Dosing in Heavy-weight/Obese Patients with the LMWH, Tinzaparin: A Pharmacodynamic Study

This pharmacodynamic study examined weight-based dosing of the low molecular weight heparin (LMWH), tinzaparin, in heavyweight/obese subjects. Single doses (175 and 75 IU/kg) were administered subcutaneously (SC) to 37 healthy heavy-weight subjects (101-165 kg; 26-61 kg/m2). AUA and Amax values of anti-Xa and anti-IIa activities were consistent over these body weight and body mass index (BMI) ranges, indicating that tinzaparin pharmacodynamics are not influenced by body weight or BMI. The range of AUA and Amax values in the study population overlapped that of historical control normal-weight subjects (<100 kg), indicating that weightadjusted tinzaparin dosing yields a predictable response regardless of body weight or BMI. Tinzaparin was well tolerated, although injection site bruising was commonly reported. SC tinzaparin dosing in heavy or obese patients is appropriate based on body weight alone; the dose need not be capped at a maximal absolute dose.

Effects of Fostamatinib on the Pharmacokinetics of the CYP2C8 Substrate Pioglitazone: Results From In Vitro and Phase 1 Clinical Studies

Fostamatinib is a prodrug that undergoes gastrointestinal tract dephosphorylation to form the active metabolite, R406. Here we report its cytochrome P450-inducing potential. In vitro, R406 3 and 10 μM induced CYP2C8 to levels representing 53% and 75%, respectively, of the level achieved by the positive control, rifampicin. Induction of other enzymes was minor. The effect of fostamatinib (100 mg twice daily) on the pharmacokinetics of a single oral 30-mg dose of the CYP2C8 substrate pioglitazone and its metabolite, hydroxy pioglitazone, was then investigated (open-label, nonrandomized, 2-period phase I study [n = 15]). Coadministration of fostamatinib and pioglitazone (vs pioglitazone alone) was associated with lower mean maximum plasma concentration values for pioglitazone (geometric least-squares mean ratio, 82.8; 90% confidence interval, 64.2-106.8) and hydroxy pioglitazone (90.9; 78.6-105.1), an increase in pioglitazone AUC (117.8; 108.4-128.0), a decrease in hydroxy pioglitazone AUC(0-t) (89.7; 78.9-101.9), and an increase in pioglitazone geometric mean t1/2λz (9.4-12.8 hours). No tolerability concerns were identified upon coadministration. These data suggest that although clinical significance has not been formally evaluated, fostamatinib is unlikely to have a clinically significant effect on the pharmacokinetics of pioglitazone (which may be extrapolated to other CYP2C8 substrates). However, vigilance is advised should these agents be prescribed together.

Osimertinib Western and Asian clinical pharmacokinetics in patients and healthy volunteers: implications for formulation, dose, and dosing frequency in pivotal clinical studies

PURPOSE

Osimertinib (AZD9291) 80 mg once daily is approved by the US FDA for the treatment of patients with metastatic EGFR T790M-positive NSCLC whose disease has previously progressed on EGFR-TKI therapy. Osimertinib PK was evaluated to define the dose and dosing interval, whether a fixed-dosing approach can be used globally, and the impact of formulation and food on exposure.

METHODS

AURA (NCT01802632): single- and multiple-dose PK of osimertinib (20-240 mg daily) was determined in patients with advanced NSCLC. Bioavailability study (NCT01951599): single-dose PK of osimertinib (20 mg) was determined in healthy volunteers with administration of capsule, solution, or tablet formulations fasted, and as a tablet in the fed and fasted state.

RESULTS

Osimertinib was slowly absorbed and displayed dose-proportional increases in exposure from 20 to 240 mg. Distribution was extensive and clearance low to moderate, resulting in a mean half-life of 48.3 h. Steady state was achieved by 15 days of dosing, consistent with single-dose PK, with a peak-to-trough ratio of 1.6. Two active metabolites circulated at ~10 % of osimertinib exposure. Ethnicity did not appear to affect exposure. Osimertinib PK profiles in healthy volunteers were similar to those in patients and were unaffected by formulation. Food caused a clinically insignificant increase in exposure.

