A randomized, double-blind, multicenter, phase 2b study to evaluate the safety and efficacy of a combination of tropifexor and cenicriviroc in patients with nonalcoholic steatohepatitis and liver fibrosis: Study design of the TANDEM trial.

BACKGROUND: Nonalcoholic steatohepatitis (NASH) is a multifactorial disease involving different contributing mechanisms, with no approved therapies so far. Tropifexor (TXR), a farnesoid X receptor agonist, and cenicriviroc (CVC), a chemokine receptor types 2/5 antagonist, target the steatotic, inflammatory, and/or fibrotic pathways involved in NASH. DESIGN: TANDEM (CLJC242A2201J; NCT03517540) is a 48-week, phase 2b, randomized, double-blind, multicenter study in 200 adult patients with biopsy-proven NASH and liver fibrosis. Patients will be randomized in a 1:1:1:1 ratio to receive either TXR 140 µg once daily (qd), CVC 150 mg qd, TXR 140 µg + CVC 150 mg qd, or TXR 90 µg + CVC 150 mg qd. The study comprises a 48-week treatment period and 4 weeks of follow-up. The key inclusion criterion is presence of NASH with fibrosis stage F2/F3 as seen on screening liver biopsy or on historical liver biopsy performed within 6 months prior to screening. OBJECTIVES: The primary objective is evaluation of the safety and tolerability of combination therapy compared with the monotherapies over 48 weeks. The secondary objective is to evaluate efficacy as assessed by ≥1-point improvement in liver fibrosis versus baseline or resolution of steatohepatitis after 48 weeks. SUMMARY: TANDEM will evaluate the combination of TXR and CVC with respect to safety and efficacy outcomes related to improvement in fibrosis or resolution of steatohepatitis. Given the effects of TXR and CVC in multiple pathophysiological pathways associated with NASH, combination therapy is likely to show additional benefits compared with monotherapy.

Pharmacokinetic interaction of the direct renin inhibitor aliskiren with furosemide and extended-release isosorbide-5-mononitrate in healthy subjects.

This study investigated the pharmacokinetics, safety, and tolerability of aliskiren administered alone or in combination with either the loop diuretic furosemide or an oral extended-release formulation of isosorbide-5-mononitrate (ISMN). In separate studies, 22 healthy subjects (ages 18-45 years) received either ISMN 40 mg or furosemide 20 mg once-daily for 3 days followed by a 3-day washout. Subjects then received aliskiren 300 mg once-daily for 7 days followed by combination therapy for 3 days. Pharmacokinetic assessments were taken at regular intervals over 24 h after dosing on the last day of each treatment period. At steady state, aliskiren AUC(tau) was decreased by 7% (geometric mean ratio [90% CI], 0.93 [0.84, 1.04]), and C(max) by 20% (0.80 [0.65, 0.97]) with furosemide coadministration compared with aliskiren administration alone. Aliskiren coadministration reduced furosemide AUC(tau) by 28% (0.72 [0.64, 0.81]) and C(max) by 49% (0.51 [0.39, 0.66]) compared with furosemide alone. Coadministration of aliskiren and ISMN was associated with only minor changes in the pharmacokinetic parameters of aliskiren (AUC(tau) 1.03 [0.90, 1.18]; C(max) 0.94 [0.69, 1.29]) and ISMN (AUC(tau) 0.88 [0.71, 1.10]; C(max) 0.94 [0.79, 1.13]). Headache and dizziness were the most common adverse events in both studies; dizziness and BP values below normal (SBP < 90 and/or DBP < 50 mmHg) were more frequent with aliskiren and ISMN coadministration than with either agent alone. Coadministration of aliskiren and ISMN had no clinically relevant effect on either aliskiren or ISMN pharmacokinetics. In conclusion, coadministration of aliskiren and furosemide reduced furosemide exposure and had a minor effect on aliskiren pharmacokinetics. The clinical significance of reduced systemic exposure to furosemide during coadministration of aliskiren is uncertain.

A study of the pharmacokinetic interactions of the direct renin inhibitor aliskiren with metformin, pioglitazone and fenofibrate in healthy subjects.

