Nelfinavir suspension obtained from nelfinavir tablets has equivalent pharmacokinetic profile.

The pharmacokinetics of nelfinavir tablets (A) and an oral simplified nelfinavir suspension (B) were studied. Twelve healthy volunteers randomly received either five 250-mg nelfinavir tablets or a simplified oral suspension obtained from tablets dissolved in water (nelfinavir 1250 mg in 100 mL of water) in a single dose before being crossed over to the second treatment after a one-week washout period. Blood samples were drawn up to 24 h after drug administration. Nelfinavir concentrations in plasma were analyzed by a specific and validated reverse-phase high-performance liquid chromatography assay (HPLC) with UV detection, and pharmacokinetic values were determined. For the AUC(0-infinity) with means+/-SD of 31.71+/-7.85, 30.88+/-10.28 (microg/L) respectively for treatments B and A, the ratio (F(B/A)) was of 1.1 with a C.I. of 0.90-1.24. For Cmax with means+/-SD of 3.1+/-0.6 (treatment B) and 3.2+/-0.8 mg/mL (treatment A), the ratio was 1.0. with C.I. of 0.92-1.08. The two treatments evidenced no significant differences in AUC(0-inifnity) and Cmax values and the two-one sided t-test showed that the two preparations are bioequivalent. There was no significant difference in Tmax between the liquid and tablets. Nelfinavir suspension might be a option for treating HIV-infected patients with swallowing disturbances or compliance problems.     

Nelfinavir induces radiation sensitization in pituitary adenoma cells

Pituitary adenomas with local invasion and high secretory activity remain a therapeutic challenge. The HIV protease inhibitor nelfinavir is a radiosensitizer in multiple tumor models. We tested nelfinavir as a radiosensitizer in pituitary adenoma cells in vitro and in vivo. We examined the effect of nelfinavir with radiation on in vitro cell viability, clonogenic survival, apoptosis, prolactin secretion, cell cycle distribution, and the PI3K-AKT-mTOR pathway. We evaluated tumor growth delay and confirmed nelfinavir's effect on the PI3K-AKT-mTOR pathway in a hind-flank model. Nelfinavir sensitized pituitary adenoma cells to ionizing radiation as shown by viability assays and clonogenic assay with an enhancement ratio of 1.2 (p < 0.05). There is increased apoptotic cell death, as determined by annexin-V expression and cleaved caspase-3 levels. Nelfinavir does not affect prolactin secretion or cell cycle distribution. In vivo, untreated tumors reached 4-fold volume in 12 days, 17 days with nelfinavir treatment, 27 days with radiation 6 Gy, and 41 days with nelfinavir plus radiation (one-way ANOVA p < 0.001). Decreased phospho-S6 on Western blotting in vitro and immunohistochemistry in vivo demonstrated nelfinavir inhibition of the PI3K-AKT-mTOR pathway. Our data suggests a promising combination therapy with nelfinavir plus radiation in pituitary adenomas, which should be investigated in clinical studies.     

Nelfinavir augments proteasome inhibition by bortezomib in myeloma cells and overcomes bortezomib and carfilzomib resistance

HIV protease inhibitors (HIV-PI) are oral drugs for HIV treatment. HIV-PI have antitumor activity via induction of ER-stress, inhibition of phospho-AKT (p-AKT) and the proteasome, suggesting antimyeloma activity. We characterize the effects of all approved HIV-PI on myeloma cells. HIV-PI were compared regarding cytotoxicity, proteasome activity, ER-stress induction and AKT phosphorylation using myeloma cells in vitro. Nelfinavir is the HIV-PI with highest cytotoxic activity against primary myeloma cells and with an IC₅₀ near therapeutic drug blood levels (8–14 μM), irrespective of bortezomib sensitivity. Only nelfinavir inhibited intracellular proteasome activity in situ at drug concentrations <40 μℳ. Ritonavir, saquinavir and lopinavir inhibited p-AKT comparable to nelfinavir, and showed similar synergistic cytotoxicity with bortezomib against bortezomib-sensitive cells. Nelfinavir had superior synergistic activity with bortezomib/carfilzomib in particular against bortezomib/carfilzomib-resistant myeloma cells. It inhibited not only the proteasomal β1/β5 active sites, similar to bortezomib/carfilzomib, but in addition the β2 proteasome activity not targeted by bortezomib/carfilzomib. Additional inhibition of β2 proteasome activity is known to sensitize cells for bortezomib and carfilzomib. Nelfinavir has unique proteasome inhibiting activity in particular on the bortezomib/carfilzomib-insensitive tryptic (β2) proteasome activity in intact myeloma cells, and is active against bortezomib/carfilzomib-resistant myeloma cells in vitro.     

