Enhanced Bioavailability and Reduced Variability of Dasatinib and Sorafenib with a Novel Amorphous Solid Dispersion Technology Platform

Despite clinical advances with protein kinase inhibitors (PKIs), oral administration of many PKIs is associated with highly variable plasma exposure and a narrow therapeutic window. We developed a novel hybrid nanoparticle-amorphous solid dispersion (ASD) technology platform consisting of an amorphous PKI embedded in a polymer matrix. The technology was used to manufacture immediate-release formulations of 2 tyrosine kinase inhibitors (TKIs), dasatinib and sorafenib. Our primary objective was to improve the absorption properties and reduce the pharmacokinetic (PK) variability of each TKI. The PKs of XS004 (dasatinib-ASD, 100 mg tablet) and XS005 (sorafenib-ASD, 2 × 50 mg capsules) were compared with their crystalline formulated reference drugs (140 mg of dasatinib-reference and 200 mg of sorafenib-reference). The in vitro biopharmaceutics of dasatinib-ASD and XS005-granulate showed sustained increased solubility in the pH range 1.2-8.0 compared to their crystalline references. In vivo, XS004 was bioequivalent at a 30% lower dose and showed increased absorption and bioavailability, with 2.1-4.8 times lower intra- and intersubject variability compared to the reference. XS005 had an increased absorption and bioavailability of 45% and 2.2-2.8 times lower variability, respectively, but it was not bioequivalent at the investigated dose level. Taken together, the formulation platform is suited to generate improved PKI formulations with consistent bioavailability and a reduced pH-dependent absorption process.

Mechanism Underlying Conflicting Drug-Drug Interaction Between Aprepitant and Voriconazole via Cytochrome P450 3A4-Mediated Metabolism

Background

Voriconazole is an antifungal drug for which therapeutic monitoring is recommended to prevent side effects. Temporary administration of the antiemetic drug fosaprepitant remarkably decreases the plasma concentration of voriconazole from the therapeutic range. The ratio of the major metabolite voriconazole N-oxide to voriconazole exceeded that at any other time for a patient who started chemotherapy during voriconazole therapy. We attributed this unpredictable result to cytochrome P450 3A4 induced by aprepitant that was converted from fosaprepitant in vivo.

Methods

Concentrations of voriconazole and voriconazole N-oxide were measured using liquid chromatography-mass spectrometry/mass spectrometry in primary human hepatocytes after incubation with aprepitant. Aprepitant suppressed voriconazole N-oxide formation within 24 h, followed by a continuous increase. Levels of drug-metabolizing cytochrome P450 mRNA were measured using real-time PCR in primary human hepatocytes incubated with aprepitant.

Results

Cytochrome P450 3A4 and 2C9 mRNA levels increased ~4- and 2-fold, respectively, over time. Cytochrome P450 3A4 induction was confirmed using reporter assays. We also assessed L-755446, a major metabolite of aprepitant that lacks a triazole ring. Both compounds dose-dependently increased reporter activity; however, induction by L-755446 was stronger than that by aprepitant.

Conclusion

These results indicate that aprepitant initially inhibited voriconazole metabolism via its triazole ring and increased cytochrome P450 3A4 induction following L-755446 formation. The decrease in plasma voriconazole concentration 7 days after fosaprepitant administration was mainly attributed to cytochrome P450 3A4 induction by L-755446.

Therapeutic Drug Monitoring of Kinase Inhibitors in Oncology

Although kinase inhibitors (KI) frequently portray large interpatient variability, a 'one size fits all' regimen is still often used. In the meantime, relationships between exposure-response and exposure-toxicity have been established for several KIs, so this regimen could lead to unnecessary toxicity and suboptimal efficacy. Dose adjustments based on measured systemic pharmacokinetic levels-i.e., therapeutic drug monitoring (TDM)-could therefore improve treatment efficacy and reduce the incidence of toxicities. Therefore, the aim of this comprehensive review is to give an overview of the available evidence for TDM for the 77 FDA/EMA kinase inhibitors currently approved (as of July 1st, 2023) used in hematology and oncology. We elaborate on exposure-response and exposure-toxicity relationships for these kinase inhibitors and provide practical recommendations for TDM and discuss corresponding pharmacokinetic targets when possible.

