Integrated preclinical and clinical development of S-trans, trans-Farnesylthiosalicylic Acid (FTS, Salirasib) in pancreatic cancer.

PURPOSE: S-trans,trans-Farnesylthiosalicylic Acid (FTS, salirasib) inhibits Ras-dependent cell growth by dislodging all isoforms of Ras, including mutant Ras, from the plasma membrane. This study evaluated the activity, safety, and toxicity of salirasib in preclinical models and patients with metastatic pancreatic adenocarcinoma (PDA). PATIENTS AND METHODS: In the preclinical study, salirasib was tested, alone and in combination with gemcitabine, in patient derived xenografts (PDX) of PDA. In the clinical study, treatment-naïve patients with advanced, metastatic PDA were treated with a standard dose schedule of gemcitabine and salirasib 200-800 mg orally (PO) twice daily (bid) for 21 days every 28 days. Tissue from preclinical models and patients' biopsies were collected pre-treatment and on Cycle (C) 1, Day (D) 9 to characterize the effect of gemcitabine and salirasib on activated Ras protein levels. Plasma samples for pharmacokinetics were collected for salirasib administered alone and in combination. RESULTS: Salirasib inhibited the growth of 2/14 PDX models of PDA and modulated Ras signaling in these tumors. Nineteen patients were enrolled. No DLTs occurred. Common adverse events included hematologic and gastrointestinal toxicities and fatigue. The median overall survival was 6.2 months and the 1 year survival 37 %. In 2 patients in whom paired tissue biopsies were available, Ras and KRas protein levels were decreased on C1D9. Salirasib exposure was not altered by gemcitabine and did not correlate with PD outcomes. CONCLUSION: The combination of gemcitabine and salirasib appears well-tolerated, with no alteration of salirasib exposure, and exerted clinical and PD activity in PDA.

Phase I Pharmacokinetic Study of Fixed-Dose Combinations of Ibuprofen and Acetaminophen in Healthy Adult and Adolescent Populations.

INTRODUCTION: A fixed-dose combination (FDC) of ibuprofen and acetaminophen has been developed that provides greater analgesic efficacy than either agent alone at the same doses without increasing the risk for adverse events. METHODS: We report three clinical phase I studies designed to assess the pharmacokinetics (PK) of the FDC of ibuprofen/acetaminophen 250/500 mg (administered as two tablets of ibuprofen 125 mg/acetaminophen 250 mg) in comparison with its individual components administered alone or together, and to determine the effect of food on the PK of the FDC. Two studies in healthy adults aged 18-55 years used a crossover design in which subjects received a single dose of each treatment with a 2-day washout period between each. In the third study, the bioavailability of ibuprofen and acetaminophen from a single oral dose of the FDC was assessed in healthy adolescents aged 12-17 years, inclusive. RESULTS: A total of 35 and 46 subjects were enrolled in the two adult studies, respectively, and 21 were enrolled in the adolescent study. Ibuprofen and acetaminophen in the FDC were bioequivalent to the monocomponents administered alone or together. With food, the maximum concentration (Cmax) for ibuprofen and acetaminophen from the FDC was reduced by 36% and 37%, respectively, and time to Cmax (i.e. tmax) was delayed. Overall drug exposure to ibuprofen or acetaminophen in the fed versus fasted states was similar. In adolescents, overall exposure to acetaminophen and ibuprofen was comparable with that in adults, with a slightly higher overall exposure to ibuprofen. Exposure to acetaminophen and ibuprofen in adolescents aged 12-14 years was slightly higher versus those aged 15-17 years. Adverse events were similar across all treatment groups. CONCLUSIONS: The FDC of ibuprofen/acetaminophen 250/500 mg has a PK profile similar to its monocomponent constituents when administered separately or coadministered, indicating no drug-drug interactions and no formulation effects. Similar to previous findings for the individual components, the rates of absorption of ibuprofen and acetaminophen from the FDC were slightly delayed in the presence of food. Overall, adolescents had similar exposures to acetaminophen and ibuprofen as adults, while younger adolescents had slightly greater exposure than older adolescents, probably due to their smaller body size. The FDC was generally well tolerated.

