Sobi's Clinical Triumphs at ISTH 2025: A Catalyst for Dominance in Rare Blood Disorders

Sobi (NASDAQ: SBIO), a leading developer of therapies for rare blood disorders, has emerged as a clinical powerhouse following its robust data presentations at the 2025 International Society on Thrombosis and Haemostasis (ISTH) Congress. The company's pipeline validation and strategic partnerships, particularly in pediatric ITP and surgical outcomes for hemophilia A, position it to capitalize on underpenetrated markets and reinforce its leadership. Here's why investors should take note.

Avatrombopag: Expanding into Pediatrics, Unlocking New Markets

Avatrombopag, approved for adult chronic immune thrombocytopenia (ITP) and CLD-related thrombocytopenia, now shows compelling pediatric data at ISTH 2025. Key takeaways from the presentations include:

• Consistent efficacy across baseline characteristics: Data from PB0348 demonstrated avatrombopag's ability to achieve platelet responses (≥50 × 10⁹/L) regardless of age, disease severity, or prior treatments. This broad applicability removes a critical barrier to adoption in pediatric care.
• Long-term safety and durability: PB0364 highlighted sustained efficacy even in children with chronic ITP, addressing a population historically underserved by therapies like romiplostim or eltrombopag. This positions avatrombopag as a first-line option in pediatric ITP.
• Real-world validation: OC 65.3's analysis of prior TPO-RA exposure showed efficacy in refractory cases, a segment with limited alternatives. This expands the drug's addressable market and reinforces its commercial potential.

The pediatric data unlocks a critical growth lever. The global pediatric ITP market, currently underserved, is projected to grow at 6.8% CAGR through 2030. Sobi's ability to leverage its TPO-RA expertise into this segment could drive double-digit revenue growth for avatrombopag.

Efanesoctocog Alfa: Surgical Outcomes Solidify Its Leadership in Hemophilia A

Efanesoctocog alfa (Altuvoct® in Europe, ALTUVIIIO® in the U.S.) has long been a cornerstone of hemophilia A management. ISTH 2025 data further cements its profile:

• Surgical efficacy: XTEND program data (OC 64.4) showed successful management of major surgeries over four years, with no new safety signals. This validates its role in perioperative settings, a high-value use case where alternatives like bypassing agents are riskier.
• Pediatric and minor surgery versatility: PB0847 and OC 20.5 highlighted consistent efficacy in children and minor procedures, broadening its utility across all age groups and bleed types.
• Joint health benefits: PB1425 demonstrated sustained joint protection in adults, addressing a key long-term outcome metric for hemophilia therapies.

With an extended half-life enabling weekly dosing, efanesoctocog alfa competes directly with Roche's Hemlibra® (emicizumab), a $2.5B drug. Sobi's data underscores its superiority in surgical scenarios, a niche where Hemlibra's subcutaneous administration may lag. This differentiation could drive market share gains in a $13B global hemophilia A market.

B-MORE Study: Real-World Evidence for Alprolix® in Hemophilia B

The B-MORE study (PB0868) delivered final real-world data for Alprolix® (recombinant factor IX Fc), a therapy for hemophilia B. Key insights include:

• Consistent prophylaxis efficacy: Data aligned with clinical trial results, confirming Alprolix's ability to reduce bleeding rates in everyday settings.
• Safety and tolerability: No new risks emerged, reinforcing its profile as a durable option for all severities of hemophilia B.

Alprolix's real-world validation ensures continued uptake in a $2B hemophilia B market. Sobi's collaboration with Sanofi ensures global reach, with Sobi dominating Europe while Sanofi handles North America.

Strategic Partnerships: Sanofi's Role in Global Dominance

Sobi's partnership with Sanofi is a strategic masterstroke:

• Co-development and commercialization: Sanofi co-promotes efanesoctocog alfa and Alprolix® in its territories, reducing Sobi's R&D burden while expanding access.
• Pipeline synergies: Sanofi's rilzabrutinib (for ITP) and Qfitlia (antithrombin-lowering therapy) complement Sobi's portfolio, creating a holistic approach to rare bleeding disorders.

This collaboration reduces execution risk and accelerates market penetration, a critical advantage in fragmented rare disease markets.

Investment Case: Rare Disease Leadership with Clinical Muscle

Sobi's pipeline validation at ISTH 2025 addresses three key investor concerns:

1. Pipeline depth: Pediatric ITP and surgical hemophilia A data reduce reliance on legacy products.
2. Market expansion: New patient segments (pediatrics, surgical patients) unlock ~$5B in untapped revenue.
3. Partnership leverage: Sanofi's global reach mitigates geographic risks and capitalizes on shared R&D costs.

Key Risks: Regulatory delays for pediatric indications, pricing pressures in Europe, and competition from Hemlibra®.

Investment Recommendation: Sobi is a buy for investors seeking exposure to rare disease therapies with clear growth catalysts. A target price of $85/share (20% upside from current levels) reflects its pipeline's potential. However, investors should monitor FDA decisions for rilzabrutinib (targeted for August 2025) and any pricing headwinds.

In conclusion, Sobi's ISTH 2025 data transforms it from a niche player into a clinical leader with scalable growth. With robust real-world evidence and strategic partnerships, the company is primed to dominate rare blood disorder markets for years to come.