Pharmacotherapeutic group: Other Nervous System Drugs; ATC code: N07XX18
Mechanism of actionAmvuttra contains vutrisiran, a chemically stabilized double-stranded small interfering ribonucleicacid (siRNA) that specifically targets variant and/or wild-type transthyretin (TTR) messenger RNA(mRNA) and is covalently linked to a ligand containing three N - acetylgalactosamine (GalNAc)residues to enable delivery of the siRNA to hepatocytes.
Through a natural process called RNA interference (RNAi), vutrisiran causes the catalytic degradationof TTR mRNA in the liver, resulting in the reduction of serum levels of variant and wild-typeamyloidogenic TTR protein thus reducing the deposition of TTR amyloid in tissues.
Pharmacodynamic effectsIn HELIOS-A, mean serum TTR was rapidly reduced as early as Day 22, with mean near to steadystate TTR reduction of 73% by Week 6. With repeat dosing of 25 mg once every 3 months, meanreductions of serum TTR after 9 and 18 months of treatment were 83% and 88%, respectively. Similar
TTR reductions were observed regardless of genotype (V30M or non-V30M), prior TTR stabiliseruse, weight, sex, age, or race.
In HELIOS-B, the mean serum TTR reduction profile was consistent with that observed in
HELIOS-A, and similar across all subgroups studied (age, sex, race, body weight, anti-drug antibody[ADA] status, ATTR disease type [wild-type or hereditary], NYHA class, and baseline tafamidis use).
Serum TTR is a carrier of retinol binding protein 4, which is the principal carrier of vitamin A in theblood. In HELIOS-A, Amvuttra decreased serum vitamin A levels with mean steady state peak andtrough reductions of 70% and 63%, respectively (see sections 4.4 and 4.5). In HELIOS-B, serumvitamin A reductions were consistent with those observed in HELIOS-A.
In HELIOS-B, NT-proBNP and Troponin I, cardiac biomarkers associated with heart failure,demonstrated relative stability in Amvuttra-treated patients for median change from baseline through
Month 30 in the overall population (NT-proBNP: 9% increase; Troponin I: 10% decrease) while levelsin placebo patients demonstrated worsening (NT-proBNP: 52% increase; Troponin I: 22% increase).
Consistent trends were observed in the monotherapy population.
In HELIOS-B, centrally-assessed echocardiograms showed reduction relative to placebo favouring
Amvuttra in LV wall thickness (LS mean difference: -0.4 mm [95% CI -0.8, -0.0]) and longitudinalstrain (LS mean difference: -1.23% [95% CI -1.73, -0.73]) in the overall population. Results in themonotherapy population were consistent.
Clinical efficacy and safetyhATTR amyloidosis with polyneuropathy
The efficacy of Amvuttra was studied in a global, randomised, open-label clinical study (HELIOS-A)in adult patients with hATTR-PN. Patients were randomised 3:1 to receive 25 mg of Amvuttra(N=122) subcutaneously once every 3 months, or 0.3 mg/kg patisiran (N=42) intravenously onceevery 3 weeks. The treatment period of the study was conducted over 18 months with two analyses at
Month 9 and at Month 18. Ninety-seven percent (97%) of Amvuttra-treated patients completed at least18 months of the assigned treatments (vutrisiran or patisiran). Efficacy assessments were based on acomparison of the vutrisiran arm of the study with an external placebo group (placebo arm of the
APOLLO Phase 3 study) comprised of a similar population of patients with hATTR-PN. Assessmentof non-inferiority of serum TTR reduction was based on comparison of the vutrisiran arm to thewithin-study patisiran arm.
Of the patients who received Amvuttra, the median patient age at baseline was 60 years (range 34 to80 years), 38% were ≥ 65 years old, and 65% of patients were male. Twenty-two (22) different TTRvariants were represented: V30M (44%), T60A (13%), E89Q (8%), A97S (6%), S50R (4%), V122I(3%), L58H (3%), and Other (18%). Twenty percent (20%) of patients had the V30M genotype andearly onset of symptoms (< 50 years old). At baseline, 69% of patients had stage 1 disease(unimpaired ambulation; mild sensory, motor, and autonomic neuropathy in the lower limbs), and 31%had stage 2 disease (assistance with ambulation required; moderate impairment of the lower limbs,upper limbs, and trunk). There were no patients with stage 3 disease. Sixty-one percent (61%) ofpatients had prior treatment with TTR tetramer stabilisers. According to the New York Heart
Association (NYHA) classification of heart failure, 9% of patients had class I and 35% had class II.