CONCLUSIONS

Osimertinib PK supports once-daily dosing; the same dose for Asian and non-Asian populations; a fixed-dosing approach; a minimal effect of food on exposure; and a switch to tablet formulation without alteration to dose or schedule. Osimertinib plasma concentrations are sustained throughout the dosing period, which is considered optimal for efficacy.

Safety, Pharmacokinetics and Immune Effects in Normal Volunteers of CPG 10101 (ACTILON™), an Investigational Synthetic Toll-like Receptor 9 Agonist

CPG 10101 (ACTILON™) is a novel potent and selective unmethylated cytidine-phosphate-guanosine (CpG)-containing oligodeoxynucleotide agonist of Toll-like receptor 9 (TLR9) being developed for the treatment of chronic infections such as HCV.

Objectives and Methods

In this randomized, double-blind, placebo-controlled Phase I study in 48 normal volunteers, we investigated the safety, pharmacokinetic parameters and immune effects of subcutaneous administration of CPG 10101. Five sequential escalating doses from 0.25 to 20 mg were administered twice, 14 days apart. In addition, a 4 mg dose was administered twice weekly for four weeks.

Results

A maximum tolerated dose was not reached and the adverse event profile was consistent with the known immunostimulatory effects of TLR9 agonists, mostly consisting of injection site reactions or flu-like symptoms that were generally mild in intensity. CPG 10101 induced interferons, cytokines and chemokines in a pattern consistent with the biology of TLR9. The most sensitive marker was IP-10/CXCL10, whose induction was detected in some subjects even at the 0.25 mg dose. Some cytokines showed transient circulating levels, while the levels of others such as the antiviral cytokine 2’,5’-oligoadenylate synthetase were sustained for several days.

Conclusion

This study warrants further investigation of CPG 10101 for the treatment of chronic infections such as HCV.

Phase 1 study of two merozoite surface protein 1 (MSP1(42)) vaccines for Plasmodium falciparum malaria

Objectives:

To assess the safety and immunogenicity of two vaccines, MSP1₄₂-FVO/Alhydrogel and MSP1₄₂-3D7/Alhydrogel, targeting blood-stage Plasmodium falciparum parasites.

Design:

A Phase 1 open-label, dose-escalating study.

Setting:

Quintiles Phase 1 Services, Lenexa, Kansas between July 2004 and November 2005.

Participants:

Sixty healthy malaria-naïve volunteers 18–48 y of age.

Interventions:

The C-terminal 42-kDa region of merozoite surface protein 1 (MSP1₄₂) corresponding to the two allelic forms present in FVO and 3D7 P. falciparum lines were expressed in Escherichia coli, refolded, purified, and formulated on Alhydrogel (aluminum hydroxide). For each vaccine, volunteers in each of three dose cohorts (5, 20, and 80 μg) were vaccinated at 0, 28, and 180 d. Volunteers were followed for 1 y.

Outcome Measures:

The safety of MSP1₄₂-FVO/Alhydrogel and MSP1₄₂-3D7/Alhydrogel was assessed. The antibody response to each vaccine was measured by reactivity to homologous and heterologous MSP1₄₂, MSP1₁₉, and MSP1₃₃ recombinant proteins and recognition of FVO and 3D7 parasites.

Results:

Anti-MSP1₄₂ antibodies were detected by ELISA in 20/27 (74%) and 22/27 (81%) volunteers receiving three vaccinations of MSP1₄₂-FVO/Alhydrogel or MSP1₄₂-3D7/Alhydrogel, respectively. Regardless of the vaccine, the antibodies were cross-reactive to both MSP1₄₂-FVO and MSP1₄₂-3D7 proteins. The majority of the antibody response targeted the C-terminal 19-kDa domain of MSP1₄₂, although low-level antibodies to the N-terminal 33-kDa domain of MSP1₄₂ were also detected. Immunofluorescence microscopy of sera from the volunteers demonstrated reactivity with both FVO and 3D7 P. falciparum schizonts and free merozoites. Minimal in vitro growth inhibition of FVO or 3D7 parasites by purified IgG from the sera of the vaccinees was observed.

Conclusions:

The MSP1₄₂/Alhydrogel vaccines were safe and well tolerated but not sufficiently immunogenic to generate a biologic effect in vitro. Addition of immunostimulants to the Alhydrogel formulation to elicit higher vaccine-induced responses in humans may be required for an effective vaccine.