Antitumor activity and molecular effects of the novel heat shock protein 90 inhibitor, IPI-504, in pancreatic cancer.

Targeting Hsp90 is an attractive strategy for anticancer therapy because the diversity and relevance of biological processes are regulated by these proteins in most cancers. However, the role and mode of action of Hsp90 inhibitors in pancreatic cancer has not been studied. This study aimed to assess the antitumor activity of the Hsp90 inhibitor, IPI-504, in pancreatic cancer and to determine the biological effects of the agent. In vitro, we show that pharmacologic inhibition of Hsp90 by IPI-504 exerts antiproliferative effects in a panel of pancreatic cancer cells in a dose- and time-dependent manner. In pancreatic cancer xenografts obtained directly from patients with pancreas cancer, the agent resulted in a marked suppression of tumor growth. Although known Hsp90 client proteins were significantly modulated in IPI-504-treated cell line, no consistent alteration of these proteins was observed in vivo other than induction of Hsp70 expression in the treated xenografted tumors. Using a proteomic profiling analysis with isotope tags for relative and absolute quantitation labeling technique, we have identified 20 down-regulated proteins and 42 up-regulated proteins on IPI-504 treatment.tumor growth Identical changes were observed in the expression of the genes coding for these proteins in a subset of proteins including HSPA1B, LGALS3, CALM1, FAM84B, FDPS, GOLPH2, HBA1, HIST1H1C, HLA-B, and MARCKS. The majority of these proteins belong to the functional class of intracellular signal transduction, immune response, cell growth and maintenance, transport, and metabolism. In summary, we show that IPI-504 has potent antitumor activity in pancreatic cancer and identify potential pharmacologic targets using a proteomics and gene expression profiling.

Effects of meal type on the oral bioavailability of the ALK inhibitor ceritinib in healthy adult subjects.

Ceritinib is a potent inhibitor of anaplastic lymphoma kinase (ALK), which has shown acceptable safety and substantial antitumor activity in ALK-positive non-small cell lung cancer (NSCLC) patients. Two food-effect studies were conducted in healthy adults to investigate the influence of food on the oral bioavailability of ceritinib: a study with low- or high-fat meals at 500 mg and a study with a light snack at 750 mg. Compared with the fasted state, AUC0-∞ (90%CI) of ceritinib was increased by 58% (34%, 86%) after the intake of a low-fat meal, by 73% (46%, 105%) after the intake of a high-fat meal, and by 54% (19%, 99%) after the intake of a light snack. Safety assessments also suggested that food may improve gastrointestinal (GI) tolerability after a single ceritinib dose. Based on the pharmacokinetic results, it is essential to avoid any type of meal during dosing of ceritinib because the intake of food may increase the occurrence of exposure-dependent, non-GI toxicities at the labeled dose of 750 mg daily during fasting. A randomized trial is ongoing to determine an alternative way to give ceritinib (450 mg or 600 mg with food) that may enhance GI tolerability in ALK-positive NSCLC patients.

Effects of Subcutaneous Pasireotide on Cardiac Repolarization in Healthy Volunteers: a Single­Center, Phase I, Randomized, Four­Way Crossover Study.

The aim of this study was to evaluate the effects of subcutaneous pasireotide on cardiac repolarization in healthy volunteers. Healthy volunteers were randomized to one of four treatment sequences (n = 112) involving four successive treatments in different order: pasireotide 600 µg (therapeutic dose) or 1,950 µg (maximum tolerated dose) bid by subcutaneous injection (sc), placebo injection and oral moxifloxacin. Maximum ΔΔQTcI occurred 2 hours post-dose for both doses of pasireotide. Mean ΔΔQTcI was 13.2 milliseconds (90% CI: 11.4, 15.0) and 16.1 milliseconds (90% CI: 14.3, 17.9) for the 600 and 1,950 µg bid doses, respectively. Maximal placebo-subtracted change in QTcI from baseline for moxifloxacin was 11.1 (90% CI: 9.3, 12.9) milliseconds. Both pasireotide doses caused a reduction in heart rate: maximal heart rate change compared with placebo occurred at 1 hour for pasireotide 600 µg bid and at 0.5 hours for pasireotide 1,950 µg bid, with heart rate reductions of 10.4 and 14.9 bpm, respectively. At the therapeutic dose of 600 µg, pasireotide has a modest QT-prolonging effect. The relatively small increase of ∼3 milliseconds in ΔΔQTcI in the presence of a 3.25-fold increase in dose suggests a relatively flat dose­effect relationship of pasireotide on ΔΔQTcI in healthy volunteers. No safety concerns for pasireotide were identified during the study.

