Results from an in vitro and a clinical/pharmacological phase I study with the combination irinotecan and sorafenib

Drug-drug interactions that alter the exposure of glucuronidated drugs: Scope, UDP-glucuronosyltransferase (UGT) enzyme selectivity, mechanisms (inhibition and induction), and clinical significance

Drug-drug interactions (DDIs) arising from the perturbation of drug metabolising enzyme activities represent both a clinical problem and a potential economic loss for the pharmaceutical industry. DDIs involving glucuronidated drugs have historically attracted little attention and there is a perception that interactions are of minor clinical relevance. This review critically examines the scope and aetiology of DDIs that result in altered exposure of glucuronidated drugs. Interaction mechanisms, namely inhibition and induction of UDP-glucuronosyltransferase (UGT) enzymes and the potential interplay with drug transporters, are reviewed in detail, as is the clinical significance of known DDIs. Altered victim drug exposure arising from modulation of UGT enzyme activities is relatively common and, notably, the incidence and importance of UGT induction as a DDI mechanism is greater than generally believed. Numerous DDIs are clinically relevant, resulting in either loss of efficacy or an increased risk of adverse effects, necessitating dose individualisation. Several generalisations relating to the likelihood of DDIs can be drawn from the known substrate and inhibitor selectivities of UGT enzymes, highlighting the importance of comprehensive reaction phenotyping studies at an early stage of drug development. Further, rigorous assessment of the DDI liability of new chemical entities that undergo glucuronidation to a significant extent has been recommended recently by regulatory guidance. Although evidence-based approaches exist for the in vitro characterisation of UGT enzyme inhibition and induction, the availability of drugs considered appropriate for use as 'probe' substrates in clinical DDI studies is limited and this should be research priority.

Angiogenesis inhibitors for the treatment of epithelial ovarian cancer

BACKGROUND

Many women, and other females, with epithelial ovarian cancer (EOC) develop resistance to conventional chemotherapy drugs. Drugs that inhibit angiogenesis (development of new blood vessels), essential for tumour growth, control cancer growth by denying blood supply to tumour nodules.

OBJECTIVES

To compare the effectiveness and toxicities of angiogenesis inhibitors for treatment of epithelial ovarian cancer (EOC).

SEARCH METHODS

We identified randomised controlled trials (RCTs) by searching CENTRAL, MEDLINE and Embase (from 1990 to 30 September 2022). We searched clinical trials registers and contacted investigators of completed and ongoing trials for further information.

SELECTION CRITERIA

RCTs comparing angiogenesis inhibitors with standard chemotherapy, other types of anti-cancer treatment, other angiogenesis inhibitors with or without other treatments, or placebo/no treatment in a maintenance setting, in women with EOC.  DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. Our outcomes were overall survival (OS), progression-free survival (PFS), quality of life (QoL), adverse events (grade 3 and above) and hypertension (grade 2 and above).

MAIN RESULTS

We identified 50 studies (14,836 participants) for inclusion (including five studies from the previous version of this review): 13 solely in females with newly-diagnosed EOC and 37 in females with recurrent EOC (nine studies in platinum-sensitive EOC; 19 in platinum-resistant EOC; nine with studies with mixed or unclear platinum sensitivity). The main results are presented below.  Newly-diagnosed EOC Bevacizumab, a monoclonal antibody that binds vascular endothelial growth factor (VEGF), given with chemotherapy and continued as maintenance, likely results in little to no difference in OS compared to chemotherapy alone (hazard ratio (HR) 0.97, 95% confidence interval (CI) 0.88 to 1.07; 2 studies, 2776 participants; moderate-certainty evidence). Evidence is very uncertain for PFS (HR 0.82, 95% CI 0.64 to 1.05; 2 studies, 2746 participants; very low-certainty evidence), although the combination results in a slight reduction in global QoL (mean difference (MD) -6.4, 95% CI -8.86 to -3.94; 1 study, 890 participants; high-certainty evidence). The combination likely increases any adverse event (grade ≥ 3) (risk ratio (RR) 1.16, 95% CI 1.07 to 1.26; 1 study, 1485 participants; moderate-certainty evidence) and may result in a large increase in hypertension (grade ≥ 2) (RR 4.27, 95% CI 3.25 to 5.60; 2 studies, 2707 participants; low-certainty evidence). Tyrosine kinase inhibitors (TKIs) to block VEGF receptors (VEGF-R), given with chemotherapy and continued as maintenance, likely result in little to no difference in OS (HR 0.99, 95% CI 0.84 to 1.17; 2 studies, 1451 participants; moderate-certainty evidence) and likely increase PFS slightly (HR 0.88, 95% CI 0.77 to 1.00; 2 studies, 2466 participants; moderate-certainty evidence). The combination likely reduces QoL slightly (MD -1.86, 95% CI -3.46 to -0.26; 1 study, 1340 participants; moderate-certainty evidence), but it increases any adverse event (grade ≥ 3) slightly (RR 1.31, 95% CI 1.11 to 1.55; 1 study, 188 participants; moderate-certainty evidence) and may result in a large increase in hypertension (grade ≥ 3) (RR 6.49, 95% CI 2.02 to 20.87; 1 study, 1352 participants; low-certainty evidence).  Recurrent EOC (platinum-sensitive) Moderate-certainty evidence from three studies (with 1564 participants) indicates that bevacizumab with chemotherapy, and continued as maintenance, likely results in little to no difference in OS (HR 0.90, 95% CI 0.79 to 1.02), but likely improves PFS (HR 0.56, 95% CI 0.50 to 0.63) compared to chemotherapy alone. The combination may result in little to no difference in QoL (MD 0.8, 95% CI -2.11 to 3.71; 1 study, 486 participants; low-certainty evidence), but it increases the rate of any adverse event (grade ≥ 3) slightly (RR 1.11, 1.07 to 1.16; 3 studies, 1538 participants; high-certainty evidence). Hypertension (grade ≥ 3) was more common in arms with bevacizumab (RR 5.82, 95% CI 3.84 to 8.83; 3 studies, 1538 participants).  TKIs with chemotherapy may result in little to no difference in OS (HR 0.86, 95% CI 0.67 to 1.11; 1 study, 282 participants; low-certainty evidence), likely increase PFS (HR 0.56, 95% CI 0.44 to 0.72; 1 study, 282 participants; moderate-certainty evidence), and may have little to no effect on QoL (MD 6.1, 95% CI -0.96 to 13.16; 1 study, 146 participants; low-certainty evidence). Hypertension (grade ≥ 3) was more common with TKIs (RR 3.32, 95% CI 1.21 to 9.10). Recurrent EOC (platinum-resistant) Bevacizumab with chemotherapy and continued as maintenance increases OS (HR 0.73, 95% CI 0.61 to 0.88; 5 studies, 778 participants; high-certainty evidence) and likely results in a large increase in PFS (HR 0.49, 95% CI 0.42 to 0.58; 5 studies, 778 participants; moderate-certainty evidence). The combination may result in a large increase in hypertension (grade ≥ 2) (RR 3.11, 95% CI 1.83 to 5.27; 2 studies, 436 participants; low-certainty evidence). The rate of bowel fistula/perforation (grade ≥ 2) may be slightly higher with bevacizumab (RR 6.89, 95% CI 0.86 to 55.09; 2 studies, 436 participants). Evidence from eight studies suggest TKIs with chemotherapy likely result in little to no difference in OS (HR 0.85, 95% CI 0.68 to 1.08; 940 participants; moderate-certainty evidence), with low-certainty evidence that it may increase PFS (HR 0.70, 95% CI 0.55 to 0.89; 940 participants), and may result in little to no meaningful difference in QoL (MD ranged from -0.19 at 6 weeks to -3.40 at 4 months). The combination increases any adverse event (grade ≥ 3) slightly (RR 1.23, 95% CI 1.02 to 1.49; 3 studies, 402 participants; high-certainty evidence). The effect on bowel fistula/perforation rates is uncertain (RR 2.74, 95% CI 0.77 to 9.75; 5 studies, 557 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS

Bevacizumab likely improves both OS and PFS in platinum-resistant relapsed EOC. In platinum-sensitive relapsed disease, bevacizumab and TKIs probably improve PFS, but may or may not improve OS. The results for TKIs in platinum-resistant relapsed EOC are similar. The effects on OS or PFS in newly-diagnosed EOC are less certain, with a decrease in QoL and increase in adverse events. Overall adverse events and QoL data were more variably reported than were PFS data. There appears to be a role for anti-angiogenesis treatment, but given the additional treatment burden and economic costs of maintenance treatments, benefits and risks of anti-angiogenesis treatments should be carefully considered.

