Comparative effectiveness of preventive treatment with dimethyl fumarate-loaded solid lipid nanoparticles and oral dimethyl fumarate in a mouse model of multiple sclerosis.

BACKGROUND: Orally administered dimethyl fumarate (DMF) presents gastrointestinal adverse effects, such as pain and diarrhea, in addition to flushing and lymphopenia. OBJECTIVE: Solid lipid nanoparticles (SLNs) with DMF were developed for subcutaneous administration. METHODS: DMF-incorporated SLNs and free DMF were tested in mice induced with experimental autoimmune encephalomyelitis (EAE). RESULTS: Preventive treatment of free or incorporated DMF were able to reduce the EAE clinical scores, increase the weight of the animals, reduce the lesion area (demyelination and infiltration), reduce microglial fluorescence intensity and reduce the number of microglial cells and astrocytes, when compared to untreated EAE animals. Groups that received DMF had reduced numbers of T cells, B cells and natural killer (NK) cells in the blood, when compared to the non-induced group. CONCLUSIONS: DMF incorporated in SLNs was as effective as free DMF in reducing the clinical scores of the animals, but with reduced administrations when given subcutaneously. In addition, SLN-DMF preventive treatment partially prevented a reduction in the percentages of T and B cells, in the blood, when compared to preventive treatment with free DMF (oral), which suggests reduction of lymphopenia.

Development of an In Vitro System To Emulate an In Vivo Subcutaneous Environment: Small Molecule Drug Assessment.

A reliable in vitro system can support and guide the development of subcutaneous (SC) drug products. Although several in vitro systems have been developed, they have some limitations, which may hinder them from getting more engaged in SC drug product development. This study sought to develop a novel in vitro system, namely, Emulator of SubCutaneous Absorption and Release (ESCAR), to better emulate the in vivo SC environment and predict the fate of drugs in SC delivery. ESCAR was designed using computer-aided design (CAD) software and fabricated using the three-dimensional (3D) printing technique. ESCAR has a design of two acceptor chambers representing the blood uptake pathway and the lymphatic uptake pathway, respectively, although only the blood uptake pathway was investigated for small molecules in this study. Via conducting a DoE factor screening study using acetaminophen solution, the relationship of the output (drug release from the "SC" chamber to the "blood circulation" chamber) and the input parameters could be modeled using a variety of methods, including polynomial equations, machine learning methods, and Monte Carlo simulation-based methods. The results suggested that the hyaluronic acid (HA) concentration was a critical parameter, whereas the influence of the injection volume and injection position was not substantial. An in vitro-in vivo correlation (IVIVC) study was developed using griseofulvin suspension to explore the feasibility of applying ESCAR in formulation development and bioequivalence studies. The developed LEVEL A IVIVC model demonstrated that the in vivo PK profile could be correlated with the in vitro release profile. Therefore, using this model, for new formulations, only in vitro studies need to be conducted in ESCAR, and in vivo studies might be waived. In conclusion, ESCAR had important implications for research and development and quality control of SC drug products. Future work would be focused on further optimizing ESCAR and expanding its applications via assessing more types of molecules and formulations.

Pharmacokinetics and bioavailability of tildipirosin following intravenous and subcutaneous administration in sheep.

