Yuki Makino

Regorafenib as Second-Line Systemic Therapy May Change the Treatment Strategy and Management Paradigm for Hepatocellular Carcinoma

At the European Society of Medical Oncology World Congress of Gastrointestinal Cancer held in Barcelona, Spain, on 30th June 2016, positive outcomes were reported by the Study of Regorafenib after Sorafenib in Patients with Hepatocellular Carcinoma (RESORCE) trial, which investigated the efficacy of regorafenib as second-line therapy after sorafenib failure [1]. In this clinical trial, the group who received regorafenib achieved a survival benefit of approximately 2.8 months compared to the placebo group. Overall survival (OS) was 10.6 months in the regorafenib arm compared with 7.8 months in the placebo arm, with a hazard ratio (HR) of 0.62 (95% confidence interval [CI]: 0.50–0.78; p<0.001). These are groundbreaking results. The positive outcome achieved by this second-line systemic therapy is a major development, especially after the numerous reports of failures in clinical studies of first-and second-line systemic therapeutic agents (table ​(table1).1). Regorafenib therapy is expected to significantly prolong life expectancy by approximately 2.8 months in patients with hepatocellular carcinoma (HCC) who develop progressive disease (PD) during sorafenib therapy. This development will certainly lead to drastic changes in the treatment strategy and management paradigm for HCC. Table 1 Phase III Clinical Trials of Japanese Participation for HCC Design of the RESORCE Trial The RESORCE trial enrolled 573 patients with advanced HCC corresponding to Barcelona Clinic Liver Cancer (BCLC) stage B or C who were unresponsive to sorafenib. The patients were divided into placebo and regorafenib arms at a 1:2 ratio for the daily administration of placebo and oral regorafenib (160 mg), respectively, for three weeks on and one week off (four weeks/cycle) (fig. ​(fig.1).1). Geographic region, performance status on the Eastern Cooperative Oncology Group scale, α-fetoprotein level (≥400 or <400 ng/mL), macrovascular invasion, and extrahepatic disease were used as allocation factors. This study excluded patients who were intolerant of sorafenib and who discontinued the treatment because of side effects. It enrolled only those patients who discontinued sorafenib because of evidence of PD on imaging studies. In addition, patients were included only if they had received ≥400 mg sorafenib for at least 20 of 28 days immediately prior to radiologically detected PD. In other words, this trial was designed (1) to ensure regorafenib tolerance among patients, and to reduce the occurrence of the drug-specific skin symptoms because the compound is structurally similar to sorafenib [2,3] (fig. ​(fig.2)2) and (2) to reduce the effect of post-trial treatment on OS in both the placebo and treatment arms by using a homogeneous group of patients who developed PD due to sorafenib failure. Fig. 1 Design of the RESORCE Trial. ECOG PS=Eastern Cooperative Oncology Group Performance Status; RECIST=Response Evaluation Criteria in Solid Tumors. Fig. 2 Chemical structure of Regorafenib is very similar to that of Sorafenib. In general, post-progression survival (PPS) is defined as the time interval between the diagnosis of PD after primary treatment and the patients death, and OS is the sum of PPS and progression-free survival (PFS). Therefore, even significant differences in PFS can be canceled out because PPS is prolonged. Indeed, OS showed a stronger correlation with PPS than with PFS in a clinical trial of sorafenib [4]. Because HCC responds extremely well to locoregional therapy, it is often used as post-trial treatment even in cases in which locoregional therapy is no longer applicable and molecular targeted agents are subsequently administered in accordance with the protocol, provided that the patients general condition is stable. This rarely happens with other types of cancer and is therefore essentially unique to HCC, owing to the availability of powerful locoregional therapies such as intra-arterial infusion chemotherapy [5, 6, 7], transcatheter arterial chemoembolization (TACE) [8, 9], and radiofrequency ablation [10, 11, 12]. These post-trial treatments are capable of canceling out any difference in the primary endpoint OS by prolonging PPS [13]. Indeed, previous clinical trials of second-line agents other than regorafenib have always included patients intolerant to sorafenib, which may have increased the influence of post-trial treatment and thus contributed to their negative outcomes. Patients unresponsive to sorafenib are those who develop PD during sorafenib therapy and are likely to have relatively poor hepatic function and overall general condition. By contrast, patients intolerant to sorafenib are those who discontinue the treatment because of side effects; these patients are in relatively stable conditions because of negligible amounts of internalized sorafenib, and a lack of HCC progression. Because of their clinical stability, patients intolerant to sorafenib are inevitably treated by locoregional therapy or various other post-trial treatments, including the re-administration of sorafenib, regardless of whether they received an actual second-line agent or placebo during the trial. With this in mind, clinical trials of second-line agents should enroll only patients who are unresponsive to sorafenib [14]. The RESORCE trial was the first clinical study to reflect this point in the trial design (fig. ​(fig.1).1). The benefit of excluding patients intolerant to sorafenib was demonstrated in the subanalysis of a previous phase II study of axitinib, which generated an excellent HR and a significant study outcome [15, 16]. The second noteworthy point in the design of the RESORCE trial is that the allocation factors of macrovascular invasion and extrahepatic disease were treated as independent stratification factors. In general, the designs of previous clinical trials of molecular targeted agents involved allocation factors specifying “vascular invasion and/or extrahepatic spread” or “neither.” However, because vascular invasion is an extremely poor prognostic factor for HCC, assigning vascular invasion to the same category as extrahepatic spread may have influenced the outcome of these clinical trials. For example, when the treatment group contains more patients with vascular invasion but the placebo group includes more patients with extrahepatic spread, such sampling bias will put the treatment group at a significant disadvantage. In fact, such allocation imbalance apparently contributed to a negative outcome in a clinical trial of brivanib as second-line therapy [17] (table ​(table22). Table 2 Imbalance between Brivanib and Placebo Arm in BRISK-PS Trial The design of the RESORCE trial is excellent because it reflects what was learned from the negative outcomes of past trials and the reasons for those outcomes.

