HEQ speaks with Allan Muir, Chair of the Board of Trustees at the UK’s Pompe Support Network, about the burden and treatment of Pompe disease.
Pompe disease, also known as glycogen storage disease type II, is one of around 16 recognised glycogen storage diseases: rare metabolic disorders in which enzyme deficiencies slow or halt the synthesis or breakdown of glycogen or glucose. In the case of Pompe disease, which affects around one in every 13,000 people, a deficiency of the lysosomal acid alpha-glucosidase enzyme, which breaks down glycogen in the lysosome, causes an accumulation of glycogen in the lysosome – this build-up results in progressive weakness of the muscles, causing mobility, respiratory and cardiac issues, among others.
HEQ speaks with Allan Muir, Chair of the Board of Trustees at the UK’s Pompe Support Network, about the burden and treatment of the disease.
What support or guidance does the Pompe Support Network offer for patients and healthcare providers?
As our name implies, the Pompe Support Network is an organisation that brings together people from throughout the UK Pompe community and beyond. A recent diagnosis of Pompe disease often incurs a great need for reassurance and information that can be provided by medical professionals, researchers and patient experts; all stakeholders working together is essential for the optimal outcome.
The information we provide is gathered from experts in academic research, healthcare professionals, industry partners, and individuals living with Pompe disease. We offer support and advice to individuals and families, as well as signposting to other organisations who offer access to specific support services, such as mental health and welfare benefits. We work with the patient community to understand where gaps in care provision and treatment exist; we organise meetings with invited guest speakers and have a growing video library of recorded presentations. We are also developing an audio library, ‘Pompe Voices’, consisting of informal conversations between individuals discussing their life experiences of Pompe disease with friends and family.
The information we provide helps both people with a new diagnosis and people already living with Pompe disease to understand the disease; we present techniques to improve their quality of life and discuss patients’ experiences with available treatments. We also publish information about potential treatments being investigated by academic institutions and biotechnology companies; we have links to all the centres running clinical studies in the UK. Healthcare professionals, family members, colleagues and researchers all benefit from the information we offer. We are also supported by medical advisors around the world.
The Pompe Support Network maintains close links to healthcare specialists who have interests in Pompe disease. We work directly and through national and international networks to ensure that the care, management and treatment of their patients is of the highest quality. As a member of the UK Lysosomal Storage Disorder (LSD) Patient Collaborative, an action group of nine UK charities supporting ultra-rare diseases, we have a strong voice when advising NHS professionals, commissioners and medicines regulators such as the National Institute for Health and Care Excellence (NICE), the Scottish Medicines Consortium (SMC) and the All-Wales Medicines Strategy Group (AWMSG).
What are the key symptoms or indications of Pompe disease in infants and adults? What treatments are recommended?
Pompe disease elicits a broad spectrum of symptoms across all age groups, from babies born with very poor muscle tone, disordered breathing and cardiac involvement, through to adults who only become aware of serious symptoms in later life. Infants generally fall into two categories: classic infantile Pompe disease is the most severe and would result in respiratory and cardiac failure if not treated with enzyme replacement therapy (ERT) soon after birth. Children with less severe forms of the disease need to be treated with ERT to slow their rapid disease progression and reduce the risk of scoliosis and other skeletal deformities. However, even with treatment they often continue to lose muscle function, especially through periods of rapid growth.
Adults may suffer with increasing muscle weakness and breathing difficulty for many years before a confirmed diagnosis is made, despite the wide availability of enzymatic diagnostic tests and genetic sequencing. Older children and adults can have diverse symptoms, some having predominantly skeletal muscle weakness and others suffering more with their respiratory function; many have both. Other common symptoms can include morning headaches, muscle pain, gastrointestinal issues, swallowing and speech difficulties.
In 2006 an (ERT) was approved for use by the Highly Specialised Service for Lysosomal Storage Diseases, a service provided through eight specialist centres in England, commissioned by NHS England, as well as by centres in the devolved nations. The ERT, Myozyme, was developed by Sanofi Genzyme and can be accessed by all patients with a confirmed diagnosis of Pompe disease.
No other medicines are currently available for Pompe, although several new therapies are undergoing clinical trials, including next-generation ERT and gene therapies. Non-medical therapies, such as dietary and exercise-based therapies, can also provide modest benefits to patients.
Has the COVID-19 pandemic had a significant impact on people living with Pompe disease?
A recent survey of the UK Pompe community showed that people suffered greatly from increased isolation, difficulties with food supplies, and mental and emotional wellbeing. During the first wave of the pandemic, access to treatment was reduced to protect patients who predominantly receive ERT at home once per fortnight. However, it quickly became apparent that patients were becoming more vulnerable to falls, muscle pain, and other symptoms; treatments were resumed after several months and once personal protective equipment (PPE) for homecare nurses was believed to be adequate. Thankfully, no patients have yet reported contracting COVID-19, but people with Pompe disease are classed as Clinically Extremely Vulnerable in the UK and have been shielding continuously since the first lockdown. Families shielding a child with Pompe disease experienced great difficulties when siblings returned to school, although most children were not considered to be vulnerable to COVID-19.
Hospital visits were mostly replaced by virtual consultations, a move that many patients found beneficial because travel to and within hospitals is highly challenging when living with a neuromuscular condition. Most patients and families live many miles from their specialist centre and multidisciplinary medical team.
Aside from COVID-19, what are the most pressing challenges currently facing the management and treatment of Pompe disease?
Generally, the current treatment of Pompe disease is well tolerated, but there are individuals for whom an improved treatment regimen would offer significant benefit. As young children grow, their bodies impose increased demands on their metabolism, they may suffer from rapid disease progression, muscle weakness and skeletal deformities, such as scoliosis – this is because their muscles are unable to adequately support their spine as it grows. Many who were rescued by the amazing treatment available had been very active in early childhood, but are now sadly becoming wheelchair users.
There are infants in the USA, the Netherlands and Taiwan who are prescribed a much higher dosage of ERT, and this has been shown to overcome this significant disease progression. However, Myozyme is an extremely expensive therapy that many health providers, including the NHS, refuse to fund anything over and above the licensed dose.
Are there any notable developments or current issues in research or treatment of Pompe disease which you would like to highlight?
Research into Pompe disease is very active across many areas and promises a number of exciting developments in the near future. Second-generation ERTs are under investigation, with two soon to apply for market authorisations in the USA and Europe. Several adeno-associated virus (AAV) and lentiviral gene therapies are already being studied in the clinic and so we expect to hear progress from those very soon.
Other research that would bring considerable relief to patients is in muscle regeneration. The science is becoming better understood and ways to activate the patients’ own muscle stem cells is being investigated.
Allan Muir
Chair of the Board of Trustees
Pompe Support Network
https://pompe.uk/
This article is from issue 17 of Health Europa. Click here to get your free subscription today.
