Planté‐Bordeneuve, Violaine

Importance There is a lack of long-term efficacy and safety data on hereditary transthyretin amyloidosis with polyneuropathy (hATTR-PN) and on RNA interference (RNAi) therapeutics in general. This study presents the longest-term data to date on patisiran for hATTR-PN. Objective To present the long-term efficacy and safety of patisiran in adults with hATTR-PN. Design, Setting, and Participants This global open-label extension (OLE) of the APOLLO randomized clinical trial and phase 2 OLE study enrolled patients from 43 hospitals or clinical centers across 19 countries between July 2015 and August 2017, with follow-up until November 2022. Of 212 eligible patients with hATTR who completed the phase 3 APOLLO or phase 2 OLE parent studies, 211 enrolled in and 138 completed the global OLE. Intervention Patisiran, 0.3 mg/kg, intravenously once every 3 weeks for up to 5 years. Main Outcomes and Measures Outcomes evaluated at year 5 of the global OLE included disability (polyneuropathy disability [PND] score); polyneuropathy severity (Neuropathy Impairment Score [NIS]), nutritional status (modified body mass index [mBMI]), quality of life (Norfolk Quality of Life–Diabetic Neuropathy [Norfolk QOL-DN]), and Rasch-Built Overall Disability Scale (R-ODS), with no statistical hierarchy. Safety, survival probability, and mortality were also assessed. Results At the global OLE baseline, the mean (SD) age was 61.3 (12.3) years, and 156 patients (73.9%) were male. In 138 patients completing the study, PND scores remained stable or improved in 89 patients (65.0%), NISs showed a mean (SD) change of 10.9 (14.7), and mean (SD) mBMI (calculated as weight in kilograms divided by height in meters squared times serum albumin in grams per liter) increased by 46.4 (120.7) over 5 years from baseline. Norfolk QOL-DN and R-ODS scores showed mean (SD) changes of 4.1 (16.7) and –3.7 (6.2), respectively. Adverse events (AEs) leading to study withdrawal occurred in 47 patients (22.3%). Infusion-related reactions were the most common treatment-related AE (n = 34 [16.1%]). Overall, 41 patients (19.4%) died during the study. Patisiran treatment in the parent study and low familial amyloid polyneuropathy score at parent study baseline were associated with significantly improved survival. Conclusions and Relevance In the longest study of an RNAi therapeutic for any disease, patisiran treatment resulted in modest changes for patients with hATTR-PN with an acceptable safety profile. These results highlight the importance of initiating early treatment for hATTR and the potential of RNAi therapeutics in medicine. Trial Registration ClinicalTrials.gov Identifier: NCT02510261

Background and purposeHereditary transthyretin (hATTR) amyloidosis causes progressive polyneuropathy resulting from transthyretin (TTR) amyloid deposition throughout the body, including the peripheral nerves. The efficacy and safety of inotersen, an antisense oligonucleotide inhibitor of TTR protein production, were demonstrated in the pivotal NEURO‐TTR study in patients with hATTR polyneuropathy. Here, the long‐term efficacy and safety of inotersen are assessed in an ongoing open‐label extension (OLE) study.MethodsPatients who completed NEURO‐TTR were eligible to enroll in the OLE (NCT02175004). Efficacy assessments included the modified Neuropathy Impairment Score plus seven neurophysiological tests composite score (mNIS + 7), the Norfolk Quality of Life – Diabetic Neuropathy (Norfolk QOL‐DN) questionnaire total score and the Short‐Form 36 Health Survey (SF‐36) Physical Component Summary (PCS) score. Safety and tolerability were also assessed.ResultsOverall, 97% (135/139) of patients who completed NEURO‐TTR enrolled in the OLE. Patients who received inotersen for 39 cumulative months in NEURO‐TTR and the OLE continued to show benefit; patients who switched from placebo to inotersen in the OLE demonstrated improvement or stabilization of neurological disease progression by mNIS + 7, Norfolk QOL‐DN and SF‐36 PCS. No new safety concerns were identified. There was no evidence of increased risk for grade 4 thrombocytopenia or severe renal events with increased duration of inotersen exposure.ConclusionInotersen slowed disease progression and reduced deterioration of quality of life in patients with hATTR polyneuropathy. Early treatment with inotersen resulted in greater long‐term disease stabilization than delayed initiation. Routine platelet and renal safety monitoring were effective; no new safety signals were observed.