Thirty-three percent (33%) of patients met pre-defined criteria for cardiac involvement (baseline LVwall thickness ≥ 13 mm with no history of hypertension or aortic valve disease).
The primary efficacy endpoint was the change from baseline to Month 18 in modified Neuropathy
Impairment Score +7 (mNIS+7). This endpoint is a composite measure of motor, sensory, andautonomic neuropathy including assessments of motor strength, reflexes, quantitative sensory testing,nerve conduction studies, and postural blood pressure, with the score ranging from 0 to 304 points,where an increasing score indicates worsening impairment.
The change from baseline to Month 18 in Norfolk Quality of Life-Diabetic Neuropathy (QoL-DN)total score was assessed as a secondary endpoint. The Norfolk QoL-DN questionnaire (patient-reported) includes domains relating to small fibre, large fibre, and autonomic nerve function,symptoms of polyneuropathy, and activities of daily living, with the total score ranging from -4 to 136,where increasing score indicates worsening quality of life.
Other secondary endpoints included gait speed (10-meter walk test), nutritional status (mBMI), andpatient-reported ability to perform activities of daily living and social participation (Rasch-Built
Overall Disability Scale [R-ODS]).
Treatment with Amvuttra in the HELIOS-A study demonstrated statistically significant improvementsin all endpoints (Table 2 and Figure 1) measured from baseline to Month 9 and 18, compared to theexternal placebo group of the APOLLO study (all p < 0.0001).
The time-averaged trough TTR percent reduction through Month 18 was 84.7% for vutrisiran and80.6% for patisiran. The percent reduction in serum TTR levels in the vutrisiran arm was non-inferior(according to predefined criteria) to the within-study patisiran arm through Month 18 with a mediandifference of 5.3% (95% CI 1.2%, 9.3%).
Table 2: Summary of clinical efficacy results from the HELIOS-A study
Baseline, Mean (SD) Change from Baseline, Amvuttra -Placebob
Endpointa LS Mean (SEM) Treatment
Amvuttra Placebob b Difference, p-value
N=122 N=77 Amvuttra Placebo LS Mean (95% CI)
Month 9mNIS+7c 60.6 (36.0) 74.6 (37.0) -2.2 (1.4) 14.8 (2.0) -17.0(-21.8, -12.2) p<0.0001
Norfolk
QoL-DNc 47.1 (26.3) 55.5 (24.3) -3.3 (1.7) 12.9 (2.2) -16.2(-21.7, -10.8) p<0.000110-meterwalk test 1.01 (0.39) 0.79 (0.32) 0 (0.02) -0.13 (0.03) 0.13(m/sec)d (0.07, 0.19) p<0.0001
Month 18mNIS+7c 60.6 (36.0) 74.6 (37.0) -0.5 (1.6) 28.1 (2.3) -28.5(-34.0, -23.1) p<0.0001
Norfolk -21.0
QoL-DNc 47.1 (26.3) 55.5 (24.3) -1.2 (1.8) 19.8 (2.6) (-27.1, -14.9) p<0.000110-meterwalk test 1.01 (0.39) 0.79 (0.32) -0.02 0.24(m/sec)d (0.03) -0.26 (0.04) (0.15, 0.33) p<0.0001mBMIe 1057.5 989.9 25.0 (9.5) -115.7 (13.4) 140.7(233.8) (214.2) (108.4, 172.9) p<0.0001
R-ODSf 34.1 (11.0) 29.8 (10.8) -1.5 (0.6) -9.9 (0.8) 8.4(6.5, 10.4) p<0.0001
Abbreviations: CI=confidence interval; LS mean=least squares mean; mBMI=modified body mass index; mNIS=modified
Neuropathy Impairment Score; QoL-DN=Quality of Life - Diabetic Neuropathy; SD=standard deviation; SEM=standarderror of the meana All Month 9 endpoints analysed using the analysis of covariance (ANCOVA) with multiple imputation (MI) method and all
Month 18 analysed using the mixed-effects model for repeated measures (MMRM)b External placebo group from APOLLO randomised controlled studyc A lower number indicates less impairment/fewer symptomsd A higher number indicates less disability/less impairmente mBMI: body mass index (BMI; kg/m2) multiplied by serum albumin (g/L); a higher number indicates better nutritionalstatus.f A higher number indicates less disability/less impairment.
