In their recently published Q4 2025 investor letter, the Artisan Mid Cap Fund reaffirmed its enduring confidence in Argenx SE (NASDAQ:ARGX), a prominent commercial-stage biopharmaceutical firm. This steadfast belief is primarily anchored in the remarkable performance of Argenx’s groundbreaking autoimmune treatment, VYVGART®. Despite facing a setback with the discontinuation of a mid-stage trial for thyroid eye disease, the fund underscores the drug's impressive sales trajectory and its potential across numerous other indications currently under investigation. Argenx’s strong market capitalization and significant growth over the past year position it as a key driver for the fund's overall performance.
Artisan Mid Cap Fund's Continued Commitment to Argenx SE and VYVGART®
On Tuesday, February 24, 2026, Soumya Eswaran reported on the Artisan Mid Cap Fund's Q4 2025 investor letter, highlighting their sustained conviction in Argenx SE (NASDAQ:ARGX). This biopharmaceutical company, specializing in commercial-stage drug development, has been a leading contributor to the fund's strong quarterly results. Argenx's flagship product, VYVGART®, an innovative therapy for autoimmune conditions like myasthenia gravis and chronic inflammatory demyelinating polyradiculoneuropathy, has seen remarkable success. The latest earnings report revealed a near-doubling of VYVGART® sales year-over-year, reaching an impressive annualized figure exceeding $4 billion. This surge was significantly bolstered by a notable increase in new patient adoption, further propelled by the launch of a convenient prefilled syringe formulation.
However, the company did encounter a challenge late in the fourth quarter when a mid-stage clinical trial for thyroid eye disease was halted due to a lack of efficacy. This development led to a slight dip in the stock's performance for the quarter. Nevertheless, the Artisan Mid Cap Fund views this as a minor impediment, maintaining its optimistic outlook on VYVGART®'s broader potential. The drug is currently being evaluated for more than a dozen other diseases, presenting substantial opportunities for future growth and market expansion. As of February 23, 2026, Argenx SE (NASDAQ:ARGX) shares closed at $826.25, reflecting a one-month return of -0.83% but an impressive 31.96% gain over the preceding 52 weeks. The company commands a substantial market capitalization of $51.131 billion, underscoring its significant presence and influence in the biopharmaceutical sector.
Insights and Future Outlook
The Artisan Mid Cap Fund's unwavering support for Argenx SE, particularly in the face of clinical trial volatility, underscores a crucial principle in long-term investing: focusing on core strengths and broader pipeline potential rather than short-term setbacks. The robust sales performance of VYVGART® demonstrates the significant unmet medical need it addresses and its strong market acceptance. While the discontinuation of the thyroid eye disease trial is regrettable, it highlights the inherent risks in drug development and the importance of diversified research. The ongoing investigation of VYVGART® for numerous other indications suggests a promising future for Argenx, potentially unlocking new revenue streams and solidifying its position as a leader in autoimmune disease therapy. This case reinforces the idea that strategic investments in innovative biopharma companies with strong product foundations can yield substantial returns, even amidst the inevitable ups and downs of clinical research and development.