Tildipirosin is a semi-synthetic macrolide antibiotic commonly used in cattle and swine to treat bacterial pneumonia. The objective of this study was to investigate the pharmacokinetic profile of tildipirosin after a single intravenous (i.v.) and subcutaneous (s.c.) administration in healthy lambs. Eighteen lambs were randomly divided into three groups (n = 6 each). Lambs received a single s.c. dose of tildipirosin at 4 and 6 mg/kg b.w. in group 1 and 2, respectively. Lambs in group 3 received a single i.v. dose of tildipirosin at 4 mg/kg b.w. Blood samples were collected at 0, 0.5, 0.75, 1.5, 2, 3, 4, 6, 8, 10, 24, 36, 48 hr, and every 24 hr to day 21, and thereafter at day 28 posttildipirosin administration. The plasma concentrations of tildipirosin were determined using high-performance liquid chromatography with tandem mass spectrometry detection (LC/MS/MS). All lambs appeared to tolerate both the intravenous and subcutaneous injection of tildipirosin. Following i.v. administration, the elimination half-life (T1/2 ), mean residence time (MRT), volume of distribution (Vd/F), and total body clearance (Cl/F) were 119.6 ± 9.0 hr, 281.9 ± 25.7 hr, 521.1 ± 107.2 L, and 2.9 ± 0.5 L/hr, respectively. No significant differences in Cmax (657.0 ± 142.8 and 754.6 ± 227.1 ng/ml), Tmax (1.21 ± 0.38 and 1.35 ± 0.44 hr), T1/2 (144 ± 17.5, 156.5 ± 33.4 hr), and MRT (262.0 ± 30.2 and 250.6 ± 54.5 hr) were found in tildipirosin after s.c. dosing at 4 and 6 mg/kg b.w., respectively. The absolute bioavailability (F) of tildipirosin was 71.5% and 75.3% after s.c. administration of 4 and 6 mg/kg b.w., respectively. In conclusion, tildipirosin was rapidly absorbed and slowly eliminated after a single s.c. administration in healthy lambs. Tildipirosin could be used for the treatment and prevention of respiratory bacterial infections in sheep. However, further in vitro and in vivo studies to determine the efficacy and safety are warranted. To our knowledge, this is the first study to determine the tildipirosin pharmacokinetic parameters in sheep plasma.

A comparative study of the lengths of different reconstruction routes used after thoracic esophagectomy.

BACKGROUND: A challenge in esophageal reconstruction after esophagectomy is that the distance from the neck to the abdomen must be replaced with a long segment obtained from the gastrointestinal tract. The success or failure of the reconstruction depends on the blood flow to the reconstructed organ and the tension on the anastomotic site, both of which depend on the reconstruction distance. There are three possible esophageal reconstruction routes: posterior mediastinal, retrosternal, and subcutaneous. However, there is still no consensus as to which route is the shortest. METHODS: The length of each reconstruction route was retrospectively compared using measurements obtained during surgery, where the strategy was to pull up the gastric conduit through the shortest route. The proximal reference point was defined as the left inferior border of the cricoid cartilage and the distal reference point was defined as the superior border of the duodenum arising from the head of the pancreas. RESULTS: This study involved 112 Japanese patients with esophageal cancer (102 men, 10 women). The mean distances of the posterior mediastinal, retrosternal, and subcutaneous routes were 34.7 ± 2.37 cm, 32.4 ± 2.24 cm, and 36.3 ± 2.27 cm, respectively. The retrosternal route was significantly shorter than the other two routes (both p < 0.0001) and shorter by 2.31 cm on average than the posterior mediastinal route. The retrosternal route was longer than the posterior mediastinal route in only 5 patients, with a difference of less than 1 cm. CONCLUSION: The retrosternal route was the shortest for esophageal reconstruction in living Japanese patients.

Subcutaneous and sublingual allergen-specific immunotherapy: a tale of two routes.

Summary: Specific immunotherapy is the only treatment acting on the causes and not only on symptoms of respiratory allergy. It was first introduced as subcutaneous immunotherapy (SCIT) with the aim to induce immunological tolerance to the administered allergen(s). In the 1980s, sublingual immunotherapy (SLIT) was developed, mainly to improve the safety, which was a critical issue at that time. This article reviewed the available literature, including a large number of randomized controlled trials, meta-analyses, and real-life studies as well, on the outcomes of SCIT and SLIT concerning the treatment critical issues of the two routes, that are efficacy, safety, cost-effectiveness, and compliance to treatment. The efficacy of SCIT and SLIT is similar in respiratory allergy, providing, based on the induction of typical changes in the immunologic response, an early control of symptoms that steadily increases during the treatment and its efficacy lasts after the recommended duration of three years. Such results are the reason why SCIT and SLIT have economic advantage over symptomatic drugs.

Comparative experimental study of Brucella melitensis and its lipopolysaccharide in mouse model infected via subcutaneous route of exposure.