Development of UPLC-MS/MS Method to Study the Pharmacokinetic Interaction between Sorafenib and Dapagliflozin in Rats

Sorafenib (SOR), an inhibitor of multiple kinases, is a classic targeted drug for advanced hepatocellular carcinoma (HCC) which often coexists with type 2 diabetes mellitus (T2DM). Dapagliflozin (DAPA), a sodium–glucose cotransporter-2 inhibitor (SGLT2i), is widely used in patients with T2DM. Notably, co-administration of SOR with DAPA is common in clinical settings. Uridine diphosphate-glucuronosyltransferase family 1 member A9 (UGT1A9) is involved in the metabolism of SOR and dapagliflozin (DAPA), and SOR is the inhibitor of UGT1A1 and UGT1A9 (in vitro). Therefore, changes in UGT1A9 activity caused by SOR may lead to pharmacokinetic interactions between the two drugs. The objective of the current study was to develop an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous determination of SOR and DAPA in plasma and to evaluate the effect of the co-administration of SOR and DAPA on their individual pharmacokinetic properties and the mechanism involved. The rats were divided into four groups: SOR (100 mg/kg) alone and co-administered with DAPA (1 mg/kg) for seven days, and DAPA (1 mg/kg) alone and co-administered with SOR (100 mg/kg) for seven days. Liquid–liquid extraction (LLE) was performed for plasma sample preparation, and the chromatographic separation was conducted on Waters XSelect HSS T3 column with a gradient elution of 0.1% formic acid and 5 mM ammonium acetate (Phase A) and acetonitrile (Phase B). The levels of Ugt1a7 messenger RNA (mRNA) were determined in rat liver and intestine using quantitative real-time polymerase chain reaction (qRT-PCR). The method was successfully applied to the study of pharmacokinetic interactions. DAPA caused a significant decrease in the maximum plasma concentrations (Cmax) and the area under the plasma concentration–time curves (AUC0–t) of SOR by 41.6% and 50.5%, respectively, while the apparent volume of distribution (Vz/F) and apparent clearance (CLz/F) significantly increased 2.85- and 1.98-fold, respectively. When co-administering DAPA with SOR, the AUC0–t and the elimination half-life (t1/2Z) of DAPA significantly increased 1.66- and 1.80-fold, respectively, whereas the CLz/F significantly decreased by 40%. Results from qRT-PCR showed that, compared with control, seven days of SOR pretreatment decreased Ugt1a7 expression in both liver and intestine tissue. In contrast, seven days of DAPA pretreatment decreased Ugt1a7 expression only in liver tissue. Therefore, pharmacokinetic interactions exist between long-term use of SOR with DAPA, and UGT1A9 may be the targets mediating the interaction. Active surveillance for the treatment outcomes and adverse reactions are required.

Pharmacokinetic Interactions between Canagliflozin and Sorafenib or Lenvatinib in Rats

Hepatocellular carcinoma (HCC) and type 2 diabetes mellitus (T2DM) are common clinical conditions, and T2DM is an independent risk factor for HCC. Sorafenib and lenvatinib, two multi-targeted tyrosine kinase inhibitors, are first-line therapies for advanced HCC, while canagliflozin, a sodium-glucose co-transporter 2 inhibitor, is widely used in the treatment of T2DM. Here, we developed an ultra-performance liquid chromatography-tandem mass spectrometry method for the simultaneous determination of canagliflozin, sorafenib, and lenvatinib, and investigated the pharmacokinetic drug interactions between canagliflozin and sorafenib or lenvatinib in rats. The animals were randomly divided into five groups. Groups I–III were gavage administrated with sorafenib, lenvatinib, and canagliflozin, respectively. Group IV received sorafenib and canagliflozin; while Group V received lenvatinib and canagliflozin. The area under the plasma concentration-time curves (AUC) and maximum plasma concentrations (C_max) of canagliflozin increased by 37.6% and 32.8%, respectively, while the apparent volume of distribution (V_z/F) and apparent clearance (CL_z/F) of canagliflozin significantly decreased (30.6% and 28.6%, respectively) in the presence of sorafenib. Canagliflozin caused a significant increase in AUC and C_max of lenvatinib by 28.9% and 36.2%, respectively, and a significant decrease in V_z/F and CL_z/F of lenvatinib by 52.9% and 22.7%, respectively. In conclusion, drug interactions exist between canagliflozin and sorafenib or lenvatinib, and these findings provide a reference for the use of these drugs in patients with HCC and T2DM.

Phase 1 study of sorafenib and irinotecan in pediatric patients with relapsed or refractory solid tumors

BACKGROUND

Sorafenib,an orally bioavailable, multitarget tyrosine kinase inhibitor, and irinotecan, a topoisomerase I inhibitor, have demonstrated activity in pediatric and adult malignancies. We evaluated the toxicity, pharmacokinetic (PK), and pharmacogenomic (PGX) profile of sorafenib with irinotecan in children with relapsed or refractory solid tumors and assessed the feasibility of incorporating patient-reported outcome (PRO) measures as an adjunct to traditional endpoints.

METHODS

Sorafenib, continuous oral twice daily dosing, was administered with irinotecan, orally, once daily days 1-5, repeated every 21 days (NCT01518413). Based on tolerability, escalation of sorafenib followed by escalation of irinotecan was planned. Three patients were initially enrolled at each dose level. Sorafenib and irinotecan PK analyses were performed during cycle 1. PRO measurements were collected during cycles 1 and 2.

RESULTS

Fifteen patients were evaluable. Two of three patients at dose level 2 experienced dose-limiting toxicity (DLT), grade 3 diarrhea, and grade 3 hyponatremia. Therefore, dose level 1 was expanded to 12 patients and two patients had DLT, grade 4 thrombocytopenia, grade 3 elevated lipase. Nine of 15 (60%) patients had a best response of stable disease with four patients receiving ≥6 cycles.

CONCLUSIONS

The recommended dose for pediatric patients was sorafenib 150 mg/m² /dose twice daily with irinotecan 70 mg/m² /dose daily × 5 days every 21 days. This oral outpatient regimen was well tolerated and resulted in prolonged disease stabilization. There were no significant alterations in the PK profile of either agent when administered in combination. Patients were willing and able to report their subjective experiences with this regimen.

How Science Is Driving Regulatory Guidances

This chapter provides regulatory perspectives on how to translate in vitro drug metabolism findings into in vivo drug-drug interaction (DDI) predictions and how this affects the decision of conducting in vivo DDI evaluation. The chapter delineates rationale and analyses that have supported the recommendations in the U.S. Food and Drug Administration (FDA) DDI guidances in terms of in vitro-in vivo extrapolation of cytochrome P450 (CYP) inhibition-mediated DDI potential for investigational new drugs and their metabolites as substrates or inhibitors. The chapter also describes the framework and considerations to assess UDP-glucuronosyltransferase (UGT) inhibition-mediated DDI potential for drugs as substrates or inhibitors. The limitations of decision criteria and further improvements needed are also discussed. Case examples are provided throughout the chapter to illustrate how decision criteria have been utilized to evaluate in vivo DDI potential from in vitro data.

Selection of Oral Therapeutics in China for the Treatment of Colorectal Cancer

OPINION STATEMENT

Intravenous administration of fluoropyrimidine-based chemotherapy has been the backbone of treatment in colorectal cancer (CRC) for decades. The availability of oral capecitabine has improved the tolerability and simplified combination schedules. In addition to capecitabine, several other oral drugs have proven efficacy, particularly in palliative treatment lines. Clinical guidelines describe several available third-line treatment options for metastatic CRC (mCRC), but few insights are provided to guide the selection and sequence. In this review, we describe the available evidence and most recent data concerning oral drugs with proven efficacy in CRC, including antiangiogenetic tyrosine kinase inhibitors (VEGFR TKIs), inhibitors blocking EGFR/Raf/MEK/ERK signaling pathway and modified fluoropyrimidine, and share recommendations and insights on selecting third-line oral therapies for mCRC in China. In general, third-line treatment options for mCRC are mainly regorafenib, fruquintinib, and chemo/targeted therapy reintroduction, while FTD/TPI was rarely used in China probably due to poor accessibility. Fruquintinib is preferred in patients with poor performance status (PS), elder age, and severe organ dysfunction, compared to regorafenib. New drugs of clinical trials were more recommended for the patients with BRAF mutant tumor, and those with good previous treatment efficacy tended to be recommended for chemo/targeted therapy reintroduction. The management of mCRC is evolving, and it must be emphasized that the consideration and recommendations presented here reflect current treatment practices in China and thus might change according to new clinical data as well as the availability of new oral drugs.

