Inhibition of RhoGEF/RhoA alleviates regorafenib resistance and cancer stemness via Hippo signaling pathway in hepatocellular carcinoma.

Patients with hepatocellular carcinoma (HCC) are vulnerable to drug resistance. Although drug resistance has been taken much attention to HCC therapy, little is known of regorafenib and regorafenib resistance (RR). This study aimed to determine the drug resistance pattern and the role of RhoA in RR. Two regorafenib-resistant cell lines were constructed based on Huh7 and Hep3B cell lines. In vitro and in vivo assays were conducted to study RhoA expression, the activity of Hippo signaling pathway and cancer stem cell (CSC) traits. The data showed that RhoA was highly expressed, Hippo signaling was hypoactivated and CSC traits were more prominent in RR cells. Inhibiting RhoA could reverse RR, and the alliance of RhoA inhibition and regorafenib synergistically attenuated CSC phenotype. Furthermore, inhibiting LARG/RhoA increased Kibra/NF2 complex formation, prevented YAP from shuttling into the nucleus and repressed CD44 mRNA expression. Clinically, the high expression of RhoA correlated with poor prognosis. LARG, RhoA, YAP1 and CD44 show positive correlation with each other. Thus, inhibition of RhoGEF/RhoA has the potential to reverse RR and repress CSC phenotype in HCC.

Allosteric SHP2 inhibition enhances regorafenib's effectiveness in colorectal cancer treatment.

Colorectal cancer (CRC) is the third most common cancer globally. Regorafenib, a multi-target kinase inhibitor, has been approved for treating metastatic colorectal cancer patients who have undergone at least two prior standard anti-cancer therapies. However, regorafenib efficacy as a single agent remains suboptimal. A promising target at the crossroads of multiple signaling pathways is the Src homology 2 domain-containing protein tyrosine phosphatase (SHP2). However, a combination approach using SHP2 inhibitors (SHP099) and anti-angiogenic drugs (Regorafenib) has not been reported in current research. In this study, we conducted in vitro experiments combining SHP099 and regorafenib and established an MC-38 colon cancer allograft mouse model. Our results revealed that co-treatment with SHP099 and regorafenib significantly inhibited cell viability and altered the biological characteristics of tumor cells compared with treatment alone in vitro. Furthermore, the combination strategy demonstrated superior therapeutic efficacy compared to monotherapy with either drug. This was evidenced by reduced tumor size, decreased proliferation, increased apoptosis, normalized tumor microvasculature, and improved antitumor immune response in vivo. These findings suggest that the combination of an SHP2 inhibitor and regorafenib is a promising therapeutic approach for patients with colorectal cancer.

Regorafenib and glioblastoma: a literature review of preclinical studies, molecular mechanisms and clinical effectiveness.

Glioblastoma IDH wild type (GBM) is a very aggressive brain tumour, characterised by an infiltrative growth pattern and by a prominent neoangiogenesis. Its prognosis is unfortunately dismal, and the median overall survival of GBM patients is short (15 months). Clinical management is based on bulk tumour removal and standard chemoradiation with the alkylating drug temozolomide, but the tumour invariably recurs leading to patient's death. Clinical options for GBM patients remained unaltered for almost two decades until the encouraging results obtained by the phase II REGOMA trial allowed the introduction of the multikinase inhibitor regorafenib as a preferred regimen in relapsed GBM treatment by the National Comprehensive Cancer Network (NCCN) 2020 Guideline. Regorafenib, a sorafenib derivative, targets kinases associated with angiogenesis (VEGFR 1-3), as well as oncogenesis (c-KIT, RET, FGFR) and stromal kinases (FGFR, PDGFR-b). It was already approved for metastatic colorectal cancers and hepatocellular carcinomas. The aim of the present review is to focus on both the molecular and clinical knowledge collected in these first three years of regorafenib use in GBM.

The cumulative antitumor effects of regorafenib and radiotherapy in hepatocellular carcinoma.

