First-in-human intrapulmonary intratarget microdosing of a novel dual inflammasome inhibitor of NLRP 1/ NLRP 3 in ex vivo human lungs and patients with interstitial lung disease

This study demonstrates the feasibility and success of a first-in-human Phase 0 intratarget microdosing trial, where a novel dual NLRP1/NLRP3 inflammasome inhibitor (ADS032) was safely delivered directly to the distal airways of interstitial lung disease patients via bronchoscopy, establishing a new human-relevant platform for early pharmacological evaluation of lung therapeutics.

The Gist

The Big Picture: Testing the Key in the Lock Before Building the Car

Imagine you have designed a brand-new key (a new medicine) that you think fits perfectly into a specific lock inside a house (a specific target in the human lung). Usually, to see if it works, you have to build a whole house, fill it with furniture, and then try the key. If it doesn't work, you've wasted a lot of time and money.

This paper describes a "First-in-Human" experiment where scientists tried a smarter approach. Instead of building the whole house first, they used a Phase 0 "Microdosing" strategy. Think of this as sending a tiny, harmless scout (a microdose of the drug) into the house just to see if it can find the lock and stick to it, without actually trying to open the door or change anything inside.

The Drug: ADS032

The "scout" in this story is a drug called ADS032.

• What it does: It is designed to stop a specific alarm system in the body called the "inflammasome" (specifically NLRP1 and NLRP3). When this alarm goes off, it causes inflammation, which is a problem in diseases like Interstitial Lung Disease (scarring of the lungs).
• The Goal: The scientists wanted to see if they could deliver this drug directly into the deep parts of the lung and have it stick to the right cells, rather than just swimming around in the blood.

The Two-Part Experiment

The researchers used two different "test tracks" to see if their plan worked.

1. The "Ghost Lung" Test (Ex Vivo)

Before trying this on real people, they tested the drug on human lungs that had been donated but were kept alive outside the body using a special machine (like a life-support system for a lung).

• The Analogy: Imagine a car engine running on a test bench. You can spray fuel directly into the cylinders to see how it reacts without driving the car on the road.
• What they did: They pumped a tiny amount of the drug (mixed with a glowing dye) into the deep air sacs of these "ghost lungs."
• The Result: They could see the drug being swallowed up by the lung's immune cells (macrophages) within minutes. It was like watching a sponge soak up colored water. This proved the drug could physically reach the right cells in human lung tissue.

2. The Human Test (The "Micro" Trial)

Next, they tried this on 12 real patients who already needed a bronchoscopy (a camera test for their lungs) for their lung disease.

• The Setup: The doctors used a thin tube (bronchoscope) to go down the patient's throat.
  • They sprayed a tiny amount of the drug (100 micrograms—about the weight of a grain of sand) into one side of the lung.
  • They sprayed plain salt water into the other side to act as a control (a "dummy" spray).
• The Safety Check: They wanted to make sure the drug didn't cause any sudden bad reactions.
  • Result: It was completely safe. No patients had any adverse reactions.

The Challenge: The "Cross-Talk" Problem

One of the biggest hurdles in this experiment was contamination.

• The Analogy: Imagine trying to paint one wall of a room blue and the other wall red, but the paint sprayer is so messy that blue paint splatters onto the red wall. If you can't tell which wall is which, your experiment fails.
• What happened: In the first few patients, the drug seemed to show up in the "control" (salt water) side of the lung. This meant the drug was drifting over, making it hard to prove it stayed where it was supposed to.
• The Fix: The team changed their procedure. They removed the scope completely between sprays and flushed the airway. In the later patients, this worked perfectly. The drug stayed in the treated lung, and the control lung remained clean.

The Results: Did the Key Fit?

The scientists looked at the drug in three places: the blood, the fluid washed out of the lungs, and the actual cells scraped from the lung walls.

1. In the Blood: The drug appeared in the blood very quickly (within 30 minutes) but then disappeared. This is good; it means the drug didn't hang around in the body where it might cause side effects elsewhere.
2. In the Lung Fluid: When they washed out the lungs with a large amount of fluid (Bronchoalveolar Lavage), the drug was hard to find because the fluid got mixed up.
3. In the Cells (The Winner): When they used a tiny brush to gently scrape cells from the specific spot where the drug was sprayed, they found the drug inside the cells.
   • The Analogy: It's like sending a letter to a specific house. If you just look at the street (the big fluid wash), you might not see it. But if you go inside the house and check the mailbox (the cells), you find the letter right where it was delivered.

What This Means (According to the Paper)

The paper concludes that this method works. They successfully:

• Delivered a tiny dose of a new drug directly into the deep human lung.
• Proved the drug gets inside the specific cells it is supposed to target.
• Showed that by using small brushes and tiny samples (microlavage) instead of big washes, they can avoid the "cross-talk" problem and see exactly where the drug goes.

Important Note: The paper does not claim that the drug cured the patients' lung disease or that it is ready to be used as a treatment yet. It only claims that the delivery method works and that the drug can reach its target in humans. This is a "Phase 0" study, which is like a dress rehearsal to prove the stage is set before the real show (Phase 1 trials) begins.