TRIM Proteins in Colorectal Cancer: TRIM8 as a Promising Therapeutic Target in Chemo Resistance

Colorectal cancer (CRC) represents one of the most widespread forms of cancer in the population and, as all malignant tumors, often develops resistance to chemotherapies with consequent tumor growth and spreading leading to the patient’s premature death. For this reason, a great challenge is to identify new therapeutic targets, able to restore the drugs sensitivity of cancer cells. In this review, we discuss the role of TRIpartite Motifs (TRIM) proteins in cancers and in CRC chemoresistance, focusing on the tumor-suppressor role of TRIM8 protein in the reactivation of the CRC cells sensitivity to drugs currently used in the clinical practice. Since the restoration of TRIM8 protein levels in CRC cells recovers chemotherapy response, it may represent a new promising therapeutic target in the treatment of CRC.

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.

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.

Sorafenib Plus Irinotecan Combination in Patients With RAS-mutated Metastatic Colorectal Cancer Refractory To Standard Combined Chemotherapies: A Multicenter, Randomized Phase 2 Trial (NEXIRI-2/PRODIGE 27)

BACKGROUND

No treatment option was available for patients with RAS-mutated (RASmt) metastatic colorectal cancer (mCRC) who progress after standard combined chemotherapies at the time of the study. After promising results in phase II, the aim of the present NEXIRI-2/PRODIGE 27 trial was to assess the 2-month non-progression rate for sorafenib (NEX) plus irinotecan (IRI), that is, NEXIRI, treatment.

METHODS

Patients with RASmt mCRC after failure of oxaliplatin, IRI, fluoropyrimidines, and bevacizumab were randomized between NEXIRI (IRI 120-180 mg/m² intravenous, D1 = D15 plus oral NEX 400 mg twice a day) versus IRI (180 mg/m²) versus NEX. Primary endpoint was the 2-month non-progression rate. Secondary endpoints included progression-free and overall survival (PFS and OS), safety, and germline cyclin D1 (CCND1) rs9344 polymorphisms analyses.

RESULTS

A total of 173 patients were included, 59 in NEXIRI, 57 in IRI, and 57 in NEX arms. The 2-month non-progression rate was 52.6% (95% confidence interval [CI]: 39%-66%), 21.4% (10%-33%), and 19.3% (9%-30%) for NEXIRI, IRI, and NEX. Median PFS was 3.6 (95% CI: 2-4.2), 1.7 (1.7-1.8), and 2 (1.8-2.3) months and the median OS was 7.2 (5.8-9.4), 6.3 (4.8-8), and 5.6 (3.9-7.7) months for NEXIRI, IRI, and NEX, respectively. For NEXIRI rs9344CCND1 A/A genotype patients, OS was 19.6 months (95% CI: 4.8-not reached). Main grade 3 toxicities included neutropenia, febrile neutropenia, diarrhea, hand-foot syndrome, and hypertension.

CONCLUSIONS

In patients with RASmt mCRC who progressed after standard combined chemotherapies, the results of 2-month non-progression rate and median PFS in the NEXIRI arm were in favor of an increase of the time before progression.

Enhancement of sorafenib-mediated death of Hepatocellular carcinoma cells by Carnosic acid and Vitamin D2 analog combination

Hepatocellular carcinoma (HCC) is the most common form of liver cancer and it is the third leading cause of global cancer mortality. Sorafenib (Sf) is the first oral multi-kinase inhibitor approved for systemic treatment of advanced HCC, and can prolong survival, although only for three months longer than placebo treated patients. Preclinical studies showed that active forms of vitamin D can induce cell differentiation and regulate cell survival in several cell types, and epidemiological data link vitamin D insufficiency to an increased risk of neoplastic diseases, suggesting a potentially important role of vitamin D in cancer therapy. Other studies showed that the effect of vitamin D analogs on human neoplastic cells is potentiated by carnosic acid (CA), a plant polyphenol with anti-oxidant properties. Here we tested if the addition of the vitamin D2 analog Doxercalciferol (D2) together with CA can enhance the cytotoxic effect of Sf on HCC cell lines Huh7 (Sf-sensitive) and HCO2 (Sf-resistant). Indeed, this combination increased HCC cell death in cell lines, enhancing autophagy as well as apoptosis. Autophagy was confirmed by increased cytoplasmic vacuolation, perinuclear aggregation of LC3, and elevated protein levels of autophagy markers Beclin1, Atg3, and LC3. These results suggest that a regimen which combines a vitamin D2 analog/CA mixture with Sf can be a novel and promising therapeutic option for the treatment of HCC.

Kinase Inhibitors and Ovarian Cancer

Ovarian cancer is fifth in the rankings of cancer deaths among women, and accounts for more deaths than any other gynecological malignancy. Despite some improvement in overall-(OS) and progression-free survival (PFS) following surgery and first-line chemotherapy, there is a need for development of novel and more effective therapeutic strategies. In this mini review, we provide a summary of the current landscape of the clinical use of tyrosine kinase inhibitors (TKIs) and mechanistic target of rapamycin (mTOR) inhibitors in ovarian cancer. Emerging data from phase I and II trials reveals that a combinatorial treatment that includes TKIs and chemotherapy agents seems promising in terms of PFS despite some adverse effects recorded; whereas the use of mTOR inhibitors seems less effective. There is a need for further research into the inhibition of multiple signaling pathways in ovarian cancer and progression to phase III trials for drugs that seem most promising.

Safety and Tolerability of Anti-Angiogenic Protein Kinase Inhibitors and Vascular-Disrupting Agents in Cancer: Focus on Gastrointestinal Malignancies

Angiogenesis is an essential process for tumor growth and metastasis. Inhibition of angiogenesis as an anticancer strategy has shown significant results in a plethora of tumors. Anti-angiogenic agents are currently part of many standard-of-care options for several metastatic gastrointestinal cancers. Bevacizumab, aflibercept, ramucirumab, and regorafenib have significantly improved both progression-free and overall survival in different lines of treatment in metastatic colorectal cancer. Second-line ramucirumab and third-line apatinib are effective anti-angiogenic treatments for patients with metastatic gastric cancer. Unfortunately, the anti-angiogenic strategy has major practical limitations: resistance inevitably develops through redundancy of signaling pathways and selection for subclonal populations adapted for hypoxic conditions. Anti-angiogenic agents may be more effective in combination therapies, with not only cytotoxics but also other emerging compounds in the anti-angiogenic class or in the separate class of the so-called vascular-disrupting agents. This review aims to provide an overview of the approved and "under development" anti-angiogenic compounds as well as the vascular-disrupting agents in the treatment of gastrointestinal cancers, focusing on the actual body of knowledge available on therapy challenges, pharmacodynamic and pharmacokinetic mechanisms, safety profiles, promising predictive biomarkers, and future perspectives.

The UDP-Glycosyltransferase (UGT) Superfamily: New Members, New Functions, and Novel Paradigms

UDP-glycosyltransferases (UGTs) catalyze the covalent addition of sugars to a broad range of lipophilic molecules. This biotransformation plays a critical role in elimination of a broad range of exogenous chemicals and by-products of endogenous metabolism, and also controls the levels and distribution of many endogenous signaling molecules. In mammals, the superfamily comprises four families: UGT1, UGT2, UGT3, and UGT8. UGT1 and UGT2 enzymes have important roles in pharmacology and toxicology including contributing to interindividual differences in drug disposition as well as to cancer risk. These UGTs are highly expressed in organs of detoxification (e.g., liver, kidney, intestine) and can be induced by pathways that sense demand for detoxification and for modulation of endobiotic signaling molecules. The functions of the UGT3 and UGT8 family enzymes have only been characterized relatively recently; these enzymes show different UDP-sugar preferences to that of UGT1 and UGT2 enzymes, and to date, their contributions to drug metabolism appear to be relatively minor. This review summarizes and provides critical analysis of the current state of research into all four families of UGT enzymes. Key areas discussed include the roles of UGTs in drug metabolism, cancer risk, and regulation of signaling, as well as the transcriptional and posttranscriptional control of UGT expression and function. The latter part of this review provides an in-depth analysis of the known and predicted functions of UGT3 and UGT8 enzymes, focused on their likely roles in modulation of levels of endogenous signaling pathways.