Feasibility of therapeutic drug monitoring of sorafenib in patients with liver or thyroid cancer

INTRODUCTION

Sorafenib is a tyrosine-kinase inhibitor approved for the treatment of renal cell carcinoma, hepatocellular carcinoma, thyroid carcinoma, and desmoid fibromatosis. As high inter-individual variability exists in exposure, there is a scientific rationale to pursue therapeutic drug monitoring (TDM). We investigated the feasibility of TDM in patients on sorafenib and tried to identify sub-groups in whom pharmacokinetically (PK) guided-dosing might be of added value.

METHODS

We included patients who started on sorafenib (between October 2017 and June 2020) at the recommended dose of 400 mg BID or with a step-up dosing schedule. Plasma trough levels (C_trough) were measured at pre-specified time-points. Increasing the dose was advised if C_trough was below the target of 3750 ng/mL and toxicity was manageable.

RESULTS

A total of 150 samples from 36 patients were collected. Thirty patients (83 %) had a C_trough below the prespecified target concentration at a certain time point during treatment. Toxicity from sorafenib hampered dosing according to target C_trough in almost half of the patients. In 11 patients, dosing was adjusted based on C_trough. In three patients, this resulted in an adequate C_trough without additional toxicity four weeks after the dose increase. In the remaining eight patients, dose adjustment based on C_trough did not result in a C_trough above the target or caused excessive toxicity.

CONCLUSIONS

TDM for sorafenib is not of added value in daily clinical practice. In most cases, toxicity restricts the possibility of dose escalations.

Phase I Study Evaluating Dose De-escalation of Sorafenib with Metformin and Atorvastatin in Hepatocellular Carcinoma (SMASH)

BACKGROUND

This phase I dose de-escalation study aimed to assess the tolerability, safety, pharmacokinetics (PK), and efficacy of sequentially decreasing doses of sorafenib in combination (SAM) with atorvastatin (A, 10 mg) and metformin (M, 500 mg BD) in patients with advanced hepatocellular carcinoma (HCC).

METHODS

Patients were enrolled in 1 of 4 sequential cohorts (10 patients each) of sorafenib doses (800 mg, 600 mg. 400 mg, and 200 mg) with A and M. Progression from one level to the next was based on prespecified minimum disease stabilization (at least 4/10) and upper limits of specific grade 3-5 treatment-related adverse events (TRAE).

RESULTS

The study was able to progress through all 4 dosing levels of sorafenib by the accrual of 40 patients. Thirty-eight (95%) patients had either main portal vein thrombosis or/and extra-hepatic disease. The most common grade 3-5 TRAEs were hand-foot-syndrome (grade 2 and grade 3) in 3 (8%) and transaminitis in 2 (5%) patients, respectively. The plasma concentrations of sorafenib peaked at 600 mg dose, and the concentration threshold of 2400 ng/mL was associated with higher odds of achieving time to exposure (TTE) concentrations >75% centile (odds ratio [OR] = 10.0 [1.67-44.93]; P = .01). The median overall survival for patients without early hepatic decompensation (n = 31) was 8.9 months (95% confidence interval [CI]: 3.2-14.5 months).

CONCLUSION

The SAM combination in HCC patients with predominantly unfavorable baseline disease characteristics showed a marked reduction in sorafenib-related side effects. Studies using sorafenib 600 mg per day in this combination along with sorafenib drug level monitoring can be evaluated in further trials.(Trial ID: CTRI/2018/07/014865).

Evaluating the utility of therapeutic drug monitoring in the clinical use of small molecule kinase inhibitors: a review of the literature

Introduction: Orally administered small molecule kinase inhibitors (KI) are a key class of targeted anti-cancer medicines that have contributed substantially to improved survival outcomes in patients with advanced disease. Since the introduction of KIs in 2001, there has been a building body of evidence that the benefit derived from these drugs may be further enhanced by individualizing dosing on the basis of concentration.Areas covered: This review considers the rationale for individualized KI dosing and the requirements for robust therapeutic drug monitoring (TDM). Current evidence supporting TDM-guided KI dosing is presented and critically evaluated, and finally potential approaches to address translational challenges for TDM-guided KI dosing and alternate approaches to support individualization of KI dosing are discussed.Expert opinion: Intuitively, the individualization of KI dosing through an approach such as TDM-guided dosing has great potential to enhance the effectiveness and tolerability of these drugs. However, based on current literature evidence it is unrealistic to propose that TDM-guided KI dosing should be routinely implemented into clinical practice.

