POS0135 REDUCING IMMUNOGENICITY OF PEGLOTICASE (RECIPE) WITH CONCOMITANT USE OF MYCOPHENOLATE MOFETIL IN PATIENTS WITH REFRACTORY GOUT: A PHASE II RANDOMIZED CONTROLLED TRIAL

Background:

Pegloticase is a recombinant, pegylated uricase, used for treatment of gout patients who fail oral urate lowering therapy (ULT). Its use has been limited due to immunogenicity leading to infusion reactions.1

Objectives:

We evaluated if co-administration of an immunomodulatory agent could prolong the efficacy of pegloticase.

Methods:

Participants were recruited in a Phase II, double-blind, placebo-controlled trial over 18 months and randomized in a 3:1 ratio by site. Inclusion criteria were: a) Age ≥ 18 years who met 2015 ACR/EULAR gout classification criteria and b) chronic refractory gout defined as symptoms inadequately controlled with ULT or contraindications. After a 2-week run-in of mycophenolate mofetil (MMF) 1000 mg twice daily or matching placebo (PBO), they received a combination of pegloticase 8 mg biweekly with MMF or PBO for 12 weeks. Subsequent to this MMF or PBO were discontinued but pegloticase was continued for another 12 weeks. The primary endpoint was proportion of patients who sustained a serum urate (SU) level of ≤ 6 mg/dl at 12 weeks. Secondary endpoints included 24-week durability of SU ≤ 6 mg/dl and rate of adverse events (AEs). Fisher’s exact test and Wilcoxon two-sample test were used for analyses along with Kaplan-Meier estimates and log-rank tests to compare survival curves between groups. Hypothesis tests were two-tailed and p-value (p) < 0.05 indicated statistical significance.

Results:

Of 42 subjects screened, 35 were randomized, and 32 who received at least one dose of pegloticase were included in modified intention to treat analyses. Subjects were predominantly men (88%), mean age of 55.2 years (SD=9.7). Mean duration of gout was 13.4 years (SD=9.0), mean baseline sUA was 9.2 mg/dL (SD=1.6). Tophi were present in 88% and majority were on optimized ULT - 59% on allopurinol and 16% on febuxostat, with 63% reporting > 1 flare in the past year. At baseline both arms (MMF vs. PBO) had similar comorbidities – (82% vs 70%), diabetes mellitus/metabolic syndrome (14% vs 20%), coronary artery disease/peripheral vascular disease (41% vs.70%), BMI>30 (86% vs. 90%) and renal insufficiency (defined as eGFR < 90 mL/min; 73% vs. 70%). At 12 weeks, 19 of 22 (86%) in the MMF arm achieved SU ≤ 6 mg/dl compared to 4 of 10 (40%) in PBO arm (p-value = 0.01). At 24 weeks, the SU was ≤ 6 mg/dl in 68% of MMF arm vs. 30% in PBO (p-value = 0.06), and rates of AEs per month were similar between groups with the PBO arm having more infusion reactions (30% vs. 0%). The MMF arm had higher AEs compared to placebo: musculoskeletal (41% vs. 10%), gastrointestinal (18% vs. 10%), and infections (9% vs. 0%). Figure 1 shows that the percentage of subjects maintaining a sUA < 6 mg/dL at 12 weeks was significantly higher (p=0.02) in the MMF arm, and a significant difference (p=0.03) at 24 weeks indicates sustained benefit from MMF.

Conclusion:

To our knowledge this is the first randomized-controlled proof of concept trial to demonstrate the ability of an immunomodulatory agent in prolonging the efficacy of pegloticase. Short-term concomitant use of MMF therapy with pegloticase was well tolerated and showed a clinically meaningful improvement in the targeted SU ≤6 mg/dL at 12 and 24 weeks. This study suggests an innovative approach to utilize pegloticase therapy in patients with chronic gout.

References:

[1]Sundy et al. Efficacy and tolerability of pegloticase for the treatment of chronic gout in patients refractory to conventional treatment: two randomized controlled trials. JAMA. 2011;306(7):711-20.

Figure 1.

