Alpha-1 Antitrypsin Deficiency

Overview

Alpha-1 antitrypsin deficiency (AATD) is an inherited disorder caused by harmful variants in SERPINA1, the gene for alpha-1 antitrypsin (AAT), a liver-made protein that protects lung tissue from enzyme damage. The common severe Pi*ZZ form produces misfolded “Z-AAT”: too little functional AAT reaches the bloodstream and lungs, while abnormal protein can accumulate inside liver cells. This dual mechanism can cause early emphysema or chronic obstructive pulmonary disease (COPD), liver inflammation, fibrosis, cirrhosis, and occasionally liver cancer; risk and prognosis vary substantially with genotype, smoking exposure, alcohol use, and whether lung or liver disease develops. GeneReviews: Alpha-1 Antitrypsin Deficiency

Current care is not generally curative. It includes smoking avoidance, vaccination, standard COPD treatment, pulmonary rehabilitation, monitoring of lung and liver function, and—in selected people with emphysema—weekly intravenous augmentation therapy using donor-derived AAT. Augmentation raises blood AAT but does not correct the defective gene or remove accumulated Z-AAT from the liver. Liver or lung transplantation can be life-saving for end-stage disease; liver transplantation also restores normal AAT production. GeneReviews: Alpha-1 Antitrypsin Deficiency

Scope of Recent Research (2020–present)

Research activity has accelerated sharply since 2020 because AATD is a single-gene disease with a particularly attractive curative target: correcting or replacing the defective liver-produced protein could, in principle, address both liver toxicity and lung vulnerability. The field is now testing permanent DNA base editing, reversible RNA editing, RNA interference to lower toxic Z-AAT, and protein-folding correctors. The first human data from gene and RNA editing are encouraging, but durable clinical benefit—especially prevention of emphysema progression, fibrosis, cirrhosis, transplantation, and mortality—has not yet been established. Approaches to Therapeutic Gene Editing in AATD

Major Breakthroughs and Emerging Therapies

DNA base editing is the clearest potentially one-time curative strategy. Adenine base editors can convert the disease-causing PiZ DNA letter back toward the normal sequence without making a double-strand DNA break. In 2021, investigators corrected the PiZ mutation in patient-derived induced pluripotent stem cells and liver-like cells, reducing intracellular AAT accumulation, increasing secretion, and lowering cellular stress; whole-genome sequencing in that study did not identify off-target genomic mutations. Base editing in patient iPSC-hepatocytes In 2022, a separate preclinical study showed that lipid nanoparticles carrying base-editing components produced durable liver editing in PiZ-transgenic mice, increased circulating AAT, and improved liver histology. Base editing in PiZ mice

Beam Therapeutics’ BEAM-302 has moved this concept into people. The intravenous lipid-nanoparticle treatment is designed to correct the PiZ E342K mutation in liver cells, enabling production of normal “M-AAT” while reducing mutant Z-AAT. In its ongoing Phase 1/2 study, Beam reported in March 2026 that a single 60 mg dose produced a mean steady-state total AAT concentration of 16.1 µM, with corrected M-AAT comprising 94% of total circulating AAT and mean Z-AAT reduced by 84%; the company reported follow-up of up to 12 months in that dose cohort. These are sponsor-reported interim biomarker data rather than yet-published clinical-outcome data, but they represent the first human evidence that in vivo DNA correction can restore substantial functional AAT production. BEAM-302 Phase 1/2 update

RNA editing offers a reversible alternative to DNA editing. Rather than changing DNA, RNA-editing drugs temporarily repair the mutant SERPINA1 messenger RNA, allowing liver cells to make normal M-AAT protein while treatment continues. In 2026, preclinical researchers reported that a GalNAc-conjugated RNA-editing oligonucleotide corrected about half of Z-AAT transcripts in a PiZ mouse model, increased functional AAT, decreased Z-AAT aggregation, and reduced inflammatory gene-expression changes. RNA editing for AATD Wave Life Sciences’ WVE-006, a subcutaneously delivered GalNAc RNA-editing oligonucleotide, reported Phase 1b/2a interim data in May 2026: in the 200 mg every-two-week cohort, M-AAT made up 64% of total AAT, Z-AAT fell by 71%, and total AAT reached 11.9 µM; effects were also reported with 400 mg monthly dosing. WVE-006 RestorAATion-2 update