Brucella melitensis is a major zoonotic pathogen in which lipopolysaccharide (LPS) is believed to play a major role in the diseases pathogenesis. To study the immunopathophysiological aspects, we established a mouse model experimentally infected with whole cell of B. melitensis and its lipopolysaccharide via subcutaneous route of exposure. Eighty four mice, BALB/c, both sexes with equal gender distribution and 6-8 weeks-old were randomly assigned into 3 groups. Group 1 (n = 36) were subcutaneoulsy inoculated with 0.4 mL 109 of B. melitensis while group 2 (n = 36) were subcutaneously challenged with 0.4 mL 109 of LPS. Group 3 (n = 12) was challenged subcuatneously with phosphate buffered saline and served as a control group. Animals were observed for clinical signs, haematological and histopathological analysis for a period of 24 days post-inoculation. Our results revealed that B. melitensis infected group demonstrated significant clinical signs and histopathological evidence than LPS infected group. However, both infected groups showed elevated levels of interleukins (IL-1ß & IL6), antibody levels (IgM & IgG) as early as 3 days post-infection with predominance in LPS infected group. For hormone analysis, low levels of progesterone, estradiol and testosterone were observed in both B. melitensis and LPS challenged groups throughout the study period. Moreover, in B. melitensis infected groups, the organism was re-isolated from the organs and tissues of gastrointestinal, respiratory and reproductive systems; thereby confirming the possible transmission of the disease dynamics. Moreover, LPS stimulated significantly the innate and acquired immune system without significant systemic dysfunction suggesting the potentiality of the protective properties of this component as an alternative vaccine for brucellosis infection. This report is the first detailed investigation comparing the infection progression and host responses in relation to the immunopathophysiological aspects in mouse model after subcutaneous inoculation with B. melitensis and its lipopolysaccharide.

Role of nanotechnology in the prolonged release of drugs by the subcutaneous route.

INTRODUCTION: Subcutaneous physiology is distinct from other parenteral routes that benefit the administration of prolonged-release formulations. A prolonged-release effect is particularly convenient for treating chronic diseases because it is associated with complex and often prolonged posologies. Therefore, drug-delivery systems focused on nanotechnology are proposed as alternatives that can overcome the limitations of current therapeutic regimens and improve therapeutic efficacy. AREAS COVERED: This review presents an updated systematization of nanosystems, focusing on their applications in highly prevalent chronic diseases. Subcutaneous-delivered nanosystem-based therapies comprehensively summarize nanosystems, drugs, and diseases and their advantages, limitations, and strategies to increase their translation into clinical applications. An outline of the potential contribution of quality-by-design (QbD) and artificial intelligence (AI) to the pharmaceutical development of nanosystems is presented. EXPERT OPINION: Although recent academic research and development (R&D) advances in the subcutaneous delivery of nanosystems have exhibited promising results, pharmaceutical industries and regulatory agencies need to catch up. The lack of standardized methodologies for analyzing in vitro data from nanosystems for subcutaneous administration and subsequent in vivo correlation limits their access to clinical trials. There is an urgent need for regulatory agencies to develop methods that faithfully mimic subcutaneous administration and specific guidelines for evaluating nanosystems.

Development of Drug Release Model for Suspensions in ESCAR (Emulator of SubCutaneous Absorption and Release).

We recently developed an in vitro testing system, namely, ESCAR (Emulator of SubCutaneous Absorption and Release). The objective of this work was to investigate drug release behaviors of unmilled and milled suspensions in ESCAR. A mass transport-based model was developed to describe the multi-step drug release process, including drug dissolution, particle settling, drug distribution/partition, and drug permeation through the membrane(s). To address the particle settling effect, a correction factor was included in the model and its value was obtained by data fitting. It was found that, for both suspensions, (i) the experimental data of various dose/formulation combinations could be fit by the developed model; (ii) the dose effect on drug release was offset by the particle settling effect. This model may help to reduce experimental efforts and facilitate subcutaneous suspension formulation development using ESCAR.

What is the best reconstruction procedure after esophagectomy? A meta-analysis comparing posterior mediastinal and retrosternal approaches.