Regorafenib is a second-line standard treatment for hepatocellular carcinoma (HCC). However, the efficacy of regorafenib is often limited due to drug resistance, individual differences among patients, and irrational drug use. Radiotherapy (RT) is an important method of localized HCC treatment, and combining RT with other therapies may exert a synergetic antitumor effect. Platelet-derived growth factor receptor-like (PDGFRL) is a tumor suppressor in various solid tumors. However, the function of PDGFRL in HCC is still unknown. In this study, we explored whether regorafenib and RT exert a synergetic effect on the treatment of HCC. The antitumor effect and mechanisms of the combination of regorafenib and RT were verified in a xenograft mouse model in vivo and in HCC cells in vitro. The combination treatment significantly inhibited cell proliferation and promoted apoptosis both in vitro and in vivo. PDGFRL, a potential target of regorafenib, was increased after cumulative treatment in HCC cells, and PDGFRL suppressed HCC cell proliferation and promoted apoptosis by inhibiting STAT3 pathway activation. Furthermore, the cumulative antitumor effect was dependent on the upregulated expression of PDGFRL and inhibition of STAT3 signaling pathway activation in HCC cells. This study increased the understanding of the molecular mechanism underlying the effect of regorafenib plus RT on HCC and provided a theoretical basis for the clinical practice of HCC.

Association between albumin-bilirubin grade and plasma trough concentrations of regorafenib and its metabolites M-2 and M-5 at steady-state in Japanese patients.

The aim of the present study was to determine whether the trough plasma concentrations (C0) of regorafenib and its metabolites, the N-oxide metabolite (M-2) and the desmethyl N-oxide metabolite (M-5), in 21 patients receiving regorafenib therapy were affected by albumin-bilirubin (ALBI) grade. Regorafenib was administered at dosages ranging from 40 to 160 mg once daily on a 3-week-on, 1-week-off cycle. C0 values of regorafenib and its major metabolites were measured by high-performance liquid chromatography on day 8 after treatment initiation. The C0 values of regorafenib and metabolites M-2 and M-5 were significantly lower in patients with ALBI grade 2 as compared with grade 1 (P = 0.023, 0.003 and 0.017, respectively). The total C0 of regorafenib and its metabolites was significantly higher in ALBI grade 1 patients relative to grade 2 (3.489 µg/mL vs. 1.48 µg/mL; P = 0.009). The median relative dose intensity (RDI) of patients categorized as ALBI grade 2 was significantly lower than that of grade 1 patients (21.9% vs. 62.9%; P = 0.006). In 15 colorectal cancer patients among the total 21 patients, patients with ALBI grade 2 (n = 9) had a significantly shorter median overall survival time than patients with grade 1 (n = 6; P = 0.013). Administering a low dose of regorafenib to patients with ALBI grade 2 reduces the RDI of regorafenib and lowers treatment efficacy, as an appropriate C0 of regorafenib is not maintained. Monitoring the C0 of regorafenib regularly is necessary to guide dose adjustment.

Regorafenib monotherapy or combined with an immune-checkpoint inhibitor as later-line treatment for metastatic colorectal cancer: a multicenter, real-world retrospective study in China.

OBJECTIVE: To evaluate the efficacy and safety of regorafenib monotherapy or in combination with immune-checkpoint inhibitor while treating Chinese patients with metastatic colorectal cancer (mCRC): a real-world study. METHODS: The data of patients with metastatic colorectal cancer who received regorafenib-containing regimen as the third or later line treatment at ten Chinese hospitals from Aug 2017 to Jun 2020 were retrospectively analyzed, including dosing details, survival data as well as adverse events. Survival analysis was further performed for patients administrated with regorafenib monotherapy and combined with an immune-checkpoint inhibitor based on Kaplan-Meier and Cox regression methods. The primary endpoint was overall survival. RESULTS: A total of 537 patients were included with a median age of 61, among whom 376 received regorafenib monotherapy and 245 received regorafenib combined with immune-checkpoint inhibitors. The clinicopathological characteristics of the two groups at baseline were mainly balanced. No significant difference in progression-free survival (PFS) was observed in patients receiving regorafenib monotherapy or combination therapy (3.8 vs. 5.5 months, p = 0.170). In contrast, patients receiving combination therapy had a more prolonged overall survival (OS) than those receiving regorafenib monotherapy (13.5 vs. 10.0 months, p = 0.001). The treatment regimen and regorafenib dosage were significant prognostic factors in the multivariate analysis. Significant benefits in PFS and OS were achieved in KRAS mutant and anti-angiogenesis treatment-naïve subgroups receiving combination therapy compared to monotherapy. No apparent increase was recorded in treatment-related adverse events in patients receiving combination therapy. CONCLUSION: Regorafenib plus an immune-checkpoint inhibitor has already been a widely adopted strategy in the later-line treatment for mCRC in the real world. The combination therapy yielded a significantly prolonged overall survival than regorafenib alone, with a manageable safety profile in Chinese patients, and warrants further investigation. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04835324. Registered 6th April 2021.

