MDA 2026: Insmed launches Phase 1 trial of INS1202 gene therapy for ALS
First-in-human study will test therapy in people with or without SOD1 mutations
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- Insmed has launched a Phase 1 clinical trial testing INS1202, an experimental gene therapy for ALS.
- INS1202 is designed to reduce levels of the toxic SOD1 protein implicated in some ALS cases, including sporadic disease.
- The ARMOR trial will evaluate the therapy’s safety, tolerability, and biological activity in adults with ALS.
Insmed has launched a first-in-human clinical trial evaluating its experimental gene therapy INS1202 in people with amyotrophic lateral sclerosis (ALS).
The Phase 1 study, called ARMOR (NCT07290062), aims to enroll about 23 adults with ALS, ages 18 to 80, who have been living with the disease for less than 3.5 years. The trial is currently recruiting participants at a site in Missouri.
Mark Stahl, MD, PhD, Insmed’s executive director of clinical development, presented the study’s design this week at the Muscular Dystrophy Association (MDA) Clinical & Scientific Conference 2026 in Orlando, Florida. The work was described in a poster titled, “A First-in-Human Dose-Escalation Study of Intrathecal INS1202 Gene Therapy in Adults with Amyotrophic Lateral Sclerosis (ALS).”
SOD1 mutations linked to some ALS cases
In ALS, the nerve cells that control movement, called motor neurons, gradually become damaged and die. While most people with ALS have no known disease-causing mutations, about 10%-20% of familial ALS cases and roughly 1%-2% of sporadic cases involve mutations in the SOD1 gene.
These mutations lead to production of an abnormal SOD1 protein that can form toxic clumps inside nerve cells. But abnormal SOD1 protein clumps have also been found in “a rather substantial portion” of patients with no known mutations, according to Stahl.
Stahl noted that this affects not only nerve cells but also glia, which support and protect nerve cells in the brain and spinal cord.
“Over the last 30 plus years, we really have come to understand the toxic gain of function that is seen in patients who have SOD1 mutations in ALS and … in the last maybe six to 10 years or so, additional work has identified similar confirmations of SOD1 proteins in the [spinal fluid] and in the neural and glial tissue of some [patients without ALS-causing mutations],” Stahl said.
INS1202 designed to reduce SOD1 protein levels
INS1202 is an experimental gene therapy designed to deliver a short piece of genetic material known as short-hairpin RNA into cells. This molecule binds to the SOD1 messenger RNA, the template used to produce the SOD1 protein, and targets it for degradation, which may reduce levels of the protein.
INS1202 uses an adeno-associated virus serotype 9 (AAV9) to deliver its genetic payload into cells. This type of viral vector is widely used in gene therapies for neurological disorders because it can efficiently deliver genes to nerve and glial cells while generally not causing illness in people.
Stahl said INS1202 has shown encouraging effects in preclinical studies. In mice carrying SOD1 mutations, treatment with INS1202 improved motor neuron survival and motor function, and improved survival outcomes to an extent “nearly unheard of with this model,” Stahl said.
Researchers also evaluated INS1202 in a model where skin cells are taken from ALS patients and converted into glia, which can then be grown alongside healthy motor neurons. In these experiments, glia from ALS patients with SOD1 mutations or without any ALS-causing mutations caused the motor neurons to sicken and die. However, INS1202 treatment reversed this effect in samples from 7 out of 10 patients tested.
“This is another piece of data that really helped us understand that” reducing SOD1 levels may improve disease features in “at least a proportion of sporadic ALS patients,” Stahl said.
The Phase 1 ARMOR trial is open to adults with ALS who either carry SOD1 mutations or have sporadic disease without known ALS-causing mutations. Participants will receive oral steroids alongside the gene therapy to help prevent immune reactions, meaning the study is limited to people who can swallow oral medications. Participants may continue receiving their standard ALS therapies while enrolled.
Participants will receive a single dose of INS1202 at one of three planned dose levels. Dose escalation includes a 30-day safety monitoring period between early participants and between dosing groups. The study’s main goal is to evaluate safety and tolerability over about one year of follow-up, with longer-term safety monitored in a four-year extension study.
ARMOR trial will assess safety and dosing
One key secondary goal of the study is to identify an appropriate dose for future clinical testing of INS1202. The trial will also assess other outcomes, including how treatment affects measures of motor function, biomarkers linked to nerve damage, and patient-reported outcomes.
Researchers will also collect skin samples to conduct the glia-based assay described earlier, Stahl said.
“ARMOR will enhance understanding of the safety and tolerability of INS1202, and provide proof-of-principle of its biological activity in patients with ALS, informing the dose selection and patient populations for future studies,” the researchers wrote in a poster describing the trial.
Because ARMOR is testing this SOD1-targeting therapy in people with SOD1 mutations as well as individuals without known mutations, Stahl said the study will “help to address this underlying question of the role of SOD1 in sporadic ALS, which I think is just another part of the excitement of this study.”
Note: The ALS News Today team is providing live coverage of the 2026 MDA Clinical & Scientific Conference March 8-11 in Orlando, Florida. Go here to see the latest stories from the conference.