Thoracic esophagectomy is a particularly invasive and complicated surgical procedure, with a reconstruction of the gastrointestinal tract, such as the stomach, jejunum, or colon. The posterior mediastinal, retrosternal, and subcutaneous routes are the three possible esophageal reconstruction routes. Each route has advantages and disadvantages, and the optimal reconstruction route after esophagectomy remains controversial. Additionally, the best anastomotic techniques after esophagectomy in terms of location (Ivor Lewis or McKeown) and suturing (manual or mechanical) are debatable. Our meta-analysis investigating postoperative complications after esophagectomy between the posterior mediastinal and retrosternal routes revealed that the posterior mediastinal route was associated with a significantly lower anastomotic leakage rate than the retrosternal route (odds ratio = 0.78, 95% confidence interval: 0.70-0.87, p < 0.0001). Conversely, pulmonary complications (odds ratio = 0.80, 95% confidence interval: 0.58-1.11, p = 0.19) and mortality between the posterior mediastinal and retrosternal routes (odds ratio = 0.79, 95% confidence interval: 0.56-1.12, p = 0.19) were not significantly different. However, the incidence of pneumonia may be lower when using the retrosternal route rather than the posterior mediastinal route for performing minimally invasive esophagectomy. The McKeown procedure is oncologically necessary for tumors located above the carina to dissect upper mediastinal and cervical lymph nodes; however, the Ivor Lewis procedure offers perioperative and oncological safety for tumors located under the carina. An individualized treatment strategy for selecting the optimal reconstruction procedure can be proposed in future studies based on oncological and patient risk factors considering mid- to long-term quality of life.

Subcutaneous pantoprazole in an elderly, palliative care patient.

Proton pump inhibitors (PPIs) have become the agents of choice for acid-related diseases. In some clinical situations, PPI therapy by oral or intravenous route may be difficult especially among elderly and patients in palliative care. Off-label PPI subcutaneous injection could be the last alternative to improve patient relief, despite limited published data. We report a case of linitis plastica, peritoneal carcinomatosis and occlusive syndrome who suffered from painful regurgitations which rapidly improved after subcutaneous pantoprazole. No related adverse effects were observed during PPI therapy. Despite some limitations, this report suggests that off-label subcutaneous pantoprazole could be an interesting alternative route when intravenous infusion may be difficult or harmful for elderly and patients in palliative care. Nevertheless, clinical safety and efficiency data on larger populations are needed to validate this use in such population.

Subcutaneous IL-6 Inhibitor Sarilumab vs. Standard Care in Hospitalized Patients With Moderate-To-Severe COVID-19: An Open Label Randomized Clinical Trial.

Background: The use of IL-6 blockers in COVID-19 hospitalized patients has been associated with a reduction in mortality compared to standard care. However, many uncertainties remain pertaining to optimal intervention time, administration schedule, and predictors of response. To date, data on the use of subcutaneous sarilumab is limited and no randomized trial results are available. Methods: Open label randomized controlled trial at a single center in Spain. We included adult patients admitted with microbiology documented COVID-19 infection, imaging confirmed pneumonia, fever and/or laboratory evidence of inflammatory phenotype, and no need for invasive ventilation. Participants were randomly assigned to receive sarilumab, a single 400 mg dose in two 200 mg subcutaneous injections, added to standard care or standard care, in a 2:1 proportion. Primary endpoints included 30-day mortality, mean change in clinical status at day 7 scored in a 7-category ordinal scale ranging from death (category 1) to discharge (category 7), and duration of hospitalization. The primary efficacy analysis was conducted on the intention-to-treat population. Results: A total of 30 patients underwent randomization: 20 to sarilumab and 10 to standard care. Most patients were male (20/30, 67%) with a median (interquartile range) age of 61.5 years (56-72). At day 30, 2/20 (10%) patients died in the sarilumab arm vs. none (0/10) in standard care (Log HR 15.11, SE 22.64; p = 0.54). At day 7, no significant differences were observed in the median change in clinical status (2 [0-3]) vs. 3 [0-3], p = 0.32). Median time to discharge (days) was similar (7 [6-11] vs. 6 [4-12]; HR 0.65, SE 0.26; p = 0.27). No significant differences were detected in the rate of progression to invasive and noninvasive mechanical ventilation. Conclusions and Relevance: Our pragmatic pilot study has failed to demonstrate the benefit of adding subcutaneous sarilumab to standard care for mortality by 30 days, functional status at day 7, or hospital stay. Findings herein do not exclude a potential effect of sarilumab in severe COVID-19 but adequately powered blinded randomized phase III trials are warranted to assess the impact of the subcutaneous route and a more selected target population. Trial Registration: www.ClinicalTrials.gov, Identifier: NCT04357808.