Comparing the efficacy of regorafenib and 5-fluorouracil-based rechallenge chemotherapy in the third-line treatment of metastatic colorectal cancer.

BACKGROUND: The optimal treatment for metastatic colorectal cancer (mCRC) after the second line is still controversial. Regorafenib has been the standard of care in this setting as it improved overall survival (OS) compared to placebo. In real-world practice chemotherapy rechallenge is also a preferred option even though supporting evidence is not enough. We aim to compare the efficacy of regorafenib and 5-fluorouracil-based (5-FU) rechallenge treatment in the third line setting of mCRC. METHODS: In this retrospective multi-institutional trial, mCRC patients from 21 oncology centers who progressed after 2 lines of chemotherapy were analyzed. Patients who were treated with regorafenib or rechallenge therapy in the third-line setting were eligible. Rechallenge chemotherapy was identified as the re-use of the 5-FU based regimen which was administered in one of the previous treatment lines. OS, disease control rate (DCR), progression free survival (PFS) and toxicity were analyzed. RESULTS: Three hundred ninety-four mCRC patients were included in the study. 128 (32.5%) were in the rechallenge, and 266 (67.5%) were in the regorafenib group. Median PFS was 5.82 months in rechallenge and 4 months in regorafenib arms (hazard ratio:1.45,95% CI, p = 0.167). DCR was higher in the rechallenge group than regorafenib (77% vs 49.5%, respectively, p = < 0.001). Median OS after the third-line treatment was 11.99 (95% CI, 9.49-14.49) and 8.08 months (95% CI, 6.88-9.29) for rechallenge and regorafenib groups, respectively (hazard ratio:1.51, 95% CI, p < 0.001). More adverse effects and discontinuation were seen with regorafenib treatment. CONCLUSION: Our study revealed that higher disease control and OS rates were achieved with rechallenge treatment compared to regorafenib, especially in patients who achieved disease control in one of the first two lines of therapy.

CHOP regulated by METTL14-m6A affects cell cycle arrest and regorafenib sensitivity in HCC cells.

BACKGROUND: Regorafenib, a multi-targeted kinase inhibitor, has been used in the treatment of Hepatocellular carcinoma (HCC). The purpose of this study is to investigate the mechanism of Regorafenib in HCC. METHODS: Regorafenib's impact on the sensitivity of HCC cells was assessed using CCK8. Differential gene expression analysis was performed by conducting mRNA sequencing after treatment with Regorafenib. The m6A methylation status of CHOP and differential expression of m6A methylation-related proteins were assessed by RIP and Western Blot. To explore the molecular mechanisms involved in the therapeutic effects of Regorafenib in HCC and the impact of METTL14 and CHOP on Regorafenib treatment, we employed shRNA/overexpression approaches to transfect METTL14 and CHOP genes, as well as conducted in vivo experiments. RESULTS: Treatment with Regorafenib led to a notable decrease in viability and proliferation of SK-Hep-1 and HCC-LM3 cells. The expression level of CHOP was upregulated after Regorafenib intervention, and CHOP underwent m6A methylation. Among the m6A methylation-related proteins, METTL14 exhibited the most significant downregulation. Mechanistic studies revealed that Regorafenib regulated the cell cycle arrest in HCC through METTL14-mediated modulation of CHOP, and the METTL14/CHOP axis affected the sensitivity of HCC to Regorafenib. In vivo, CHOP enhanced the anticancer effect of Regorafenib. CONCLUSION: The inhibition of HCC development by Regorafenib is attributed to its modulation of m6A expression of CHOP, mediated by METTL14, and the METTL14/CHOP axis enhances the sensitivity of HCC to Regorafenib. These findings provide insights into the treatment of HCC and the issue of drug resistance to Regorafenib.

Real-world dosing of regorafenib and outcomes among patients with metastatic colorectal cancer: a retrospective analysis using US claims data.

