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Déficit en α1-antitrypsine

Des efforts de recherche récents visant à guérir le déficit en alpha-1-antitrypsine.

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Déficit en α1-antitrypsine

Overview

Alpha-1 Antitrypsin Deficiency (AATD) is an inherited condition in which changes in the SERPINA1 gene reduce the amount of working alpha-1 antitrypsin (AAT), a liver-made protein that protects lung tissue from inflammatory enzymes. In the common severe Pi*ZZ form, the altered “Z-AAT” protein also misfolds and accumulates inside liver cells, creating a dual problem: low protective AAT in the bloodstream and toxic protein buildup in the liver. Lung disease, usually emphysema or chronic obstructive pulmonary disease (COPD), commonly emerges in adulthood and is substantially accelerated by smoking; liver disease can occur from infancy through adulthood. Prognosis is highly variable, and some nonsmokers remain relatively well, while others develop progressive respiratory failure, cirrhosis, or liver cancer. GeneReviews: Alpha-1 Antitrypsin Deficiency

Current care manages complications rather than correcting the disease. For established emphysema, eligible patients may receive lifelong intravenous augmentation therapy—infusions of purified human AAT—alongside standard COPD care, pulmonary rehabilitation, vaccination, and avoidance of tobacco smoke and relevant occupational exposures. Augmentation can slow loss of lung tissue but does not remove liver Z-AAT deposits or repair the genetic cause. Lung transplantation and liver transplantation remain options for end-stage disease; a liver transplant also restores normal circulating AAT production. GeneReviews: Alpha-1 Antitrypsin Deficiency

Scope of Recent Research (2020–present)

Research since 2020 has become notably more cure-oriented: rather than only replacing missing protein or treating symptoms, investigators are attempting to suppress toxic Z-AAT, correct the Pi*Z mutation in DNA, or temporarily repair its RNA message. The field now includes late-stage RNA interference (RNAi) trials for liver disease and several first-in-human editing programs designed to restore production of normal “M-AAT,” but no therapy is yet approved that cures AATD or has demonstrated long-term prevention of both lung and liver outcomes. BEAM-302 trial record REDWOOD fazirsiran study

Major Breakthroughs and Emerging Therapies

The most consequential advance is in vivo DNA base editing, which chemically changes a single DNA letter without making the double-strand DNA cut used in conventional CRISPR editing. Preclinical work showed that lipid nanoparticles (LNPs) carrying adenine base-editor components could correct the PiZ mutation in mouse liver, raise circulating AAT, and improve liver histology. [Base editing in PiZ mice] Beam Therapeutics’ BEAM-302 translates this concept into the clinic: it uses liver-targeted LNPs to convert the disease-causing PiZ sequence back toward the normal sequence, with the aim of reducing toxic Z-AAT while enabling the liver to make functional M-AAT. BEAM-302 trial record

In a March 2026 company update from the ongoing BEAM-302 Phase 1/2 study, 29 participants had been treated and followed for up to 18 months. In the single-dose 60-mg cohort, mean steady-state total AAT was reported as 16.1 micromolar, with M-AAT representing 94% of circulating AAT and mutant Z-AAT reduced by 84%; the company also reported transient infusion reactions and liver-enzyme elevations, including more substantial but asymptomatic elevations after a second dose in a small multidose cohort. These biomarker results are important proof that permanent correction of liver cells can produce functional AAT, but they are early, sponsor-reported findings rather than definitive evidence of fewer exacerbations, less emphysema, or reversal of fibrosis. BEAM-302 clinical update

A second base-editing approach, YolTech’s YOLT-202, is also designed to repair the Pi*Z mutation in liver cells after a single intravenous administration. In company-reported data presented at the European Respiratory Society Congress on September 7, 2026, YOLT-202 reportedly raised AAT above the protective threshold, maintained expression for six months, and produced predominantly corrected M-AAT in evaluated cohorts. Its investigator-initiated first-in-human study remains small and exploratory, so these findings require peer-reviewed publication, longer follow-up, and confirmation in controlled trials. YOLT-202 trial record YOLT-202 ERS 2026 update

RNA editing offers a potentially repeatable alternative to permanent DNA editing. Wave Life Sciences’ WVE-006 is a subcutaneously delivered, N-acetylgalactosamine (GalNAc)-conjugated oligonucleotide that recruits a naturally occurring RNA-editing enzyme to change PiZ RNA transcripts into messages that can produce M-AAT. In preclinical PiZ mice, a related RNA-editing candidate corrected about half of targeted liver transcripts, increased serum AAT and neutrophil-elastase inhibitory activity, and reduced Z-AAT aggregation and inflammatory signals. [SERPINA1 RNA editing study] In the ongoing RestorAATion-2 clinical study, Wave has reported production of M-AAT, reduction of Z-AAT, and total AAT concentrations near or above the conventional protective threshold in multidose cohorts; unlike DNA editing, however, RNA editing must be redosed because it does not alter genomic DNA. [RestorAATion-2 study summary] [WVE-006 clinical update]

The leading non-curative molecular strategy is RNA interference. Fazirsiran uses a GalNAc-linked small interfering RNA to degrade Z-AAT messenger RNA in hepatocytes, lowering production of the protein that injures the liver. In a 2022 open-label Phase 2 study, liver Z-AAT fell by a median 83.3%, accompanied by improvements in liver inflammation biomarkers and histology. [Fazirsiran Phase 2 study] A subsequent placebo-controlled Phase 2 study found dose-dependent reductions in serum and liver Z-AAT and less hepatic globule burden, with stable pulmonary function during the study period. [SEQUOIA Phase 2 trial] Because RNAi suppresses production of Z-AAT rather than restoring the normal gene or making M-AAT, it is best viewed as a liver-directed disease-modifying approach, not a complete genetic cure. Small-molecule “correctors” have also provided useful proof of mechanism: Vertex’s VX-864 increased functional AAT by roughly 2.2–2.3 micromolar in Phase 2, but the increase was judged too small for substantial clinical benefit and the program did not advance. [VX-864 Phase 2 update]

