S1169 Twelve-Month Interim Analysis of Efficacy and Safety of Givosiran, an Investigational RNAi Therapeutic for Acute Hepatic Porphyria, in the ENVISION Open Label Extension
Bibliographic record
Abstract
INTRODUCTION: Acute hepatic porphyria (AHP) is a family of rare genetic diseases due to enzyme defects in hepatic heme biosynthesis. Induction of 5-aminolevulinic acid synthase 1 (ALAS1), the rate-limiting step in heme biosynthesis, can lead to accumulation of toxic heme intermediates 5-aminolevulinic acid (ALA) and porphobilinogen (PBG), causing neurovisceral attacks and chronic manifestations. Givosiran, an investigational RNAi therapeutic, targets liver ALAS1 to reduce ALA/PBG and ameliorate attacks and clinical manifestations. METHODS: ENVISION (NCT03338816) is an ongoing Phase 3 global, multicenter, randomized, placebo-controlled trial, evaluating the efficacy and safety of subcutaneous monthly doses of 2.5 mg/kg givosiran in AHP patients in a 6-month double-blind (DB) period and an open label extension (OLE) period (up to 30 months). During the OLE, patients received either 2.5 mg/kg or 1.25 mg/kg monthly givosiran. Outcome measures included composite annualized attack rate (AAR) requiring hospitalization, urgent care, or IV-hemin at home, ALA/PBG levels, hemin use, daily worst symptoms, and quality of life (QoL). Analyses were descriptive. RESULTS: As of July 23, 2019, 93 patients entered the OLE: 56 (placebo/givosiran = 29; givosiran/givosiran = 27) received 2.5 mg/kg monthly givosiran, and 37 (placebo/givosiran = 17; givosiran/givosiran = 20) received 1.25 mg/kg. In givosiran patients (both doses), median AAR was 1.1 (range: 0–20.5) through Month 12. In placebo patients who crossed over to givosiran in the OLE, median AAR (DB = 10.65; OLE = 1.81) and proportion of attack-free patients (DB = 17.4%; OLE = 42.2%) were similar to the givosiran group in the DB period (median AAR = 1.04; attack free patients = 48.9%). In addition, sustained lowering of ALA/PBG in the OLE was accompanied by reductions in hemin use, daily worst pain and analgesic use, and improvements in QoL. Among patients on givosiran through Month 12, 62% had ≥1 drug-related adverse event (AE) and 3% had ≥1 drug-related serious AE. There were no new AEs leading to discontinuation and no deaths. No new safety concerns occurred in the OLE. There was a trend toward increased efficacy with the 2.5 mg/kg dose compared to 1.25 mg/kg dose, and safety was acceptable at both doses. CONCLUSION: In an ongoing Phase 3 study, givosiran 2.5 mg/kg monthly demonstrated maintenance or enhancement of clinical efficacy and an acceptable safety profile consistent with that observed in the 6-month DB period.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.009 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".