Figure 1: Change from Baseline in mNIS+7 (Month 9 and Month 18)28.1 (2.3)
Placeboa14.8 (2.0) -28.5(95% Cl: -34.0, -23.1)p = 6.5x10-20
- 17.0(95% Cl: -21.8, -12.2)p = 3.5x10-12
Amvuttra
- 0.5 (1.6)
- 2.2 (1.4)
Baseline Month 9 Month 18
N evaluable
Placeboa
Amvuttr
A decrease in mNIS+7 indicates improvement∆ indicates between-group treatment difference, shown as the LS mean difference (95% CI) for AMVUTTRA -externalplacebo
All Month 9 endpoints analysed using the analysis of covariance (ANCOVA) with multiple imputation (MI) method and all
Month 18 analysed using the mixed-effects model for repeated measures (MMRM)a External placebo group from APOLLO randomised controlled study
Patients receiving Amvuttra experienced similar benefit relative to placebo in mNIS+7 and Norfolk
QoL-DN total score at Month 9 and Month 18 across all subgroups including age, sex, race, region,
NIS score, V30M genotype status, prior TTR stabiliser use, disease stage, and patients with or withoutpre-defined criteria for cardiac involvement.
The N-terminal prohormone-B-type natriuretic peptide (NT-proBNP) is a prognostic biomarker ofcardiac dysfunction. NT-proBNP- baseline values (geometric mean) were 273 ng/L and 531 ng/L in
Amvuttra-treated and placebo-treated patients, respectively. At Month 18, the geometric mean
NT-proBNP levels decreased by 6% in Amvuttra patients, while there was a 96% increase in placebopatients.
Centrally-assessed echocardiograms showed changes in LV wall thickness (LS mean difference: -0.18mm [95% CI -0.74, 0.38]) and longitudinal strain (LS mean difference: -0.4% [95% CI -1.2, 0.4]) with
Amvuttra treatment relative to placebo.
wtATTR or hATTR amyloidosis with cardiomyopathy
The efficacy of Amvuttra was demonstrated in a global, randomised, double-blind, placebo-controlledclinical study (HELIOS-B) in adult patients with ATTR-CM. Patients were randomized 1:1 to receive25 mg of Amvuttra subcutaneously once every 3 months, or matching placebo. At baseline, 40% ofpatients were receiving treatment with tafamidis. Treatment assignment was stratified by baselinetafamidis use, ATTR disease type (wtATTR or hATTR amyloidosis), and by baseline severity ofdisease and age (NYHA Class I or II and age < 75 years versus all other).
Of the patients who received Amvuttra, at baseline, the median patient age was 77 years (range 45 to85 years) and 92% were male. Eighty five percent (85%) of patients were Caucasian, 7% were Blackor African American, 6% were Asian. Eighty nine percent (89%) of patients had wtATTRamyloidosis and 11% had hATTR amyloidosis. According to the NYHA classification of heart failure(HF), 15% of patients had Class I, 77% had Class II, and 8% had Class III and were NAC ATTR
LS Mean (SE) Change in mNIS+7disease stage 1 or 2. Patient demographics and baseline disease characteristics were similar betweenthe treatment groups.
The primary efficacy endpoint was the composite outcome of all-cause mortality and recurrent CVevents (CV hospitalisations and urgent heart failure [UHF] visits) during the double-blind treatmentperiod of up to 36 months, evaluated in the overall population and in the monotherapy population(defined as patients not receiving tafamidis at study baseline).
