RGX-121 Gene Therapy for Hunter Syndrome

No longer recruiting at 2 trial locations

Overseen By Patient Advocacy

Age: < 18

Sex: Male

Trial Phase: Phase 1 & 2

Sponsor: REGENXBIO, Inc.

Must not be taking: AAV-based gene therapy

Disqualifiers: Neurocognitive deficit, Neuropsychiatric condition, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 40

Duration: 1 day

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores a gene therapy treatment for children with severe Hunter Syndrome, a rare genetic disorder affecting mental and physical development. The study aims to determine if this new therapy is safe and can improve symptoms by delivering a healthy gene to the brain. Children diagnosed with Hunter Syndrome who show specific signs of cognitive decline or have a family history of a severe form of the condition might be suitable candidates for this trial. As a Phase 1/Phase 2 trial, this research focuses on understanding how the treatment works and measuring its effectiveness in an initial, smaller group of participants, offering them a chance to contribute to groundbreaking advancements in therapy.

Do I have to stop taking my current medications for the trial?

If you are receiving ELAPRASE® via intrathecal (IT) administration, you must stop taking it for the duration of the study. The protocol does not specify other medication restrictions, so it's best to discuss your current medications with the study team.

Is there any evidence suggesting that RGX-121 is likely to be safe for humans?

Research has shown that RGX-121, a gene therapy for Hunter syndrome, is generally safe and well-tolerated. In earlier studies, RGX-121 produced positive results over a 12-month period. These studies found that patients handled the treatment well, and it improved their condition.

Another study focused on safety and effectiveness confirmed that RGX-121 is well-tolerated by patients with Hunter syndrome. This is promising because it suggests the treatment does not cause serious side effects.

Since RGX-121 is in the early stages of clinical trials, reaching this phase indicates some evidence of safety and tolerability. More information from ongoing trials will provide a clearer picture, but current findings are encouraging for those considering participation. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising?

RGX-121 is unique because it offers a gene therapy approach for treating Hunter Syndrome, a rare genetic disorder. Unlike current treatments that mainly manage symptoms, RGX-121 aims to address the root cause by delivering a healthy copy of the defective gene directly to the brain. This innovative delivery method could potentially halt or even reverse disease progression, which is why researchers are so hopeful about its potential impact.

What evidence suggests that RGX-121 might be an effective treatment for Hunter Syndrome?

Research has shown that RGX-121 gene therapy, which participants in this trial will receive, may help treat Hunter Syndrome (MPS II). In one study, patients experienced about an 85% reduction in harmful substances in their spinal fluid, indicating that the treatment worked in the brain and central nervous system. Another study found that patients improved just 12 months after a single treatment. These results suggest that RGX-121 can help manage symptoms and possibly enhance the quality of life for people with MPS II. ^{1 2 5 6 7}

Are You a Good Fit for This Trial?

This trial is for children over 5 with severe Hunter Syndrome, showing specific neurocognitive decline. They must have a genetic diagnosis of MPS II and not be responding to standard treatments. Kids can't join if they've had gene therapy before, are allergic to certain enzyme treatments, or have immune system issues that prevent them from taking immunosuppressants.

Inclusion Criteria

A family member has neuronopathic MPS II with the same mutation as mine, and a geneticist confirms I have inherited it.

I have MPS II and my neurocognitive test scores are below average.

I have MPS II and my brain function tests show a decline over time.

Exclusion Criteria

I cannot take immunosuppressive medications due to health reasons.

My body is not responding to ELAPRASE® due to certain antibodies.

I agree to stop my ELAPRASE® treatment via spinal injection for the study.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive a single dose of RGX-121 administered by IC or ICV injection

1 day

1 visit (in-person)

Primary Study Period

Safety is the primary focus for the initial 24 weeks after treatment

24 weeks

Visits at Week 1, Week 2, Week 4, Week 12, Week 24

Follow-up

Participants are monitored for safety and efficacy for up to a total of 104 weeks following treatment

80 weeks

Visits at Week 38, Week 52, Week 64, Week 78, Week 104

What Are the Treatments Tested in This Trial?

Interventions

• RGX-121

Trial Overview The study tests RGX-121 gene therapy aimed at delivering a working IDS gene to the brain. It's in early stages (phase I/II) to see if it's safe and might work for kids with neuronopathic Hunter Syndrome who haven't improved on current therapies.

How Is the Trial Designed?

Group I: Single Arm Experimental Treatment 1 Intervention

6.5 × 10\^10 GC/g brain mass of RGX-121

Who Is Running the Clinical Trial?

REGENXBIO, Inc.

Lead Sponsor

Trials

20

Recruited

2,800+

Regenxbio Inc.

Lead Sponsor

Trials

20

Recruited

2,800+

REGENXBIO Inc.

Lead Sponsor

Trials

25

Recruited

3,100+

Citations

1. ir.regenxbio.com ir.regenxbio.com/news-releases/news-release-details/regenxbio-presents-positive-twelve-month-pivotal-data-phase

REGENXBIO Presents Positive Twelve-Month Pivotal Data ... 12-month pivotal data further demonstrate the ability of one-time RGX-121 treatment to improve outcomes for patients with MPS II.

2. clinicaltrials.gov clinicaltrials.gov/study/NCT03566043

NCT03566043 | CAMPSIITE™ RGX-121 Gene Therapy in ... This study is a safety and efficacy, dose ranging study to determine whether RGX-121 is safe, effective and well-tolerated by patients with MPS II. Detailed ...

3. prnewswire.com prnewswire.com/news-releases/regenxbio-presents-positive-twelve-month-pivotal-data-from-phase-iiiiii-campsiite-trial-of-rgx-121-for-treatment-of-mps-ii-302547381.html

REGENXBIO Presents Positive Twelve-Month Pivotal Data ... 12-month pivotal data further demonstrate the ability of one-time RGX-121 treatment to improve outcomes for patients with MPS II.

4. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10875268/

Comparative dose effectiveness of intravenous and intrathecal ... AAV.CB7.hIDS (RGX-121) prevented neurologic and skeletal manifestations of murine mucopolysaccharidosis type II after either intravenous or intrathecal ...

5. cgtlive.com cgtlive.com/view/regenxbio-mpsii-gene-therapy-rgx-121-continues-efficacy-long-term-trial-data

REGENXBIO's MPSII Gene Therapy RGX-121 Continues to ... Among patients who received the pivotal dose level, a median reduction of 85% in HS D2S6 levels was seen in the CSF.

6. regenxbio.gcs-web.com regenxbio.gcs-web.com/news-releases/news-release-details/regenxbio-announces-fda-review-extension-bla-rgx-121-treat

REGENXBIO Announces FDA Review Extension of BLA for ... RGX-121 is a potential one-time AAV therapeutic for the treatment of boys with MPS II, designed to deliver the iduronate-2-sulfatase (IDS) gene ...

7. neurology.org neurology.org/doi/10.1212/WNL.96.15_supplement.4164

RGX-121 gene therapy for severe Mucopolysaccharidosis ... MPS II or Hunter syndrome is caused by a deficiency of iduronate-2-sulfatase (I2S) leading to an accumulation of glycosaminoglycans (GAG) in ...