A Melanocortin-4 Receptor Agonist Induces Skin and Hair Pigmentation in Patients with Monogenic Mutations in the Leptin-Melanocortin Pathway.

BACKGROUND AND OBJECTIVES: Gene mutations within the leptin-melanocortin signaling pathway lead to severe early-onset obesity. Recently, a phase 2 trial evaluated new pharmacological treatment options with the MC4R agonist setmelanotide in patients with mutations in the genes encoding proopiomelanocortin (POMC) and leptin receptor (LEPR). During treatment with setmelanotide, changes in skin pigmentation were observed, probably due to off-target effects on the closely related melanocortin 1 receptor (MC1R). Here, we describe in detail the findings of dermatological examinations and measurements of skin pigmentation during this treatment over time and discuss the impact of these changes on patient safety. METHODS: In an investigator-initiated, phase 2, open-label pilot study, 2 patients with loss-of-function POMC gene mutations and 3 patients with loss-of-function variants in LEPR were treated with the MC4R agonist setmelanotide. Dermatological examination, dermoscopy, whole body photographic documentation, and spectrophotometric measurements were performed at screening visit and approximately every 3 months during the course of the study. RESULTS: We report the results of a maximum treatment duration of 46 months. Skin pigmentation increased in all treated patients, as confirmed by spectrophotometry. During continuous treatment, the current results indicate that elevated tanning intensity levels may stabilize over time. Lips and nevi also darkened. In red-haired study participants, hair color changed to brown after initiation of setmelanotide treatment. DISCUSSION: Setmelanotide treatment leads to skin tanning and occasionally hair color darkening in both POMC- and LEPR-deficient patients. No malignant skin changes were observed in the patients of this study. However, the results highlight the importance of regular skin examinations before and during MC4R agonist treatment.

MC4R agonism promotes durable weight loss in patients with leptin receptor deficiency.

Genetic defects underlying the melanocortin-4 receptor (MC4R) signaling pathway lead to severe obesity. Three severely obese LEPR-deficient individuals were administered the MC4R agonist setmelanotide, resulting in substantial and durable reductions in hyperphagia and body weight over an observation period of 45-61 weeks. Compared to formerly developed and tested MC4R agonists, setmelanotide has the unique capability of activating nuclear factor of activated T cell (NFAT) signaling and restoring function of this signaling pathway for selected MC4R variants. Our data demonstrate the potency of setmelanotide in treatment of individuals with diverse MC4R-related pathway deficiencies.

Melanocortin 4 Receptor Pathway Dysfunction in Obesity: Patient Stratification Aimed at MC4R Agonist Treatment.

Context: The hypothalamic melanocortin 4 receptor (MC4R) pathway serves a critical role in regulating body weight. Loss of function (LoF) mutations in the MC4R pathway, including mutations in the pro-opiomelanocortin (POMC), prohormone convertase 1 (PCSK1), leptin receptor (LEPR), or MC4R genes, have been shown to cause early-onset severe obesity. Methods: Through a comprehensive epidemiological analysis of known and predicted LoF variants in the POMC, PCSK1, and LEPR genes, we sought to estimate the number of US individuals with biallelic MC4R pathway LoF variants. Results: We predict ~650 α-melanocyte-stimulating hormone (MSH)/POMC, 8500 PCSK1, and 3600 LEPR homozygous and compound heterozygous individuals in the United States, cumulatively enumerating >12,800 MC4R pathway-deficient obese patients. Few of these variants have been genetically diagnosed to date. These estimates increase when we include a small subset of less rare variants: ß-MSH/POMC,PCSK1 N221D, and a PCSK1 LoF variant (T640A). To further define the MC4R pathway and its potential impact on obesity, we tested associations between body mass index (BMI) and LoF mutation burden in the POMC, PCSK1, and LEPR genes in various populations. We show that the cumulative allele burden in individuals with two or more LoF alleles in one or more genes in the MC4R pathway are predisposed to a higher BMI than noncarriers or heterozygous LoF carriers with a defect in only one gene. Conclusions: Our analysis represents a genetically rationalized study of the hypothalamic MC4R pathway aimed at genetic patient stratification to determine which obese subpopulations should be studied to elucidate MC4R agonist (e.g., setmelanotide) treatment responsiveness.

Evaluation of a melanocortin-4 receptor (MC4R) agonist (Setmelanotide) in MC4R deficiency.