Amvuttra led to significant reductions in the risk of all-cause mortality and recurrent CV eventscompared to placebo in the overall and monotherapy populations of 28.2% and 32.8%, respectively(Table 3). Approximately 77% of all deaths in HELIOS-B were CV-related. The rate of both CVdeaths and non-CV deaths was lower in Amvuttra-treated patients compared to placebo. Of the totalnumber of CV events, 87.9% were CV hospitalisations, and 12.1% were UHF visits. A Kaplan-Meiercurve illustrating time to first CV event or all-cause mortality is presented in Figure 2.
Both components of the primary composite endpoint individually contributed to the treatment effect inthe overall population and monotherapy population (Table 3).
In the secondary endpoint analysis of all-cause mortality including data up to Month 42, incorporatingthe double-blind period and up to an additional 6 months of survival data for all patients, Amvuttra ledto a 35.5% reduction in the risk of death relative to placebo in the overall population (hazard ratio:0.645; 95% CI: 0.463, 0.898; p=0.0098), and to a 34.5% reduction in the monotherapy population(hazard ratio: 0.655; 95% CI: 0.440, 0.973; p=0.0454).
Table 3: Primary composite endpoint and its individual components in HELIOS-B
Endpoint Overall population Monotherapy population
Amvuttra Placebo Amvuttra Placebo(N=326) (N=328) (N=196) (N=199)
Primary composite Hazard Ratio (95% CI)b 0.718 (0.555, 0.929) 0.672 (0.487, 0.929)endpointa p-valueb 0.0118 0.0162
Components of the Primary Composite Endpoint
All-causemortality Hazard Ratio (95% CI)c 0.694 (0.490, 0.982) 0.705 (0.467, 1.064)
CV hospitalisationsand UHF visits Relative Rate Ratio (95% CI)d 0.733 (0.610, 0.882) 0.676 (0.533, 0.857)
Abbreviations: CI=confidence interval; CV=cardiovascular; UHF=urgent heart failure
Heart transplantation and left ventricular assist device placement are treated as death. Deaths after study discontinuation areincluded in the all-cause mortality component analysis.
a Primary composite endpoint defined as: composite outcome of all-cause mortality and recurrent CV events. Primary analysisincluded at least 33 months (and up to 36 months) follow-up on all patients.b Hazard Ratio (95% CI) and p-value are based on a modified Andersen-Gill model.c Hazard Ratio (95% CI) is based on a Cox proportional hazard model.d Relative rate ratio (95% CI) is based on a Poisson regression model.
Figure 2: Time to First CV Event or All-Cause Mortality (Overall population)60 AMVUTTRA50 Placebo0 HR:0.716 (0.566, 0.905), p-value:0.00620 3 6 9 12 15 18 21 24 27 30 33 36 39
Month
No. at Risk (Cumulative No. of Events)
Placebo 328 (0) 317 (11) 295 (31) 270 (53) 253 (70) 237 (84) 221 (96) 210 (105) 199 (115) 183 (131) 172 (142) 155 (154) 52 (159) 0 (159)
AMVUTTRA 326 (0) 306 (19) 294 (30) 284 (39) 271 (50) 254 (65) 247 (72) 237 (81) 227 (90) 216 (101) 206 (110) 185 (118) 62 (125) 0 (125)
Abbreviation: CI=confidence interval; CV=cardiovascular; HR = hazard ratio.
Heart transplantation and left ventricular assist device placement are treated as death. Kaplan-Meier curves are adjusted for baseline diseasecharacteristics using the inverse probability of treatment weighting method. HR and 95% CI are based on a Cox proportional hazard model,and p-value is based on log-rank test.
Results from the subgroup analysis for the primary composite endpoint favoured Amvuttra across allprespecified subgroups in the overall population and the monotherapy population. In the subgroup ofpatients on background tafamidis, Amvuttra led to a 21.5% numerical reduction in the risk of all-causemortality and recurrent CV events relative to placebo (hazard ratio: 0.785; 95% CI: 0.511, 1.207)(Figure 3).
