juMPStart, a clinical trial for adults with MPS II,
also known as Hunter syndrome
See If You Pre-Qualify

About juMPStart

The juMPStart study is investigating the safety and efficacy of an investigational one-time gene therapy, HMI-203 in adult patients with mucopolysaccharidosis type II (MPS II), also known as Hunter syndrome. In Hunter syndrome, the iduronate-2-sulfatase (IDS) gene is missing or malfunctioning, and the body is unable to produce the iduronate-2-sulfatase (I2S) enzyme that breaks down glycosaminoglycans (GAGs), large sugar molecules or cellular waste. The resulting accumulation of GAGs in patients with MPS II causes symptoms such as joint stiffness, carpal tunnel syndrome, sleep apnea and loss of hearing.

Currently, there are no available treatments targeting the genetic cause of MPS II; standard of care treatments only address the symptoms. HMI-203 is an investigational gene therapy designed to deliver the IDS gene with a one-time intravenous (I.V.) infusion.

In the juMPStart study, investigational HMI-203 is designed to deliver functional copies of IDS gene throughout the body, including to peripheral organs and the central nervous system, using an adeno-associated virus (AAV). Participation in this clinical trial may include enzyme replacement therapy (ERT) discontinuation.

You may be eligible to participate in the juMPStart study if you:

  • Are a male between the ages of 18-45 years
  • Have a confirmed diagnosis of MPS II
  • Are currently receiving ERT as treatment for MPS II

Additional eligibility criteria will apply.

juMPStart Participation Overview

The juMPStart study is an open-label, Phase I dose-escalation study designed to evaluate three doses of the study drug, HMI-203. The trial is designed to enroll 9 participants with MPS II. All participants who are eligible and successfully enroll will receive the investigational gene therapy; there will be no placebo group in this study.

Study participants will receive a single I.V. infusion of HMI-203 and study-related care at no cost. Each participant will be observed for 52 weeks and then seen less frequently for an additional 4 years. Home health visits will be offered, as applicable. In addition, if you are considering participating in this study, all travel related expenses will be reimbursed (including overnight lodging, if required).

About juMPStart study

Refer a Friend

Do you know someone between the ages of 18-45 who has MPS II/Hunter Syndrome? They may be eligible to participate in the juMPStart study. Consider sharing information with them about how they can learn more.