In short
This article discusses a clinical trial investigating the long-term use of Pabinafusp Alfa (JR-141) in male patients with Hunter Syndrome, also known as Mucopolysaccharidosis II (MPS II). The study aims to evaluate the drug's safety and effectiveness in treating both central nervous system (CNS) and somatic symptoms of this rare genetic disorder over an extended period.
At a glance
- Study Type
- Phase 3 extension study, open-label, no control, 2 cohorts
- Drug
- Pabinafusp Alfa (JR-141)
- Condition
- Mucopolysaccharidosis II (Hunter Syndrome)
- Primary Objectives
- Evaluate long-term efficacy on CNS symptoms and somatic symptoms, assess long-term safety
- Key Measurements
- CSF HS and DS concentrations, neuropsychological assessments, quality of life, liver and spleen volume, shoulder range of motion, six-minute walk test
- Duration
- Up to 4 years (Cohort A) or 5 years (Cohort B)
- Dosage
- 2.0 mg/kg, administered intravenously
- Key Eligibility
- Male patients who completed previous study (JR-141-GS31), no gene therapy treatment history
What is PABINAFUSP ALFA?
PABINAFUSP ALFA, also known by its product code JR-141, is a new medication being studied for the treatment of Hunter syndrome, a rare genetic disorder. It is classified as an orphan drug, which means it is specifically developed to treat a rare medical condition.
Medical Condition Treated
PABINAFUSP ALFA is designed to treat Mucopolysaccharidosis II, more commonly known as Hunter syndrome. This is a rare genetic disorder that primarily affects males. It is caused by a lack of an enzyme that breaks down certain complex molecules in the body, leading to a buildup of these molecules in various organs and tissues.
How PABINAFUSP ALFA Works
While the exact mechanism is not fully described in the provided information, PABINAFUSP ALFA is likely an enzyme replacement therapy. It's designed to replace or supplement the enzyme that is missing or deficient in people with Hunter syndrome. What makes this treatment unique is its potential ability to cross the blood-brain barrier, which could allow it to address both the body-wide (somatic) and brain (central nervous system or CNS) symptoms of the disease.
Clinical Trial Details
The clinical trial for PABINAFUSP ALFA is an extension study, which means it follows up on patients who participated in an earlier study. Here are some key details:
- It's a Phase 3 study, which is typically one of the final stages before a drug can be approved for general use.
- The study is open-label, meaning both the researchers and participants know which treatment is being given.
- There are two groups (cohorts) of participants:
- Cohort A: Participants start receiving PABINAFUSP ALFA from Week 105 of the previous study.
- Cohort B: Participants start receiving PABINAFUSP ALFA from Week 53 of the previous study.
- The study will continue for up to 4 years for Cohort A and 5 years for Cohort B, or until the drug receives marketing approval in the participant's country, whichever comes first.
Eligibility Criteria
To participate in this study, patients must meet certain criteria. Some key inclusion criteria are:
- Male patients who completed the previous study (JR-141-GS31) without safety concerns.
- Ability to provide informed consent (or have a legal representative provide consent).
- Agreement to use effective contraception if applicable.
Some reasons why a patient might not be eligible (exclusion criteria) include:
- Having received gene therapy treatment at any point.
- Being unable to undergo a lumbar puncture (a procedure where a needle is inserted into the lower back to collect spinal fluid).
- Having changed treatment from JR-141 to another drug (idursulfase) during the previous study.
- Having a history of serious drug allergies or sensitivity to components of JR-141.
Study Objectives
The main goals of this study are:
- To evaluate the long-term effectiveness of PABINAFUSP ALFA on CNS symptoms in patients with Hunter syndrome.
- To assess the long-term effectiveness of PABINAFUSP ALFA on somatic (body-wide) symptoms.
- To evaluate the long-term safety of PABINAFUSP ALFA in patients with Hunter syndrome.
Endpoints
The study will measure several outcomes (endpoints) to determine how well PABINAFUSP ALFA is working and how safe it is. Some of these include:
- Levels of certain substances (HS and DS) in the spinal fluid and blood.
- Neuropsychological assessments (tests of brain function).
- Quality of life assessments.
- Liver and spleen size.
- Shoulder range of motion.
- Six-minute walk test (to assess physical endurance).
- Pulmonary (lung) function tests.
- Safety assessments, including monitoring for side effects and checking various laboratory tests.
Administration and Dosage
PABINAFUSP ALFA is given as an intravenous injection, which means it's injected directly into a vein. The maximum daily dose is 2.0 mg/kg (milligrams per kilogram of body weight).
Safety Considerations
As with any medical treatment, there are potential risks and safety considerations:
- Patients will be monitored for adverse events (side effects) throughout the study.
- Regular laboratory tests, physical examinations, and other assessments will be conducted to ensure patient safety.
- Patients with a history of serious drug allergies or sensitivity to components of PABINAFUSP ALFA are not eligible for the study.
- The study will also monitor for infusion-associated reactions, which can occur when receiving medications through an IV.
It's important to note that this is an investigational treatment still being studied. While it shows promise, its full benefits and risks are still being evaluated. Patients and caregivers should discuss all potential treatment options with their healthcare providers.