Clinical Trials and Experimental Approaches

Fazirsiran, now developed by Takeda as TAK-999, is the most advanced liver-directed program. Its Phase 3 REDWOOD trial is a randomized, placebo-controlled study enrolling adults with Pi*ZZ AATD-associated liver disease and METAVIR F2–F4 fibrosis. The principal fibrosis endpoint is based on liver biopsy at week 106, making it a key test of whether dramatic Z-AAT lowering can translate into meaningful reduction of liver scarring rather than biomarker improvement alone. REDWOOD fazirsiran study

BEAM-302 is recruiting in a Phase 1/2 dose-exploration and dose-expansion study for adults with AATD-associated lung disease and/or liver disease, sponsored by Beam Therapeutics; the registry lists estimated primary completion in May 2028. BEAM-302 trial record YOLT-202 is in an early Phase 1, single-dose, dose-escalation study sponsored by RenJi Hospital, with an estimated enrollment of 18 participants and planned long-term follow-up. YOLT-202 trial record WVE-006 is being tested in the open-label Phase 1b/2a RestorAATion-2 study in adults with Pi*ZZ AATD, assessing safety, pharmacokinetics, and pharmacodynamic evidence that RNA correction produces normal AAT. RestorAATion-2 study summary

Methodologies and Scientific Approaches

Researchers use PiZ transgenic mice, patient-derived liver cells, primary human hepatocytes, and early human dose-escalation trials to determine whether a treatment can both reduce intracellular Z-AAT polymers and restore functional AAT in blood. Base-editing studies compare direct correction of the PiZ mutation with compensatory edits that make AAT less likely to misfold; LNPs are the principal delivery vehicle because they preferentially reach hepatocytes after intravenous administration. Base editing in PiZ mice

Clinical studies increasingly measure both sides of AATD biology: total AAT concentration, proportion of corrected M-AAT, functional inhibition of neutrophil elastase, circulating and liver Z-AAT, liver enzymes, biopsy-based fibrosis and globule burden, pulmonary function, and imaging-based lung or liver measures. This dual-organ biomarker strategy is essential because success in the liver does not automatically establish prevention or repair of emphysema. SEQUOIA Phase 2 trial BEAM-302 clinical update

Leading Institutions and Funding

The translational field is led by biotechnology sponsors—Beam Therapeutics, Wave Life Sciences, Takeda, and YolTech—working with clinical centers in North America, Europe, and China. Academic contributors include the University of Massachusetts Chan Medical School, whose investigators coauthored foundational base-editing work with Beam scientists, as well as specialist liver and pulmonary centers participating in fazirsiran and gene-editing trials. Base editing in PiZ mice SEQUOIA Phase 2 trial

The Alpha-1 Foundation remains a major catalyst for investigator-initiated work and clinical infrastructure. Its 2024 annual report states that it directed more than $3.5 million in peer-reviewed research grants during fiscal year 2024 and had invested more than $100 million across 130 institutions worldwide. Alpha-1 Foundation 2024 annual report U.S. National Institutes of Health support also funds mechanistic research, including a 2024 National Heart, Lung, and Blood Institute award focused on proteostasis—the cellular systems that control protein folding, trafficking, and disposal—in AATD. NIH proteostasis award

Strengths, Limitations, and Challenges

The strongest recent advance is that DNA and RNA correction strategies have now shown in humans that Pi*ZZ patients can produce corrected M-AAT, potentially addressing the root cause of both the lung deficiency and liver toxicity. RNAi has also generated unusually strong and reproducible reductions in liver Z-AAT, with biopsy-based evidence that the toxic storage burden can decline. [BEAM-302 clinical update] [SEQUOIA Phase 2 trial]

The limitations are substantial. AATD progresses over years, so short-term increases in AAT or improvements in liver biomarkers cannot yet prove that a therapy prevents emphysema, cirrhosis, transplantation, cancer, or death. Permanent DNA editing raises continuing questions about off-target edits, liver toxicity, immune reactions, durability, redosing, and equitable access to complex one-time therapies; the BEAM-302 multidose cohort illustrates that clinically meaningful liver-enzyme elevations must be carefully monitored. [BEAM-302 clinical update] RNA editing may avoid permanent genomic alteration but likely requires chronic redosing, while RNAi may improve liver disease without restoring the circulating AAT required for lung protection. [SERPINA1 RNA editing study] [Fazirsiran Phase 2 study]

Outlook and Future Directions

À la date du 8 septembre 2026, l’AATD est plus proche d’un traitement potentiellement ciblant la cause première que jamais auparavant, mais il n’est pas encore proche d’un remède prouvé. Les jalons les plus importants sont un suivi durable, revu de façon indépendante, des résultats de BEAM-302 et YOLT-202; des preuves contrôlées que fazirsiran améliore la fibrose prouvée par biopsie; la confirmation que WVE-006 peut maintenir en toute sécurité une production significative de M-AAT avec une posologie pratique; et, surtout, la preuve que ces interventions préservent la fonction pulmonaire et préviennent l’insuffisance hépatique sur plusieurs années. Une correction ponctuelle de l’ADN qui restaure en toute sécurité le M-AAT physiologique tout en éliminant le Z-AAT pourrait être curative pour la maladie Pi*ZZ, mais cette conclusion necessitera des preuves cliniques à long terme — et non purement moléculaires. BEAM-302 trial record REDWOOD fazirsiran study

References

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