Pharmacokinetics of orally administered ABT-751 in children with neuroblastoma and other solid tumors

Purpose

To describe the pharmacokinetics of orally administered ABT-751 and its conjugated metabolites in children with neuroblastoma and other solid tumors and to relate pharmacokinetic parameters to toxicity and therapeutic outcomes.

Methods

Patients (median age, 11 years) with neuroblastoma (n = 37) or other solid tumors (n = 25) had pharmacokinetic sampling after the first dose of ABT-751 (75–250 mg/m²/day) on a 7-day or 21-day schedule. ABT-751 and its glucuronide and sulfate metabolites were quantified with an HPLC/MS/MS assay. Pharmacokinetic parameters were derived with non-compartmental methods. The relative bioavailability of more water soluble capsule and suspension formulations was assessed.

Results

ABT-751 peaked in plasma at 2 h and declined monoexponentially with a t _1/2 of 5.1 h. The apparent clearance was 33 ml/min/m² and was age-independent. The AUC_0–∞ increased in proportion to the dose, and at 200 mg/m² the median AUC_0–∞ was 91 mcg h/ml and the C _ave was 3.9 mcg/ml. Inter-and intra-patient variability was low. The metabolites were detected in plasma 30 min post-dose and peaked 3–5 h after the dose. The glucuronide:sulfate molar AUC_0–∞ ratio was 0.57. Less than 1% of the dose was excreted in urine as parent drug; 13% of the dose was excreted as sulfate metabolite and 10% as glucuronide metabolite. The relative bioavailability of the water soluble capsule and suspension formulations was 105 and 93%, respectively. AUC_0–∞ was higher in patients experiencing dose-limiting toxicity.

Conclusions

Oral ABT-751 pharmacokinetics was dose-proportional and age-independent with minimal intra- and inter-patient variability in children.     

Comparative Safety,Bioavailability, and Pharmacokinetics of Oral Dexamethasone, 4-mg and 20-mg Tablets,in Healthy Volunteers Under Fasting and Fed Conditions: A Randomized Open-label, 3-way Crossover Study

BackgroundGlucocorticoids, particularly dexamethasone, are often used in combination with novel agents in multiple myeloma. This study compared the safety, rate, and extent of absorption of a single dose of an orally administered 20-mg dexamethasone tablet to five 4-mg tablets (total, 20 mg).Patients and MethodsThis was a single-center, open-label, randomized, 3-way crossover comparative study. Thirty-six volunteers received at least 1 dose of either a single 20-mg dexamethasone tablet, under fasting or fed conditions, or five 4-mg dexamethasone tablets (total, 20 mg). Blood samples were collected before study drug administration and at 21 time points for up to 36 hours after drug administration.ResultsMean area under the concentration-time curve from time zero to the time of last non-zero concentration (AUC_0–t), mean area under the concentration-time curve from time zero to infinity (extrapolated) (AUC_0–∞), and maximum observed concentration (C_max) were 1314.38 ng × h/mL, 1329.24 ng × h/mL, and 257.22 ng/mL, respectively for fasting test formulation (single dexamethasone 20-mg tablet), 1339.74 ng × h/mL, 1358.07 ng × h/mL, and 194.56 ng/mL, respectively, for the fed test formulation (single dexamethasone 20-mg tablet), and 1325.12 ng × h/mL, 1342.12 ng × h/mL, and 244.12 ng/mL, respectively, for the reference formulation (5 dexamethasone 4-mg tablets). The median time of observed C_max was 0.997 hours for the fasting and 2.502 hours for the fed test formulation, compared with 1.495 hours for the reference. Mean plasma elimination half-lives (t_1/2) were 4.0 hours (test fasting), 4.03 hours (test fed), and 3.96 hours (reference). The point estimates and 90% confidence intervals (CIs) for AUC_0-t, AUC_0-∞, and C_max were 99.37% (90% CI, 95.65%-103.24%), 99.24% (90% CI, 95.47%-103.16%), and 106.28% (90% CI, 97.69%-115.62%), respectively, satisfying the bioequivalence criteria of the United States Food and Drug Administration guidelines.ConclusionThe 2 formulations were well-tolerated, and one 20-mg tablet or five 4-mg tablets of dexamethasone are bioequivalent under fasting conditions and thus may be prescribed interchangeably.     