Safety, tolerability, and pharmacokinetics of a single dose of pasireotide long-acting release in healthy volunteers: a single-center Phase I study.

OBJECTIVE: This study was conducted to evaluate the safety, tolerability, and pharmacokinetics (PKs) of different doses of a long-acting release (LAR) formulation of pasireotide in healthy subjects. DESIGN: Single-center, open-label, randomized Phase I study. METHODS: Twelve healthy male subjects received a single s.c. dose of pasireotide 300 µg followed by a washout period of 7 days (or at least 5 days), before receiving an i.m. injection of pasireotide -LAR 40 mg (n=5) or 60 mg (n=7). Assessments included adverse events (AEs), PKs, and glucose, insulin, glucagon, and HbA1c levels. RESULTS: Pasireotide LAR showed an extended-release profile over 1 month with two concentration peaks observed 1 and around 20 days after injection. The area under curve exposure of pasireotide LAR was dose proportional when the dose levels were compared, and the bioavailability of the LAR relative to the s.c. formulation was complete. Administration of pasireotide LAR resulted in an increase in fasting and postprandial glucose levels; however, an attenuation of the hyperglycemic effect was observed after 15 days. The most frequently reported AEs were mild-to-moderate diarrhea, abdominal pain, and flatulence. Only gastrointestinal AEs and injection site reactions were suspected to be drug related. CONCLUSIONS: Pasireotide LAR was generally well tolerated with mostly mild AEs at doses up to 60 mg and showed a dose-proportional, extended-release profile in healthy subjects. Based on the favorable results of this study, further clinical development of pasireotide LAR is under way, which will give insight into the PKs, efficacy, and safety of pasireotide LAR in patient populations.

Effect of hepatic impairment on the pharmacokinetics of pasireotide (SOM230): results from a multicenter phase I study.

Pasireotide is a novel, multireceptor-targeted somatostatin analogue with high affinity for sst(1,2,3) and sst(5) under clinical evaluation in tumors of neuroendocrine origin, including Cushing's disease, acromegaly, and neuroendocrine tumors. In this phase I, open-label, multicenter study, the pharmacokinetics and safety of a single subcutaneous (SC) injection of pasireotide 600 µg were evaluated in adults with normal hepatic function (n = 15) and mild (n = 6), moderate (n = 7), or severe hepatic impairment (n = 6). Following a single dose of pasireotide SC 600 µg, there were no significant differences in the plasma exposure of pasireotide between participants with normal hepatic function or mild hepatic impairment. Subjects with moderate and severe hepatic impairment showed an increase in AUC(∞) by 56% and 42%, respectively; this increase was 60% and 79% respectively, after adjusting for differences in age, BMI, and baseline serum albumin level between treatment groups. The incidence and severity of adverse events were similar across cohorts, with no clinically relevant differences in type or frequency of adverse events between cohorts. In conclusion, a single dose of pasireotide SC 600 µg was well tolerated in subjects with hepatic impairment. Drug exposure in subjects with mild hepatic impairment was similar to that seen in healthy volunteers, whereas subjects with moderate and severe hepatic impairment experienced higher exposure to pasireotide. Adjustment of the pasireotide dose may be required for patients with moderate and severe hepatic impairment.

Stromal cell-derived factor 1α mediates resistance to mTOR-directed therapy in pancreatic cancer.

