Blueprint Medicines announced updated data from its ongoing Phase 1 clinical trial of BLU-554, a potent and highly selective inhibitor of fibroblast growth factor receptor 4 (FGFR4) for the treatment of patients with advanced hepatocellular carcinoma (HCC). As of a data cutoff date of August 18, 2017, BLU-554 demonstrated a 16 percent objective response rate (ORR) in patients with FGFR4-driven HCC. In addition, 49 percent of patients with FGFR4-driven HCC had radiographic tumor reduction. BLU-554 was well-tolerated and most adverse events (AEs) reported by investigators were Grade 1 or 2.
"Patients with hepatocellular carcinoma face a very poor prognosis with few therapeutic options," said Richard Kim, M.D., Associate Professor, Moffit Cancer Center, an investigator for the study. "The new BLU-554 data announced today show that in heavily pre-treated patients, BLU-554 demonstrated encouraging clinical activity, with approximately half of patients with FGFR4-driven HCC having tumor shrinkage. These data compare well to historical data for currently approved agents showing response rates of approximately 10 percent or less, and BLU-554 has the potential to change the treatment paradigm for patients with FGFR4-driven HCC."
BLU-554 is currently being evaluated in a Phase 1 clinical trial in patients with advanced HCC. Following the completion of the dose escalation portion of the trial and determination of the maximum tolerated dose (MTD) of 600 mg once daily (QD), Blueprint Medicines initiated the expansion portion of the trial.
As of the data cutoff of August 18, 2017, 77 patients had been treated with BLU-554 in the dose escalation and expansion portions of the Phase 1 clinical trial at five dose levels (ranging from 140 mg QD to 900 mg QD), including 44 patients with FGFR4-driven HCC. FGFR4-driven HCC was defined as at least one percent tumor expression of FGF19, the FGFR4 ligand, as measured by an immunohistochemistry (IHC) assay. In general, the enrolled population was heavily pretreated: 82 percent received prior tyrosine kinase inhibitor (TKI) treatment, 23 percent received prior immunotherapy, and 91 percent received prior systemic therapy.
Pharmacokinetic (PK) analysis demonstrated rapid oral absorption across all dose levels, with a mean half-life of approximately 17 hours and exposure in the expected therapeutic range based on HCC xenograft models. Collectively, these data support a once-daily dosing regimen.