Therapeutic drug monitoring of oral targeted antineoplastic drugs

PURPOSE

This review provides an overview of the current challenges in oral targeted antineoplastic drug (OAD) dosing and outlines the unexploited value of therapeutic drug monitoring (TDM). Factors influencing the pharmacokinetic exposure in OAD therapy are depicted together with an overview of different TDM approaches. Finally, current evidence for TDM for all approved OADs is reviewed.

METHODS

A comprehensive literature search (covering literature published until April 2020), including primary and secondary scientific literature on pharmacokinetics and dose individualisation strategies for OADs, together with US FDA Clinical Pharmacology and Biopharmaceutics Reviews and the Committee for Medicinal Products for Human Use European Public Assessment Reports was conducted.

RESULTS

OADs are highly potent drugs, which have substantially changed treatment options for cancer patients. Nevertheless, high pharmacokinetic variability and low treatment adherence are risk factors for treatment failure. TDM is a powerful tool to individualise drug dosing, ensure drug concentrations within the therapeutic window and increase treatment success rates. After reviewing the literature for 71 approved OADs, we show that exposure-response and/or exposure-toxicity relationships have been established for the majority. Moreover, TDM has been proven to be feasible for individualised dosing of abiraterone, everolimus, imatinib, pazopanib, sunitinib and tamoxifen in prospective studies. There is a lack of experience in how to best implement TDM as part of clinical routine in OAD cancer therapy.

CONCLUSION

Sub-therapeutic concentrations and severe adverse events are current challenges in OAD treatment, which can both be addressed by the application of TDM-guided dosing, ensuring concentrations within the therapeutic window.

Development and clinical validation of a simple and fast UPLC-ESI-MS/MS method for simultaneous quantification of nine kinase inhibitors and two antiandrogen drugs in human plasma: Interest for their therapeutic drug monitoring

Kinase inhibitors (KIs) and antiandrogen drugs (AAs) are oral anticancer drugs with narrow therapeutic index that exhibit high inter- and intra-individual variability. We describe here a UPLC-MS/MS method for the simultaneous quantification of nine KIs: cobimetinib, dasatinib, ibrutinib, imatinib, nilotinib, palbociclib, ruxolitinib, sorafenib and vemurafenib; two active metabolites of them: N-desmethyl imatinib, N-oxide sorafenib; and two AAs: abiraterone and enzalutamide; with short pre-treatment and run time in order to be easily used in clinical practice for their therapeutic drug monitoring (TDM) and facilitating pharmacokinetics and pharmacokinetics/pharmacodynamics studies. Plasma samples were prepared by a single-step protein precipitation. Analytes were separated on a Waters Acquity UPLC® T3 HSS C18 column by non-linear gradient elution; with subsequent detection by Xevo® TQD triple quadrupole tandem mass spectrometer in a positive ionization mode. Analysis time was 2.8 min per run, and all analytes eluted within 1.46-1.97 minutes. The analytical performance of the method in terms of specificity, sensitivity, linearity, precision, accuracy, matrix effect, extraction recovery, limit of quantification, dilution integrity and stability of analytes under different conditions met all criteria for a bioanalytical method for the quantification of drugs. The calibration curves were linear over the range of 1-500 ng/mL for abiraterone, dasatinib and ibrutinib; 5-500 ng/mL for cobimetinib and palbociclib; 10-5,000 ng/mL for imatinib, N-desmethyl imatinib, nilotinib, sorafenib, N-oxide sorafenib and ruxolitinib; 100-50,000 ng/mL for enzalutamide and 100-100,000 ng/mL for vemurafenib with coefficient of correlation above 0.995 for all analytes. This novel method was successfully applied to TDM in clinical practice.