PURPOSE: The factors preventing the translation of preclinical findings supporting the clinical development mTOR-targeted therapy in pancreatic cancer therapy remain undetermined. Stromal cell.derived factor 1α (SDF-1α)-CXCR4 signaling was examined as a representative microenvironmental factor able to promote mTOR-targeted therapy resistance in pancreatic cancer. EXPERIMENTAL DESIGN: Primary pancreas explant xenografts and in vitro experiments were used to perform pharmacodynamic analyses of SDF-1α-CXCR4 regulation of the mTOR pathway. Combinatorial effects of CXCR4, EGFR, and mTOR pharmacologic inhibition were evaluated in temsirolimus-resistant and -sensitive xenografts. Intratumoral gene and protein expressions of mTOR pathway effectors cyclin D1, c-Myc, and VEGF were evaluated. RESULTS: Baseline intratumoral SDF-1α gene expression correlated with temsirolimus resistance in explant models. SDF-1α stimulation of pancreatic cells resulted in CXCR4-mediated PI3-kinase-dependent S6-RP phosphorylation (pS6-RP) on exposure to temsirolimus. Combinatorial therapy with AMD3465 (CXCR4 small-molecule inhibitor) and temsirolimus resulted in effective tumor growth inhibition to overcome temsirolimus resistance. In contrast, SDF-1α exposure induced a temsirolimus-resistant phenotype in temsirolimus-sensitive explants. AMD3465 inhibited CXCR4-mediated intratumoral S6-RP phosphorylation and cyclin D and c-myc gene expression. Next, CXCR4 promoted intratumoral EGFR expression in association with temsirolimus resistance. Treatment with AMD3465, temsirolimus- and erlotinib-mediated tumor growth inhibition to overcome temsirolimus resistance in the explant model. Lastly, SDF-1α-CXCR4 signaling increased intratumoral VEGF gene and protein expression. CONCLUSIONS: SDF-1α-CXCR4 signaling represents a microenvironmental factor that can maintain mTOR pathway fidelity to promote resistance to mTOR-targeted therapy in pancreatic cancer by a variety of mechanisms such as recruitment of EGFR signaling and angiogenesis.

[18F]fluorodeoxyglucose positron emission tomography correlates with Akt pathway activity but is not predictive of clinical outcome during mTOR inhibitor therapy.

PURPOSE: Positron emission tomography (PET) with [(18)F]fluorodeoxyglucose (FDG-PET) has increasingly been used to evaluate the efficacy of anticancer agents. We investigated the role of FDG-PET as a predictive marker for response to mammalian target of rapamycin (mTOR) inhibition in advanced solid tumor patients and in murine xenograft models. PATIENTS AND METHODS: Thirty-four rapamycin-treated patients with assessable baseline and treatment FDG-PET and computed tomography scans were analyzed from two clinical trials. Clinical response was evaluated according to Response Evaluation Criteria in Solid Tumors, and FDG-PET response was evaluated by quantitative changes and European Organisation for Research and Treatment of Cancer (EORTC) criteria. Six murine xenograft tumor models were treated with temsirolimus. Small animal FDG-PET scans were performed at baseline and during treatment. The tumors were analyzed for the expression of pAkt and GLUT1. RESULTS: Fifty percent of patients with increased FDG-PET uptake and 46% with decreased uptake had progressive disease (PD). No objective response was observed. By EORTC criteria, the sensitivity of progressive metabolic disease on FDG-PET in predicting PD was 19%. Preclinical studies demonstrated similar findings, and FDG-PET response correlated with pAkt activation and plasma membrane GLUT1 expression. CONCLUSION: FDG-PET is not predictive of proliferative response to mTOR inhibitor therapy in both clinical and preclinical studies. Our findings suggest that mTOR inhibitors suppress the formation of mTORC2 complex, resulting in the inhibition of Akt and glycolysis independent of proliferation in a subset of tumors. Changes in FDG-PET may be a pharmacodynamic marker for Akt activation during mTOR inhibitor therapy. FDG-PET may be used to identify patients with persistent Akt activation following mTOR inhibitor therapy.