The positive clinical outcomes were maintained in patients with late-onset Pompe disease who continued treatment with avalglucosidase alfa, according to results from the extension period of a randomized, phase 3 clinical trial called COMET.
Positive clinical outcomes were also observed in patients who switched from alglucosidase alfa but to a lesser extent, the researchers noted. “No new safety concerns were observed,” the investigators noted.
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Results from the COMET trial had shown that avalglucosidase alfa treatment for 49 weeks leads to clinically meaningful improvements in the percent predicted upright forced vital capacity (FVC) and 6-minute walk distance compared with alglucosidase alfa.
Here, in a report published in JAMA Neurology, the investigators reported safety and efficacy data after 97 weeks of treatment with avalglucosidase alfa.
Of the 100 patients from the double-blind treatment period of the COMET trial, almost all (n=95) entered the extension period.
At the start of this study, the mean percent predicted upright FVC was similar between the treatment arms. The 6-minute walk distance was longer in the avalglucosidase alfa arm.
The least squares mean percent predicted FVC increased by 2.65 from baseline to week 97 for patients who continued on avalglucosidase alfa and by 0.36 for those who switched to avalglucosidase alfa from alglucosidase alfa.
Similarly, the least squares mean 6-minute walk distance increased by 18.6 m for those who stayed on avalglucosidase alfa the whole time and by 4.56 m for those who switched to avalglucosidase alfa from alglucosidase alfa.
For patients who switched to avalglucosidase alfa, percent predicted FVC remained stable with a least squares mean change of 0.09 from week 49 to week 97, while the 6-minute walk distance improved with a least squares mean change of 5.33 m from week 49 to week 97.
Treatment-related adverse events were seen in 56.9% of patients who continued on avalglucosidase alfa and in 56.8% of patients who switched from alglucosidase alfa.
Kishnani PS, Diaz-Manera J, Toscano A, et al. Efficacy and safety of avalglucosidase alfa in patients with late-onset Pompe disease after 97 weeks: a phase 3 randomized clinical trial. JAMA Neurol. Published online April 10, 2023. doi:10.1001/jamaneurol.2023.0552
Study to compare the efficacy and safety of enzyme replacement therapies avalglucosidase alfa and alglucosidase alfa administered every other week in patients with late-onset Pompe disease who have not been previously treated for Pompe disease (COMET). US National Library of Medicine. Updated March 17, 2023. Accessed May 5, 2023.