OBJECTIVE: Pro-opiomelanocortin (POMC)-derived peptides act on neurons expressing the Melanocortin 4 receptor (MC4R) to reduce body weight. Setmelanotide is a highly potent MC4R agonist that leads to weight loss in diet-induced obese animals and in obese individuals with complete POMC deficiency. While POMC deficiency is very rare, 1-5% of severely obese individuals harbor heterozygous mutations in MC4R. We sought to assess the efficacy of Setmelanotide in human MC4R deficiency. METHODS: We studied the effects of Setmelanotide on mutant MC4Rs in cells and the weight loss response to Setmelanotide administration in rodent studies and a human clinical trial. We annotated the functional status of 369 published MC4R variants. RESULTS: In cells, we showed that Setmelanotide is significantly more potent at MC4R than the endogenous ligand alpha-melanocyte stimulating hormone and can disproportionally rescue signaling by a subset of severely impaired MC4R mutants. Wild-type rodents appear more sensitive to Setmelanotide when compared to MC4R heterozygous deficient mice, while MC4R knockout mice fail to respond. In a 28-day Phase 1b clinical trial, Setmelanotide led to weight loss in obese MC4R variant carriers. Patients with POMC defects upstream of MC4R show significantly more weight loss with Setmelanotide than MC4R deficient patients or obese controls. CONCLUSIONS: Setmelanotide led to weight loss in obese people with MC4R deficiency; however, further studies are justified to establish whether Setmelanotide can elicit clinically meaningful weight loss in a subset of the MC4R deficient obese population.

Efficacy and Safety of Relamorelin in Diabetics With Symptoms of Gastroparesis: A Randomized, Placebo-Controlled Study.

BACKGROUND & AIMS: Gastroparesis is a complication of diabetes with few treatment options. Relamorelin (also referred to as RM-131) is a selective, prokinetic agonist of ghrelin. We aimed to evaluate the efficacy of relamorelin on symptoms and gastric emptying (GE) in a 12-week, phase 2B study of diabetic patients with moderate to severe gastroparesis symptoms (DG). METHODS: We performed a study of 393 patients with DG (37.7% male; 9.9% with type 1 diabetes; median age, 58.2 years [range 20-76]; median body mass index, 31.4 kg/m2 [range, 18.2-60.1]; HbA1c level, 7.6%, [range, 5.2-11.0]). All participants had 13C-spirulina GE breath test T1/2 values of 79 minutes or more (with 89.8% delayed relative to 90th %ile of normal, 85.75 minutes), recent vomiting, and gastroparesis cardinal symptom index-daily diary scores of 2.6 or more. Patients were randomly assigned to groups given placebo (n=104) or relamorelin (10 µg [n=98], 30 µg [n=109], or 100 µg [n=82] twice daily) for 12 weeks, following a 2-week, single-blind, placebo run-in period. Patient-reported outcomes were determined from DG Symptom Severity daily e-diaries, in which patients recorded vomiting frequency and symptom scores (nausea, abdominal pain, postprandial fullness, and bloating) on a 0-10 scale. Endpoints were change from baseline in vomiting frequency, composite DG Symptom Severity score, GE, and safety. We performed longitudinal, mixed-effects model analysis using repeated measures, with baseline and baseline-by-week interaction values as covariates. RESULTS: Patients given relamorelin had a 75% reduction in vomiting frequency compared with baseline, but this difference was not significant compared with the placebo group. All 4 symptoms of DG (composite or individual symptoms) were significantly reduced over the 12-week study period in all 3 relamorelin dose groups compared with the placebo group (all P < .05, based on longitudinal analysis over 12 weeks). Relamorelin significantly accelerated GE from baseline compared with placebo (by 12%, P < .05 for the 10 µg and 30 µg groups; P = .051 for the 100 µg group). Dose-related worsening of glycemic control was noted in 14.5% of patients who received relamorelin; some required insulin or other diabetes drug dosage adjustments. CONCLUSIONS: In a phase 2B randomized trial of patients with moderate to severe DG, relamorelin significantly reduced core symptoms of DG and overall composite score compared with placebo, accelerated GE, and was generally safe and well tolerated. ClinicalTrials.gov Identifier: NCT02357420.

Proopiomelanocortin Deficiency Treated with a Melanocortin-4 Receptor Agonist.

