KRAS is vulnerable to reversible switch-II pocket engagement in cells.

Current small-molecule inhibitors of KRAS(G12C) bind irreversibly in the switch-II pocket (SII-P), exploiting the strong nucleophilicity of the acquired cysteine as well as the preponderance of the GDP-bound form of this mutant. Nevertheless, many oncogenic KRAS mutants lack these two features, and it remains unknown whether targeting the SII-P is a practical therapeutic approach for KRAS mutants beyond G12C. Here we use NMR spectroscopy and a cellular KRAS engagement assay to address this question by examining a collection of SII-P ligands from the literature and from our own laboratory. We show that the SII-Ps of many KRAS hotspot (G12, G13, Q61) mutants are accessible using noncovalent ligands, and that this accessibility is not necessarily coupled to the GDP state of KRAS. The results we describe here emphasize the SII-P as a privileged drug-binding site on KRAS and unveil new therapeutic opportunities in RAS-driven cancer.

Long-term efficacy of certolizumab pegol for the treatment of plaque psoriasis: 3-year results from two randomized phase III trials (CIMPASI-1 and CIMPASI-2).

BACKGROUND: Certolizumab pegol (CZP) is an Fc-free, PEGylated anti-tumour necrosis factor biologic. OBJECTIVES: To report the 3-year efficacy of CZP in plaque psoriasis, pooled from the CIMPASI-1 (NCT02326298) and CIMPASI-2 (NCT02326272) phase III trials. METHODS: Adults with moderate-to-severe psoriasis for ≥ 6 months were randomized 2 : 2 : 1 to CZP 200 mg, CZP 400 mg or placebo, every 2 weeks (Q2W) for up to 48 weeks. Patients entering the open-label period (weeks 48-144) from double-blinded CZP initially received CZP 200 mg Q2W. Patients not achieving ≥ 50% improvement in Psoriasis Area and Severity Index (PASI 50) at week 16 entered an open-label CZP 400 mg Q2W escape arm (weeks 16-144). Dose adjustments based on PASI response were permitted during open-label treatment. Outcomes included PASI 75, PASI 90 and Physician's Global Assessment (PGA) 0/1 responder rates, based on a logistic regression model (missing data imputed using Markov Chain Monte Carlo methodology). RESULTS: In total, 186 patients were randomized to CZP 200 mg Q2W and 175 to CZP 400 mg Q2W. At week 48, PASI 75/90 was achieved by 72·7%/51·3% of patients randomized to CZP 200 mg and 84·4%/62·7% randomized to CZP 400 mg. Patients entering the open-label period at week 48, from blinded treatment, received CZP 200 mg Q2W. At week 144, PASI 75/90 was achieved by 70·6%/48·7% patients randomized to CZP 200 mg and 72·9%/42·7% randomized to CZP 400 mg. At week 16, 72 placebo-randomized patients entered the CZP 400 mg Q2W escape arm; 75.7%/58.5% achieved PASI 75/90 at week 144. CONCLUSIONS: Both CZP 200 mg and 400 mg Q2W demonstrated sustained, durable efficacy, with numerically higher responses for some outcomes with 400 mg Q2W.

Long-term safety of certolizumab pegol in plaque psoriasis: pooled analysis over 3 years from three phase III, randomized, placebo-controlled studies.

