Phase I, First-in-Human, Dose-Escalation Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of Vorolanib in Patients with Advanced Solid Tumors

Lessons Learned.

Pharmacokinetic results underscore that the vorolanib (X‐82) study design was successful without the need for further dose escalation beyond 400 mg once daily (q.d.).

Therefore, the recommended dose of X‐82 as a single agent in patients with advanced cancer is 400 mg q.d.

Background.

Vorolanib (X‐82) is a novel, oral, multikinase vascular endothelial growth factor (VEGF) receptor/platelet‐derived growth factor (PDGF) receptor inhibitor that was developed on the same chemical scaffold as sunitinib, but designed to improve upon the safety profile while maintaining the efficacy of sunitinib. By targeting the VEGF and PDGF receptors, X‐82 was expected to disrupt tumor angiogenesis and be active in a broad spectrum of solid tumors. Therefore, we determined the maximum tolerated dose (MTD) and characterized the preliminary pharmacokinetics and clinical tumor response of X‐82 as a single agent in patients with advanced solid tumors.

Methods.

Adult patients with advanced solid tumors received X‐82 as tablets or capsules (once daily [q.d.] or b.i.d.) every 4 weeks. Patients were evaluated for response every 8 weeks, and continued treatment until disease progression or intolerable toxicity.

Results.

Fifty‐two patients received study treatment in 17 cohorts. X‐82 capsule dosing was as follows: cohorts 1–6 (20–400 mg q.d.) and cohorts 7–8 (140–200 mg b.i.d.). Patients in cohorts 9–17 received 50–800 mg q.d. tablet dosing. The median time on treatment was 58 days. X‐82 blood pharmacokinetics appeared dose‐independent with a t_1/2 of 5.13 hours and 6.48 hours for capsule and tablet formulations, respectively. No apparent accumulation was observed after 21 days of daily dosing.

Conclusion.

X‐82 had a safety profile consistent with its mechanism of action. It has a short half‐life and was well tolerated by most patients. Study enrollment ended prior to the determination of the MTD because of the apparent saturation of absorption at 400–800 mg. The recommended dose of X‐82 as a single agent in patients with advanced cancer is 400 mg q.d.

A Phase 1, open-label, multicentre study to compare the capsule and tablet formulations of AZD5363 and explore the effect of food on the pharmacokinetic exposure, safety and tolerability of AZD5363 in patients with advanced solid malignancies: OAK

PURPOSE

AZD5363 is a potent pan-AKT inhibitor originally formulated as a capsule; a tablet was developed for patient convenience and manufacturing ease. This study assessed the PK comparability of both formulations (Part A) and the effect of food (Part B) on the PK/safety of the tablet.

METHODS

Adults with advanced solid tumours received AZD5363 480 mg bid in a partially fasted state by tablet (Week 1) and capsule (Week 2) in a '4-days-on/3-days-off' schedule (Part A). PK parameters were evaluated using pre-defined 90% CIs for AUCτ and Cmax ratios of 0.75-1.33 to assess comparability. In Part B, AZD5363 tablet was given to a new cohort of patients under the same conditions as Part A, except on the morning of PK assessment days, when it was administered after an overnight fast (Week 1) and standard meal (Week 2).

RESULTS

In evaluable patients (N = 11), the geometric least-squares mean ratios (tablet:capsule) for AUCτ and Cmax were 0.90 (0.77-1.06) and 1.02 (0.86-1.20), respectively, demonstrating comparable PK in the partially fasted state. Tablet and capsule safety data were also comparable. Tablet PK profiles indicated later tmax and lower Cmax after food versus overnight fast. Fed and fasted AUCτ and Cmax ratios were 0.89 (0.76-1.05) and 0.67 (0.55-0.82), respectively (N = 9). The safety/tolerability profile of the tablet was comparable between fed and fasted states.

CONCLUSIONS

PK and safety/tolerability of AZD5363 tablet and capsule were comparable. Food did not affect the bioavailability of AZD5363, but reduced the absorption rate without discernibly affecting safety/tolerability.