OBJECTIVE: Hypertension and type 2 diabetes are common comorbidities, thus many patients receiving antihypertensive medication require concomitant therapy with hypoglycemic or lipid-lowering drugs. The aim of these three studies was to investigate the pharmacokinetics, safety and tolerability of aliskiren, a direct renin inhibitor for the treatment of hypertension, co-administered with the glucose-lowering agents metformin or pioglitazone or the lipid-lowering agent fenofibrate in healthy volunteers. METHODS: In three open-label, multiple-dose studies, healthy volunteers (ages 18 to 45 years) received once-daily treatment with either metformin 1000 mg (n = 22), pioglitazone 45 mg (n = 30) or fenofibrate 200 mg (n = 21) and aliskiren 300 mg, administered alone or co-administered in a two-period study design. Blood samples were taken frequently on the last day of each treatment period to determine plasma drug concentrations. RESULTS: Co-administration of aliskiren with metformin decreased aliskiren area under the plasma concentration- time curve during the dose interval (AUC(tau)) by 27% (geometric mean ratio [GMR] 0.73; 90% confidence interval [CI] 0.64, 0.84) and maximum observed plasma concentration (C(max)) by 29% (GMR 0.71; 90% CI 0.56, 0.89) but these changes were not considered clinically relevant. Co-administration of aliskiren with fenofibrate had no effect on aliskiren AUC (GMR 1.05; 90% CI 0.96, 1.16) or C(max) (GMR 1.05; 90% CI 0.80, 1.38); similarly, co-administration of aliskiren with pioglitazone had no effect on aliskiren AUC(tau) (GMR 1.05; 90% CI 0.98, 1.13) or C(max) (GMR 1.01; 90% CI 0.84, 1.20). All other AUC and C(max) GMRs for aliskiren, metformin, pioglitazone, ketopioglitazone, hydroxypioglita-zone and fenofibrate were close to unity and the 90% CI were contained within the bioequivalence range of 0.80 to 1.25. CONCLUSION: Co-administration of aliskiren with metformin, pioglitazone or fenofibrate had no significant effect on the pharmacokinetics of these drugs in healthy volunteers. These findings indicate that aliskiren can be co-administered with metformin, pioglitazone or fenofibrate without the need for dose adjustment.

Pharmacokinetics of the oral direct renin inhibitor aliskiren in combination with digoxin, atorvastatin, and ketoconazole in healthy subjects: the role of P-glycoprotein in the disposition of aliskiren.

This study investigated the potential pharmacokinetic interaction between the direct renin inhibitor aliskiren and modulators of P-glycoprotein and cytochrome P450 3A4 (CYP3A4). Aliskiren stimulated in vitro P-glycoprotein ATPase activity in recombinant baculovirus-infected Sf9 cells with high affinity (K(m) 2.1 micromol/L) and was transported by organic anion-transporting peptide OATP2B1-expressing HEK293 cells with moderate affinity (K(m) 72 micromol/L). Three open-label, multiple-dose studies in healthy subjects investigated the pharmacokinetic interactions between aliskiren 300 mg and digoxin 0.25 mg (n = 22), atorvastatin 80 mg (n = 21), or ketoconazole 200 mg bid (n = 21). Coadministration with aliskiren resulted in changes of <30% in AUC(tau) and C(max,ss) of digoxin, atorvastatin, o-hydroxy-atorvastatin, and rho-hydroxy-atorvastatin, indicating no clinically significant interaction with P-glycoprotein or CYP3A4 substrates. Aliskiren AUC(tau) was significantly increased by coadministration with atorvastatin (by 47%, P < .001) or ketoconazole (by 76%, P < .001) through mechanisms most likely involving transporters such as P-glycoprotein and organic anion-transporting peptide and possibly through metabolic pathways such as CYP3A4 in the gut wall. These results indicate that aliskiren is a substrate for but not an inhibitor of P-glycoprotein. On the basis of the small changes in exposure to digoxin and atorvastatin and the <2-fold increase in exposure to aliskiren during coadministration with atorvastatin and ketoconazole, the authors conclude that the potential for clinically relevant drug interactions between aliskiren and these substrates and/or inhibitors of P-glycoprotein/CPY3A4/OATP is low.

Clinical pharmacokinetics and pharmacodynamics of aliskiren.

