at Oakland, California and other locations
study started
completion around
Principal Investigator
by Paul Harmatz
Headshot of Paul Harmatz
Paul Harmatz



Phase I/II, open label, multicenter, multinational (Japan, Brazil and the US) extension study of JR-171-101 for the treatment of MPS I

Official Title

An Extension Study of JR-171-101 Study in Patients With Mucopolysaccharidosis Type I


Patients who have completed the Part2 of JR-171-101 study and fulfill all eligibility criteria can be enrolled in this JR-171-102 study. Until the dose determination in the JR-171-102 study, subjects will intravenously receive either low dose or high dose of JR-171 at the same doses received at Week 12 of the JR-171-101 study. Thereafter, all subjects will be transitioned to the optimal dose determined based on the results of JR-171-101 study.


Mucopolysaccharidosis I, Mucopolysaccharidoses, JR-171 (lepunafusp alfa)


You can join if…

  • Patients who have completed the Part 2 of JR-171-101 study
  • A patient from whom written informed consent can be obtained. If the patient is aged under 18 years (20 years in case of Japan) at the time of assent or willingness to participate in the study cannot be confirmed due to MPS I-related intellectual disability, informed permission from the patient's legally acceptable representative (e.g., his/her parents or guardians) need to be obtained instead of his/her consent. Even in this case, written informed consent should be obtained from the patient, wherever possible
  • Female patient or male patient whose co-partners is of child-bearing potential agree to use a medically accepted, highly effective method of contraception, such as spermatocidal gel plus condom, an intrauterine device or oral contraceptives until one month after the final administration.

You CAN'T join if...

  • A patient who is unable to perform the study procedures, except for 6-minute walk test, neurocognitive testing, BVMT-R, HVLT-R, and T.O.V.A.
  • Judged by the principal investigator or subinvestigator as being unable to undergo lumbar puncture, including those who have difficulties in taking a position for lumbar puncture due to joint contracture or those who are likely to experience difficulty breathing during the lumbar puncture process
  • Judged by the principal investigator or subinvestigator to be ineligible to participate in the study due to a history of a serious drug allergy or hypersensitivity to any drugs
  • Otherwise judged by the principal investigator or subinvestigator to be ineligible to participate in the study in consideration of patient's safety


  • UCSF Benioff Children's Hospital Oakland
    Oakland California 94609 United States
  • Fukuoka Children's Hospital
    Fukuoka Japan
  • National Hospital Organization Kokura Medical Center
    Kitakyushu Japan
  • Osaka Metropolitan University Hospital
    Osaka Japan

Lead Scientist at UCSF

  • Paul Harmatz
    Dr. Paul Harmatz is a gastroenterologist who specializes in mucopolysaccharidoses (MPS) and other lysosomal storage diseases (genetic disorders in which a lack of certain enzymes results in progressive damage to cells and organ systems). He leads a team of specialists who diagnose and care for patients with these rare diseases, offering therapies such as weekly enzyme infusion.


in progress, not accepting new patients
Start Date
Completion Date
JCR Pharmaceuticals Co., Ltd.
Phase 1/2 research study
Study Type
About 14 people participating
Last Updated