Toxicity of sorafenib: clinical and molecular aspects

Protective effect of deinoxanthin in sorafenib-induced nephrotoxicity in rats with the hepatocellular carcinoma model

Sorafenib is a synthetic compound and an orally administered multichines inhibitor that targets growth signaling and angiogenesis. It is widely recognized as the standard of care for advanced hepatocellular carcinoma (HCC) but has toxic side effects. Deinoxanthin, purified from the radioresistant bacterium Deinococcus radiodurans, has strong antioxidant characteristics. In this study, the protective effect of deinoxanthin against sorafenib-induced nephrotoxicity was investigated in a rat model of hepatocellular carcinoma. In this regard, the expressions of DDAH1, KIM1, and INOS genes were examined, histopathological and immunohistochemical analyses were performed, and various parameters such as SOD, MDA, GST, CAT, TAS, and TOS were tested biochemically. BUN and creatinine levels were measured in renal tissues. RT-qPCR, Western blot, and ELISA methods were used for all these analyses. As a result, the analyses show that deinoxanthin, which has a high antioxidant capacity, reduces kidney injury and can be used as a protective agent. The primary objective of this study is to evaluate the potential of deinoxanthin as a protective agent against the nephrotoxic side effects of sorafenib in HCC. Our study identified the potential synergistic effects of sorafenib and deinoxanthin on nephrotoxicity in rats with hepatocellular carcinoma.

Tyrosine kinase inhibitor maintenance therapy after stem cell transplantation for FLT3-mutated acute myeloid leukemia

OBJECTIVES

This is a protocol for a Cochrane Review (intervention). The objectives are as follows: To assess the effects of FLT3 TKIs as maintenance therapy compared to no maintenance therapy or alternative strategies for participants with FLT3-mutated AML after allo-HSCT.

Remodeling of sorafenib as an orally bioavailable ferroptosis inducer for Lung Cancer by chemical modification of adenine-binding motif

Sorafenib (BAY 43-9006) was developed as a multi-kinase inhibitor to treat advanced renal cell, hepatocellular, and thyroid cancers. The cytotoxic effect of sorafenib on cancer cells results from not only inhibiting the MEK/ERK signaling pathway (the on-target effect) but also inducing oxidative damage (the off-target effect). The inhibitory effect of sorafenib on system Xc- (xCT), a cystine/glutamate antiporter, promotes ferroptosis induction and accounts for oxidative damage. While emerging studies on ferroptosis in cancers have garnered increasing attention, the lack of consideration for ferroptosis inducers (FINs) with favorable pharmacokinetics could be problematic. Herein, we remodeled the chemical structure of sorafenib, of which pharmacokinetics and safety are already assured, to customize the off-target effect (i.e., ferroptosis induction) to on-target by disrupting the adenine-binding motif. JB3, a sorafenib derivative (i.e., JB compounds), with a tenfold higher IC50 toward RAF1 because of chemical remodeling, induced strong cytotoxicity in the elastin-sensitive lung cancer cells, while it was markedly reduced by ferrostatin-1. The 24% oral bioavailability of JB3 in rats accounted for a significant anti-tumor effect of orally administrated JB3 in xenograft models. These results indicate that JB3 could be further developed as an orally bioavailable FIN in novel anti-cancer therapeutics.

A Novel Combinatorial Regimen Using Sorafenib and Uttroside B, A US FDA-designated 'Orphan Drug', for the Treatment of Hepatocellular Carcinoma

INTRODUCTION

Sorafenib (Sor) is the first-line treatment option in clinics for treating advanced unresectable hepatocellular carcinoma (HCC). However, acquired chemoresistance and adverse side effects associated with Sor monotherapy limit its clinical benefits. We have previously reported the exceptional anti-HCC potential of uttroside B (Utt-B), a furostanol saponin isolated in our lab from Solanum nigrum Linn. leaves. The current study has evaluated the supremacy of a combinatorial regimen of Sor and Utt-B over Sor monotherapy.

METHODS

MTT assay was used for In vitro cytotoxicity studies. A clonogenic assay was conducted to assess the anti-proliferative effect of the combination. Annexin V/PI staining, confocal microscopy, FACS cell cycle analysis, and Western blotting experiments were performed to validate the pro-apoptotic potential of the combination in HepG2 and Huh7 cell lines. Pharmacological safety evaluation was performed in Swiss albino mice.

RESULTS

Our results indicate that Utt-B augments Sor-induced cytotoxicity in HepG2 and Huh7 cells. The combination inhibits the proliferation of liver cancer cells by inducing apoptosis through activation of the caspases 7 and 3, leading to PARP cleavage. Furthermore, the combination does not induce any acute toxicity in vivo, even at a dose five times that of the effective therapeutic dose.

CONCLUSION

Our results highlight the potential of Utt-B as an effective chemosensitizer, which can augment the efficacy of Sor against HCC and circumvent Sor-induced toxic side effects. Moreover, this is the first and only report to date on the chemosensitizing potential of Utt-B and the only report that demonstrates the therapeutic efficacy and pharmacological safety of a novel combinatorial regimen involving Utt-B and Sor for combating HCC.

The Effects of Drug Exposure and Single Nucleotide Polymorphisms on Aaptinib-Induced Severe Toxicities in Solid Tumors

To investigate the value of drug exposure and host germline genetic factors in predicting apatinib (APA)-related toxicities.

METHOD

In this prospective study, plasma APA concentrations were quantified using liquid chromatography with tandem mass spectrometry, and 57 germline mutations were genotyped in 126 advanced solid tumor patients receiving 250 mg daily APA, a vascular endothelial growth factor receptor II inhibitor. The correlation between drug exposure, genetic factors, and the toxicity profile was analyzed.

RESULTS

Non-small cell lung cancer (NSCLC) was more prone to APA-related toxicities and plasma concentrations of APA, and its main metabolite M1-1 could be associated with high-grade adverse events (AEs) (P < 0.01; M1-1, P < 0.01) and high-grade antiangiogenetic toxicities (APA, P = 0.034; P < 0.05), including hypertension, proteinuria, and hand-foot syndrome, in the subgroup of NSCLC. Besides, CYP2C9 rs34532201 TT carriers tended to have higher levels of APA (P < 0.001) and M1-1 (P < 0.01), whereas CYP2C9 rs1936968 GG carriers were predisposed to higher levels of M1-1 (P < 0.01).

CONCLUSION

Plasma APA and M1-1 exposures were able to predict severe AEs in NSCLC patients. Dose optimization and drug exposure monitoring might need consideration in NSCLC patients with CYP2C9 rs34532201 TT and rs1936968 GG.