Subcutaneous Administration: Evolution, Challenges, and the Role of Hyaluronidase.

BACKGROUND: The subcutaneous (SC) route has evolved significantly. More than two dozen chemotherapy and supportive therapies have been approved for use in the oncology setting. Several IV therapies have been approved for the SC route and require a significantly higher volume than historical maximum limits. Differences exist in how these drugs are administered as compared to older chemotherapy agents. OBJECTIVES: The purpose of this article is to provide a brief history of the SC route and describe its role in cancer treatment. The use of recombinant hyaluronidase is reviewed within the context of SC monoclonal antibodies. Proper administration techniques and interventions for reducing patient discomfort are discussed. METHODS: Sentinel medical texts, pharmacokinetic studies, manufacturer's recommendations, and peer-reviewed articles were examined. FINDINGS: The SC route offers several advantages over the oral and IV routes. A clear understanding of anatomical site selection and injection techniques is beneficial for providing requisite patient education.

Pharmacokinetics of Subcutaneous Levetiracetam in Palliative Care Patients.

Background: Seizure control is challenging in the palliative care setting. Subcutaneous (SC) levetiracetam (LEV) is currently an off-label route of administration and effectiveness, tolerability, and pharmacokinetics studies for this route are scarce. Objectives: This prospective study aimed at evaluating effectiveness and tolerability of SC LEV as well as characterizing its pharmacokinetics. Subjects: Patients (n = 7) who attended the palliative care clinic between September 2018 and January 2019 with diagnosis of seizures, ≥18 years, and in need of SC route of administration were included in the study. Measurements: LEV plasma levels were determined using high-performance liquid chromatography and pharmacokinetic analysis were performed using Monolix 2018R2 (France). pH and osmolality of the three SC infusion solutions were also determined. Results: Seven patients took part in the study. Seizures were controlled in six out of seven patients with doses of 1000 and 3000 mg/day. Adverse effects were mild. pH and osmolality of the SC infusion solutions were within the accepted values reported in the literature. Mean plasma LEV concentrations were 14.4 mg/L (1000 mg/day) and 27.7 mg/L (2000 mg/day). The population clearance (2.5 L/h) and the elimination half-life (10.4 hours) were successfully estimated. Conclusions: Based on this data, SC LEV was effective and well tolerated. Pharmacokinetic parameters for the SC route were successfully determined.

Efficacy and safety of subcutaneous administration of ceftazidime as a salvage therapy in geriatrics: a case report.

Ceftazidime is a third-generation cephalosporin used for the treatment of Gram-negative bacteria only approved for parenteral use by intravenous and intramuscular route. In some clinical situations, off-label subcutaneous injection could be a salvage route for the administration of antibiotics, especially in geriatrics, despite the paucity of evidence about efficacy and safety. We report a case of a successful and well-tolerated subcutaneous ceftazidime therapy in a 90-year-old woman for the treatment of an acute urinary tract infection caused by Pseudomonas aeruginosa with therapeutic drug monitoring data.

Allergen immunotherapy for respiratory allergy: to what extent can the risk of systemic reactions be reduced?

INTRODUCTION: Allergen immunotherapy is an effective treatment for respiratory allergy, but the administration to patients of extracts of the causative allergen may elicit systemic reactions, which include, particularly with subcutaneous immunotherapy (SCIT), anaphylaxis. In the past, the occurrence (tough rare) of fatal reactions has represented a serious problem that has limited the prescription of SCIT. AREAS COVERED: The authors analyzed in this review the safety data of SCIT, especially concerning the years following the identification of uncontrolled asthma at the moment of allergen injection as the major risk of life-threatening reactions and fatalities. The safety of SLIT, which is far better than SCIT, was analyzed and its specific risk factors for systemic reactions were highlighted. EXPERT OPINION: Presently, the safety profile of SCIT and SLIT is satisfactory, provided the treatment is administered by physicians experienced in this treatment, who are aware of the known risk factors for severe reactions and who implement all measures to avoid them. For SLIT, which is self-administered by the patient, receiving the first dose under medical control is recommended.

