Experimental MS treatment IMP761 found safe, well tolerated in Phase 1 trial
Healthy volunteers received single increasing doses of immunotherapy
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A nurse prepares to draw a man's blood for testing. (Photo by iStock)
- Experimental multiple sclerosis (MS) treatment IMP761 was safe and well-tolerated in a Phase 1 trial.
- IMP761 dampens overactive T-cells by activating LAG-3, showing immunosuppressive effects.
- A Phase 2 trial is planned to determine optimal dosing for MS and other autoimmune diseases.
IMP761, an experimental immunosuppressive therapy being developed by Immutep for multiple sclerosis (MS) and other autoimmune diseases, was well tolerated in healthy volunteers when given at single increasing doses.
The findings come from the single-ascending dose portion of an ongoing Phase 1 clinical trial (NCT06637865), which tested IMP761 when administered intravenously (into the vein) at doses up to 14 mg/kg. No safety concerns or dose-limiting toxicities have been reported to date.
The first-in-human trial is now moving into its next stage, in which participants will receive three infusions of IMP761 at two different dose levels or a placebo. That part is expected to be completed by the end of September.
Early data also suggest the therapy is having its intended biological effect — dampening the activity of T-cells, immune cells that drive inflammation in MS and other autoimmune diseases.
“IMP761 continues to show a clear immunosuppressive effect in healthy participants …, with durable inhibition of T-cell-mediated responses after a single administration,” Frédéric Triebel, Immutep’s chief scientific officer, said in a company press release.
IMP761 may have potential to treat rheumatoid arthritis, type 1 diabetes
MS is an autoimmune disease in which the immune system mistakenly attacks healthy tissue in the brain and spinal cord. While many immune cells are involved in this attack, T-cells are known to become overactive and play a key role in MS and several other autoimmune conditions.
IMP761 is an antibody-based therapy designed to activate LAG-3, a protein receptor found on the surface of activated T-cells. Because LAG-3 acts as a natural brake on the immune system, activating it is expected to reduce harmful T-cell activity and help prevent attacks on a patient’s own tissues.
The Phase 1 trial is being conducted at a single site in the Netherlands to evaluate the safety and pharmacological properties of IMP761, including how it behaves in the body.
These first-in-human findings support our mechanistic aim of selectively silencing [self-reactive] T cells … and provide the basis for dose levels to be tested in a future phase II trial in patients with autoimmunity.
It includes three parts. In parts A and B, a total of 65 participants received a single dose of IMP761 or a placebo across eight escalating dose groups. Participants in part B were also given an injection of keyhole limpet hemocyanin, a protein used to trigger a controlled immune response in the skin. This allows researchers to assess how effectively IMP761 can suppress this immune response.
Part C is now expected to enroll 14 additional participants to test multiple doses of IMP761 at two dose levels. Participants will receive three infusions, administered 28 days apart, to identify the optimal dose for a future Phase 2 trial.
“These first-in-human findings support our mechanistic aim of selectively silencing [self-reactive] T cells … and provide the basis for dose levels to be tested in a future phase II trial in patients with autoimmunity,” Triebel said.
Beyond MS, the therapy may have the potential to treat several other autoimmune diseases, including rheumatoid arthritis and type 1 diabetes.