BACKGROUND: The randomized, dose-optimization, open-label ReDOS study in US patients with metastatic colorectal cancer (CRC) showed that, compared with a standard dosing approach, initiating regorafenib at 80 mg/day and escalating to 160 mg/day depending on tolerability increased the proportion of patients reaching their third treatment cycle and reduced the incidence of adverse events without compromising efficacy. Subsequently, the ReDOS dose-escalation strategy was included as an alternative regorafenib dosing option in the National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines. A retrospective analysis was conducted using a US claims database to assess whether inclusion of this dose-escalation strategy in NCCN Guidelines has influenced the use of flexible dosing in routine US clinical practice, and to describe clinical outcomes pre- and post-inclusion in NCCN Guidelines. METHODS: Patients with CRC in the Optum's de-identified Clinformatics® Data Mart database initiating regorafenib for the first time between January 2016 and June 2020 were stratified based on whether they initiated regorafenib pre- or post-inclusion of ReDOS in NCCN Guidelines, and in two groups: flexible dosing (< 160 mg/day; < 84 tablets in the first treatment cycle) and standard dosing (160 mg/day; ≥ 84 tablets in the first treatment cycle). The primary endpoints were the proportion of patients who initiated their third treatment cycle and the mean number of treatment cycles per group. RESULTS: 703 patients initiated regorafenib during the study period, of whom 310 (44%) initiated before and 393 (56%) initiated after inclusion of ReDOS in NCCN Guidelines. After inclusion in the guidelines, the proportion of patients who received flexible dosing increased from 21% (n = 66/310) to 45% (n = 178/393), the proportion who received standard dosing decreased from 79% (n = 244/310) to 55% (n = 215/393), the proportion who initiated their third treatment cycle increased from 36% (n = 113/310) to 46% (n = 179/393), and the mean (standard deviation) number of treatment cycles increased from 2.6 (2.9) to 3.2 (3.1). CONCLUSIONS: Following inclusion of ReDOS in NCCN Guidelines, real-world data suggest that US clinicians have markedly increased use of flexible dosing in clinical practice, potentially maximizing clinical benefits and safety outcomes for patients with metastatic CRC receiving regorafenib.

The VEGFs/VEGFRs system in Alzheimer's and Parkinson's diseases: Pathophysiological roles and therapeutic implications.

The vascular endothelial growth factors (VEGFs) and their cognate receptors (VEGFRs), besides their well-known involvement in physiological angiogenesis/lymphangiogenesis and in diseases associated to pathological vessel formation, play multifaceted functions in the central nervous system (CNS). In addition to shaping brain development, by controlling cerebral vasculogenesis and regulating neurogenesis as well as astrocyte differentiation, the VEGFs/VEGFRs axis exerts essential functions in the adult brain both in physiological and pathological contexts. In this article, after describing the physiological VEGFs/VEGFRs functions in the CNS, we focus on the VEGFs/VEGFRs involvement in neurodegenerative diseases by reviewing the current literature on the rather complex VEGFs/VEGFRs contribution to the pathogenic mechanisms of Alzheimer's (AD) and Parkinson's (PD) diseases. Thereafter, based on the outcome of VEGFs/VEGFRs targeting in animal models of AD and PD, we discuss the factual relevance of pharmacological VEGFs/VEGFRs modulation as a novel and potential disease-modifying approach for these neurodegenerative pathologies. Specific VEGFRs targeting, aimed at selective VEGFR-1 inhibition, while preserving VEGFR-2 signal transduction, appears as a promising strategy to hit the molecular mechanisms underlying AD pathology. Moreover, therapeutic VEGFs-based approaches can be proposed for PD treatment, with the aim of fine-tuning their brain levels to amplify neurotrophic/neuroprotective effects while limiting an excessive impact on vascular permeability.

Efficacy and Safety of TACE Combined with Regorafenib versus TACE Combined with Camrelizumab in Hepatocellular Carcinoma With Untreatable Progression After TACE Combined with Sorafenib Therapy: A Case Control Study.

PURPOSE: To evaluate the efficacy and safety of transarterial chemoembolization (TACE) combined with regorafenib (hereafter, TACE-regorafenib) or camrelizumab (hereafter, TACE-camrelizumab) for treating hepatocellular carcinoma (HCC) with untreatable progression after TACE and sorafenib therapy. METHODS: The medical records of patients with HCC who received TACE-regorafenib or TACE-camrelizumab between September 2018 and December 2023 were retrospectively evaluated. Therapeutic response, overall survival (OS), progression-free survival (PFS), and adverse events (AEs) were compared between the two groups. RESULTS: A total of 76 patients were enrolled in this study, with 41 and 35 patients in the TACE-regorafenib and TACE-camrelizumab groups, respectively. The objective response rates in the TACE-regorafenib and TACE-camrelizumab groups were 9.8% and 8.6%, respectively, with no statistically significant difference between the two groups (P = 0.859). Similarly, there was no statistically significant difference in disease control rates between the two groups (61.0% vs 68.6%, P = 0.838). The median OS was 11 months in the TACE-regorafenib group and 10 months in the TACE-camrelizumab group, with no significant difference between the two groups (P = 0.348). The TACE-regorafenib group had a median PFS of 7 months, which was significantly longer than that of the TACE-camrelizumab group (4 months, P = 0.004). There was no significant difference in the incidence of AEs between the two groups (P = 0.544). CONCLUSIONS: TACE-regorafenib was safe, well-tolerated, and showed promising efficacy in patients with sorafenib-refractory advanced HCC, whereas TACE-camrelizumab demonstrated similar survival benefits.