Drug-drug interaction potential of antitumor acridine agent C-1748: The substrate of UDP-glucuronosyltransferases 2B7, 2B17 and the inhibitor of 1A9 and 2B7

BACKGROUND

The compound 9-(2'-hydroxyethylamino)-4-methyl-1-nitroacridine (C-1748), the promising antitumor agent developed in our laboratory was determined to undergo phase I metabolic pathways. The present studies aimed to know its biotransformation with phase II enzymes - UDP-glucuronosyltransferases (UGTs) and its potential to be engaged in drug-drug interactions arising from the modulation of UGT activity.

METHODS

UGT-mediated transformations with rat liver (RLM), human liver (HLM), and human intestine (HIM) microsomes and with 10 recombinant human isoenzymes were investigated. Studies on the ability of C-1748 to inhibit UGT were performed with HLM, HT29 colorectal cancer cell homogenate and the selected recombinant UGT isoenzymes. The reactions were monitored using HPLC-UV/Vis method and the C-1748 metabolite structure was determined with ESI-TOF-MS/MS analysis.

RESULTS

Pseudo-molecular ion (m/z 474.1554) and the experiment with β-glucuronidase indicated that O-glucuronide of C-1748 was formed in the presence of microsomal fractions. This reaction was selectively catalyzed by UGT2B7 and 2B17. High inhibitory effect of C-1748 was shown towards isoenzyme UGT1A9 (IC₅₀=39.7μM) and significant but low inhibitory potential was expressed in HT29 cell homogenate (IC₅₀=84.5μM). The mixed-type inhibition mechanism (K_i=17.0μM;K_i'=81.0μM), induced by C-1748 was observed for recombinant UGT1A9 glucuronidation, whereas HT29 cell homogenate resulted in noncompetitive inhibition (K_i=94.6μM).

CONCLUSIONS

The observed UGT-mediated metabolism of C-1748 and its ability to inhibit UGT activity should be considered as the potency for drug resistance and drug-drug interactions in the prospective multidrug therapy.

Implications of ABCG2 Expression on Irinotecan Treatment of Colorectal Cancer Patients: A Review

BACKGROUND

One of the main chemotherapeutic drugs used on a routine basis in patients with metastatic colorectal cancer ((m)CRC) is the topoisomerase-1 inhibitor, irinotecan. However, its usefulness is limited by the pre-existing or inevitable development of resistance. The ATP-binding cassette (ABC) transporter ABCG2/breast cancer resistance protein (BRCP) through its function in xenobiotic clearance might play an important role in irinotecan resistance. With a goal to evaluate the clinical significance of ABCG2 measurements, we here review the current literature on ABCG2 in relation to irinotecan treatment in CRC patients.

RESULTS

Few studies have evaluated the association between ABCG2 gene or protein expression and prognosis in CRC patients. Discordant results were reported. The discrepancies might be explained by the use of different criteria for interpretation of results in the immunohistochemistry studies. Only one large study evaluated the ABCG2 protein expression and efficacy of irinotecan in mCRC (CAIRO study, n = 566). This study failed to demonstrate any correlation between ABCG2 protein expression in the primary tumor and response to irinotecan-based treatment. We recently raised questions on how to evaluate ABCG2 immunoreactivity patterns, and the results in the CAIRO study might be influenced by using a different scoring protocol than the one proposed by us. In contrast, our recent exploratory study of ABCG2 mRNA expression in 580 patients with stage III primary CRC (subgroup from the randomized PETACC-3 study) indicated that high ABCG2 tumor tissue mRNA expression might be predictive for lack of efficacy of irinotecan.

CONCLUSION

The biological role of ABCG2 in predicting clinical irinotecan sensitivity/resistance in CRC is uncertain. In particular, the significance of ABCG2 cellular localization needs to be established. Data concerning ABCG2 mRNA expression and prediction of adjuvant irinotecan efficacy are still sparse and need to be confirmed.

Inefficiencies and Patient Burdens in the Development of the Targeted Cancer Drug Sorafenib: A Systematic Review

Failure in cancer drug development exacts heavy burdens on patients and research systems. To investigate inefficiencies and burdens in targeted drug development in cancer, we conducted a systematic review of all prelicensure trials for the anticancer drug, sorafenib (Bayer/Onyx Pharmaceuticals). We searched Embase and MEDLINE databases on October 14, 2014, for prelicensure clinical trials testing sorafenib against cancers. We measured risk by serious adverse event rates, benefit by objective response rates and survival, and trial success by prespecified primary endpoint attainment with acceptable toxicity. The first two clinically useful applications of sorafenib were discovered in the first 2 efficacy trials, after five drug-related deaths (4.6% of 108 total) and 93 total patient-years of involvement (2.4% of 3,928 total). Thereafter, sorafenib was tested in 26 indications and 67 drug combinations, leading to one additional licensure. Drug developers tested 5 indications in over 5 trials each, comprising 56 drug-related deaths (51.8% of 108 total) and 1,155 patient-years (29.4% of 3,928 total) of burden in unsuccessful attempts to discover utility against these malignancies. Overall, 32 Phase II trials (26% of Phase II activity) were duplicative, lacked appropriate follow-up, or were uninformative because of accrual failure, constituting 1,773 patients (15.6% of 11,355 total) participating in prelicensure sorafenib trials. The clinical utility of sorafenib was established early in development, with low burden on patients and resources. However, these early successes were followed by rapid and exhaustive testing against various malignancies and combination regimens, leading to excess patient burden. Our evaluation of sorafenib development suggests many opportunities for reducing costs and unnecessary patient burden in cancer drug development.

Targeting Angiogenesis in Colorectal Cancer: Tyrosine Kinase Inhibitors

Colorectal cancer is commonly diagnosed throughout the world, and treatment options have greatly expanded over the last 2 decades. Targeting angiogenesis has been a major focus of study in a variety of malignancy types. Targeting angiogenesis has been achieved by several mechanisms in colorectal cancer, including use of antiangiogenic small molecule tyrosine kinase inhibitors (TKIs). There have been many attempts and failures to prove efficacy of TKIs in the treatment of colorectal cancer including sorafenib, sunitinib, vatalanib, and tivozanib. Regorafenib was the first TKI to demonstrate efficacy and is an orally active inhibitor of angiogenic (including the vascular endothelial growth factor receptors 1, 2, and 3), stromal, and oncogenic receptor tyrosine kinases. There are ongoing investigations of both regorafenib and ninetanib; however, there remains a critical need to better understand novel combinations with TKIs that could prove more efficacious than available options.

Comprehensive Analysis of miRNome Alterations in Response to Sorafenib Treatment in Colorectal Cancer Cells

MicroRNAs (miRNAs) are master regulators of drug resistance and have been previously proposed as potential biomarkers for the prediction of therapeutic response in colorectal cancer (CRC). Sorafenib, a multi-kinase inhibitor which has been approved for the treatment of liver, renal and thyroid cancer, is currently being studied as a monotherapy in selected molecular subtypes or in combination with other drugs in metastatic CRC. In this study, we explored sorafenib-induced cellular effects in Kirsten rat sarcoma viral oncogene homolog olog (KRAS) wild-type and KRAS-mutated CRC cell lines (Caco-2 and HRT-18), and finally profiled expression changes of specific miRNAs within the miRNome (>1000 human miRNAs) after exposure to sorafenib. Overall, sorafenib induced a time- and dose-dependent growth-inhibitory effect through S-phase cell cycle arrest in KRAS wild-type and KRAS-mutated CRC cells. In HRT-18 cells, two human miRNAs (hsa-miR-597 and hsa-miR-720) and two small RNAs (SNORD 13 and hsa-miR-3182) were identified as specifically sorafenib-induced. In Caco-2 cells, nine human miRNAs (hsa-miR-3142, hsa-miR-20a, hsa-miR-4301, hsa-miR-1290, hsa-miR-4286, hsa-miR-3182, hsa-miR-3142, hsa-miR-1246 and hsa-miR-720) were identified to be differentially regulated post sorafenib treatment. In conclusion, we confirmed sorafenib as a potential anti-neoplastic treatment strategy for CRC cells by demonstrating a growth-inhibitory and cell cycle–arresting effect of this drug. Changes in the miRNome indicate that some specific miRNAs might be relevant as indicators for sorafenib response, drug resistance and potential targets for combinatorial miRNA-based drug strategies.