Patients with rare defects in the gene encoding proopiomelanocortin (POMC) have extreme early-onset obesity, hyperphagia, hypopigmentation, and hypocortisolism, resulting from the lack of the proopiomelanocortin-derived peptides melanocyte-stimulating hormone and corticotropin. In such patients, adrenal insufficiency must be treated with hydrocortisone early in life. No effective pharmacologic treatments have been available for the hyperphagia and obesity that characterize the condition. In this investigator-initiated, open-label study, two patients with proopiomelanocortin deficiency were treated with setmelanotide, a new melanocortin-4 receptor agonist. The patients had a sustainable reduction in hunger and substantial weight loss (51.0 kg after 42 weeks in Patient 1 and 20.5 kg after 12 weeks in Patient 2).

Relamorelin Reduces Vomiting Frequency and Severity and Accelerates Gastric Emptying in Adults With Diabetic Gastroparesis.

BACKGROUND & AIMS: Gastroparesis is an important complication of diabetes. We investigated the effects of relamorelin (a pentapeptide-selective agonist of the ghrelin receptor that speeds gastric emptying in patients with diabetes) in patients with diabetic gastroparesis. METHODS: We performed a double-blind trial of 204 patients (78% Caucasian; 67% female; mean age, 55 y; 88% with type 2 diabetes) with diabetic gastroparesis with moderate to severe symptoms and delayed gastric emptying at 27 clinical centers, from June 2012 until August 2013. Patients were assigned randomly (1:1:1) to groups given placebo or subcutaneous relamorelin 10 µg once or twice daily. The primary end point was the half-time of gastric emptying. Secondary end points included nausea, abdominal pain, bloating, early satiety, as well as the composite score of these 4 subjective symptoms and vomiting frequency and severity. RESULTS: Twice-daily relamorelin significantly accelerated gastric emptying (P < .03) and reduced vomiting frequency (by ∼60%) and severity vs placebo (P ≤ .033). Compared with placebo, relamorelin did not improve other gastrointestinal symptoms, such as abdominal pain and satiety. In the 119 patients (58.3%) with baseline vomiting, twice-daily relamorelin significantly reduced the half-time of gastric emptying and vomiting, as well as nausea, abdominal pain, bloating, and early satiety compared with placebo (composite score, P = .043). No overall safety concerns were identified. CONCLUSIONS: In a clinical trial of patients with diabetic gastroparesis, relamorelin (10 µg twice daily) significantly accelerated gastric emptying and significantly reduced vomiting, compared with placebo. Among patients with baseline vomiting, relamorelin had prokinetic effects and significantly reduced vomiting and also improved other symptoms of diabetic gastroparesis compared with placebo. ClincialTrials.gov number: NCT01571297.

Relamorelin Relieves Constipation and Accelerates Colonic Transit in a Phase 2, Placebo-Controlled, Randomized Trial.

BACKGROUND & AIMS: Ghrelin receptors are located in the colon. Relamorelin is a pentapeptide selective agonist of ghrelin receptor 1a with gastric effects, but its effects in the colon are not known. We aimed to evaluate the effects of relamorelin on bowel movements (BMs) and gastrointestinal and colonic transit (CT) in patients with chronic constipation. METHODS: We performed a study of 48 female patients with chronic constipation who fulfilled the Rome III criteria and had 4 or fewer spontaneous BMs (SBMs)/wk. In a randomized (1:1), double-blind, parallel-group, placebo-controlled trial, the effects of relamorelin (100 µg/d, given subcutaneously) were tested during 14 days after a 14-day baseline, single-blind phase in which patients were given placebo at 2 Mayo Clinic sites. The participants' mean age was 40.6 ± 1.5 y, with a mean body mass index of 25.7 ± 0.6 kg/m(2), with 1.7 ± 0.1 SBM/wk, and a mean stool consistency of 1.2 ± 0.1 on the Bristol scale during this baseline period. The effect of treatment on transit was measured in 24 participants with colonic transit of less than 2.4 (geometric center at 24 h) during the baseline period. Gastric emptying, small-bowel transit, and CT were measured during the last 2 days that patients received relamorelin or placebo. Bowel function was determined from daily diaries kept by patients from days 1 through 28. Study end points were time to first BM, SBMs/wk, complete SBMs/wk, stool form, and ease of stool passage. Effects of relamorelin were assessed by analysis of covariance. RESULTS: Compared with placebo, relamorelin accelerated gastric emptying half-time (P = .027), small-bowel transit (P = .051), and CT at 32 hours (P = .040) and 48 hours (P = .017). Relamorelin increased the number of SBMs (P < .001) and accelerated the time to first BM after the first dose was given (P = .004) compared with placebo, but did not affect stool form. Adverse events associated with relamorelin included increased appetite, fatigue, and headache. CONCLUSIONS: Relamorelin acts in the colon to significantly reduce symptoms of constipation and accelerate CT in patients with chronic constipation, compared with placebo. ClinicalTrial.Gov registration number: NCT01781104.

