Safety, tolerability, and pharmacokinetics (PK) of rilotumumab in Japanese patients (pts) with advanced solid tumors.

Abstract

130 Background: Rilotumumab (R) is an investigational, fully human monoclonal antibody to hepatocyte growth factor/scatter factor, the only known MET receptor ligand. The MET pathway has been identified as a potentially useful target for therapeutic blockade in oncology. R has been studied in multiple phase 2 trials either as monotherapy or combination therapy, including a phase 2 trial in gastric cancer combining R with epirubicin, cisplatin, and capecitabine. A phase 1 study was done to evaluate the safety, tolerability, and PK of R in Japanese pts. Methods: An open-label, dose-escalation study was performed with R at 10 mg/kg (Cohort 1A), escalating to 20 mg/kg (Cohort 1B) if no dose-limiting toxicities (DLTs) were observed. Key eligibility criteria were Japanese pts with unresectable locally advanced or metastatic carcinoma, age ≥ 20 yr, ECOG ≤ 1, and refractory to standard treatment (tx). Pts received R as an intravenous infusion on days 1 and 15 of each 28-day cycle, except for cycle 1 in which the day 15 dose was skipped to facilitate PK analysis. DLTs were evaluated in cycle 1. Results: A total of 9 pts were enrolled (1A, n = 3; 1B, n = 6). No DLTs were noted. As of 17 April 13, tx-emergent AEs were reported in 89% of pts. Tx-emergent AEs occurring in > 1 pt overall were vomiting (33%), diarrhea (22%), decreased hemoglobin (22%), hypoalbuminemia (22%), and nausea (22%). One grade 3 tx-emergent AE was observed (decreased hemoglobin; 10 mg/kg). Tx-related AEs were reported in 56% of pts. One grade ≥ 2 tx-related AE was observed (hypoalbuminemia; 20 mg/kg). 8 pts discontinued R due to disease progression; 1 pt remained on the investigational product. Mean exposure of R (Cmax and AUC) appeared to be doubled as dose increased from 10 to 20 mg/kg. The estimated mean CL was approximately 0.2 mL/hr/kg in both cohorts, suggesting a linear PK from 10 to 20 mg/kg. The terminal half-life of R was about 15 days. Conclusions: R monotherapy had an acceptable safety profile in Japanese pts with advanced solid tumors. These phase 1 safety and PK data support the further evaluation of R combined with chemotherapy in Japanese pts with MET-positive metastatic gastric cancer. Clinical trial information: NCT01791374.