Page last updated: 11th August 2025

SAPPHIRE Trial

Informed by the results of the TOPAZ trial (see below), SAPPHIRE was a randomised, double-blind, placebo-controlled Phase 3 study that aimed to assess the safety and efficacy of apitegromab in conjunction with SPINRAZA® (nusinersen) or EVRYSDI® (risdiplam). Trial participants were non-ambulatory individuals aged 2-21 years living with Type 2 or Type 3 SMA. The SAPPHIRE trial was completed in December 2024 and showed that apitegromab treatment caused statistically significant and clinically-meaningful improvements in motor function.

Trial results and updates >

TOPAZ Trial

This Phase 2 study by Scholar Rock was a proof-of-concept trial designed to assess the safety and efficacy of apitegromab in conjunction with SPINRAZA® (nusinersen) or EVRYSDI® (risdiplam). Trial participants were non-ambulatory (unable to walk independently) individuals aged 2-21 years living with SMA Type 2 or Type 3. The extension phase of TOPAZ was completed in February 2024 and concluded that apitegromab led to improved motor function.

ClinicalTrials.Gov >

Trial results and updates >

ONYX Trial

This is an ongoing open-label Phase 3 study by Scholar Rock designed to assess the long-term safety and efficacy of apitegromab in people living with Type 2 and Type 3 SMA who completed the TOPAZ or SAPPHIRE trial (see above). ONYX is due to be completed in 2029.

ClinicalTrials.Gov >