Tadalafil does not help lessen ambulatory ability decline in boys with DMD
Tadalafil may not be effective for reducing the decline in ambulatory ability in boys with Duchenne muscular dystrophy (DMD), as shown in a recent study.
The study randomized 331 boys (mean age 9.6 years) with DMD to receive tadalafil 0.3 mg·kg−1·d−1, tadalafil 0.6 mg·kg−1·d−1 or placebo for 48 weeks. Efficacy was assessed using the 6-minute walk distance (6MWD). Secondary efficacy measures were North Star Ambulatory Assessment and timed function tests. Performance of Upper Limb (PUL) was examined as a prespecified exploratory outcome.
Tadalafil did not exert an effect on the primary outcome. The 6MWD after 48 weeks of treatment decreased by 51.0 m with placebo, 64.7 m with low-dose tadalafil (p=0.307 vs placebo) and 59.1 m with high-dose tadalafil (p=0.538 vs placebo). The drug had no effect on secondary outcomes.
In the group of patients aged >10 years, those treated with low-dose tadalafil showed smaller declines in total PUL score and shoulder subscore compared with those who received placebo.
Drug-related adverse events were reported in 41.4 percent of patients in the placebo group, 50.0 percent in the low-dose tadalafil group and 59.8 percent in the high-dose tadalafil group.
Adverse events were consistent with the known safety profile of tadalafil and the DMD disease state, researchers noted. “Safety monitoring revealed the expected increase in penile erections with tadalafil without priapism.”
Additional research is warranted to determine whether ambulatory decline in DMD can be lessened by initiation of PDE5 inhibition before 7 years of age, researchers said.