Impact of post-progression survival in second-line treatment with molecular target agents for unresectable hepatocellular carcinoma.

AIM: Sequential therapies are essential to extend overall survival (OS) in patients with unresectable hepatocellular carcinoma (HCC). Several second-line treatments with molecular target agents have shown survival benefits. However, the significance of post-progression survival (PPS) in extending OS in patients with HCC given such treatments remains uncertain. METHODS: Through a systematic review of the literature in the PubMed database, this study investigated the correlation between PPS and OS and that between progression-free survival (PFS) and OS in patients with HCC given second-line treatments. RESULTS: In total, 3935 patients who had received second-line treatment with regorafenib, ramucirumab, or cabozantinib, which are approved molecular target agents, were identified. In the patients treated with regorafenib, PPS showed a strong correlation with OS (R2 = 0.729, R = 0.854, p < 0.001) whereas PFS showed a weak correlation (R2 = 0.218, R = 0.467, p = 0.021). In the patients treated with ramucirumab, PPS showed a strong correlation with OS (R2 = 0.800, R = 0.894, p = 0.016) whereas PFS showed a negligible correlation (R2 = 0.020, R = 0.140, p = 0.791). In the patients treated with cabozantinib, PPS showed a strong correlation with OS (R2 = 0.856, R = 0.925, p = 0.003) as did PFS (R2 = 0.946, R = 0.973, p < 0.001). CONCLUSIONS: PPS plays a more significant role than PFS in extending OS in patients given second-line treatment for unresectable HCC. Sequential therapies after disease progression in second-line treatment are essential to acquire good OS. Maintenance of hepatic reserve function and the patient's general condition is essential during systemic treatments for unresectable HCC.

Regorafenib in patients with metastatic colorectal cancer in Spain: from clinical trials to real-world evidence.

Aim: To describe the evolution of regorafenib use, since its approval, in patients with previously treated metastatic colorectal cancer (mCRC) in routine clinical practice in Spain. Methods: We extracted patient characteristics, dosing, safety and efficacy data for the Spanish cohorts of the CORRECT and CONSIGN trials, and the real-world CORRELATE study. Results: The Spanish cohorts represented 10.7-13.8% of the global cohorts. Efficacy and safety in the Spanish cohorts reflected findings from the global cohorts, with evidence of a flexible dosing approach being adopted in routine clinical practice. Conclusion: Regorafenib use in patients with mCRC has evolved in the real-world setting, emphasizing the need for further research evaluating dosing patterns that can optimize clinical outcomes in these patients.Clinical trial registration: The CORRECT trial is registered at ClinicalTrials.gov, number NCT01103323; the CONSIGN trial is registered at ClinicalTrials.gov, number NCT01538680; the CORRELATE study is registered at ClinicalTrials.gov, number NCT02042144.

Bowel cancer (also called colorectal cancer) affects the large bowel, including the colon and rectum. Approximately one in ten patients with advanced bowel cancer that has spread to other areas of the body (metastatic bowel cancer) survive 5 years after diagnosis or the start of treatment.Regorafenib is a treatment for patients with advanced bowel cancer that has continued to spread after receiving other treatments. It can slow down cancer growth, as shown in three international studies (CORRECT, CONSIGN and CORRELATE). In Spain, bowel cancer is the most common type of cancer and the cancer that causes the second most deaths. This study describes how the use of regorafenib in Spain has changed since it was approved in 2012, by looking at the patients from Spain who made up 11­14% of the participants in the three international studies.The CORRECT trial that compared regorafenib with a non-therapeutic placebo and the CONSIGN trial of regorafenib alone showed that treatment with regorafenib prolonged life and was well tolerated in patients with metastatic bowel cancer who had previously received or were not suitable to receive other treatments. The CORRELATE study showed that in the real world (i.e., outside of a controlled clinical trial), patients are sometimes prescribed regorafenib at lower starting doses than the recommended dose, without an apparent overall effect on how well regorafenib works or side effects. In the future, it will be important to continue researching how doctors prescribe regorafenib in daily clinical practice in Spain.