RM-493, a melanocortin-4 receptor (MC4R) agonist, increases resting energy expenditure in obese individuals.

CONTEXT: Activation of the melanocortin-4 receptor (MC4R) with the synthetic agonist RM-493 decreases body weight and increases energy expenditure (EE) in nonhuman primates. The effects of MC4R agonists on EE in humans have not been examined to date. OBJECTIVE, DESIGN, AND SETTING: In a randomized, double-blind, placebo-controlled, crossover study, we examined the effects of the MC4R agonist RM-493 on resting energy expenditure (REE) in obese subjects in an inpatient setting. STUDY PARTICIPANTS AND METHODS: Twelve healthy adults (6 men and 6 women) with body mass index of 35.7 ± 2.9 kg/m(2) (mean ± SD) received RM-493 (1 mg/24 h) or placebo by continuous subcutaneous infusion over 72 hours, followed immediately by crossover to the alternate treatment. All subjects received a weight-maintenance diet (50% carbohydrate, 30% fat, and 20% protein) and performed 30 minutes of standardized exercise daily. Continuous EE was measured on the third treatment day in a room calorimeter, and REE in the fasting state was defined as the mean of 2 30-minute resting periods. RESULTS: RM-493 increased REE vs placebo by 6.4% (95% confidence interval, 0.68-13.02%), on average by 111 kcal/24 h (95% confidence interval, 15-207 kcal, P = .03). Total daily EE trended higher, whereas the thermic effect of a test meal and exercise EE did not differ significantly. The 23-hour nonexercise respiratory quotient was lower during RM-493 treatment (0.833 ± 0.021 vs 0.848 ± 0.022, P = .02). No adverse effect on heart rate or blood pressure was observed. CONCLUSIONS: Short-term administration of the MC4R agonist RM-493 increases REE and shifts substrate oxidation to fat in obese individuals.

Inhibition of prostacyclin and thromboxane biosynthesis in healthy volunteers by single and multiple doses of acetaminophen and indomethacin.

This double-blind, randomized crossover study assessed the effect of acetaminophen (1000 mg every 8 hours) versus indomethacin (50 mg every 8 hours) versus placebo on cyclooxygenase enzymes (COX-1 and COX-2). Urinary excretion of 2,3-dinor-6-keto-PGF1α, (prostacyclin metabolite, PGI-M; COX-2 inhibition) and 11-dehydro thromboxane B2 (thromboxane metabolite, Tx-M; COX-1 inhibition) were measured after 1 dose and 5 days of dosing. Peak inhibition of urinary metabolite excretion across 8 hours following dosing was the primary end point. Mean PGI-M excretion was 33.7%, 55.9%, and 64.6% on day 1 and 49.4%, 65.1%, and 80.3% on day 5 (placebo, acetaminophen, and indomethacin, respectively). Acetaminophen and indomethacin inhibited PGI-M excretion following single and multiple doses (P = .004 vs placebo). PGI-M excretion inhibition after 1 dose was similar for indomethacin and acetaminophen, but significantly greater with indomethacin after multiple doses (P = .006). Mean Tx-M excretion was 16.2%, 45.2%, and 86.6% on day 1 and 46.2%, 58.4%, and 92.6% on day 5 (placebo, acetaminophen, and indomethacin, respectively). Tx-M excretion inhibition following 1 dose was reduced by acetaminophen (P ≤ .003). Indomethacin reduced Tx-M excretion significantly more than acetaminophen and placebo after single and multiple doses (P ≤ .001). Acetaminophen and indomethacin inhibited COX-1 and COX-2 following a single dose, but acetaminophen was a less potent COX-1 inhibitor than indomethacin.

Preclinical gastrointestinal prokinetic efficacy and endocrine effects of the ghrelin mimetic RM-131.

