Eplontersen for Hereditary Transthyretin Amyloidosis With Polyneuropathy
Authors: Coelho Teresa , Marques Wilson , Dasgupta Noel R. , Chao Chi-Chao , Parman Yeşim , França Marcondes Cavalcante , Guo Yuh-Cherng , Wixner Jonas , Ro Long-Sun , Calandra Cristian R. , Kowacs Pedro A. , Berk John L. , Obici Laura , Barroso Fabio A. , Weiler Markus , Conceição Isabel , Jung Shiangtung W. , Buchele Gustavo , Brambatti Michela , Chen Jersey , Hughes Steven G. , Schneider Eugene , Viney Nicholas J. , Masri Ahmad , Gertz Morie R. , Ando Yukio , Gillmore Julian D. , Khella Sami , Dyck P. James B. , Waddington Cruz Márcia ,   NEURO-TTRansform Investigators, Mazzeo Anna , Papagianni Aikaterini , Dimachkie Mazen , Zaganas Ioannis , Gane Edward , Luigetti Marco , Galan Davila Lucia , Mezei Michelle , Gonzalez Moreno Juan , Cintas Pascal , Pareyson Davide , Traub Rebecca , Khoury Julie , Estol Conrado , Needham Merrilee , Adams David , Polydefkis Michael , Brannagan Thomas , Bril Vera , Attarian Shahram , Rugiero Marcelo , Distad Barbara , Zamba Papanicolaou Eleni , Lin Kon-Ping , Benson Merrill , Scheinberg Morton 
Published: September 2023

Importance

Transthyretin gene silencing is an emerging treatment strategy for hereditary transthyretin (ATTRv) amyloidosis.

Objective

To evaluate eplontersen, an investigational ligand-conjugated antisense oligonucleotide, in ATTRv polyneuropathy.

Design, Setting, and Participants

NEURO-TTRansform was an open-label, single-group, phase 3 trial conducted at 40 sites across 15 countries (December 2019-April 2023) in 168 adults with Coutinho stage 1 or 2 ATTRv polyneuropathy, Neuropathy Impairment Score 10-130, and a documented TTR variant. Patients treated with placebo from NEURO-TTR (NCT01737398; March 2013–November 2017), an inotersen trial with similar eligibility criteria and end points, served as a historical placebo (“placebo”) group.

Interventions

Subcutaneous eplontersen (45 mg every 4 weeks; n = 144); a small reference group received subcutaneous inotersen (300 mg weekly; n = 24); subcutaneous placebo weekly (in NEURO-TTR; n = 60).

Main Outcomes and Measures

Primary efficacy end points at week 65/66 were changes from baseline in serum transthyretin concentration, modified Neuropathy Impairment Score +7 (mNIS+7) composite score (scoring range, –22.3 to 346.3; higher scores indicate poorer function), and Norfolk Quality of Life Questionnaire–Diabetic Neuropathy (Norfolk QoL-DN) total score (scoring range, –4 to 136; higher scores indicate poorer quality of life). Analyses of efficacy end points were based on a mixed-effects model with repeated measures adjusted by propensity score weights.

Results

Among 144 eplontersen-treated patients (mean age, 53.0 years; 69% male), 136 (94.4%) completed week-66 follow-up; among 60 placebo patients (mean age, 59.5 years; 68% male), 52 (86.7%) completed week-66 follow-up. At week 65, adjusted mean percentage reduction in serum transthyretin was −81.7% with eplontersen and −11.2% with placebo (difference, −70.4% [95% CI, −75.2% to −65.7%]; P &amp;lt; .001). Adjusted mean change from baseline to week 66 was lower (better) with eplontersen vs placebo for mNIS+7 composite score (0.3 vs 25.1; difference, −24.8 [95% CI, −31.0 to −18.6; P &amp;lt; .001) and for Norfolk QoL-DN (−5.5 vs 14.2; difference, −19.7 [95% CI, −25.6 to −13.8]; P &amp;lt; .001). Adverse events by week 66 that led to study drug discontinuation occurred in 6 patients (4%) in the eplontersen group vs 2 (3%) in the placebo group. Through week 66, there were 2 deaths in the eplontersen group consistent with known disease-related sequelae (cardiac arrhythmia; intracerebral hemorrhage); there were no deaths in the placebo group.

Conclusions and Relevance

In patients with ATTRv polyneuropathy, the eplontersen treatment group demonstrated changes consistent with significantly lowered serum transthyretin concentration, less neuropathy impairment, and better quality of life compared with a historical placebo.

Trial Registration

ClinicalTrials.gov Identifier: NCT04136184; EU Clinical Trials Register: EudraCT 2019-001698-10