Givosiran increases quality of life, reduces attacks in acute hepatic porphyria
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LONDON — Long-term givosiran treatment provided sustained benefit and improved quality of life among patients with acute hepatic porphyria, according to research presented at the International Liver Congress.
“Acute hepatic porphyria is a rare genetic disorder that causes acute neurovisceral symptoms caused by defects in hepatic heme biosynthesis leading to accumulation of neurotoxic heme intermediates 5-aminolevulinic acid and porphobilinogen, which can be life-threatening in a small proportion of patients. It can also lead to chronic debilitating symptoms in a subtype of patients,” Manish Thapar, MD, director of the Center for Genetic and Metabolic Liver Disease at Thomas Jefferson University, said during the International Liver Congress press conference. “In this meeting, we will be presenting data from a long-term study of a novel treatment called givosiran, which has been approved and is commercially available.”
In the phase 3, randomized, placebo-controlled ENVISION study, givosiran treatment led to sustained clinical benefit among patients aged 12 years and older with acute hepatic porphyria who experienced at least two attacks that required hospitalization, urgent care or intravenous hemin in the past 6 months, Thapar reported. More than 75% of patients were attack-free at 21 to 24 months.
Of 93 patients who entered the open-label extension period, data at 36 months showed givosiran treatment induced sustained reduction in median urinary 5-aminolevulinic acid to near-normal levels and decreases in porphobilinogen levels by more than 90%. Continued treatment led to sustained reduction in attacks and hemin use in both arms.
During the open-label extension period, the proportion of patients who experienced no attacks per 3-month interval improved, with 86% of patients in the continuous treatment group and 92% of patients in the placebo crossover group attack-free at 33 to 36 months. Similarly, 88% of continuous-treatment patients and 90% of placebo-crossover patients reported no hemin use in the same time period.
Thapar noted further improvements were observed in quality of life and activities of daily living during the open-label extension period. The most common treatment-related adverse events were injection site reactions, nausea and fatigue. Six patients discontinued treatment.
“Over 3 years the efficacy is maintained,” Thapar concluded. “It does improve the patient’s overall quality of life, their attack rates by approximately 90% and they continue to perform well in normal life.”
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Thapar M, et al. Abstract OS075. Presented at: International Liver Congress; June 22-26, 2022; London (hybrid meeting).
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