Phase 2 Trial of ARGX-113, a Potential Therapy for MG, Is Still Enrolling Patients

ARGX-113, an investigational therapy for myasthenia gravis (MG), is progressing in a Phase 2 clinical trial (NCT02965573) that is still enrolling patients, according to the biotech company argenx in its quarterly update.

MG is an autoimmune disorder, mostly characterized by abnormal responses of the patients’ own T-cells (a type of immune cell) and antibodies against proteins located in the neuromuscular junction (the connection between a motor neuron and a muscle fiber). This mechanism leads to the fatigue and weakness observed in MG.

Aiming to address this unmet medical need, argenx is developing ARGX-113, an antibody fragment designed for diseases associated with high levels of immunoglobulin G (IgG), the most common type of antibody in human circulation.

ARGX-113’s mode of action includes blocking IgG recycling into the bloodstream and increasing its clearance, which may result in faster disease remission and decreased duration and severity of acute crises.

The product holds therapeutic potential in several disorders beyond MG, including immune thrombocytopenia (ITP, a bleeding disorder caused by low numbers of platelets), multiple sclerosis, and systemic lupus erythematosus (SLE).

The Phase 2 MG trial aims to determine the safety, effectiveness and pharmacological profile (how the drug is processed in the body) of ARGX-113 in patients who have generalized muscle weakness. The company announced that it reached half of its enrollment goal of 24 patients.

Among the outcome measures that argenx will study are changes in incidence and severity of adverse effects of ARGX-113, alterations in vital signs, laboratory assessments, and electrocardiogram results, and changes in MG activity and patients’ quality of life.

The product had previously shown a favorable safety profile, and effective and sustained reduction of IgG levels of up to 85 percent in prior studies testing both single and multiple doses.

“The first half of 2017 has been a period of momentous growth for argenx,” Tim Van Hauwermeiren, the company’s CEO, said in a press release. Van Hauwermeiren said this enables argenx to proceed with the development of ARGX-113. Full results from the Phase 2 study in MG are expected in 2018.

The company will also test subcutaneous dosing of ARGX-113 in a Phase 1 study with healthy volunteers, expected to start in the second half of 2017. Also, data from a Phase 2 trial of ARGX-113 on ITP (NCT02965573) is expected in the second half of 2018. This study in ITP is also still recruiting participants.