AB-1003 gene therapy being tested for LGMD

15 October 2025

AB-1003 is a potential gene therapy for limb-girdle muscular dystrophy R9 (LGMDR9). People with LGMDR9 have changes in a gene called FKRP, which affects how their bodies make fukutin-related protein. This protein helps keep muscles strong and properly structured.

AB-1003 is designed to deliver a working copy of the FKRP gene using a harmless virus called an AAV vector. The treatment is given once, through a drip into the bloodstream (known as an intravenous infusion).

An early clinical trial is testing AB-1003 to check if it’s safe and to find the best dose. So far, five people have received the treatment and were followed for 52 weeks. Early results suggest the treatment is well-tolerated, with the most common side effects being headaches, nausea and falls.

Three participants had higher levels of transaminase, which can be a sign of stress or damage in the liver. However, none of them had other symptoms, and doctors were able to manage and reduce these levels.

The trial plans to include 14 participants across the US and will test different doses of AB-1003 to learn more about how it works, its safety and how much should be given.