FDA clears Phase 2 trial testing C5 inhibitor IM-101 in MG patients

Investigational therapy's effectiveness at easing symptoms to be evaluated

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by Andrea Lobo |

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The U.S. Food and Drug Administration (FDA) has cleared the launch of a Phase 2 clinical trial testing IM-101, ImmunAbs’ investigational therapy for myasthenia gravis (MG).

The multicenter, placebo-controlled trial is expected to enroll up to 90 people with MG who will receive IM-101 or a placebo once monthly. The trial will evaluate the treatment’s safety and effectiveness at easing MG symptoms.

“This … approval is pivotal for us as it brings us one step closer to delivering a transformative therapy for patients with autoimmune disorders,” Dongjo Kim, PhD, ImmunAbs’ CEO, said in a company press release. “We believe IM-101 has the potential to deliver deeper therapeutic responses and more durable remissions in patients who have failed to achieve sustained remission with current approved treatment.”

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IM-101 showed higher C5 inhibitory activity in preclinical studies

MG is an autoimmune disease characterized by muscle weakness and fatigue. It is caused by self-reactive antibodies that attack proteins involved in nerve-muscle communication and are needed to coordinate voluntary movements.

A growing body of evidence suggests that the activation of the complement system, a group of immune proteins that normally help defend the body against infections, also plays a role in driving MG.

Several complement inhibitor therapies that work to block complement activation have been approved to treat MG, such as Soliris (eculizumab), Ultomiris (ravulizumab-cwvz), and Zilbrysq (zilucoplan). All of them work by targeting a complement protein called C5. While existing C5 inhibitors have improved patient outcomes, some MG patients still experience residual disease activity due to incomplete complement inhibition, according to ImmunAbs.

IM-101 is a humanized antibody-based therapy that also targets the C5 protein and inhibits complement activation. In preclinical studies, it was found to have a higher C5 inhibitory activity compared with existing C5 antibody therapies.

A recently concluded Phase 1 clinical trial involving healthy volunteers who were given single-ascending doses of IM-101, or a placebo, demonstrated the treatment had a favorable safety profile and was well tolerated at all tested doses. No dose-limiting toxicity or severe adverse events were reported.

Additionally, IM-101 was shown to reduce C5 protein levels in the blood of the trial participants, supporting its efficacy in reducing the activity of the complement system in humans.