Usefulness of the Multimodality Fusion Imaging for the Diagnosis and Treatment of Hepatocellular Carcinoma

A multimodality fusion imaging system has been introduced for the clinical practice of diagnosis and treatment of hepatocellular carcinoma (HCC), especially for loco-regional treatment. An ultrasonography (US) fusion imaging system can provide a side-by-side display of real-time US images and any cross-sectional images of multiplanar reconstruction of CT or MRI that synchronize real-time US. The US fusion imaging system enables us to perform radiofrequency ablation (RFA) for HCCs difficult to detect on conventional US safely. Besides, we can evaluate the treatment effects of RFA easily at the bedside by combining the contrast-enhanced US and the US fusion imaging system. Fusion images of pre- and post-RFA CT have been utilized for the assessment of the treatment effects of RFA. Although the treatment effects of RFA have been conventionally evaluated, comparing pre- and post-RFA CT side-by-side, the evaluation tends to be inaccurate. On CT fusion images, the tumor and the ablation zone are overlaid and we can grasp the positional relation easily, leading to quantitative and more accurate evaluation. The multimodality fusion imaging system has become quite an important tool for loco-regional treatment of HCC because of its usefulness for both the guidance during the RFA procedure and the evaluation of its treatment effects.

Ultrasonography fusion imaging system increases the chance of radiofrequency ablation for hepatocellular carcinoma with poor conspicuity on conventional ultrasonography.

Objectives: To investigate the usefulness of the ultrasonography (US) fusion imaging system for radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC). Methods: Since the US fusion imaging system became available in 2010, we have conducted RFA with this system in all cases. The characteristics of 75 patients with 120 HCCs and 89 patients with 123 HCCs who underwent RFA before the introduction of this system (period A) and after it (period B), respectively, were retrospectively compared. Results: Significant difference in the characteristics of the patients and HCCs between the two periods was found only in the proportion of HCCs with poor conspicuity on grayscale US treated with RFA (1.7%, 2/120 for period A vs. 15.4%, 19/123 for period B, p < 0.01). Among the 19 HCCs with poor conspicuity on grayscale US for period B, 5 and 9 HCCs were identified on grayscale US and contrast-enhanced US, respectively, by the use of the US fusion imaging system, whereas the 5 remaining undetectable HCCs were treated by using the system in conjunction with reference images displayed side-by-side with grayscale US. Conclusion: Since the introduction of the US fusion imaging system, it has become possible to perform RFA for HCCs with poor conspicuity on grayscale US.

Renal impairment during the treatment of telaprevir with peginterferon and ribavirin in patients with chronic hepatitis C

Renal damage has been reported as an important complication during combination treatment of peginterferon (PEG IFN), ribavirin (RBV) and telaprevir (TVR) for chronic hepatitis C. However, very little is known about this complication. We investigated the role TVR plays in renal damage during this triple therapy.

Utility of computed tomography fusion imaging for the evaluation of the ablative margin of radiofrequency ablation for hepatocellular carcinoma and the correlation to local tumor progression

To demonstrate the usefulness of the computed tomography (CT) fusion imaging for the evaluation of treatment effect of radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC).

Sonazoid-enhanced ultrasonography for the diagnosis of an intrapancreatic accessory spleen: A case report

We report a case of an intrapancreatic accessory spleen in 59‐year‐old man, in which contrast‐enhanced sonography (US) using Sonazoid, a second‐generation contrast agent, was useful for the diagnosis. Sonazoid‐enhanced US could prove both hypervascularity and the existence of reticuloendothelial cell systems in the mass, which is the key to the diagnosis of an accessory spleen. Sonazoid‐enhanced US might become a standard imaging technique for the diagnosis of an accessory spleen.

