Amicus Therapeutics has shared interim data on a Batten disease gene therapy it acquired last year. The study has generated early evidence that the gene therapy may stabilize the motor and language function of children with the rare genetic disorder, but many questions remain unanswered.
Having made its name developing drugs to stabilize lysosomal storage disorders, Amicus moved into gene therapies last year through the $100 million acquisition of Celenex. The takeover gave Amicus a ready-made gene therapy pipeline spearheaded by two clinical-phase assets. Today, Amicus posted an early look at data on one of those assets, AAV-CLN6 gene therapy for CLN6 Batten disease.
The key early efficacy data relate to the effect of AAV-CLN6 on patient’s scores on the Hamburg scale, a measure of motor and language function. In seven of the eight patients treated with AAV-CLN6, the Hamburg score stabilized within one point of their pretreatment level.
As the study lacks a control arm, Amicus contrasted the results to the performance of the siblings of patients treated in the trial. For example, patient three scored five out of six on the scale at the time of treatment and was still at that level 24 months later. In contrast, the score of the sibling of patient three fell from five to two over the same 24-month window in their development.
That encouraging performance comes with several caveats. The durability of the effect will remain an open question while Amicus waits for longer-term follow-up. And Amicus is yet to share efficacy data on four patients treated in the trial, nor has it released results against other endpoints.
The other results released to date relate to the safety of AAV-CLN6. Amicus tracked two cases of grade 3 vomiting and one case of grade 3 epigastric pain that were possibly related to the treatment. The affected patients recovered from all three adverse events. No grade 4 or 5 adverse events have been seen so far.
Buoyed by the findings, Amicus plans to dose additional patients and advance talks with regulators. In parallel, Amicus will continue development of its other gene therapies, which target CLN3, CLN8 and CLN1 Batten disease.