Spinal Muscular Atrophy
Conditions
Keywords
gene therapy
Brief summary
To evaluate the safety and efficacy of intravenous onasemnogene abeparvovec-xioi in pre-symptomatic patients with SMA and 2 or 3 copies SMN2
Detailed description
Phase 3, open-label, single-arm study of a single, one-time dose of onasemnogene abeparvovec-xioi (gene replacement therapy) in patients with spinal muscular atrophy who meet enrollment criteria and are genetically defined by bi-allelic deletion of survival motor neuron 1 gene (SMN1) with 2 or 3 copies of survival motor neuron 2 gene (SMN2). Patients with SMN1 point mutations or the SMN2 gene modifier mutation (c.859G\>C) may enroll but will not be included in the efficacy analysis sets. The study includes a screening period, a gene replacement therapy period, and a follow-up period. During the screening period (Days -30 to -2), patients whose parent(s)/legal guardian(s) provide informed consent will undergo screening procedures to determine eligibility for study enrollment. Patients who meet the entry criteria will enter the in-patient gene replacement therapy period (Day -1 to Day 2). On Day -1, patients will be admitted to the hospital for pre-treatment baseline procedures. On Day 1, patients will receive a single, one-time intravenous (IV) infusion of onasemnogene abeparvovec-xioi, and will undergo in-patient safety monitoring for a minimum of 24 hours post infusion. Patients may be discharged 24 hours (48 hours in Japan) after the infusion, based on Investigator judgment. During the outpatient follow-up period (Days 3 to End of Study at 18 or 24 of age, dependent upon respective SMN2 copy number), patients will return at regularly scheduled intervals for efficacy and safety assessments until the End of Study when the patient reaches 18 months of age (SMN2 = 2) or 24 months of age (SMN2 = 3). After the End of Study visit, eligible patients will be invited to rollover into a long-term follow up study.
Interventions
BIOLOGICALonasemnogene abeparvovec-xioi
A non-replicating recombinant AAV9 containing the complimentary deoxyribonucleic acid (cDNA) of the human SMN gene under the control of the cytomegalovirus (CMV) enhancer/chicken-β-actin-hybrid promoter (CB). The AAV inverted terminal repeat (ITR) has been modified to promote intramolecular annealing of the transgene, thus forming a double-stranded transgene ready for transcription.
Sponsors
Novartis Gene Therapies
PRA Health Sciences
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
Open-label, single arm
Eligibility
Sex/Gender
ALL
Age
No minimum to 42 Days
Healthy volunteers
No
Inclusion criteria
* Age ≤6 weeks (≤42 days) at time of dose * Ability to tolerate thin liquids as demonstrated through a formal bedside swallowing test * Compound muscle action potential (CMAP) ≥2mV at Baseline; centralized review of CMAP data will be conducted * Gestational age of 35 to 42 weeks * Parent(s)/legal guardian(s) willing and able to complete the informed consent process and comply with study procedures and visit schedule * Patients with pre-symptomatic SMA Type 1 as determined by the following features: a. 2 copies of SMN2 (n ≥14) * Patients with pre-symptomatic SMA Type 2 as determined by the following features: 1. 3 copies of SMN2 (n ≥12)
Exclusion criteria
* Weight at screening visit \<2 kg * Hypoxemia (oxygen saturation \<96% awake or asleep without any supplemental oxygen or respiratory support) at the screening visit or for altitudes \>1000 m, oxygen saturation \<92% awake or asleep without any supplemental oxygen or respiratory support at the screening visit * Any clinical signs or symptoms at screening or immediately prior to dosing that are, in the opinion of the Investigator, strongly suggestive of SMA * Tracheostomy or current prophylactic use or requirement of noninvasive ventilatory support at any time and for any duration prior to screening or during the screening period * Patients with signs of aspiration/inability to tolerate nonthickened liquids based on a formal swallowing test performed as part of screening or patients receiving any non-oral feeding method * Clinically significant abnormal laboratory values (gamma-glutamyl transferase \[GGT\], Alanine transaminase \[ALT\], and aspartate aminotransferase \[AST\], or total bilirubin \> 2 × the upper limit of normal \[ULN\], creatinine ≥ 1.0 mg/dL, hemoglobin \[Hgb\] \< 8 or \> 18 g/dL; white blood cell \[WBC\] \> 20,000 per cmm) prior to gene replacement therapy. Patients with an elevated bilirubin level that is unequivocally the result of neonatal jaundice shall not be excluded * Treatment with an investigational or commercial product, including nusinersen, given for the treatment of SMA. This includes any history of gene therapy, prior antisense oligonucleotide treatment, or cell transplantation. * Patients whose weight-for-age is below