Population pharmacokinetics of peritoneal,plasma ultrafiltrated and protein-bound oxaliplatin concentrations in patients with disseminated peritoneal cancer after intraperitoneal hyperthermic chemoperfusion of oxaliplatin following cytoreductive surgery: correlation between oxaliplatin exposure and thrombocytopenia

Purpose

First, to evaluate the peritoneal (IP), plasma ultrafiltrated (UF) and protein-bound (B) pharmacokinetics (PK) of oxaliplatin after intraperitoneal hyperthermic chemoperfusion (HIPEC) following cytoreductive surgery. Second, to evaluate the relationship between oxaliplatin exposure and observed toxicity.

Methods

IP, UF, and B concentrations from 75 patients treated by 30-min oxaliplatin-based HIPEC procedures were analysed according to a pharmacokinetic modelling approach using NONMEM. Oxaliplatin was administered in a 5 % dextrose solution (2 L/m²) at 360 (n = 58) or 460 mg/m² (n = 17). The most frequently observed toxicities were related to the peritoneal, systemic exposures and to the parameters corresponding to the oxaliplatin absorption from peritoneal cavity into plasma.

Results

IP (n = 536), UF (n = 669) and B (n = 661) concentrations were simultaneously described according to a five-compartment PK model with irreversible nonlinear binding from UF to B according to a Michaelis–Menten equation. The mean (±SD) maximum fraction of dose absorbed and elimination half-life from the peritoneum was 53.7 % (±8.5) and 0.49 h (±0.1), respectively. The mean (±SD) ratio AUC_IP/AUC_UF was 5.3 (±2) confirming the pharmacokinetic advantage of the procedure. Haemoperitoneum (22.7 %), neuropathy (18.7 %), grade 3/4 thrombocytopenia (13.3 %) were the most frequently reported toxicities. AUC_UF accounts for approximately 12 % of the variation in the maximum percentage of platelet decrease (r = 0.35, p = 0.002). Thrombocytopenia was correlated with higher AUC_UF, partly dependent on the extent and rate of oxaliplatin absorption.

Conclusions

Despite a common dose administered, variability in peritoneal and systemic oxaliplatin exposures are observed, leading to differences in haematological toxicity between patients.     

The effect of rifampicin,a prototypical CYP3A4 inducer,on erlotinib pharmacokinetics in healthy subjects

Purpose

Erlotinib, N-(3-ethynylphenyl)-6,7-bis(2-methoxyethoxy) quinazolin-4-amine is approved for the treatment for non-small cell lung cancer and pancreatic cancer. Because erlotinib is metabolized predominately by CYP3A4, co-administration of compounds that increase CYP3A4 activity may alter the efficacy and safety of erlotinib therapy. Two phase I studies were conducted in healthy male subjects to evaluate the effect of pre- or co-administered rifampicin, a CYP3A4 inducer, on the pharmacokinetics of erlotinib.

Methods

Study 1 included Groups A (erlotinib 150 mg days 1 and 15, rifampicin 600 mg days 8–14) and B (erlotinib 150 mg days 1 and 15) in a parallel group study design. Study 2 subjects received erlotinib 150 mg day 1, erlotinib 450 mg day 15, and rifampicin 600 mg days 8–18. The primary endpoint in each study was the ratio of exposure (AUC_0–∞ and C _max) between days 1 and 15. Urinary cortisol metabolic induction ratios were determined in Study 1 for Group A subjects only.

Results

In Study 1, the geometric mean ratios of AUC_0–∞ and C _max were 33 and 71 %, respectively, and the mean cortisol metabolic index increased from 7.4 to 27.0, suggesting cytochrome P450 (CYP) enzyme induction. In Study 2, the geometric mean ratios for AUC_0–∞ and C _max were 19 and 34 % (when dose adjusted from 450 to 150 mg erlotinib), respectively, a greater relative decrease than observed in Study 1.

Conclusions

Erlotinib exposure (AUC_0–∞ and C _max) was reduced after pre- or concomitant dosing with rifampicin. Doses of ≥450 mg erlotinib may be necessary to compensate for concomitant medications with strong CYP3A4 enzyme induction effect.     

