Summary of Argenx Update / Briefing on September 16, 2025 Company Overview - **Company**: Argenx (NasdaqGS: ARGX) - **Focus**: Development of argenx 119, a Musk agonist targeting neuromuscular junction diseases Key Points and Arguments Industry and Product Development - Argenx is spotlighting argenx 119, which is moving into a registrational study for Congenital Myasthenic Syndromes (CMS) after a GO decision in June 2025 [2][4] - The company aims to be involved in 50,000 patients across all medicines by 2030, with 10 labeled indications and 5 new late-stage studies [4] - Argenx 119 is part of a broader vision to bring transformational biology to patients, with a focus on foundational components of the immune system [5][6] Clinical Trials and Data - Argenx 119 is currently in phase 3 trials for CMS, Amyotrophic Lateral Sclerosis (ALS), and Spinal Muscular Atrophy (SMA) [5][8] - The company has a data-rich approach to developing treatments for CMS, utilizing digital sensors to gather real-world data from patients [10][68] - A phase 1B study enrolled 16 patients with CMS, showing a favorable safety profile and proof of biology, leading to plans for a registrational study [72][80] Mechanism of Action - Argenx 119 targets muscle-specific kinase (MuSK), which is crucial for the formation and maintenance of neuromuscular junctions [17][20] - The drug promotes MuSK activation, leading to clustering of acetylcholine receptors, which is essential for muscle contraction [17][20] - The mechanism is particularly relevant for patients with congenital myasthenic syndromes caused by mutations affecting neuromuscular junction proteins [21][22] Collaboration and Innovation - The development of argenx 119 involved collaboration with key opinion leaders and researchers, emphasizing the importance of partnerships in advancing drug development [6][19] - The Immunology Innovation Program (IIP) has been instrumental in sourcing novel biology and driving transformational outcomes [6][7] Patient Impact and Testimonials - The briefing included a patient testimonial highlighting the severe impact of CMS and the lack of effective treatments, underscoring the urgency of developing argenx 119 [63][66] - The company aims to empower patients and improve their quality of life through innovative treatments [68][81] Future Directions - Argenx is exploring additional indications for argenx 119 beyond CMS, including ALS, where there are currently no effective treatments available [58][59] - The company plans to continue leveraging data from ongoing studies to refine treatment approaches and enhance patient outcomes [70][80] Additional Important Content - The neuromuscular junction's biology and the role of various proteins, including Agrin, LRP4, and DOK7, were discussed, emphasizing the complexity of neuromuscular diseases [12][13][16] - The collaboration between academic researchers and Argenx has led to significant advancements in understanding neuromuscular junction biology and developing targeted therapies [44][46] This summary encapsulates the key points from the Argenx briefing, focusing on the company's strategic direction, product development, clinical trial outcomes, and the broader implications for patients suffering from neuromuscular diseases.

Financial Data and Key Metrics Changes - The company is experiencing significant growth in the FcRn space, with a focus on expanding its pipeline and product offerings [5][6] - The launch of the prefilled syringe (PFS) in April has been a key growth driver, expanding both the patient and prescriber populations [17][19] - The company reported that over 50% of patients using Vivgart live a life without symptoms, highlighting the drug's efficacy and safety profile [21] Business Line Data and Key Metrics Changes - The company has successfully launched Vivgart in two indications: Myasthenia Gravis (MG) and Immune Thrombocytopenia (ITP), with ongoing expansion into additional indications [5][30] - The PFS has attracted 1,150 prescribers, with 150 being new to Vivgart, indicating a successful expansion into the community [18][20] - The total addressable market (TAM) for MG is projected to be 60,000 patients, with ongoing efforts to expand the label to include seronegative and ocular myasthenia [30][40] Market Data and Key Metrics Changes - The FcRn class currently holds around 10% of the market share for novel biologics in MG, with expectations for significant growth as awareness and adoption increase [27][28] - Japan is identified as a key market, showing impressive growth, particularly following the launch of CIDP [40][41] - The company is focused on disciplined pricing strategies to ensure value proposition while navigating the complexities of pricing and reimbursement in Europe and Canada [42] Company Strategy and Development Direction - The company aims to build a leadership position in the FcRn space by investing in next-generation molecules and expanding its product offerings [69][70] - The strategy includes a focus on patient education to drive demand and adoption of Vivgart, particularly among physicians who may be resistant to change [35][36] - The company is committed to expanding its pipeline beyond Vivgart, with multiple ongoing Phase III trials and a focus on innovative therapies for various indications [56][78] Management's Comments on Operating Environment and Future Outlook - Management expressed confidence in the growth potential of the FcRn space, citing historical patterns of market expansion driven by innovation [24][25] - The company acknowledges the challenges of inertia among physicians but emphasizes the importance of patient advocacy in driving change [35][36] - Future data readouts from ongoing trials are expected to significantly enhance the company's growth trajectory and market presence [56][58] Other Important Information - The company is developing multiple presentations of Vivgart, including auto-injectors and hyper-concentrated formulations, to enhance patient experience [72][73] - The upcoming R&D event is expected to showcase advancements in the neuromuscular junction space, highlighting the company's commitment to innovation [82] Q&A Session Summary Question: How has the opportunity set evolved with Vivgart? - Management discussed the initial beachhead strategy and the expansion into multiple indications, emphasizing the growing pipeline and market potential [5][6] Question: How does the PFS fit into the overall strategy? - The PFS is seen as a key growth driver, providing independence to patients and expanding the prescriber base [17][19] Question: What are the competitive dynamics in the MG market? - Management noted that the MG space is becoming increasingly competitive, but innovation is expected to grow the overall market rather than just share among existing players [24][25] Question: What is the outlook for CIDP? - The company is optimistic about CIDP, expecting to build on initial experiences and expand usage beyond refractory patients [44][45] Question: What are the expectations for upcoming Phase III trials? - Management anticipates significant data readouts in the coming year, which could transform the therapeutic landscape for several indications [56][58]