Technical Summary

Technical Summary: First-in-Human Intrapulmonary Intratarget Microdosing of ADS032

Problem Statement
The translation of anti-inflammatory therapeutics for respiratory diseases faces significant attrition due to the limited predictive value of preclinical animal models and the inability of systemic administration to achieve sufficient local drug exposure without off-target effects. Consequently, promising candidates are often abandoned before their target engagement can be evaluated in the human lung. While Phase 0 trials offer a framework for early assessment, conventional designs relying on systemic dosing and peripheral sampling fail to provide insight into drug behavior within the target organ. There is a critical need for a human-relevant platform to assess pulmonary drug delivery, cellular uptake, and pharmacology at subtherapeutic doses prior to Phase 1 trials.

Methodology
This study employed an integrated translational pipeline combining ex vivo human lung modeling with a first-in-human Phase 0 intratarget microdosing (ITM) trial.

• Compound Development: The study utilized ADS032, a novel dual NLRP1/NLRP3 inflammasome inhibitor. The drug product was manufactured to Good Manufacturing Practice (GMP) standards, with stability studies confirming a 40-month shelf life. A fluorescent analogue, ADS032–NBD, was synthesized via conjugation with a nitrobenzoxadiazole (NBD) fluorophore for visualization.
• Ex Vivo Validation: Before human trials, experiments were conducted on ex vivo human lungs using a perfusion and ventilation system (EVLP).
  • Cellular Uptake: Primary human alveolar macrophages (AMs) were isolated from ex vivo lungs to confirm that ADS032 inhibits LPS/nigericin-induced IL-1β release.
  • Visualization: ADS032–NBD was administered to the distal alveolar space under real-time alveolar endomicroscopy. Flow cytometry was performed on digested lung tissue to quantify cellular uptake across specific populations (macrophages, neutrophils, lymphocytes, and epithelial cells).
  • Pharmacokinetics: A 100 μg microdose was administered to the right middle lobe. Sequential samples of lung perfusate and distal airway microlavage were collected and analyzed via liquid chromatography–mass spectrometry (LC–MS).
• Clinical Trial (The "Micro" Trial): A single-center, open-label Phase 0 study was conducted in 12 patients with interstitial lung disease (ILD) or bronchiectasis.
  • Intervention: Participants received a single 100 μg (93 μg in the text, 1.5 mL) microdose of ADS032 via bronchoscopy to a distal lung segment. A contralateral segment received saline as an internal control.
  • Sampling: Bronchoalveolar lavage (BAL), distal airway microlavage, and bronchial brushings were collected from both treated and control segments. Peripheral blood was drawn at 30 minutes, 1 hour, and 4 hours post-procedure.
  • Analysis: Samples were analyzed for ADS032 concentrations (LC–MS) and inflammasome-associated biomarkers (IL-1β, TNF, IL-6, IL-18, ATP). Protocol refinements were implemented after the first four participants to minimize cross-contamination between lung segments.

Key Results

• In Vitro/Ex Vivo Efficacy: ADS032 demonstrated concentration-dependent inhibition of IL-1β release in primary human alveolar macrophages (significant at ≥50 μM) without broadly suppressing TNF or IL-6.
• Cellular Uptake: In ex vivo lungs, fluorescent ADS032–NBD was rapidly taken up by alveolar macrophages (CD206⁺/CD163⁺), neutrophils, T cells, and epithelial cells within minutes. Flow cytometry confirmed a distinct fluorescence shift in drug-exposed tissues compared to saline controls.
• Safety: The intrapulmonary microdosing procedure was safe, with no recorded adverse events in the 12 enrolled patients.
• Pharmacokinetics (PK):
  • Plasma: ADS032 was detectable in plasma, peaking at 30 minutes and remaining detectable at 1 hour in most participants, but falling below the limit of detection by 4 hours in all but two.
  • Spatial Resolution: BAL fluid showed evidence of cross-contamination between treated and control lobes. In contrast, distal airway microlavage and bronchial brushings provided superior spatial resolution. ADS032 was detected in five treated-lobe microlavages (mean 36.9 ng/mL) and five treated-lobe brushings, with no detectable drug in corresponding control samples.
• Pharmacodynamics (PD): No significant differences were observed in cytokine levels (IL-1β, TNF, IL-6, IL-18) or ATP between pre- and post-instillation samples or between treated and control segments. The authors attribute this to the subtherapeutic nature of the microdose and the lack of spatial resolution in bulk BAL sampling.

Significance and Claims
The paper claims to establish intrapulmonary intratarget microdosing as a viable, human-relevant platform for the early pharmacological evaluation of lung therapeutics. Key contributions include:

1. Feasibility Demonstration: The study proves that controlled delivery of microdoses to a defined anatomical compartment in the human lung is safe and technically feasible.
2. Methodological Advancement: It highlights that distal airway microlavage and brushing offer superior spatial resolution for intrapulmonary PK assessment compared to traditional BAL, effectively mitigating cross-contamination issues.
3. Translational Platform: By integrating ex vivo human lung perfusion with clinical microdosing, the authors provide a pipeline to assess drug delivery, cellular uptake, and target engagement in humans before committing to Phase 1 trials.
4. Compound Validation: The study provides early human data supporting the progression of ADS032, a dual NLRP1/NLRP3 inhibitor, toward Phase 1 evaluation, citing favorable uptake in myeloid cells and a lack of acute safety signals.

The authors conclude that while this Phase 0 study is not designed to assess clinical efficacy, it successfully de-risks the progression of lung-directed therapies by enabling direct, early assessment of pharmacology in the human lung, potentially reducing late-stage clinical attrition.