Sorafenib reduces steatosis-induced fibrogenesis in a human 3D co-culture model of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) affects around 25% of the worldwide population. Non-alcoholic steatohepatitis (NASH), the more progressive variant of NAFLD, is characterized by steatosis, cellular ballooning, lobular inflammation, and may culminate on hepatic stellate cell (HSC) activation, thus increasing the risk for fibrosis, cirrhosis, and HCC development. Conversely, the antifibrotic effects of sorafenib, an FDA-approved drug for HCC treatment, have been demonstrated in 2D cell cultures and animal models, but its mechanisms in a NAFLD-related microenvironment in vitro requires further investigation. Thus, a human 3D co-culture model of fatty hepatocytes and HSC was established by culturing hepatoma C3A cells, pre-treated with 1.32 mM oleic acid, with HSC LX-2 cells. The fatty C3A/LX-2 spheroids showed morphological and molecular hallmarks of altered lipid metabolism and steatosis-induced fibrogenesis, similarly to the human disease. Sorafenib (15 μM) for 72 hours reduced fatty spheroid viability, and upregulated the expression of lipid oxidation- and hydrolysis-related genes, CPT1 and LIPC, respectively. Sorafenib also inhibited steatosis-induced fibrogenesis by downregulating COL1A1, TGFB1, PDGF, and TIMP1 and by decreasing protein levels of IL-6, TGF-β1, and TNF-α in fatty spheroids. The demonstration of the antifibrotic properties of sorafenib on steatosis-induced fibrogenesis in a 3D in vitro model of NAFLD supports its clinical use as a therapeutic agent for the treatment of NAFLD/NASH patients.

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 value of sorafenib trough levels in patients with advanced hepatocellular carcinoma - a substudy of the SORAMIC trial

Background: Sorafenib for advanced hepatocellular carcinoma (HCC) is dose adjusted by toxicity. Preliminary studies have suggested an association between plasma concentrations of sorafenib and its main metabolite (M2) and clinical outcomes. This study aimed to validate these findings and establish target values for sorafenib trough concentrations.Methods: Patients with advanced HCC were prospectively recruited within a multicenter phase II study (SORAMIC). Patients with blood samples available at trough level were included for this pharmacokinetic (PK) substudy. Trough plasma concentrations of sorafenib and its main metabolite (M2) were associated with sorafenib-related toxicity and overall survival (OS).Results: Seventy-four patients were included with a median OS of 19.7 months (95% CI 16.1-23.3). Patients received sorafenib for a median of 51 weeks (IQR 27-62) and blood samples were drawn after a median of 25 weeks (IQR 10-42). Patients had a median trough concentration of 3217 ng/ml (IQR 2166-4526) and 360 ng/ml (IQR 190-593) with coefficients of variation of 65% and 146% for sorafenib and M2, respectively. Patients who experienced severe sorafenib-related toxicity received a lower average daily dose (551 vs 730 mg/day, p = .003), but showed no significant differences in sorafenib (3298 vs 2915 ng/ml, p = .442) or M2 trough levels (428 vs 283 ng/ml, p = .159). Trough levels of sorafenib or M2 showed no significant association with OS.Conclusions: In patients with advanced HCC treated with sorafenib, the administered dose, trough levels of sorafenib or M2, and clinical outcomes were poorly correlated. Toxicity-adjusted dosing remains the standard for sorafenib treatment.

In vivo assessment of potential for UGT-inhibition-based drug-drug interaction between sorafenib and tapentadol

Sorafenib (SR) is one of the most potent UGT (1A1, 1A9) inhibitors (in in vitro tests). The inhibition of UGT1A1 may cause hyperbilirubinaemia, whereas the inhibition of UGT1A9 and 1A1 may result in drug-drug interactions (DDIs). Tapentadol (TAP) is a synthetic μ-opioid agonist and is used to treat moderate to severe acute pain. Tapentadol is highly glucuronidated by the UGT1A9 and UGT2B7 isoenzymes. The aim of the study was to assess the DDI between SR and TAP. Wistar rats were divided into three groups, with eight animals in each. The rats were orally treated with SR (100 mg/kg) or TAP (4.64 mg/kg) or in combination with 100 mg/kg SOR and 4.64 TAP mg/kg. The concentrations of SR and sorafenib N-oxide, TAP and tapentadol glucuronide were respectively measured by means of high-performance liquid chromatography (HPLC) with ultraviolet detection and by means of ultra-performance liquid chromatography-tandem mass spectrometry. The co-administration of TAP with SR caused TAP maximum plasma concentration (C_max) to increase 5.3-fold whereas its area under the plasma concentration-time curve (AUC_0-∞) increased 1.5-fold. The tapentadol glucuronide C_max increased 5.3-fold and whereas its AUC_0-∞ increased 2.0-fold. The tapentadol glucuronide/TAP AUC_0-∞ ratio increased 1.4-fold (p = 0.0118). TAP also increased SR C_max 1.9-fold, whereas its AUC_0-∞ increased 1.3-fold. The sorafenib N-oxide C_max increased 1.9-fold whereas its AUC_0-∞ increased 1.3-fold. The sorafenib N-oxide/SR AUC_0-t ratio increased 1.4-fold (p = 0.0127). The results show that the co-administration of sorafenib and tapentadol increases the exposure to both drugs and changes their metabolism. In consequence, the pharmacological effect may be intensified, but the toxicity may increases, too.