BACKGROUND: Certolizumab pegol (CZP) is an Fc-free, PEGylated anti-tumour necrosis factor biologic. OBJECTIVES: To report 3-year safety data from three phase III trials of CZP in adults with plaque psoriasis. METHODS: Data were pooled from CIMPASI-1 (NCT02326298), CIMPASI-2 (NCT02326272) and CIMPACT (NCT02346240). Included patients had moderate-to-severe plaque psoriasis of ≥ 6 months' duration; had been randomized to CZP 200 mg every 2 weeks (Q2W) (400 mg at weeks 0, 2 and 4) or CZP 400 mg Q2W; and had received at least one dose of CZP with up to 144 weeks of exposure. Treatment-emergent adverse events (TEAEs) were classified using MedDRA v18·1. Reported incidence rates (IRs) are incidence of new cases per 100 patient-years (PY). RESULTS: Over 144 weeks, 995 patients received at least one dose of CZP (exposure: 2231·3 PY); 731 and 728 received at least one dose of CZP 200 mg Q2W (1211·4 PY) and/or 400 mg Q2W (1019·9 PY), respectively. The IR [95% confidence interval (CI)] of TEAEs was 144·9 (135·3-155·0) for all patients, 134·1 (123·2-145·7) for CZP 200 mg Q2W and 158·3 (145·5-171·9) for CZP 400 mg Q2W. The IR (95% CI) of serious TEAEs for all patients was 7·5 (6·4-8·8); the IRs were 6·7 (5·2-8·3) and 8·7 (6·9-10·8) for CZP 200 mg and 400 mg Q2W, respectively. Overall, 3·2% of patients reported serious infections (2·2% within each of the CZP 200 and 400 mg Q2W groups). Overall, there was one case of active tuberculosis, 16 malignancies in 14 patients and seven deaths (two considered treatment-related). The cumulative IR of TEAEs did not increase over time. CONCLUSIONS: No new safety signals were identified compared with previously reported data. Risk did not increase with longer or higher CZP exposure.

Three-year efficacy and safety of certolizumab pegol for the treatment of plaque psoriasis: results from the randomized phase 3 CIMPACT trial.

BACKGROUND: Certolizumab pegol (CZP) is an Fc-free, PEGylated anti-tumor necrosis factor biologic. OBJECTIVES: To report 3-year outcomes from the CIMPACT (NCT02346240) phase 3, CZP in moderate to severe plaque psoriasis, randomized controlled trial. METHODS: Adults were randomized 3:3:3:1 to CZP 200 mg every other week (Q2W), CZP 400 mg Q2W, etanercept biweekly or placebo. At Week 16, CZP- and etanercept-treated PASI 75 responders were re-randomized to CZP 200 mg Q2W, CZP 400 mg Q4W, CZP 400 mg Q2W or placebo for maintenance treatment; PASI 75 non-responders entered an open-label escape CZP 400 mg Q2W arm. Patients entering the open-label extension (OLE; Weeks 48-144) from blinded treatment received CZP 200 mg Q2W. RESULTS: Double-blinded results have been reported previously. 261 patients received 200 mg Q2W upon OLE entry. PASI 75 response was maintained in patients continuing 200 mg Q2W treatment through Weeks 16-144 (Week 144: 96.2%). In patients dosed down at Week 48 (double-blinded 400 mg to 200 mg Q2W), PASI 75 decreased (Week 48: 98.7%; Week 144: 85.9%). In patients who received placebo through Weeks 16-48, PASI 75 response decreased (Week 48: 60.4%), then increased following Week 48 switch to 200 mg Q2W (Week 144: 95.1%). 48 and 36 patients initially randomized to 200 and 400 mg Q2W, respectively, were Week 16 PASI 75 non-responders and entered the escape arm; at Week 144, 71.8% and 78.2% achieved PASI 75. No new safety signals were identified. CONCLUSIONS: Response to CZP was durable over three years; no new safety signals were identified.

The ballistic performance of bone when impacted by fragments.

Physical models are required to generate the underlying algorithms that populate computer simulations of the effects of explosive fragmenting devices. These models and simulations are used for understanding weapon performance, designing buildings and optimising personal protective equipment. Previous experimental work has investigated the performance of skin and muscle when subjected to fragmentation threats, but limited evidence exists for the performance of bone when impacted by fragments. In the current work, ballistic testing was conducted using two types of internationally recognised steel fragment simulating projectiles (FSPs): (i) 5.5 mm diameter (0.68 g) ball bearing (BBs) and (ii) 1.10 g chisel nosed (CN). These projectiles were fired at isolated swine ribs at impact velocities between 99 and 1265 m/s. Impact events were recorded using a high-speed camera. Selected specimens were analysed post-impact with plain x-radiographs and micro-CT scanning to determine damage to the bone architecture. Bones were perforated with a kinetic energy density (KED) as low as 0.14 J/mm2. Energy transfer to the bone was greater for the CN FSPs, resulting in increased bone damage and the production of secondary bone fragments. The manner in which the bones failed with faster velocity impacts (> 551 m/s; KED > 6.44 J/mm2) was analogous to the behaviour of a brittle material. Slower velocity impacts (< 323 m/s; KED < 1.49 J/mm2) showed a transition in failure mode with the bone displaying the properties of an elastic, plastic and brittle material at various points during the impact. The study gives critical insight into how bone behaves under these circumstances.