AIMS: The 28 amino acid hormone ghrelin, the natural ligand for the growth hormone secretagogue, or ghrelin receptor (GHR), has diverse physiological functions, including a possible role as a gastrointestinal prokinetic. The synthetic ghrelin mimetic RM-131 is in Phase II clinical trials for treatment of diabetic gastroparesis and other gastrointestinal (GI) disorders. We aimed to determine the relative potency of RM-131, when compared to other GI ghrelin mimetics, to predict efficacy and determine the role of RM-131 in models of inflammatory bowel disease. MAIN METHODS: We evaluated and compared ghrelin, RM-131 and other synthetic ghrelin mimetics for their prokinetic potency in models of gastrointestinal disorders in the rat and we evaluated the endocrine (rats and dogs) and anti-inflammatory effects (mice) of the ghrelin mimetic RM-131. KEY FINDINGS: The pentapeptide RM-131 increased gastric emptying in rodent models of ileus. RM-131 is about 100-fold more potent than human ghrelin and is 600 to 1800-fold more potent, when compared to several investigational ghrelin mimetics tested in clinical trials. RM-131 has anti-inflammatory effects and significantly increases survival and reduces macroscopic markers of tissue damage in a TNBS model of inflammatory bowel disease. RM-131 treatment shows a transient increase in growth hormone levels in Beagle dogs and rats, returning to baseline upon chronic treatment. Significant effects on glucose and insulin are not observed in chronic studies. SIGNIFICANCE: RM-131's potency, efficacy and endocrine profile, are promising attributes for the treatment of diverse functional gastrointestinal disorders in humans.

Diary of hot flashes reported upon occurrence: results of a randomized double-blind study of raloxifene, placebo, and paroxetine.

OBJECTIVE: This trial examined diaries of hot flash events reported upon occurrence to assess the test/retest reliability of the diaries and their ability to measure treatment effects on hot flash frequency and severity. METHODS: Forty-two postmenopausal women (aged ≥40 y; 5-50 hot flashes/wk) were randomized (3:3:1) to placebo, raloxifene 60 mg, or paroxetine 20 mg daily for 12 weeks. Diaries of hot flash frequency and severity were evaluated at 1-week intervals (twice before study treatment and thrice during study treatment). RESULTS: Forty-one women were evaluated. Baseline characteristics were similar between groups (eg, mean, 29.8 hot flashes/wk). Concordance correlation coefficients between screening (week -2) and baseline (week -1) measures of hot flash frequency and severity were 0.73 and 0.71, respectively. After 12 weeks, the mean (95% CI) percent changes from baseline in weekly hot flash frequency were as follows: placebo, -37.4% (-60.9 to -14.0); raloxifene, -14.2% (-37.7 to 9.3); paroxetine, -49.8% (-88.6 to -11.0); the mean (95% CI) percent changes in hot flash severity were as follows: placebo, -39.9% (-69.1 to -10.8); raloxifene, -9.6% (-38.8 to 19.6); paroxetine, -36.6% (-84.7 to 11.5). There were no significant differences in hot flash diary results between treatment groups. CONCLUSIONS: Measures of hot flash frequency and severity show acceptable test/retest reliability between screening and baseline. Reductions in vasomotor symptoms by raloxifene are numerically less than those seen with placebo, but no statistically significant treatment differences have been documented in this small study. The large effect of placebo and the significant reduction in vasomotor symptoms by paroxetine are consistent with other studies. The diary seems to be suitable for use in hot flash clinical trials.

Pharmacokinetic-pharmacodynamic studies of the 11ß-hydroxysteroid dehydrogenase type 1 inhibitor MK-0916 in healthy subjects.

