Safety and efficacy of RT234 vardenafil inhalation powder on exercise parameters in pulmonary arterial hypertension: phase II, dose-escalation study design

BACKGROUND

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by high mean pulmonary arterial pressure (≥ 20 mmHg) and remodeling of the vascular arteries. Approved therapies improve symptoms and delay clinical worsening in the long term, but they do not relieve acute exertional symptoms. RT234, a drug/device combination (Respira Therapeutics, Palo Alto, CA, USA) that delivers the phosphodiesterase 5 inhibitor vardenafil to the lungs via inhalation, has been shown to reduce pulmonary vascular resistance in patients with PAH. This study aims to evaluate whether RT234 can increase oxygen capacity during cardiopulmonary exercise testing (CPET) in patients with PAH.

METHODS

This prospective, multi-center, open-label, two-cohort, dose-escalation, phase IIb trial in patients with PAH will evaluate the safety and efficacy of RT234 in improving exercise parameters. The trial began in September 2020 and is expected to be completed by early 2024. Patients eligible for enrollment will have a right heart catheterization-confirmed diagnosis of PAH, a 6-minute walking distance of ≥ 150 m, a minute ventilation/carbon dioxide production slope of ≥ 36, and will be on up to three stable oral and/or inhaled (not parenteral) PAH-specific background therapies. The estimated sample size is 86 patients, who will be divided into two dose cohorts. Cohort 1 will receive 0.5 mg RT234, and cohort 2 will receive 1.0 mg RT234. Each cohort will contain two subgroups based on the number of PAH background medications (up to two vs three). The trial will assess patients' changes from baseline in peak oxygen consumption (VO₂) during CPET 30 minutes after a single dose of 0.5 mg or 1.0 mg RT234, the change in the 6-minute walking distance, and the pharmacokinetics and safety profile of single doses of RT234.

CONCLUSION

This is the first trial involving an as-needed medication for PAH. The trial will provide insights into the safety and efficacy of as-needed RT234 in treating the acute symptoms of PAH during exercise and will inform the design of further trials.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov identifier NCT04266197.

Selonsertib in adults with pulmonary arterial hypertension (ARROW): a randomised, double-blind, placebo-controlled, phase 2 trial

BACKGROUND

Data obtained in human lung tissue and preclinical models suggest that oxidative stress and increased apoptosis signal-regulating kinase 1 (ASK1) activity might have a prominent role in the pathobiology of pulmonary arterial hypertension (PAH). The purpose of this study was to determine the efficacy, safety, and tolerability of the ASK1 inhibitor selonsertib compared with placebo in patients with PAH.

METHODS

We did a randomised, double-blind, placebo-controlled, phase 2 trial at 46 centres located in Canada, France, Germany, Italy, the Netherlands, Spain, the UK, and the USA. Participants were aged 18-75 years and had an established diagnosis of idiopathic or hereditary PAH, or PAH associated with connective tissue disease, drugs or toxins, human immunodeficiency virus, or repaired congenital heart defects. Patients were stratified by PAH aetiology and background therapy, and randomly assigned (1:1:1:1) using an interactive voice-response or web-response system to placebo or selonsertib 2 mg, 6 mg, or 18 mg administered orally once daily. Both placebo and selonsertib were in tablet form. The primary efficacy endpoint was change in pulmonary vascular resistance, measured by right heart catheterisation, from baseline to week 24 in the full analysis set. Pair-wise comparisons between each of the selonsertib groups and the placebo group were made with a stratified Wilcoxon (van Elteren) rank sum test for participants without major protocol deviations who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov, NCT02234141.