SIGNIFICANCE STATEMENT

Apatinib is an anti-VEGFR2 inhibitor for the treatment of multiple cancers. Though substantial in response, apatinib-induced toxicity has been a critical issue that is worth clinical surveillance. Few data on the role of drug exposure and genetic factors in apatinib-induced toxicity are available. Our study demonstrated a distinct drug-exposure relationship in NSCLC but not other tumors and provided invaluable evidence of drug exposure levels and single nucleotide polymorphisms as predictive biomarkers in apatinib-induced severe toxicities.

FLT3 inhibitors as maintenance therapy post allogeneic hematopoietic stem cell transplantation in acute myeloid leukemia patients with FLT3 mutations: A meta-analysis

BACKGROUND

Acute myeloid leukemia (AML) patients with a Fms-like tyrosine kinase 3 (FLT3) mutation have a high incidence of relapse despite allogeneic hematopoietic stem cell transplantation (allo-HSCT) and a subsequent poor prognosis. FLT3 inhibitors (FLT3i) have been suggested to reduce the post-transplant relapse risk in recent studies. As more evidence is accumulated, we perform the present meta-analysis to assess the efficacy and safety of FLT3i as post-transplant maintenance therapy in AML patients.

METHODS

Literature search was performed in public databases from inception to December 31, 2021. Overall survival (OS), relapse-free survival (RFS), cumulative incidence of relapse (CIR), non-relapse mortality (NRM), graft-versus-host disease (GVHD) and adverse events were compared between FLT3i and control groups. Pooled hazard ratio (HR) or relative risk (RR) with corresponding 95% confidence interval (CI) were calculated.

RESULTS

We identified 12 eligible studies with 2282 FLT3-mutated AML patients who had received HSCT. There was no between-study heterogeneity and a fix-effect model was used. Post-transplant FLT3i maintenance significantly prolonged OS (HR = 0.41, 95%CI: 0.32-0.52, p < 0.001) and RFS (HR = 0.39, 95%CI 0.31-0.50, p < 0.001), and reduced CIR (HR = 0.31, 95%CI 0.20-0.46, p < 0.001) as compared with control. There were no significant risk differences in NRM (RR = 0.69, 95%CI 0.41-1.17, p = 0.169), acute GVHD (RR = 1.17, 95%CI 0.93-1.47, p = 0.175), chronic GVHD (RR = 1.31, 95%CI 0.91-1.39, p = 0.276) and grade ≥3 adverse events between both groups, except for skin toxicity (RR = 5.86, 95%CI 1.34-25.57, p = 0.019).

CONCLUSION

Post-transplant FLT3i maintenance can improve survival and reduce relapse in FLT3-mutated AML patients and is tolerable.

Evaluation of Delayed-Type Hypersensitivity to Antineoplastic Drugs-An Overview

Nowadays, clinical practice encounters the problem of delayed-type hypersensitivity (DTH) induced by several drugs. Antineoplastic treatments are among the drugs which show an elevated proportion of DHT reactions, leading to the worsening of patients' quality of life. The range of symptoms in DHT reactions can vary from mild, such as self-limiting maculopapular eruptions, to severe, such as Stevens-Johnson Syndrome. The development of these reactions supposes a negative impact, not only by limiting patients' quality of life, but also leading to economic loss due to market withdrawal of the affected drugs and high hospitalization costs. However, despite this problem, there are no available standard in vitro or in vivo methods that allow for the evaluation of the sensitizing potential of drugs in the preclinical phase. Therefore, the aim of this review is to summarize the skin reactions caused by the different antineoplastic families, followed by a comprehensive evaluation of the in vitro and in vivo methods used to detect DTHs and that could be suitable to test antineoplastic hypersensitivity reactions.

Neurogenic orthostatic hypotension after treatment with sorafenib

A man in his 70s with a history of fatigue, abdominal pain, and a palpable abdominal mass was found to have a peritoneal desmoid tumour. One year after diagnosis, he was prescribed sorafenib to limit tumour growth. Two months later, he developed dyspnoea on exertion and lower extremity weakness and was reported to have supine hypertension and orthostatic hypotension. On formal autonomic testing, he was noted to have severely impaired sympathetic responses and marked orthostatic hypotension without appropriate chronotropic response. A decision to hold sorafenib was made, and treatment was started with graduated compression stockings, liberal fluid and sodium intake, and midodrine. The patient had a modest and gradual improvement in his symptoms. To our knowledge, this is the first reported case of orthostatic hypotension related to sorafenib or any vascular endothelial growth factor inhibitors.

Design and synthesis of novel ureido and thioureido conjugated hydrazone derivatives with potent anticancer activity

Background

Compounds possessing urea/thiourea moiety have a wide range of biological properties including anticancer activity. On the other hand, taking advantage of the low toxicity and structural diversity of hydrazone derivatives, they are presently being considered for designing chemical compounds with hydrazone moiety in the field of cancer treatment. With this in mind, a series of novel ureido/thioureido derivatives possessing a hydrazone moiety bearing nitro and chloro substituents (4a–4i) have been designed, synthesized, characterized and evaluated for their in vitro cytotoxic effect on HT-29 human colon carcinoma and HepG2 hepatocarcinoma cell lines.

Results

Two compounds (4c and 4e) having the chloro phenylurea group hybridized with phenyl hydrazone bearing nitro or chloro moieties demonstrated potent anticancer effect with the IC₅₀ values between 2.2 and 4.8 µM at 72 h. The mechanism of action of compound 4c was revealed in hepatocellular carcinoma cells as an inducer of apoptosis in a caspase-independent pathway.

Conclusion

Taken together, the current work presented compound 4c as a potential lead compound in developing future hepatocellular carcinoma chemotherapy drugs.

Methods

The compounds were synthesized and then characterized by physical and spectral data (FT-IR, ¹H-NMR, ¹³C-NMR, Mass). The anticancer activity was assessed using MTT assay, flowcytometry, annexin-V, DAPI staining and Western blot analysis.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13065-022-00873-3.

Stereotactic ablative radiotherapy for pulmonary oligometastases from primary hepatocellular carcinoma: a multicenter and retrospective analysis (KROG 17-08)

OBJECTIVE

Hypofractionated radiotherapy has recently been applied to treat pulmonary metastases of hepatocellular carcinoma. However, there is no definite evidence on its safety and efficacy. We evaluate the clinical outcomes of hypofractionated radiotherapy for oligo pulmonary metastases of hepatocellular carcinoma in the multicenter and retrospective study.