AIMS: To characterize pharmacokinetic parameters of MK-0916 and its safety and tolerability in lean, healthy male subjects following single and multiple oral doses. To assess (by stable-isotope labelling) the in vivo inhibition of cortisone-to-cortisol conversion following oral MK-0916. METHODS: Data are presented from two randomized, controlled, double-blind, rising-dose phase I studies. In the first study, subjects received single oral doses of 0.4-100 mg MK-0916 (n = 16). In the second study, subjects received 0.2-225 mg MK-0916 followed by daily doses of 0.2-100 mg for 13 days beginning on day 2 or day 15 (n = 80). Plasma and urine drug concentrations were measured for pharmacokinetic analysis. For pharmacodynamic analysis, concentrations of plasma [(13)C4]cortisol were measured by high-pressure liquid chromatography and tandem mass spectrometry following a single oral dose of 5 mg [(13)C4]cortisone. RESULTS: Doses ≥3 mg were rapidly absorbed (time at which maximal concentration was achieved in plasma, 1.1-1.8 h). Exposure (measured as the area under the concentration-time curve from 0 to 168 h) increased approximately in proportion to dose. Values for the maximal plasma concentration and the plasma concentration at 24 h increased in excess of dose proportionality at doses <6 mg and roughly in proportion to dose at doses >6 mg. In subjects dosed with 6 mg MK-0916 once daily for 14 days, the mean trough plasma concentration was 240 nm and in vivo cortisone-to-cortisol conversion was inhibited by 84%. The relationship between plasma MK-0916 and hepatic 11ß-hydroxysteroid dehydrogenase type 1 inhibition was well represented by a simple Emax model with an IC50 of 70.4 nm. Exposure to MK-0916 was generally well tolerated. CONCLUSIONS: These findings indicate that 11ß-hydroxysteroid dehydrogenase type 1 is effectively inhibited in human subjects by doses of MK-0916 that are well tolerated.

Randomized controlled phase Ib study of ghrelin agonist, RM-131, in type 2 diabetic women with delayed gastric emptying: pharmacokinetics and pharmacodynamics.

OBJECTIVE: To investigate the pharmacokinetics (PK), pharmacodynamics, and safety of single-dose RM-131 in type 2 diabetic patients with gastrointestinal cardinal symptoms (GCSI) and previously documented delayed gastric emptying (DGE). RESEARCH DESIGN AND METHODS: In a randomized crossover study, 10 female patients received RM-131 (100 µg s.c.) or placebo and underwent scintigraphic gastric emptying (GE) and colonic filling at 6 h (CF6) of a solid-liquid meal administered 30 min postdosing. Adverse events, plasma glucose, and hormonal levels were assessed. GCSI daily diary (GCSI-DD) was completed during treatments. PK was assessed in this cohort and healthy volunteers (HVs). RESULTS: At screening, HbA(1c) was 7.2 ± 0.4% (SEM) and total GCSI-DD score was 1.32 ± 0.21. RM-131 accelerated GE t(1/2) of solids (P = 0.011); mean difference (Δ) in solid GE t(1/2) was 68.3 min (95% CI 20-117) or 66.1%. There were numerical differences in GE lag time, CF6 solids, and GE t(1/2) liquids (all P < 0.14). With a significant (P < 0.014) order effect, further analysis of the first treatment period (n = 5 per group) confirmed significant RM-131 effects on GE t(1/2) (solids, P = 0.016; liquids, P = 0.024; CF6, P = 0.013). PK was similar in DGE patients and HVs. There were increases in 120-min blood glucose (P = 0.07) as well as 30-90-min area under the curve (AUC) levels of growth hormone, cortisol, and prolactin (all P < 0.02) with single-dose RM-131. Only light-headedness was reported more on RM-131. CONCLUSIONS: RM-131 greatly accelerates the GE of solids in patients with type 2 diabetes and documented DGE. PK is similar in diabetic patients and HVs.

Efficacy and safety of boceprevir plus peginterferon-ribavirin in patients with HCV G1 infection and advanced fibrosis/cirrhosis.

BACKGROUND & AIMS: We assessed the safety and efficacy of boceprevir (BOC) plus peginterferon-ribavirin (PR) in patients with HCV-G1 infection and advanced fibrosis/cirrhosis (Metavir F3/F4). METHODS: In two randomized controlled studies of previously untreated and previous treatment failures, patients received a 4-week lead-in of PR followed by PR plus placebo for 44 weeks (PR48); PR plus BOC using response guided therapy (BOC/RGT); or PR plus BOC for 44 weeks (BOC/PR48). RESULTS: The trials enrolled 178 patients with F3/4. HCV RNA levels at week 4 and 8 were highly predictive of response. No patient with F3/4 in the PR48 arm with a <1 log(10) decline in HCV RNA at week 4 achieved SVR, whereas those randomized to BOC/RGT or BOC/PR48 had SVR rates of 11-33% (F3) and 10-14% (F4). In these latter groups, patients with high baseline viral load (>2 × 10(6)IU/ml) had an overall SVR rate of 6% (2/33). For patients with a ≥1 log(10) decline at week 4, SVR rates in the BOC/PR48 arm of SPRINT-2 and RESPOND-2, respectively, were 77% and 87% vs. 18% and 50% for PR48; SVR rates in early responders (undetectable HCV RNA at week 8) were 90-93% in the BOC/PR48 arm. Neutropenia and thrombocytopenia were more common in cirrhotics than non-cirrhotics. CONCLUSIONS: BOC improves SVR rates in patients with F3/4, and longer treatment duration provides the most benefit. With triple therapy, SVR rates are modest in F4 patients with a <1 log(10) decline at week 4, thus the 4-week PR lead-in aids in the assessment of early futility.