Background: Generally, adults living in parts of the world where malaria is common develop protective immunity against the parasite. This means they may get infected but not become ill as a result. However, there are individuals, such as pregnant women and children under the age of five, who are more likely to develop symptoms of malaria due to no (or reduced) natural immunity. A successful malaria vaccine would stimulate an individual's immune system to respond to the malaria parasite and prevent serious clinical disease. Many different groups are currently developing potential vaccines. Several candidates are based on a protein called MSP1 (merozoite surface protein 1) which is found on the surface of the blood-stage form of the malaria parasite. However, in nature parasites carry different versions of the MSP1 protein, and ideally a successful vaccine would bring about immune responses against these different versions. The researchers carrying out this trial wanted to compare the safety and immune responses against candidate vaccines representing two different MSP1 proteins, which covered many different parasite lines. As a phase 1 trial, the study was carried out in healthy adult volunteers. Sixty individuals were assigned to receive an injection of the vaccines, either containing a recombinant protein analogous to the FVO parasite line (termed MSP1₄₂-FVO) or the 3D7 parasite line (termed MSP1₄₂-3D7) at three different dose levels. The trial's primary objective was to assess safety, which was done by collecting data on any abnormal signs or symptoms up to 14 d after each of three vaccinations. These outcomes were graded and then defined as related to the vaccine or not. The researchers also looked at antibody levels in participants' blood against different variants of the MSP1 protein, as well as using in vitro tests to see whether antibodies from vaccinated individuals could prevent malaria parasites from growing in lab culture.

What the trial shows: The safety outcomes of the trial showed that the most common type of side effect experienced by the volunteers was pain at the injection site. The vast majority of such events were graded as mild, although there was one single case of a severe event (high levels of pain experienced by one volunteer at the injection site). There was no significant association between the chance of side effects and the vaccine dosage that an individual received. Following vaccination, antibody levels against the protein on which the vaccine was based were detected, although these levels dropped over time. The researchers did not see a strong association between the vaccine dosage that individuals received and the level of antibody response. However, the two vaccines when compared seemed to be equally good at raising an immune response and both caused antibodies to be raised corresponding to different variants of the MSP1 protein. However, the antibodies raised did not seem to be particularly effective at preventing malaria parasites from growing in lab culture.

Strengths and limitations: Strengths of this study include a comparison of three different dosage levels of the vaccines under study, as well as a comparison of two vaccines based on the same protein, representing different parasite lines. Limitations to the study include the small number of participants, which makes the trial underpowered to detect all but large differences in side effects between the groups being compared. A placebo arm was not included in the trial, so it is not possible to be sure that the numbers of side effects observed here can be attributed to the vaccines or not. Finally, the procedure for assigning individuals to the two different vaccines involved alternation, rather than true randomization, which could have minimized the risk of bias.

Contribution to the evidence: The trial reported here is an essential step in vaccine development. The results provide the first evidence relating to safety for these two vaccines, and do not raise any safety concerns at this stage. Although the vaccines raised an immune response, the antibodies raised did not seem to have much of an effect on malaria parasites in vitro. While these vaccines are safe, alternative MSP1 vaccine formulations anticipated to bring about a greater immune response will likely be studied before proceeding to field studies.

Safety, pharmacokinetics and immune effects in normal volunteers of CPG 10101 (ACTILON), an investigational synthetic toll-like receptor 9 agonist

CPG 10101 (ACTILON) is a novel potent and selective unmethylated cytidine-phosphate-guanosine (CpG)-containing oligodeoxynucleotide agonist of Toll-like receptor 9 (TLR9) being developed for the treatment of chronic infections such as HCV.

OBJECTIVES AND METHODS

In this randomized, double-blind, placebo-controlled Phase I study in 48 normal volunteers, we investigated the safety, pharmacokinetic parameters and immune effects of subcutaneous administration of CPG 10101. Five sequential escalating doses from 0.25 to 20 mg were administered twice, 14 days apart. In addition, a 4 mg dose was administered twice weekly for four weeks.

RESULTS

A maximum tolerated dose was not reached and the adverse event profile was consistent with the known immunostimulatory effects of TLR9 agonists, mostly consisting of injection site reactions or flu-like symptoms that were generally mild in intensity. CPG 10101 induced interferons, cytokines and chemokines in a pattern consistent with the biology of TLR9. The most sensitive marker was IP-10/CXCL10, whose induction was detected in some subjects even at the 0.25 mg dose. Some cytokines showed transient circulating levels, while the levels of others such as the antiviral cytokine 2',5'-oligoadenylate synthetase were sustained for several days.