Abstract Background: Hereditary transthyretin amyloidosis (hATTR) is a rare, progressive, and fatal disease caused by the buildup of transthyretin-derived amyloid protein in major organs, predominantly affecting the peripheral nerves and heart. Inotersen, a second-generation antisense oligonucleotide targeting TTR mRNA, has shown efficacy and safety in patients with hATTR in a randomized, double-blind, placebo-controlled, phase 3 study, NEURO-TTR (ClinicalTrials.gov, NCT01737398; Benson NEJM 2018). Patients with hATTR amyloidosis who completed the NEURO-TTR study were eligible to receive inotersen for up to 5 years in a phase 3 open-label extension study (ClinicalTrials.gov, NCT02175004). Methods: In NEURO-TTR, patients were randomized 2:1 to receive inotersen (300-mg weekly subcutaneous doses) or placebo. In the open-label extension, patients continued inotersen (inotersen-inotersen) or switched from placebo to inotersen (placebo-inotersen). Evaluations included modified Neuropathy Impairment Score +7 neurophysiologic tests composite score (mNIS+7; higher scores indicate worse neuropathy), Norfolk Quality of Life-Diabetic Neuropathy questionnaire total score (Norfolk QoL-DN; higher scores indicate worse QoL), and adverse events (AEs). Cardiomyopathy (CM) was defined by a diagnosis of hATTR-CM at trial entry or by an interventricular wall thickness of 13 mm or more on transthoracic echocardiography at baseline, as ascertained by a central reader, or no known history of persistent hypertension (systolic blood pressure, ≥150 mm Hg) within 12 months before screening. Results : In the placebo-controlled, double-blind, phase 3 NEURO-TTR study, 112/172 patients were randomized and received inotersen. At baseline, patients were predominantly white (91.9%) males (68.6%) with a mean age of 59.2 years. A total of 67.4% had stage I (ambulatory) and 32.6% had stage II (ambulatory with assistance) disease. Inotersen-treated patients who had stage II disease had a longer duration of disease from diagnosis (40.9 vs 24.8 months, respectively) and from onset (72.6 vs 63.2 months, respectively) of hATTR polyneuropathy symptoms compared with placebo-treated patients who had stage II disease, indicating more advanced disease. A higher proportion of inotersen-treated patients had CM at baseline (67% vs 55%, respectively), and more severe CM, measured by higher NT-proBNP levels and longer duration of disease from hATTR-CM symptom onset, compared with placebo-treated patients. In the phase 3 open-label extension study as of Sept 15, 2017, 134 of 135 patients enrolled received ≥1 dose of inotersen. The mean age was 60.4 years and most patients were male (69.4%). Extended dosing with inotersen up to 27 months continued to improve mNIS+7 and Norfolk QoL-DN in the open-label extension compared to placebo-treated patients at week 66 in the double-blind NEURO-TTR study; mean changes from open-label extension baseline to open-label extension week 52 in the inotersen-inotersen group were 5.1 points for mNIS+7 (vs 25.5 for placebo-treated patients in the double-blind NEURO-TTR study) and 3.9 points for Norfolk QoL-DN (vs 10.7 for placebo-treated patients in the double-blind NEURO-TTR study). Initiation of inotersen in placebo-treated patients (placebo-inotersen) resulted in improvement in mNIS+7 and Norfolk QoL-DN by week 26. Few patients discontinued treatment because of AEs (inotersen-inotersen, 9%; placebo-inotersen, 4%). The rate of treatment-related serious AEs was low in both treatment groups (2% each). There was no evidence of increased risk for grade 4 thrombocytopenia or severe renal events with increased duration of exposure. We will present 2-year follow-up results from the open-label extension study. Conclusions: Results of the open-label extension show continued benefit, measured by mNIS+7 and Norfolk QoL-DN, and confirmed that earlier initiation of treatment is important for optimal clinical outcomes. No new safety concerns were identified. Results from the longer-term follow-up for the open-label extension will further elucidate how inotersen may benefit patients with hATTR amyloidosis. Disclosures Brannagan: Alnylam: Honoraria, Other: Investigator, Speakers Bureau; Ionis: Other: Investigator. Wang:Ionis: Other: Investigator, Speakers Bureau. Coelho:Prothena: Consultancy, Honoraria; Ionis: Consultancy, Other: Investigator; Alnylam: Consultancy, Honoraria, Other: Investigator; Pfizer: Consultancy, Honoraria, Other: Investigator. Waddington Cruz:Ionis: Honoraria; Genzyme/Sanofi: Honoraria; Pfizer: Honoraria. Polydefkis:Pfizer: Honoraria; Alnylam: Honoraria. Dyck:Ionis: Consultancy; Alnylam: Consultancy. Plante-Bordeneuve:Alnylam: Consultancy; Pfizer: Consultancy, Other: reimbursement for travel and meeting; Ionis: Other: reimbursement for travel and meeting. Berk:Ionis: Honoraria, Other: Investigator; Alnylam: Honoraria, Other: Investigator; Pfizer: Other: Investigator. Barroso:Pfizer: Consultancy, Honoraria, Other: Thaos registry, Speakers Bureau; Alnylam: Honoraria, Other: Investigator. Conceição:Alnylam: Consultancy, Honoraria, Speakers Bureau; Pfizer: Consultancy, Honoraria, Speakers Bureau; Sanofi: Honoraria, Speakers Bureau. Hughes:Ionis: Employment. Kwoh:Ionis: Employment. Jung:Ionis: Employment. Guthrie:Akcea: Employment. Pollock:Akcea: Employment. Benson:Ionis: Other: Investigator, Research Funding. Gertz:janssen: Consultancy; Teva: Consultancy; spectrum: Consultancy, Honoraria; Alnylam: Honoraria; Ionis: Honoraria; Amgen: Consultancy; annexon: Consultancy; Prothena: Honoraria; Research to Practice: Consultancy; Apellis: Consultancy; celgene: Consultancy; Abbvie: Consultancy; Medscape: Consultancy; Physicians Education Resource: Consultancy.