A Phase I Open-Label Study to Identify a Dosing Regimen of the Pan-AKT Inhibitor AZD5363 for Evaluation in Solid Tumors and in PIK3CA-Mutated Breast and Gynecologic Cancers

Purpose: This phase I, open-label study (Study 1, D3610C00001; NCT01226316) was the first-in-human evaluation of oral AZD5363, a selective pan-AKT inhibitor, in patients with advanced solid malignancies. The objectives were to investigate the safety, tolerability, and pharmacokinetics of AZD5363, define a recommended dosing schedule, and evaluate preliminary clinical activity.Experimental Design: Patients were aged ≥18 years with World Health Organization (WHO) performance status of 0 to 1. Dose escalation was conducted within separate continuous and intermittent [4 days/week (4/7) or 2 days/week (2/7)] schedules with safety, pharmacokinetic, and pharmacodynamic analyses. Expansion cohorts of approximately 20 patients each explored AZD5363 activity in PIK3CA-mutant breast and gynecologic cancers.Results: MTDs were 320, 480, and 640 mg for continuous (n = 47), 4/7 (n = 21), and 2/7 (n = 22) schedules, respectively. Dose-limiting toxicities were rash and diarrhea for continuous, hyperglycemia for 2/7, and none for 4/7. Common adverse events were diarrhea (78%) and nausea (49%) and, for Common Terminology Criteria for Adverse Events grade ≥3 events, hyperglycemia (20%). The recommended phase II dose (480 mg bid, 4/7 intermittent) was assessed in PIK3CA-mutant breast and gynecologic expansion cohorts: 46% and 56% of patients, respectively, showed a reduction in tumor size, with RECIST responses of 4% and 8%. These responses were less than the prespecified 20% response rate; therefore, the criteria to stop further recruitment to the PIK3CA-mutant cohort were met.Conclusions: At the recommended phase II dose, AZD5363 was well tolerated and achieved plasma levels and robust target modulation in tumors. Proof-of-concept responses were observed in patients with PIK3CA-mutant cancers treated with AZD5363. Clin Cancer Res; 24(9); 2050-9. ©2017 AACRSee related commentary by Costa and Bosch, p. 2029.

Anticancer Properties of Halogenated Pyrrolo[3,2-d]pyrimidines with Decreased Toxicity via N5 Substitution

Halogenated pyrrolo[3,2-d]pyrimidine analogues have shown antiproliferative activity in recent studies, with cell accumulation occurring in the G2 /M stage without apoptosis. However, the mechanism of action and pharmacokinetic (PK) profile of these compounds has yet to be determined. To investigate the PK profile of these compounds, a series of halogenated pyrrolo[3,2-d]pyrimidine compounds was synthesized and first tested for activity in various cancer cell lines followed by a mouse model. EC50 values ranged from 0.014 to 14.5 μm, and maximum tolerated doses (MTD) in mice were between 5 and 10 mg kg-1 . This indicates a wide variance in activity and toxicity that necessitates further study. To decrease toxicity, a second series of compounds was synthesized with N5-alkyl substitutions in an effort to slow the rate of metabolism, which was thought to be leading to the toxicity. The N-substituted compounds demonstrated comparable cell line activity (EC50 values between 0.83-7.3 μm) with significantly decreased toxicity (MTD=40 mg kg-1 ). Finally, the PK profile of the active N5-substituted compound shows a plasma half-life of 32.7 minutes, and rapid conversion into the parent unsubstituted analogue. Together, these data indicate that halogenated pyrrolo[3,2-d]pyrimidines present a promising lead into potent antiproliferative agents with tunable activity and toxicity, and rapid metabolism.

[Inhibition of the Janus kinase-signal transducer and activator of transcription is a new treatment modality of rheumatoid arthritis]

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease. The introduction of a new class of disease-modifying anti-rheumatic drugs, which work by inhibiting the Janus kinase-signal transducer and activator of transcription (JAK/STAT) pathway, has led to new possibilities for achieving remission of RA. Tofacitinib and baricitinib are both JAK/STAT inhibitors, which have shown efficacy in line with anti-tumour necrosis factor treatment. The side effects seem manageable, and up to now only increased risk of herpes zoster has raised consideration. JAK/STAT inhibitors create new possibilities for reaching low disease activity or remission for patients with RA.

Chemical template-assisted synthesis of monodisperse rattle-type Fe3O4@C hollow microspheres as drug carrier

A chemical template strategy was put forward to synthesize monodisperse rattle-type magnetic carbon (Fe₃O₄@C) hollow microspheres. During the synthesis procedure, monodisperse Fe₂O₃ microspheres were used as chemical template, which released Fe³⁺ ions in acidic solution and initiated the in-situ polymerization of pyrrole into polypyrrole (PPy) shell. With the continual acidic etching of Fe₂O₃ microspheres, rattle-type Fe₂O₃@PPy microspheres were generated with the cavity appearing between the PPy shell and left Fe₂O₃ core, which were then transformed into Fe₃O₄@C hollow microspheres through calcination in nitrogen atmosphere. Compared with traditional physical template, the shell and cavity of rattle-type hollow microspheres were generated in one step using the chemical template method, which obviously saved the complex procedures including the coating and removal of middle shells. The experimental results exhibited that the rattle-type Fe₃O₄@C hollow microspheres with different parameters could be regulated through controlled synthesis of the intermediate Fe₂O₃@PPy product. Moreover, when the rattle-type Fe₃O₄@C hollow microspheres were investigated as drug carrier, they manifested sustained-release behaviour of doxorubicin, justifying their promising applications as carriers in drug delivery.