RNA interference addresses liver injury but is not a genetic cure. Fazirsiran is a small interfering RNA (siRNA) that lowers SERPINA1 messenger RNA and therefore lowers production of toxic Z-AAT in the liver. In an early study of 16 adults with AATD-associated liver disease, fazirsiran reduced liver Z-AAT by a median 83.3% and cleared or reduced protein globules in liver tissue. Fazirsiran Phase 2 study In the placebo-controlled SEQUOIA Phase 2 trial, serum Z-AAT fell by 61%, 83%, and 94% at week 16 with 25 mg, 100 mg, and 200 mg doses, respectively; liver Z-AAT and globule burden also decreased. SEQUOIA Phase 2 trial Because this approach suppresses protein production rather than repairing the gene, its central unresolved issue is whether liver benefit can be achieved without worsening the lack of protective AAT in the lungs.

Small-molecule correctors have shown proof of mechanism but insufficient effect so far. Vertex’s oral corrector VX-864 was designed to help Z-AAT fold correctly and be secreted. In a Phase 2 study it increased functional AAT by roughly 2.2–2.3 µM over placebo, but Vertex concluded that this increase was unlikely to provide substantial clinical benefit and did not advance the program into late-stage development. VX-864 Phase 2 result

Clinical Trials and Experimental Approaches

BEAM-302 is being evaluated in an open-label Phase 1/2 trial, NCT06389877, sponsored by Beam Therapeutics. The study includes people with AATD-associated lung disease and people with liver disease, with the major near-term question being whether corrected AAT production and reduced Z-AAT remain durable and translate into measurable lung and liver benefit. Beam selected 60 mg for further development and stated in March 2026 that it intended to begin a pivotal cohort in the second half of 2026. BEAM-302 Phase 1/2 update

Fazirsiran, developed by Arrowhead Pharmaceuticals, has advanced from positive Phase 2 biopsy-based studies to the Phase 3 REDWOOD study, NCT05677971, in people with AATD-associated liver disease. Its Phase 2 findings support biological activity against liver Z-AAT accumulation, but Phase 3 must demonstrate that biomarker and histology changes predict clinically meaningful benefit. SEQUOIA Phase 2 trial

RNA editing has produced a more mixed but informative clinical picture. WVE-006 remains in the Phase 1b/2a RestorAATion-2 study and has reported AAT concentrations at or above the commonly used 11 µM protective benchmark in some multidose cohorts. WVE-006 RestorAATion-2 update Korro Bio’s earlier lipid-nanoparticle RNA editor KRRO-110 produced detectable functional M-AAT in treated participants but did not reach the 11 µM threshold after a single dose; Korro subsequently terminated the REWRITE program and pivoted to a preclinical GalNAc-delivered AATD program. Korro AATD program update

Methodologies and Scientific Approaches

Researchers are combining patient-derived induced pluripotent stem cells, differentiated liver-like cells, primary human hepatocytes, PiZ-transgenic mice, and increasingly early human trials to test whether a therapy corrects both arms of AATD biology: liver-cell accumulation of Z-AAT and low circulating functional AAT. Important experimental readouts include gene- or RNA-editing percentage, normal M-AAT and mutant Z-AAT concentrations measured by mass spectrometry, neutrophil-elastase inhibition, liver enzymes, magnetic-resonance or elastography measures, and biopsy findings such as intracellular globules, inflammation, and fibrosis. Base editing in patient iPSC-hepatocytes Fazirsiran Phase 2 study

Delivery technology is central. DNA base editors are packaged as messenger RNA and guide RNA in intravenous lipid nanoparticles that concentrate in liver cells; RNA-editing oligonucleotides can be linked to N-acetylgalactosamine (GalNAc), a sugar that promotes uptake by hepatocytes after subcutaneous dosing. These platforms aim to exploit the liver’s role as the body’s normal AAT factory rather than adding protein externally. Base editing in PiZ mice WVE-006 RestorAATion-2 update

