Ultragenyx stumbles in P3 trial for severe muscle disease

Ultragenyx has revealed results from a Phase 3 trial into the treatment of GNE myopathy showed that its compound did not successfully meet the primary or secondary endpoints of the study.

The failure in the clinic means that the biotech now plans to abandon all development of the drug and open up "valuable natural history data and development tools for the development of other therapies" to investigators and patient groups.

The particular candidate that was tested was aceneuramic acid extended release (Ace-ER), with the hope that it could improve upper extremity muscle strength for those suffering from GNE myopathy. The drug had previously shown some promise in Phase 2 trials but fell at the key hurdle.

The clinical study involved 89 patients, with the rare condition GNE myopathy, with the primary and secondary endpoints being focused on muscle strength throughout the body. The participants were trialled with either 6g dose of Ace-ER per day against a placebo over the course of 48 weeks. The results were not able to demonstrate any statistically significant benefits of the treatment.

GNE myopathy is a rare condition wherein a person’s body is not able to complete the first step of sialic acid biosynthesis needed for the modification of proteins and fats. This leads to muscle weakness developing between 20 and 30 years old, as muscle wastage progresses this can lead to individuals requiring a wheelchair. There are currently no treatments for the condition.

"We are disappointed by these results, as we had hoped that Ace-ER would offer a new option for GNEM patients. We would like to thank the patients, caregivers, and investigators involved in the Ace-ER development program," said Emil D. Kakkis, Chief Executive Officer and President of Ultragenyx. "This outcome does not affect our overall strategy, as the company moves forward with multiple preclinical and clinical programs and regulatory filings."

As Kakkis states, the company has other products in the pipeline that may be able to succeed where Ace-ER has failed. It received positive results in Phase 3 trial for burosumab, an immunotherapy for patients with bone mineralization disorders X-Linked hypophosphatemia and tumour-induced osteomalacia. Alongside, Kyowa Hakko Kirin, a co-developer of the treatment, it plans to submit a BLA.