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OpenTrials
Active, Not Recruiting

NCT Number: NCT05626855

Long-Term Safety & Efficacy of Apitegromab in Patients With SMA Who Completed Previous Trials of Apitegromab

The ONYX study is an Open-Label, Multicenter, Extension study that will evaluate the long-term safety and efficacy of Apitegromab in Patients with Type 2 and Type 3 SMA who have completed TOPAZ or SAPPHIRE.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients have completed the Phase 2 TOPAZ (Study SRK-015-002) trial or the Phase 3 SAPPHIRE (Study SRK-015-003) trial. (For TOPAZ, completed is defined as completion of Visit EC14 in Extension Period C or participating in TOPAZ at the time the trial is ended. For SAPPHIRE, completed is defined as completion of Visit 14 or participating in SAPPHIRE at the time the trial is ended)
  • Estimated life expectancy >2 years from the Baseline Visit (Day 1)
  • Able to receive study drug infusions and provide blood samples through the use of a peripheral IV or a long-term IV access device that the patient has placed for reasons independent from the trial
  • Able to adhere to the requirements of the protocol, including travel to the trial site and completing all trial procedures and trial visits
  • Females of childbearing potential must have a negative pregnancy test at the Baseline Visit and agree to use at least 1 highly effective method of contraception throughout the trial and for 20 weeks after the last dose of apitegromab

Exclusion criteria

  • Patient permanently discontinued study treatment during the feeder trial (i.e., TOPAZ or SAPPHIRE)
  • Nutritional status that was not stable over the past 6 months and is not anticipated to be stable throughout the trial or medical necessity for a gastric/nasogastric feeding tube, where the majority of feeds are given by this route, as assessed by the Investigator
  • Patient is currently enrolled in any investigational drug trial other than TOPAZ or SAPPHIRE
  • Prior history of severe hypersensitivity reaction or intolerance to SMN-targeted therapies
  • Prior history of severe hypersensitivity reaction or intolerance to apitegromab
  • Use of chronic daytime noninvasive ventilatory support for >16 hours daily in the 2 weeks before dosing, or anticipated to regularly receive such daytime ventilator support chronically throughout the trial
  • Any acute or comorbid condition interfering with the well-being of the patient at the patient's last visit in TOPAZ or SAPPHIRE, (including active systemic infection, the need for acute treatment, or inpatient observation due to any reason). After resolution of the condition, the patient can be enrolled in the trial if they meet all the other eligibility criteria.
  • Pregnant or breastfeeding
  • Any other condition or clinically significant laboratory result or ECG value that, in the opinion of the Investigator, may compromise safety or compliance, would preclude the patient from successful completion of the trial, or interfere with the interpretation of the results

Treatment and study plan

Apitegromab

Drug

Apitegromab (SRK-015) is an investigational, fully human immunoglobulin G4 monoclonal antibody that specifically binds to human proforms (i.e., inactive precursor forms) of myostatin, pro- and latent- myostatin, with high affinity, inhibiting activation of myostatin, a negative regulator of muscle growth and strength.

Primary outcomes

  1. Evaluate the long-term safety and tolerability of apitegromab in patients with Type 2 and Type 3 SMA

    Time frame: Up to 6 years

    Incidence of TEAEs and SAEs by severity

Secondary outcomes

  1. Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points

    Time frame: Up to 6 years

    Hammersmith Functional Motor Scale Expanded (HFMSE) total score at prespecified time points (excludes ambulatory patients)

  2. Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points

    Time frame: Up to 6 years

    Revised Upper Limb Module (RULM) total score at prespecified time points (excludes ambulatory patients)

  3. Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points

    Time frame: Up to 6 years

    Number of World Health Organization (WHO) motor development milestones attained at prespecified time points (excludes ambulatory patients)

  4. Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points

    Time frame: Up to 6 years

    Revised Hammersmith Scale (RHS) total score

  5. Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points

    Time frame: Up to 6 years

    Results for 6-Minute Walk Test

  6. Evaluate the long-term efficacy of apitegromab by assessing changes in motor function outcome measures at prespecified time points

    Time frame: Up to 6 years

    30-Second Sit-to-Stand

  7. Further evaluate the immunogenicity of apitegromab

    Time frame: Up to 6 years

    Presence or absence of antidrug antibody (ADA) against apitegromab in serum from blood samples

Other outcomes

  1. Further characterize the PK of apitegromab

    Time frame: Up to 6 years

    Apitegromab concentrations in serum from blood samples at prespecified time points

  2. Further evaluate the pharmacodynamic (PD) effects of apitegromab

    Time frame: Up to 6 years

    Total latent myostatin concentrations in blood samples at prespecified time points

  3. To further evaluate the effect of apitegromab on patient/caregiver-reported disability, and fatigability.

    Time frame: Up to 6 years

    Pediatric Evaluation of Disability Inventory Computer Adaptive Test (PEDI-CAT) at prespecified time points

  4. To further evaluate the effect of apitegromab on patient/caregiver-reported disability, and fatigability.

    Time frame: Up to 6 years

    Patient-reported Outcomes Measurement Information System (PROMIS) Fatigue Questionnaire at prespecified time points

  5. To further evaluate the effect of apitegromab on patient/caregiver-reported disability, and fatigability.

    Time frame: Up to 6 years

    Assessment of Caregiver Experience with Neuromuscular Disease (ACEND) at prespecified time points

Sponsors and collaborators

Lead sponsor

Scholar Rock, Inc.

Industry

Registry information

Official study title

An Open-Label, Multicenter, Extension Trial to Evaluate the Long-Term Safety and Efficacy of Apitegromab in Patients With Type 2 and Type 3 Spinal Muscular Atrophy Who Completed Previous Investigational Trials of Apitegromab

Acronym: ONYX

Important dates

Study start
2023
Primary completion
2026
Study completion
2029
First posted
Nov 25, 2022
Registry last updated
May 25, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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