The 40-Year Drought That Two Companies Are Racing to End
For 40 years, the only treatment for alpha-1 antitrypsin deficiency has been weekly IV infusions of the same protein. Now Sanofi and Wave Life Sciences are racing toward fundamentally different solutions, and both just dropped data that suggest the drought is finally ending.
A Disease Stuck in 1985
Imagine getting diagnosed with a genetic condition and being told your treatment options haven't changed since Reagan was in office. That's the reality for roughly 100,000 Americans with alpha-1 antitrypsin deficiency (AATD), a hereditary disorder where a single misspelled gene wreaks havoc on both the liver and the lungs.
The only disease-specific therapy? Weekly IV infusions of purified human protein, dosed at 60 mg/kg, for life. Same drug. Same needle. Same regimen. For four decades.
Now, two companies are sprinting toward what could be the first real breakthrough: Sanofi with a next-generation protein therapy, and Wave Life Sciences with something even more radical, an RNA editor that fixes the typo in real time. Both posted major clinical updates this month, and the data suggest the drought might finally be ending.
The Problem Is Worse Than You Think
AATD works like a double punch. The liver produces a defective version of a protective protein called alpha-1 antitrypsin (AAT). This mutant "Z" protein misfolds, clumps up inside liver cells (causing cirrhosis risk), and never makes it into the bloodstream in sufficient quantities. Without enough functional AAT circulating, the lungs get slowly eaten alive by unchecked enzymes.
Current augmentation therapy addresses only half the problem: it tops up blood AAT levels to protect the lungs, but it does absolutely nothing about the toxic protein piling up in the liver. And it can't reverse damage that's already happened. Think of it like mopping the floor while the pipe is still leaking.
Sanofi's Play: Better Augmentation, Fewer Needles
Sanofi's candidate, efdoralprin alfa (acquired through its $1.7 billion takeover of Inhibrx), is a recombinant AAT fused to an Fc protein fragment. That fusion extends the drug's half-life, meaning patients could infuse every three or four weeks instead of every seven days.
The Phase 2 ElevAATe trial enrolled 97 patients across three arms, comparing efdoralprin alfa (dosed every three weeks and every four weeks) against weekly Zemaira, the current standard. The results were striking.
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Patients on the every-three-week schedule achieved a mean increase from baseline in functional AAT trough levels of 24.1 µM, more than triple the 7.6 µM increase achieved by weekly Zemaira. Even the less frequent four-week arm reached a mean increase from baseline of 16.8 µM. Both sit comfortably within the normal range for healthy individuals.
Sanofi also reported numerically fewer COPD exacerbations in both efdoralprin arms (34.1% and 42.1% versus 44.4% with Zemaira), though the trial wasn't powered to prove that difference definitively. The company is now in FDA discussions about next steps toward registration.
It's a meaningful upgrade: less frequent infusions, much higher protein levels, and a hint of clinical benefit. But it's still IV augmentation. It still doesn't touch the liver problem.
Wave's Gamble: Editing the Mistake at Its Source
Wave Life Sciences is trying something no one has done before in this disease. Their drug, WVE-006, is a subcutaneous injection that hijacks the cell's own editing machinery (a system called ADAR) to correct the single-letter RNA mutation responsible for AATD. It doesn't change DNA permanently; it fixes the message, turning toxic Z-protein instructions into healthy M-protein instructions.
Think of it like autocorrect for your genes, but at the messenger level. The original typo in the DNA stays, but the texts that go out get fixed before they're sent.
The Phase 1b/2a RestorAATion-2 trial has produced remarkable proof-of-concept data. In the 400 mg monthly cohort, patients achieved 13.6 µM total AAT, with 7.98 µM of that being the healthy, edited M-AAT protein. Meanwhile, toxic Z-AAT dropped by 70.5% from baseline in the 200 mg biweekly cohort.
Perhaps most impressive: when three treated patients caught infections, their bodies mounted a natural AAT surge, just like healthy people do. The edited cells responded to inflammation on demand. That's not something IV augmentation can replicate; it's a sign the therapy restores something closer to normal biology.
Wave regained full global rights to WVE-006 from GSK in February 2026 and is now pursuing an accelerated approval pathway with the FDA, with regulatory feedback expected by mid-2026.
Wall Street Liked the Science but Wanted More
Despite the clinical promise, investor reactions to Wave's data have been complicated. Shares dropped roughly 18-22% after mid-stage results last year because AAT levels, while clinically meaningful, fell just short of some analysts' internal targets.
Truist Securities noted the 11.9 µM result from an earlier dosing cohort was "exceedingly close" to the investor bogey but missed. Jefferies analyst Roger Song described the data as "narrowly" hitting his positive bar. The narrative crystallized as "a win, but not a knockout."
Other firms pushed back. Leerink Partners argued investors were using outdated expectations. Clear Street raised its Wave price target to $50, viewing the GSK rights return as a positive.
The disconnect highlights a recurring tension in rare disease investing: regulators may be satisfied at one threshold while investors demand a higher number that doesn't necessarily translate to better outcomes for patients.
Two Modalities, One Finish Line
The Sanofi and Wave programs represent genuinely different philosophies. Sanofi is building a better version of the existing approach: higher AAT levels in the blood, less frequent dosing, less treatment burden. It's an evolutionary leap that could become the new standard of care for lung protection.
Wave is attempting a revolution. By correcting the RNA itself, WVE-006 potentially addresses both the lung (restoring functional AAT) and the liver (reducing toxic Z-AAT accumulation) with a single monthly self-injection. No IV. No infusion center. No plasma supply chain.
The trade-off? Sanofi has stronger Phase 2 data in a larger trial with a head-to-head win over standard care. Wave has earlier-stage data but a mechanistically superior story. Sanofi's path to Phase 3 looks clearer; Wave's accelerated approval gambit is higher risk, higher reward.
The Bigger Picture
Behind these two programs sits a crowded field: Arrowhead and Takeda's RNAi therapy fazirsiran (with FDA Breakthrough designation for liver disease), Vertex's small-molecule folding correctors, Intellia's CRISPR-based editing approach, and over 40 pipeline drugs in various stages of development.
But Sanofi and Wave are the ones posting data right now, in mid-2026, that could reshape how this disease is treated. For a patient population that has watched the same IV bags drip for 40 years, the race between these two couldn't come fast enough.
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