Antitumour effects of a protease inhibitor,nelfinavir, in hepatocellular carcinoma cancer cells

Abstract

Nelfinavir is a protease inhibitor with potential antitumour activity against certain cancer types. The objective of this study was to evaluate the antitumour effects of nelfinavir in hepatocellular carcinoma cell lines, HepG2 and WCH-17. Results indicate that nelfinavir inhibited the proliferation of Hep G2 and WCH-17 cell lines, with IC50 of 5·1 and 62·0 μmol/l, respectively. Nelfinavir induced apoptosis in both cell lines, although the extent as indicated by Annexin V staining varied. The concentration of nelfinavir needed to induce apoptosis in liver cancer cells were 10 and 100 μmol/l for HepG2 and WCH-17, respectively. At the same concentrations, nelfinavir induced cell cycle arrest at G0/G1 phase in HepG2 and WCH-17 cell lines. Our results suggest that nelfinavir inhibit hepatoma cell growth, through the induction of apoptosis and cell cycle arrest. However, the clinical relevance of these findings warrants further investigation.     

Evaluation of pharmacokinetics and safety of ponatinib in subjects with chronic hepatic impairment and matched healthy subjects

Purpose

This study evaluated the effects of chronic hepatic impairment on the single-dose pharmacokinetics (PK) of the tyrosine kinase inhibitor ponatinib.

Methods

Subjects (n = 16) had Child-Pugh class A (mild, n = 6), B (moderate, n = 6), or C (severe, n = 4) hepatic impairment and were matched with healthy controls (n = 8). Each subject received a single oral dose of ponatinib 30 mg under fasting conditions, and PK parameters were assessed in blood samples collected through 96 h post-dose.

Results

Ponatinib maximum plasma concentrations (C _max) were observed after 5–6 h in Child-Pugh A, Child-Pugh B, and healthy subjects, and after ~3 h in Child-Pugh C subjects. The estimated  % geometric mean ratios for C _max, area under the plasma concentration–time curves from time zero to last observation (AUC_0–t ) and to infinity (AUC_0–∞) suggested a slightly lower exposure in Child-Pugh B (61.4, 89.1, and 90.6 %, respectively) and Child-Pugh C subjects (62.8, 77.1, and 79.4 %) versus healthy subjects. Child-Pugh A subjects had similar estimated % geometric mean ratio for C _max (106.7 %), and slightly greater estimated % geometric mean ratios for AUC_0–t (133.0 %) and AUC_0–∞ (122.8 %), versus healthy subjects. Mean elimination half-life was extended in subjects with hepatic impairment (43–47 vs 36 h). Ponatinib was generally well tolerated. A single serious AE (pancreatitis) in the Child-Pugh C group resolved with treatment.

Discussion

As no major differences in ponatinib single-dose PK were observed in patients with hepatic impairment versus healthy subjects, a reduction of ponatinib starting dose in these patients is not necessary, but caution is recommended when administering ponatinib to these patients.     

Microdialysis measurement of intratumoral temozolomide concentration after cediranib, a pan-VEGF receptor tyrosine kinase inhibitor, in a U87 glioma model

Background

Combining anti-angiogenesis agents with cytotoxic agents for the treatment of malignant gliomas may affect the cytotoxic drug distribution by normalizing the blood–brain barrier (BBB). This study examines the intratumoral concentration of temozolomide (TMZ) in the presence and absence of the pan-VEGF receptor tyrosine kinase inhibitor, cediranib.

Methods

Seven nude rats bearing U87 intracerebral gliomas had a microdialysis probe centered within the tumor. Ten-days after tumor implantation, TMZ (50 mg/kg) was given orally. The extracellular fluid (ECF) concentrations of TMZ within the tumor were assessed via microdialysis for 6 h following TMZ administration. Cediranib (6 mg/kg) was then given orally, and 12 h later, TMZ was re-administered with subsequent microdialysis collection. A subset of animals also underwent functional MRI to assess angiogenesis in vivo at post-inoculation days 12 and 21, before and after the cediranib treatment.