Aliskiren is the first orally bioavailable direct renin inhibitor approved for the treatment of hypertension. It acts at the point of activation of the renin-angiotensin-aldosterone system, or renin system, inhibiting the conversion of angiotensinogen to angiotensin I by renin and thereby reducing the formation of angiotensin II by angiotensin-converting enzyme (ACE) and ACE-independent pathways. Aliskiren is a highly potent inhibitor of human renin in vitro (concentration of aliskiren that produces 50% inhibition of renin 0.6 nmol/L). Aliskiren is rapidly absorbed following oral administration, with maximum plasma concentrations reached within 1-3 hours. The absolute bioavailability of aliskiren is 2.6%. The binding of aliskiren to plasma proteins is moderate (47-51%) and is independent of the concentration. Once absorbed, aliskiren is eliminated through the hepatobiliary route as unchanged drug and, to a lesser extent, through oxidative metabolism by cytochrome P450 (CYP) 3A4. Unchanged aliskiren accounts for approximately 80% of the drug in the plasma following oral administration, indicating low exposure to metabolites. The two major oxidized metabolites of aliskiren account for less than 5% of the drug in the plasma at the time of the maximum concentration. Aliskiren excretion is almost completely via the biliary/faecal route; 0.6% of the dose is recovered in the urine. Steady-state plasma concentrations of aliskiren are reached after 7-8 days of once-daily dosing, and the accumulation factor for aliskiren is approximately 2. After reaching the peak, the aliskiren plasma concentration declines in a multiphasic fashion. No clinically relevant effects of gender or race on the pharmacokinetics of aliskiren are observed, and no adjustment of the initial aliskiren dose is required for elderly patients or for patients with renal or hepatic impairment. Aliskiren showed no clinically significant increases in exposure during coadministration with a wide range of potential concomitant medications, although increases in exposure were observed with P-glycoprotein inhibitors. Aliskiren does not inhibit or induce CYP isoenzyme or P-glycoprotein activity, although aliskiren is a substrate for P-glycoprotein, which contributes to its relatively low bioavailability. Aliskiren is approved for the treatment of hypertension at once-daily doses of 150 mg and 300 mg. Phase II and III clinical studies involving over 12,000 patients with hypertension have demonstrated that aliskiren provides effective long-term blood pressure (BP) lowering with a good safety and tolerability profile at these doses. Aliskiren inhibits plasma renin activity (PRA) by up to 80% following both single and multiple oral-dose administration. Similar reductions in PRA are observed when aliskiren is administered in combination with agents that alone increase PRA, including diuretics (hydrochlorothiazide, furosemide [frusemide]), ACE inhibitors (ramipril) and angiotensin receptor blockers (valsartan), despite greater increases in the plasma renin concentration. Moreover, PRA inhibition and BP reductions persist for 2-4 weeks after stopping treatment, which is likely to be of benefit in patients with hypertension who occasionally miss a dose of medication. Preliminary data on the antiproteinuric effects of aliskiren in type 2 diabetes mellitus suggest that renoprotective effects beyond BP lowering may be possible. Further studies to evaluate the effects of aliskiren on cardiovascular outcomes and target organ protection are ongoing and will provide important new data on the role of direct renin inhibition in the management of hypertension and other cardiovascular disease.

Effects of aliskiren, a direct Renin inhibitor, on cardiac repolarization and conduction in healthy subjects.

This multicenter, double-blind study evaluated the effects of aliskiren, a direct renin inhibitor approved for hypertension, on cardiac repolarization and conduction. Healthy volunteers (n = 298) were randomized to aliskiren 300 mg, aliskiren 1200 mg, moxifloxacin 400 mg (positive control), or placebo once daily for 7 days. Digitized electrocardiograms were obtained at baseline and day 7 of treatment over 23 hours postdose. Placebo-adjusted mean changes from baseline in QTcF (Fridericia corrected), QTcI (individualized correction), PR, and QRS intervals were compared at each time point (time-matched analysis) and for values averaged across the dosing period (baseline-averaged analysis). In time-matched analysis, mean changes in QTcF with aliskiren were below predefined limits for QTc prolongation (mean increase <5 milliseconds; upper 90% confidence interval [CI] <10 milliseconds) except aliskiren 1200 mg at 23 hours (5.2 milliseconds; 90% CI 2.2, 8.1). With moxifloxacin, significant QTcF prolongation occurred at most time points, confirming the sensitivity of the assay. Baseline-averaged analysis was consistent with time-matched analysis. Instances of QTcF interval >450 milliseconds or a >30-millisecond increase from baseline with aliskiren (< or = 1%) were similar or lower than placebo (< or = 4%). Results were similar for QTcI. Aliskiren had no effect on PR or QRS duration. In conclusion, aliskiren at the highest approved dose (300 mg) and a 4-fold higher dose had no effect on cardiac repolarization or conduction in healthy volunteers.