METHODS

From March 2011 to February 2018, 58 patients with fewer than five pulmonary metastases of hepatocellular carcinoma who underwent hypofractionated radiotherapy in nine tertiary university hospitals were analyzed retrospectively. The primary endpoint was the local control rate. The secondary endpoints were overall survival, progression-free survival, prognostic factors affecting the treatment outcomes and treatment-related side effects.

RESULTS

The local tumor response rate including complete and partial response was 77.6% at 3 months after hypofractionated radiotherapy. The median survival and progression-free survival times were 20.9 and 5.3 months, respectively. The 1-year overall survival and progression-free survival rates were 65.5 and 22.4%, respectively. The good treatment response after hypofractionated radiotherapy (P = 0.001), the absence of intrahepatic tumor (P = 0.004) and Child-Pugh class A (P = 0.010) were revealed as significant prognostic factors for overall survival in the multivariate analysis. A progression-free interval of <6 months (P = 0.009) was a negative prognostic factor for overall survival in the multivariate analysis. Of 58 patients, five (8.6%) had grade 2 or higher radiation pneumonitis after hypofractionated radiotherapy.

CONCLUSIONS

The favorable local control rate and acceptable toxicity indicate the clinical usefulness of hypofractionated radiotherapy for hepatocellular carcinoma patients who have less than five pulmonary metastases.

Sorafenib-related generalized eruptive keratoacanthomas (Grzybowski syndrome): a case report

BACKGROUND

Sorafenib is an oral multikinase inhibitor that targets Raf serine/threonine receptor tyrosine kinases and inhibits tumor cell growth and angiogenesis. Cutaneous toxicities of sorafenib are common, including cutaneous eruptions (such as truncal erythema and seborrheic-dermatitis-like changes) and hand-foot syndrome. Keratoacanthomas and squamous cell carcinomas have been reported previously; however, we report a case of multiple eruptive keratoacanthomas in the form of Grzybowski syndrome after initiation of sorafenib.

CASE PRESENTATION

We report a 63-year-old Caucasian male who developed multiple cutaneous eruptive keratoacanthomas after starting sorafenib 400 mg twice daily. He had a known history of hepatitis-C-related cirrhosis and hepatocellular carcinoma, and previously had actinic keratosis and skin squamous cell carcinoma excision. Approximately two and a half months after starting sorafenib, the patient initially developed two lesions, one on each forearm, and after excision, these lesions demonstrated histological features of squamous cell carcinoma. One month later, the patient presented with approximately 48 new skin lesions of varying size on the back, bilateral upper limbs, and face requiring excisional biopsy of a large number of these lesions. Histopathology showed eruptive invasive keratoacanthomas (Grzybowski syndrome). Sorafenib was temporarily stopped and subsequently restarted at a lower dose. Acitretin 25 mg daily was commenced after few weeks, and no further keratoacanthomas developed during his treatment.

CONCLUSIONS

We report a unique case of sorafenib-associated Grzybowski syndrome. Temporary interruption and dose reduction of sorafenib and use of acitretin appeared to prevent further development of keratoacanthomas.

Safety of FLT3 inhibitors in patients with acute myeloid leukemia

Introduction: Acute myeloblastic leukemia (AML) is the most frequent type of acute leukemia in adults with an incidence of 4.2 cases per 100,000 inhabitants and poor 5-year survival. Patients with mutations in the FMS-like tyrosine kinase 3 (FLT3) gene have poor survival and higher relapse rates compared with wild-type cases.Areas covered: Several FLT3 inhibitors have been proved in FLT3^mut AML patients, with differences in their pharmacokinetics, kinase inhibitory and adverse events profiles. First-generation multi-kinase inhibitors (midostaurin, sorafenib, lestaurtinib) target multiple proteins, whereassecond-generation inhibitors (crenolanib, quizartinib, gilteritinib) are more specific and potent inhibitors of FLT3, so they are associated with less off-target toxic effects. All of these drugs have primary and acquired mechanisms of resistance, and therefore their combinations with other drugs (checkpoint inhibitors, hypomethylating agents, standard chemotherapy) and its application in different clinical settings are under study.Expert opinion: The recent clinical development of various FLT3 inhibitors for the treatment of FLT3^mut AML is an effective therapeutic strategy. However, there are unique toxicities and drug-drug interactions that need to be resolved. It is necessary to understand the mechanisms of toxicity in order to recognize and manage them adequately.

A novel bis-aryl urea compound inhibits tumor proliferation via cathepsin D-associated apoptosis

Supplemental Digital Content is available in the text.

Derivatives of bis-aryl urea have been widely investigated for their various biological activities, such as antiviral, anti-inflammatory and antiproliferative. We evaluated a new chemical entity consisting of bis-aryl urea moiety, N69B, for its anticancer activities and explored their underlying molecular mechanism. The compound inhibited proliferation of multiple types of murine and human cancer cells in vitro, and reduced tumor growth in mouse 4T1 breast tumor model in vivo. Protein microarray analysis revealed and western blot confirmed that the compound significantly increased protein levels of cathepsins, especially cathepsin D, a lysosomal aspartyl protease known to have various pathophysiological functions. Further studies showed that the compound induced tumor cell apoptosis through the Bid/Bax/Cytochrome C/caspase 9/caspase 3 pathway, in which cathepsin D appeared to be a main mediator. Unlike kinase inhibition commonly seen with many other anticancer bis-aryl urea derivatives, this unique mechanism of N69B may suggest potential of the compound as a novel anticancer drug.

Outcomes in hepatocellular carcinoma patients undergoing sorafenib treatment: toxicities, cellular oxidative stress, treatment adherence, and quality of life

The study of toxicities induced by sorafenib, as well as the identification of possible mechanisms and biomarkers of these toxicities, is important to improve the treatment and quality of life of hepatocellular carcinoma (HCC) patients. This study focused on toxicities, cellular oxidative stress, adherence, and quality of life of 11 patients with HCC treated with sorafenib. Dermatotoxicity, myelotoxicity, gastro toxicity, nephrotoxicity, pain, and fatigue were investigated. For oxidative stress analysis, the peripheral blood mononuclear cells were isolated and mitochondrial superoxide anion production was measured using MitoSOX Red test. Medication adherence was evaluated based on Morisky-Green and MedTake tests. Quality of life assessment was performed using EORTC QLQ C-30 and QLQ HCC18 questionnaires. The results showed that hand-foot syndrome (45.5%), thrombocytopenia (45.5%), diarrhea (54.5%), pain (54.5%), and fatigue (36.4%) were the most prevalent toxicities. A non-statistically significant change in the levels of superoxide anion was observed after the sorafenib treatment (Wilcoxon test, P = 0.4131). Moreover, 81.8% of patients had high adherence, 100% knew the correct indication of sorafenib, 81.8% knew the correct intake and drug regimen, and 36.4% knew the correct dose of antineoplastic. There was a significant worsening in the emotional and pain domains of quality of life after the sorafenib (Wilcoxon test, P = 0.0313 and P = 0.0313, respectively). A production of superoxide anion was not correlated with toxicities (Spearman's correlation and Mann-Whitney U tests, P > 0.05). This study suggests that oxidative stress might not be the mechanism of sorafenib toxicities.

