Emicizumab breathes new hope for people with haemophilia A
The monoclonal antibody emicizumab (Hemlibra®, Roche) is now available in Malaysia. The drug is indicated for routine prophylaxis in the prevention and reduction of bleeding episodes in people with haemophilia A with factor VIII inhibitors.
Emicizumab is the first new medicine in more than 2 decades to be approved for use in children and adults with haemophilia A with inhibitors. Speaking at the launch, Dr Jameela Sathar, consultant haematologist at Ampang Hospital, said: “According to the report on the Annual Global Survey 2017 of World Federation of Haemophilia, there are 158,225 persons with haemophilia A worldwide. In Malaysia, the prevalence of haemophilia A stood at 1,295 persons in 2017.” [www1.wfh.org/publications/files/pdf-1714.pdf Accessed on 21 October]
However, this number is possibly the result of underdiagnosis, as going by the global average of one in 5,000 males and multiplying by half of Malaysia’s population (assuming half of our 33 million population are male), then the country should have closer to 3,000 haemophilia patients in its registry.
Jameela said: “People with haemophilia A can bleed into their muscles and joints, causing difficulty to use their muscles and joints. They can even bleed spontaneously. Without treatment, the quality of life of people with severe haemophilia may be affected. They may find it difficult to go to school or work regularly, become physically disabled, have trouble walking or doing simple activities.”
Also present at the launch was Dr Veena Selvaratnam, consultant haematologist at Hospital Ampang. She revealed the number of persons with haemophilia A with inhibitors stood at 83 in 2017. While this number is small, the patients face significant challenges in preventing bleeds and typically require multiple infusions of bypassing products (special blood products that can bypass the inhibitors) per week, which is burdensome to young children and their caregivers. The availability of emicizumab is a boon for these patients as it is administered via subcutaneous injection once a week, thus making it more convenient for the patient and their caregivers.
Evidence for emicizumab’s approval came from the HAVEN 1 and HAVEN 2 studies. HAVEN 1 looked at the prophylaxis use of emicizumab in 109 adults and adolescents with haemophilia A with inhibitors. Emicizumab prophylaxis showed a statistically significant reduction in treated bleeds of 87 percent compared to no prophylaxis. In HAVEN 2, 54 out of 57 patients who were treated with the drug had zero treated bleeds. [Blood 2017;130(Suppl 1):Abstract 89]
Haemophilia is categorized into two major types—haemophilia A and B. Haemophilia A occurs due to a lack of factor VIII while haemophilia B is the result of a lack of factor IX. Persons with haemophilia tend to bleed into the joints, skin, mouth and gums; blood in the urine or stool; and frequent and hard-to-stop nosebleeds. [Available at www.cdc.gov/ncbddd/hemophilia/facts.html Accessed on 8 October]
Factor VIII replacement therapy is the main treatment for haemophilia A. However, the most serious complications for patients is the development of antibodies through their own immune system towards factor VIII replacement therapies. These antibodies known as inhibitors neutralizes the factor concentrate given to patients resulting in ineffective treatment, hence increasing the risk of morbidity and disability as well as the treatment cost. Approximately 1-in-3 people with severe haemophilia A will develop inhibitors to factor VIII replacement therapy, effectively making factor VIII replacement a non-option for use in these individuals.
HAVEN 1: A Study to Evaluate the Efficacy, Safety, and Pharmacokinetics of Prophylactic Emicizumab Versus no Prophylaxis in Hemophilia A Participants with Inhibitors
HAVEN 2: A Study of Emicizumab Administered Subcutaneously (SC) in Pediatric Participants With Hemophilia A and Factor VIII (FVIII) Inhibitors