Reldesemtiv in Patients with Spinal Muscular Atrophy: a Phase 2 Hypothesis-Generating Study

Stacy A. Rudnicki, Jinsy A. Andrews, Tina Duong, Bettina M. Cockroft, Fady I. Malik, Lisa Meng, Jenny Wei, Andrew A. Wolff, Angela Genge, Nicholas E. Johnson, Carolina Tesi-Rocha, Anne M. Connolly, Basil T. Darras, Kevin Felice, Perry B. Shieh, Jean K. Mah, Jeffrey Statland, Craig Campbell, Ali A. Habib, Nancy L. KuntzMaryam Oskoui, John W. Day*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


This phase 2, double-blind, placebo-controlled, hypothesis-generating study evaluated the effects of oral reldesemtiv, a fast skeletal muscle troponin activator, in patients with spinal muscular atrophy (SMA). Patients ≥ 12 years of age with type II, III, or IV SMA were randomized into 2 sequential, ascending reldesemtiv dosing cohorts (cohort 1: 150 mg bid or placebo [2:1]; cohort 2: 450 mg bid or placebo [2:1]). The primary objective was to determine potential pharmacodynamic effects of reldesemtiv on 8 outcome measures in SMA, including 6-minute walk distance (6MWD) and maximum expiratory pressure (MEP). Changes from baseline to weeks 4 and 8 were determined. Pharmacokinetics and safety were also evaluated. Patients were randomized to reldesemtiv 150 mg, 450 mg, or placebo (24, 20, and 26, respectively). The change from baseline in 6MWD was greater for reldesemtiv 450 mg than for placebo at weeks 4 and 8 (least squares [LS] mean difference, 35.6 m [p = 0.0037] and 24.9 m [p = 0.058], respectively). Changes from baseline in MEP at week 8 on reldesemtiv 150 and 450 mg were significantly greater than those on placebo (LS mean differences, 11.7 [p = 0.038] and 13.2 cm H2O [p = 0.03], respectively). For 6MWD and MEP, significant changes from placebo were seen in the highest reldesemtiv peak plasma concentration quartile (Cmax > 3.29 μg/mL; LS mean differences, 43.3 m [p = 0.010] and 28.8 cm H2O [p = 0.0002], respectively). Both dose levels of reldesemtiv were well tolerated. Results suggest reldesemtiv may offer clinical benefit and support evaluation in larger SMA patient populations.

Original languageEnglish (US)
Pages (from-to)1127-1136
Number of pages10
Issue number2
StatePublished - Apr 2021


  • Reldesemtiv
  • pharmacodynamics
  • pharmacokinetics
  • six-minute walk test
  • spinal muscular atrophy clinical trial

ASJC Scopus subject areas

  • Clinical Neurology
  • Pharmacology (medical)
  • Pharmacology


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