THU0054 NKTR-358, A NOVEL IL-2 CONJUGATE, STIMULATES HIGH LEVELS OF REGULATORY T CELLS IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS

Background:

Impaired IL-2 production and dysfunction of regulatory T cells (Tregs) have been identified as key immunological defects leading to the breakdown of immune self-tolerance in SLE. Low-dose IL-2 can expand Tregs, but the effect is limited by a narrow therapeutic window for Treg selectivity. Furthermore, the short half-life of IL-2 necessitates frequent administration. NKTR-358 is a polyethylene glycol (PEG) conjugate of recombinant human IL-2 (aldesleukin sequence) and is differentiated from native IL-2 by its altered binding to the IL-2 receptor and prolonged biological activity. NKTR-358 resulted in marked and selective stimulation of Tregs when administered as a single SC injection to healthy volunteers.

Objectives:

This multiple ascending dose study assessed the safety, tolerability, pharmacokinetics (PK), and immune effects of NKTR-358 in patients with SLE after repeated administration of SC doses. The time course and extent of changes in numbers and percentages of Tregs, conventional CD4+ and CD8+ T cells, NK cells, and cytokine levels in peripheral blood were investigated.

Methods:

In this double-blind, multiple ascending dose study, patients with mild to moderate SLE received 3 SC doses q2w in 4 cohorts ranging from 3.0 to 24.0 µg/kg (9 active:3 placebo per cohort); patients were followed for a total of 79 days.

Results:

There were no dose-limiting toxicities, deaths, or clinically significant abnormalities in either vital signs or electrocardiograms. Adverse events attributed to NKTR-358 were primarily limited to mild (grade 1) injection site reactions. At the highest dose, one subject had transient and mild (grade 1) symptoms of a flu-like syndrome after administration, without associated elevated cytokine levels, and another subject had dosing stopped due to elevated eosinophil levels. No other individual at any dose level had systemic signs or symptoms known to be associated with IL-2 therapy. No anti-drug antibodies were detected. NKTR-358 demonstrated dose-proportional PK with repeated dosing; plasma levels peaked 3-6 days post-dose and declined with a terminal half-life of ~10-13 days.

The primary and consistent effect of NKTR-358 was seen on Tregs. In the four dose cohorts, dose-dependent and sustained increases in absolute numbers and percentages of circulating CD4+FoxP3+CD25brightTregs were observed. Treg levels remained elevated throughout the dosing period, peaking at Day 10 after the first administration of NKTR-358 and returning to baseline ~ 20-30 days following last administration. At 24.0 µg/kg, the mean peak increase in numbers of CD25brightTregs was 11-fold above baseline. In addition, there was an increase in Treg activation markers at doses ≥12.0 µg/kg. In contrast to effects on Tregs, no changes in percentages or numbers of conventional CD4+ or CD8+ T cells were observed at any dose tested. At the highest dose, there were low-level increases in the percentages and numbers of NK cells. Overall, NKTR-358 selectively induced Tregs, evidenced by a 12-fold increase in the mean peak Treg:CD8 ratio over baseline in the 24.0 µg/kg group.

Conclusion:

NKTR-358, an IL-2 conjugate Treg stimulator, was well tolerated when repeatedly administered (q2w) at doses up to 24 µg/kg. Its administration led to marked, selective, prolonged, and dose-dependent increases in circulating CD25brightTregs. This clinical study in SLE patients extends the previous results in healthy volunteers and provides strong support for continued testing of NKTR-358 as a new therapeutic in SLE and other inflammatory diseases.

Disclosure of Interests:

Suresh Siddhanti Shareholder of: Nektar Therapeutics, Employee of: Nektar Therapeutics, Christie Fanton Shareholder of: Nektar Therapeutics, Employee of: Nektar Therapeutics, Neha Dixit Shareholder of: Nektar Therapeutics, Employee of: Nektar Therapeutics, Lin Lu Shareholder of: Nektar Therapeutics, Employee of: Nektar Therapeutics, Vishala Chindalore Grant/research support from: Nektar Therapeutics for conducted studies, Speakers bureau: > 5 years ago, Robert Levin Grant/research support from: Payments for clinical research for industry-sponsored trials, Consultant of: Gilead, Exagen, Myriad Rheumatology, Speakers bureau: Sanofi/Genzyme, Regeneron, Bristol-Myers Squibb, AbbVie, Isam Diab: None declared, Richard Furie Grant/research support from: Nektar Therapeutics to Northwell Rheumatology to conduct this study, Consultant of: Nektar Therapeutics, Jonathan Zalevsky Shareholder of: Nektar Therapeutics, Employee of: Nektar Therapeutics, Brian Kotzin Shareholder of: Nektar Therapeutics, Employee of: Nektar Therapeutics

Treatment data and technical process challenges for practical big data efforts in radiation oncology

