinued treatment due to cancer progression (n=15), treatment-related adverse events (n=2) and investigator's decision (n=1).

The most common adverse events (AEs) were diarrhea (72%), nausea (44%), abdominal pain (40%), vomiting (40%), fatigue (36%) and elevated liver enzymes (32%, 28%). Serious AEs occurring in three or more patients included anemia, elevated liver enzymes, abdominal pain and decreased lymphocytes. Two patients experienced dose-limited toxicities at 900 mg which then defined 600 mg as the maximum tolerated dose.

Enrollment in a 45-subject expansion phase is underway.

BLU-554 inhibits a protein called fibroblast growth factor receptor 4 (FGFR4). Investigators measured the levels of the protein FGF19 because it activates the FGFR4 pathway.