Odanacatib, a selective cathepsin K inhibitor to treat osteoporosis: safety, tolerability, pharmacokinetics and pharmacodynamics--results from single oral dose studies in healthy volunteers.

AIMS: To evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of odanacatib (ODN), a cathepsin K inhibitor, in humans. METHODS: Two double-blind, randomized, placebo-controlled, single oral dose studies were performed with ODN (2-600 mg) in 44 healthy volunteers (36 men and eight postmenopausal women). RESULTS: Adverse experiences (AEs) with single doses of ODN were transient and mild to moderate, with the exception of one severe AE of gastroenteritis. Headache was the most frequent AE. After absorption of ODN (initial peak concentrations 4-6 h postdose), plasma concentrations exhibited a monophasic decline, with an apparent terminal half-life of ∼40-80 h. The area under the curve0-24 hours (AUC(0-24 h)), concentration at 24 hours (C(24 h)) and maximum concentration (C(max,overal)) increased in a less than dose-proportional manner from 2 to 600 mg. Administration of ODN with a high-fat meal led to ∼100% increases in AUC(0-24 h), C(max,day1), C(max,overall) and C(24 h) relative to the fasted state, while administration with a low-fat meal led to a ∼30% increase in those parameters. Reduction of biomarkers of bone resorption, the C- and N-telopeptides of cross-links of type I collagen, (CTx and NTx, respectively), was noted at 24 h for doses ≥5 mg and at 168 h postdose for ≥10 mg. In postmenopausal women administered 50 mg ODN, reductions in serum CTx of -66% and urine NTx/creatinine (uNTx/Cr) of -51% relative to placebo were observed at 24 h. At 168 h, reductions in serum CTx (-70%) and uNTx/Cr (-78%) were observed relative to baseline. Pharmacokinetic/pharmacodynamic modeling characterized the ODN concentration/uNTx/Cr relation, with a modeled EC50 value of 43.8 nM and ∼80% maximal reduction. CONCLUSIONS: Odanacatib was well tolerated and has a pharmacokinetic and pharmacodynamic profile suitable for once weekly dosing.

Quantifying monocyte infiltration in response to intradermal tetanus toxoid injection.

AIMS: To characterize monocyte response in a delayed-type hypersensitivity reaction to intradermal tetanus toxoid (TT) injection. MATERIALS & METHODS: Men with positive serum anti-tetanus titers were stratified by last TT vaccination. Subjects were administered three intradermal injections of TT and one saline control on the same side of the back. Skin biopsies were taken post-injection. After 2 weeks, the procedure was repeated on the contralateral side. RESULTS: Men who received TT booster vaccination 1 month before the study showed greater reproducibility and lower variability in monocyte responses than those who were not revaccinated. Monocyte concentration in subjects re-vaccinated within 1 month of study start appeared maximal at 48 h post-injection. CONCLUSION: This assay represents a novel approach that allows for quantification of dermal monocyte/macrophage influx. This clinical methodology has potential utility in the pharmacodynamic evaluation of therapies targeting inflammatory disorders, which involve monocyte tissue recruitment, like the delayed-type hypersensitivity response.

Refinement of stopping rules during treatment of hepatitis C genotype 1 infection with boceprevir and peginterferon/ribavirin.