the third percentile based on World Health Organization (WHO) Child Growth Standards * Biological mother with active viral infection as determined by screening laboratory samples (includes human immunodeficiency virus \[HIV\] or positive serology for hepatitis B or C) • Biological mothers with clinical suspicion of Zika virus that meet Centers for Disease Control and Prevention (CDC) Zika virus epidemiological criteria including history of residence in or travel to a geographic region with active Zika transmission at the time of travel will be tested for Zika virus RNA. Positive results warrant confirmed negative Zika virus RNA testing in the patient prior to enrollment. * Serious nonrespiratory tract illness requiring systemic treatment and/or hospitalization within 2 Weeks prior to screening * Upper or lower respiratory infection requiring medical attention, medical intervention, or increase in supportive care of any manner within 4 Weeks prior to dosing * Severe nonpulmonary/respiratory tract infection within 4 Weeks before administration of gene replacement therapy or concomitant illness that, in the opinion of the Investigator or Sponsor medical monitor, creates unnecessary risks for gene replacement therapy such as: * Major renal or hepatic impairment * Known seizure disorder * Diabetes mellitus * Idiopathic hypocalciuria * Symptomatic cardiomyopathy * Known allergy or hypersensitivity to prednisolone or other glucocorticosteroids or their excipients * Previous, planned or expected major surgical procedure including scoliosis repair surgery/procedure during the study assessment period * Concomitant use of any of the following: drugs for treatment of myopathy or neuropathy, agents used to treat diabetes mellitus, or ongoing immunosuppressive therapy, plasmapheresis, immunomodulators such as adalimumab, immunosuppressive therapy within 4 Weeks prior to gene replacement therapy * AntiAAV9 antibody titer \>1:50 as determined by Enzyme-linked Immunosorbent Assay (ELISA) binding immunoassay • Should a potential patient demonstrate AntiAAV9 antibody titer \>1:50, he or she may receive retesting inside the 30-Day screening period and will be eligible to participate if the AntiAAV9 antibody titer upon retesting is ≤1:50, provided the \<6 Week age requirement at the time of dosing is still met * Biological mother involved with the care of the child refuses anti-AAV9 antibody testing prior to dosing
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Cohort 1: Number of Participants Who Achieved Sitting Alone for at Least 30 Seconds | From Day 1 up to 18 months of age visit | Defined by the Bayley Scales of Infant and Toddler Development (BSID) Gross Motor (GM) subtest performance criteria number 26, confirmed by video recording, as a participant who sits for at least 30 seconds without assistance from another person or object. The participant was allowed to use their upper extremities. |
| Cohort 2: Number of Participants Who Achieved Standing Alone for at Least 3 Seconds | From Day 1 up to 24 months of age visit | Defined by the BSID GM subtest performance criteria number 40, confirmed by video recording, as a participant who stands alone for at least 3 seconds unsupported. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Cohort 1: Event-free Survival at 14 Months of Age | From Day 1 up to 14 months of age | Event-free survival at 14 months of age was defined as the number of participants who did not die, did not require permanent ventilation and did not withdraw from the study by 14 months of age. |
| Cohort 1: Number of Participants Who Achieved the Ability to Maintain Weight at or Above the Third Percentile Without the Need for Non-Oral or Mechanical Feeding Support | From Day 1 up to 18 months of age | The ability to maintain weight at or above the third percentile without the need for non-oral or mechanical feeding support was defined by meeting the following criteria at each visit up to 18 months of age: * Did not receive nutrition through mechanical support (i.e., feeding tube) * Maintained weight (≥ third percentile for age and sex as defined by World Health Organization \[WHO\] guidelines) consistent with the participant's age at the assessment. |
| Cohort 2: Number of Participants Who Achieved the Ability to Walk Alone | From Day 1 up to 24 months of age visit | Defined by the BSID GM subtest performance criteria number 43, confirmed by video recording, as a participant who takes 5 coordinated independent steps. |
Countries
Australia, Belgium, Canada, Japan, United Kingdom, United States
Contacts
STUDY_DIRECTORNovartis Pharmaceuticals
Novartis Pharmaceuticals
Participant flow
Recruitment details
A total of 30 participants took part in the trial at 16 sites in the United States, the United Kingdom, Belgium, Canada, Australia and Japan between April 2018 and June 2021.
