A first-in-human phase I study of ER-α36 modifier icaritin in patients with advanced solid tumors.

Abstract

2614 Background: ER-α36 was recently identified to be expressed in varieties of cancers and may play important roles in carcinogenesis and tumor progression. Icaritin, a natural prenylflavonoid derived from the Chinese herb Epimedium, is a first of its kind ER-α36 modifier, which demonstrated potent anti-tumor effect in multiple cancer cell lines and their xenograft models. This study aims to determine its safety, tolerability, pharmacokinetics (PK), and potential antitumor activity. Methods: This phase I study comprises phase Ia and Ib. In phase Ia part, patients with advanced breast cancer (ABC) were treated with escalating doses of Icaritin orally once daily on a continuous 28-day dosing schedule. In phase Ib part, dosing was fixed to 600 or 800mg twice daily and expansion was made to other selected malignancies including hepatocellular cancer (HCC), colorectal cancer (CRC) and intrahepatic cholangiocarcinoma (ICC) to further explore PK parameters and efficacy. Results: 24 patients were enrolled to receive Icaritin at six dose levels ranging from 50mg to 1600mg per day in phase Ia. No dose limited toxicity (DLT) was found even in the highest dose defined in the protocol, thus the maximum tolerated dose (MTD) was not reached. Only grade 1 drug-related adverse events were observed including neutropenia, ALT elevation, hypercholesteremia, fatigue, anorexia, hypertriglyceridemia, proteinuria, myalgia, hot flash and rash. PK data from the fed dosing showed 3-fold increase of Cmax and AUC compared with the fast dosing. Half life was around 2-7 hours. Among 22 evaluable subjects, no complete or partial response (CR or PR) was detected, 5 patients had stable disease(SD)for 3 months or longer. For phase Ib study, 24 patients had been enrolled. One ABC, 2 CRC and 3 ICC patients progressed after 2 months of medication. Among 7 HCC patients already evaluated, 1 obtained PR and progressed after one year of treatment and 2 remained in the study, stable for 5 months. Similar drug related toxicity profile was noted in phase Ib. Conclusions: Icaritin was generally well-tolerated without DLT across tested dose levels. Evidence of promising antitumor activity was observed in ABC and HCC. Final results will be presented at the meeting. Clinical trial information: NCT01278810.