Pharmacokinetic Aspects of Vascular Endothelial Growth Factor Tyrosine Kinase Inhibitors

Scientists have identified the impact of angiogenesis on tumor growth and survival. Among other efficient drugs, several small-molecule tyrosine kinase inhibitors (TKIs) targeting the vascular endothelial growth factor receptor (VEGFR) have been developed and have already been integrated into the treatment of various advanced malignancies. This review provides a compilation of current knowledge on the pharmacokinetic aspects of all VEGFR-TKIs already approved by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) and of those still under investigation. Additional information on substance metabolism, potential for drug-drug interactions (DDIs), and the need for dose adaptation in patients with predominant renal and/or hepatic impairment has been included. All TKIs introduced in this review were administered orally, allowing for easy drug handling for healthcare professionals and patients. For almost all substances, the maximum plasma concentrations were reached within a short period of time. The majority of the substances showed a high plasma protein binding and their excretion occurred via the feces and, to a lesser extent, via the urine. In most cases, dose adaptation in patients with mild to moderate renal or hepatic impairment is not recommended. Cytochrome P450 (CYP) 3A4 was found to play a crucial role in the drug metabolic processes of many compounds. In order to prevent unwanted DDIs, co-administration of VEGFR TKIs together with CYP3A4 inhibitors or inducers should be avoided. Throughout all TKIs, the data indicate high inter-individual variability. The causes of this are still unclear and require further research to allow for individualization of treatment regimens.

UGT genotyping in belinostat dosing

Certain genetic polymorphisms of UDP glucuronosyltransferase 1 family, polypeptide A1 (UGT1A1) can reduce gene expression (*28, *60, *93) or activity (*6), thereby altering the pharmacokinetics, pharmacodynamics, and the risk of toxicities of UGT1A1 substrates, of which irinotecan is a widely-described example. This review presents an overview of the clinical effects of UGT1A1 polymorphisms on the pharmacology of UGT1A1 substrates, with a special focus on the novel histone deacetylase inhibitor belinostat. Belinostat, approved for the treatment of peripheral T-cell lymphoma, is primarily glucuronidated by UGT1A1. Recent preclinical and clinical data showed that UGT1A1*28 was associated with reduced glucuronidation in human liver microsomes, while in a retrospective analysis of a Phase I trial with patients receiving belinostat UGT1A1*60 was predominantly associated with increased belinostat plasma concentrations. Furthermore, both UGT1A1*28 and *60 variants were associated with increased incidence of thrombocytopenia and neutropenia. Using population pharmacokinetic analysis a 33% dose reduction has been proposed for patients carrying UGT1A1 variant alleles. Clinical effects of this genotype-based dosing recommendation is currently prospectively being investigated. Overall, the data suggest that UGT1A1 genotyping is useful for improving belinostat therapy.

Etirinotecan pegol: development of a novel conjugated topoisomerase I inhibitor

Irinotecan is a very active chemotherapeutic agent used for the treatment of several malignancies, including colorectal cancer, gastroesophageal tumors, lung cancer, breast cancer, ovarian cancer, and primary brain tumors. Irinotecan exerts its antineoplastic effects through its active metabolite 7-ethyl-10-hydroxycamptothecin. This metabolite is also responsible for the classic side effects associated with irinotecan that include diarrhea and neutropenia. A pegylated form of this agent, etirinotecan pegol, is undergoing clinical development with the main goal of increasing its therapeutic efficacy and its safety. This agent decreases the maximal exposure to 7-ethyl-10-hydroxycamptothecin while providing continuous exposure to the treated tumor. The half-life of etirinotecan pegol is 50 days and it has been studied in different schedules: weekly, every other week, and once every 3 weeks. The maximum tolerated dose of etirinotecan pegol was found to be 145 mg/m(2). There have already been two phase II clinical trials published showing the efficacy of this novel agent in the treatment of metastatic ovarian and breast cancer. The side effect profile was acceptable for most patients, with a number of patients experiencing diarrhea and even neutropenia.

Sorafenib and thyroid cancer

Sorafenib (Nexavar) is a multikinase inhibitor, which has demonstrated both anti-proliferative and anti-angiogenic properties in vitro and in vivo, inhibiting the activity of targets present in the tumor cell [c-RAF (proto-oncogene serine/threonine-protein kinase), BRAF, (V600E)BRAF, c-KIT, and FMS-like tyrosine kinase 3] and in tumor vessels (c-RAF, vascular endothelial growth factor receptor-2, vascular endothelial growth factor receptor-3, and platelet-derived growth factor receptor β). For several years, sorafenib has been approved for the treatment of hepatocellular carcinoma and advanced renal cell carcinoma. After previous studies showing that sorafenib was able to inhibit oncogenic RET mutants, (V600E)BRAF, and angiogenesis and growth of orthotopic anaplastic thyroid cancer xenografts in nude mice, some clinical trials demonstrated the effectiveness of sorafenib in advanced thyroid cancer. Currently, the evaluation of the clinical safety and efficacy of sorafenib for the treatment of advanced thyroid cancer is ongoing. This article reviews the anti-neoplastic effect of sorafenib in thyroid cancer. Several completed (or ongoing) studies have evaluated the long-term efficacy and tolerability of sorafenib in patients with papillary and medullary aggressive thyroid cancer. The results suggest that sorafenib is a promising therapeutic option in patients with advanced thyroid cancer that is not responsive to traditional therapeutic strategies.

What could Nintedanib (BIBF 1120), a triple inhibitor of VEGFR, PDGFR, and FGFR, add to the current treatment options for patients with metastatic colorectal cancer?

Increasing knowledge of the pro-angiogenic processes involved in the progression of metastatic colorectal cancer (mCRC) has resulted in the clinical development of several anti-angiogenic agents, with bevacizumab currently being the only approved agent for mCRC. Nintedanib (BIBF 1120) has been shown to block the vascular endothelial growth factor receptor (VEGFR), the platelet-derived growth factor receptor (PDGFR), and the fibroblast growth factor receptor (FGFR). By targeting FGFR signaling, nintedanib may overcome resistance to previous anti-VEGF treatments, and may represent a better approach in patients with high basal levels of circulating FGFs. In this article, the angiogenic mechanisms implicated in mCRC are reviewed (focusing on the signaling pathways activated by VEGFR, PDGFR, and FGFR), along with the clinical data for nintedanib in the context of other anti-angiogenic tyrosine kinase inhibitors under clinical development for mCRC. Biomarkers that could predict response to nintedanib are also discussed.

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.

Sorafenib and irinotecan (NEXIRI) as second- or later-line treatment for patients with metastatic colorectal cancer and KRAS-mutated tumours: a multicentre Phase I/II trial

Background:

This trial evaluated the feasibility and efficacy of combined sorafenib and irinotecan (NEXIRI) as second- or later-line treatment of patients with KRAS-mutated metastatic colorectal cancer (mCRC), who had progressed after irinotecan-based chemotherapy.

Methods:

In Phase I, in a 3+3 dose escalation schedule, patients received irinotecan (125, 150 or 180 mg m⁻² every 2 weeks), in combination with 400 mg sorafenib b.d. The primary end point was the maximum-tolerated dose of irinotecan. In Phase II, the primary end point was disease control rate (DCR). Secondary end points were progression-free survival (PFS), overall survival (OS) and toxicity.

Results:

Phase I included 10 patients (median age 63 (49–73)); no dose-limiting toxicity was seen. In Phase II, 54 patients (median age 60 (43–80) years) received irinotecan 180 mg m⁻² every 2 weeks with sorafenib 400 mg b.d. Nine patients (17%) remained on full-dose sorafenib. The DCR was 64.9% (95% CI, 51–77). Median PFS and OS were 3.7 (95% CI, 3.2–4.7) and 8.0 (95% CI, 4.8–9.7) months, respectively. Toxicities included Grade 3 diarrhoea (37%), neutropenia (18%), hand-foot syndrome (13%) and Grade 4 neutropenia (17%).