UNLABELLED: In comparison with peginterferon/ribavirin alone, boceprevir with peginterferon/ribavirin significantly improves sustained virological response (SVR) rates in patients with chronic hepatitis C virus (HCV) genotype 1 infections, but treatment failure remains a significant problem. Using phase 3 trial databases, we sought to develop stopping rules for patients destined to fail boceprevir-based combination therapy in order to minimize drug toxicity, resistance, and costs in the face of ultimate futility. Exploratory post hoc analyses using data from the Serine Protease Inhibitor Therapy 2 (SPRINT-2) study (treatment-naive patients) and the Retreatment With HCV Serine Protease Inhibitor Boceprevir and Pegintron/Rebetol 2 (RESPOND-2) study (treatment-experienced patients) were undertaken to determine whether protocol-specified stopping rules (detectable HCV RNA at week 24 for SPRINT-2 and at week 12 for RESPOND-2) could be refined and harmonized. In SPRINT-2, a week 12 rule with an HCV RNA cutoff of ≥ 100 IU/mL would have discontinued therapy in 65 of 195 failures (sensitivity = 33%) without sacrificing a single SVR among 475 successes (specificity = 100%). Viral variants emerged after week 12 in 36 of the 49 evaluable patients (73%) who would have discontinued at week 12 using a ≥ 100 IU/mL stopping rule. In RESPOND-2, five of six patients with week 12 HCV RNA levels between the lower limit of detection (9.3 IU/mL) and the lower limit of quantification (25 IU/mL) who continued therapy despite the protocol-stipulated futility rule achieved SVR; one additional patient with a week 12 HCV RNA level of 148 IU/mL also continued therapy, had undetectable HCV RNA at week 16, and attained SVR. CONCLUSION: Although a stopping rule of detectable HCV RNA at week 12 would have forfeited some SVR cases, week 12 HCV RNA levels ≥ 100 IU/mL almost universally predicted a failure to achieve SVR in both treatment-naive and treatment-experienced patients. In boceprevir recipients, the combination of 2 stopping rules-an HCV RNA level ≥ 100 IU/mL at week 12 and detectable HCV RNA at week 24--maximized the early discontinuation of futile therapy and minimized premature treatment discontinuation.

Raltegravir: the first HIV-1 integrase strand transfer inhibitor in the HIV armamentarium.

Raltegravir is the first integrase strand transfer inhibitor approved for the treatment of HIV-1 infection. As the first agent in this new class of antiretroviral therapies, raltegravir has demonstrated safety and efficacy in treatment-naive as well as heavily pretreated HIV-infected patients failing therapy with multidrug-resistant virus. Raltegravir has a favorable drug interaction profile that permits both administration to a wide, demographically diverse patient population and coadministration with many other therapeutic agents, including antiretroviral agents and supportive medications, without restrictions or dose adjustment. Data through 96 weeks of follow-up in three phase III studies, protocol 021 (STARTMRK) in treatment-naive patients, and protocols 018 (BENCHMRK-1) and 019 (BENCHMRK-2) in treatment-experienced patients, demonstrated the potent and durable antiretroviral and immunologic effects and the favorable long-term safety profile of raltegravir in both treatment-naive and treatment-experienced patients. Raltegravir represents an important addition to the current armamentarium for the treatment of HIV infection.

Effect of a novel histamine subtype-3 receptor inverse agonist and modafinil on EEG power spectra during sleep deprivation and recovery sleep in male volunteers.

RATIONALE: Histamine and dopamine contribute to the maintenance of wakefulness. OBJECTIVE: This study aims to conduct an exploratory analysis of the effects of 10 and 50 mg of MK-0249, a novel histamine subtype-3 receptor inverse agonist, and 200 mg of modafinil, a presumed dopaminergic compound, on EEG power spectra during sleep deprivation and subsequent recovery sleep. METHODS: A total of 25 healthy men were recruited to a double-blind, placebo-controlled cross-over design. EEG power spectra, an electrophysiological marker of changes in sleepiness and vigilance, were obtained at the beginning of wake maintenance tests at two-hourly intervals throughout a night and day of sleep deprivation, which is an established model of excessive sleepiness. RESULTS: After placebo, sleep deprivation was associated with enhancements in delta and theta and reductions in alpha and beta activity. Following dosing at 02:00 h, MK-0249 and modafinil reduced delta and theta activity and enhanced alpha and beta activity, compared to placebo. During recovery sleep initiated at 21:00 h, latency to sleep onset and number of awakenings were not different from placebo for any of the active treatments. Wake after sleep onset and stage 1% was increased and total sleep time, SWS% and REM% were reduced after both doses of MK-0249. Compared to placebo, MK-0249, the 50-mg dose in particular, reduced activity in some delta and theta/alpha frequencies and enhanced beta activity during NREM sleep and REM sleep. After modafinil, no changes were observed for power spectra during sleep. CONCLUSION: Both MK-0249 and modafinil exert effects on the EEG which are consistent with wake promotion.