Reldesemtiv (CK-2127107) is an activator of skeletal muscle troponin, a calcium-sensitive sarcomere protein. By slowing the rate of calcium release in skeletal muscles, it improves their contractility.
Several trials realized in healthy volunteers against placebo have showed its good tolerance and its effectiveness on muscle strength; it is being studied as a potential treatment for diseases associated with fatigue or muscle weakness.
Developed by Cytokinetics, reldesemtiv was evaluated between December 2015 and May 2018 in 18 centers in North America in 70 patients with type II, III and IV SMA, over 12 years-old. For two months, participants in this phase II, randomized, double-blind trial received orally either reldesemtiv twice daily at a dose of 150 mg (24 participants) or 450 mg (20 participants), or placebo (26 participants).
The results, published in February 2021, show:
- good tolerance to the two doses tested,
- a significant improvement in respiratory function (maximum expiratory pressure or MEP) in patients on reldesemtiv at both doses, compared to the placebo group,
- a significant increase in the walking distance covered in six minutes by the patients who received reldesemtiv 450 mg compared to the placebo group.
The investigators of this trial suggest to evaluate this treatment, which does not affect the production of SNM like the drugs recently authorized in SMA, in a larger number of patients.
