Dianthus Therapeutics Advances gMG Treatment with Promising Phase 2 Results

Dianthus Therapeutics has made significant strides in the competitive generalized myasthenia gravis (gMG) market, announcing positive results from its phase 2 trial of claseprubart. The company is now gearing up for a pivotal phase 3 study, positioning itself as a potential challenger to established treatments in the autoimmune disease space.

Phase 2 Trial Results Show Efficacy and Tolerability

The phase 2 trial evaluated two doses of claseprubart, an antibody engineered to selectively target the classical pathway, against placebo in 65 adults with AChR-positive gMG. Patients received subcutaneous injections every two weeks, with the primary endpoint focusing on safety and tolerability.

Secondary endpoint data provided insights into the drug's efficacy:

• Low dose: 4.6-point improvement on MG-ADL scale (1.8 points placebo-adjusted)
• High dose: 5.4-point improvement on MG-ADL scale (2.6 points placebo-adjusted)
• QMG scores improved by 4.4 and 4.5 points for low and high doses, respectively

The company reported that claseprubart was generally well-tolerated, setting the stage for further development.

Strategic Positioning in a Competitive Market

Dianthus is positioning claseprubart as a potential best-in-class treatment for gMG, aiming to combine the efficacy of C5 inhibitors with the safety of C1 blockers and the convenience of more user-friendly administration methods.

Key differentiators include:

1. Dosing frequency: Plans to test both two-week and four-week dosing regimens in phase 3
2. Administration method: Development of an autoinjector for improved patient convenience
3. Market opportunity: Targeting the >80% of AChR-positive gMG patients not yet on biologic treatments

CEO Marino Garcia emphasized the potential for further differentiation, stating, "Why not go further? Why not push that differentiation? I don't see much of a downside to be honest."

Looking Ahead to Phase 3

Based on the phase 2 results, Dianthus is preparing for a phase 3 trial with the following considerations:

• Focus on the low dose, which showed comparable efficacy to the high dose
• Exploration of both two-week and four-week dosing schedules
• Continued development of the autoinjector for improved administration

As Dianthus moves forward, the company aims to address current limitations in gMG treatment, such as intravenous administration and high-volume subcutaneous dosing, which have been identified as barriers to uptake of existing therapies.