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Promising Trial News from argenx and Abcuro
The myositis community recently received encouraging news from two companies developing treatments for different forms of myositis. While much work remains before these therapies could potentially become available, recent clinical trial announcements from argenx and Abcuro offer renewed hope for patients and families affected by these rare and often disabling diseases.
argenx Reports Positive Results from the Phase 3 ALKIVIA Trial
This week, argenx announced positive topline results from its Phase 3 ALKIVIA clinical trial evaluating VYVGART Hytrulo (efgartigimod alfa and hyaluronidase-qvfc) in adults with autoimmune myositis, specifically immune-mediated necrotizing myopathy (IMNM) and dermatomyositis (DM). The study met its primary endpoint, demonstrating significant improvement in disease activity compared with placebo.
In the trial, participants receiving efgartigimod experienced a 15.4-point greater improvement in Total Improvement Score (TIS) after 52 weeks compared with those receiving placebo. Researchers also observed benefits as early as four weeks after treatment began, with improvements continuing throughout the year-long study.
One of the most notable findings came from patients with IMNM, a subtype for which there are currently no approved therapies. In this group, efgartigimod produced statistically significant improvements compared with placebo. Patients with dermatomyositis also showed clinically meaningful improvement, although the smaller size of that subgroup meant the results did not reach statistical significance.
Researchers reported that all six measures contributing to the Total Improvement Score favored efgartigimod. These measures included muscle strength, physical function, physician assessments, and other indicators of disease activity. In patients with dermatomyositis, improvements were also seen in skin disease activity. The treatment was generally well tolerated, and its safety profile was consistent with what has been observed in previous clinical studies of efgartigimod.
These results are important because they suggest that targeted treatment of the immune system may offer meaningful benefits beyond the broad immunosuppressive therapies that many patients currently rely on. Efgartigimod is already FDA-approved for generalized myasthenia gravis and CIDP. The positive ALKIVIA results may support future regulatory applications to expand its use to people with immune-mediated necrotizing myopathy and dermatomyositis.
Abcuro Advances Ulviprubart Development for Inclusion Body Myositis
While argenx’s news focused on autoimmune myositis, another important development is underway for people with inclusion body myositis (IBM). Abcuro recently announced plans to launch a new Phase 3 trial of ulviprubart (ABC008) after securing additional funding and discussions with the U.S. Food and Drug Administration regarding a path forward.
Earlier this year, Abcuro reported disappointing results from its Phase 2/3 MUSCLE study, which evaluated ulviprubart in 272 patients with IBM. The study did not achieve its primary endpoint in the overall patient population, nor did it meet key secondary endpoints.
However, in a pre-specified subgroup of patients with less severe disease, ulviprubart appeared to slow disease progression. Among patients who entered the study with higher IBM Functional Rating Scale (IBMFRS) scores, those receiving ulviprubart experienced approximately 50% slower functional decline compared with placebo over 76 weeks.
This observation has encouraged researchers and company leaders to continue development of the drug. The upcoming Phase 3 study is expected to focus on people with less advanced IBM, where the treatment appears most likely to potentially provide benefit.
Ulviprubart works differently from most other investigational therapies. It targets a protein called KLRG1 found on highly differentiated cytotoxic T cells. Researchers believe these immune cells may play an important role in the muscle damage seen in IBM. By selectively reducing these cells, ulviprubart aims to slow the disease process while preserving other important immune functions.
Importantly, the MUSCLE study found that ulviprubart had a favorable safety profile and was generally well tolerated compared with placebo. Nearly all participants who completed the study chose to continue into the open-label extension, allowing researchers to collect additional long-term safety and efficacy data.
Together, these developments highlight the remarkable progress being made in myositis research. While more research is needed, each clinical trial brings the community one step closer to safer, more effective therapies and, ultimately, better quality of life for people living with myositis.
