A phase 3 randomized placebo-controlled trial of tadalafil for Duchenne muscular dystrophy by Victor, RG, Sweeney, HL, Finkel, R, McDonald, CM, Byrne, B, Eagle, M, Goemans, N, Vandenborne, K, Dubrovsky, AL, Topaloglu, H, Miceli, MC, Furlong, P, Landry, J, Elashoff, R, Tadalafil DMD Study Group, Servais, L