Pre-assignment details
A total of 44 participants were screened, of which 14 were screen failures and 30 were enrolled and received study drug. One participant had 4 copies of SMN2. This participant was excluded from all analysis populations and data is not reported due to privacy concerns.
Participants by arm
| Arm | Count |
|---|---|
| Cohort 1: Bi-allelic Deletions of SMN1 and 2 Copies of SMN2 Participants with bi-allelic deletions of survival of motor neuron 1 (SMN1) and 2 copies of SMN2 received a single dose of AVXS-101 administered as an intravenous (IV) infusion over 60 minutes at a dose of 1.1 × 10\^14 vg/kg (vector genome per kilogram) on Day 1 of the overall study. Participants also received daily doses of prophylactic oral prednisolone starting at a dose of 1-2 mg/kg/day from 1 day prior to AVXS-101 infusion until at least 30 days post-infusion at which point the prednisolone dose could be tapered downwards. At week 9, prednisolone could be discontinued. | 14 |
| Cohort 2: Bi-allelic Deletions of SMN1 and 3 Copies of SMN2 Participants with bi-allelic deletions of SMN1 and 3 copies of SMN2 received a single dose of AVXS-101 administered as an IV infusion over 60 minutes at a dose of 1.1 × 10\^14 vg/kg on Day 1 of the overall study. Participants also received daily doses of prophylactic oral prednisolone starting at a dose of 1-2 mg/kg/day from 1 day prior to AVXS-101 infusion until at least 30 days post-infusion at which point the prednisolone dose could be tapered downwards. At week 9, prednisolone could be discontinued | 15 |
| Total | 29 |
Baseline characteristics
| Characteristic | Cohort 1: Bi-allelic Deletions of SMN1 and 2 Copies of SMN2 | Cohort 2: Bi-allelic Deletions of SMN1 and 3 Copies of SMN2 | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 14 Participants | 15 Participants | 29 Participants |
| Age, Categorical >=65 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical Between 18 and 65 years | 0 Participants | 0 Participants | 0 Participants |
| Ethnicity (NIH/OMB) Hispanic or Latino | 4 Participants | 2 Participants | 6 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 10 Participants | 13 Participants | 23 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race/Ethnicity, Customized American Indian or Alaska Native | 0 Participants | 1 Participants | 1 Participants |
| Race/Ethnicity, Customized Asian | 2 Participants | 2 Participants | 4 Participants |
| Race/Ethnicity, Customized Black or African American | 1 Participants | 0 Participants | 1 Participants |
| Race/Ethnicity, Customized Other | 4 Participants | 2 Participants | 6 Participants |
| Race/Ethnicity, Customized White | 7 Participants | 10 Participants | 17 Participants |
| Sex: Female, Male Female | 10 Participants | 9 Participants | 19 Participants |
| Sex: Female, Male Male | 4 Participants | 6 Participants | 10 Participants |
| SMN2 gene modifier mutation (c.859G>C) Present | 0 Participants | 0 Participants | 0 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 14 | 0 / 15 |
| other Total, other adverse events | 14 / 14 | 15 / 15 |
| serious Total, serious adverse events | 5 / 14 | 3 / 15 |
Outcome results
Primary
Cohort 1: Number of Participants Who Achieved Sitting Alone for at Least 30 Seconds
Defined by the Bayley Scales of Infant and Toddler Development (BSID) Gross Motor (GM) subtest performance criteria number 26, confirmed by video recording, as a participant who sits for at least 30 seconds without assistance from another person or object. The participant was allowed to use their upper extremities.
