Disease burden in patients with acute hepatic porphyria: experience from the phase 3 ENVISION study

Background: Acute hepatic porphyria (AHP) is a family of four rare genetic diseases, each involving deficiency in a hepatic heme biosynthetic enzyme. Resultant overproduction of the neurotoxic intermediates δ-aminolevulinic acid (ALA) and porphobilinogen (PBG) leads to disabling acute neurovisceral attacks and progressive neuropathy. We evaluated the AHP disease burden in patients aged ≥ 12 years in a post hoc analysis of the Phase 3, randomized, double-blind, placebo-controlled ENVISION trial of givosiran (NCT03338816), an RNA interference (RNAi) therapeutic that targets the enzyme ALAS1 to decrease ALA and PBG production. We analyzed baseline AHP severity via chronic symptoms between attacks, comorbidities, concomitant medications, hemin-associated complications, and quality of life (QOL) and evaluated givosiran (2.5 mg/kg monthly) in patients with and without prior hemin prophylaxis on number and severity of attacks and pain scores during and between attacks. Results: Participants (placebo, n = 46; givosiran, n = 48) included patients with low and high annualized attack rates (AARs; range 0–46). At baseline, patients reported chronic symptoms (52%), including nausea, fatigue, and pain; comorbidities, including neuropathy (38%) and psychiatric disorders (47%); concomitant medications, including chronic opioids (29%); hemin-associated complications (eg, iron overload); and poor QOL (low SF-12 and EuroQol visual analog scale scores). A linear relationship between time since diagnosis and AAR with placebo suggested worsening of disease over time without effective treatment. Givosiran reduced the number and severity of attacks, days with worst pain scores above baseline, and opioid use versus placebo. Conclusions: Patients with AHP, regardless of annualized attack rates, have considerable disease burden that may partly be alleviated with givosiran

Disease Burden in Patients with Acute Hepatic Porphyria: Experience from the Phase 3 ENVISION Study

BACKGROUND: Acute hepatic porphyria (AHP) is a family of four rare genetic diseases, each involving deficiency in a hepatic heme biosynthetic enzyme. Resultant overproduction of the neurotoxic intermediates δ-aminolevulinic acid (ALA) and porphobilinogen (PBG) leads to disabling acute neurovisceral attacks and progressive neuropathy. We evaluated the AHP disease burden in patients aged ≥ 12 years in a post hoc analysis of the Phase 3, randomized, double-blind, placebo-controlled ENVISION trial of givosiran (NCT03338816), an RNA interference (RNAi) therapeutic that targets the enzyme ALAS1 to decrease ALA and PBG production. We analyzed baseline AHP severity via chronic symptoms between attacks, comorbidities, concomitant medications, hemin-associated complications, and quality of life (QOL) and evaluated givosiran (2.5 mg/kg monthly) in patients with and without prior hemin prophylaxis on number and severity of attacks and pain scores during and between attacks. RESULTS: Participants (placebo, n = 46; givosiran, n = 48) included patients with low and high annualized attack rates (AARs; range 0-46). At baseline, patients reported chronic symptoms (52%), including nausea, fatigue, and pain; comorbidities, including neuropathy (38%) and psychiatric disorders (47%); concomitant medications, including chronic opioids (29%); hemin-associated complications (eg, iron overload); and poor QOL (low SF-12 and EuroQol visual analog scale scores). A linear relationship between time since diagnosis and AAR with placebo suggested worsening of disease over time without effective treatment. Givosiran reduced the number and severity of attacks, days with worst pain scores above baseline, and opioid use versus placebo. CONCLUSIONS: Patients with AHP, regardless of annualized attack rates, have considerable disease burden that may partly be alleviated with givosiran

Disease Burden in Patients With Acute Hepatic Porphyria: Experience From the Phase 3 ENVISION Study

Introduction: Acute hepatic porphyria (AHP) is a family of rare genetic diseases caused by defects in hepatic heme biosynthesis. Intravenous (IV) hemin is the standard of care for acute attacks and is at times used off label prophylactically, but can have acute (e.g. phlebitis) and chronic (e.g. iron overload) complications. The phase 3 ENVISION study (NCT03338816) showed givosiran reduced annualized attack rate (AAR) by 73% versus placebo in the double-blind (DB) period. Open-label extension data showed 85% of patients continuing givosiran were attack free at >15–18 months. Here we summarize data from ENVISION to assess the spectrum of disease burden associated with AHP. Methods: Patients (N=94) enrolled in ENVISION had experienced ≥2 attacks requiring hospitalization, urgent care, or IV hemin at home in the 6 months before the study. This analysis assessed AAR, daily worst pain (eDiary), comorbidity, concomitant medication, and quality of life (12-Item Short Form Health Survey [SF-12]). Results: Patients had severe disease burden at study entry, consistent with AHP burden shown in natural history studies. Patients reported a median of 4 (range, 0–46) attacks during the previous 6 months, despite 40% being on prophylactic hemin. Of all patients, 34% did not have attacks requiring hospitalization. Chronic symptoms, including pain, were experienced by 52% of patients daily or on most days between attacks. Baseline median SF-12 bodily pain score was 40 (scale 0–100), suggesting interference with normal functioning. Overall, 29% of patients used opioids daily or on most days between attacks. Most patients had comorbidities at baseline (47% had psychiatric disorders) (Table 1) and were taking concomitant medications. The median (Q1–Q3) ferritin level was 209 (48–719) µg/L (normal: female, 13–150 µg/L; male, 30–400 µg/L). A moderate linear correlation between longer time since AHP diagnosis and higher AAR with placebo during the 6-month DB period (r=0.403) suggests patients may experience worsening disease and complications over time. Givosiran provided clinical benefit, including reduction of daily worst pain and analgesics use. Conclusion: AHP disease burden, including the number of attacks, comorbidities, and concomitant medication use, has negative impacts on daily functioning. Earlier initiation of treatments, such as givosiran, that prevent attacks and reduce chronic manifestations of AHP may lead to improved prognosis for patients