Pharmacokinetics of the oral direct renin inhibitor aliskiren alone and in combination with irbesartan in renal impairment.

BACKGROUND: Aliskiren is an orally active direct renin inhibitor approved for the treatment of hypertension. This study assessed the effects of renal impairment on the pharmacokinetics and safety of aliskiren alone and in combination with the angiotensin receptor antagonist irbesartan. METHODS: This open-label study enrolled 17 males with mild, moderate or severe renal impairment (creatinine clearance [CL(CR)] 50-80, 30-49 and <30 mL/minute, respectively) and 17 healthy males matched for age and bodyweight. Subjects received oral aliskiren 300 mg once daily on days 1-7 and aliskiren coadministered with irbesartan 300 mg on days 8-14. Plasma aliskiren concentrations were determined by high-performance liquid chromatography/tandem mass spectrometry at frequent intervals up to 24 hours after dosing on days 1, 7 and 14. RESULTS: Renal clearance of aliskiren averaged 1280 +/- 500 mL/hour (mean +/- SD) in healthy subjects and 559 +/- 220, 312 +/- 75 and 243 +/- 186 mL/hour in patients with mild, moderate and severe renal impairment, respectively. At steady state (day 7), the geometric mean ratios (renal impairment : matched healthy volunteers) ranged from 1.21 to 2.05 for the area under the plasma concentration-time curve (AUC) over the dosage interval tau (24h) [AUC(tau)]) and from 0.83 to 2.25 for the maximum observed plasma concentration of aliskiren at steady state. Changes in exposure did not correlate with CL(CR), consistent with an effect of renal impairment on non-renal drug disposition. The observed large intersubject variability in aliskiren pharmacokinetic parameters was unrelated to the degree of renal impairment. Accumulation of aliskiren at steady state (indicated by the AUC from 0 and 24 hours [AUC(24)] on day 7 vs day 1) was similar in healthy subjects (1.79 [95% CI 1.24, 2.60]) and those with renal impairment (range 1.39-1.99). Coadministration with irbesartan did not alter the pharmacokinetics of aliskiren. Aliskiren was well tolerated when administered alone or with irbesartan. CONCLUSIONS: Exposure to aliskiren is increased by renal impairment but does not correlate with the severity of renal impairment (CL(CR)). This is consistent with previous data indicating that renal clearance of aliskiren represents only a small fraction of total clearance. Initial dose adjustment of aliskiren is unlikely to be required in patients with renal impairment.

Absorption, distribution, metabolism, and elimination of the direct renin inhibitor aliskiren in healthy volunteers.

Aliskiren (2(S),4(S),5(S),7(S)-N-(2-carbamoyl-2-methylpropyl)-5-amino-4-hydroxy-2,7-diisopropyl-8-[4-methoxy-3-(3-methoxypropoxy)phenyl]-octanamid hemifumarate) is the first in a new class of orally active, nonpeptide direct renin inhibitors developed for the treatment of hypertension. The absorption, distribution, metabolism, and excretion of [(14)C]aliskiren were investigated in four healthy male subjects after administration of a single 300-mg oral dose in an aqueous solution. Plasma radioactivity and aliskiren concentration measurements and complete urine and feces collections were made for 168 h postdose. Peak plasma levels of aliskiren (C(max)) were achieved between 2 and 5 h postdose. Unchanged aliskiren represented the principal circulating species in plasma, accounting for 81% of total plasma radioactivity (AUC(0-infinity)), and indicating very low exposure to metabolites. Terminal half-lives for radioactivity and aliskiren in plasma were 49 h and 44 h, respectively. Dose recovery over 168 h was nearly complete (91.5% of dose); excretion occurred almost completely via the fecal route (90.9%), with only 0.6% recovered in the urine. Unabsorbed drug accounted for a large dose proportion recovered in feces in unchanged form. Based on results from this and from previous studies, the absorbed fraction of aliskiren can be estimated to approximately 5% of dose. The absorbed dose was partly eliminated unchanged via the hepatobiliary route. Oxidized metabolites in excreta accounted for at least 1.3% of the radioactive dose. The major metabolic pathways for aliskiren were O-demethylation at the phenyl-propoxy side chain or 3-methoxy-propoxy group, with further oxidation to the carboxylic acid derivative.

