Discovery of a highly potent glucocorticoid for asthma treatment

First-in-human study on pharmacokinetics, safety, and tolerability of single and multiple escalating doses of PA9159 nasal spray, a highly potent glucocorticoid in healthy Chinese volunteers

OBJECTIVE

PA9159 (previously named VSG159) is a structurally novel and highly potent glucocorticoid that plays a role in the late development of autoimmune and inflammatory diseases. The current first-in-human ascending-dose study of the PA9159 nasal spray was conducted in healthy Chinese volunteers to evaluate its pharmacokinetics, safety, and tolerability. In addition, the effects of PA9159 on serum cortisol secretion were investigated.

METHODS

This was a double-blinded, randomized, placebo-controlled clinical study that included four single-dose groups in the single ascending dose cohort (SAD) and two multiple-dose groups in the multiple ascending dose cohort (MAD), with dose ranges of 10-80 μg and 20-40 μg, respectively. PA9159 was administered bilaterally via nasal spray once only or once daily for seven days. Pharmacokinetic, safety, and tolerability profiles were evaluated.

RESULTS

A total of 60 participants completed the study. PA9159 doses of up to 80 μg in the SAD and up to 40 μg in the MAD were shown to be safe and tolerable. The most common treatment-related AEs were mild and transient local nasal AEs. Morning serum cortisol levels approximately remained unchanged in both the single-dose and multiple-dose groups. PA9159 was quantified in 41.8 % (368/880) of the samples in all treatment groups, including 25.2 % (105/416) of the SAD and 56.7 % (263/464) of the MAD. The majority (>80.0 %) of PA9159 plasma concentrations ranged from 0.5 to 2 pg/mL in determined samples. The mean AUC0-t of PA9159 in the SAD was 0.91, 1.39±0.68, 11.40±9.91, and 46.30±25.80 h*pg/mL in the 10 to 80 ug single group. The mean terminal half-life time (t1/2) was 8.43 h and 8.97±2.28 h in 40 ug and 80 ug single group, respectively. The mean AUCss of PA9159 in the MAD was 31.70±7.04, 44.20±20.60 h*pg /mL, and the t1/2 was 16.00±4.18 h, 21.20±10.20 h in the 20 ug and 40 ug multiple groups, respectively. The median Tmax was approximately 6 h in both the SAD and MAD cohorts.

CONCLUSIONS

The PA9159 nasal spray was generally safe and well tolerated, and the effects of PA9159 on serum cortisol levels were limited. The plasma concentration and systemic exposure to PA9159 were very low. These findings support the necessity for further clinical studies on PA9159 nasal spray in patients suffering from allergic rhinitis.

Channel Expansion in the Ligand-Binding Domain of the Glucocorticoid Receptor Contributes to the Activity of Highly Potent Glucocorticoid Analogues

Glucocorticoids (GCs) act through the glucocorticoid receptor (GR) and are commonly used as anti-inflammatory and immunosuppressant medications. Chronic GC use has been linked with unwanted complications such as steroid-induced diabetes mellitus (SIDM), although the mechanisms for these effects are not completely understood. Modification of six GC parent molecules with 2-mercaptobenzothiazole resulted in consistently less promoter activity in transcriptional activation assays using a 3xGRE reporter construct while constantly reducing inflammatory pathway activity. The most selective candidate, DX1, demonstrated a significant reduction (87%) in transactivation compared to commercially available dexamethasone. DX1 also maintained 90% of the anti-inflammatory potential of dexamethasone while simultaneously displaying a reduced toxicity profile. Additionally, two novel and highly potent compounds, DX4 and PN4, were developed and shown to elicit similar mRNA expression at attomolar concentrations that dexamethasone exhibits at nanomolar dosages. To further explain these results, Molecular Dynamic (MD) simulations were performed to examine structural changes in the ligand-binding domain of the glucocorticoid receptor in response to docking with the top ligands. Differing interactions with the transcriptional activation function 2 (AF-2) region of the GR may be responsible for lower transactivation capacity in DX1. DX4 and PN4 lose contact with Arg611 due to a key interaction changing from a stronger hydrophilic to a weaker hydrophobic one, which leads to the formation of an unoccupied channel at the location of the deacylcortivazol (DAC)-expanded binding pocket. These findings provide insights into the structure-function relationships important for regulating anti-inflammatory activity, which has implications for clinical utility.

