Investigation of the HDAC inhibitor resminostat in patients with sorafenib-resistant hepatocellular carcinoma (HCC): Clinical data from the phase I/II SHELTER study.
262 Background: Resminostat (4SC-201), an oral pan-HDAC inhibitor, is in clinical development in a variety of cancer indications. The SHELTER study aims to evaluate safety, tolerability and efficacy in HCC patients (pts) exhibiting progressive disease under sorafenib first-line therapy. Methods: Pts with advanced HCC, (BCLC B or C) are included in a multi-center, open-label, two-arm parallel group trial. Radiologic progression under sorafenib is determined acc. to RECIST by central review prior to study entry. For Arm A, dose escalation of resminostat and sorafenib is performed to determine the MTD. Resminostat is administered orally once-daily in a “5+9” schedule, consisting of 5 consecutive treatment days followed by a 9-day rest period resulting in 14 day cycles on dose levels of 200 (DL1), 400 (DL2) and 600 mg (DL3+4), either combined with continuously taken sorafenib at 400 (DL1-3) or 800 mg (DL4) (Arm A), or as resminostat monotherapy (600 mg, Arm B). Primary objective is to determine progression-free survival after 12 weeks (w) (6 cycles). Secondary objectives include safety, tolerability, tumor response, TTP, OS, PK, biomarkers. Results: To date, 39 pts were treated with 600 mg resminostat alone or on DL1-4 in combination with sorafenib. Up to now, no DLT occurred in 5 pts treated on DL4. Most frequently AE observed include CTC grade 1-2 gastrointestinal complaints such as nausea and vomiting and skin disorders like rash, pruritus and HFSR. CTC Grade 3-4 toxicity documented in SAE reports consisted mainly of no-hematological events and was mostly related to the tumor disease. Interim results revealed that 15 out of 27 pts (56%) assessed after 6 w of treatment, and 11 out of 24 pts after 12 w displayed SD. In one patient treated on DL2, SD persisted for more than 1 year along with good long-term tolerability. Conclusions: Preliminary clinical data show a favorable drug profile of resminostat either in mono or in combination treatment with sorafenib. No DLT was observed on the highest DL of the combination therapy up to now. Initial data on toxicity and therapeutic activity to overcome resistance to sorafenib are promising and will be updated for the meeting.