Pharmacogenetics and pharmacokinetics modeling of unexpected and extremely severe toxicities after sorafenib intake

A 53-year-old woman with papillary thyroid cancer treated with 800 mg sorafenib therapy rapidly experienced grade 3 toxicities. Dosing was reduced in a step-wise manner with several treatment discontinuations down to 200 mg every 2 days but severe toxicities continued. Plasma drug monitoring showed high exposure, even at low dose. Dosing was then further reduced at 200 mg every 3 days and tolerance was finally acceptable (i.e., grade 1 toxicity) with stable disease upon RECIST imaging. Pharmacogenetic investigations showed polymorphisms affecting both UGT1A9 (UGT1A9-rs3832043) and nuclear receptor PXR (NR1I2-rs3814055, NR1I2-rs2472677 and NR1I2-rs10934498), possibly resulting in downregulation of liver metabolizing enzymes of sorafenib (i.e., CYP and UGT). Patient's clearance (0.48 l/h) estimated by Bayesian approach was consistently lower than usually described. This is the first time that, in addition to mutations affecting UGT1A9, genetic polymorphisms of NR1I2 have possibly been associated with both plasma overexposure and severe toxicities upon sorafenib intake.

The safety and efficacy of TACE combined with apatinib on patients with advanced hepatocellular carcinoma: a retrospective study

As a novel vascular endothelial growth factor receptor-2 tyrosine kinase inhibitor (VEGFR2-TKI), apatinib has a certain anti-tumor effect for a variety of solid tumors. The present study evaluates its efficacy and safety in advanced hepatocellular carcinoma (HCC). In this study, 47 patients with advanced HCC were included. TACE monotherapy group included 22 patients that responded to TACE, while the group that received TACE and apatinib included 25 patients that progressed on TACE and were able to receive apatinib off label. Median overall survival (OS) was significantly improved in the apatinib plus TACE group compared with the TACE group. Similarly, apatinib in combination with TACE significantly prolonged median progression-free survival (PFS) compared with TACE monotherapy. Furthermore, there was a significant difference between combination therapy and monotherapy in both Barcelona clinic liver cancer (BCLC) B and BCLC C group. The combination therapy had a dramatic effect on OS and PFS for patients at both BCLC B and BCLC C level. The most common clinically adverse events of apatinib plus TACE group were fatigue, weight loss, hypertension, hand-foot syndrome and anorexia, which were manageable and tolerable. The efficacy analysis showed that there was no significant association of survival benefit with age, gender, Eastern Cooperative Oncology Group (ECOG) performance status, hypertension and hand-foot syndrome. Patients with macrovascular invasion and extrahepatic invasion showed worse survival benefits. In conclusion, apatinib combined with TACE revealed certain survival benefits for HCC patients who experienced progression following TACE, which can provide a promising strategy for HCC treatment.

Severe cutaneous adverse reactions induced by targeted anticancer therapies and immunotherapies

With the increasing use of targeted anticancer drugs and immunotherapies, there have been a substantial number of reports concerning life-threatening severe cutaneous adverse reactions (SCARs), including Stevens–Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug rash with eosinophilia and systemic symptoms, drug-induced hypersensitivity syndrome, and acute generalized exanthematous pustulosis. Although the potential risks and characteristics for targeted anticancer agent- and immunotherapy-induced SCAR were not well understood, these serious adverse reactions usually result in morbidity and sequela. As a treatment guideline for this devastating condition is still unavailable, prompt withdrawal of causative drugs is believed to be a priority of patient management. In this review, we outline distinct types of SCARs caused by targeted anticancer therapies and immunotherapies. Also, we discuss the clinical course, latency, concomitant medication, tolerability of rechallenge or alternatives, tumor response, and mortality associated with these devastating conditions. Imatinib, vemurafenib, and rituximab were the top three offending medications that most commonly caused SJS/TEN, while EGFR inhibitors were the group of drugs that most frequently induced SJS/TEN. For drug rash with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome and acute generalized exanthematous pustulosis, imatinib was also the most common offending drug. Additionally, we delineated 10 SCAR cases related to innovative immunotherapies, including PD1 and CTLA4 inhibitors. There was a wide range of latency periods: 5.5–91 days (median). Only eight of 16 reported patients with SCAR showed clinical responses. Targeted anticancer drugs and immunotherapies can lead to lethal SCAR (14 deceased patients were identified as suffering from SJS/TEN). The mortality rate of TEN was high: up to 52.4%. The information compiled herein will serve as a solid foundation to formulate ideas for early recognition of SCAR and to discontinue offending drugs for better management.

miR-199a-3p Modulates MTOR and PAK4 Pathways and Inhibits Tumor Growth in a Hepatocellular Carcinoma Transgenic Mouse Model

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death worldwide. Prognosis is poor, and therapeutic options are limited. MicroRNAs (miRNAs) have emerged as potential therapeutic molecules against cancer. Here, we investigated the therapeutic efficacy of miR-199a-3p, an miRNA highly expressed in normal liver and downregulated in virtually all HCCs. The therapeutic value of miR-199a-3p mimic molecules was assayed in the TG221 mouse, a transgenic model highly predisposed to the development of liver cancer. Administration of miR-199a-3p mimics in the TG221 transgenic mouse showing liver cancer led to a significant reduction of number and size of tumor nodules compared to control animals. In vivo delivery confirmed protein downregulation of the miR-199a-3p direct targets, mechanistic target of rapamycin (MTOR) and p21 activated kinase 4 (PAK4), ultimately leading to the repression of FOXM1. Remarkably, the anti-tumor activity of miR-199a-3p mimics was comparable to that obtained with sorafenib. These results suggested that miR-199a-3p may be considered a promising HCC therapeutic option.

