TSHA-118 gene therapy for CLN1 disease to be tested in Canadian trial

With the approval of Health Canada, Taysha Gene Therapies will begin a Phase 1/2 clinical trial testing TSHA-118, its investigational gene therapy for CLN1 disease, also known as childhood Batten disease.

This first test will be launched at Queen’s University, in Ontario, under the coordination of Jagdeep Walia, MD, with initial data expected by June, the company said in a Press release.

Taysha also has an opening investigational new drug request (IND) in the United States for TSHA-118.

“We believe TSHA-118 offers the potential for a disease-modifying therapeutic approach for patients affected by this disease,” said RA Session II, President, Founder and CEO of Taysha.

“We look forward to working in collaboration with Queen’s University and await the availability of preliminary clinical safety tests and the PPT1 enzyme. [the protein that is absent or working poorly in CLN1] activity data for the first half of 2022, ”said Session.

TSHA-118 uses a harmless viral vector called AAV9 to deliver a functional copy of the CLN1 gene to cells of the central nervous system, which is the part of the nervous system comprising the brain and spinal cord.

“CLN1 disease is caused by mutations in the CLN1 gene, which encodes the soluble lysosomal enzyme palmitoyl-protein thioesterase-1, or PPT1, ”said Suyash Prasad, chief medical officer and head of research and development at Taysha. “Presentation of a function CLN1 gene with TSHA-118 treatment offers a potentially effective therapeutic approach that addresses the root cause of the disease.

The AAV9 viral vector has the ability to cross the blood-brain barrier, allowing gene therapy to enter the central nervous system, the company says in its website. The blood brain barrier is a membrane made up of cells that protect the brain from potentially harmful substances in the blood while allowing nutrients to reach the brain.

Preclinical studies in mice lacking CLN1 showed that TSHA-118 administered into the spinal canal (intrathecally) prolonged survival, improved behavior and preserved motor function. The therapy resulted in a sustained increase in the levels of active PPT1.

It was also safe and well tolerated with no associated side effects.

A study of natural history (NCT04613089) at the University of Hamburg, Germany, collecting data on CLN1 and other types of Batten disease from the international DEM-CHILD database.

Another study (NCT01873924) at the University of Rochester, USA, examines the age of symptom onset and the relationship between age and symptom severity. Patients whose symptoms begin in adulthood appear to have PPT1 activity of 5% to 8%, suggesting that an increase in PPT1 activity of 0.1% to 5% may have therapeutic potential.

“In preclinical models of CLN1, TSHA-118 significantly prolonged survival and improved behavior,” said Prasad. “We are strongly encouraged by the therapeutic potential of TSHA-118 and expect PPT1 activity of 5% or greater to normalize survival and dramatically improve clinical phenotype based on natural history data. “

Now that the therapy is entering human studies, the goal is to assess how safe it is and whether it leads to increased PPT1 activity in serum – the clear, liquid part of the blood -. and cerebrospinal fluid, which is the fluid that surrounds the brain and spinal cord.

The phase 1/2 trial will be open, which means researchers and patients are aware of the treatment being given.

TSHA-118 has received orphan drug, rare pediatric disease, and fast track designations from the United States Food and Drug Administration for CLN1 disease, as well as orphan drug status from the European Commission. There is currently no cure for childhood Batten disease.