Clinical Pharmacokinetics and Pharmacodynamics of Transarterial Chemoembolization and Targeted Therapies in Hepatocellular Carcinoma

The management of hepatocellular carcinoma (HCC) is based on a multidisciplinary decision tree. Treatment includes loco-regional therapy, mainly transarterial chemoembolization, for intermediate-stage HCC and systemic therapy with oral tyrosine kinase inhibitors (TKIs) for advanced HCC. Transarterial chemoembolization involves hepatic intra-arterial infusion with either conventional procedure or drug-eluting-beads. The aim of the loco-regional procedure is to deliver treatment as close as possible to the tumor both to embolize the tumor area and to enhance efficacy and minimize systemic toxicity of the anticancer drug. Pharmacokinetic studies applied to transarterial chemoembolization are rare and pharmacodynamic studies even rarer. However, all available studies lead to the same conclusions: use of the transarterial route lowers systemic exposure to the cytotoxic drug and leads to much higher tumor drug concentrations than does a similar dose via the intravenous route. However, reproducibility of the procedure remains a major problem, and no consensus exists regarding the choice of anticancer drug and its dosage. Systemic therapy with TKIs is based on sorafenib and lenvatinib as first-line treatment and regorafenib and cabozantinib as second-line treatment. Clinical use of TKIs is challenging because of their complex pharmacokinetics, with high liver metabolism yielding both active metabolites and their common toxicities. Changes in liver function over time with the progression of HCC adds further complexity to the use of TKIs. The challenges posed by TKIs and the HCC disease process means monitoring of TKIs is required to improve clinical management. To date, only partial data supporting sorafenib monitoring is available. Results from further pharmacokinetic/pharmacodynamic studies of these four TKIs are eagerly awaited and are expected to permit such monitoring and the development of consensus guidelines.

Sorafenib Dose Recommendation in Acute Myeloid Leukemia Based on Exposure-FLT3 Relationship

Sorafenib administered at the approved dose continuously is not tolerated long-term in patients with acute myeloid leukemia (AML). The purpose of this study was to optimize the dosing regimen by characterizing the sorafenib exposure-response relationship in patients with AML. A one-compartment model with a transit absorption compartment and enterohepatic recirculation described the exposure. The relationship between sorafenib exposure and target modulation of kinase targets (FMS-like tyrosine kinase 3 (FLT3)-ITD and extracellular signal-regulated kinase (ERK)) were described by an inhibitory maximum effect (Emax ) model. Sorafenib could inhibit FLT3-ITD activity by 100% with an IC50 of 69.3 ng/mL and ERK activity by 84% with an IC50 of 85.7 ng/mL (both adjusted for metabolite potency). Different dosing regimens utilizing 200 or 400 mg at varying frequencies were simulated based on the exposure-response relationship. Simulations demonstrate that a 200 mg twice daily (b.i.d.) dosing regimen showed similar FLT3-ITD and ERK inhibitory activity compared with 400 mg b.i.d. and is recommended in further clinical trials in patients with AML.

The effects of triptolide on the pharmacokinetics of sorafenib in rats and its potential mechanism

CONTEXT

Combining sorafenib with triptolide could inhibit tumour growth with greater efficacy than single-agent treatment. However, their herb-drug interaction remains unknown.