Proportion of subjects maintaining serum urate (SU) ≤ 6 mg/dL over 24 week study period in mycophenolate mofetil + pegloticase vs. placebo + pegloticase

Disclosure of Interests:

Puja Khanna Consultant of: Horizon Pharmaceuticals, Swedish Orphan Biovitrum A, Grant/research support from: Selecta, 2)DYVE, Dinesh Khanna Consultant of: Horizon Pharmaceuticals, Gary Cutter: None declared, Jeff Foster: None declared, Josh Melnick: None declared, Sara Jaafar: None declared, Stephanie Biggers: None declared, Fazlur Rahman: None declared, Hui-Chen Kuo: None declared, Michelle Feese: None declared, Kenneth Saag Consultant of: AbbVie, Inc., Bayer, Daiichi Sankyo Company LTD, Gilead Services, Inc., Horizon Pharma plc, Mallinkrodt, Radius Health, Inc., Roche/Genentech, Shanton Pharma Co., LTD, Teijin, Dyve Bioscience, LG Chem, Regeneron Pharmaceuticals., Swedish Orphan Biovitrum AB, Takeda Pharmaceuticals America, Inc.,

521 Prevalence and Impact of Restless Legs in Patients with Myasthenia Gravis

Introduction

Restless legs syndrome (RLS) is a sensori-motor disorder characterized by an urge to move the limbs during inactivity alleviated at least partially by walking/stretching. By contrast, myasthenia gravis (MG) is a neuromuscular disease with fluctuating weakness aggravated by continued muscle activity. Only a few studies addressed the prevalence of RLS in MG patients with limitations related to small sample size and/or usage of non-validated RLS screening tools. The aim of this study was to revisit the prevalence and impact of RLS in a large sample of MG patients using the validated 13-item short-form Cambridge-Hopkins diagnostic questionnaire for RLS (CH-RLSq13).

Methods

The MG foundation of America patient registry was used to survey MG patients. Only patients aged ≥18 years, residing in the USA, and who answered “yes” to the question “Has your doctor diagnosed you with MG?” were included in this study. A survey including the CH-RLSq13, demographic information, disease related history, and patient reported outcomes including the MG15-item Quality of Life (MG-QOL15) and the MG-Activities of Daily Living (MG-ADL) instruments was sent to MG registry participants as part of the semi-annual follow up.

Results

A total of 630 MG patients (age: 62.8±13.2; 54.9% Women; 94.6% White) completed the survey and met eligibility criteria (22% of patients receiving the survey). The prevalence of RLS was 14.8% (93/630). Clinically significant RLS (moderately/extremely distressing RLS ≥2–3 days/week) was present in 53 (8.4%) MG patients. MG patients with (versus without) RLS were significantly younger (p=0.0061), more women (p=0.0440), with higher (worse) depression (p&lt;0.0001), MG-ADL (p=0.0001), and MG-QOL15 (p&lt;0.0001) scores.

Conclusion

Clinically significant RLS is prevalent in MG patients and is associated with a negative impact on mood, daily activities, and quality of life. Therefore, from a clinical practice it seems warranted to screen for RLS in MG patients.

Support (if any)

This study was not funded.

Reducing Immunogenicity of Pegloticase With Concomitant Use of Mycophenolate Mofetil in Patients With Refractory Gout: A Phase II, Randomized, Double-Blind, Placebo-Controlled Trial

OBJECTIVE

Pegloticase is used for the treatment of severe gout, but its use is limited by immunogenicity. This study was undertaken to evaluate whether mycophenolate mofetil (MMF) prolongs the efficacy of pegloticase.

METHODS

Participants were randomized 3:1 to receive 1,000 mg MMF twice daily or placebo for 14 weeks, starting 2 weeks before receiving pegloticase and continuing while receiving intravenous pegloticase 8 mg biweekly for 12 weeks. Participants then received pegloticase alone from week 12 to week 24. The primary end points were the proportion of patients who sustained a serum urate level of ≤6 mg/dl at 12 weeks and the rate of adverse events (AEs). Secondary end points included 24-week durability of serum urate level ≤6 mg/dl. Fisher's exact test and Wilcoxon's 2-sample test were used for analyses, along with Kaplan-Meier estimates and log rank tests.