The term Big Data has come to encompass a number of concepts and uses within medicine. This paper lays out the relevance and application of large collections of data in the radiation oncology community. We describe the potential importance and uses in clinical practice. The important concepts are then described and how they have been or could be implemented are discussed. Impediments to progress in the collection and use of sufficient quantities of data are also described. Finally, recommendations for how the community can move forward to achieve the potential of big data in radiation oncology are provided.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Thioredoxin fusion construct enables high-yield production of soluble, active matrix metalloproteinase-8 (MMP-8) in Escherichia coli

Matrix metalloproteinases (MMPs) are crucial proteases in maintaining the health and integrity of many tissues, however their dysregulation often facilitates disease progression. In disease states these remodeling and repair functions support, for example, metastasis of cancer by both loosening the matrix around tumors to enable cellular invasion and by affecting proliferation and apoptosis, and they promote degradation of biological restorations by weakening the substrate to which the restoration is attached. As such, MMPs are important therapeutic targets. MMP-8 participates in cancer, arthritis, asthma and failure of dental fillings. MMP-8 differs from other MMPs in that it has an insertion that enlarges its active site. To elucidate the unique features of MMP-8 and develop selective inhibitors to this therapeutic target, a stable and active form of the enzyme is needed. MMP-8 has been difficult to express at high yield in a soluble, active form. Typically recombinant MMPs accumulate in inclusion bodies and complex methods are applied to refold and purify protein in acceptable yield. Presented here is a streamlined approach to produce in Escherichia coli a soluble, active, stable MMP-8 fusion protein in high yield. This fusion shows much greater retention of activity when stored refrigerated without glycerol. A variant of this construct that contains the metal binding claMP Tag was also examined to demonstrate the ability to use this tag with a metalloprotein. SDS-PAGE, densitometry, mass spectrometry, circular dichroism spectroscopy and an activity assay were used to analyze the chemical integrity and function of the enzyme.

Future specialization interests among medical students in southern India

BACKGROUND

A consideration of the future specialization interests of undergraduate medical students might help to understand the needs of higher medical education and future manpower availability for healthcare.

METHODS

A cross-sectional study was conducted among 373 undergraduate students of a medical college in southern India using a self-administered questionnaire.

RESULTS

Of the 373 students, 188 (50.4%) were men. Almost all of them (370 [99.2%]) wanted to pursue postgraduation. Of these, 267 (72.4%) wanted to pursue postgraduation in India. Overall, the first choice subject was surgery (120 [32.2%]) followed by internal medicine (85 [22.8%]) and paediatrics (43 [11.5%]). The third preference for men and women differed, with men choosing orthopaedics and women choosing obstetrics and gynaecology. The factors that influenced the choice of specialization were interest in the speciality (Likert scale score 4.7), job satisfaction (4.6), employment opportunities (4.0), job security (4) and high income potential (3.9).

CONCLUSION

It was evident from the proportion of students desiring to do postgraduation and their choice of specialties that most of them will end up working at hospitals instead of at primary healthcare centres. The deficiencies of certain specialists such as ophthalmologists are likely to persist. This is a cause for concern as the majority of our population lives in rural areas and there is already a maldistribution of doctors.

Development and evaluation of a microemulsion formulation for transdermal delivery of terbinafine

The aim of the present study is to develop and evaluate microemulsion formulations for Terbinafine (TB) with a view to enhance its permeability through the skin and provide release for 24 h. Various o/w microemulsions were prepared by the spontaneous emulsification method. Oleic acid was chosen as the oil phase, Caprylo caproyl macrogol-8- glyceride (Labrasol S) and purified diethylene glycol monoethyl ether (Transcutol P) were used as surfactant and cosurfactant, respectively, on the basis of solubility studies. Pseudoternary phase diagrams were constructed to obtain the concentration range of oil, surfactant, cosurfactant, and water for microemulsion formulation. The optimized microemulsion consisted of 2% w/w TB, 8% w/w oleic acid, 31% w/w labrasol S, 31% w/w transcutol P, and 30% w/w distilled water. Permeability parameters like Jss and Kp were found to be significantly higher for formulation F4 as compared to other formulations (P < 0.05). Microbiological studies of TB in microemulsion showed better anti-fungal activity against Candida albicans and Aspergillus flavus as compared to marketed product (P < 0.05).

The role of ACE gene polymorphism in rapidity of progression of focal segmental glomerulosclerosis

BACKGROUND

The insertion/deletion (I/D) polymorphism of angiotensin converting enzyme (ACE) gene has been associated with progression of renal diseases.

AIMS

We investigated its role in the rate of progression of focal segmental glomerulosclerosis (FSGS).

METHODS

Forty-seven patients with end-stage renal disease (ESRD) due to FSGS were evaluated.