Anticancer Drugs Induced Severe Adverse Cutaneous Drug Reactions: An Updated Review on the Risks Associated with Anticancer Targeted Therapy or Immunotherapies

Cutaneous adverse drug reactions are commonly seen in patients with anticancer drug treatment. Anticancer drugs, including chemotherapy, target therapy, and recent immunotherapy causing skin reactions ranging from mild skin rash to life-threatening severe cutaneous adverse reactions (SCARs), such as Stevens-Johnson syndrome (SJS) and toxic epidermal necrosis (TEN) with increase morbidity and mortality while they are receiving cancer treatments, have been proposed to be a result of direct skin toxicity or drug hypersensitivity reactions (these are proposed mechanism, not definite). Differentiating SCARs from other more commonly seen reactions with a better outcome help prevent discontinuation of therapy and inappropriate use of systemic immunosuppressants for presumable allergic reactions, of which will affect the clinical outcome. In this article, we have reviewed published articles from 1950 to August 2017 for SJS/TEN associated with anticancer drugs, including chemotherapy, targeted therapy, and immunotherapy. We aimed to provide an overview of SJS/TEN associated with anticancer drugs to increase clinician recognition and accelerate future studies on the pathomechanism and managements.

Cyclodextrin polymers as nanocarriers for sorafenib

Polymeric nanoparticles based on cyclodextrins are currently undergoing clinical trials as new promising nanotherapeutics. In light of this interest, we investigated cyclodextrin cross-linked polymers with different lengths as carriers for the poorly water-soluble drug sorafenib. Both polymers significantly enhanced sorafenib solubility, with shorter polymers showing the most effective solubilizing effect. Inclusion complexes between sorafenib and the investigated polymers exhibited an antiproliferative effect in tumor cells similar to that of free sorafenib. Polymer/Sorafenib complexes also showed lower in vivo tissue toxicity than with free sorafenib in all organs. Our results suggest that the inclusion of sorafenib in polymers represents a successful strategy for a new formulation of this drug.

In vitro Anti-Proliferative Effect of Tephrosia purpurea on Human Hepatocellular Carcinoma Cells

Background:

Tephrosia purpurea is an Indian herb used in traditional medicine to treat various diseases such as jaundice, asthma, liver and urinary disorders. However, the anti-cancer potential of T. purpurea on hepatocellular carcinoma (HCC) is poorly understood. Therefore, this study aims to investigate the anti-cancer activity of T. purpurea in HepG2 hepatocellular carcinoma cells.

Methods:

The leaves and root of T. purpurea were extracted with methanol using soxhlet apparatus. The cytotoxicity of the T. purpurea extracts in HepG2 cells was evaluated using MTT assay whereas the mode of cell death was examined by AOEB, Hoechst and JC1 staining under a fluorescence microscope. T. purpurea extracts-induced caspase-3 expression was investigated using colorimetric assay.

Results:

The leaves and root extracts inhibited HepG2 cell growth at the IC₅₀ of 102.33 ± 10.26 µg/mL and 276.67 ± 20.43 µg/mL respectively at 24 h. Chromatin condensation, nuclear fragmentation, apoptotic bodies formation and mitochondrial membrane depolarization were observed in HepG2 cells treated with both extracts. The caspase-3 expression was significantly (p < 0.05) increased in extracts treated cells when compared to control.

Conclusion:

The leaves and root extracts of T. purpurea induce apoptosis mediated cell death in HepG2 cells.

SUMMARY

The leaves and root extracts of T. purpurea exhibited anticancer activity in HepG2 hepatocellular carcinoma cells. These extracts induced cell shrinkage, DNA condensation and fragmentation, mitochondrial membrane depolarization and upregulated caspase-3 expression indicating T. purpurea extracts induce apoptosis in HepG2 cells.

Abbreviation used: AO: acridine orange, DMSO: dimethyl sulfoxide, EB: ethidium bromide, IC50: the concentration at which 50% of cancer cells are dead, JC-1: 5, 5’, 6, 6’-tetrachloro-1, 1’, 3, 3’-tetraethyl-imidacarbocyanine iodide, MTT: 3-4, 5-dimethylthiazole-2-yl, 2,5-diphenyl tetrazolium bromide, PBS: phosphate-buffered saline, ΔΨm: mitochondrial trans-membrane potential.

Osteonecrosis of the Jaw during Sorafenib Therapy for Hepatocellular Carcinoma

Introduction

Sorafenib is an oral multiple tyrosine kinase inhibitor and is currently the only evidence-based treatment recommended for advanced hepatocellular carcinoma. We report a case of osteonecrosis of the jaw that occurred during sorafenib therapy in a patient with advanced hepatocellular carcinoma not treated with bisphosphonates or other antiangiogenic drugs.

Methods

A systematic search in PubMed yielded some cases of osteonecrosis of the jaw in patients treated with antiangiogenic agents, alone or in combination with bisphosphonates, for metastatic renal cell carcinoma. The only case of osteonecrosis observed during sorafenib therapy not combined with other predisposing agents was described by Guillet et al.

Results

A 74-year-old man diagnosed with hepatocellular carcinoma ensuing in hepatitis C virus infection, who was treated with sorafenib at a daily dose of 400 mg, developed osteonecrosis of the right mandibular body. The lesion was documented by a dental CT scan and surgical evaluation did not lead to an indication for curettage treatment. Sorafenib was discontinued because of the radiological and laboratory features of hepatocellular carcinoma progression and the high risk of jaw fracture.

Conclusions

To our knowledge, this is the first description of osteonecrosis of the jaw detected in a cirrhotic patient on sorafenib therapy not combined with bisphosphonates.

Receptor Tyrosine Kinase Phosphorylation Pattern-Based Multidrug Combination Is an Effective Approach for Personalized Cancer Treatment

Receptor tyrosine kinases (RTK) are key signaling molecules in regulating cancer cell growth and are important cancer drug targets. Despite the success of specific RTK-targeting therapy in certain cancer treatments, the overall response rates are limited to the drug target-stratified populations. We have systematically studied RTK activations in a panel of cancer cell lines, primary cancers, and cancer xenografts and found that different combinations of RTKs were activated in different cancer cells regardless of their tissue origins. Combinations of specific RTK inhibitors (RTKi) preferentially inhibited proliferation of the cancer cells with corresponding RTK activation profiles. We also found that the activations of RTKs were regulated by both cell-autonomous and environment-dependent mechanisms and demonstrated that inhibition of all activated RTKs was essential to completely block cancer cell proliferation. In addition, c-Myc downregulation was identified as an indicator for the effectiveness of the RTKi combination treatments. Our findings demonstrated that the RTK activation profile is a valid biomarker for diagnosis and stratification of cancers, and a corresponding combination of RTKis is a promising strategy to treat cancers, particularly the single RTKi therapy-resistant cancers, selectively and effectively. Mol Cancer Ther; 15(10); 2508-20. ©2016 AACR.