FINDINGS

Between Dec 3, 2014, and Nov 13, 2015, 151 patients were enrolled and randomly assigned. Of 150 participants who received selonsertib or placebo, 134 (89%) completed 24 weeks of the randomly assigned treatment; all were on background PAH therapy (138 [92%] on combination therapy). 90 (60%) patients were in functional class II and 60 (40%) in functional class III. Mean baseline pulmonary vascular resistance was 772 (SD 334) dyn·s/cm⁵. Change in pulmonary vascular resistance was 6·0 dyn·s/cm⁵ (SD 28·0; n=31) for placebo, and 35·0 (35·4) dyn·s/cm⁵ (n=35; p=0·21 vs placebo) for 2 mg selonsertib, -28·0 (30·2) dyn·s/cm⁵ (n=34; p=0·27 vs placebo) for 6 mg selonsertib, and -21·0 (37·9) dyn·s/cm⁵ (n=36; p=0·60 vs placebo) for 18 mg selonsertib. The most frequent adverse events were headache (17 [15%]), abnormal dreams (eight [7%]), nausea (seven [6%]), and diarrhoea (seven [6%]) in the selonsertib groups, and headache (six [16%]), nausea (five [14%]), and diarrhoea (two [5%]) in the placebo group. Serious adverse events occurred in 23 (20%) of 113 selonsertib-treated patients and seven (19%) of 37 patients who received placebo.

INTERPRETATION

Selonsertib once daily for 24 weeks did not lead to a significant reduction in pulmonary vascular resistance or to clinical improvement in patients with PAH, but appeared to be safe and well tolerated. Although these data do not support the clinical use of selonsertib in PAH, further study of the potential of targeting the ASK1-p38 pathway in PAH is warranted.

FUNDING

Gilead Sciences.

Reassessing Phase II Heart Failure Clinical Trials: Consensus Recommendations

The increasing burden and the continued suboptimal outcomes for patients with heart failure underlines the importance of continued research to develop novel therapeutics for this disorder. This can only be accomplished with successful translation of basic science discoveries into direct human application through effective clinical trial design and execution that results in a substantially improved clinical course and outcomes. In this respect, phase II clinical trials play a pivotal role in determining which of the multitude of potential basic science discoveries should move to the large and expansive registration trials in humans. A critical examination of the phase II trials in heart failure reveals multiple shortcomings in their concept, design, execution, and interpretation. To further a dialogue on the challenges and potential for improvement and the role of phase II trials in patients with heart failure, the Food and Drug Administration facilitated a meeting on October 17, 2016, represented by clinicians, researchers, industry members, and regulators. This document summarizes the discussion from this meeting and provides key recommendations for future directions.

Emotional arousal enhances declarative memory in patients with Alzheimer's disease

OBJECTIVE

To verify whether the long-term retention of an emotionally arousing story is stronger than the retention of a neutral story, and the enhancing effects of emotional arousal on declarative memory in Alzheimer's disease (AD) patients.

METHOD

Twenty subjects (10 with AD and 10 controls matched for age and educational level) were studied. After the audiovisual presentation (neutral story), the subjects rated the narrative's emotionality. Later, they answered a multiple-choice questionnaire about the stories. Two weeks later, they watched the emotionally arousing story.

RESULTS

Subjects who watched the emotionally arousing story assigned a score of emotionality higher than the subjects in the neutral group (P = 0.023). In addition, the participants remembered more details of the arousing story, and had a higher score in the questionnaire (P < 0.001).

CONCLUSIONS

We demonstrated that an emotionally arousing content enhances long-term declarative memory in AD. Furthermore, present finding supports the use of this instrument for clinical and research purposes.

Incremental reductions of positive charge within the S4 region of a voltage-gated K+ channel result in corresponding decreases in gating charge

The S4 region of voltage-dependent ion channels is involved in the voltage-sensing mechanism of channel activation. Previous studies in fast inactivating channels have used non-steady-state measurements and thus have not allowed the quantitative assessment of activation parameters. Using site-directed mutagenesis and voltage-clamp recordings in a noninactivating channel (RCK1), we demonstrate that stepwise reductions of positive charge within the S4 region correlate with a progressive decrease in the channel's overall gating valence. In addition to testing for electrostatic behavior of individual charged residues, our study was designed to probe nonelectrostatic influences on charge movement. We provide evidence that individual charged residues behave differentially in response to the electric field, so that purely electrostatic influences cannot fully account for the gating movement of certain charges.