Kaseb, Ahmed O

Abstract Hepatocellular carcinoma (HCC) mortality is increasing globally, partly due to the growing prevalence of nonviral liver diseases. Genome‐wide association studies (GWAS) have identified genetic variants associated with HCC development. Leveraging GWAS summary statistics and linkage disequilibrium score regression (LDSR), we investigated disease co‐development with hepatitis C virus‐negative (HCV‐negative) HCC to provide unique insights into HCC etiology and prioritize relationships for further causal inquiry. We utilized the LDSR statistical framework to estimate the genetic correlation and heritability between HCV‐negative HCC with 901 epidemiologic, behavioral, and clinical traits from the United Kingdom Biobank (UKBB). First, we set the threshold for observed scale heritability of each trait at 0.02 to ensure reliable inferences with adequate study power. Next, we observed significant positive genetic correlations between HCV‐negative HCC and blood‐based biomarkers of liver injury (ALT, GGT) and allostatic load (including glycated hemoglobin, blood pressure, and total albumin). We also identified a positive genetic correlation between HCV‐negative HCC and diseases associated with metabolic dysfunction‐associated steatotic liver disease (MASLD), including diabetes, hypertension, chronic ischemic heart disease, and others. Taken together, our results help to identify polygenic and pleiotropic signals related to different phenotypic traits associated with HCC and support further exploration of the predictive power of blood‐based biomarkers identified in this study for inferring HCC development among HCV‐negative individuals.

Background and Aims: Despite the substantial impact of environmental factors, individuals with a family history of liver cancer have an increased risk for HCC. However, genetic factors have not been studied systematically by genome-wide approaches in large numbers of individuals from European descent populations (EDP). Approach and Results: We conducted a 2-stage genome-wide association study (GWAS) on HCC not affected by HBV infections. A total of 1872 HCC cases and 2907 controls were included in the discovery stage, and 1200 HCC cases and 1832 controls in the validation. We analyzed the discovery and validation samples separately and then conducted a meta-analysis. All analyses were conducted in the presence and absence of HCV. The liability-scale heritability was 24.4% for overall HCC. Five regions with significant ORs (95% CI) were identified for nonviral HCC: 3p22.1, MOBP, rs9842969, (0.51, [0.40–0.65]); 5p15.33, TERT, rs2242652, (0.70, (0.62–0.79]); 19q13.11, TM6SF2, rs58542926, (1.49, [1.29–1.72]); 19p13.11 MAU2, rs58489806, (1.53, (1.33–1.75]); and 22q13.31, PNPLA3, rs738409, (1.66, [1.51–1.83]). One region was identified for HCV-induced HCC: 6p21.31, human leukocyte antigen DQ beta 1, rs9275224, (0.79, [0.74–0.84]). A combination of homozygous variants of PNPLA3 and TERT showing a 6.5-fold higher risk for nonviral-related HCC compared to individuals lacking these genotypes. This observation suggests that gene-gene interactions may identify individuals at elevated risk for developing HCC. Conclusions: Our GWAS highlights novel genetic susceptibility of nonviral HCC among European descent populations from North America with substantial heritability. Selected genetic influences were observed for HCV-positive HCC. Our findings indicate the importance of genetic susceptibility to HCC development.

507 Background: Navitoclax (ABT-263) is an oral Bcl-2 homology-3 mimetic that binds with high affinity to pro-survival Bcl-2 proteins, resulting in apoptosis. Sorafenib, an oral multi kinase inhibitor inhibits tumor angiogenesis and also promotes apoptosis. The efficacy of either agent alone is limited; however, preclinical studies demonstrate synergy with the combination of navitoclax and sorafenib. Methods: In this phase 1 pharmacokinetic and pharmacodynamic study (NCT01364051), we evaluated the combination of navitoclax and sorafenib in a dose escalation cohort of patients with refractory solid tumors, with an expansion cohort in hepatocellular carcinoma (HCC). The study agents were provided by the Cancer Therapy Evaluation Program at National Cancer Institute under CRADA. Navitoclax and sorafenib were administered continuously on days 1 through 21 of 21-day cycles. The maximum tolerated dose (MTD) was determined using the continual reassessment method. Results: Ten patients were enrolled in the dose escalation cohort and 15 patients with HCC were enrolled in the expansion cohort. Two dose levels were tested, dose level 1 (navitoclax 150 mg daily plus sorafenib 400 mg twice daily) and dose level 2 (navitoclax 200 mg daily plus sorafenib 400 mg twice daily). At dose level 1, one dose limiting toxicity (DLT) [grade 3 aspartate aminotransferase elevation] was observed among 6 patients treated at this dose level. In a cohort of 3 patients treated at dose level 2, two DLTs were observed (grade 3 hypertension, and grade 3 rash), hence dose level 1 was identified as the MTD. Among all patients, the most common grade 3 toxicity was thrombocytopenia (5 patients, 20%): there were no grade 4 or 5 toxicities (Table). Patients received a median of 2 cycles (range 1-36 cycles) and all patients were off study treatment at data cut off. Six patients in the expansion cohort had stable disease, 5 had progressive disease and 4 with unavailable data. There were no partial or complete responses. Drug-drug interaction between navitoclax and sorafenib was not observed. The combination of navitoclax and sorafenib did not increase induction of apoptosis compared with navitoclax alone. Conclusions: Navitoclax plus sorafenib resulted in manageable, but not ideal toxicities for continuous oral administration which precluded dose escalation. The lack of clinical benefit in the HCC expansion cohort does not support further development of this combination for the treatment of advanced HCC. Clinical trial information: NCT01364051 . [Table: see text]

Abstract Background and Aims Although many studies revealed transcriptomic subtypes of HCC, concordance of the subtypes are not fully examined. We aim to examine a consensus of transcriptomic subtypes and correlate them with clinical outcomes. Approach and Results By integrating 16 previously established genomic signatures for HCC subtypes, we identified five clinically and molecularly distinct consensus subtypes. STM (STeM) is characterized by high stem cell features, vascular invasion, and poor prognosis. CIN (Chromosomal INstability) has moderate stem cell features, but high genomic instability and low immune activity. IMH (IMmune High) is characterized by high immune activity. BCM (Beta‐Catenin with high Male predominance) is characterized by prominent β‐catenin activation, low miRNA expression, hypomethylation, and high sensitivity to sorafenib. DLP (Differentiated and Low Proliferation) is differentiated with high hepatocyte nuclear factor 4A activity. We also developed and validated a robust predictor of consensus subtype with 100 genes and demonstrated that five subtypes were well conserved in patient‐derived xenograft models and cell lines. By analyzing serum proteomic data from the same patients, we further identified potential serum biomarkers that can stratify patients into subtypes. Conclusions Five HCC subtypes are correlated with genomic phenotypes and clinical outcomes and highly conserved in preclinical models, providing a framework for selecting the most appropriate models for preclinical studies.

480 Background: Currently, there is a lack of imaging biomarkers of immunotherapy outcome in hepatocellular carcinoma (HCC). The study aim was to determine if HCC enhancement on MRI and stiffness change measured by magnetic resonance elastography (MRE) can predict immunotherapy response. Methods: This was a prospective, Institutional Review Board approved study of 38 patients with HCC treated with immune checkpoint blockade (ICB) therapy. All patients had liver MRI/MRE and HCC biopsy at baseline, and MRI/MRE with biopsy or resection after 6 weeks therapy. HCC stiffness (kPa) was measured on MRE elastograms (liver stiffness maps). HCC enhancement and change in stiffness were compared with treatment response to ICB in 1) non-surgical patients (pembrolizumab), and 2) surgical patients (nivolumab +/- ipilimumab). For non-surgical patients, treatment response was defined as overall survival >1 year. For surgical patients, treatment response was defined as <50% viable tumor at time of resection. Analysis was performed using descriptive statistics and Spearman correlation; p-value <0.05 was considered statistically significant. Results: Twenty-five patients were evaluable. Median age was 67 years (32, 78). Etiology of liver disease was NASH (n=8), HCV (n=8), HBV (n=2) and unknown (n=7). Treatment response occurred in 11/25 (44%) patients. Median HCC size and change in size were 4.7 cm (1.2, 14.0) and –0.32 cm, respectively. Median baseline HCC stiffness and change in stiffness were 5 kPa (2.2, 12.4) and –0.1 kPa (–2.2, 1.5), respectively. Median change in HCC size for responders and non-responders was –1.2 cm (–4.8, 0.4) and 0 cm (–1.5, 1.1), respectively (p = 0.02). Treatment response was associated with absence of portal venous phase capsular enhancement and increase in HCC stiffness, (p<0.001). Conclusions: Capsular enhancement and MRE stiffness change may be useful biomarkers of immune cell activated response to ICB therapy.

