Oxygen uptake at the peak of exercise and the 6-Minute Walk Distance (6MWD) are more sensitive than other markers in assessing clinical deterioration and long-term response to treatment in patients with infantile-onset Pompe disease, according to a new study published in the Journal of Personalized Medicine.

This is an important finding because it can be useful when assessing the effect of new strategies and dosing regimens for the treatment of the disease.

A progressive decline occurs in patients with infantile-onset Pompe disease, even with enzyme replacement therapy. This only current approved disease-modifying therapy for the condition suggests that the approach cannot keep up with the rate of glycogen accumulation in the body.

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Here, a team of researchers was led by Lea Bentur, MD, and Hanna Mandel, PhD. They conducted a retrospective-prospective study to assess the immediate and long-term effects of enzyme replacement therapy on exercise ability in patients with infantile-onset Pompe disease. To do so, they used the Cardiopulmonary Exercise Test, 6-Minute Walk Test (6MWT), Motor Function Test, and spirometry.

The results showed that the levels of alglucosidase alfa increased in the blood even after 2 days of enzyme replacement therapy. The forced expiratory volume, forced vital capacity, motor function, 6MWD, and oxygen uptake at the peak of exercise did not change. 

“Long-term evaluations showed stabilization in young patients but progressive deterioration in adolescents,” the researchers wrote. They added that clinical deterioration was mainly associated with deterioration in oxygen uptake at the peak of exercise and a decrease in the 6MWD. The deterioration in forced vital capacity and motor function was less pronounced in clinically deteriorating patients. 

“More studies are needed to clarify the sensitivity of the [oxygen uptake at the peak of exercise] and 6MWT for quantification of individualized response,” the researchers concluded.


Bar-Yoseph R, Tal G, Dumin E, et al. Individualized assessment of exercise capacity in response to acute and long-term enzyme replacement therapy in pediatric Pompe disease. J Pers Med. 2021;11(11):1105. doi:10.3390/jpm11111105