Detection of Experimental and Clinical Immune Complexes by Measuring SHIP-1 Recruitment to the Inhibitory FcγRIIB.

Fc γ receptors (FcγR) are involved in multiple aspects of immune cell regulation, are central to the success of mAb therapeutics, and underpin the pathology of several autoimmune diseases. However, reliable assays capable of accurately measuring FcγR interactions with their physiological ligands, IgG immune complexes (IC), are limited. A method to study and detect IC interactions with FcγRs was therefore developed. This method, designed to model the signaling pathway of the inhibitory FcγRIIB (CD32B), used NanoLuc Binary Interaction Technology to measure recruitment of the Src homology 2 domain-containing inositol phosphatase 1 to the ITIM of this receptor. Such recruitment required prior cross-linking of an ITAM-containing activatory receptor, and evoked luciferase activity in discrete clusters at the cell surface, recapitulating the known biology of CD32B signaling. The assay detected varying forms of experimental IC, including heat-aggregated IgG, rituximab-anti-idiotype complexes, and anti-trinitrophenol-trinitrophenol complexes in a sensitive manner (≤1 µg/ml), and discriminated between complexes of varying size and isotype. Proof-of-concept for the detection of circulating ICs in autoimmune disease was provided, as responses to sera from patients with systemic lupus erythematosus and rheumatoid arthritis were detected in small pilot studies. Finally, the method was translated to a stable cell line system. In conclusion, a rapid and robust method for the detection of IC was developed, which has numerous potential applications including the monitoring of IC in autoimmune diseases and the study of underlying FcγR biology.

Preliminary study into the skeletal injuries sustained to the spine from posterior non-perforating ballistic impacts into body armour.

INTRODUCTION: The aim of this paper was to examine any injuries from posterior behind armour blunt trauma ballistic impacts directly over the spine onto typical hard body armours. Due to the spine being close to the surface of the skin and a lack of any previous specific research into this topic, this study was designed to gain preliminary insight into the mechanisms involved and injuries caused. Pigs were chosen as the closest representative of human spine, tissue and skin, although their spines are deeper under the surface than humans. Baseline spine and ribs shots were conducted to ensure that the study was effective. METHOD: This study used a 65 kg cadaveric pig eviscerated torso and 7.62 NATO ammunition (7.62×51; L2A2; mean velocity=838 m/s, SD=4 m/s) impacting hard body armour plates over the spine. Injuries were inspected, and sections were removed for X-ray and micro-CT assessment. RESULTS: There was no visible soft tissue damage under the impact point on the armour over the spine, and no bony injuries were reported. Baseline rib shots resulted in multiple rib fractures; some showed minimal displacement of the bone. Baseline spine shot resulted in damage across the spine involving spinal cord and bone. CONCLUSION: No injuries were noted from the spinal impacts, and the rib shots resulted in injuries consistent with those previously reported. The anatomical differences between pigs and humans does not preclude that bony injuries could occur in a human from these types of spinal ballistic impacts.

Live cell evaluation of granzyme delivery and death receptor signaling in tumor cells targeted by human natural killer cells.