Advances and opportunities in nanoimaging agents for the diagnosis of inflammatory lung diseases

The development of rapid, noninvasive diagnostics to detect lung diseases is a great need after the COVID-2019 outbreak. The nanotechnology-based approach has improved imaging and facilitates the early diagnosis of inflammatory lung diseases. The multifunctional properties of nanoprobes enable better spatial-temporal resolution and a high signal-to-noise ratio in imaging. Targeted nanoimaging agents have been used to bind specific tissues in inflammatory lungs for early-stage diagnosis. However, nanobased imaging approaches for inflammatory lung diseases are still in their infancy. This review provides a solution-focused approach to exploring medical imaging technologies and nanoprobes for the detection of inflammatory lung diseases. Prospects for the development of contrast agents for lung disease detection are also discussed.

Improving the risk-to-benefit ratio of inhaled corticosteroids through delivery and dose: current progress and future directions

INTRODUCTION

Inhaled corticosteroids (ICS) are known to increase the risk of systemic and local adverse effects, especially with high doses and long-term use. Hence, considerable resources are invested to improve pharmacokinetic/pharmacodynamic (PK/PD) properties of ICS, effective delivery systems and novel combination therapies to enhance the risk-to-benefit ratio of ICS.

AREAS COVERED

There is an unmet need for new solutions to achieve optimal clinical outcomes with minimal dose of ICS. This paper gives an overview of novel treatment strategies regarding the safety of ICS therapy on the basis of the three most recent molecules introduced to our everyday clinical practice - ciclesonide, mometasone furoate, and fluticasone furoate. Advances in aerosol devices and new areas of inhalation therapy are also discussed.

EXPERT OPINION

Current progress in improving the risk-to-benefit ratio of ICS through dose and delivery probably established pathways for further developments. This applies both to the improvement of the PK/PD properties of ICS molecules but also includes technical aspects that lead to simplified applicability of the device with simultaneous optimal drug deposition in the lungs. Indubitably, the future of medicine lies not only in the development of new molecules but also in technology and digital revolution.

Structural insights into glucocorticoid receptor function

The glucocorticoid receptor (GR) is a steroid hormone-activated transcription factor that binds to various glucocorticoid response elements to up- or down- regulate the transcription of thousands of genes involved in metabolism, development, stress and inflammatory responses. GR consists of two domains enabling interaction with glucocorticoids, DNA response elements and coregulators, as well as a large intrinsically disordered region that mediates condensate formation. A growing body of structural studies during the past decade have shed new light on GR interactions, providing a new understanding of the mechanisms driving context-specific GR activity. Here, we summarize the established and emerging mechanisms of action of GR, primarily from a structural perspective. This minireview also discusses how the current state of knowledge of GR function may guide future glucocorticoid design with an improved therapeutic index for different inflammatory disorders.

Development of highly potent glucocorticoids for steroid-resistant severe asthma

Clinical application of inhaled glucocorticoids (GCs) has been hampered in the case of steroid-resistant severe asthma. To overcome this limitation, we have developed a series of highly potent GCs, including VSGC12, VSG158, and VSG159 based on the structural insight into the glucocorticoid receptor (GR). Particularly, VSG158 exhibits a maximal repression of lung inflammation and is 10 times more potent than the currently most potent clinical GC, Fluticasone Furoate (FF), in a murine model of asthma. More importantly, VSG158 displays a unique property to reduce neutrophilic inflammation in a steroid-resistant airway inflammation model, which is refractory to clinically available GCs, including dexamethasone and FF. VSG158 and VSG159 are able to deliver effective treatments with reduced off-target and side effects. In addition, these GCs also display pharmacokinetic properties that are suitable for the inhalation delivery method for asthma treatment. Taken together, the excellent therapeutic and side-effect profile of these highly potent GCs holds promise for treating steroid-resistant severe asthma.