Results

After dosing of oral TMZ only, ECF-TMZ mean-C _max and area under the concentration curve(AUC_0–∞) within the tumor were 0.59 μg/mL and 1.82 μg h/mL, respectively. Post-cediranib, ECF-TMZ mean-C _max and AUC_0–∞ were 0.83 μg/mL and 3.72 ± 0.61 μg h/mL within the tumor, respectively. This represented a 1.4-fold (p = 0.3) and 2.0-fold (p = 0.06) increase in the ECF-TMZ C _max and AUC_0–∞, respectively, after cediranib administration. In vivo MRI measurements of the various vascular parameters were consistent with a BBB “normalization” profile following cediranib treatment.

Conclusions

In the U87 intracerebral glioma model, within the first day of administration of cediranib, the intratumoral concentrations of TMZ in tumor ECF were slightly, but not statistically significantly, increased when compared to the treatment of TMZ alone with radiographic evidence of a normalized BBB.     

Nelfinavir, A lead HIV protease inhibitor, is a broad-spectrum, anticancer agent that induces endoplasmic reticulum stress, autophagy, and apoptosis in vitro and in vivo.

PURPOSE: The development of new cancer drugs is slow and costly. HIV protease inhibitors are Food and Drug Administration approved for HIV patients. Because these drugs cause toxicities that can be associated with inhibition of Akt, an emerging target in cancer, we assessed the potential of HIV protease inhibitors as anticancer agents. EXPERIMENTAL DESIGN: HIV protease inhibitors were screened in vitro using assays that measure cellular proliferation, apoptotic and nonapoptotic cell death, endoplasmic reticulum (ER) stress, autophagy, and activation of Akt. Nelfinavir was tested in non-small cell lung carcinoma (NSCLC) xenografts with biomarker assessment. RESULTS: Three of six HIV protease inhibitors, nelfinavir, ritonavir, and saquinavir, inhibited proliferation of NSCLC cells, as well as every cell line in the NCI60 cell line panel. Nelfinavir was most potent with a mean 50% growth inhibition of 5.2 micromol/L, a concentration achievable in HIV patients. Nelfinavir caused two types of cell death, caspase-dependent apoptosis and caspase-independent death that was characterized by induction of ER stress and autophagy. Autophagy was protective because an inhibitor of autophagy increased nelfinavir-induced death. Akt was variably inhibited by HIV protease inhibitors, but nelfinavir caused the greatest inhibition of endogenous and growth factor-induced Akt activation. Nelfinavir decreased the viability of a panel of drug-resistant breast cancer cell lines and inhibited the growth of NSCLC xenografts that was associated with induction of ER stress, autophagy, and apoptosis. CONCLUSIONS: Nelfinavir is a lead HIV protease inhibitor with pleiotropic effects in cancer cells. Given its wide spectrum of activity, oral availability, and familiarity of administration, nelfinavir is a Food and Drug Administration-approved drug that could be repositioned as a cancer therapeutic.     

A phase I pharmacokinetics study of 9-nitrocamptothecin in patients with advanced solid tumors

Purpose

9-Nitrocamptothecin (9-NC) is a novel orally administered camptothecin analog. The purpose of this study is to evaluate the pharmacokinetics and safety of 9-nitrocamptothecin in patients with advanced solid tumors.

Methods

The 23 patients for a single-dose pharmacokinetic experiment were divided into 3 dosing cohorts. The dosage of 9-nitrocamptothecin capsule was 1.25, 1.5 and 1.75 mg/m², respectively. The 8 patients for a multiple-dose pharmacokinetic study were orally administered 9-nitrocamptothecin 1.5 mg/m² for 5 consecutive days. Determination of the plasma concentration of 9-nitrocamptothecin was performed by high-performance liquid chromatography-ultraviolet detector technique, and determination of plasma concentration of 9-aminocamptothecin was performed by high-performance liquid chromatography-fluorescence detector technique.