Growing interest in natural killer (NK) cell-based therapy for treating human cancer has made it imperative to develop new tools to measure early events in cell death. We recently demonstrated that protease-cleavable luciferase biosensors detect granzyme B and pro-apoptotic caspase activation within minutes of target cell recognition by murine cytotoxic lymphocytes. Here we report successful adaptation of the biosensor technology to assess perforin-dependent and -independent induction of death pathways in tumor cells recognized by human NK cell lines and primary cells. Cell-cell signaling via both Fc receptors and NK-activating receptors led to measurable luciferase signal within 15 minutes. In addition to the previously described aspartase-cleavable biosensors, we report development of granzyme A and granzyme K biosensors, for which no other functional reporters are available. The strength of signaling for granzyme biosensors was dependent on perforin expression in IL-2-activated NK effectors. Perforin-independent induction of apoptotic caspases was mediated by death receptor ligation and was detectable after 45 minutes of conjugation. Evidence of both FasL and TRAIL-mediated signaling was seen after engagement of Jurkat cells by perforin-deficient human cytotoxic lymphocytes. Although K562 cells have been reported to be insensitive to TRAIL, robust activation of pro-apoptotic caspases by NK cell-derived TRAIL was detectable in K562 cells. These studies highlight the sensitivity of protease-cleaved luciferase biosensors to measure previously undetectable events in live cells in real time. Further development of caspase and granzyme biosensors will allow interrogation of additional features of granzyme activity in live cells including localization, timing, and specificity.

Three Efficient Methods for Preparation of Coelenterazine Analogues.

The growing popularity of bioluminescent assays has highlighted the need for coelenterazine analogues possessing properties tuned for specific applications. However, the structural diversity of known coelenterazine analogues has been limited by current syntheses. Known routes for the preparation of coelenterazine analogues employ harsh reaction conditions that limit access to many substituents and functional groups. Novel synthetic routes reported here establish simple and robust methods for synthesis and investigation of structurally diverse marine luciferase substrates. Specifically, these new routes allow synthesis of coelenterazine analogues containing various heterocyclic motifs and substituted aromatic groups with diverse electronic substituents at the R(2) position. Interesting analogues described herein were characterized by their physicochemical properties, bioluminescent half-life, light output, polarity and cytotoxicity. Some of the analogues represent leads that can be utilized in the development of improved bioluminescent systems.

Real-time detection of CTL function reveals distinct patterns of caspase activation mediated by Fas versus granzyme B.

Activation of caspase-mediated apoptosis is reported to be a hallmark of both granzyme B- and Fas-mediated pathways of killing by CTLs; however, the kinetics of caspase activation remain undefined owing to an inability to monitor target cell-specific apoptosis in real time. We have overcome this limitation by developing a novel biosensor assay that detects continuous, protease-specific activity in target cells. Biosensors were engineered from a circularly permuted luciferase, linked internally by either caspase 3/7 or granzyme B/caspase 8 cleavage sites, thus allowing activation upon proteolytic cleavage by the respective proteases. Coincubation of murine CTLs with target cells expressing either type of biosensor led to a robust luminescent signal within minutes of cell contact. The signal was modulated by the strength of TCR signaling, the ratio of CTL/target cells, and the type of biosensor used. Additionally, the luciferase signal at 30 min correlated with target cell death, as measured by a (51)Cr-release assay. The rate of caspase 3/7 biosensor activation was unexpectedly rapid following granzyme B- compared with Fas-mediated signal induction in murine CTLs; the latter appeared gradually after a 90-min delay in perforin- or granzyme B-deficient CTLs. Remarkably, the Fas-dependent, caspase 3/7 biosensor signal induced by perforin-deficient human CTLs was also detectable after a 90-min delay when measured by redirected killing. Thus, we have used a novel, real-time assay to demonstrate the distinct pattern of caspase activation induced by granzyme B versus Fas in human and murine CTLs.

A luminescent assay for real-time measurements of receptor endocytosis in living cells.

Ligand-mediated endocytosis is a key autoregulatory mechanism governing the duration and intensity of signals emanating from cell surface receptors. Due to the mechanistic complexity of endocytosis and its emerging relevance in disease, simple methods capable of tracking this dynamic process in cells have become increasingly desirable. We have developed a bioluminescent reporter technology for real-time analysis of ligand-mediated receptor endocytosis using genetic fusions of NanoLuc luciferase with various G-protein-coupled receptors (GPCRs). This method is compatible with standard microplate formats, which should decrease work flows for high-throughput screens. This article also describes the application of this technology to endocytosis of epidermal growth factor receptor (EGFR), demonstrating potential applicability of the method beyond GPCRs.

