aTyr Pharma Provides Regulatory and Clinical Update for Efzofitimod in Pulmonary Sarcoidosis Following FDA Type C Meeting

aTyr Pharma Outlines New Phase 3 Plan for Efzofitimod in Pulmonary Sarcoidosis

aTyr Pharma announced its path forward for efzofitimod in pulmonary sarcoidosis after receiving official minutes from a Type C meeting with the U.S. Food and Drug Administration (FDA). Based on FDA feedback, the company plans to continue development with a new Phase 3 study in patients with chronic, symptomatic pulmonary sarcoidosis with restrictive lung disease. This study will utilize forced vital capacity (FVC) as the primary endpoint and the King’s Sarcoidosis Questionnaire (KSQ)-Lung score as the key secondary endpoint. aTyr Pharma intends to submit an Investigational New Drug (IND) application for this study in June 2026, incorporating an increased dosing frequency of efzofitimod to once every three weeks.

• Following a Type C meeting, aTyr Pharma received FDA feedback indicating that FVC and KSQ-Lung are direct measures of how patients with pulmonary sarcoidosis function and feel. Consequently, the company will prioritize FVC as the primary endpoint for its upcoming Phase 3 study, with KSQ-Lung as the key secondary endpoint, aligning with regulatory guidance for clinically relevant outcomes.
• The planned global, randomized, double-blind, placebo-controlled Phase 3 study is designed to enroll approximately 372 patients with moderate to severe pulmonary sarcoidosis who also present with restrictive lung disease (defined as FVC percent predicted ≤ 80%). Patients will be receiving a stable dose of oral corticosteroids and/or background immunosuppressants, focusing on a specific population where efzofitimod has shown potential benefit.
• The new Phase 3 trial will feature an increased dosing frequency for efzofitimod, administering 5.0 mg/kg intravenously once every three weeks, compared to once every four weeks in previous trials. This strategy aims to enhance drug exposure and potentially improve efficacy, building upon the consistent safety profile observed for efzofitimod in prior clinical studies, while implementing additional risk mitigation.

Why New Options are Crucial for Pulmonary Sarcoidosis Patients

Current treatment approaches for pulmonary sarcoidosis face significant challenges that underscore the urgent need for improved therapeutic options. Treatment protocols remain unstandardized, and the unpredictable disease course with highly variable manifestations means existing therapies are often ineffective across patient populations. These limitations create substantial barriers to optimal patient care and outcomes.

• Lack of standardized treatment protocols and monitoring guidelines - Treatment approaches are not fully standardized, with no consensus on how to monitor disease activity, creating inconsistency in patient management across clinical settings

• Unpredictable disease course with variable treatment response - The disease manifests with highly variable symptoms and unpredictable progression, leading to treatment ineffectiveness in many patients and requiring individualized approaches based on patient heterogeneity

• Limited evidence base from controlled clinical trials - Available information remains limited, particularly for extrathoracic manifestations, with insufficient data from controlled trials to guide evidence-based treatment decisions

• Corticosteroid dependence with significant toxicity burden - New effective therapies are urgently needed to reduce or replace long-term glucocorticoid therapy, as corticosteroid toxicity causes significant morbidity and mortality, particularly in older patients who are more prone to adverse effects

• Inadequate options for severe and refractory disease - A quarter of patients require long-term treatment for chronic disease, and current corticosteroids and cytotoxic agents may be insufficient to control disease in the most severe cases

• Limited access to promising biologics due to regulatory and cost barriers - Anti-TNF monoclonal agents show promise but remain limited by lack of licensing and high costs, while bioagent therapies have not clearly demonstrated superior efficacy and safety over corticosteroids

• Insufficient data on emerging therapeutic approaches - Treatment studies for sarcoidosis-associated progressive pulmonary fibrosis have been underpowered to demonstrate clear benefits of anti-fibrotic agents, and further studies are needed to assess safety and efficacy of newer biologics

• Declining natural resolution rates in contemporary patient populations - Recent data shows resolution rates of only 17.9% at 2 years and 29.9% at 5 years, which are lower than historically reported, possibly due to aging populations and changing disease patterns

Beyond Pulmonary Sarcoidosis: Efzofitimod's Wider ILD Impact

Efzofitimod (PBI-4050) has been evaluated in clinical trials for Alström syndrome and idiopathic pulmonary fibrosis, expanding its therapeutic potential beyond pulmonary sarcoidosis. These studies employed different intervention models to assess safety and efficacy across diverse patient populations with fibrotic and metabolic conditions.

• Alström Syndrome Trial: A Phase 2, single-centre, single-arm, open-label study enrolled 18 patients with ALMS, administering PBI-4050 at 800 mg daily oral dose for an initial 24 weeks with continuation for an additional 36 or 48 weeks

• IPF Monotherapy and Combination Study: A 12-week open-label trial investigated PBI-4050 at 800 mg daily in patients with predominantly mild or moderate idiopathic pulmonary fibrosis, with 9 patients receiving PBI-4050 alone

• IPF Combination Therapy Arms: The same IPF study included combination therapy cohorts with 16 patients receiving PBI-4050 plus nintedanib and 16 patients receiving PBI-4050 plus pirfenidone to evaluate safety and pharmacokinetics

• Trial Design Rationale: The single-centre, single-arm, open-label design for Alström syndrome was specifically chosen to maximize subject exposure and increase likelihood of achieving study endpoints given the rarity and complexity of the disease

• Regulatory Registration: The Alström syndrome trial was registered on ClinicalTrials.gov (NCT02739217, February 2016) and European Union Drug Regulating Authorities Clinical Trials (EudraCT Number 2015-001625-16, September 2015)

Refining the Path for Efzofitimod in Pulmonary Sarcoidosis

Pulmonary sarcoidosis, a chronic inflammatory condition characterized by granuloma formation in the lungs, presents a significant challenge in clinical management. While corticosteroids remain the primary treatment, their long-term use is fraught with side effects, driving a critical need for effective, steroid-sparing alternatives. The recent announcement regarding efzofitimod's refined development path, following constructive FDA feedback, marks a pivotal moment for this investigational therapy.

Efzofitimod stands out due to its novel mechanism: it's a first-in-class biologic that selectively modulates neuropilin-2, a receptor highly expressed on immune cells within sarcoidosis granulomas. Early clinical data from a Phase 1b/2a study indicated that efzofitimod was well tolerated and showed dose-dependent improvements in patient-reported outcomes and a trend towards reduced corticosteroid use. Importantly, a post-hoc analysis revealed that therapeutic doses were associated with a lower relapse rate during steroid taper and an increase in forced vital capacity (FVC), suggesting a potential impact on lung function.

The decision to proceed with a new Phase 3 study, focusing on FVC as the primary endpoint and incorporating an increased dosing frequency, reflects a strategic move to robustly demonstrate efzofitimod's ability to improve lung function in patients with chronic, symptomatic pulmonary sarcoidosis with restrictive lung disease. This refined approach aims to address the core clinical manifestations of the disease more directly. However, the path forward is not without its considerations. The previous trial's primary analysis noted only a "nonsignificant trend" in lung function improvement, underscoring the need for the new Phase 3 to achieve clear statistical significance. Furthermore, the evolving therapeutic landscape, with established biologics and emerging targeted synthetic therapies, means efzofitimod will need to clearly differentiate itself. Successfully navigating these challenges could position efzofitimod as a valuable new option, offering patients a much-needed alternative to chronic corticosteroid reliance and potentially improving long-term outcomes and quality of life in this complex disease.