ATS: phase 2 data demonstrate the superiority of efdoralprin alfa over a standard-of-care augmentation therapy in achieving higher fAAT levels in AATD

Sanofi's Efdoralprin Alfa Shows Superiority in AATD Phase 2 Study

Sanofi announced positive results from the global ElevAATe Phase 2 study, demonstrating the superiority of investigational efdoralprin alfa over standard-of-care plasma-derived augmentation therapy (pdAAT) in adult patients with alpha-1 antitrypsin deficiency (AATD)-related emphysema. Dosed every three weeks (Q3W), efdoralprin alfa achieved mean increases in functional AAT (fAAT) trough levels more than three times greater than weekly pdAAT, meeting the primary endpoint (p<0.0001). The study also showed that fAAT levels remained above the normal threshold for 100% of days in the Q3W arm over 32 weeks, compared to 41% for pdAAT, with a comparable safety profile.

• Superior Efficacy in fAAT Normalization: The ElevAATe study's primary endpoint was met with high statistical significance (p<0.0001), showing efdoralprin alfa dosed every three weeks (Q3W) increased mean fAAT trough levels by 24.1μM, more than three times the 7.6μM increase seen with weekly plasma-derived augmentation therapy (pdAAT). This demonstrates a significant improvement in restoring and maintaining functional AAT levels.
• Sustained Normal fAAT Levels with Less Frequent Dosing: Efdoralprin alfa Q3W maintained fAAT levels above the normal threshold (23.8 μM) for 100% of days during the 32-week study, a substantial improvement compared to 41% of days for patients on standard-of-care pdAAT. This highlights the potential for efdoralprin alfa to offer a more convenient and effective treatment option with less frequent administration.
• Favorable Safety Profile and Regulatory Designations: Efdoralprin alfa was well tolerated, exhibiting a safety profile comparable to pdAAT, with no participants discontinuing due to treatment-emergent adverse events. Notably, the incidence of grade ≥2 COPD exacerbations was numerically lower in the efdoralprin alfa Q3W arm. The drug has also received Fast Track and Orphan Drug designations in the US, and Orphan designation in the EU, underscoring its potential to address an unmet medical need.

Why New AATD-Related Emphysema Treatments Are Urgently Needed

Current treatment approaches for AATD-related emphysema face significant challenges that limit their effectiveness and accessibility. The primary therapeutic option, augmentation therapy, demonstrates biochemical efficacy but has uncertain clinical benefits, while alternative delivery methods and treatment strategies remain underdeveloped. These limitations underscore the urgent need for more effective, targeted therapies for this patient population.

• Limited clinical efficacy of augmentation therapy - While intravenous augmentation therapy raises serum and alveolar AAT levels above putative thresholds, decreased rate of decline in lung function and improved survival remain presumptive, with randomized trials demonstrating biochemical efficacy but lacking adequate power to prove effectiveness in clinical endpoints like quality of life or survival

• Burdensome treatment regimen requirements - Intravenous augmentation therapy requires weekly or biweekly administration for life, representing a significant lifelong commitment that affects patient compliance and quality of life

• Insufficient pulmonary drug delivery - Current intravenous augmentation therapy provides inadequate alpha-1 antitrypsin delivery to the lungs to modify airways inflammation, while inhaled formulations struggle to target the emphysematous lung parenchyma of small alveolated airways where disease occurs

• High variability in treatment decisions - Clinical manifestations are highly heterogeneous making individual prognosis difficult to establish, with great variability in treatment indication even among specialists, creating uncertainty about when to initiate therapy

• Disease progression limitations - Augmentation therapy only slows emphysema progression without stopping it completely and cannot prevent eventual progression to end-stage lung disease, leaving lung transplantation as the only option for advanced cases

• Inadequate biomarkers and endpoints - Studies encounter high interindividual variability in outcomes, with traditional endpoints proving insufficient, highlighting the need for better biomarkers to identify patients with rapidly declining lung function

• Diagnostic and knowledge gaps - AATD remains under-recognized with long diagnostic delays and generally low knowledge levels among healthcare providers, with mean test scores of only 54% for physicians and 52% for respiratory therapists

ElevAATe Phase 2: Efdoralprin Alfa's Design and Efficacy Highlights

Multiple landmark trials have evaluated treatment approaches and disease progression in AATD-related emphysema, employing diverse study designs ranging from randomized controlled trials to large observational registries. These studies have established key endpoints including CT densitometry, lung function parameters, and clinical outcomes that form the foundation for current therapeutic development.

A New Era for Alpha-1 Antitrypsin Augmentation

The recent positive Phase 2 results for Sanofi's efdoralprin alfa mark a potentially transformative moment for patients living with alpha-1 antitrypsin deficiency (AATD)-related emphysema. For decades, augmentation therapy with plasma-derived alpha-1 antitrypsin (pdAAT) has been the only treatment addressing the underlying cause of this progressive lung disease. However, its weekly intravenous administration has presented a significant burden, impacting patient freedom and quality of life. While recent, well-powered studies utilizing sensitive CT densitometry have now confirmed the disease-modifying effect of augmentation therapy in slowing emphysema progression, the challenge of patient adherence due to frequent infusions remains.

Efdoralprin alfa directly addresses these critical issues. By demonstrating a three-fold increase in functional AAT trough levels and maintaining normal levels for 100% of days with a remarkable every-three-week (Q3W) dosing schedule, it offers a profound leap in convenience. This could fundamentally reshape the treatment landscape, potentially leading to improved patient adherence and, consequently, better long-term outcomes. The concept that higher, more sustained AAT levels can yield enhanced biological benefits is supported by studies showing double-dose AAT therapy further reduces protease activity and inflammation.

However, the path forward is not without its considerations. While biochemical superiority is clear, the ultimate clinical benefits—such as a greater slowing of emphysema progression, reduction in exacerbations, or improvements in quality of life—must be robustly confirmed in pivotal Phase 3 trials. Furthermore, given the high cost associated with existing augmentation therapies, Sanofi will need to build a compelling value proposition for efdoralprin alfa to secure favorable market access and reimbursement. The long-term safety profile of this novel, less frequently dosed product will also be under close scrutiny. Should these hurdles be successfully navigated, efdoralprin alfa could not only establish a new standard of care but also open doors to exploring AAT's broader immunomodulatory potential in other AATD manifestations, moving towards a more personalized and patient-centric approach to this complex genetic disorder.