Managing Cutaneous Side Effects From Targeted Molecular Inhibitors for Melanoma and Nonmelanoma Skin Cancer

BACKGROUND

Targeted anticancer therapies can cause cutaneous adverse events different from classical chemotherapeutic toxicities.

OBJECTIVE

To review the literature on dermatologic adverse events (DAEs) of targeted molecular inhibitors for melanoma and nonmelanoma skin cancers with a focus on management options.

MATERIALS AND METHODS

A comprehensive literature search related to the side effects and management of these side effects from vemurafenib, dabrafenib, trametinib (BRAF inhibitors), pembrolizumab (antiprogrammed-death-receptor-1 antibody), imatinib (tyrosine kinase inhibitor), ipilimumab (anticytotoxic T-lymphocyte antigen-4 antibody), cetuximab (epidermal growth factor receptor inhibitor), sorafenib (multikinase inhibitor), and vismodegib (smoothened receptor inhibitor).

RESULTS

No large controlled studies specifically examining the management of DAEs of targeted molecular inhibitors exist, although there are case report-based recommendations and algorithms developed by expert panels to manage these adverse events.

CONCLUSION

Many options for managing the cutaneous side effects of targeted molecular inhibitors are similar to those used in general dermatology practice. When used effectively, drug dosing and patient quality of life may be optimized.

Procyanidin B2 3,3″-di-O-gallate inhibits endothelial cells growth and motility by targeting VEGFR2 and integrin signaling pathways

Targeting angiogenesis, one of the hallmarks of carcinogenesis, using non-toxic phytochemicals has emerged as a translational opportunity for angioprevention and to control advanced stages of malignancy. Herein, we investigated the inhibitory effects and associated mechanism/s of action of Procyanidin B2-3,3″-di- O-gallate (B2G2), a major component of grape seed extract, on human umbilical vein endothelial cells (HUVECs) and human prostate microvascular endothelial cells (HPMECs). Our results showed that B2G2 (10-40 μM) inhibits growth and induces death in both HUVECs and HPMECs. Additional studies revealed that B2G2 causes a G1 arrest in cell cycle progression of HUVECs by down-regulating cyclins (D1 and A), CDKs (Cdk2 and Cdc2) and Cdc25c phosphatase and up-regulating CDK inhibitors (p21 and p27) expression. B2G2 also induced strong apoptotic death in HUVECs through increasing p53, Bax and Smac/Diablo expression while decreasing Bcl-2 and survivin levels. Additionally, B2G2 inhibited the growth factors-induced capillary tube formation in HUVECs and HPMECs. Interestingly, conditioned media (CCM) from prostate cancer (PCA) cells (LNCaP and PC3) grown under normoxic (~21% O2) and hypoxic (1% O2) conditions significantly enhanced the tube formation in HUVECs, which was compromised in presence of conditioned media from B2G2-treated PCA cells. B2G2 also inhibited the motility and invasiveness of both HUVECs and HPMECs. Mechanistic studies showed that B2G2 targets VEGFR2/PI3K/Akt and integrin signaling molecules which are important for endothelial cells survival, proliferation, tube formation and motility. Overall, we report that B2G2 inhibits several attributes of angiogenesis in cell culture; therefore, it warrants further investigation for efficacy for angioprevention and cancer control.

Cutaneous adverse effects of targeted therapies: Part I: Inhibitors of the cellular membrane

There has been a rapid emergence of numerous targeted agents in the oncology community in the last decade. This exciting paradigm shift in drug development lends promise for the future of individualized medicine. Given the pace of development and clinical deployment of targeted agents with novel mechanisms of action, dermatology providers may not be familiar with the full spectrum of associated skin-related toxicities. Cutaneous adverse effects are among the most frequently observed toxicities with many targeted agents, and their intensity can be dose-limiting or lead to therapy discontinuation. In light of the often life-saving nature of emerging oncotherapeutics, it is critical that dermatologists both understand the mechanisms and recognize clinical signs and symptoms of such toxicities in order to provide effective clinical management. Part I of this continuing medical education article will review in detail the potential skin-related adverse sequelae, the frequency of occurrence, and the implications associated with on- and off-target cutaneous toxicities of inhibitors acting at the cell membrane level, chiefly inhibitors of epidermal growth factor receptor, KIT, and BCR-ABL, angiogenesis, and multikinase inhibitors.

Drug safety evaluation of sorafenib for treatment of solid tumors: consequences for the risk assessment and management of cancer patients

INTRODUCTION

Sorafenib is a multi-tyrosine kinase inhibitor (TKI). Considerable clinical experience has been accumulated since its first Phase III clinical trial in metastatic renal cancer patients in 2007. The management of its early acute toxicity in fit patients is well known. The management of prolonged treatment becomes the new challenge.

AREAS COVERED

Using sorafenib as a key word for PubMed search, we review preclinical and clinical data and discuss the pharmacokinetics and pharmacodynamics of sorafenib, its acute and cumulative toxicities and their consequences for patient management.

EXPERT OPINION

The systematic multi-disciplinary risk assessment of cancer patients prior to TKI initiation reduces the risks of acute and late toxicity, especially drug-drug interactions and arterial risks. Sarcopenia is now identified as a major risk of severe toxicity. The very diverse clinical pictures of cumulative toxicity must be known. The monitoring of sorafenib systemic exposure is helpful especially in elderly patients. Moreover, at disease progression, it allows distinguishing between underexposure to sorafenib and truly acquired resistance to the drug. The optimal use of sorafenib should allow improving the reported results of flat-dose. Finally, most of this knowledge could be used for the development and optimal use of the other TKIs.

Fractionation of daily dose increases the predicted risk of severe sorafenib-induced hand-foot syndrome (HFS)

OBJECTIVES

The objective was to quantify the risk dynamics for the sorafenib-induced hand-foot syndrome (HFS) and to explore by simulations the dose-toxicity relationships according to different dosing regimens.

PATIENTS AND METHODS

Eighty-nine patients treated with sorafenib were considered: Treatment duration and regimen, and number and frequency of HFS observations were highly variable. A nonlinear mixed-effect model was built to link sorafenib administrations to the risk of each HFS score, through a latent variable model. Model evaluation was driven by goodness-of-fit and simulation-based diagnostics. Impact of sorafenib regimen on HFS dynamics was evaluated by simulations. A surrogate measure of benefit-to-risk ratio was calculated by using the concept of utility function, accounting for efficacy on tumor growth inhibition and severe HFS risk.