Time frame: From Day 1 up to 18 months of age visit
Population: Intent-to-Treat (ITT) population (cohort 1) - All enrolled participants with bi-allelic SMN1 deletions and 2 copies of SMN2 without the SMN2 gene modifier mutation (c.859G\>C) who received AVXS-101.
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| Cohort 1: Bi-allelic Deletions of SMN1 and 2 Copies of SMN2 | Cohort 1: Number of Participants Who Achieved Sitting Alone for at Least 30 Seconds | 14 Participants |
Primary
Cohort 2: Number of Participants Who Achieved Standing Alone for at Least 3 Seconds
Defined by the BSID GM subtest performance criteria number 40, confirmed by video recording, as a participant who stands alone for at least 3 seconds unsupported.
Time frame: From Day 1 up to 24 months of age visit
Population: ITT population (cohort 2) - All enrolled participants with bi-allelic SMN1 deletions and 3 copies of SMN2 without the SMN2 gene modifier mutation (c.859G\>C) who received AVXS-101.
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| Cohort 1: Bi-allelic Deletions of SMN1 and 2 Copies of SMN2 | Cohort 2: Number of Participants Who Achieved Standing Alone for at Least 3 Seconds | 15 Participants |
p-value: <0.000195% CI: [50.95, 92.21]Fisher Exact
Secondary
Cohort 1: Event-free Survival at 14 Months of Age
Event-free survival at 14 months of age was defined as the number of participants who did not die, did not require permanent ventilation and did not withdraw from the study by 14 months of age.
Time frame: From Day 1 up to 14 months of age
Population: ITT population (cohort 1) - All enrolled participants with bi-allelic SMN1 deletions and 2 copies of SMN2 without the SMN2 gene modifier mutation (c.859G\>C) who received AVXS-101.
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| Cohort 1: Bi-allelic Deletions of SMN1 and 2 Copies of SMN2 | Cohort 1: Event-free Survival at 14 Months of Age | 14 Participants |
p-value: <0.000195% CI: [44.67, 91.61]Fisher Exact
Secondary
Cohort 1: Number of Participants Who Achieved the Ability to Maintain Weight at or Above the Third Percentile Without the Need for Non-Oral or Mechanical Feeding Support
The ability to maintain weight at or above the third percentile without the need for non-oral or mechanical feeding support was defined by meeting the following criteria at each visit up to 18 months of age: * Did not receive nutrition through mechanical support (i.e., feeding tube) * Maintained weight (≥ third percentile for age and sex as defined by World Health Organization \[WHO\] guidelines) consistent with the participant's age at the assessment.
Time frame: From Day 1 up to 18 months of age
Population: ITT population (cohort 1) - All enrolled participants with bi-allelic SMN1 deletions and 2 copies of SMN2 without the SMN2 gene modifier mutation (c.859G\>C) who received AVXS-101.
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| Cohort 1: Bi-allelic Deletions of SMN1 and 2 Copies of SMN2 | Cohort 1: Number of Participants Who Achieved the Ability to Maintain Weight at or Above the Third Percentile Without the Need for Non-Oral or Mechanical Feeding Support | 13 Participants |
Secondary
Cohort 2: Number of Participants Who Achieved the Ability to Walk Alone
Defined by the BSID GM subtest performance criteria number 43, confirmed by video recording, as a participant who takes 5 coordinated independent steps.
Time frame: From Day 1 up to 24 months of age visit
Population: ITT population (cohort 2) - All enrolled participants with bi-allelic SMN1 deletions and 3 copies of SMN2 without the SMN2 gene modifier mutation (c.859G\>C) who received AVXS-101.
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| Cohort 1: Bi-allelic Deletions of SMN1 and 2 Copies of SMN2 | Cohort 2: Number of Participants Who Achieved the Ability to Walk Alone | 14 Participants |
p-value: <0.000195% CI: [44.9, 90.11]Fisher Exact