Effect of clopidogrel on the steady-state pharmacokinetics of fluvastatin.

This study assessed the effects of clopidogrel, a CYP 2C9 inhibitor, on fluvastatin pharmacokinetics in healthy volunteers. The effects of combined clopidogrel-fluvastatin treatment on platelet function were also determined. Subjects received 80 mg fluvastatin (extended-release formulation) alone on days 1 through 9, 80 mg fluvastatin and 300 mg clopidogrel (loading dose) on day 10, and 80 mg fluvastatin and 75 mg clopidogrel (maintenance dose) on days 11 through 19. Compared to treatment with fluvastatin alone, fluvastatin AUC was similar and C(max) increased marginally (15.7%) with concomitant treatment with clopidogrel. Platelet aggregation was inhibited by clopidogrel by 33% two hours after the loading dose and by 47% at steady state, similar to that reported for clopidogrel alone treatment. The authors conclude that coadministration of fluvastatin and clopidogrel has no clinically relevant effect on fluvastatin pharmacokinetics or on platelet inhibition by clopidogrel.

Pharmacokinetics, safety, and tolerability of the novel oral direct renin inhibitor aliskiren in elderly healthy subjects.

This open-label, multicenter study compared the pharmacokinetics and safety of the oral direct renin inhibitor aliskiren in 29 elderly (>or=65 years) and 28 young (18-45 years) healthy subjects. Plasma drug concentrations were determined for up to 168 hours following a single 300-mg oral dose of aliskiren. In elderly compared with young subjects, AUC(0-infinity) was 57% higher (ratio of geometric means 1.57, 90% confidence interval: 1.19, 2.06; P = .008) and C(max) was 28% higher (1.28, 90% confidence interval: 0.91, 1.79; P=.233). Other parameters, including t(max) and Vd/F, were similar between age groups. No differences in aliskiren exposure were observed between subjects ages 65 to 74 years (n=16) and >or=75 years (n=13). Aliskiren was well tolerated by all age groups, including the very elderly. In conclusion, aliskiren exposure is modestly increased in elderly subjects. Based on its wide therapeutic index and shallow dose response for blood pressure lowering, no initial dose adjustment should be needed for elderly patients.

Pharmacokinetics, safety, and tolerability of the oral Renin inhibitor aliskiren in patients with hepatic impairment.

Aliskiren is the first in a new class of orally active, direct renin inhibitors for the treatment of hypertension. This open-label, nonrandomized, single-center, parallel-group study compared the pharmacokinetics and safety of a single 300-mg oral dose of aliskiren in patients with mild, moderate, or severe hepatic impairment to that in healthy subjects. When pooled across subgroups, there were no significant differences between patients with hepatic impairment and healthy subjects in aliskiren AUC(0-infinity) (ratio of geometric means, 1.12; 90% confidence interval, 0.85, 1.48) or Cmax (mean ratio, 1.19; 90% confidence interval, 0.84, 1.68), and there was no correlation between severity of hepatic impairment and either AUC(0-infinity) or Cmax. Aliskiren was well tolerated by healthy subjects and patients with hepatic impairment. In conclusion, hepatic impairment has no significant effect on the pharmacokinetics of aliskiren following single-dose administration, and dosage adjustment is unlikely to be needed in patients with liver disease.

Aliskiren, a novel orally effective renin inhibitor, exhibits similar pharmacokinetics and pharmacodynamics in Japanese and Caucasian subjects.

