Questions and Answers with Dr. Feldman: Mirum FXS Clinical Trial

Nov 20, 2025
7:30 pm to 8:15 pm PT

Online event

We are excited to announce that the Mirum clinical trial for Fragile X syndrome (FXS) is now enrolling in Irvine, California, under the leadership of Dr. Gary Feldman, Principal Investigator. This study is hosted and organized by the Fragile X Association of Southern California (FXSOCAL) and offers families the opportunity to explore an innovative treatment option and make informed decisions for their loved ones with FXS.

Online Register: https://us02web.zoom.us/meeting/register/3-NmYTgEQMWN8XsBgpx8AA

What to Expect:

Dr. Feldman will introduce the Mirum FXS study and answer questions.
Maggie Wang, NP, Site Director at Amnova Clinical Research, will explain the study details and how to participate.
Learn about study benefits, including stipends, transportation, and meal reimbursement.

About the Mirum Study

Who Can Join:

Gender: Male
Age: 13–45 years
- Ages 13–16: Open-label
- Ages 16–45: Randomized phase

Study Drug: MRM-3379 (oral medication taken twice daily)
Duration: 5 months
Visits: 4 onsite visits + 4 phone follow-ups

How It Works

MRM-3379 is designed to selectively block an enzyme called PDE4D, which affects communication between nerve cells in areas of the brain responsible for learning, memory, and emotional control. By reducing PDE4D activity, MRM-3379 can increase levels of cAMP, a key molecule that helps nerve cells communicate more effectively — potentially improving FXS symptoms.

In preclinical studies, MRM-3379 achieved brain concentrations five times higher than in blood.
In Phase 1 trials, it was well tolerated in both single and multiple-dose testing.

Possible Benefits for Participants

Families may see improvements in: