Activity of cabozantinib (XL184) in hepatocellular carcinoma: Results from a phase II randomized discontinuation trial (RDT).

Abstract

4007 Background: Cabozantinib (cabo) is an oral, potent inhibitor of MET and VEGFR2. MET over-expression has been observed in advanced hepatocellular carcinoma (HCC). Anti-VEGF pathway agents have shown clinical benefit in pts w/ HCC. Simultaneous targeting of the MET and VEGF signaling pathways with cabo may therefore be a promising treatment strategy. Methods: Eligible HCC patients (pts) were required to have measurable disease per RECIST, ≤ 1 prior systemic regimen and Child-Pugh score of A. Pts received cabo at 100 mg qd over a 12 wk Lead-in stage. Tumor response (mRECIST) was assessed q6 wks. Treatment ≥ wk 12 was based on response: pts with PR continued open-label cabo, pts with SD were randomized to cabo vs placebo, and pts with PD discontinued. Primary endpoint in the randomized phase was progression free survival (PFS). The primary endpoint was overall response rate (RR) per mRECIST in the Lead-in stage. Results: Enrollment has been completed (n = 41); all pts are unblinded. Median age: 61 years (33 to 83). Males: 76%; Asian: 37%. HCC etiology: Hep B 24%; Hep C 22%; alcohol abuse 20%; other 38%. Extra-hepatic spread observed in 70%. Median number of prior systemic treatments was 1; prior sorafenib was 51%. Median baseline AFP was 368 ng/mL (3 – 259,298); 86% had elevated AFP at baseline. Median follow-up was 5.5 mos (0.8 -18.5). 29 pts (71%) completed the Lead-in stage. Median PFS from Study Day 1 was 4.2 mos. 2/36 pts evaluable for tumor assessment at 12 weeks achieved a confirmed PR (cPR) by original RECIST (RR 5%). One more pt randomized at Week 12 achieved a cPR at 18 weeks. 28/36 pts (78%) with ≥1 post-baseline scan had tumor regression (with no apparent relationship to prior sorafenib therapy). The overall disease control rate (DCR = PR+SD) at Week 12: was 68% (Asian subgroup: 73%). AFP responses (defined as reduction from baseline of >50% in pts with elevated AFP at baseline) in 26 pts with ≥1 post-baseline result: 10/26 (38%). Most common Gr 3/4 AEs: diarrhea (17%), palmar-plantar erythrodyesthesia (15%), and thrombocytopenia (10%). Conclusions: Cabo treatment exhibits activity in HCC pts regardless of prior sorafenib treatment. The safety profile was comparable to that of other VEGFR TKIs.