News Release 

Duchenne muscular dystrophy prevalence increases, while incidence remains steady

Uptick attributed to improved treatments and longevity

Deerfield Management (Deerfield Institute Division)

New York, NY, May 20, 2019--In the first study of its kind involving Duchenne Muscular Dystrophy (DMD) in the U.S., researchers from the Deerfield Institute found that while the number of new cases has remained stable, there has been an uptick in prevalence--largely attributed to enhanced treatments and longevity. The study, which is titled "Duchenne Muscular Dystrophy Prevalence in the U.S.: A Novel Incidence-Based Modeling Approach Using System Dynamics", is scheduled for Poster Session ll on Monday, May 20 at the ISPOR 2019 annual meeting in New Orleans.

DMD, a genetic disorder characterized by progressive muscle degeneration and weakness, is caused by an absence of Dystrophin, a protein that helps keep muscle cells intact. Symptom onset is in early childhood, typically between ages 3 and 5. The disease primarily affects boys, but in rare cases it can affect girls.

Using a triangular distribution of incidence rates identified in the literature2,3, a sensitivity analysis was run to estimate the diagnosed incidence of DMD in the U.S. at 17.24 per 100,000 live male births, corresponding to approximately 362 incident cases in 2019; diagnosed prevalence was found to be 6.09 per 100,000 male population across all age groups, corresponding to about 10,015 prevalent cases in 2019.

The Deerfield Institute researchers found that while the majority (64.5%) of DMD patients are under the age of 20, there is a significant number of older DMD patients up to 45 years of age that were excluded from previous prevalence estimates. 4 The prevalence of DMD among males, aged 45 or younger, was found to be 10.0 per 100,000 vs previously estimated prevalence estimates of 1.38 per 10,000 among males 5 to 24 years of age.

"We hypothesized that the prevalence of DMD has increased over the past few decades, due predominantly to improvements in treatment and care" said Emma Giegerich, MPH, an epidemiologist with the Deerfield Institute and co-author of the study. "Our incidence-to-prevalence model was built using system dynamics principles and birth-cohort-specific survival curves to get the most accurate picture of the disease landscape and its current burden. The results indicate that there is a larger than expected patient population that may benefit from novel treatment interventions, such as targeted gene therapies, potentially improving the viability of current or future drug development programs."

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The study was co-authored by Mark Stuntz, MPH, a former Deerfield Institute investigator.

1 Retrieved from https://www.mda.org/disease/duchenne-muscular-dystrophy.

2 Dooley J, Gordon EK, Dodds L, MacSween J. Duchenne muscular dystrophy: a 30-year population-based incidence study. Clinical Pediatrics 2010;49(2):177-179.

3 Mendell JR, Shilling C, Leslie ND, Flanigan KM, al-Dahhak R, Gastier-Foster J, Kneile K, Dunn DM, Duval B, Aoyagi A, Hamil C, Mahmoud M, Roush K, Bird L, Rankin C, Lilly H, Street N, Chandrasekar R, Weiss RB. Evidence-based path to newborn screening for Duchenne muscular dystrophy. Ann Neurol 2012;71:304-313.

4 Romitti PA, Zhu Y, Puzhankara S, James KA, Nabukera SK, Zamba GK, Ciafaloni E, Cunniff C, Druschel CM, Mathews KD, Matthews DJ, Meaney FJ, Andrews JG, Conway KM, Fox DJ, Street N, Adams MM, Bolen J, STARnet MD. Prevalence of Duchenne and Becker muscular dystrophies in the United States. Pediatrics. 2015;135(3):513-21.

About the Deerfield Institute

The Deerfield Institute is the research division of Deerfield Management, a health care investment management firm committed to advancing health care through investment, information and philanthropy.

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