Conclusion:

The NEXIRI regimen showed promising activity as second- or later-line treatment in this heavily pretreated mCRC population (ClinicalTrials.gov NCT00989469).

Sorafenib: targeting multiple tyrosine kinases in cancer

Sorafenib (BAY 43-9006, Nexavar®) is an oral multiple tyrosine kinase inhibitor. Main targets are receptor tyrosine kinase pathways frequently deregulated in cancer such as the Raf-Ras pathway, vascular endothelial growth factor (VEGF) pathway, and FMS-like tyrosine kinase 3 (FLT3). Sorafenib was approved by the FDA in fast track for advanced renal cell cancer and hepatocellular cancer and shows good clinical activity in thyroid cancer. Multiple clinical trials are undertaken to further investigate the role of sorafenib alone or in combination for the treatment of various tumor entities.

Drug interactions with solid tumour-targeted therapies

Drug interactions are an on-going concern in the treatment of cancer, especially when targeted therapies, such as tyrosine kinase inhibitors (TKI) or mammalian target of rapamycin (mTOR) inhibitors, are being used. The emergence of elderly patients and/or patients with both cancer and other chronic co-morbidities leads to polypharmacy. Therefore, the risk of drug-drug interactions (DDI) becomes a clinically relevant issue, all the more so as TKIs and mTOR inhibitors are essentially metabolised by cytochrome P450 enzymes. These DDIs can result in variability in anticancer drug exposure, thus favouring the selection of resistant cellular clones or the occurrence of toxicity. This review provides a comprehensive overview of DDIs that involve targeted therapies approved by the FDA for the treatment of solid tumours for more than 3 years (sorafenib, sunitinib, erlotinib, gefitinib, imatinib, lapatinib, everolimus, temsirolimus) and medicinal herb or drugs. This review also provides some guidelines to help oncologists and pharmacists in their clinical practice.

Personalizing colon cancer therapeutics: targeting old and new mechanisms of action

The use of pharmaceuticals for colon cancer treatment has been increasingly personalized, in part due to the development of new molecular tools. In this review, we discuss the old and new colon cancer chemotherapeutics, and the parameters that have been shown to be predictive of efficacy and safety of these chemotherapeutics. In addition, we discuss how alternate pharmaceuticals have been developed in light of a potential lack of response or resistance to a particular chemotherapeutic.

Sorafenib overcomes irinotecan resistance in colorectal cancer by inhibiting the ABCG2 drug-efflux pump

Despite recent advances in the treatment of colorectal cancer (CRC), tumor resistance is a frequent cause of chemotherapy failure. Therefore, new treatment options are needed to improve survival of patients with irinotecan-refractory CRCs, particularly those bearing KRAS mutations that preclude the use of anti-EGFR therapies. In this study, we investigated whether sorafenib could reverse irinotecan resistance, thereby enhancing the therapeutic efficacy of routinely used irinotecan-based chemotherapy. We used both in vitro (the HCT116, SW48, SW620, and HT29 colon adenocarcinoma cell lines and four SN-38-resistant HCT-116 and SW48 clones) and in vivo models (nude mice xenografted with SN-38-resistant HCT116 cells) to test the efficacy of sorafenib alone or in combination with irinotecan or its active metabolite, SN-38. We have shown that sorafenib improved the antitumoral activity of irinotecan in vitro, in both parental and SN-38-resistant colon adenocarcinoma cell lines independently of their KRAS status, as well as in vivo, in xenografted mice. By inhibiting the drug-efflux pump ABCG2, sorafenib favors irinotecan intracellular accumulation and enhances its toxicity. Moreover, we found that sorafenib improved the efficacy of irinotecan by inhibiting the irinotecan-mediated p38 and ERK activation. In conclusion, our results show that sorafenib can suppress resistance to irinotecan and suggest that sorafenib could be used to overcome resistance to irinotecan-based chemotherapies in CRC, particularly in KRAS-mutated tumors.

Molecularly targeted therapies in metastatic pancreatic cancer: a systematic review

Pancreatic cancer is the fourth leading cause of cancer-related death. Most patients present with an advanced stage of disease that has a dismal outcome, with a median survival of approximately 6 months. Evidently, there is a clear need for the development of new agents with novel mechanisms of action in this disease. A number of biological agents modulating different signal transduction pathways are currently in clinical development, inhibiting angiogenesis and targeting epidermal growth factor receptor, cell cycle, matrix metalloproteinases, cyclooxygenase-2, mammalian target of rapamycin, or proteasome. This is the first systematic review of the literature to synthesize all available data coming from trials and evaluate the efficacy and safety of molecular targeted drugs in unresectable and metastatic pancreatic cancer. However, it should be stressed that although multiple agents have been tested, only 9 phase 3 trials have been conducted and one agent (erlotinib) has been approved by the Food and Drug Administration for use in clinical practice. As knowledge accumulates on the molecular mechanisms underlying carcinogenesis in the pancreas, the anticipated development and assessment of molecularly targeted agents may offer a promising perspective for a disease which, to date, remains incurable.

Sorafenib in combination with oxaliplatin, leucovorin, and fluorouracil (modified FOLFOX6) as first-line treatment of metastatic colorectal cancer: the RESPECT trial

PURPOSE

This randomized, double-blind, placebo-controlled, phase IIb study evaluated adding sorafenib to first-line modified FOLFOX6 (mFOLFOX6) for metastatic colorectal cancer (mCRC).

EXPERIMENTAL DESIGN

Patients were randomized to sorafenib (400 mg b.i.d.) or placebo, combined with mFOLFOX6 (oxaliplatin 85 mg/m(2); levo-leucovorin 200 mg/m(2); fluorouracil 400 mg/m(2) bolus and 2400 mg/m(2) continuous infusion) every 14 days. Primary endpoint was progression-free survival (PFS). Target sample was 120 events in 180 patients for >85% power (two-sided α = 0.20) to detect an HR = 0.65.

RESULTS

Of 198 patients randomized, median PFS for sorafenib plus mFOLFOX6 was 9.1 months versus 8.7 months for placebo plus mFOLFOX6 (HR = 0.88; 95% CI, 0.64-1.23; P = 0.46). There was no difference between treatment arms for overall survival. Subgroup analyses of PFS and overall survival showed no difference between treatment arms by KRAS or BRAF status (mutant and wild type). The most common grade 3/4 adverse events in the sorafenib and placebo arms were neutropenia (48% vs. 22%), peripheral neuropathy (16% vs. 21%), and grade 3 hand-foot skin reaction (20% vs. 0%). Treatment discontinuation because of adverse events was 9% and 6%, respectively. Generally, dose intensity (duration and cumulative doses) was lower in the sorafenib arm than in the placebo arm.

CONCLUSION

This study did not detect a PFS benefit with the addition of sorafenib to first-line mFOLFOX6 for mCRC. KRAS and BRAF status did not seem to impact treatment outcomes but the subgroups were small. These results do not support further development of sorafenib in combination with mFOLFOX6 in molecularly unselected patients with mCRC.

Regorafenib in combination with FOLFOX or FOLFIRI as first- or second-line treatment of colorectal cancer: results of a multicenter, phase Ib study

Background

Metastatic colorectal cancer (mCRC) is commonly treated with 5-fluorouracil, folinic acid, and oxaliplatin or irinotecan. The multitargeted kinase inhibitor, regorafenib, was combined with chemotherapy as first- or second-line treatment of mCRC to assess safety and pharmacokinetics (primary objectives) and tumor response (secondary objective).

Patients and methods

Forty-five patients were treated every 2 weeks with 5-fluorouracil 400 mg/m² bolus then 2400 mg/m² over 46 h, folinic acid 400 mg/m², and either oxaliplatin 85 mg/m² or irinotecan 180 mg/m². On days 4–10, patients received regorafenib 160 mg orally once daily.

