The past year and a half have included a variety of tests intended to establish a updated compendium of measurements before I transition from Lumizyme to Nexviazyme. My first Nexviazyme infusion is now scheduled for 1 November. As I proceed with the new medication, we will be able to compare future measurements in these categories against these new baselines. These before-and-after comparisons help build justifications for insurance companies that want a demonstration that the treatment is at least stabilizing my condition. They also provide a valuable frame of reference for me and for my physicians regarding the efficacy of the new drug and a comparison to Lumizyme.

Among the tests that I’ve had completed are:

• Brain MRI. I’m required to have a brain MRI every two years or so. In very remote cases, patients receiving enzyme replacement therapy (ERT) have developed brain aneurisms. A biennial brain MRI is intended to preemptively identify developing aneurisms before they become problematic. I’ll mention for the record that brain MRI’s are not a lot of fun. A brain MRI is like a standard MRI on steroids. It requires the same basic procedure which involved laying prone on a narrow table and being rolled into a tight cylinder. An MRI subject is required to stay completely still while three-dimensional images are taken of the body area of concern. With a brain MRI, because the subject area is the brain, the procedure involves placing a mesh cage over the skull and having it screwed into place so there can be absolutely no movement of the head. In my case, because I am dependent on the use of a ventilator, we have to rig up a hose to a ventilator that is stationed outside the imaging room; no metal or magnetic devises can be in the same room as the MRI machine. So imagine being placed on a narrow table, an unfamiliar ventilation hose rigged up to your nose to provide your only source of breathing, having a cage screwed into place over your face so you are completely unable to move, and then being rolled into a narrow cylinder for 15-20 minutes with no ability to communicate with the technicians. These are occasions when I’m grateful that I have practiced mindfulness meditation. I’ve developed the ability to pretty much remove my awareness from my body and dwell elsewhere during this procedure.
• Echocardiogram. This procedure involves ultrasound imaging of the heart. This study is also conducted biennially. It involves laying on a lab table on your side while a technician runs an ultrasound wand over the chest and between the ribs to visually assess the heart. I live with a mild heart murmur which is not a serious issue. But my periodic Echocardiograms monitor that valve leak and also insure that my heart is in healthy condition.
• Comprehensive Muscle Strength Tests. Ideally, these are conducted annually. One of the main reasons I sought out and found a new Pompe Disease specialist is that my former specialist became increasingly unresponsive. Pompe Disease can be effectively managed but it requires proactive management. Over the past few years, my former specialist stopped facilitating routine testing and refused to respond to my concerns about the renewed onset of muscle weakness after seven years of Lumizyme treatments. Among the necessary tests that fell by the wayside were my annual comprehensive muscle strength tests. These tests monitor muscle strength in specific areas of the body known to be affected by ongoing progression of Pompe Disease (e.g., biceps, triceps, shoulders, hands, thighs, hips, calves, feet, neck, etc.). These tests also monitor range of motion. At this point, I haven’t had comprehensive muscle tests in about four years, despite my ongoing efforts to have them done. My new Pompe Disease specialist has ordered these tests and intends to routinely monitor muscle strength as I transition to Nexviazyme.
• HEX4 Urine Tests. This test is used to indirectly measure and monitor the degree of skeletal muscle glycogen clearance. Pompe Disease is the product of an enzyme deficiency (acid alpha-glucosidase [GAA]) the absence of which inadequately assists the body in clearing glycogen from muscle tissue. The accumulation of glycogen in the muscle tissue of Pompe Disease patients is toxic and causes muscle wasting and fatigue. The HEX4 urine test is used to indicate the degree to which enzyme replacement therapy (ERT) – via Lumizyme or Nexviazyme – is effectively assisting the body in clearing glycogen from muscle tissue. I will have this lab test completed before my first Nexviazyme infusion on 1 November and on a quarterly basis thereafter.

Other Proactive Health Maintenance

When one lives with a progressive neuromuscular disease and especially one that compromises one’s ability to breath, it is all the more important to take preemptive care of one’s self. I would have been doing the following items anyway but in anticipation of transitioning to a new enzyme replacement therapy medication, I’ve been diligent about completing these measures.

• Annual Flu Vaccine. This past week, I received my annual flu vaccine.
• Long-term Pneumonia Vaccines. I’ve received both the Prevnar 13 and the Pneumovax 23 vaccines. Having weathered a handful of serious bouts of pneumonia including one near-fatal case in 1996 that required intubation and three weeks in an ICU, I don’t take any chances.
• Covid-19 Vaccines. I completed my two-vaccine regimen of the Moderna vaccine back in April 2021. As I make this entry, the FDA has just approved a booster shot from Moderna that will consist of a half-dose. In the next two weeks, I will reach my six-month marker since completing my original Moderna regimen. My hope is that I’ll be eligible for the booster as a candidate with special medical needs.
• Physical Therapy. I attend physical therapy sessions twice a week to help maintain the muscle strength and range of motion that I still have. And since my Friday appointment begins in thirty minutes, I’m going to conclude this entry for now!

Thanks for following along!

~ Brian