Pattern of response in patients with moderate-to-severe psoriasis treated with etanercept.

BACKGROUND: Etanercept (ETN) 50 mg once weekly (QW) or 50 mg twice weekly (BIW) for 12 weeks, followed by 50 mg QW in all subjects to Week 24 improved psoriasis in patients with concomitant psoriatic arthritis in the PRESTA trial. OBJECTIVES: To use data from PRESTA to evaluate the effect of ETN in the treatment of psoriasis by Psoriasis Area Severity Index (PASI) body-region and component, and determine if PASI responses correlate with the Dermatology Life Quality Index (DLQI). METHODS: Median time to 75% improvement in PASI (PASI75), body- and component-specific subscales over 24 weeks were estimated. Pearson correlation coefficients determined the association between DLQI score and PASI total score, body- and component-specific subscales with ETN treatment at baseline and up to Week 24. RESULTS: In total, 748 patients from PRESTA were included (ETN 50 mg QW/QW, n = 371; BIW/QW, n = 377). Patients achieved PASI75 total score and 75% improvements in all body regions and components faster on ETN 50 mg BIW/QW than QW/QW (all P < 0·05). Median time to 75% improvement was faster for the head and trunk followed by upper and lower extremities, and for induration and desquamation followed by erythema and total area. Weak to moderately positive correlations between improvements in DLQI and PASI total score (r = 0·223-0·463), all PASI body-specific (r = 0·114-0·432) and component-specific (r = 0·178-0·478) subscales were observed over 24 weeks. CONCLUSIONS: Etanercept treatment-response appears to occur in a body- and component-specific manner. Changes in quality of life are not captured by PASI or its subscales.

Lenalidomide and high-dose dexamethasone compared with dexamethasone as initial therapy for multiple myeloma: a randomized Southwest Oncology Group trial (S0232).

The Southwest Oncology Group conducted a randomized trial comparing lenalidomide (LEN) plus dexamethasone (DEX; n = 97) to placebo (PLC) plus DEX (n = 95) in newly diagnosed myeloma. Three 35-day induction cycles applied DEX 40 mg/day on days 1 to 4, 9 to 12, and 17 to 20 together with LEN 25 mg/day for 28 days or PLC. Monthly maintenance used DEX 40 mg/day on days 1 to 4 and 15 to 18 along with LEN 25 mg/day for 21 days or PLC. Crossover from PLC-DEX to LEN-DEX was encouraged on progression. One-year progression-free survival, overall response rate, and very good partial response rate were superior with LEN-DEX (78% vs 52%, P = .002; 78% vs 48%, P < .001; 63% vs 16%, P < .001), whereas 1-year overall survival was similar (94% vs 88%; P = .25). Toxicities were more pronounced with LEN-DEX (neutropenia grade 3 or 4: 21% vs 5%, P < .001; thromboembolic events despite aspirin prophylaxis: 23.5% [initial LEN-DEX or crossover] vs 5%; P < .001). This trial was registered at www.clinicaltrials.gov as #NCT00064038.

Development of a cell-free split-luciferase biochemical assay as a tool for screening for inhibitors of challenging protein-protein interaction targets.

Targeting the interaction of proteins with weak binding affinities or low solubility represents a particular challenge for drug screening. The NanoLuc â ® Binary Technology (NanoBiT â ®) was originally developed to detect protein-protein interactions in live mammalian cells. Here we report the successful translation of the NanoBit cellular assay into a biochemical, cell-free format using mammalian cell lysates. We show that the assay is suitable for the detection of both strong and weak protein interactions such as those involving the binding of RAS oncoproteins to either RAF or phosphoinositide 3-kinase (PI3K) effectors respectively, and that it is also effective for the study of poorly soluble protein domains such as the RAS binding domain of PI3K. Furthermore, the RAS interaction assay is sensitive and responds to both strong and weak RAS inhibitors. Our data show that the assay is robust, reproducible, cost-effective, and can be adapted for small and large-scale screening approaches. The NanoBit Biochemical Assay offers an attractive tool for drug screening against challenging protein-protein interaction targets, including the interaction of RAS with PI3K.