CONCLUSION

This study warrants further investigation of CPG 10101 for the treatment of chronic infections such as HCV.

Pharmacokinetics, pharmacodynamics, and safety assessment of palifermin (rHuKGF) in healthy volunteers

BACKGROUND

Palifermin is a recombinant human keratinocyte growth factor approved to decrease the incidence and duration of severe oral mucositis in patients with hematologic malignancies who received myelotoxic therapy requiring hematopoietic stem cell support.

METHODS

This randomized, double-blind, placebo-controlled study investigated the pharmacokinetics, pharmacodynamics, and safety of palifermin in healthy volunteers after single, escalating doses (60 to 250 mug/kg). Pharmacodynamic measurements (Ki67 staining) assessing buccal mucosal epithelial proliferation were performed at baseline and at 48 or 72 hours after dosing.

RESULTS

Exposure to palifermin increased approximately dose proportionally, with a 3-fold increase observed for a 4-fold increase in dose. Palifermin concentrations decreased sharply during the first 0.5 to 1.5 hours after dosing, slightly increased or plateaued between 1.5 and 6 hours, and subsequently decreased. The overall mean systemic clearance and volume of distribution at steady state were 590 mL/h/kg and 2000 mL/kg, respectively. The mean half-life ranged from 4.5 to 6 hours across the dose levels. The mean and SD ratio of Ki67 staining at 48 hours after dosing to baseline was 1.19 (0.24) for placebo, 2.02 (0.60) for 60 mug/kg, 3.04 (1.13) for 120 mug/kg, and 4.66 (0.77) for 250 mug/kg-treated groups.

CONCLUSION

Palifermin exhibited linear pharmacokinetics and caused dose-dependent epithelial proliferation.

Effect of tolcapone on plasma levodopa concentrations after coadministration with levodopa/carbidopa to healthy volunteers

Tolcapone (Ro 40-7592) is a novel inhibitor of catechol-O-methyltransferase that is being developed for clinical use in the treatment of Parkinson's disease as add-on therapy to a combination of levodopa and a peripheral amino acid decarboxylase inhibitor (benserazide or carbidopa). The current single-blind, randomized study was designed to evaluate the effect of tolcapone compared with placebo on plasma levodopa concentrations in healthy volunteers concomitantly receiving 25 mg of carbidopa and 100 mg of levodopa (Sinemet 25-100) and to assess the tolerability and safety of this combination. Placebo or tolcapone at doses of 5, 10, 25, 50, 100, 200, 400, and 800 mg was coadministered orally with Sinemet 25-100. Each dose was tested in a crossover fashion in a new group of six participants who each received active drug on one occasion and placebo on the other. Tolcapone increased the area under the plasma concentration-time curve and half-life of levodopa approximately twofold, without appreciably increasing the peak concentration. The maximum effect on levodopa half-life was observed with the 200-mg dose. Adverse effects were minor at all doses.

The pharmacokinetic and pharmacodynamic interaction between zileuton and terfenadine

OBJECTIVES

The effects of zileuton on terfenadine pharmacokinetics, and the effects of terfenadine alone and the combination on the duration of the QTc interval and the morphology of the TU complex were examined.

METHODS

The study was double-blind, randomized, placebo-controlled, two period cross-over in 16 healthy volunteers. During each period, subjects received 60 mg of terfenadine every 12 h on days 1 to 7 and 600 mg of either zileuton or placebo for zileuton every 6 h on days 1 to 10. Blood samples were obtained on days 7 to 10 and serial ECGs were performed on days -1 and 7 in both periods.

RESULTS

The combination of zileuton and terfenadine was well tolerated. Coadministration of zileuton with terfenadine resulted in a significant increase in the mean AUC and Cmax of terfenadine by approximately 35% and the mean AUC and Cmax of carboxyterfenadine by approximately 15%. The maximum concentration of terfenadine observed in the study was 9.6 ng.ml-1. The addition of zileuton to terfenadine did not result in significant changes in the evaluated ECG-recordings (QTc interval and morphology of TU complex). The difference in means for both maximum and average QTc interval was very small (< or = 2.3 ms), and there were no clinically significant changes in individual values.