RESULTS AND DISCUSSION

An original pharmacokinetic-pharmacodynamic model for sorafenib-induced HFS, including the kinetics of a latent variable model, relating sorafenib administrations, per se its exposure, to HFS dynamics is proposed. From the model simulations, it appears that the more the daily dose is fractioned, the more the patients are at risk of HFS. Interestingly, the number of daily occasions was found more influential than the dose itself. Taking into account tumor growth inhibition in the utility function, the twice-daily administration schedule is favored for daily doses >600 mg. This approach illustrates how understanding the dynamic relationship between drug administrations and a limiting adverse event may help to control toxicity and adequately adjust treatment modalities.

Cord colitis syndrome: a cause of granulomatous inflammation in the upper and lower gastrointestinal tract

Cord colitis syndrome (CCS) is a recently described diarrheal illness of uncertain pathogenesis that affects recipients of umbilical cord blood transplant and is associated with negative cultures. CCS exhibits a peculiar histopathologic appearance, as it commonly manifests as granulomatous inflammation involving the upper and lower gastrointestinal tract, with features of chronicity in the colon. Importantly, the treatment for CCS differs from that for acute graft-versus-host disease, which is commonly in the clinical differential diagnosis: CCS responds to antibiotic treatment, whereas acute graft-versus-host disease responds to immunosuppression. We describe here the case of a 36-year-old woman with a history of acute myeloid leukemia who developed refractory diarrhea after cord blood transplant. Endoscopic biopsies of the stomach and colon revealed granulomatous inflammation, consisting of scattered ill-defined aggregates of epithelioid histiocytes, with associated mild neutrophilic inflammation and mildly increased epithelial cell apoptosis. In the colon, the granulomatous inflammation was associated with surface epithelial injury (including surface erosions) and contained occasional multinucleated epithelioid giant cells. Paneth cell metaplasia was present in the distal colon, but crypt architecture was preserved, and there was no basal lymphoplasmacytosis. Special stains and immunohistochemical stains for infectious organisms were negative. A diagnosis of CCS was made, and the patient promptly responded to treatment with ciprofloxacin and metronidazole. We present this case to raise awareness among pathologists of this newly described entity, in order to facilitate its timely diagnosis and treatment.

Targeting VEGF signalling via the neuropilin co-receptor

The blockade of tumour vascularisation and angiogenesis continues to be a focus for drug development in oncology and other pathologies. Historically, targeting vascular endothelial growth factor (VEGF) activity and its association with VEGF receptors (VEGFRs) has represented the most promising line of attack. More recently, the recognition that VEGFR co-receptors, neuropilin-1 and -2 (NRP1 and NRP2), are also engaged by specific VEGF isoforms in tandem with the VEGFRs has expanded the landscape for the development of modulators of VEGF-dependent signalling. Here, we review the recent structural characterisation of VEGF interactions with NRP subdomains and the impact this has had on drug development activity in this area.

Triphala and its active constituent chebulinic acid are natural inhibitors of vascular endothelial growth factor-a mediated angiogenesis

Triphala churna (THL) is a combination of three fruits that has been used for many years in India for the treatment of various diseases. There are now reports which indicate that THL can inhibit growth of malignant tumors in animals. However, the mechanisms by which THL mediates its anti-tumor actions are still being explored. Because vascular endothelial growth factor-A (VEGF) induced angiogenesis plays a critical role in the pathogenesis of cancer, we therefore investigated whether tumor inhibitory effects of THL or its active constituents are through suppression of VEGF actions. We herein report that THL and chebulinic (CI) present in THL can significantly and specifically inhibit VEGF induced angiogenesis by suppressing VEGF receptor-2 (VEGFR-2) phosphorylation. These results are of clinical significance as these inexpensive and non-toxic natural products can be used for the prevention and treatment of diseases where VEGF induced angiogenesis has an important role.

Early sorafenib-induced toxicity is associated with drug exposure and UGTIA9 genetic polymorphism in patients with solid tumors: a preliminary study

Background

Identifying predictive biomarkers of drug response is of key importance to improve therapy management and drug selection in cancer therapy. To date, the influence of drug exposure and pharmacogenetic variants on sorafenib-induced toxicity remains poorly documented. The aim of this pharmacokinetic/pharmacodynamic (PK/PD) study was to investigate the relationship between early toxicity and drug exposure or pharmacogenetic variants in unselected adult outpatients treated with single-agent sorafenib for advanced solid tumors.

Methods

Toxicity was recorded in 54 patients on days 15 and 30 after treatment initiation and sorafenib exposure was assessed in 51 patients. The influence of polymorphisms in CYP3A5, UGT1A9, ABCB1 and ABCG2 was examined in relation to sorafenib exposure and toxicity. Clinical characteristics, drug exposure and pharmacogenetic variants were tested univariately for association with toxicities. Candidate variables with p<0.1 were analyzed in a multivariate analysis.

Results

Gender was the sole parameter independently associated with sorafenib exposure (p = 0.0008). Multivariate analysis showed that increased cumulated sorafenib (AUC_cum) was independently associated with any grade ≥3 toxicity (p = 0.037); UGT1A9 polymorphism (rs17868320) with grade ≥2 diarrhea (p = 0.015) and female gender with grade ≥2 hand-foot skin reaction (p = 0.018). Using ROC curve, the threshold AUC_cum value of 3,161 mg/L.h was associated with the highest risk to develop any grade ≥3 toxicity (p = 0.018).

Conclusion

In this preliminary study, increased cumulated drug exposure and UGT1A9 polymorphism (rs17868320) identified patients at high risk for early sorafenib-induced severe toxicity. Further PK/PD studies on larger population are warranted to confirm these preliminary results.

