Heather Lau, MD, MS, on Addressing Unmet Needs in MPSIIIA With Gene Therapy

“The idea is that we administer this drug intravenously in a one-time infusion and then that viral vector will then transduce a variety of cells, including the brain cells. This will lead the transgene to be transduced and translated into a fully functioning SGSH enzyme. That would lead to the ability to reduce the substrate that's being deposited throughout those cells.”

Mucopolysaccharidosis type IIIA (MPS IIIA, also known as Sanfilippo syndrome) is a rare genetic disorder caused by mutations in SGSH, the gene that encodes for an enzyme known as sulfamidase (SGSH). In the absence of functional SGSH enzyme, which is normally responsible for breaking down the glycosaminoglycan heparan sulphate (HS), the cells of patients with MPSIIIA begin to accumulate excess HS. This accumulation of the substrate causes neurocognitive decline and early death. Currently, standard of care treatment for MPSIIIA is focused on alleviating symptoms, and may take the form of physical therapy, behavioral drugs, and medications for seizures and sleep. No treatments that directly target the root cause of the disease are currently approved by the FDA. As such, great unmet need remains for this patient population.

Ultragenyx attempting to address this unmet need with UX111 (also known as ABO-102), its intravenously administered self-complementary adeno-associated virus (AAV) vector-based gene therapy. UX111, which utilizes an AAV9 vector and delivers functional hSGSH, is currently being evaluated in the phase 1/2/3 Transpher A clinical trial (NCT02716246). The latest results for Transpher A were recently presented at the 2024 WORLDSymposium, held February 4-9, in San Diego, California, by Heather Lau, MD, MS, the executive director of global clinical development at Ultragenyx Pharmaceutical.

Shortly after the close of the conference, CGTLive™ sat down with Lau to learn more about UX111 and how it could help to address unmet needs in MPSIIIA. Lau discussed the current landscape of care for the disease and described the design of the gene therapy.