STELLAR-303: randomized phase III study of zanzalintinib + atezolizumab in previously treated metastatic colorectal cancer.

Most patients with metastatic colorectal cancer (mCRC) have limited treatment options following standard-of-care therapy. VEGFR-tyrosine kinase inhibitors (TKIs) have demonstrated clinical activity in mCRC in combination with immune checkpoint inhibitors (ICIs), particularly in patients without liver metastases. The TKI zanzalintinib (XL092) targets VEGFR, MET and TAM kinases, proteins that are involved in tumor growth, angiogenesis, metastasis and immunosuppression. Zanzalintinib has immunomodulatory properties that may enhance response to ICIs. Presented is the design of STELLAR-303, a global, phase III, open-label, randomized study evaluating zanzalintinib plus atezolizumab versus regorafenib in patients with non-MSI-H mCRC who progressed during/after or are refractory/intolerant to standard-of-care therapy. The primary end point is overall survival in patients without liver metastases.Clinical Trial Registration: NCT05425940 (ClinicalTrials.gov).

Metastatic colorectal cancer (mCRC) is cancer of the colon or rectum that has spread to other parts of the body, most often to the liver, lungs and abdomen. People with mCRC that has worsened after initial treatment have limited options. Zanzalintinib is a novel oral investigational drug that can slow or stop cancer growth. It works by blocking certain proteins that play important roles in the development, growth and spread of cancer. Zanzalintinib may also help improve the effectiveness of another class of cancer drugs called immune checkpoint inhibitors (ICIs), which work by activating the patient's immune system to fight cancer. Here, we describe the design of STELLAR-303, an ongoing study that is comparing the effects of combining zanzalintinib and an ICI drug called atezolizumab with an approved treatment for mCRC called regorafenib. About 900 participants with mCRC will be enrolled in the study worldwide. To be included in the study, participants must have mCRC that worsened after previous therapies and must not have a high level of microsatellite instability, which is a specific feature of some mCRCs. Participants will be randomly given one of the two treatments. The main goal of the study is to evaluate zanzalintinib plus atezolizumab compared with regorafenib by measuring the length of time participants are alive after starting treatment, specifically in patients with mCRC that has not spread to the liver. Additionally, the study will look at the side effects with each treatment. The study is currently seeking participants.

Regorafenib induces damage-associated molecular patterns, cancer cell death and immune modulatory effects in a murine triple negative breast cancer model.

Damage associated molecular patterns (DAMPs), including calreticulin (CRT) exposure, high-mobility group box 1 protein (HMGB1) elevation, and ATP release, characterize immunogenic cell death (ICD) and may play a role in cancer immunotherapy. Triple negative breast cancer (TNBC) is an immunogenic subtype of breast cancer with higher lymphocyte infiltration. Here, we found that regorafenib, a multi-target angiokinase inhibitor previously known to suppress STAT3 signaling, induced DAMPs and cell death in TNBC cells. Regorafenib induced the expression of HMGB1 and CRT, and the release of ATP. Regorafenib-induced HMGB1 and CRT were attenuated following STAT3 overexpression. In a 4T1 syngeneic murine model, regorafenib treatment increased HMGB1 and CRT expression in xenografts, and effectively suppressed 4T1 tumor growth. Immunohistochemical staining revealed increased CD4+ and CD8+ tumor-infiltrating T cells in 4T1 xenografts following regorafenib treatment. Regorafenib treatment or programmed death-1 (PD-1) blockade using anti-PD-1 monoclonal antibody reduced lung metastasis of 4T1 cells in immunocompetent mice. While regorafenib increases the proportion of MHC II high expression on dendritic cells in mice with smaller tumors, the combination of regorafenib and PD-1 blockade did not show a synergistic effect on anti-tumor activity. These results suggest that regorafenib induces ICD and suppresses tumor progression in TNBC. It should be carefully evaluated when developing a combination therapy with an anti-PD-1 antibody and a STAT3 inhibitor.

Exploring the effect of Wuzhi capsule on the pharmacokinetics of regorafenib and its main metabolites in rat plasma using liquid chromatography-tandem mass spectrometry.

