SAT0143 A PHASE 1 STUDY IN HEALTHY VOLUNTEERS EXPLORING THE SAFETY, PHARMACOKINETICS AND PHARMACODYNAMICS OF ATI-450: A NOVEL ORAL MK2 INHIBITOR

Background:

ATI-450, is an investigational small molecule inhibitor of the MAPK-activated protein kinase 2 (MK2) signaling pathway. This pathway drives the expression of multiple cytokines including TNFα, IL-1α and β, and IL-6.

Objectives:

We evaluated the safety and tolerability of ATI-450 in healthy volunteers as well as pharmacokinetics (PK) and pharmacodynamics (PD). Here we present data from single and multiple ascending dose cohorts. The aim was to select a dose for evaluation in phase 2 in patients with rheumatoid arthritis.

Methods:

Safety, PK and PD were assessed in a randomized, observer-blind, placebo-controlled, phase 1 study in male and female healthy subjects aged 18-55 (n=77).

Safety and tolerability of ATI-450 was evaluated based on adverse events, clinical laboratory, vital signs, 12-lead ECG, Holter monitoring, and physical examination. Blood was drawn for PK analysis at 0.5, 1, 2, 4, 6, 8, 12 hours, 24, 36, and 48 hours post dose in the SAD cohort and on day 7 of the MAD cohort. PD of ATI-450 were explored by investigating the inhibition of a target biomarker, phospho-HSP27 (pHSP27) and proinflammatory cytokines, TNFα, IL1β, IL6 and IL8 inex-vivoLPS-stimulated blood samples collected 4 and 12 hours post dose on day 7 from subjects in the MAD cohorts.

Results:

ATI-450 was generally well tolerated. No serious adverse events or severe adverse events were reported, and no adverse events led to discontinuation of the study medication. The most common adverse events (reported by 2 or more subjects who received ATI-450) observed during the trial were dizziness, headache, upper respiratory tract infection, constipation, nausea, and abdominal pain. All adverse events were mild. A trend of a decrease in absolute neutrophil count (ANC) was observed without correlated clinical sequelae.

ATI-450 had dose proportional PK with a terminal half-life (t½) of 9-12 hours in the MAD cohort on day 7. A dose and concentration dependent inhibition ofex vivostimulated cytokines and target biomarker was observed. On day 7, patients in the 50mg BID dose (the dose with the highest degree of inhibition) recorded mean trough drug levels (12 hours post dose) that were 1.4, 2.5, 2.5 and 2.4 times greater than the IC80for TNFα, IL1β, IL8 and pHSP27 respectively. Mean Cmax drug levels (4 hours post dose) were 3.6, 6.4, 6.2 and 6.0 times greater than the IC80for TNFα, IL1β, IL8 and pHSP27 respectively. IL6 levels were inhibited by more than 50% for part of the dosing interval.

Conclusion:

Oral ATI-450 was generally well tolerated at all doses with dose proportional PK. The t½ suggests that once or twice daily oral dosing may be possible. At the 50mg BID dose, marked inhibition of TNFα, IL1β and IL8, IL6 and pHSP27 was observed. ATI-450 has the potential to be an oral, small molecule drug which can target multiple cytokines. Exploration of its benefit to risk profile in patients with rheumatoid arthritis is warranted.

Disclosure of Interests:

Judy Schnyder Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, Joe Monahan Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, Walter Smith Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, Heidi Hope Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, Deborah Kelly Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, David Burt Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, E Huff Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, A Kaul Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, A Hildebrand Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, B Burnette Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, N Klug Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, M Bangs Shareholder of: Aclaris Therapeutics, Employee of: Aclaris Therapeutics, David Gordon Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics

Physicochemical characterisation of mangafodipir trisodium

Purpose: To determine the structure and various physicochemical properties of man-gafodipir (MnDPDP) trisodium, the active ingredient of Teslascan, a new organ-specific contrast medium for MR imaging.

Material and Methods: The structure of MnDPDP trisodium crystals was determined by X-ray crystallography. The possible existence of polymorphism in MnDPDP trisodium was evaluated by powder X-ray diffraction, optical microscopy, thermal analysis and IR spectroscopy. In addition, various spectroscopic techniques and physicochemical measurements were used for characterisation of MnDPDP trisodium.