Intravenous versus subcutaneous route pharmacokinetics of paracetamol (acetaminophen) in palliative care patients: study protocol for a randomized trial (ParaSCIVPallia).

BACKGROUND: Among palliative care (PC) patients who are administered paracetamol, the subcutaneous (SC) route is often an alternative to the intravenous (IV) route. Yet pharmacological and clinical data on whether these are equivalent pharmacokinetically are lacking. Many French palliative teams are now empirically using paracetamol by the SC route, but there are no data to support this practice. This trial aims to compare the pharmacokinetic (PK) parameters of paracetomol between the IV and SC routes in PC patients. METHODS/DESIGN: This is a randomized, open, crossover study in two PC centers. The primary endpoints are AUC0-t, AUC0-∞, Cmax, Vd, and t1/2. All adverse events will be reported for a safety analysis. Twenty adult PC patients with an IV device having spontaneous pain not related to care, with a numeric pain rate scale > 3/10, or having a systematic prescription of paracetamol as the usual treatment will be included. All patients also have to meet all eligibility criteria. CONCLUSION: This is the first study comparing PK parameters for IV paracetamol versus SC paracetamol in PC patients. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03944044. Registered on 4 June 2019. Committee for the protection of persons (CPP) 18.09.05.58206 approval 4 October 2018. National Drug Safety Agency (ANSM; Agence Nationale de Sécurité Médicament) MEDAECNAT-2018-09-00009 approval 29 November 2018.

A field study on the efficacy of ivermectin via subcutaneous route against chewing lice (Bovicola caprae) infestation in naturally infested goats.

Caprine pediculosis is an ectoparasitic disease of great concern among goat farmers in India. It may be caused by either sucking lice or chewing lice; the latter one results in severe skin lesions, leading to production loss. This study evaluated the effectiveness of the macrocytic lactone drug, ivermectin, administered via subcutaneous injection, against chewing lice Bovicola (Damalinia) caprae infestation in naturally infested goats. The study was conducted on 20 goats with severe B. caprae infestation. Animals of group A (n = 10) were treated using a single dose of ivermectin (200 µg/kg body weight) subcutaneously and animals of group B (n = 10) underwent placebo therapy using normal saline. The animals were examined on days 0, 3, 7, 14, 21, 28, 42 and 56 for lice counts. There was 100% elimination of lice in all animals of group A and effective protection from re-infection remained at least for 21 days. Considerable improvement in haematological parameters was also observed by day 21. Based on this study, ivermectin injected via a subcutaneous route can be used effectively for the therapeutic and prophylactic management of chewing lice infestation in goats maintained under an extensive grazing system.

The route of Besnoitia besnoiti tachyzoites inoculation does not influence the clinical outcome of the infection in calves.

In a previous attempt, an experimental model of bovine besnoitiosis was established in calves that were intravenously inoculated with different doses of Besnoitia besnoiti tachyzoites. Despite the fact that all infected calves developed the acute stage of disease, only microscopic findings characteristic of chronic besnoitiosis were reported. In the present study, calves were inoculated by subcutaneous and intradermal routes with B. besnoiti tachyzoites with the aim of developing clinical signs and macroscopic lesions characteristic of chronic besnoitiosis. Nine 3-month-old male calves were randomly distributed into three groups of three animals each. Next, 106 tachyzoites were inoculated by either the subcutaneous (G1) or intradermal route (G2). The negative control group (G3) was inoculated with PBS. Daily clinical monitoring and regular blood collection were performed. At 70 days post-infection (pi), animals were euthanized, and tissues were collected to investigate lesions and parasites. Infected animals developed mild-moderate acute besnoitiosis characterized by lymphadenopathy from four days to 47 days pi, and sporadic fever peaks were only observed in one calf from G2. However, other clinical signs and macroscopic lesions characteristic of chronic besnoitiosis were not detected. Only nine tissue samples were B. besnoiti-DNA-positive, eight of which belonged to reproductive and respiratory tracts tissues from G1. Finally, the kinetics of the immune responses were similar in both infected groups. However, delayed and lower cellular and humoral immune responses were observed in G1 followed by G2 and were compared with intravenously inoculated calves. The differences observed among the three inoculation routes could be due to different effector mechanisms of the host early innate immune response against B. besnoiti. Accordingly, the inoculation route of B. besnoiti tachyzoites does not significantly influence the clinical outcome of the infection in calves. Thus, a further refinement of this experimental model of bovine besnoitiosis is needed to reproduce macroscopic lesions characteristic of chronic stage disease.