STATEMENT OF SIGNIFICANCE

The aim of the present study was first to synthesize rattle-type Fe₃O₄@C hollow microspheres through a simple synthesis method as a drug carrier. Here a chemical template synthesis of rattle-type hollow microspheres was developed, which saved the complex procedures including the coating and removal of middle shells in traditional physical template. Second, all the influence factors in the reaction processes were systematically investigated to obtain rattle-type Fe₃O₄@C hollow microspheres with controlled parameters. Third, the rattle-type Fe₃O₄@C hollow microspheres were studied as drug carriers and the influences of their structural parameters on drug loading and releasing performance were investigated.

Application of Physiologically-Based Pharmacokinetic Modeling for the Prediction of Tofacitinib Exposure in Japanese

Tofacitinib (3-[(3R,4R)-4-methyl-3-[methyl(7H-pyrrolo[2,3-d]pyrimidin-4-yl)amino]piperidin-1-yl]-3 -oxopropanenitrile) is an oral Janus kinase inhibitor that is approved in countries including Japan and the United States for the treatment of rheumatoid arthritis, and is being developed across the globe for the treatment of inflammatory diseases. In the present study, a physiologically-based pharmacokinetic model was applied to compare the pharmacokinetics of tofacitinib in Japanese and Caucasians to assess the potential impact of ethnicity on the dosing regimen in the two populations. Simulated plasma concentration profiles and pharmacokinetic parameters, i.e. maximum concentration and area under plasma concentration-time curve, in Japanese and Caucasian populations after single or multiple doses of 1 to 30 mg tofacitinib were in agreement with clinically observed data. The similarity in simulated exposure between Japanese and Caucasian populations supports the currently approved dosing regimen in Japan and the United States, where there is no recommendation for dose adjustment according to race. Simulated results for single (1 to 100 mg) or multiple doses (5 mg twice daily) of tofacitinib in extensive and poor metabolizers of CYP2C19, an enzyme which has been shown to contribute in part to tofacitinib elimination and is known to exhibit higher frequency in Japanese compared to Caucasians, were also in support of no recommendation for dose adjustment in CYP2C19 poor metabolizers. This study demonstrated a successful application of physiologically-based pharmacokinetic modeling in evaluating ethnic sensitivity in pharmacokinetics at early stages of development, presenting its potential value as an efficient and scientific method for optimal dose setting in the Japanese population.

Tofacitinib as Induction and Maintenance Therapy for Ulcerative Colitis

BACKGROUND

Tofacitinib, an oral, small-molecule Janus kinase inhibitor, was shown to have potential efficacy as induction therapy for ulcerative colitis in a phase 2 trial. We further evaluated the efficacy of tofacitinib as induction and maintenance therapy.

METHODS

We conducted three phase 3, randomized, double-blind, placebo-controlled trials of tofacitinib therapy in adults with ulcerative colitis. In the OCTAVE Induction 1 and 2 trials, 598 and 541 patients, respectively, who had moderately to severely active ulcerative colitis despite previous conventional therapy or therapy with a tumor necrosis factor antagonist were randomly assigned to receive induction therapy with tofacitinib (10 mg twice daily) or placebo for 8 weeks. The primary end point was remission at 8 weeks. In the OCTAVE Sustain trial, 593 patients who had a clinical response to induction therapy were randomly assigned to receive maintenance therapy with tofacitinib (either 5 mg or 10 mg twice daily) or placebo for 52 weeks. The primary end point was remission at 52 weeks.

RESULTS

In the OCTAVE Induction 1 trial, remission at 8 weeks occurred in 18.5% of the patients in the tofacitinib group versus 8.2% in the placebo group (P=0.007); in the OCTAVE Induction 2 trial, remission occurred in 16.6% versus 3.6% (P<0.001). In the OCTAVE Sustain trial, remission at 52 weeks occurred in 34.3% of the patients in the 5-mg tofacitinib group and 40.6% in the 10-mg tofacitinib group versus 11.1% in the placebo group (P<0.001 for both comparisons with placebo). In the OCTAVE Induction 1 and 2 trials, the rates of overall infection and serious infection were higher with tofacitinib than with placebo. In the OCTAVE Sustain trial, the rate of serious infection was similar across the three treatment groups, and the rates of overall infection and herpes zoster infection were higher with tofacitinib than with placebo. Across all three trials, adjudicated nonmelanoma skin cancer occurred in five patients who received tofacitinib and in one who received placebo, and adjudicated cardiovascular events occurred in five who received tofacitinib and in none who received placebo; as compared with placebo, tofacitinib was associated with increased lipid levels.

