The University of Hong Kong said on Monday that it has successfully developed a drug — also the city’s first locally invented and manufactured prescription drug — for the treatment of acute promyelocytic leukemia, with a 97 percent cure rate.
The medicine — an oral formulation of arsenic trioxide — has also obtained orphan drug designations from the United States Food and Drug Administration and the European Medicines Agency (EMA), and has been approved for clinical use in Singapore, Malaysia and Taiwan region, and in neighboring Guangdong cities, marking Hong Kong’s historic step into the global arena of medicine.
Acute promyelocytic leukemia, or APL, is a rare type of leukemia that has a high fatality rate.
Speaking at a news conference on Monday, HKU said its research team has incorporated oral-arsenic-trioxide (Oral-ATO) into APL patients’ treatment, with an overall survival rate exceeding 97 percent and a significant reduction in side effects and treatment burden.
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The research team is now testing a pioneering treatment in Hong Kong with an entire oral regimen comprising oral-arsenic-trioxide, all-trans retinoic acid and ascorbic acid for APL.
Harry Gill, clinical associate professor from HKU’s Department of Medicine and the study’s lead investigator, said the all-oral regimen can be applied in an outpatient setting for all risk groups of APL patients and minimize the need for chemotherapy in all cases, including children.
Hong Kong reports around 25 to 30 new APL cases per year. Therapies such as chemotherapy have been commonly used in treatment, achieving remission rates of over 90 percent, but about 5 to10 percent of these patients experience a relapse, and the long-term overall survival rate is about 80 percent, added Gill.
There is also an early death rate as high as 16 percent due to complications, which Gill called a major challenge in APL’s diagnosis and treatment.
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As the city’s first self-developed prescription drug, the groundbreaking Oral-ATO is also the first drug in Hong Kong to have obtained key designations from the US’ and Europe’s drug administrations, setting the stage for its global studies and promotion, according to HKU.
Over the past 20 years, researchers from HKU’s Li Ka Shing Faculty of Medicine have conducted extensive research on the use of oral-arsenic-trioxide to cure APL.
Gill said HKU reported that in a 15-year prospective follow-up study of over 400 patients with relapsed APL, those who used the therapy based on oral-arsenic-trioxide experienced a 100 percent remission rate and a five-year overall survival rate of 80 percent — a result achieved without bone marrow transplantation, another major treatment for APL.
The research team then switched to administering oral-arsenic-trioxide as a maintenance treatment for APL patients who had experienced their first complete remission, resulting in a 90 percent five-year leukemia-free survival rate and a 97 percent overall survival rate.
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Based on their previous findings, the team has developed a treatment plan, focusing on early initiation of treatment, which can effectively reduce the early death rate from APL, which previously reached 20 to 30 percent.
The drug, in addition to obtaining key designations from the US’ and Europe’s drug administrations, is being approved by the Guangdong Provincial Medical Products Administration for clinical use in the mainland cities of the Guangdong-Hong Kong-Macao Greater Bay Area via the HKU-Shenzhen Hospital.
Oral-ATO is also available for APL research and clinical use in Singapore, Malaysia and Taiwan region.