Results: The crystallographic data obtained for MnDPDP trisodium show that the general core structure of the MnDPDP anion is similar to that seen in related substances. The metal coordination geometry is a distorted octahedron defined by 2 phenolate oxygens, 2 carboxylate oxygens and 2 amine nitrogens. The unit cell contains 2 MnDPDP anions, 6 sodium ions and 50 water molecules. The various spectroscopic data are consistent with the structure determined by X-ray crystallography. The product (Teslascan) has low viscosity, is isotonic with blood and has a physiological pH.

Conclusion: MnDPDP trisodium is a crystalline, hygroscopic solid which is readily soluble in water. No evidence of polymorphism was seen in the samples studied.

Clare wants the morning-after pill: what do practitioners think?

Focal points

Social domain dysfunction and disorganization in borderline personality disorder

BACKGROUND

Social dysfunction in personality disorder is commonly ascribed to abnormal temperamental traits but may also reflect deficits in social processing. In this study, we examined whether borderline and avoidant personality disorders (BPD, APD) may be differentiated by deficits in different social domains and whether disorganization of social domain functioning uniquely characterizes BPD.

METHOD

Patients were recruited from psychiatric clinics in Pittsburgh, USA, to provide a sample with BPD, APD and a no-personality disorder (no-PD) comparison group. Standardized assessments of Axis I and Axis II disorders and social domain dysfunction were conducted, including a new scale of 'domain disorganization' (DD).

RESULTS

Pervasive social dysfunction was associated with a 16-fold increase in the odds of an Axis II disorder. Both APD and BPD were associated with elevated social dysfunction. Romantic relationship dysfunction was associated specifically with BPD symptoms and diagnosis. DD was associated specifically with a categorical BPD diagnosis and with a dimensional BPD symptom count.

CONCLUSIONS

A focus on the inherently interpersonal properties of personality disorders suggests specific mechanisms (within and across interpersonal domains) that may help to account for the origins and maintenance of some disorders. In particular, BPD reflects disturbances in romantic relationships, consistent with a role for attachment processes, and in the organization of functioning across social domains.

Structure of bovine pancreatic trypsin inhibitor at 125 K definition of carboxyl-terminal residues Gly57 and Ala58

The structure of bovine pancreatic trypsin inhibitor has been refined to a resolution of 1.1 A against data collected at 125 K. The space group of the form II crystal is P2(1)2(1)2(1) with a = 75.39(3), b = 22.581(7), c = 28.606 (9) A (cf. a = 74.1, b = 23.4, c = 28.9 A at room temperature). The structure was refined by restrained least-squares minimization of summation operator w(F (o)(2)- F (c)(2))(2) with the SHELXL93 program. As the model improved, water molecules were included and exceptionally clear electron density was found for two residues, Gly57 and Ala58, that had been largely obscured at room temperature. The side chains of residues Glu7 and Arg53 were modelled over two positions with refined occupancy factors. The final model contains 145.6 water molecules distributed over 167 sites, and a single phosphate group disordered over two sites. The root-mean-square discrepancy between Calpha atoms in residues Arg1-Gly56 at room and low temperatures is 0.4 A. A comparison of models refined with anisotropic and isotropic thermal parameters revealed that there were no significant differences in atomic positions. The final weighted R-factor on F(2) (wR(2)) for data in the range 10-1.1 A was 35.9% for the anisotropic model and 40.9% for the isotropic model. Conventional R-factors based on F for F > 4sigma(F) were 12.2 and 14.6%, respectively, corresponding to 16.1 and 18.7% on all data. These large R-factor differences were not reflected in values of R(free), which were not significantly different at 21.5(5) and 21.8(4)%, respectively. These results, along with the relatively straightforward nature of the refinement, clearly highlight the benefits of low-temperature data collection.

Uric Acid Dihydrate Revisited

At 120 K, crystals of pure laboratory-grown uric acid dihydrate [7,9-dihydro-1H-purine-2,6,8(3H)-trione dihydrate], C5H4N4O3.2H2O, are monoclinic, P21/c, with a = 7.237 (3), b = 6.363 (4), c = 17.449 (11) Å, β = 90.51 (1)°, Z = 4, wR 2 (all data) = 0.1094, R 1 = 0.0406 for data with I > 2σ(I). The crystals exhibit pseudo-orthorhombic twinning with refined twin fractions of 0.89 and 0.11. Within each twin, disorder about a noncrystallographic twofold exists with refined occupancies of 0.83 and 0.17. Packing consists of layers of hydrogen-bonded uric acid separated by layers of hydrogen-bonded water. The epitaxy of uric acid dihydrate with its anhydrous counterpart is readily explicable from the refined model. Treatment of the structure as twinned and disordered in space group P21/c fully accounts for well documented violations of systematic absences in orthorhombic space groups.

