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Treatment hampered by lack of definition of rare disease in Hong Kong

By Macau Mak & Total Lam

For Terry Lai Ka-wai, doing simple things that most of us take for granted can be a struggle – for instance, walking. “I used to sweat heavily after walking outside for five minutes in winter. I’d be like someone who’s just played ball games and have to change my clothes,” he says.

Lai, who is now 24, was diagnosed with Pompe disease when he was nine. Pompe is an inherited metabolic disorder caused by the deficiency of an enzyme used to break down glycogen to glucose in lysosomes. The lack of the enzyme causes the buildup of the glycogen in the body’s cells which can impair organs from functioning normally.

In his teens, Lai suffered from muscle weakness, a drooping jaw, curved spine and reduced lung volume and had difficulty walking and speaking clearly.

Terry Lai Ka-wai
Terry Lai Ka-wai

The Hospital Authority (HA) started providing Lai with subsidised medical treatment in 2010, and his physical condition has improved since then. With increased stamina, he is now working in a ticketing office after finishing his degree at Hong Kong Polytechnic University.

With only around one in 40,000 people worldwide suffering from Pompe, it is regarded as a rare disease in some places like Taiwan and the United States.

There is no universal definition for a rare disease. Most are caused by genetic mutations, some of which are inherited. For the United States, any disease affecting about one in 1,500 people is defined as a rare disease; for the European Union, the figure is one in 2,000 people; for Taiwan, one in 10,000 people. Currently, more than 6,000 rare diseases are known, although the number of patients with any particular rare disease is relatively low.

In Hong Kong, the HA has not defined what counts as a rare disease, so related statistics are unavailable. However, it has been providing enzyme replacement therapy (ERT) to patients suffering from certain lysosomal storage diseases since 2008. The ERT drugs – which provide patients with the enzyme that is deficient or defective in their bodies – are categorized as special drugs in the HA Drug Formulary. Only six diseases are addressed, namely Pompe, Gaucher, Fabry and Mucopolysaccharidosis (MPS) Types I, II and VI. In 2008-2009 and 2010-2011, the government allocated additional recurrent funding of HK$10 million and HK$35 million respectively for the HA to provide the costly therapy.

However, patients are not automatically prescribed the treatment. In 2007, the HA established an expert panel to assess applications for ERT on a case-by-case basis. The panel comprises paediatricians, physicians, clinical pharmacology experts and pharmacists. The panel has handled 27 applications and 17 patients were still undergoing ERT in December 2013. The HA adopts a year-by-year contract system to provide ERT for successful applicants at highly subsidised charges.

Although Terry Lai is one of the successful applicants, he finds the system very stressful. “We would not know whether our contract is renewed until the last minute. It’s just creating fear and pressure for the patients,” he says. Lai adds he knows the HA stops renewing contracts for patients if their body function worsens. As the annual cost of ERT is around HK$2 million without a subsidy, Lai would be unable to continue treatment without government support. So he is under pressure to make sure he can make improvements in walking and lung function tests so that his contract can be renewed.