Results

In the single-dose pharmacokinetic study, the mean ± SD 9-nitrocamptothecin C _max were 94.49 ± 41.38, 115.56 ± 63.27 and 147.57 ± 38.19 ng/mL; AUC_0–36 were 877.14 ± 360.90, 961.33 ± 403.58 and 1,189.75 ± 405.80 ng h/mL, respectively; the mean ± SD 9-aminocamptothecin C _max were 12.85 ± 6.46, 10.72 ± 6.58 and 28.74 ± 31.94 ng/mL; AUC_0–36 were 157.61 ± 111.61, 88.71 ± 39.51 and 173.52 ± 122.19 ng h/mL, respectively. In the multiple-dose pharmacokinetic study, the mean ± SD 9-nitrocamptothecin AUC_ss was 907.04 ± 736.47 ng h/mL, C _max was 85.98 ± 47.52 ng/mL, C _min was 18.91 ± 22.50 ng/mL, C _av was 37.79 ± 30.69 ng/mL, DF was 2.16 ± 0.87; the mean ± SD 9-aminocamptothecin AUC_ss was 442.73 ± 308.39 ng h/mL, C _max was 34.83 ± 18.31 ng/mL, C _min was 10.32 ± 6.95 ng/mL, C _av was 18.45 ± 12.85 ng/mL, DF was 1.34 ± 0.42. Comparing single-dose 1.5 mg/m² group with multiple-dose 1.5 mg/m² group, no significant difference was observed in 9-NC pharmacokinetic parameters, but with respect to the metabolite, significant differences were observed in C _max and AUC. The toxicity of 9-NC varied from mild to moderate. No grade 3 or grade 4 toxicity was observed during the study. There was 2- to 13-fold variabilities in 9-NC and 9-AC exposure among different patients for any given dose of 9-NC.

Conclusions

All participants had good tolerance throughout the study. 9-NC and 9-AC exposure did not increase proportionally to the dose ranging from 1.25 to 1.75 mg/m². After 5-day continuous administration, accumulation was observed in the metabolite 9-AC, but not in 9-NC.     

Evaluation of safety, pharmacokinetics, and efficacy of vorinostat, a histone deacetylase inhibitor, in the treatment of gastrointestinal (GI) cancer in a phase I clinical trial

Background

Control of epigenetic changes using histone deacetylase inhibitors (HDACi) is thought to be a promising target in therapy of gastrointestinal (GI) cancer. In this study, we evaluated the safety, pharmacokinetics, and efficacy of two dosing regimens of vorinostat, an oral HDACi, in patients with GI tumors.

Methods

Patients received either vorinostat 300 mg bid for 3 consecutive days followed by 4 rest days per cycle (n = 10) or vorinostat 400 mg qd for 21 consecutive days per cycle (n = 6). Pharmacokinetic parameters were assessed for the first treatment cycle. Efficacy was determined through evaluation of tumors and assessment of treatment response.

Results

The median treatment duration of 300 mg bid was 52.0 days and of 400 mg qd was 51.5 days. The most common drug-related adverse events were anorexia, nausea, fatigue, and hyperglycemia. Two patients taking 400 mg qd had dose-limiting toxicities (DLTs) of thrombocytopenia. No patients taking 300 mg bid experienced DLT. Five patients taking 300 mg bid and 2 patients taking 400 mg qd maintained stable disease for >8 weeks, with the maximum duration of 245 days. Mean drug exposure (±SD) was generally higher with 400 mg qd (area under the curve [AUC_0–∞] of 7.75 ± 2.79 μM h on Day 1 post-dose) compared with 300 mg bid (AUC_0–∞ of 3.94 ± 1.56 μM h on Day 1 post-dose).

Conclusions

Vorinostat 300 mg bid for 3 consecutive days followed by 4 days of rest was better tolerated in patients with GI cancer than a higher once daily dose. Additionally, there were patients in both groups who achieved stable disease, most maintaining it for longer than 8 weeks, suggesting vorinostat as a possible active agent in the treatment of GI cancer.     

Single-Dose Pharmacokinetics of Aztreonam in Healthy Volunteers and Renal Failure Patients

Summary

The pharmacokinetics of aztreonam were studied in 6 healthy male volunteers and 12 male patients with various degrees of chronic renal failure after intravenous bolus injection of 1g of the drug. Serum pharmacokinetics of aztreonam were described by an open, two-compartment kinetic model. The serum levels of aztreonam exceeded the reported minimum inhibitory concentration (MIC)₉₀ for Enterobacteriaceae for 8 hours and up to 24 hours, in healthy volunteers and renal failure patients, respectively. However, the serum levels of the drug exceeded the MIC₅₀ for Pseudomonas aeruginosa for only 4 hours and 12 hours in healthy volunteers and patients, respectively. The half-life of elimination (t 1/2/β) increased significantly (P < 0.001) from 1.8 ± 0.14 h in healthy volunteers and to 4.9 ± 1.1 h in patients with renal failure. The total serum clearance of aztreonam decreased significantly (P< 0.001) from 84.2 ± 7.8 ml/h/kg in healthy volunteers to 30.2 + 9.2 ml/h/kg in patients with renal failure. Á linear correlation (r = 0.971, P< 0.001) was found between creatinine clearance and the total serum clearance of aztreonam. The AUC_0–∞ increased significantly (P< 0.001) from 137.5 ± 12.2 μg/h/ml in healthy volunteers to 464 ± 114.5 μg/h/ml in patients with renal failure.     