RESULTS

A total of 32 participants received ≥1 dose of pegloticase. Participants were predominantly men (88%), with a mean age of 55.2 years, mean gout duration of 13.4 years, and mean baseline serum urate level of 9.2 mg/dl. At 12 weeks, a serum urate level of ≤6 mg/dl was achieved in 19 (86%) of 22 participants in the MMF arm compared to 4 (40%) of 10 in the placebo arm (P = 0.01). At week 24, the serum urate level was ≤6 mg/dl in 68% of MMF-treated patients versus 30% of placebo-treated patients (P = 0.06), and rates of AEs were similar between groups, with more infusion reactions occurring in the placebo arm (30% versus 0%).

CONCLUSION

Our findings indicate that MMF therapy with pegloticase is well tolerated and shows a clinically meaningful improvement in targeted serum urate level of ≤6 mg/dl at 12 and 24 weeks. This study suggests an innovative approach to pegloticase therapy in gout.

Gender differences in prednisone adverse effects: Survey result from the MG registry

Objective

Prednisone is a first-line immunosuppressive treatment for myasthenia gravis (MG), whereas short-term and long-term adverse effects (AEs) are a limiting factor in its usage.

Method

The MG patient registry is a patient-driven, nation-wide database with patients of age ≥18 years, who were diagnosed with MG and live in the United States. Custom-designed "prednisone-steroid use and MG" survey was sent out to MG registry participants as part of semi-annual follow-up. Data were collected and analyzed for frequency.

Results

A total of 398 MG participants (21% response rate) completed the survey, including 173 men and 225 women. Among them, 298 reported current (174) or past (288) prednisone intake. Current prednisone dosage varied from 0.5 to 75 mg (median 10 mg, IQR 7-20), dosing frequency was daily in 132 (76%) and every other day in 31 (18%). Peak prednisone dose was commonly between 25 mg and 60 mg (Median 50 mg, IQR 25-60); however, doses more than 60 mg daily were reported in 59 (20%). Prednisone AEs were reported more commonly in women (95% vs 81%, p < 0.0001). Women reported more intolerable AEs (77% vs 50%, p < 0.00001) and less willingness to accept a dose increase (26% vs 44%, p = 0.03) compared with men.

Conclusions

Prednisone is commonly used in the treatment of MG, with highly variable dosages and dosing frequencies reflecting the absence of a standard guideline. Intolerable AEs were more commonly reported among women and was associated with unwillingness to accept a dose increase. Consensus guidelines and their validation are required to guide prednisone treatment for MG.

Body mass index and dietary intake among Head Start children and caregivers

BACKGROUND

The US Head Start program serves low-income preschoolers and their caregivers and provides an opportunity for assessment and intervention on obesity. We sought to determine the prevalence of obesity among children and their caregivers and to identify variables that are associated with child body mass index (BMI) z scores and caregiver BMI.

DESIGN/SETTING

Cross-sectional data on diet and BMI from 770 caregiver-child dyads recruited from 57 Head Start centers in Alabama and Texas.

METHODS

Height and weight of each caregiver and child were measured using standardized protocols. Dietary intakes of caregiver-child dyads were collected using three 24-hour dietary recalls and Block food frequency questionnaires. Data were collected between September 2004 and November 2005. The larger Food Pyramid categories were divided into 17 food consumption groups and tested for their association with child BMI z scores. Analysis of variance was used to test if food groups were significantly associated with child BMI z score.

RESULTS

The prevalence of obesity among children was 18.4%, 24.3%, and 37.3% among black, Hispanic, and white children, respectively (P<0.0001), whereas it was 58.3%, 41.4%, and 41.6% among black, Hispanic, and white caregivers, respectively (P<0.0001). Child BMI z scores and caregiver BMIs were correlated (r=0.16, P<0.0001). In multivariable models, children were 1.90 (95% confidence interval 1.31-2.74) times more likely to have BMI ≥95th percentile if their caregiver was obese. Five variables (fruits, unsweetened beverages, low-fat dairy, race, and caregiver's BMI) were significantly associated with child BMI z scores. Fruits were inversely related, whereas unsweetened beverages, low-fat dairy, and caregiver's BMI were positively associated with child BMI z score (P<0.03). Compared to whites, black and Hispanic children had lower BMI z scores (P<0.05).