Ligand-regulated peptide aptamers that inhibit the 5'-AMP-activated protein kinase.

In an effort to extend the peptide aptamer approach, we have developed a scaffold protein that allows small molecule ligand control over the presentation of a peptide aptamer. This scaffold, a fusion of three protein domains, FKBP12, FRB, and GST, presents a peptide linker region for target protein binding only in the absence of the small molecule Rapamycin or other non-immunosuppressive Rapamycin derivatives. Here we describe the characterization of ligand-regulated peptide aptamers that interact with and inhibit the 5'-AMP-activated protein kinase (AMPK). AMPK, a central regulator of cellular energy homeostasis, responds to high cellular AMP/ATP ratios by promoting energy producing pathways and inhibiting energy consuming biosynthetic pathways. We have characterized 15 LiRPs of similar, poly-basic sequence and have determined that they interact with the substrate peptide binding region of both AMPK alpha1 and alpha2. These proteins, some of which serve as poor substrates of AMPK, inhibit the kinase as pseudosubstrates in a Rapamycin-regulated fashion in vitro, an effect that is largely competitive with substrate peptide and mediated by an increase in the kinase's apparent K(m) for substrate peptide. This pseudosubstrate inhibition of AMPK by LiRP proteins reduced the AMP stimulation of AMPK in vitro and caused the inhibited state of the kinase to kinetically resemble the basal, unstimulated state of AMPK, providing potential insight into the molecular mechanisms of AMP stimulation of AMPK.

CRISPR-Mediated Tagging of Endogenous Proteins with a Luminescent Peptide.

Intracellular signaling pathways are mediated by changes in protein abundance and post-translational modifications. A common approach for investigating signaling mechanisms and the effects induced by synthetic compounds is through overexpression of recombinant reporter genes. Genome editing with CRISPR/Cas9 offers a means to better preserve native biology by appending reporters directly onto the endogenous genes. An optimal reporter for this purpose would be small to negligibly influence intracellular processes, be readily linked to the endogenous genes with minimal experimental effort, and be sensitive enough to detect low expressing proteins. HiBiT is a 1.3 kDa peptide (11 amino acids) capable of producing bright and quantitative luminescence through high affinity complementation (KD = 700 pM) with an 18 kDa subunit derived from NanoLuc (LgBiT). Using CRISPR/Cas9, we demonstrate that HiBiT can be rapidly and efficiently integrated into the genome to serve as a reporter tag for endogenous proteins. Without requiring clonal isolation of the edited cells, we were able to quantify changes in abundance of the hypoxia inducible factor 1A (HIF1α) and several of its downstream transcriptional targets in response to various stimuli. In combination with fluorescent antibodies, we further used HiBiT to directly correlate HIF1α levels with the hydroxyproline modification that mediates its degradation. These results demonstrate the ability to efficiently tag endogenous proteins with a small luminescent peptide, allowing sensitive quantitation of the response dynamics in their regulated expression and covalent modifications.

Correcting errors in synthetic DNA through consensus shuffling.

Although efficient methods exist to assemble synthetic oligonucleotides into genes and genomes, these suffer from the presence of 1-3 random errors/kb of DNA. Here, we introduce a new method termed consensus shuffling and demonstrate its use to significantly reduce random errors in synthetic DNA. In this method, errors are revealed as mismatches by re-hybridization of the population. The DNA is fragmented, and mismatched fragments are removed upon binding to an immobilized mismatch binding protein (MutS). PCR assembly of the remaining fragments yields a new population of full-length sequences enriched for the consensus sequence of the input population. We show that two iterations of consensus shuffling improved a population of synthetic green fluorescent protein (GFPuv) clones from approximately 60 to >90% fluorescent, and decreased errors 3.5- to 4.3-fold to final values of approximately 1 error per 3500 bp. In addition, two iterations of consensus shuffling corrected a population of GFPuv clones where all members were non-functional, to a population where 82% of clones were fluorescent. Consensus shuffling should facilitate the rapid and accurate synthesis of long DNA sequences.