The mitochondria-independent cytotoxic effect of nelfinavir on leukemia cells can be enhanced by sorafenib-mediated mcl-1 downregulation and mitochondrial membrane destabilization

Background  

Nelfinavir is an HIV protease inhibitor that has been used for a long period of time to treat HIV-infected individuals. It has recently emerged that nelfinavir could represent a prospective new anti-cancer drug, prompting us to test the effect of nelfinavir on leukemia cells.     

Effects of famotidine or an antacid preparation on the pharmacokinetics of nilotinib in healthy volunteers

Purpose

This study evaluated the effects of either famotidine or antacid on the pharmacokinetics of nilotinib in healthy subjects, with the specific focus to explore different dosing separation schemes leading to a minimized drug–drug interaction.

Methods

Fifty-two subjects were randomized to receive the following treatments in a crossover manner: (A) single oral nilotinib 400 mg alone; (B) famotidine 20 mg twice a day for 3 days, followed by a single administration of nilotinib 400 mg and famotidine 20 mg on Day 4, where famotidine was given 2 h after nilotinib; (C) single oral nilotinib 400 mg and antacid suspension 20 mL, where antacid was given 2 h before nilotinib; (D) single oral nilotinib 400 mg and antacid suspension 20 mL, where antacid was given 2 h after nilotinib.

Results

Comparing Treatment B to Treatment A, the geometric mean ratios of nilotinib C _max, AUC_0-tlast, and AUC_0-inf were 0.966, 0.984, and 0.911, respectively (90 % confidence intervals (CIs), 0.875–1.066, 0.905–1.069, and 0.798–1.039, respectively). Nilotinib pharmacokinetic parameters following Treatment C or Treatment D were similar to those after Treatment A; the corresponding 90 % CIs of the geometric mean ratios of C _max, AUC_0-tlast, and AUC_0-inf all fell within the bioequivalence range of 0.8–1.25.

Conclusions

Neither famotidine nor antacid significantly affected nilotinib pharmacokinetics. When concurrent use of an H2 blocker or an antacid is necessary, the H2 blocker may be administered 10 h before and 2 h after nilotinib dose, or the antacid may be administered 2 h before or 2 h after nilotinib dose.     

Clinical and pharmacokinetic study evaluating the effect of food on the disposition of 9-nitrocamptothecin and its 9-aminocamptothecin metabolite in patients with solid tumors

Background: 9-Nitrocamptothecin (9NC) is an orally administered camptothecin analogue that has completed phase III trials for pancreatic cancer. In biological matrices, camptothecin analogues exist in equilibrium between the active-lactone (LAC) and inactive-hydroxy acid (HA) forms. 9NC has been administered on an empty stomach; however, it is unclear if food alters the absorption and disposition of 9NC and its 9-aminocamptothecin (9AC) active-metabolite. Thus, we evaluated the disposition of 9NC and 9AC after administration of 9NC under fasting conditions and after a standard meal. Methods: Patients were randomized to receive 9NC as a single oral dose at 1.5 mg/m² with 8 ounces (oz) of an acidic beverage under fasting conditions, or after a meal consisting of two eggs, 8 oz of orange juice, buttered toast, 8 oz of milk, and 4 oz of hash brown potatoes. Following a 72 h washout period, 9NC was administered with the alternative condition (i.e., with food or fasting). 9NC was then continued for 5 days of every week. Serial blood samples were obtained prior to and from 0.25 to 24 h after administration of 9NC. The total (sum of LAC + HA) of 9NC and 9AC were measured by an LC-MS/MS assay. Area under the plasma concentration versus time curve (AUC) for 9NC and 9AC total were calculated. After the pharmacokinetic section of the study, patients received 9NC 1.5 mg/m² orally under fasting conditions daily for 5 days per week for 8 weeks. Results: Sixteen patients with median (range) age 62 (47–83) years, diagnoses of colorectal (six patients), lung (two patients), and other (eight patients) malignancies, received 83 [median (range) 4 (2–9)] weeks of therapy. Patients with toxicities greater than grade 2: were diarrhea (1), nausea (2), vomiting (2), fatigue (2), anemia (3), neutropenia (3), and febrile neutropenia (2). Three patients (lung, unknown primary, and colon) had stable disease for eight weeks. The mean±SD of 9NC AUC_food and 9NC AUC_fast (n=9) were 330±182 and 558±379 ng/ml·h, respectively (P<0.05). The mean±SD of 9AC AUC_food and 9AC AUC_fast (n=9) were 244±60 and 256±101 ng/ml·h, respectively (P>0.05). The mean ± SD ratio of 9NC AUC_food to AUC_fasting in individual patients (n=9) was 0.67±0.22. The mean ± SD ratio of 9AC AUC_food to AUC_fasting in individual patients (n=9) was 1.14±0.61. Conclusions: Co-administration of 9NC with food reduces the oral absorption of 9NC; however, there was no difference in the exposure of 9AC. The is high interpatient variability in the effect of food on the absorption of 9NC and the interpatient variability in the effect of food on the disposition of 9AC is even greater when compared to 9NC. Supported, in part, by grant NCI 2P30 CA47904, grant NIH / NCRR / GCRC /#5M01 RR00056, and a grant from Supergen Inc., Dublin, California     

