• Amicus Therapeutics’ leading experimental gene therapy appeared to halt the progression of a deadly disease in treated children, according to an interim data analysis presented Thursday by the company.
• The results are still too early to draw definitive conclusions, but Amicus CEO John Crowley said in an interview the early data support the treatment’s effectiveness. Thursday’s analysis included results from the first eight children with CLN6 Batten disease treated in a Phase 1/2 study with Amicus’ one-time treatment.
• In seven of eight patients, motor and language function stabilized rather than declined, as would typically be expected. The one child who suffered losses in her abilities received treatment at six-and-a-half years old, the oldest among the eight patients, suggesting the importance of early intervention, Amicus executives said.

Batten disease is a severe neurological disease. Children affected with the inherited lysosomal storage disorder are born appearing healthy, before their abilities to walk, speak, think and see progressively deteriorate.

Typically diagnosed at around age 4 or 5, the disease is usually fatal by age ten. There are no therapies approved by the Food and Drug Administration for all but one of the disease’s more than a dozen subtypes, which are defined by different genetic mutations.

In what’s called CLN2 Batten disease, BioMarin Pharmaceutical’s enzyme replacement therapy Brineura (cerliponase alfa) won U.S. approval in April 2017.

For patients with CLN6, however, there aren’t any options. Amicus estimates there are about 1,000 global cases of CLN6 disease.

Amicus hopes to change the course of disease with its gene therapy, Crowley said. Depending on the time of intervention, that could either translate into potentially curing children treated early, or preventing further deterioration in older patients.

“Time is neurons,” said Crowley in an interview with BioPharma Dive on Thursday. “When there is brain death, we don’t think it’s going to be reversible. It’s important to treat these children as soon as we can and to halt the progression of the disease.”

The early data disclosed Thursday suggest the therapy’s potential to at least stabilize the disease, as measured by a six-point score that gauges mobility and speech ability.

Instead of a control group, Amicus set its results against natural history data as well as comparing across a few sets of siblings. A typical untreated child will see scores drop from 6 to 0 within a few years, averaging about 1 to 2 points of decline per year.

Amicus’ initial findings come from the first eight treated patients. For the six children who had two years of follow-up, two maintained their initial score, three dropped one point and one declined by two points.

The two additional patients included in the data cut have been studied for more than a year. One saw their score increase from a 5 to a 6, and the other remained at her initial score.

On safety, Amicus said its therapy has been generally well-tolerated. Among the 12 patients who have received the therapy, four experienced nine severe adverse events. Three of events (two cases of vomiting and one of epigastric pain) were considered potentially related to treatment. All three subsequently resolved.

All told, the update looks positive for Amicus’ program, Cantor Fitzgerald analyst Elemer Piros wrote in a Thursday note to investors.

The Phase 1/2 study protocol calls for 12 patients, who have all enrolled. The company stated they expect to dose a limited number of additional patients as well. Amicus plans to give another data update on the first eight patients this fall, at its analyst day and at the Child Neurology Society’s annual meeting in October.

Amicus is also developing gene therapies for three more variations of Batten disease: CLN3, CLN8 and CLN1. The CLN3 program entered the clinic at the beginning of 2019.