Patients' perceptions of their physician's role in smoking cessation by age and readiness to stop smoking

BACKGROUND

Patients' perceptions of their physician's role in smoking cessation, using the 4As protocol (asking, advising, assisting, and arranging), were assessed with a focus on associations with age (18-29, 30-49, and > or = 50) and stage of readiness to stop smoking (precontemplation, contemplation, and preparation).

METHODS

Self-administered questionnaires were completed by 524 smokers presenting for regularly scheduled appointments at six clinics of an HMO in the Chicago metropolitan area.

RESULTS

Almost all patients said their physician should ask about their smoking status and advise them to quit. About half said their physician should assist them with quitting, and about two-thirds said their physician should follow up (arrange) on their smoking behavior. Bivariate associations were found for endorsement of the 4As with both age and stage. Multiple logistic regressions found age was the most consistent and strongest correlate of 4As endorsement, with younger smokers more likely than those age 50 or older to endorse the 4As protocol.

CONCLUSIONS

A proactive health promotion orientation should be encouraged among physicians. Patients should be screened for stage of readiness to stop smoking so that health-care providers can emphasize aspects of the 4As protocol that are most appropriate for each patient. Age-tailored smoking cessation strategies should be employed within stages of readiness to stop smoking.

Atomic Resolution Structure of Concanavalin A at 120 K

The structure of native concanavalin A has been refined to a resolution of 1.2 A against data collected at 120 K. The space group is I222, with a = 61.954 (8), b = 86.053 (11), c = 89.079 (11) A. The structure was refined by restrained weighted least-squares minimization of sum w(F(o)(2) - F(c)(2)(2) with SHELXL92/3/6. The final model contains all of the atoms from 237 amino acids, two metal ions and 271 water molecules spread over 287 sites. Disorder is modelled over two conformations for 30 amino-acid side chains. The final weighted R index on F(2) (wR(2)) on all data was 30.4%. Conventional R indices based on F were 14.2 and 11.8% for all data and for data with F > 4sigma(F), respectively.

Crystallization of the A alpha subunit of protein phosphatase 2A

The A alpha subunit of human protein phosphatase 2A forms crystals in space group P2(1) with cell dimensions a = 104.0, b = 174.9, c = 168.2 A, and beta angle = 90.2 degrees. At cryogenic temperatures, the crystals diffracted to a resolution limit of approximately 3.0 A. Based on the unit cell dimensions and a calculated molecular mass of 65,277 Da, the Matthews coefficient suggests eight molecules per asymmetric unit. Two native data sets were collected to a nominal resolution of 3.0 A and merged to provide a set that is 93% complete, with Rsym of 9.9%.

Comparison of crystal structure and theory for 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine

The crystal structure of the food mutagen 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP) has been determined by single-crystal X-ray crystallography. Crystals grown by evaporation of an aqueous solution form in the monoclinic space group P2(1)/n with two molecules of PhIP per asymmetric unit, along with six water molecules. The phenyl groups of these two PhIP molecules have torsion angles of different magnitude with respect to the plane of the imidazopyridine moiety. To maintain centrosymmetry, the crystal also contains an oppositely torsioned symmetry equivalent of each. The amino groups of both PhIP molecules take part in an extensive hydrogen bond network with the water of crystallization, forming long channels through the crystals parallel to the crystallographic b axis. The diffraction results are compared to theoretical calculations of the optimized geometry for a single PhIP molecule in vacuo as well as with water hydrogen-bonded to the exocyclic amine. In general, the agreement between the X-ray crystal structure of PhIP and its theory-derived counterpart in vacuo is within the combined experimental-theoretical uncertainty. The C-N bond to the exocyclic amine and the neighboring C=N imidazole bond are exceptions. This is attributed to the combined neglect of the crystal environment, waters of hydration, and the lack of coplanarity between the imidazole ring and the amine group in the calculations. To address the effect of waters of hydration, additional calculations were performed to optimize the geometry of a PhIP molecule with two water molecules hydrogen-bonded to the exocyclic amine. The resulting C-N exocyclic amine and C=N imidazole bond lengths were closer to those obtained by X-ray diffraction. The accord between theory and experiment demonstrates the utility of applying theory to (1) accurately predict structures of PhIP metabolites and intermediates that are too labile for study by conventional structural techniques such as X-ray crystallography and (2) assist in studying the mechanisms by which PhIP and its metabolites interact with proteins and DNA.

