In the online version of the journal Blood
, Raymond Wong MD and colleagues published their results of the open-label EXTEND study looking at the long term safety and efficacy of Promacta (eltrombopag) in adults with chronic/persistent immune thrombocytopenia (ITP).
ITP is a rare bleeding disorder in which blood does not clot properly due to an unusually low number of platelets or thrombocytes. Symptoms include excessive bruising and bleeding. Promacta is currently approved for ITP based on data showing its efficacy for up to 1 year. The data presented in Blood
included patients that had taken the drug for up to 8 years.
In the open-label extension studies of the phase 2/3 studies that led to the drug’s approval, data from 302 patients were included. The median length of treatment was 2.37 years (range: 2 days - 8.76 years) and the study observed that median platelet counts increased to ≥50×109
/L by week 2 and were sustained throughout the study. Overall, 85.8% achieved a response (platelet count ≥50×109
/L at least once in absence of rescue) and 52% achieved a continuous response (≥25 weeks). Bleeding symptoms decreased from a baseline level of 57% to 16% following 1 year of treatment.
While effective, 14% of patients withdrew from treatment because of adverse events (AEs) such as hepatobiliary adverse events (n=7), cataracts (n=4), deep vein thrombosis (n=3), cerebral infarction (n=2), headache (n=2), and myelofibrosis (n=2). The most common AEs were headache (28%), nasopharyngitis (25%) and upper respiratory tract infection (23%). During the study, only 6% of the ITP patients taking eltrombopag experienced a thromboembolic event.
In a news release
, James Bussel, M.D., professor emeritus of pediatrics at Weill Cornell Medicine said, "The EXTEND data published in Blood
validate Promacta as an important oral treatment option that, by often increasing platelet counts, significantly decreased bleeding rates and reduced the need for concurrent therapies in certain patients with chronic/persistent immune thrombocytopenia."
Vas Narasimhan, M.D., Global Head Drug Development and Chief Medical Officer, Novartis added, "The EXTEND results reinforce Promacta as a trusted treatment option that can be used over the long-term for those living with this chronic and rare disease."
Wong RSM, Saleh MN, Khefir A, et al. Safety and efficacy of long-term treatment of chronic/persistent ITP with eltrombopag: final results of the EXTEND study. Blood
. October 2017; Published online ahead of print. doi: https://doi.org/10.1182/blood-2017-04-748707
Image courtesy Wikimedia commons.
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