Results

The median duration of treatment was 108 (range 2–345 days). Treatment was stopped for adverse events or death (17 patients), disease progression (11 patients), and consent withdrawal or investigator decision (11 patients). Six patients remained on regorafenib at data cutoff (two without chemotherapy). Drug-related adverse events occurred in 44 patients [grade ≥3 in 32 patients: mostly neutropenia (17 patients) and leukopenia, hand–foot skin reaction, and hypophosphatemia (four patients each)]. Thirty-three patients achieved disease control (partial response or stable disease) for a median of 126 (range 42–281 days).

Conclusion

Regorafenib had acceptable tolerability in combination with chemotherapy, with increased exposure of irinotecan and SN-38 but no significant effect on 5-fluorouracil or oxaliplatin pharmacokinetics.

Single-agent therapy with sorafenib or 5-FU is equally effective in human colorectal cancer xenograft--no benefit of combination therapy

BACKGROUND

We initiated this preclinical study in order to analyze the impact of sorafenib single treatment versus combination treatment in human colorectal cancer.

METHODS

The effect of increasing sorafenib doses on proliferation, apoptosis, migration, and activation of signal cascades was analyzed in vitro. The effect of sorafenib single treatment versus 5-fluorouracil (5-FU) single treatment and combination therapy on in vivo proliferation and target cytokine receptor/ligand expression was analyzed in a human colon cancer xenograft mouse model using HT29 tumor cells.

RESULTS

In vitro, SW480 and HT29 cell lines were sensitive to sorafenib, as compared to Caco2 and SW620 cell lines, independent of the mutation status of K-ras, Raf, PTEN, or PI3K. The effect on migration was marginal, but distinct differences in caspases activation were seen. Combination strategies were beneficial in some settings (sorafenib + 5-FU; irinotecan) and disadvantageous in others (sorafenib + oxaliplatin), depending on the chemotherapeutic drug and cell line chosen. Sensitive cell lines revealed a downregulation of AKT and had a weak expression level of GADD45β. In resistant cell lines, pp53 and GADD45β levels decreased upon sorafenib exposure. In vivo, the combination treatment of sorafenib and 5-FU was equally effective as the respective monotherapy concerning tumor proliferation. Interestingly, treatment with either sorafenib or 5-FU resulted in a significant decrease of VEGFR1 and PDGFRβ expression intensity.

CONCLUSIONS

In colorectal cancer, a sensitivity towards sorafenib exists, which seems similarly effective as a 5-FU monotherapy. A combination therapy, in contrast, does not show any additional effect.

Phase II study of sorafenib in combination with cisplatin and 5-fluorouracil to treat recurrent or metastatic nasopharyngeal carcinoma

BACKGROUND

We aimed to investigate the efficacy and tolerability of sorafenib combined with cisplatin and 5-fluorouracil (5-FU) in patients with recurrent or metastatic nasopharyngeal carcinoma (NPC).

PATIENTS AND METHODS

It was a Simon two-stage designed trial. Chemotherapy-naive patients with recurrent or metastatic disease were enrolled. The regimen was sorafenib 400 mg orally b.i.d., cisplatin 80 mg/m(2) i.v. day 1, and 5-FU 1000 mg/m(2)/day CIV for 4 days, repeated every 21 days. After a maximum of six cycles of chemotherapy, patients received maintenance of sorafenib.

RESULTS

In total, 54 patients were enrolled. The objective response rate reached 77.8%, including 1 complete response and 41 partial responses. The median progression-free survival was 7.2 months (95% CI 6.8-8.4 months), and the median overall survival was 11.8 months (95% CI 10.6-18.7 months). Major toxic effects included hand-foot skin reaction, myelosuppression, and gastrointestinal (GI) reaction. The incidence of hemorrhage was 22.2%, and one patient with liver metastases died of GI bleeding. Contrast-enhanced ultrasonography was carried out in a subset of patients with liver metastases.

CONCLUSION

Combination of sorafenib, cisplatin (80 mg/m(2)) and 5-FU (3000 mg/m(2)) was tolerable and feasible in recurrent or metastatic NPC. Further randomized trials to compare sorafenib plus cisplatin and 5-FU with standard dose of cisplatin plus 5-FU in NPC are warranted.

Phase I study of sorafenib in combination with docetaxel and prednisone in chemo-naïve patients with metastatic castration-resistant prostate cancer

PURPOSE

We performed a dose-escalation study to investigate the safety of sorafenib in combination with docetaxel and prednisone in chemo-naïve patients with metastatic castration-resistant prostate cancer (mCRPC).

METHODS

Six patients were included per dose level. Following docetaxel infusion on day 1 (75 mg/m(2)/q3 weeks), sorafenib was administered at 200 mg BID on days 2-19 (dose level 1), at 200 mg BID on days 1-21 (dose level 2), at 400 mg BID on days 2-19 (dose level 3), at 400 mg BID on days 1-21 (dose level 4). Maximal tolerated dose (MTD) was exceeded if ≥2 patients experienced dose-limiting toxicities (DLT) during cycle 1. The recommended phase 2 dose for sorafenib was defined as one dose level below MTD. If MTD was not reached, the highest feasible dose would be selected to treat an expanded cohort to confirm safety.

RESULTS

Two DLTs were observed during sorafenib dose-escalation consisting of grade 4 febrile neutropenia (dose level 2) and grade 3 hand-foot syndrome (HFS) (dose level 3). Our pharmacokinetic results showed an increased exposure to docetaxel across all dose levels during sorafenib comedication. The main grade ≥3 toxicities were neutropenia (35 %), HFS (27 %), and febrile neutropenia (19 %). The prostate-specific antigen (PSA) response rate was 74 %. Median overall survival was 25.2 months.

CONCLUSION

Three-weekly docetaxel and prednisone could be combined with sorafenib at 400 mg BID on days 1-21 without reaching MTD. However, we observed a pharmacokinetic interaction between sorafenib and docetaxel, associated with significant toxicities, raising concerns about the safety of this combination in mCRPC.

Phase I pharmacokinetic and pharmacodynamic study of cetuximab, irinotecan and sorafenib in advanced colorectal cancer

Background This phase Ib study was designed to determine the maximum tolerated doses (MTD) and dose limiting toxicities (DLTs) of irinotecan and cetuximab with sorafenib. Secondary objectives included characterizing the pharmacokinetics and pharmacodynamics and evaluating preliminary antitumor activity in patients with advanced colorectal cancer (CRC). Methods Patients with metastatic, pretreated CRC were treated at five dose levels. Results Eighteen patients were recruited with median age 56.5 years. In the first five patients treated, 2 irinotecan related DLTs were observed. With reduced dose intensity irinotecan, there were no further DLTs. The most common toxicities were diarrhea, nausea/vomiting, fatigue, anorexia and rash. DLTs included neutropenia and thrombocytopenia. Two patients had partial responses (one with a KRAS mutation) and 8 had stable disease (8-36 weeks). The median progression free survival (PFS) and overall survival (OS) were 2.5 and 4.7 months respectively. Pharmacokinetic analyses suggest sorafenib and metabolite exposure correlate with OS and DLTs. Conclusions The recommended phase II dose (RP2D) is irinotecan 100 mg/m(2) i.v. days 1, 8; cetuximab 400 mg/m(2) i.v. days 1 and 250 mg/m(2) i.v. weekly; and sorafenib 400 mg orally twice daily in advanced, pretreated CRC. The combination resulted in a modest response rate.

Sorafenib is an inhibitor of UGT1A1 but is metabolized by UGT1A9: implications of genetic variants on pharmacokinetics and hyperbilirubinemia

PURPOSE

Several case reports suggest sorafenib exposure and sorafenib-induced hyperbilirubinemia may be related to a (TA)(5/6/7) repeat polymorphism in UGT1A1*28 (UGT, uridine glucuronosyl transferase). We hypothesized that sorafenib inhibits UGT1A1 and individuals carrying UGT1A1*28 and/or UGT1A9 variants experience greater sorafenib exposure and greater increase in sorafenib-induced plasma bilirubin concentration.

EXPERIMENTAL DESIGN

Inhibition of UGT1A1-mediated bilirubin glucuronidation by sorafenib was assessed in vitro. UGT1A1*28 and UGT1A9*3 genotypes were ascertained with fragment analysis or direct sequencing in 120 cancer patients receiving sorafenib on five different clinical trials. Total bilirubin measurements were collected in prostate cancer patients before receiving sorafenib (n = 41) and 19 to 30 days following treatment and were compared with UGT1A1*28 genotype.