Aggregation of 2,3-dihydroxy-etiochlorin I. An amphiphilic model compound for photodynamic therapy and green heme d

The crystal structure of 2,3-dihydroxy-etiochlorin I has been determined to obtain information on its aggregation behavior. Cis-dihydroxychlorins serve as model compounds for green heme d and show promising photonecrotic activity in photodynamic therapy. The compound shows strong aggregation in the solid state facilitated by intramolecular hydrogen bonding between one hydroxy group and pyrrole nitrogens of neighboring molecules. This novel type of aggregation leads to chain-type aggregates in the crystal. The title compound 4 crystallized in the monoclinic space group Ia (Z = 4) with unit cell dimensions a = 9.902(4) A, b = 26.430(9) A, c = 10.823(5), beta = 104.47(3) A, V = 2743(2) A3. The structure was refined to an R-value of 0.097 on the basis of 1150 reflections with F > 4.0 sigma (F) (130 K).

The application of direct methods and Patterson interpretation to high-resolution native protein data

Conventional small-molecule methods of solving the phase problem from native data alone, without the use of heavy-atom derivatives, known fragment geometries or anomalous dispersion, have been tested on 0.9 A resolution data for two small proteins: rubredoxin, from Desulfovibrio vulgaris, and crambin. The presence of three disulfide bridges in crambin and an FeS(4) unit in rubredoxin enabled automated Patterson interpretation as well as direct methods to be tried. Although both structures were already well established, the known structures were not used in the phasing attempts, except for identifying successful solutions. Direct methods were not successful for crambin, although the correct phases were stable to phase refinement and gave figures of merit clearly superior to any obtained in the ca 500 000 random starting phase sets that were refined. It appears that the presence of an iron atom in rubredoxin reduces the scale of the search problem by many orders of magnitude, but at the cost of producing 'over-consistent' phase sets that overemphasize the iron atom and involve partial loss of enantiomorph information. However, about 1% of direct-methods trials were successful for rubredoxin, giving mean phase errors of about 56 degrees (for all E > 1.2) that could be reduced to about 20 degrees by standard E-Fourier recycling methods. Limiting the resolution of the data degraded the quality of the solutions and suggested that the limiting resolution for routine direct-methods solution of rubredoxin is about 1.2 A. With the 0.9 A data, automated Patterson interpretation convincingly finds the three disulfide bridges in crambin and the FeS(4) unit in rubredoxin, and in both cases E-Fourier recycling starting from these 'heavier' atoms yields almost the complete structure. Whereas crambin could only be solved in this way at very high resolution, rubredoxin could be solved by Patterson interpretation down to 1.6 A. These results emphasize the benefits of collecting protein data to the highest possible resolution, and indicate that when a few 'heavier' atoms are present, it may prove possible in favorable cases to solve the phase problem from a single native data set collected to 'atomic resolution'.

Three-dimensional structures of bulge-containing DNA fragments

The three-dimensional structure of a DNA tridecamer d(CGCAGAATTCGCG)2 containing bulged adenine bases was determined by single crystal X-ray diffraction methods, at 120 K, to 2.6 A resolution. The structure is a B-DNA type double helix with a single duplex in the asymmetric unit. One of the bulged adenine bases loops out from the double helix, while the other stacks in to it. This is in contrast to our preliminary finding, which indicated that both adenine bases were looped out. This revised model was confirmed by the use of a covalently bound heavy-atom derivative. The conformation of the looped-out bulge hardly disrupts base stacking interactions of the bases flanking it. This is achieved by the backbone making a "loop-the-loop" curve with the extra adenine flipping over with respect to the other nucleotides in the strand. The looped-out base intercalates into the stacked-in bulge site of a symmetrically related duplex. The looped-out and stacked-in bases form an A.A reversed Hoogsteen base-pair that stacks between the surrounding base-pairs, thus stabilizing both bulges. The double helix is frayed at one end with the two "melted" bases participating in intermolecular interactions. A related structure, of the same tridecamer, after soaking the crystals with proflavin, was determined to 3.2 A resolution. The main features of this B-DNA duplex are basically similar to the native tridecamer but differ in detail especially in the conformation of the bulged-out base. Accommodation of a large perturbation such as that described here with minimal disruption of the double helix shows both the flexibility and resiliency of the DNA molecule.