RESULTS

The distribution of ACE genotype was II-25.5%, ID-55.5%, and DD-19%, as compared to 40 controls with genotype of 7.5%, 60%, and 32.5%, respectively (p= NS). In African Americans (AA) the gene frequencies among patients and controls were I-43%, D-57% vs I-36%, D-64%, respectively. This was different than the gene frequencies in White/Hispanic (W/H) patients I-61.5%, D-38.5% vs I-38.6%, D-61.4%, in controls (P < 0.05). In 22 patients with rapid progression (RP) of FSGS to ESRD the genotype distribution was II-18%, ID -64%, and DD-18%. In 25 patients with FSGS who progressed slowly (SP) the genotype was similar (II-32%, ID-48% and DD-20%, P >0.05). With respect to rate of progression, D allele frequency was similar in AA patients (RP 64% vs SP 50%) and W/H patients (RP 36% vs SP 40%).

CONCLUSION

Our study reveals no association between the I/D polymorphism of the ACE gene and the presence of and rapidity progression of FSGS.

Genotyping of CYP21, linked chromosome 6p markers, and a sex-specific gene in neonatal screening for congenital adrenal hyperplasia

We investigated the feasibility and diagnostic utility of genotyping 9 CYP21 mutations, linked chromosome 6p markers, and a dimorphic X-Y marker from neonatal screening samples. Blood-impregnated filter papers (Guthrie cards) from 603 randomly chosen New Zealand neonates were genotyped blind to 17-hydroxyprogesterone (17-OHP) levels. Another 50 samples from Swiss and North American infants with correlative hormonal data were also genotyped. DNA was extracted, and gene-specific PCR was performed. CYP21 PCR products were subjected to ligase detection reaction, simultaneously analyzing 9 CYP21 mutations; PCR products of other genes were subjected to direct gel analysis. CYP21 genotyping indicated a heterozygote rate of 2.8% for classic mutations (excluding CYP21 deletions), and 2.0% for nonclassic mutations in New Zealanders. Ten full-term affected neonates showed a wide range of 17-OHP levels (15-1400 nmol/L). Sick or preterm infants or infants screened on the first day of life with high 17-OHP proved genetically unaffected. Genetic linkage disequilibrium was found between two CYP21 mutations and chromosome 6p markers. Guthrie cards can be used to accurately genotype CYP21 and other relevant markers, potentially enhancing the specificity and sensitivity of congenital adrenal hyperplasia screening. CYP21 heterozygote frequency for classic mutations is higher than expected based on genotype compared with that predicted by hormonal newborn screening.

Study of a kindred with classic congenital adrenal hyperplasia: diagnostic challenge due to phenotypic variance

We sought to determine the concordance of the phenotype and genotype in a kindred with classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency. The variation in phenotypic expression within this family underscores the difficulty of establishing the diagnosis in the absence of newborn screening, even with a heightened index of suspicion. Steroidogenic profiles were obtained for the three affected siblings. The available clinical history of the two affected aunts was retrieved. Genotyping was performed on several members of the kindred. Detailed sequencing of the entire CYP21 gene of two clinically dissimilar subjects in this family was undertaken to explore the possibility of other mutations or polymorphisms. PCR with ligase detection reaction analysis of CYP21 revealed that the affected family members III-2, III-3, III-4, II-3, and II-4, all were compound heterozygotes carrying the intron 2 point mutation known to interfere with splicing (nucleotide 656 A to G) and the exon 4 point mutation causing a nonconservative substitution of asparagine for isoleucine at codon 172 (I172N). Detailed sequencing of the gene was performed for the two most phenotypically dissimilar subjects. A single silent polymorphism was found in the third nucleotide for codon 248 in patient II-4, but not in patient III-4, and no additional mutations were found. Classic congenital adrenal hyperplasia remains a difficult diagnosis to make in the absence of newborn screening because of the variability of phenotypic expression. Likewise, the variable degree of genital ambiguity in affected females in this family serves to question universal advocacy of prenatal steroid treatment in pregnancies at risk for congenital adrenal hyperplasia. Extensive molecular exploration did not provide an explanation of the phenotypic heterogeneity and supports the possibility of influences other than the CYP21 gene for the observed divergence.

Steroid 21-hydroxylase expression and activity in human lymphocytes

Steroid 21-hydroxylase encoded by CYP21 is expressed in adrenal cortex. Mutations in CYP21 cause potentially lethal congenital adrenal hyperplasia (CAH). Earlier observations suggested alternative sources of 21-hydroxylase activity, although its genetic source remains unclear. We found a novel source of CYP21 expression in normal human cultured B lymphocytes. The quantity of 21-hydroxylase transcript was reduced in B cell lines of CAH subjects compared with that in normal B-lymphoblastoid cells. No CYP21 transcript was detected in lymphocytes from a CAH patient with homozygous CYP21 deletion. Cultured lymphoid cells, including those carrying homozygous CYP21 deletion, and peripheral blood leukocytes converted both 17-hydroxyprogesterone to 11-deoxycortisol and progesterone to deoxycorticosterone. We conclude that lymphocytes express CYP21, but also possess a 21-hydroxylase distinct from CYP21. Activity of this isozyme may partially compensate for severe adrenal 21-hydroxylase deficiency.