Theranexus and BBDF Win FDA Approval on Efficacy Endpoints for the Phase III Trial to Evaluate Batten-1 in CLN3 Batten Disease

• Phase III's primary endpoint will be visual acuity, with secondary endpoints including assessment of cognitive and motor functions,
• The FDA confirmed that this sole Phase III trial would secure Batten-1 approval for Batten CLN3 disease.

LYON, FRANCE and AUSTIN, TX / ACCESSWIRE / May 9, 2023 / Theranexus, a biopharmaceutical company innovating in the treatment of neurological diseases, and the Beyond Batten Disease Foundation (BBDF), have today announced receipt of approval from the Food and Drug Administration (FDA) for the design and primary and secondary endpoints of the pivotal Phase III trial for Batten disease CLN3, at a meeting with the Division of Rare Diseases and Medical Genetics (DRDMG) held in mid-April.

" We are delighted with the constructive discussions we had with the FDA on defining the endpoints of Batten-1 and the design of our pivotal Phase III trial. Its valuable guidance allows us to get fully prepared for the trial launch," explained Theranexus' Chief Medical Officer Marie Sebille.

" We would like to thank the FDA for its support, which is fundamental to the development of our Batten-1 drug candidate, the only asset in active clinical development for Batten disease (CLN3). Our pivotal Phase III trial will enable us to gain approval for Batten-1, and also deliver rich news flow throughout the duration of the Phase III trial thanks to the parallel open-label patient cohort. More generally, we have no doubt that we can deliver a therapeutic response for patients suffering from Batten disease," added Theranexus' CEO Mathieu Charvériat.

Theranexus and BBDF worked with the FDA's DRDMG to define the following criteria for the protocol of the Phase III multicenter trial for evaluating Batten-1 in patients with juvenile Batten disease (CLN3):

• The trial will be a randomized, double-blind study conducted versus placebo in 2 parallel groups to assess the efficacy of Batten-1 at a dose of 15 mg/kg and up to 600 mg/day for a 2-year treatment period,
• The target population will be a pediatric cohort involving approximately 60 patients aged 4 to 16 years, with randomization stratified into 3 age groups of 4 to 8 years, 9 to 12 years and 13 to 16 years to achieve suitable representation for all age groups assessed,
• The primary endpoint will be visual acuity, measured using either the quantitative LogMAR[1] scale, or a qualitative scale in the most impaired patients for whom quantitative assessment is not possible,
• The secondary endpoints will include cognitive function, assessed by the Verbal Comprehension Index from the Wechsler Intelligence Scale for Children according to age, motor function assessed by a selection of motor items from the Unified Batten Disease Rating Scale (UBDRS), and visual function, assessed by OCT scan,
• An assessment of functional ability in everyday activities and a Quality-of-Life measurement will also be performed.

An additional open-label cohort of 9 patients' representative of the different age groups of the target population will be enrolled in parallel. This will allow us to enrich the statistical analysis plan, in particular in comparison with natural history data, for the primary and secondary endpoints on trial completion, and produce interim results every 6 months, including measurements of biomarkers (notably glycosphingolipids given their toxic accumulation resulting in neuronal death) and efficacy data on the same criteria as the main 60-patient cohort.