CONCLUSIONS

In patients with moderately to severely active ulcerative colitis, tofacitinib was more effective as induction and maintenance therapy than placebo. (Funded by Pfizer; OCTAVE Induction 1, OCTAVE Induction 2, and OCTAVE Sustain ClinicalTrials.gov numbers, NCT01465763 , NCT01458951 , and NCT01458574 , respectively.).

Effect of Therapeutic and Supratherapeutic Doses of Vonoprazan on the QT/QTc Interval in a Phase I Randomized Study in Healthy Subjects

This phase I, randomized, 4-period, 4-sequence, double-blind, active- and placebo-controlled, crossover study assessed the effects of vonoprazan on the QT/QTc interval in healthy subjects. Subjects received single oral doses of vonoprazan 40 mg, vonoprazan 120 mg, moxifloxacin 400 mg (positive control/open label), and placebo. The primary end point was time-matched, placebo-corrected, baseline-adjusted mean Fridericia-corrected QT interval (ddQTcF). Of 64 subjects (mean age, 37.8 years; 50% male), 63 received all four regimens. One subject discontinued due to nondrug-related adverse event of tonsillitis. Assay sensitivity was established; lower bound of the one-sided 95% confidence interval (CI) for ddQTcF was >5 ms between 1.5 and 12 h following moxifloxacin administration. For both doses of vonoprazan, the one-sided upper 95% CI ddQTcF did not exceed 10 ms. There was no correlation between plasma vonoprazan concentrations and increases in ddQTcF. Vonoprazan was well tolerated. No severe adverse events/deaths were reported. (European Clinical Trials Database Registry: 2011-004003-20.).

In vitro biologic efficacy of sunitinib drug-eluting beads on human colorectal and hepatocellular carcinoma-A pilot study

Purpose

Sunitinib drug eluting beads (DEB) are a novel anti-angiogenic bead preparation for use in transarterial chemoembolization. However, systematic studies of sunitinib DEB’s effect on cancer cells have not been reported. Herein, we assess their direct biologic efficacy against carcinoma cell lines and correlate cell viability with drug release in vitro.

Materials and methods

Sunitinib-HCl (10mg/mL) in Milli-Q water was mixed with LC Bead® 300–500μm (Biocompatibles UK Ltd.). Loading and release were assessed by measurement of drug UV absorbance using UV-visible spectrophotometer. Viability of human colorectal cancer (CRC, HCT116 and HT29) and hepatocellular carcinoma (HCC, HepG2) cells upon exposure to sunitinib DEB was measured using a bioluminescent assay. Drug concentration during exposure was quantified using HPLC.

Results

When added to cultured HepG2 cells, sunitinib DEB rapidly inhibited viability with a significant decrease observed within 1 hour of incubation. Viability of HCT116 and HT29 cells decreased relatively slower, with significant reductions observed after 8 and 24 hours, respectively. After 24 hours there was nearly complete inhibition of all three cell lines. There was no difference in viability observed between cells treated with 5 μl, 10 μL, or 20 μL of sunitinib DEB. HPLC analysis of the cell culture supernatant demonstrated saturation of the cell medium within approximately 4 hours for each amount added, with sunitinib achieving a final concentration of 17.61 μM (SE ±1.01).

Conclusions

Sunitinib can be efficiently loaded to and released from LC beads, and the resulting sunitinib DEB demonstrate strong in vitro inhibition of human CRC and HCC cells.

Chemical Structure and Concentration of Intratumor Catabolites Determine Efficacy of Antibody Drug Conjugates

Despite recent technological advances in quantifying antibody drug conjugate (ADC) species, such as total antibody, conjugated antibody, conjugated drug, and payload drug in circulation, the correlation of their exposures with the efficacy of ADC outcomes in vivo remains challenging. Here, the chemical structures and concentrations of intratumor catabolites were investigated to better understand the drivers of ADC in vivo efficacy. Anti-CD22 disulfide-linked pyrrolobenzodiazepine (PBD-dimer) conjugates containing methyl- and cyclobutyl-substituted disulfide linkers exhibited strong efficacy in a WSU-DLCL2 xenograft mouse model, whereas an ADC derived from a cyclopropyl linker was inactive. Total ADC antibody concentrations and drug-to-antibody ratios (DAR) in circulation were similar between the cyclobutyl-containing ADC and the cyclopropyl-containing ADC; however, the former afforded the release of the PBD-dimer payload in the tumor, but the latter only generated a nonimmolating thiol-containing catabolite that did not bind to DNA. These results suggest that intratumor catabolite analysis rather than systemic pharmacokinetic analysis may be used to better explain and predict ADC in vivo efficacy. These are good examples to demonstrate that the chemical nature and concentration of intratumor catabolites depend on the linker type used for drug conjugation, and the potency of the released drug moiety ultimately determines the ADC in vivo efficacy.