How to Get the Most from Methotrexate (MTX) Treatment for Your Rheumatoid Arthritis Patient?-MTX in the Treat-to-Target Strategy.

Methotrexate (MTX) is a remarkable drug with a key role in the management of rheumatoid arthritis (RA) at every stage of its evolution. Its attributes include good overall efficacy for signs and symptoms, inhibition of structural damage and preservation of function with acceptable and manageable safety, a large dose-titratable range, options for either an oral or parenteral route of administration, and currently unrivalled cost-effectiveness. It has a place as a monotherapy and also as an anchor drug that can be safely used in combination with other conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) or used concomitantly with biological DMARDs or targeted synthetic DMARDs. MTX is not without potential issues regarding toxicity, notably hepatotoxicity and bone marrow toxicity, as well as tolerability problems for some, but not all, patients. But many of these issues can be mitigated or managed. In the face of a welcome expansion in available targeted therapies for the treatment of RA, MTX looks set to remain at the foundation of pharmacotherapy for the majority of people living with RA and other inflammatory rheumatic diseases. In this article, we provide an evidence-based discussion as to how to achieve the best outcomes with this versatile drug in the context of a treat-to-target strategy for the management of RA.

The STING activator c-di-AMP exerts superior adjuvant properties than the formulation poly(I:C)/CpG after subcutaneous vaccination with soluble protein antigen or DEC-205-mediated antigen targeting to dendritic cells.

Vaccination is the most efficient strategy to protect from infectious diseases and the induction of a protective immune response not only depends on the nature of the antigen, but is also influenced by the vaccination strategy and the co-administration of adjuvants. Therefore, the precise monitoring of adjuvant candidates and their immune modulatory properties is a crucial step in vaccine development. Here, one central aspect is the induction of appropriate humoral and cellular effector mechanisms. In our study we performed a direct comparison of two promising candidates in adjuvant development, the STING activator bis-(3,5)-cyclic dimeric adenosine monophosphate (c-di-AMP) and the Toll-like receptor ligand formulation poly(I:C)/CpG. These were evaluated in C57BL/6 mice using the model antigen ovalbumin (OVA) in subcutaneous vaccination with soluble protein as well as in a dendritic cell (DC) targeting approach (αDEC-OVA). Strikingly, c-di-AMP as compared to poly(I:C)/CpG resulted in significantly higher antigen-specific IgG antibody levels when used in immunization with soluble OVA as well as in antigen targeting to DC. In vaccination with soluble OVA, c-di-AMP induced a significantly stronger CTL, Th1 and IFNγ-producing CD8+ memory T cell response than poly(I:C)/CpG. The response was CTL and Th1 cell dominated, a profile shared by both adjuvants. In the context of targeting OVA to DC, c-di-AMP induced significantly increased Th1 and Th2 cell responses as compared to poly(I:C)/CpG. Interestingly, the Th1 response dominated the overall T cell response only when c-di-AMP was used, indicating a distinct modulatory property of c-di-AMP when the DC targeting immunization approach was exploited. Taken together, we describe superior properties of c-di-AMP as compared to poly(I:C)/CpG in subcutaneous vaccination with soluble antigen as well as antigen targeting to DC. This indicates exceptionally effective adjuvant properties for c-di-AMP and provides compelling evidence of its potential for further adjuvant development, especially also when using DC targeting approaches.