Exogenous albumin inhibits sorafenib-induced cytotoxicity in human cancer cell lines

Sorafenib is an orally administered multikinase inhibitor that exhibits anti-angiogenic and anti-tumor activity. Sorafenib is also known to bind to protein (>99.5%), suggesting protein binding may be involved in sorafenib pharmacokinetic variability. Albumin is a major drug-binding protein. In this study, we examined the effect of albumin on sorafenib-induced cytotoxicity using two in vitro culture cell lines, human hepatoma Huh-7 cells and androgen-independent prostate cancer PC-3 cells. The cells were cultured and incubated, and cytotoxicity was assessed. Results were confirmed by western blotting. The presence of exogenous albumin markedly blocked the sorafenib-induced cytotoxicity in the two cell lines. Albumin concentration, the change of pharmacological signal transduction as Raf-B, vascular endothelial growth factor (VEGF), and phosphorylation of MEK1/2 or ERK1/2 were found to be decreased by sorafenib. Co-incubation of warfarin, a representative coumarin anticoagulant and potent binding activity, with albumin enhanced the cytotoxic effects by sorafenib. These mechanisms depend on the high binding proper ties of sorafenib and exogenous albumin. Furthermore, we investigated the effects of endo genous albumin expression on sorafenib-induced cytotoxicity using the siRNA knockdown system or transfected expression vector assay. However, the cytotoxic effects by sorafenib showed little change either with the knockdown or overexpression of albumin. Our results suggest that particular care should be taken with albuminemia or the combined use of drugs with a high affinity for albumin, such as warfarin, and sorafenib in the treatment of cancer patients. Our findings may be useful to the cancer therapeutic strategy by sorafenib.

Angiopreventive efficacy of pure flavonolignans from milk thistle extract against prostate cancer: targeting VEGF-VEGFR signaling

The role of neo-angiogenesis in prostate cancer (PCA) growth and metastasis is well established, but the development of effective and non-toxic pharmacological inhibitors of angiogenesis remains an unaccomplished goal. In this regard, targeting aberrant angiogenesis through non-toxic phytochemicals could be an attractive angiopreventive strategy against PCA. The rationale of the present study was to compare the anti-angiogenic potential of four pure diastereoisomeric flavonolignans, namely silybin A, silybin B, isosilybin A and isosilybin B, which we established previously as biologically active constituents in Milk Thistle extract. Results showed that oral feeding of these flavonolignans (50 and 100 mg/kg body weight) effectively inhibit the growth of advanced human PCA DU145 xenografts. Immunohistochemical analyses revealed that these flavonolignans inhibit tumor angiogenesis biomarkers (CD31 and nestin) and signaling molecules regulating angiogenesis (VEGF, VEGFR1, VEGFR2, phospho-Akt and HIF-1α) without adversely affecting the vessel-count in normal tissues (liver, lung, and kidney) of tumor bearing mice. These flavonolignans also inhibited the microvessel sprouting from mouse dorsal aortas ex vivo, and the VEGF-induced cell proliferation, capillary-like tube formation and invasiveness of human umbilical vein endothelial cells (HUVEC) in vitro. Further studies in HUVEC showed that these diastereoisomers target cell cycle, apoptosis and VEGF-induced signaling cascade. Three dimensional growth assay as well as co-culture invasion and in vitro angiogenesis studies (with HUVEC and DU145 cells) suggested the differential effectiveness of the diastereoisomers toward PCA and endothelial cells. Overall, these studies elucidated the comparative anti-angiogenic efficacy of pure flavonolignans from Milk Thistle and suggest their usefulness in PCA angioprevention.

Inhibition of the Ras/Raf/MEK/ERK and RET kinase pathways with the combination of the multikinase inhibitor sorafenib and the farnesyltransferase inhibitor tipifarnib in medullary and differentiated thyroid malignancies

PURPOSE

Ras/Raf/MAPK kinase/ERK and rearranged in transformation (RET) kinase pathways are important in thyroid cancer. We tested sorafenib, a B-Raf, RET, and vascular endothelial growth factor receptor kinase inhibitor, combined with tipifarnib, a farnesyltransferase inhibitor that inactivates Ras and other farnesylated proteins.

PATIENTS AND METHODS

We treated 35 patients with differentiated thyroid cancer (DTC) and medullary thyroid cancer (MTC) in a phase I trial. Sorafenib and tipifarnib were given for 21 d with 7 d rest in each 28-d cycle.

RESULTS

We enrolled 22 patients with metastatic DTC (16 papillary, five follicular, and one poorly differentiated) and 13 patients with MTC, of whom 15 with DTC and 10 with MTC reached first restaging. When tissue was available, eight of 15 DTC patients (53%) had B-Raf mutations; eight of 13 MTC (61.5%) patients had RET mutations. MTC partial response rate was 38% (five of 13) (duration = 9+, 12, 13, 16+, and 34+ months), stable disease of at least 6 months was 31% (four of 13). The DTC partial response rate was 4.5% (one of 22), and stable disease of at least 6 months was 36% (eight of 22). Median progression-free survival for all 35 patients was 18 months (95% confidence interval, 14.6 to not reached months). Median overall survival has not been reached, with a median follow-up of 24 months with 80% overall survival. Grade 1-2 toxicities were mainly rash, fatigue, and diarrhea. The most common grade 3-4 toxicities were rash, rise in amylase/lipase, and fatigue.

CONCLUSIONS

Inhibiting the Ras/Raf/MAPK kinase/ERK and RET kinase pathways with sorafenib and tipifarnib is well tolerated and active against thyroid cancer.

Pharmacokinetic interaction involving sorafenib and the calcium-channel blocker felodipine in a patient with hepatocellular carcinoma

Sorafenib, an orally active multi-kinase inhibitor approved for the treatment of hepatocellular carcinoma (HCC), is primarily metabolized both via cytochrome P450 3A4 isoform (CYP3A4) and UGT1A9. Due to the contribution of these two biotransformation pathways, sorafenib is considered to be less susceptible than other agents to CYP3A4 drug-drug interactions. This report discusses a clinically relevant pharmacokinetic CYP3A4 drug-drug interaction between sorafenib and felodipine in an 80-year-old Caucasian patient with HCC. On day 15, after the introduction of sorafenib (400 mg bid), sorafenib plasma concentration was at 3.6 mg/L. Felodipine (5 mg bid), an anti-hypertensive agent that is exclusively CYP3A4 substrate, was then introduced due to grade 2 sorafenib-related hypertension. On day 30, hypertension was well controlled. However, sorafenib plasma concentration was 3-fold greater (11.4 mg/L) and the patient experienced grade-3 anorexia. Since neither diarrhea nor cutaneous side effects were noticed at this time, sorafenib treatment was continued at the same daily dosage. On day 45, sorafenib plasma concentration was stable (10.8 mg/L) before declining on days 60 and 75 (7.0 mg/L and 7.4 mg/L, respectively), which was probably related to an occurrence of grade-2 diarrhea. This observation suggests a pharmacokinetic interaction involving CYP3A4 inhibition by felodipine. According to the Drug Interaction Probability Scale, this interaction was possible. Since hypertension is a common toxicity of sorafenib, clinicians should be aware of this possible interaction. The clinical relevance of pharmacokinetic interactions involving CYP3A4 inhibition in HCC patients receiving sorafenib is analyzed in this case report.