CONCLUSIONS

The high prevalence of obesity in this population together with the observed inverse association between fruit consumption and BMI, if replicated in other studies, suggests that interventions that promote fruit consumption could have beneficial effects on child BMI.

Escherichia coli glycerol kinase: role of a tetramer interface in regulation by fructose 1,6-bisphosphate and phosphotransferase system regulatory protein IIIglc

Escherichia coli glycerol kinase (EC 2.7.1.30; ATP:glycerol 3-phosphotransferase) is a key element in a signal transduction pathway that couples expression of genes required for glycerol metabolism to the relative availability of glycerol and glucose. Its catalytic activity is inhibited by protein-protein interactions with IIIglc, a phosphotransferase system protein, and by fructose 1,6-bisphosphate (FBP); each of these allosteric effectors constitutes a positive signal that glucose is available. Loss of glucose inhibition of glycerol metabolism was used to screen for regulatory mutants of glycerol kinase after hydroxylamine mutagenesis of the cloned glpK gene. Two mutant enzymes were identified and shown by DNA sequencing to contain the mutations alanine 65 to threonine (A65T) and aspartate 72 to asparagine (D72N). Initial velocity studies show the mutations do not significantly affect the catalytic properties, hence active-site structures, of the enzymes. Both mutations decrease inhibition by FBP; A65T eliminates the inhibition while D72N appears to decrease the affinity for FBP and the extent of the inhibition. However, neither mutation significantly affects inhibition by IIIglc. Gel-permeation chromatography studies show that both of the mutations alter the dimer-tetramer assembly reaction of the enzyme and the effect of FBP in increasing the molecular weight. The effects of the mutations on the assembly reaction are consistent with the locations of these two amino acid residues in the X-ray structure, which shows them to be associated with an alpha-helix that constitutes one of the two subunit-subunit interfaces within the tetramer.(ABSTRACT TRUNCATED AT 250 WORDS)

Cation-promoted association of a regulatory and target protein is controlled by protein phosphorylation

A central question in molecular biology concerns the means by which a regulatory protein recognizes different targets. IIIGlc, the glucose-specific phosphocarrier protein of the bacterial phosphotransferase system, is also the central regulatory element of the PTS. Binding of unphosphorylated IIIGlc inhibits several non-PTS proteins, but there is little or no sequence similarity between IIIGlc binding sites on different target proteins. The crystal structure of Escherichia coli IIIGlc bound to one of its regulatory targets, glycerol kinase, has been refined at 2.6-A resolution in the presence of products, adenosine diphosphate and glycerol 3-phosphate. Structural and kinetic analyses show that the complex of IIIGlc with glycerol kinase creates an intermolecular Zn(II) binding site with ligation identical to that of the zinc peptidase thermolysin. The zinc is coordinated by the two active-site histidines of IIIGlc, a glutamate of glycerol kinase, and a water molecule. Zn(II) at 0.01 and 0.1 mM decreases the Ki of IIIGlc for glycerol kinase by factors of about 15 and 60, respectively. The phosphorylation of one of the histidines of IIIGlc, in its alternative role as phosphocarrier, provides an elegant means of controlling the cation-enhanced protein-protein regulatory interaction. The need for the target protein to supply only one metal ligand may account for the lack of sequence similarity among the regulatory targets of IIIGlc.

Crystallization and preliminary X-ray studies of human erythrocyte acylpeptide hydrolase

Crystals of acylpeptide hydrolase suitable for structure determination have been obtained. This enzyme removes the N-terminal formyl or acetyl group together with the first amino acid residue from N-terminal blocked peptides including bioactive peptides. One set of crystals, which diffract to 2.2 A, are in space group P2 with cell dimensions a = 118.6 A, b = 82.3 A, c = 182.1 A, beta = 91.6 degrees. The search for suitable heavy-atom derivatives is underway.