Usefulness of the Extracted-Overlay Function in CT/MR-Ultrasonography Fusion Imaging for Radiofrequency Ablation of Hepatocellular Carcinoma

Objectives: We developed a novel technique of the extracted-overlay function in CT/MR-ultrasonography (US) fusion imaging for radiofrequency ablation (RFA), in which only a tumor extracted from CT/MR images with a virtual ablative margin of arbitrary thickness is overlaid on US. The usefulness of this function is investigated in this preliminary report. Methods: The volume data of the extracted tumor with a virtual ablative margin were created on an image-processing workstation, and transported into a US unit equipped with a CT/MR-US fusion imaging system. After the positional registration of US and transported images, the extracted tumor with an ablative margin could be overlaid on US. In RFA, using this function, an electrode was inserted targeting the overlaid tumor with an ablative safety margin of 5 mm on US, and the treatment effect was evaluated by dynamic CT. Treatment results of 23 consecutive hepatocellular carcinomas (HCCs) that underwent RFA using this function were retrospectively analyzed. Results: Complete tumor ablation was achieved in 22 (95.7%) and 1 (4.3%) HCCs in 1 and 2 treatment sessions, respectively. Conclusions: Due to the visualization of an extracted tumor with an ablative safety margin on a US image, even during and after ablation, this function is useful for treatment planning and guidance of RFA.

Feasibility of Extracted-Overlay Fusion Imaging for Intraoperative Treatment Evaluation of Radiofrequency Ablation for Hepatocellular Carcinoma

Background and Aims: Extracted-overlay fusion imaging is a novel computed tomography/magnetic resonance-ultrasonography (CT/MR-US) imaging technique in which a target tumor with a virtual ablative margin is extracted from CT/MR volume data and synchronously overlaid on US images. We investigated the applicability of the technique to intraoperative evaluation of radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC). Methods: This retrospective study analyzed 85 HCCs treated with RFA using extracted-overlay fusion imaging for guidance and evaluation. To perform RFA, an electrode was inserted targeting the tumor and a virtual 5-mm ablative margin overlaid on the US image. Following ablation, contrast-enhanced US (CEUS) was performed to assess the ablative margin, and the minimal ablative margins were categorized into three groups: (I) margin <0 mm (protrusion), (II) margin 0 to <5 mm, and (III) margin ≥5 mm. Margin assessment was based on the positional relationship between the overlaid tumor plus margin and the perfusion defect of the ablation zone. Tumors in group I underwent repeat ablation until they were in groups II or III. The final classifications were compared with those obtained by retrospectively created fusion images of pre- and post-RFA CT or MR imaging (CT-CT/MR-MR fusion imaging). Results: Treatment evaluation was impossible using CEUS in six HCCs because the tumors were located far below the body surface. Of the remaining 79 HCCs, the categorizations of minimal ablative margins between CEUS extracted-overlay fusion imaging and CT-CT/MR-MR fusion imaging were in agreement for 72 tumors (91.1%) (Cohens quadratic-weighted kappa coefficient 0.66, good agreement, p<0.01). Conclusions: Extracted-overlay fusion imaging combined with CEUS is feasible for the evaluation of RFA and enables intraoperative treatment evaluation without the need to perform contrast-enhanced CT.

Sodium taurocholate cotransporting polypeptide inhibition efficiently blocks hepatitis B virus spread in mice with a humanized liver

Sodium taurocholate cotransporting polypeptide (NTCP) is a recently discovered hepatitis B virus (HBV) receptor. In the present study, we used TK-NOG mice with a humanized liver to examine the impact of endogenous NTCP expression on HBV infection. Upon inoculation with HBV, these mice exhibited clear viremia in 2 weeks, and serum HBV DNA levels gradually increased. The frequency of HBsAg-positive hepatocytes in the liver was 5.1 ± 0.6% at 2 weeks and increased with increasing HBV DNA levels, reaching 92.9 ± 2.8% at 10 to 12 weeks. In vivo siRNA-mediated NTCP knockdown before and after HBV inoculation significantly suppressed the levels of HBV replication and the frequency of HBsAg-positive hepatocytes at 2 weeks, whereas NTCP knockdown 13 weeks after infection did not affect these parameters. Similar to the humanized mouse livers in the early phase of HBV infection, human liver samples from chronic hepatitis B patients, especially those treated with nucleos(t)ide analogues, contained a considerable number of hepatocytes that were negative for the anti-HBs antibody. In conclusion, NTCP inhibition prevents the spread of HBV-infected hepatocytes in mice with a humanized liver. NTCP-targeted therapy has potential for regulating HBV infection in patients with chronic hepatitis B.

Solitary Fibrous Tumor of the Liver from Development to Resection

A 55-year-old man was annually followed up for a large hepatic cyst. In 2006, a 20-mm nodule was detected in contact with the cyst that gradually grew thereafter. By 2013, the mass had expanded to 90 mm, and a percutaneous biopsy revealed a solitary fibrous tumor (SFT). Surgical resection was subsequently performed, and the patient has since been doing well for 11 months, without recurrence. SFT of the liver is a rare neoplasm; only 44 cases have been reported to date. This is the first report to describe the long-term progression of hepatic SFT from the time of its development.