Regorafenib is a small-molecule tyrosine kinase inhibitor with severe hepatotoxicity. It undergoes metabolism mainly by CYP3A4 to generate active metabolites regorafenib-N-oxide (M2) and N-desmethyl-regorafenib-N-oxide (M5). Wuzhi capsule (WZC) is an herbal preparation derived from Schisandra sphenanthera and is potentially used to prevent regorafenib-induced hepatotoxicity. This study aims to explore the effect of WZC on the pharmacokinetics of regorafenib in rats. An efficient and sensitive liquid chromatography-tandem mass spectrometry method was developed to quantitatively determine regorafenib and its main metabolites in rat plasma. The proposed method was applied to the pharmacokinetic study of regorafenib in rats, with or without WZC. Coadministration of regorafenib with WZC resulted in a prolonged mean residence time (MRT) of the parent drug but had no statistically significant difference in other pharmacokinetic parameters. While for the main metabolites of regorafenib, WZC decreased the area under the curve and maximum concentration (Cmax ), delayed the time to reach Cmax , and prolonged the MRT of M2 and M5. These results indicate that WZC delayed and inhibited the metabolism of regorafenib to M2 and M5 by suppressing CYP3A4. Our study provides implications for the rational use of the WZC-regorafenib combination in clinical practice.

Hyperammonemic encephalopathy after tyrosine kinase inhibitors: A literature review and a case example.

OBJECTIVE: To review the evidence of uncommon but fatal adverse event of hyperammonemic encephalopathy by tyrosine kinase inhibitors (TKI) and the possible mechanisms underlying this condition and to describe the case of a patient that developed drug-induced hyperammonemic encephalopathy related to TKI. DATA SOURCES: Literature search of different databases was performed for studies published from 1 January 1992 to 7 May 2023. The search terms utilized were hyperammonemic encephalopathy, TKI, apatinib, pazopanib, sunitinib, imatinib, sorafenib, regorafenib, trametinib, urea cycle regulation, sorafenib, carbamoyl-phosphate synthetase 1, ornithine transcarbamylase, argininosuccinate synthetase, argininosuccinate lyase, arginase 1, Mitogen activated protein kinases (MAPK) pathway and mTOR pathway, were used individually search or combined. DATA SUMMARY: Thirty-seven articles were included. The articles primarily focused in hyperammonemic encephalopathy case reports, management of hyperammonemic encephalopathy, urea cycle regulation, autophagy, mTOR and MAPK pathways, and TKI. CONCLUSION: Eighteen cases of hyperammonemic encephalopathy were reported in the literature from various multitargeted TKI. The mechanism of this event is not well-understood but some authors have hypothesized vascular causes since some of TKI are antiangiogenic, however our literature review shows a possible relationship between the urea cycle and the molecular inhibition exerted by TKI. More preclinical evidence is required to unveil the biochemical mechanisms responsible involved in this process and clinical studies are necessary to shed light on the prevalence, risk factors, management and prevention of this adverse event. It is important to monitor neurological symptoms and to measure ammonia levels when manifestations are detected.

COL5A2 drives regorafenib resistance-induced metastatic phenotype via reducing LIFR expression in hepatocellular carcinoma.

Systemic therapies, the ultimate strategies for patients with advanced hepatocellular carcinoma (HCC), are suffering from serious clinical challenges, such as the occurrence and development of drug resistance. Treatment resistance aggravates tumor progression partly by inducing tumor metastasis. Regorafenib-resistant HCC cells exhibit a highly striking metastatic phenotype, but the detailed mechanisms underlying these aggressive behaviors remain elusive. Here, we conduct transcriptome sequencing analysis to identify COL5A2 as a crucial driver of the metastatic characteristics of regorafenib-resistant HCC cells. COL5A2 is aberrantly highly expressed in resistant cells, and its genetic depletion significantly suppresses proliferation, migration, invasion, vasculogenic mimicry (VM) formation and lung metastasis in vitro and in vivo, concomitant with the downregulation of VE-cadherin, EphA2, Twist1, p-p38 and p-STAT3 expressions. LIFR is confirmed to be an essential downstream molecule of COL5A2, and its expression is observably elevated by COL5A2 depletion. Ectopic overexpression of LIFR drastically attenuates the proliferation, migration, invasion and VM of regorafenib-resistant cells and represses the expressions of VM-related molecules and the activation of p38/STAT3 signaling pathway. Interestingly, rescue experiments show that the inhibition of the above aggressive features of resistant cells by COL5A2 loss is clearly alleviated by silencing of LIFR. Collectively, our results reveal that COL5A2 promotes the ability of regorafenib-resistant HCC cells to acquire a metastatic phenotype by attenuating LIFR expression and suggest that therapeutic regimens targeting the COL5A2/LIFR axis may be beneficial for HCC patients with therapeutic resistance.

Formulation, development and evaluation of hyaluronic acid-conjugated liposomal nanoparticles loaded with regorafenib and curcumin and their in vitro evaluation on colorectal cancer cell lines.