268 Background: TRC105, an endoglin antibody, potentiates the activity of sorafenib (S) in preclinical HCC models, and TRC105 + S demonstrated a 33% partial response rate (5/15 pts) by RECIST, at RP2D doses of TRC105 in HCC pts ( Clin Can Res 2017). Adverse events characteristic of each drug were not increased in frequency or severity when the two drugs were administered concurrently. Methods: P1: Compare wkly TRC105 dosing vs four wkly doses followed by every other wkly dosing + S 800 mg daily. P2: Four objective responses are required in 21 pts to reject the null hypothesis that the true response rate probability is < 5% with an alpha level of 0.1 and 80% power. Key inclusion criteria: disease not amendable to surgical or local therapies, ECOG ≤ 1; Child-Pugh A or B (7 points) classification. Results: Thirteen pts were enrolled in phase 1b at TRC105 10 mg/kg wkly for four doses and 15 mg/kg every other week thereafter + S. Mean serum levels of TRC105 exceeded the target conc. following 4 wkly doses of TRC105 at 10 mg/kg (mean = 34 µg/ml, range BLOQ-80). Mean trough conc. decreased following every other week dosing (mean = 13 µg/ml, range BLOQ-31), resulting in infusion reactions or a continued requirement for premedication. Therefore, wkly dosing of TRC105 at 10 mg/kg is the recommended Phase 2 dose. ADA were detected in 10 of 14 pts and correlated with lower than expected PK conc. Common TRC105 related AEs included ≤ G2 epistaxis, ≤ G2 fatigue and ≤ G2 headache. Common S related AEs included ≤ G3 fatigue, ≤ G3 hand foot syndrome and ≤G2 epistaxis. A total of 3 out of 14 evaluable patients (21%) enrolled in phase 1 and 2 achieved durable PR, 2 of these ongoing at week 45 and 17. Conclusions: TRC105 dosed at 10 mg/kg wkly was required to achieve target conc. due to higher clearance in HCC pts, which may have been influenced by a higher rate of ADA compared to studies of TRC105 in other tumor types. The combination of TRC105 + S demonstrated encouraging signs of activity, including durable PR in 2/9 evaluable pts in Phase 1b and 1/5 pts thus far in Phase 2. An additional 16 pts will be enrolled at the RP2D to assess the primary endpoint of ORR by RECIST. Clinical trial information: NCT01806064.