Discovery and characterization of a novel series of N-phenylsulfonyl-1H-pyrrole picolinamides as positive allosteric modulators of the metabotropic glutamate receptor 4 (mGlu4)

Herein we report the synthesis and characterization of a novel series of N-phenylsulfonyl-1H-pyrrole picolinamides as novel positive allosteric modulators of mGlu4. We detail our work towards finding phenyl replacements for the core scaffold of previously reported phenyl sulfonamides and phenyl sulfone compounds. Our efforts culminated in the identification of N-(1-((3,4-dimethylphenyl)sulfonyl)-1H-pyrrol-3-yl)picolinamide as a potent PAM of mGlu4.

Sunitinib (Sutent®): A novel agent for the treatment of metastatic renal cell carcinoma

Objective. To provide a review of the clinical data supporting the use of sunitinib (Sutent®), a multitargeted, small molecule, tyrosine kinase inhibitor, with focus on its approved indication for the treatment of advanced renal cell carcinoma in patients with metastatic disease requiring drug therapy.Data sources. A MEDLINE search of the medical literature was conducted using the terms ‘sunitinib’ and ‘SU11248’. References from the articles were reviewed and relevant sources were included. Data summary. The introduction of dual tyrosine kinase receptor inhibitors is a novel approach to treating advanced metastatic renal cell carcinoma (mRCC) by preventing angiogenesis and tumor growth. Based on its ability to inhibit several targets involved in angiogenesis and endothelial cell proliferation, sunitinib offers patients with mRCC an alternative for treatment. A recent Phase III study evaluating sunitinib as first-line therapy showed a significant difference when compared to interferonalfa (IFN-α) for a progression-free survival of 11 months in the sunitinib arm and 5 months in the IFN-α arm (hazard ratio 0.42; 95% CI 0.32–0.54; P50.001). Two Phase II trials determined sunitinib was effective as second-line therapy in mRCC patients who failed previous cytokine treatment. Partial response rates were 40% (95% CI 28%–53%) and 34% (95% CI 25%–44%). Multiple ongoing trials are currently underway to evaluate sunitinib for first-line therapy in mRCC. J Oncol Pharm Practice (2007) 13: 5–16.

Pharmacological characterization of CRTh2 antagonist LAS191859: Long receptor residence time translates into long-lasting in vivo efficacy

The chemoattractant receptor-homologous molecule expressed on T-helper type 2 cells (CRTh2) is a G protein-coupled receptor expressed on the leukocytes most closely associated with asthma and allergy like eosinophils, mast cells, Th2-lymphocytes and basophils. At present it is clear that CRTh2 mediates most prostaglandin D2 (PGD2) pro-inflammatory effects and as a result antagonists for this receptor have reached asthma clinical studies showing a trend of lung function improvement. The challenge remains to identify compounds with improved clinical efficacy when administered once a day. Herein we described the pharmacological profile of LAS191859, a novel, potent and selective CRTh2 antagonist. In vitro evidence in GTPγS binding studies indicate that LAS191859 is a CRTh2 antagonist with activity in the low nanomolar range. This potency is also maintained in cellular assays performed with human eosinophils and whole blood. The main differentiation of LAS191859 vs other CRTh2 antagonists is in its receptor binding kinetics. LAS191859 has a residence time half-life of 21h at CRTh2 that translates into a long-lasting in vivo efficacy that is independent of plasma levels. We believe that the strategy behind this compound will allow optimal efficacy and posology for chronic asthma treatment.

Monte Carlo simulations of the clinical benefits from therapeutic drug monitoring of sunitinib in patients with gastrointestinal stromal tumours

PURPOSE

Therapeutic drug monitoring (TDM) is being considered as a tool to individualise sunitinib treatment of gastrointestinal stromal tumours (GIST). Here, we used computer simulations to assess the expected impact of sunitinib TDM on the clinical outcome of patients with GIST.

METHODS

Monte Carlo simulations were performed in R, based on previously published pharmacokinetic-pharmacodynamic models. Clinical trials with dose-limiting toxicity and patient dropout were simulated to establish the study size required to obtain sufficient statistical power for comparison of TDM-guided and fixed dosing.

