Scholar Rock have recently announced the latest data from the TOPAZ trial, which is a phase 2 study designed to assess the safety and efficacy of Apitegromab given in combination with Spinraza (nusinersen) or Evrysdi (risdiplam).
Apitegromab is a muscle-directed therapy that aims to reverse or restrict the muscle atrophy and weakness experienced by SMA patients. It works by very specifically targeting an important protein called myostatin to inhibit its function and release the breaks on muscle growth.
After 36 months of the TOPAZ trial, the combination therapy continues to have a favourable safety profile. In addition, the treatment was shown to provide sustained increases in motor function and lead to improvements in patient-reported outcomes, such as reduced fatigue and enhanced ability to perform daily activities. The trial is being conducted with non-ambulatory (unable to walk independently) individuals aged 2-21 years living with SMA Type 2 or Type 3.
Apitegromab was associated with an average 4.0 point improvement in the Hammersmith Functional Motor Scale – Expanded (HFMSE) and a 2.4 point gain in the Revised upper limb module (RULM). These improvements are relative to the baseline test scores achieved by participants at the start of the study, when they will have been receiving SMN-dependent therapies for at least 6 months.
To date, more than 90% of the patients remain enrolled in the study, which is due for completion in April 2024.