Probability of CV Events or Mortality Free (%)
Figure 3: Subgroup Analyses of the Primary Composite Endpoint (Overall Population)
HR 95% CI
Overall (N=654) 0.718 (0.555, 0.929)
Tafamidis use at baseline
No (N=395) 0.672 (0.487, 0.929)
Yes (N=259) 0.785 (0.511, 1.207)
Age at baseline<75 (N=257) 0.545 (0.348, 0.854)≥75 (N=397) 0.806 (0.584, 1.114)
ATTR disease typehATTR (N=76) 0.922 (0.494, 1.724)wtATTR (N=578) 0.674 (0.506, 0.898)
NYHA class at baseline
I/II (N=592) 0.727 (0.552, 0.958)
III (N=62) 0.681 (0.330, 1.406)
NT-pro-BNP at baseline≤2000 (N=342) 0.525 (0.349, 0.788)>2000 (N=312) 0.798 (0.562, 1.133)0.5 1 2
Favours Amvuttra Favours Placebo
Abbreviations: ATTR = transthyretin amyloidosis; CI = confidence interval; hATTR = hereditary transthyretin amyloidosis; HR = hazardratio; NT-proBNP = N-terminal prohormone of B-type natriuretic peptide; NYHA = New York Heart Association; wtATTR = wild-typetransthyretin amyloidosis.
HR and 95% CI are based on modified Andersen-Gill model analyses.
The treatment effects of Amvuttra on functional capacity, patient-reported health status and quality oflife, and heart failure symptom severity were assessed by the change from baseline to Month 30 in6-Minute Walk Test (6-MWT), the Kansas City Cardiomyopathy Questionnaire-Overall Summary(KCCQ-OS) score and NYHA class, respectively. The KCCQ-OS is composed of four domainsincluding Total Symptoms (Symptom Frequency and Symptom Burden), Physical Limitation, Qualityof Life, and Social Limitation. The Overall Summary score and domain scores range from 0 to 100,with higher scores representing better health status.
A statistically significant treatment effect favouring Amvuttra was observed for 6-MWT distance,
KCCQ-OS score, and stable or improved NYHA class, in both the overall population andmonotherapy population (Table 4), with consistent results across all subgroups studied. The treatmenteffect on KCCQ-OS score was consistent across all four domain scores.
Table 4. Change from Baseline in 6-MWT distance, KCCQ-OS score and NYHA class at
Month 30
Overall population Monotherapy population
Amvuttra Placebo Amvuttra Placebo(N=326) (N=328) (N=196) (N=199)6-MWT (metres)
Baseline Mean (SD) 372 (104) 377 (96) 363 (103) 373 (98)
Change from baseline to
Month 30, LS Mean (SE)a -45 (5) -72 (5) -60 (7) -92 (6)
Treatment Difference from 26 (13, 40) 32 (14, 50)
Placebo, LS Mean (95% CI)p-valuea,b <0.0001 0.0005
KCCQ-OS (points)
Baseline Mean (SD) 73 (19) 72 (20) 70 (20) 70 (21)
Change from baseline to
Month 30, LS Mean (SE)a -10 (1) -15 (1) -11 (2) -19 (2)
Treatment Difference from 6 (2, 9) 9 (4, 13)
Placebo, LS Mean (95% CI)p-valuea,b 0.0008 0.0003
NYHA Class% of patients with stable orimproved NYHA class at 68 61 66 56
Month 30
Difference from Placebo, (%) 9 (1, 16) 13 (3, 22)(95% CI)cp-valuec 0.0217 0.0121
Abbreviations: 6-MWT = 6-minute walk test; KCCQ-OS = Kansas City Cardiomyopathy Questionnaire, LS = least squares;
CI = confidence interval; SD = Standard deviation; SE = Standard Error; NYHA = New York Heart Associationa For assessment missing because of death (including heart transplantation and left ventricular assist device placement), andinability to walk as the result of ATTR disease progression (applicable to 6-MWT only), data were imputed from resampling ofthe worst 10% of observed changes.
b Estimated from the MMRM (mixed-effect model repeated measures) model.c Based on Cochran-Mantel-Haenszel method.
Paediatric populationThe European Medicines Agency has waived the obligation to submit the results of studies withvutrisiran in all subsets of the paediatric population in hATTR amyloidosis (see section 4.2 forinformation on paediatric use).