RESULTS

The simulations revealed that TDM might increase time to tumour progression by about 1-2 months (15-31 %) in eligible patients. However, the number of subjects required for a sufficient statistical power to quantify clinical benefit of TDM guided is likely to be prohibitively high (>1000).

CONCLUSION

Although data from randomised clinical trials on the clinical impact of sunitinib TDM are lacking, our findings support implementation of sunitinib TDM in clinical practice. For rare cancers with well-defined exposure-response relationships, modelling and simulation might allow the optimisation of dosing strategies when clinical trials cannot be performed due to low number of patients.

Phase I Clinical Trial of Marizomib (NPI-0052) in Patients with Advanced Malignancies Including Multiple Myeloma: Study NPI-0052-102 Final Results

PURPOSE

Marizomib (NPI-0052) is an irreversible proteasome inhibitor, derived from a marine actinomycete, with activity and specificity that is distinct from other proteasome inhibitors.

EXPERIMENTAL DESIGN

Phase I study (NPI-0052-102) evaluated the MTD, pharmacokinetics, and pharmacodynamics of marizomib intravenously on two dosing schedules.

RESULTS

Forty-two patients with advanced malignancies received Schedule A (0.1-0.9 mg/m(2) over 1-10 minutes on days 1, 8, 15 in 4-week cycles); 44 patients with relapsed and/or refractory multiple myeloma (RRMM) and other hematologic malignancies received Schedule B (0.075-0.6 mg/m(2) over 1 minute to 2 hours on days 1, 4, 8, 11, in 3-week cycles). The Schedule A recommended phase II dose was 0.7 mg/m(2) over 10 minutes; Schedule B was 0.5 mg/m(2) over 2 hours. The most common (>25% of patients) related adverse events were fatigue, nausea, diarrhea, and infusion site pain (Schedule A); and fatigue (Schedule B). Overall response rate of 11% was seen in 27 efficacy-evaluable RRMM Schedule B patients (1 very good partial response, 3 partial responses, 4 minimal responses, and 12 stable disease). One Schedule A patient with transformed marginal zone lymphoma had complete response. Marizomib has a short half-life (<30 minutes), with high volume of distribution (∼15-416 L) and clearance (∼0.9-22 L/minutes).

CONCLUSIONS

Marizomib does not exhibit the severe peripheral neuropathy or hematologic toxicity observed with other proteasome inhibitors. Marizomib was generally well tolerated with low-dose dexamethasone, demonstrated activity in heavily pretreated RRMM patients, and warrants further evaluation. Clin Cancer Res; 22(18); 4559-66. ©2016 AACR.

Association Study of a Functional Variant on ABCG2 Gene with Sunitinib-Induced Severe Adverse Drug Reaction

Sunitinib is a tyrosine kinase inhibitor and used as the first-line treatment for advanced renal cell carcinoma (RCC). Nevertheless, inter-individual variability of drug's toxicity was often observed among patients who received sunitinib treatment. This study is to investigate the association of a functional germline variant on ABCG2 that affects the pharmacokinetics of sunitinib with sunitinib-induced toxicity of RCC patients in the Japanese population. A total of 219 RCC patients were recruited to this pharmacogenetic study. ABCG2 421C>A (Q141K) was genotyped by using PCR-Invader assay. The associations of both clinical and genetic variables were evaluated with logistic regression analysis and subsequently receiver operating characteristic (ROC) curve was plotted. About 43% (92/216) of RCC patients that received sunitinib treatment developed severe grade 3 or grade 4 thrombocytopenia according to the National Cancer Institute-Common Terminology Criteria for Adverse Events version 3.0, the most common sunitinib-induced adverse reaction in this study. In the univariate analysis, both age (P = 7.77x10(-3), odds ratio (OR) = 1.04, 95%CI = 1.01-1.07) and ABCG2 421C>A (P = 1.87x10(-2), OR = 1.71, 95%CI = 1.09-2.68) showed association with sunitinib-induced severe thrombocytopenia. Multivariate analysis indicated that the variant ABCG2 421C>A is suggestively associated with severe thrombocytopenia (P = 8.41x10(-3), OR = 1.86, 95% CI = 1.17-2.94) after adjustment of age as a confounding factor. The area under curve (AUC) of the risk prediction model that utilized age and ABCG2 421C>A was 0.648 with sensitivity of 0.859 and specificity of 0.415. Severe thrombocytopenia is the most common adverse reaction of sunitinib treatment in Japanese RCC patients. ABCG2 421C>A could explain part of the inter-individual variability of sunitinib-induced severe thrombocytopenia.