CONCLUSIONS

The relatively small pharmacokinetic effect of zileuton on terfenadine metabolism, with no change in the QTc interval, is unlikely to be of clinical significance. The interaction is minimal in comparison to the background variability of the population.

Preclinical and clinical studies on lymph node imaging using perflubron emulsion

A perflubron emulsion is being developed as a contrast agent to enhance lymph nodes on computed tomography (CT) images. The emulsion is administered by percutaneous injection into the drainage field of the lymph nodes to be imaged. A series of preclinical studies was conducted to investigate the efficacy of the perflubron emulsion for enhancement of lymph nodes on CT images. The effects of dose (0.10 to 0.50 mL), application of massage, and route of administration were investigated in healthy New Zealand white rabbits. Results of these studies demonstrated that doses as low as 0.15 mL were efficacious for consistent enhancement of axillary lymph nodes on CT images after subcutaneous injections in the forepaw. Application of massage to the injection site decreased the time for maximum nodal enhancement from approximately 7 days to 2 days postinjection. A pilot study conducted in 18 healthy, male volunteers indicated dose-related enhancement of axillary lymph nodes on CT images following subcutaneous injections of the emulsion in the hand. Other than mild, transient injection-site discomfort, no clinically significant side effects were observed. These data demonstrate that the perflubron emulsion is safe and can enhance axillary lymph nodes on CT images following injections in the hand.

Comparison of the effects of etodolac SR and naproxen on gastro-intestinal blood loss

A single-blind, open-label controlled study was carried out in 30 healthy male volunteers to compare gastro-intestinal blood loss before, during and after treatment with a new, sustained-release formulation of the non-steroidal anti-inflammatory agent etodolac (etodolac SR) or with naproxen. Subjects remained at the study centre for 21 days and received placebo twice daily from Days 1 to 7 after which they were assigned at random to receive etodolac SR either as a single 600 mg or 1200 mg daily dose or naproxen (500 mg twice daily) for 7 days and then placebo again until the end of the study. There were 10 subjects in each of the three treatment groups. Gastro-intestinal blood loss was measured by the 51Cr-tagged erythrocyte method and was averaged for Days 4 to 7 (pre-treatment baseline), Days 11 to 14 (treatment period), and Days 17 to 20 (post-treatment period). The mean daily gastro-intestinal blood loss during the treatment period was significantly greater for the naproxen-treated group (1.20 ml/day) than for the 600 mg etodolac SR group (0.38 ml/day) and the 1200 mg etodolac SR group (0.45 ml/day). These results show that etodolac SR in doses of 600 mg and 1200 mg/day causes significantly less gastro-intestinal blood loss than does naproxen 500 mg twice daily.

An evaluation of the biological response to Fraxiparine, (a low molecular weight heparin) in the healthy individual

The tolerance of a low molecular weight heparin (Fraxiparine, Choay, Paris, France) in normal individuals was determined using a two part investigation. Study 1 consisted of administering escalating doses of Fraxiparine in a single blinded, placebo controlled, rising dose tolerance evaluation. The daily doses tested were 3750 U AXA IC, 7500 U AXa IC, 11250 U AXa IC, 15000 U AXa IC, and 22500 U AXa IC Fraxiparine subcutaneously for 5 consecutive days. In study 2, we compared the tolerance of unfractionated heparin (UH) administered as 5000 IU every 8 hours, to that of 7500 U AXa IC/day or 15000 U AXa IC/day of Fraxiparine administered once daily. Our results indicated very good tolerance to this low molecular weight heparin (LMWH) at doses up to and including 22500 U AXa IC/day. We observed significantly elevated increases in transaminases following LMWH administration. In our second study we observed that the increase in serum transaminases seen after 15000 U AXa IC/day Fraxiparine was without significant difference from that observed following UH (5000 IU every 8 hours). AXa examination revealed an accumulation of AXa effect after 5 days of administration at doses greater than 15000 U AXa IC, and there was good correlation between AXa and APTT at Fraxiparine doses greater than 15000 U AXa IC/day. No thrombocytopenia was associated with Fraxiparine. We conclude that Fraxiparine is relatively well tolerated and shows accumulation after daily dosing with greater than 15000 U AXa IC.