Leading Institutions and Funding

Key academic contributors include Boston University and Boston Medical Center, the University of Massachusetts Chan Medical School, Saint Louis University, and collaborating gene-editing groups. The 2021 patient-cell base-editing study included investigators from Boston University/Boston Medical Center and was supported by NIH awards including R01 DK101501, R01 DK117940, S10 OD021587, and U01 TR001810, as well as a Beam Therapeutics research grant. Base editing in patient iPSC-hepatocytes Beam Therapeutics, Wave Life Sciences, Arrowhead Pharmaceuticals, Vertex Pharmaceuticals, and Korro Bio have been prominent biotechnology developers in the recent therapeutic pipeline. Approaches to Therapeutic Gene Editing in AATD

The Alpha-1 Foundation remains a major nonprofit catalyst for basic, translational, and clinical work. Its fiscal-year 2023 report states that it directed more than $2 million to peer-reviewed research grants, while its current grant mechanisms include pilot awards up to $75,000, career-development awards up to $300,000 over three years, and two-institution research awards up to $400,000. Alpha-1 Foundation research impact report Alpha-1 Foundation grant opportunities

Strengths, Limitations, and Challenges

The major strength of gene and RNA correction is that AATD has a well-defined causal mutation and a measurable biological goal: restore normal functional AAT while reducing toxic Z-AAT. BEAM-302’s human data are especially notable because one intervention has simultaneously increased total and functional AAT, generated corrected M-AAT, and reduced mutant Z-AAT. BEAM-302 Phase 1/2 update RNA therapies may offer a less permanent and potentially adjustable alternative, as illustrated by WVE-006’s reported restoration of M-AAT production and reduction of Z-AAT. WVE-006 RestorAATion-2 update

The limitations are substantial. DNA editing is intended to be permanent, so long-term surveillance must establish editing specificity, durability, immune safety, liver safety, and whether partial correction is enough to prevent real-world lung and liver outcomes. RNA editing requires repeat dosing and remains dependent on sustained delivery and adequate editing efficiency; KRRO-110 illustrates how promising preclinical results may fail to translate into protective AAT levels in people. Korro AATD program update For all approaches, biomarker success is not equivalent to a cure: researchers must show prevention or reversal of emphysema, clinically important fibrosis progression, cirrhosis, transplantation, and premature death, while ensuring equitable access to likely costly specialty treatments.

Outlook and Future Directions

As of October 8, 2026, AATD has no broadly available genetic cure, but it is closer than at any previous point. The most important milestones are longer-term BEAM-302 follow-up and pivotal-study initiation; confirmation that WVE-006 can produce durable, clinically meaningful M-AAT with practical repeat dosing; Phase 3 evidence that fazirsiran improves liver outcomes rather than only Z-AAT biomarkers; and careful long-term safety data for all editing platforms. A true functional cure will require durable correction or replacement of AAT sufficient to protect lungs while eliminating or substantially reducing the liver toxicity created by Z-AAT. BEAM-302 Phase 1/2 update SEQUOIA Phase 2 trial

References

• GeneReviews: Alpha-1 Antitrypsin Deficiency — NCBI Bookshelf, 2022.
• Approaches to Therapeutic Gene Editing in AATD — Gruntman, Xue, and Flotte, 2024.
• Base editing in patient iPSC-hepatocytes — Werder et al., 2021.
• Base editing in PiZ mice — Packer et al., 2022.
• RNA editing for AATD — O’Reilly et al., 2026.
• BEAM-302 Phase 1/2 update — Beam Therapeutics, 2026.
• WVE-006 RestorAATion-2 update — Wave Life Sciences, 2026.
• Fazirsiran Phase 2 study — Strnad et al., New England Journal of Medicine, 2022.
• SEQUOIA Phase 2 trial — Strange et al., Gastroenterology, 2024.
• VX-864 Phase 2 result — Vertex Pharmaceuticals, 2021.
• BEAM-302 clinical trial, NCT06389877 — ClinicalTrials.gov, accessed 2026.
• Fazirsiran REDWOOD clinical trial, NCT05677971 — ClinicalTrials.gov, accessed 2026.
• Korro AATD program update — Korro Bio, 2026.
• Alpha-1 Foundation research impact report — Alpha-1 Foundation, 2023.
• Alpha-1 Foundation grant opportunities — Alpha-1 Foundation, 2026.