Cryocrystallography of ribosomal particles

Crystals suitable for X-ray study have been prepared from biochemically active ribosome particles or their complexes with tRNA and polypeptide chains. At ambient temperature the useful lifetime of these crystals under synchrotron irradiation is limited to a few minutes. However, upon cooling to cryogenic temperatures around 85 K, the original resolution limit (up to 4.5 A) can be recorded and radiation damage is virtually eliminated. Hence it has become possible to collect a complete data set from one single crystal. Crystals were cooled as rapidly as possible, either in a cold gas stream, or by immersion in liquid propane. Before cooling crystals were transferred either to an inert hydrocarbon environment, or to solutions similar to the crystallizing ones but with a higher viscosity. In several cases soaking in a cryosolvent was required. Crystallographic data were collected with intense synchrotron radiation. Full data sets have been measured for native and derivatized crystals of 50S ribosomal subunits from H. marismortui as well as from their complexes with tRNA and nascent polypeptide chains, from the wild type and a mutant of 50S subunits from B. stearothermophilus, and from crystals of native and derivatized 30S ribosomal subunits from T. thermophilus.

Low-temperature study of the A-DNA fragment d(GGGCGCCC)

The structure of the A-type duplex d(GGGCGCCC) was determined from data measured at 115 K to 2.0 A resolution. The space group, P4(3)2(1)2, is the same as for the 293 K structure; cell dimensions are a = 42.74 (4), c = 24.57 (1) A; R = 0.21 for 1694 observed reflections. The conformation and hydration are similar at the two temperatures. The average displacement parameters (B) for bases, sugars and phosphates all decrease by about 9 A2 relative to those found at 293 K. The individual values of B1/2 are linearly related to the distance from the molecular center of mass.

The three-dimensional structure of a DNA duplex containing looped-out bases

Unpaired bases in DNA have been assigned a possible role in the mechanism of frameshift mutagenesis in sequences with repeated base pairs. They also occur in quasipalindromic DNA sequences, which have been implicated in mutagenesis where there are no repeated base pairs, through the formation of single-stranded hairpin loops. The conformation of unpaired bases in DNA has been the subject of numerous thermodynamic as well as high resolution NMR (nuclear magnetic resonance) studies (reviewed in ref. 4). The NMR studies in solution have shown that the duplex of the tridecamer DNA fragment d(CGCAGAATTCGCG) remains intact, and that the unpaired adenosines are stacked into the duplex. Having crystallized this oligonucleotide and determined its structure, we find its conformation in the crystal is close to that of a B-DNA duplex, with the two additional adenosines looped out from the double helix and causing little disruption of the rest of the structure.

Cryocrystallography of biological macromolecules: a generally applicable method

Methods have been developed that allow facile X-ray data collection for biological macromolecules at cryogenic (near liquid N2) temperatures. The crystals are first transferred from their mother liquor to a hydrocarbon environment, then mounted with a standard glass fiber (no capillary), and flash cooled in situ with a cold nitrogen stream on the diffraction apparatus. This approach prevents freezing of the solvent in the crystals, so that they maintain their crystallographic integrity. Significant improvement of resolution can result from the cryogenic data collection, and radiation damage in the cooled crystals is greatly reduced, or eliminated, for the duration of data collection.

Stereochemical studies on medicinal agents. 25. Absolute configuration and analgetic potency of beta-1,2-dimethyl-2-phenyl-4-(propionyloxy)piperidine enantiomers

Enantiomers of beta-1,2-dimethyl-4-phenyl-4-(propionyloxy)piperidine (4) were employed as probes to demonstrate that opioid receptors are capable of distinguishing between the enantiotopic edges (the Ogston effect) of the piperidine ring. These enantiomers, (-)- and (+)-4.HCl, were prepared by esterification of the corresponding alcohols, (+)- and (-)-4a. Single crystal X-ray studies of (-)-4a.HCl reveal that it possesses the 2R,4S absolute configuration. Analgetic testing in mice (hot-plate) and receptor binding studies indicate that (-)-(2S,4R)-4.HCl is approximately ten times more potent than its enantiomer. The results are consistent with the operation of the Ogston effect in the interaction of achiral 4-phenylpiperidines with opioid receptors. Additionally, it is suggested that the piperidine ring of these and other closely related 4-phenylpiperidines bind within a receptor subsite cleft whose dimensions exclude diequatorial 2,6- and 3,5-dimethyl-substituted ligands.