Spatial photorelease of oligonucleotides, using a safety-catch photolabile linker.

[reaction: see text] We report the development of a safety-catch photolabile linker that allows the light-directed synthesis and spatially selective photorelease of oligonucleotides from microarrays. The linker remains stable to light during DNA synthesis, and is activated for photorelease after acidic hydrolysis. We demonstrate that the photoreleased oligonucleotides can be amplified by PCR to produce double stranded DNA. The advantages offered by this linker could aid the development of an automated gene synthesis platform.

Ligand-regulated peptides: a general approach for modulating protein-peptide interactions with small molecules.

We engineered a novel ligand-regulated peptide (LiRP) system where the binding activity of intracellular peptides is controlled by a cell-permeable small molecule. In the absence of ligand, peptides expressed as fusions in an FKBP-peptide-FRB-GST LiRP scaffold protein are free to interact with target proteins. In the presence of the ligand rapamycin, or the nonimmunosuppressive rapamycin derivative AP23102, the scaffold protein undergoes a conformational change that prevents the interaction of the peptide with the target protein. The modular design of the scaffold enables the creation of LiRPs through rational design or selection from combinatorial peptide libraries. Using these methods, we identified LiRPs that interact with three independent targets: retinoblastoma protein, c-Src, and the AMP-activated protein kinase. The LiRP system should provide a general method to temporally and spatially regulate protein function in cells and organisms.

Efficacy of etanercept in combination with methotrexate in moderate-to-severe rheumatoid arthritis is not dependent on methotrexate dosage.

OBJECTIVE: To evaluate the impact of methotrexate (MTX) dosage on clinical, functional and quality of life outcomes in patients with rheumatoid arthritis (RA) from two previous etanercept (ETN) trials after 24 months of treatment. METHODS: Patients with active RA in the ETN+MTX combination treatment arms of the Trial of Etanercept and Methotrexate with Radiographic Patient Outcomes (TEMPO) and COmbination of Methotrexate and ETanercept in Active Early Rheumatoid Arthritis (COMET) studies were pooled in this post hoc analysis and stratified by MTX dosage at 24 months, having MTX monotherapy groups as control: low dose, <10.0 mg/week; medium dose, 10.0-17.5 mg/week; and high dose, >17.5 mg/week. Data from these patient subgroups were included in descriptive summaries of demographic and disease characteristics at baseline. The following outcomes at 24 months were also evaluated for each subgroup: Disease Activity Score in 28 joints (DAS28) low disease activity (LDA) and remission; American College of Rheumatology 20%, 50% and 70% improvement criteria (ACR20, 50 and 70) responses; and changes from baseline in DAS28, Health Assessment Questionnaire Disease Index (HAQ-DI) and EuroQol 5-dimensions visual analogue scale (EQ-5D VAS). RESULTS: Baseline demographics were similar between the low, medium and high MTX dose groups in the ETN+MTX combination and MTX monotherapy arms, with the exception of disease duration (ETN+MTX low 5.5; medium 5.1; high 0.8 years vs MTX low 8.3; medium 4.7; high 0.8 years). Responses to ETN+MTX combination therapy at 24 months were consistently high across MTX dosage groups, with very similar rates of DAS28 LDA/remission and ACR20/50/70. Improvements in DAS28, HAQ-DI and EQ-5D VAS were also not dependent on MTX dosage in the combination treatment arm. CONCLUSIONS: Patients with RA in the TEMPO and COMET trials who received ETN+MTX showed similar efficacy outcomes at 24 months, regardless of MTX dosage. TRIAL REGISTRATION NUMBERS: NCT00195494 (COMET) and NCT00393471 (TEMPO).