350 Background: BTCs are often diagnosed at an advanced stage and have a poor prognosis. The standard therapy for aBTCs is the combination of GC. However, the median overall survival (mOS) is dismal at 11.7 months (mos) with a median progression free survival (mPFS) of 8 mos. Methods: A single arm, phase II study was conducted at MD Anderson and Mayo Clinic Arizona. Patients (pts) with aBTC were treated at initial dose level of G/C/N (in mg/m2) at 1000/25/125 (n = 30) which was reduced to lower doses due to grade 3/4 hematological (heme) toxicity (tox) - G/C/N: 800/25/100 (n = 30). Cycles were q21 days with restaging q3 cycles until progression. PFS was the primary endpoint (endpt). Using a Bayesian hypothesis test-based design, we assumed mPFS of 8 mos under the null hypothesis (H0), 10 mos under the alternative (H1). Secondary endpts included mOS, RECIST v1.1 response rate (RR), safety and CA19-9 response. Results: 60 pts were enrolled with 51 being response-evaluable having received more than 1 cycle of therapy (age: median 60 yrs [range 31-77], ECOG PS 0/1 (22/38), M/F (33/27), intrahepatic cholangiocarcinoma/extrahepatic/gallbladder (38/9/13). Median follow-up was 14 mos and median number of treatment (trmt) cycles = 5.24. Pts at initial dose level had significant grade 3/4 heme tox: neutropenia, febrile neutropenia, anemia, and thrombocytopenia leading to trmt discontinuation in 6/30 pts. After dose reduction to G/C/N (in mg/m2) at 800/25/100, trmt was better tolerated with only 3 pts experiencing grade 4 heme tox. Non-heme tox were grade 3 in 19 pts: nausea/vomiting, diarrhea, thromboembolic event/CVA, hypokalemia, constipation, cystitis, LFT elevations. The mPFS = 11.4 mos (95% CI: 6.1, 16.1) and mOS = 19.2 (95%CI: 13.6, NA), 1-year survival rate 67.6%. 51 pts evaluable for response: disease control rate (PR+CR+SD)-84.3% and RR-39%. 12 unresectable cases were operated post trmt with 1 pathologic CR. Conclusions: The combination of GCN was well tolerated at adjusted doses and demonstrates encouraging efficacy having met its mPFS endpt and an impressive mOS higher than historical control. These results merit evaluating GC +/-N in a randomized controlled study. Clinical trial information: NCT02392637.

301 Background: Endoglin plays a critical role in angiogenesis and is implicated in resistance to VEGF inhibition. TRC105, an endoglin antibody potentiates anti-tumor activity of sorafenib (S) in preclinical HCC models. The combination of TRC105 and S demonstrated encouraging evidence of activity, including a 33% partial response rate (5/15 pts) by RECIST, at RP2D doses of TRC105 in HCC ( Clin Can Res 2017). Adverse events characteristic of each drug were not increased in frequency or severity when the two drugs were administered concurrently, and most commonly included epistaxis, fatigue, headache and anemia. Methods: Following dose escalation, 21 pts will be enrolled at the RP2D. Four objective responses are required to reject the null hypothesis that the true response rate probability is < 5% with an alpha level of 0.1 and 80% power. Secondary endpoints: DR, PFS, frequency and severity of AEs, PK, immunogenicity, angiogenic biomarkers. Key inclusion criteria: disease not amendable to surgical or local therapies, ECOG ≤ 1; Child-Pugh A or B (7 points) classification. Results: Four pts have been enrolled in phase 1b at TRC105 10 mg/kg (n=4) weekly for four doses and 15 mg/kg every other week thereafter + S 800 mg daily without DLT. One of 3 evaluable pts achieved PR (41% reduction), ongoing at month 4. Serum levels of TRC105 exceeded the target concentration following 4 weekly doses of TRC105 at 10 mg/kg (mean = 59 µg/ml, range 43-80). Mean trough concentration decreased following every other week dosing (mean = 21 µg/ml, range 17-31). Common TRC105 related AEs included ≤ G2 epistaxis and G1 headache. Common S related AEs included G3 hand foot syndrome, ≤G3 periodontal disease, G2 hypertension, ≤G2 increased lipase, ≤G2 fatigue and G1 epistaxis. Conclusions: TRC105 dosed by a hybrid schedule of 10 mg/kg weekly for four doses followed by every other week dosing at 15 mg/kg was tolerable and did not potentiate the toxicity of S. The combination of TRC105 + S demonstrated additional signs of activity, including a PR in 1/3 evaluable pts. 21 pts will be enrolled at the RP2D to assess the primary endpoint of ORR by RECIST. Clinical trial information: NCT01806064.