Deflazacort Superior to Prednisone for Treatment of Duchenne Muscular Dystrophy

Stuart Peltz, PhD

Real-world data from a study show greater improvements in scoliosis, lean body mass, and mobility among patients with Duchenne muscular dystrophy (DMD) treated with deflazacort (Emflaza; PTC Therapeutics) compared with prednisone. Results of the analysis, conducted at Cincinnati Children’s Hospital Medical Center (CCHMC) in Ohio, were presented at the 2019 Child Neurology Society Annual Meeting, October 23-26, 2019 in Charlotte, North Carolina.

The analysis included more than 200 boys with DMD, of whom 75% (95% daily) received deflazacort and 13% (75% daily) received prednisone. The remaining 12% switched from prednisone to deflazacort, with an average duration of 3.1 years on prednisone and 2.5 years on deflazacort.

In a regression model that accounted for age and steroid duration, patients who received treatment with deflazacort versus prednisone on average had a 0.59 stairs/second greater 4-stair climb velocity, a 4.6 point higher North Star Ambulatory Assessment total score, and a 9.9% higher forced vital capacity %-predicted (P <.05 for all). Notably, patients treated with deflazacort had a lower total body mass of 6.9kg, 6.2 cm lower height, and an increase in lean body mass by 4.4%.

Results of a Kaplan-Meier analyses showed that 56.4% of prednisone-initiated patients used a wheelchair as their primary means of mobility by age 15. That number increased to 85.1% by the time they turned 20. In comparison, 43.7% of deflazacort-initiated patients relied on a wheelchair as a primary means of mobility by age 15. That number increased to 78.7% by the time those same patients turned 20 (P <.01).

In addition, by age 15 13.7% (64.8%) of prednisone-initiated patients had scoliosis compared with 8.9% (33.7%) of deflazacort-initiated patients (P =.05). By age 20, this increased to 64.8% and 33.7%, respectively. These differences persisted after adjusting for age at steroid initiation. Results of sensitivity analyses showed that risk of scoliosis and wheelchair use among patients who switched from prednisone to deflazacort was numerically lower versuss patients who received consistent prednisone but higher versus those who received consistent deflazacort.

Deflazacort was initially approved in 2017 for treatment of DMD in patients age 5 and older; in June, the FDA expanded the indication to children with DMD age 2 to 5.

“We believe that treating patients as young as possible, when they still have a substantial amount of muscle, will have the greatest benefit for patients that are 2 years and older,” Stuart Peltz, PhD, chief executive officer of PTC Therapeutics, said in a statement in June.

Overall, the study demonstrates that deflazacort is associated with greater preservation of function in children with DMD compared with prednisone, as shown by lower scoliosis rates and lower rates of wheelchair necessity.

REFERENCE:

Marden J, Santos C, Schilling T. Deflazacort or Prednisone Treatment for Duchenne Muscular Dystrophy (DMD): Real-world Outcomes at Cincinnati Children’s Hospital Medical Center (CCHMC). Presented at: Child Neurology Society 2019 Annual Meeting. October 23-26, 2019; Charlotte, NC. Abstract #218.