The influence of the time-of-day administration of sunitinib on the penetration through the blood-brain and blood-aqueous humour barriers in rabbits

OBJECTIVE

Sunitinib is a multiple tyrosine kinase inhibitor (TKI) that exerts anti-tumor and antiangiogenic activity. It is used for the treatment of metastatic gastrointestinal stromal tumours, renal cell carcinoma and pancreatic neuroendocrine tumours. A few studies confirm the anti-tumour activity of sunitinib in brain tumours and uveal melanoma, as well as its efficacy in the reduction of brain metastases of some primary cancers. Therefore, the penetration of sunitinib through the blood-brain barrier (BBB) and blood-aqueous humour barrier (BAB) is an issue of growing interest. The aim of the study was to investigate the influence of the time-of-day administration on the penetration of sunitinib into the cerebrospinal fluid (CSF) and aqueous humour (AH).

MATERIALS AND METHODS

The rabbits were divided into two groups: I (control group)--receiving sunitinib at 8 a.m., and II--receiving sunitinib at 8 p.m. Sunitinib was administered p.o. at a single dose of 25 mg. The concentrations of sunitinib and its active metabolite (SU12662) in the plasma, CSF, AH were measured with the validated HPLC-UV method.

RESULTS

The plasma AUC0-t for sunitinib in group I was 2051.8 ng × h/mL, whereas in group II it was 3069.3 ng × h/mL. The aqueous humour AUC0-t for sunitinib in thr groups were 43.2 and 76.3 ng × h/mL, respectively. The cerebrospinal AUC0-t for sunitinib in groups I and II were 55.5 and 66.3 ng × h/mL, respectively.

CONCLUSIONS

After the evening administration (8 p.m.) the exposure to sunitinib in the rabbits' plasma, AH and CSF was higher than after the morning administration (8 a.m.), but the degree of sunitinib penetration through the BAB and BBB was very low (< 5%) and comparable in both groups.

Elucidating the Mechanism of Tofacitinib Oxidative Decyanation

BACKGROUND

Tofacitinib is known to generate two metabolites M2 (alcohol) and M4 (acid), which are formed as the result of oxidation and loss of the nitrile [1].

METHOD

Systematic in vitro investigation into generation of M2 and M4 from tofacitinib.

RESULTS

In vitro using human liver microsomes, we found a new geminal diol metabolite of tofacitinib (MX) that lost the nitrile. MX was further reduced or oxidized to M2 (alcohol) and M4 (acid), respectively by enzymes such as aldo-keto reductase 1C1, aldehyde oxidase and possibly CYP3A4. Stable label studies using H2 18O and D2O suggested the source of oxygen was from water in the media. This was due to rapid water exchange with MX in the media prior to reduction to M2. In case of deuterium, one was incorporated in M2 and this was mainly as a result of tofacitinib rapid exchange of two deuterium atoms from D2O onto methylene position. After formation of MX, there was one deuterium that no longer exchanged with water and therefore retained in M2 for further reduction.

CONCLUSION

The proposed mechanism involved the initial oxidation by P450 at the α-carbon to the nitrile group generating an unstable cyanohydrin intermediate; followed by the loss of the nitrile group to form a new geminal diol metabolite (MX).

Structure-Guided Blockade of CSF1R Kinase in Tenosynovial Giant-Cell Tumor

BACKGROUND

Expression of the colony-stimulating factor 1 (CSF1) gene is elevated in most tenosynovial giant-cell tumors. This observation has led to the discovery and clinical development of therapy targeting the CSF1 receptor (CSF1R).

METHODS

Using x-ray co-crystallography to guide our drug-discovery research, we generated a potent, selective CSF1R inhibitor, PLX3397, that traps the kinase in the autoinhibited conformation. We then conducted a multicenter, phase 1 trial in two parts to analyze this compound. In the first part, we evaluated escalations in the dose of PLX3397 that was administered orally in patients with solid tumors (dose-escalation study). In the second part, we evaluated PLX3397 at the chosen phase 2 dose in an extension cohort of patients with tenosynovial giant-cell tumors (extension study). Pharmacokinetic and tumor responses in the enrolled patients were assessed, and CSF1 in situ hybridization was performed to confirm the mechanism of action of PLX3397 and that the pattern of CSF1 expression was consistent with the pathological features of tenosynovial giant-cell tumor.