RESULTS

Sorafenib exhibited mixed-mode inhibition of UGT1A1-mediated bilirubin glucuronidation (IC(50) = 18 μmol/L; K(i) = 11.7 μmol/L) in vitro. Five patients carrying UGT1A1*28/*28 (n = 4) or UGT1A9*3/*3 (n = 1) genotypes had first dose, dose-normalized areas under the sorafenib plasma concentration versus time curve (AUC) that were in the 93rd percentile, whereas three patients carrying UGT1A1*28/*28 had AUCs in the bottom quartile of all genotyped patients. The Drug Metabolizing Enzymes and Transporters genotyping platform was applied to DNA obtained from six patients, which revealed the ABCC2-24C>T genotype cosegregated with sorafenib AUC phenotype. Sorafenib exposure was related to plasma bilirubin increases in patients carrying 1 or 2 copies of UGT1A1*28 alleles (n = 12 and n = 5; R(2) = 0.38 and R(2) = 0.77; P = 0.032 and P = 0.051, respectively). UGT1A1*28 carriers showed two distinct phenotypes that could be explained by ABCC2-24C>T genotype and are more likely to experience plasma bilirubin increases following sorafenib if they had high sorafenib exposure.

CONCLUSIONS

This pilot study indicates that genotype status of UGT1A1, UGT1A9, and ABCC2 and serum bilirubin concentration increases reflect abnormally high AUC in patients treated with sorafenib.

Phase I trial to investigate the safety, pharmacokinetics and efficacy of sorafenib combined with docetaxel in patients with advanced refractory solid tumours

AIM

The safety, pharmacokinetics and efficacy of sorafenib plus docetaxel in patients with advanced refractory cancer were investigated in a phase I, dose-escalation trial.

METHODS

Twenty-seven patients in four cohorts received docetaxel on day 1 (cohorts 1 and 4: 75 mg/m2; cohorts 2 and 3: 100 mg/m2) plus sorafenib on days 2-19 (cohorts 1 and 2: 200 mg twice-daily (bid); cohorts 3 and 4: 400 mg bid) in 21-day cycles.

RESULTS

Most common adverse events (AEs) (grade 3-5) included neutropenia (89%), leucopaenia (81%), hand-foot skin reaction (30%) and fatigue (30%). The most common drug-related AEs leading to dose reduction/interruption or permanent discontinuation were dermatologic (41%), gastrointestinal (26%) and constitutional (22%). Coadministration of sorafenib altered the pharmacokinetics of docetaxel. On average, docetaxel area under the concentration-time curve (AUC)(0-24) increased by 5% (cohort 1), 54% (cohort 2), 36% (Cohort 3) and 80% (cohort 4) with docetaxel plus sorafenib, while C(max) increased by 16-32%, independent of sorafenib/docetaxel doses. Three of 25 evaluable patients (11%) had partial responses; 14 (52%) had stable disease.

CONCLUSION

Dose-limiting dermatologic AEs were more common than expected for either therapy alone. A starting dose of docetaxel 75 mg/m2 plus sorafenib 400mg bid (with dose reductions for dermatological toxicities) is proposed for phase II.

Inhibition of paracetamol glucuronidation by tyrosine kinase inhibitors

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Clinical cases reported that fatal acute liver failure occurred when paracetamol (acetaminophen) was co-administrated with some tyrosine kinase inhibitors (TKIs). The direct inhibition of UDP-glucuronosyltransferase activities has been identified as a mechanism of potentiation of paracetamol hepatotoxicity. However, the effects of TKIs on paracetamol glucuronidation are not known.

WHAT THIS STUDY ADDS

• The TKIs, sorafenib, dasatinib and imatinib exhibited potent mixed inhibition against paracetamol glucuronidation in pooled human liver microsomes, implying a possible increase in paracetamol hepatotoxicity when they are co-administrated with paracetamol. AIMS We aimed to investigate the effects of tyrosine kinase inhibitors (TKIs) on paracetamol (acetaminophen) glucuronidation.

METHODS

The inhibition of nine small molecule TKIs on paracetamol glucuronidation was investigated in human liver microsomes (HLMs) and recombinant human UDP-glucuronosyltransferases (UGTs).

RESULTS

Sorafenib, dasatinib and imatinib exhibited mixed inhibition against paracetamol glucuronidation in pooled HLMs, and potent inhibition in UGT1A9 and UGT2B15. Dasatinib and imatinib also inhibited UGT1A1-mediated paracetamol glucuronidation. Axitinib, erlotinib, gefitinib, lapatinib, nilotinib and vandetanib exhibited weak inhibition of paracetamol glucuronidation activity in HLMs.

CONCLUSIONS

The inhibition of paracetamol glucuronidation by TKIs might be of particular concern when they are co-administered.

Angiogenesis inhibitors for the treatment of ovarian cancer

BACKGROUND

Many women with ovarian cancer eventually develop resistance to conventional chemotherapy drugs, and so novel agents are being developed to target specific molecular pathways. One such class of drugs inhibits angiogenesis (the development of new blood vessels), which is essential for tumour growth. It is important to establish whether the addition of these new drugs to conventional chemotherapy regimens improves survival, and what the side-effects may be.

OBJECTIVES

To compare the effectiveness and toxicities of angiogenesis inhibitors in the treatment of ovarian cancer.

SEARCH STRATEGY

We sought to identify completed randomised controlled trials (RCTs) by searching The Cochrane Gynaecological Cancer Review Group's Trial Register, The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 10), MEDLINE and EMBASE (1990 to October 2010). We also searched registers of clinical trials, and contacted investigators of completed and ongoing trials for further information.

SELECTION CRITERIA

Randomised controlled studies comparing angiogenesis inhibitors with either standard chemotherapy or no treatment, in women with ovarian cancer.

DATA COLLECTION AND ANALYSIS

Two independent authors carried out data collection and extraction. We used a random-effects model for pooling data.

MAIN RESULTS

We did not find any fully-published, completed RCTs of angiogenesis inhibitors that met our inclusion criteria. We identified five abstracts of completed RCTs of four different angiogenesis-inhibiting agents, with a total of 3701 participants.Meta-analysis of two trials found no statistically significant difference in overall survival (OS) between women with newly-diagnosed advanced ovarian cancer who received concurrent and maintenance bevacizumab compared to those who received chemotherapy (carboplatin and paclitaxel) alone. However, women who received concurrent and maintenance bevacizumab had their risk of disease progression reduced by a quarter (hazard ratio (HR) 0.75, 95% confidence interval (CI) 0.68 to 0.83; P < 0.001); they also had a significantly increased risk of severe gastrointestinal adverse events, moderate or severe hypertension and severe bleeding.One trial also compared chemotherapy to concurrent (but not maintenance bevacizumab), and found no statistically significant difference in OS or progression-free survival (PFS).  However, the women who received bevacizumab had a significantly higher risk of moderate or severe hypertension.A three-armed RCT, of paclitaxel alone or with low- or high-dose AMG 386, in women with recurrent ovarian cancer, found no statistically significant difference in OS. However, women who received low-dose AMG 386 had a third less risk of disease progression than those who received placebo (HR 0.57, 95% CI 0.36 to 0.91; P = 0.02). The trial found no evidence of increased adverse events in the intervention arms.Two relatively small RCTs (one of VEGF-Trap, the other of BIBF 1120) found no evidence of either significant survival benefit or increased severe adverse events, compared to placebo, but they both lacked statistical power. All five trials had unclear risk of bias, largely because they have only been published in abstract form, and thus many methodological details are unclear. We identified twelve suitable ongoing trials.

AUTHORS' CONCLUSIONS

There is, as yet, no fully-published RCT evidence for the efficacy or safety of angiogenesis inhibitors for the treatment of ovarian cancer, but some preliminary results are available from five trials. There is some evidence from a meta-analysis of two trials that the addition of concurrent and maintenance bevacizumab to standard chemotherapy may reduce the risk of disease progression, in women with newly-diagnosed advanced ovarian cancer. There is also some evidence from a single trial that low-dose AMG 386 may reduce the risk of disease progression in women with recurrent ovarian cancer. However, there is currently no evidence that angiogenesis inhibitors improve OS, nor is there enough evidence to justify the routine use of angiogenesis inhibitors in treating women with ovarian cancer. We eagerly await both the more detailed results of these five completed trials, and the preliminary results of the several ongoing trials.