Plasma and cerebrospinal fluid pharmacokinetics of ABT-888 after oral administration in non-human primates

Purpose

ABT-888 inhibits poly(ADP-ribose) polymerase (PARP) and may enhance the efficacy of chemotherapy and radiation in CNS tumors. We studied the plasma and cerebrospinal fluid (CSF) pharmacokinetics (PK) of ABT-888 in a non-human primate (NHP) model that is highly predictive of human CSF penetration.

Methods

ABT-888, 5 mg/kg, was administered orally to three NHPs. Serial blood and CSF samples were obtained. Plasma and CSF concentrations of ABT-888 were measured using LC/MS/MS, and the resulting concentration versus time data were evaluated using non-compartmental and compartmental PK methods.

Results

The CSF penetration of ABT-888 was 57 ± 7% (mean ± SD). The peak ABT-888 concentration in the plasma was 0.62 ± 0.18 μM. Plasma and CSF AUC_0–∞ were 3.7 ± 1.7 and 2.1 ± 0.8 μM h. PARP inhibition in peripheral blood mononuclear cells was evident 2 h after ABT-888 administration.

Conclusion

The CSF penetration of ABT-888 after oral administration was 57%. Plasma and CSF concentrations were in the range that has been shown to inhibit PARP activity in vivo in humans.     

A phase I, randomized, open-label study of the multiple-dose pharmacokinetics of vemurafenib in patients with BRAF V600E mutation-positive metastatic melanoma

Purpose

This study characterized the multiple-dose pharmacokinetics of vemurafenib 240–960 mg twice daily (bid) in BRAF ^V600E mutation-positive metastatic melanoma patients, using the commercial formulation (240-mg microprecipitated bulk powder film-coated tablets).

Methods

Melanoma patients (N = 52) were randomly allocated to four vemurafenib dose cohorts (240, 480, 720, or 960 mg bid for 14 days). After the day 15 morning dose, doses were interrupted until day 22, at which point patients were restarted on vemurafenib. Serial pharmacokinetic samples were collected after the morning dose on days 1, 9, and 15; trough pharmacokinetic samples were collected on day 2.

Results

Vemurafenib concentration increased with multiple doses to steady state at day 15; C _max, AUC_0–8h, and AUC_0–168h increased between 3.3- and 3.8-fold across the fourfold dose range tested. Statistical analysis indicated dose proportionality across the dose range of 240–960 mg bid. Day 15 mean accumulation ratios (ratio of AUC_0–8h on day 15/AUC_0–8h on day 1) ranged from ~19 to 25 across cohorts. At steady state, the peak-to-trough ratio for vemurafenib exhibited a relatively flat concentration–time profile throughout the bid dosing interval. During dose interruption (days 15–22), mean vemurafenib trough concentrations decreased to minimal levels; vemurafenib exhibited a mean terminal phase half-life of 31.5–38.4 h.

Conclusions

Vemurafenib plasma concentration accumulates with multiple bid doses of 240 mg. Vemurafenib exposure (AUC and C _max) is dose proportional over the 240- to 960-mg bid dose range and exhibits constant drug levels over the bid dosing interval.