OBJECTIVE

This study investigates the herb-drug interaction between triptolide and sorafenib.

MATERIALS AND METHODS

The effects of triptolide (10 mg/kg) on the pharmacokinetics of different doses of sorafenib (20, 50 and 100 mg/kg) in rats, and blood samples were collected within 48 h and evaluated using LC-MS/MS. The effects of triptolide on the absorption and metabolism of sorafenib were also investigated using Caco-2 cell monolayer model and rat liver microsome incubation systems.

RESULTS

The results showed that the C_max (low dose: 72.38 ± 8.76 versus 49.15 ± 5.46 ng/mL; medium dose: 178.65 ± 21.05 versus 109.31 ± 14.17 ng/mL; high dose: 332.81 ± 29.38 versus 230.86 ± 9.68 ng/mL) of sorafenib at different doses increased significantly with the pretreatment of triptolide, and while the oral clearance rate of sorafenib decreased. The t_1/2 of sorafenib increased significant (p < 0.05) from 9.02 ± 1.16 to 12.17 ± 2.95 h at low dose with the pretreatment of triptolide. Triptolide has little effect on the absorption of sorafenib in Caco-2 cell transwell model. However, triptolide could significantly decrease the intrinsic clearance rate of sorafenib from 51.7 ± 6.37 to 32.4 ± 4.43 μL/min/mg protein in rat liver microsomes.

DISCUSSION AND CONCLUSIONS

These results indicated that triptolide could change the pharmacokinetic profiles of sorafenib in rats; these effects might be exerted via decreasing the intrinsic clearance rate of sorafenib in rat liver.

Practical Recommendations for Therapeutic Drug Monitoring of Kinase Inhibitors in Oncology

Despite the fact that pharmacokinetic exposure of kinase inhibitors (KIs) is highly variable and clear relationships exist between exposure and treatment outcomes, fixed dosing is still standard practice. This review aims to summarize the available clinical pharmacokinetic and pharmacodynamic data into practical guidelines for individualized dosing of KIs through therapeutic drug monitoring (TDM). Additionally, we provide an overview of prospective TDM trials and discuss the future steps needed for further implementation of TDM of KIs.

Influence of OATP1B1 Function on the Disposition of Sorafenib-β-D-Glucuronide

The oral multikinase inhibitor sorafenib undergoes extensive UGT1A9-mediated formation of sorafenib-β-D-glucuronide (SG). Using transporter-deficient mouse models, it was previously established that SG can be extruded into bile by ABCC2 or follow a liver-to-blood shuttling loop via ABCC3-mediated efflux into the systemic circulation, and subsequent uptake in neighboring hepatocytes by OATP1B-type transporters. Here we evaluated the possibility that this unusual process, called hepatocyte hopping, is also operational in humans and can be modulated through pharmacological inhibition. We found that SG transport by OATP1B1 or murine Oatp1b2 was effectively inhibited by rifampin, and that this agent can significantly increase plasma levels of SG in wildtype mice, but not in Oatp1b2-deficient animals. In human subjects receiving sorafenib, rifampin acutely increased the systemic exposure to SG. Our study emphasizes the need to consider hepatic handling of xenobiotic glucuronides in the design of drug-drug interaction studies of agents that undergo extensive phase II conjugation.

Polymorphisms in SLCO1B1 and UGT1A1 are associated with sorafenib-induced toxicity

AIM

Sorafenib-treated patients display a substantial variation in the incidence of toxicity. We aimed to investigate the association of genetic polymorphisms with observed toxicity on sorafenib.

PATIENTS & METHODS

We genotyped 114 patients that were treated with sorafenib at the Erasmus MC Cancer Institute, the Netherlands, for SLCO1B1, SLCO1B3, ABCC2, ABCG2, UGT1A1 and UGT1A9.

RESULTS

The UGT1A1 (rs8175347) polymorphism was associated with hyperbilirubinemia and treatment interruption. Polymorphisms in SLCO1B1 (rs2306283, rs4149056) were associated with diarrhea and thrombocytopenia, respectively. None of the investigated polymorphisms was associated with overall or progression-free survival in hepatocellular cancer patients.

CONCLUSION

Polymorphisms in SLCO1B1 and UGT1A1 are associated with several different sorafenib side effects.