RESULTS

A total of 41 patients were enrolled in the dose-escalation study, and an additional 23 patients were enrolled in the extension study. The chosen phase 2 dose of PLX3397 was 1000 mg per day. In the extension study, 12 patients with tenosynovial giant-cell tumors had a partial response and 7 patients had stable disease. Responses usually occurred within the first 4 months of treatment, and the median duration of response exceeded 8 months. The most common adverse events included fatigue, change in hair color, nausea, dysgeusia, and periorbital edema; adverse events rarely led to discontinuation of treatment.

CONCLUSIONS

Treatment of tenosynovial giant-cell tumors with PLX3397 resulted in a prolonged regression in tumor volume in most patients. (Funded by Plexxikon; ClinicalTrials.gov number, NCT01004861.).

An effective approach to reduce inflammation and stenosis in carotid artery: polypyrrole nanoparticle-based photothermal therapy

Photothermal therapy (PTT), as a promising treatment for tumours, has rarely been reported for application in artery restenosis, which is a common complication of endovascular management due to enduring chronic inflammation and abnormal cell proliferation. In our study, biodegradable polypyrrole nanoparticles (PPy-NPs) were synthesized and characterized, including their size distribution, UV-vis-NIR absorbance, molar extinction coefficients, and photothermal properties. We then verified that PPy-NP incubation followed by 915 nm near-infrared (NIR) laser irradiation could effectively ablate inflammatory macrophages in vitro, leading to significant cell apoptosis and cell death. Further, it was found that a combination of local PPy-NP injection with 915 nm NIR laser irradiation could significantly alleviate arterial inflammation by eliminating infiltrating macrophages and further ameliorating artery stenosis in an ApoE(-/-) mouse model, without showing any obvious toxic side effects. Thus, we propose that PTT based on PPy-NPs as photothermal agents and a 915 nm NIR laser as a power source can serve as a new effective treatment for reducing inflammation and stenosis formation in inflamed arteries after endovascular management.

Effect of concomitant icosapent ethyl (eicosapentaenoic acid ethyl ester) on the pharmacokinetics of atorvastatin

BACKGROUND AND OBJECTIVE

Icosapent ethyl is a high-purity prescription form of eicosapentaenoic acid ethyl ester approved as an adjunct to diet to reduce triglyceride levels in adult patients with triglyceride levels ≥500 mg/dL (≥5.65 mmol/L). The objective of this open-label, drug-drug interaction study was to examine the effects of icosapent ethyl on the steady-state pharmacokinetics of atorvastatin, a commonly prescribed medication in patients with dyslipidaemia.

METHODS

Thirty healthy subjects received atorvastatin 80 mg/day on days 1-7, icosapent ethyl 4 g/day on days 8-28, and co-administration on days 29-35. Primary end-points were natural log-transformed maximum plasma concentration (C(max)) and area under the concentration-versus-time curve from 0 to 24 h (AUC(0-24)) for atorvastatin, 2-hydroxyatorvastatin, and 4-hydroxyatorvastatin with and without icosapent ethyl.

RESULTS

Of the 30 subjects enrolled, 26 completed the study. The 90% confidence intervals for C(max) and AUC(0-24) least-squares geometric mean ratios were within the 0.80-1.25 bounds. Concomitant administration of icosapent ethyl and atorvastatin was safe and well tolerated and icosapent ethyl did not significantly change the steady state C(max) and AUC(0-24) of atorvastatin, 2-hydroxyatorvastatin, or 4-hydroxyatorvastatin.

CONCLUSIONS

At steady-state concentrations, icosapent ethyl did not have an effect on the pharmacokinetics of atorvastatin. Co-administration of icosapent ethyl and atorvastatin was safe and well tolerated in healthy adult subjects.

[Choosing wisely when prescribing statins]

The Dutch campaign 'Verstandig kiezen', based on the American programme 'Choosing wisely', aims to improve quality in healthcare, with attention to cost control. The 'Choosing wisely'-based programme can be applied in the choice of a statin. Atorvastatin and rosuvastatin are regarded as equal choices in various guidelines regarding cardiovascular risk management. Generic atorvastatin is available, and is approximately 25 times cheaper than rosuvastatin in almost equipotent doses. Rosuvastatin provides a greater LDL reduction than atorvastatin. Patient LDL targets can usually be achieved with atorvastatin, and rosuvastatin is not needed. At group level, there are no relevant differences in adverse-events profile between both statins. Atorvastatin and rosuvastatin do have different pharmacokinetic interactions. When changing medication, good provision of information is a prerequisite for patient satisfaction and compliance. We advise use of atorvastatin instead of rosuvastatin as drug of choice when the LDL target is not reached using simvastatin. However, under specific conditions, rosuvastatin should be the treatment of choice. Efficacy and adverse effects should then be evaluated at individual patient level.