AIMS: Aliskiren is the first in a new class of orally effective renin inhibitors for the treatment of hypertension. This study compared the pharmacokinetic and pharmacodynamic properties of aliskiren in Japanese and Caucasian subjects. METHODS: In this open-label, single-centre, parallel-group, single- and multiple-dose study, 19 Japanese and 19 Caucasian healthy young male subjects received a single 300-mg oral dose of aliskiren on day 1 and then aliskiren 300 mg once daily on days 4-10. Blood samples were collected for the measurement of plasma aliskiren concentration, plasma renin concentration (PRC) and plasma renin activity (PRA). RESULTS: Pharmacokinetic parameters were comparable in Japanese and Caucasian subjects following administration of a single dose of aliskiren {ratio of geometric means: C(max) 1.12 [90% confidence interval (CI) 0.88, 1.43]; AUC(0-72 h) 1.19 [90% CI 1.02, 1.39]} and at steady state [mean ratio: C(max) 1.30 (90% CI 1.00, 1.70); AUC(0-tau) 1.16 (90% CI 0.95, 1.41)]. There was no notable difference in the plasma half-life of aliskiren between Japanese and Caucasian groups (29.7 +/- 10.2 h and 32.0 +/- 6.6 h, respectively). At steady state, peak PRC level and AUC for the concentration-time plot were not significantly different between Japanese and Caucasian subjects (P = 0.64 and P = 0.80, respectively). A single oral dose of aliskiren significantly reduced PRA to a similar extent in Japanese and Caucasian subjects (by 87.5% and 85.7%, respectively, compared with baseline; P < 0.01). Aliskiren was well tolerated by both ethnic groups. CONCLUSIONS: The oral renin inhibitor aliskiren demonstrated similar pharmacokinetic and pharmacodynamic properties in Japanese and Caucasian subjects.

Aliskiren exhibits similar pharmacokinetics in healthy volunteers and patients with type 2 diabetes mellitus.

BACKGROUND: The renin system is an attractive target for antihypertensive therapy in patients with diabetes mellitus. However, diabetes is associated with changes in gastrointestinal, renal and hepatic function that may affect the absorption and disposition of oral drugs. This study compared the pharmacokinetics and pharmacodynamics of the orally active direct renin inhibitor, aliskiren, in healthy volunteers and patients with type 2 diabetes. METHODS: This was an open-label study conducted in 30 patients with type 2 diabetes and 30 healthy volunteers matched for age, bodyweight and race. Following a 10-hour fast, all participants received a single oral dose of aliskiren 300mg. Blood samples were taken at frequent intervals for 96 hours post-dose for determination of plasma concentrations of aliskiren (using a high-performance liquid chromatography-tandem mass spectroscopy method). Plasma renin activity (PRA) and renin concentration (RC) were also measured for 24 hours after dosing. RESULTS: Aliskiren exhibited similar pharmacokinetics in patients with type 2 diabetes and healthy volunteers. Exposure to aliskiren was slightly higher in patients with type 2 diabetes compared with healthy volunteers (mean area under the plasma concentration-time curve from 0 to 24 hours 1859 vs 1642 ng . h/mL; maximum observed plasma drug concentration 394 vs 348 ng/mL), while apparent clearance corrected for bioavailability was slightly lower (205 vs 234 L/h) and elimination half-life slightly longer (44 vs 39.9 hours), but there were no statistically significant differences for any pharmacokinetic parameters. There was no significant correlation between glycaemic control (% glycosylated haemoglobin) and any of the measured pharmacokinetic parameters in patients with type 2 diabetes. Aliskiren caused sustained suppression of PRA for at least 24 hours after dosing despite increasing RC; there were no major differences in the pharmacodynamic effects of aliskiren between patients with type 2 diabetes and healthy volunteers. Aliskiren was well tolerated in both patient groups, with no clinically significant changes in laboratory values and a low risk of adverse events. CONCLUSION: Aliskiren showed a similar pharmacokinetic profile in healthy volunteers and patients with type 2 diabetes, and administration of a single oral 300 mg dose of aliskiren was well tolerated by both patients and healthy volunteers. The pharmacodynamic effects of aliskiren were also similar in healthy volunteers and diabetic patients, with sustained inhibition of renin system activity observed for at least 24 hours after dosing.

Phase I and pharmacologic study of PKI166, an epidermal growth factor receptor tyrosine kinase inhibitor, in patients with advanced solid malignancies.