Colorectal cancer is one of the major causes of global cancer, with chemotherapy and radiation therapy being effective but limited due to low specificity. Regorafenib, a multikinase inhibitor, provides hope to patients with metastatic colorectal cancer and was approved by the FDA in 2012. However, due to resistance issues and adverse events, its efficacy is compromised, necessitating further refinement. Meanwhile, curcumin, a compound of turmeric, exhibits anticancer effects through antioxidant and anti-inflammatory actions, induction of the apoptosis, arrest of cell cycle, inhibition of angiogenesis, and modulation of signaling pathways. Unfortunately, its clinical utility is limited by its poor bioavailability, pointing towards innovative drug delivery strategies for enhanced efficacy in colorectal cancer treatment. Hyaluronic acid (HA)-decorated liposomes (LIPO) have been developed to target colorectal cells through an overexpressed CD44 receptor, increasing antitumor and antimetastasis efficacy. This study investigates the possibility of loading curcumin (CUR) or regorafenib (REGO) into a liposomal formulation for passive and HA-actively targeted treatment, evaluating its critical quality attributes (CQA) (size, zeta potential, polydispersity index) and cytotoxic activity in the HT29 colorectal cancer cell line. The average particle size of the plain liposomes and those decorated with HA was 144.00 ± 0.78 nm and 140.77 ± 1.64 nm, respectively. In contrast, curcumin-loaded plain liposomes and HA-decorated liposomes had 140 ± 2.46 nm and 164.53 ± 15.13 nm, respectively. The prepared liposomes had a spherical shape with a narrow size distribution and an acceptable zeta potential of less than -30 mV. The encapsulation efficiency was 99.2 % ± 0.3 and 99.9 ± 0.2 % for HA-decorated and bare regorafenib loaded. The % EE was 98.9 ± 0.2 % and 97.5 ± 0.2 % for bare liposomal nanoparticles loaded with curcumin and coated with curcumin. The IC50 of free REGO, CUR, REGO-LIPO, CUR-LIPO, REGO-LIPO-HA and CUR-LIPO-HA were 20.17 ± 0.78, 64.4 ± 0.33, 224.8 ± 0.06, 49.66 ± 0.22, 73.66 ± 0.6, and 27.86 ± 0.49 µM, respectively. The MTT assay in HT29 cells showed significant cytotoxic activity of the HA-decorated liposomal formulation compared to the base uncoated formulation, indicating that hyaluronic acid-targeted liposomes loaded with regorafenib or curcumin could be a promising targeted formulation against colorectal cancer cells.

REGISTRI: Regorafenib in first-line of KIT/PDGFRA wild type metastatic GIST: a collaborative Spanish (GEIS), Italian (ISG) and French Sarcoma Group (FSG) phase II trial.

BACKGROUND: Approximately 15% of adult GIST patients harbor tumors that are wild-type for KIT and PDGFRα genes (KP-wtGIST). These tumors usually have SDH deficiencies, exhibit a more indolent behavior and are resistant to imatinib. Underlying oncogenic mechanisms in KP-wtGIST include overexpression of HIF1α high IGFR signaling through the MAPK pathway or BRAF activating mutation, among others. As regorafenib inhibits these signaling pathways, it was hypothesized that it could be more active as upfront therapy in advanced KP-wtGIST. METHODS: Adult patients with advanced KP-wtGIST after central confirmation by NGS, naïve of systemic treatment for advanced disease, were included in this international phase II trial. Eligible patients received regorafenib 160 mg per day for 21 days every 28 days. The primary endpoint was disease control rate (DCR), according to RECIST 1.1 at 12 weeks by central radiological assessment. RESULTS: From May 2016 to October 2020, 30 patients were identified as KP-wtGIST by Sanger sequencing and 16 were confirmed by central molecular screening with NGS. Finally, 15 were enrolled and received regorafenib. The study was prematurely closed due to the low accrual worsened by COVID outbreak. The DCR at 12 weeks was 86.7% by central assessment. A subset of 60% experienced some tumor shrinkage, with partial responses and stabilization observed in 13% and 87% respectively, by central assessment. SDH-deficient GIST showed better clinical outcome than other KP-wtGIST. CONCLUSIONS: Regorafenib activity in KP-wtGIST compares favorably with other tyrosine kinase inhibitors, especially in the SDH-deficient GIST subset and it should be taken into consideration as upfront therapy of advanced KP-wtGIST. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02638766.