PURPOSE: This phase I study was conducted to assess the tolerability, pharmacokinetics, and antitumor activity of the oral, selective epidermal growth factor receptor tyrosine kinase inhibitor PKI166 in patients with advanced solid malignancies. EXPERIMENTAL DESIGN: PKI166 was first given once daily continuously and in the second part of the study once daily for 2 weeks every 4 weeks to establish the maximum tolerated dose (MTD). Ten additional patients were studied at MTD to acquire additional safety information and characterize the effect of food intake on PKI166 pharmacokinetics. Pharmacokinetics of PKI166 were characterized after single and multiple doses at all dose levels. RESULTS: Fifty-four patients received a total of one hundred sixteen 28-day cycles of PKI166. Dose-limiting transaminase elevations were observed in two of seven and two of eight patients using 50 and 100 mg PKI166 continuously. In the second part with PKI166 once daily for 2 weeks every 4 weeks, MTD was set at 750 mg. Dose-limiting toxicity consisted of diarrhea, skin rash, and transaminase elevations. Pharmacokinetic analysis revealed fast absorption, a linear dose-response relationship without drug accumulation after multiple doses. At MTD, no significant influence of food intake on PKI166 pharmacokinetics was observed. Stable disease for more than two cycles was observed in 11 patients. CONCLUSIONS: PKI166 given once daily for 2 weeks every 4 weeks is well tolerated with linear pharmacokinetics, compatible with once daily dosing, and without significant effect of food intake on absorption. The recommended dose for further studies is 750 mg once daily for 2 weeks every 4 weeks.

Pharmacologic demonstration of the synergistic effects of a combination of the renin inhibitor aliskiren and the AT1 receptor antagonist valsartan on the angiotensin II-renin feedback interruption.

Interrupting the renin-angiotensin system (RAS) with a usual daily dose of a single-site RAS inhibitor does not achieve complete and long-lasting pharmacologic blockade. Hormonal and BP effects were compared for 48 h after administration of single oral doses of 300 mg (high dose) of the renin inhibitor aliskiren (A300) and 160 mg (standard antihypertensive dose) of the AT1 receptor antagonist valsartan (V160) and their combination each at half dose (A150+V80) in 12 mildly sodium-depleted normotensive individuals. In this double-blind, placebo-controlled, randomized, four-period crossover study, A300 decreased plasma renin activity and angiotensin I and II levels for 48 h, stimulated immunoreactive active renin release more strongly than V160, and decreased urinary aldosterone excretion for a longer duration than V160. In contrast to V160, the A150+V80 combination did not increase plasma angiotensins. The renin and aldosterone effects of the A150+V80 combination were similar to those of A300 and greater than those of V160. When plasma drug concentrations were taken into account, the A150 +V80 combination had a synergistic effect on renin release. The A150+V80 combination lowered BP at least as effectively as either higher dose monotherapy. In conclusion, in mildly sodium-depleted normotensive individuals, the long-lasting effects of aliskiren alone or in combination with valsartan on plasma immunoreactive active renin and urinary aldosterone effects demonstrate strong and prolonged blockade of angiotensin II at the kidney and the adrenal level. Moreover, a renin inhibitor and AT1R antagonist combination may provide synergistic effects on RAS hormone levels.

Safety and systemic absorption of pulmonary delivered human IFN-beta1a in the nonhuman primate: comparison with subcutaneous dosing.

Safety and bioavailability of pulmonary delivered interferon-beta 1a (IFN-beta1a, AVONEX, Biogen, Inc., Cambridge, MA) was evaluated in the nonhuman primate. Pulmonary bioavailability following intratracheal (i.t.) instillation of 50 microg/kg IFN-beta1a to rhesus macaques was approximately 10%. To evaluate pulmonary safety, IFN-beta1a was administered intrabronchially to rhesus and cynomolgus macaques at a dose of 60 microg/dose one, three, or seven times per week for 4 weeks. At scheduled termination, lungs were evaluated for gross and histomorphologic changes. IFN-beta1a or vehicle (human serum albumin [HSA] in phosphate-buffered saline [PBS]) treatment resulted in minimal to mild subchronic alveolitis, located primarily near the instillation sites. These responses were considered nonspecific and consistent with either instillation of a foreign protein or minor injury associated with the instillation procedure. In one rhesus macaque treated every day for 4 weeks, IFN-beta1a induced mild to moderate eosinophilic alveolitis, considered possibly an isolated type I hypersensitivity response to HSA or IFN-beta1a. Partial resolution of pulmonary lesions was seen in all recovery animals killed 2 weeks after cessation of treatment. In conclusion, this study shows that pulmonary administration of human IFN-beta1a is safe and that the pulmonary route of administration is a possible alternate route for the systemic delivery of IFN-beta1a.