ESPE Abstracts

Background: The 2018 international standards of care for DMD recommend initiating testosterone for management of delayed puberty commencing at a low dose, gradually increasing to adult replacement. No recommendations exist regarding longer term use of testosterone during transition and adulthood.

Aim(s): To report long-term use of testosterone in DMD with outcomes of gonadal function and pubertal development in those who discontinued testosterone therapy.

Methods: 35 boys with DMD were treated with testosterone between two centres. 24 boys included in this report were treated with testosterone for >1 year, with information following discontinuation of testosterone. Results are reported as median(range).

Results: Centre A initiated testosterone with oral testosterone undecanoate or transdermal testosterone gel and transitioned to long-acting injectable testosterone undecanoate at Tanner stage IV virilization, regardless of testis volume. Testosterone was discontinued after at least 16 years of age. Median age at discontinuation of 18.0 years(16.1, 21.8). Centre B initiated testosterone with short-acting injectable testosterone proprionate or transdermal testosterone. Testosterone was ceased with increasing testicular size(at least 6 ml) or if LH levels were detectable and rising even with testes <6 ml. Median age at discontinuation of 17.2 years(14.3, 18.0) Combining both centres data, median age of initiating testosterone was 14.3 years(12.8, 17.8). Median age at discontinuation was 17.6 years(14.3, 21.8). Median age of first assessment following discontinuation of testosterone was 18.3(15,22.4). Median testosterone(samples before 11 am) was 9.9 nmol/L(<0.5, 25.7). 7/24(29%) had testosterone levels <6.9 nmol/L, with median testosterone of 3.3 nmol/L(<0.5, 6.5). In a sub-set of 11 boys, testicular volume was assessed at discontinuation of testosterone and following discontinuation of testosterone. 8/11 had increase in testicular volume with median testicular volume of 10 ml(6,20). Two boys(18%) had no testicular growth: A 17.9 year old with testicular volume 1 ml, adult virilization(G5P5) and early morning testosterone of 4.5 nmol/L; and a 17.1 year old with bilateral inguinal testes, adult viriization(G5P5), no growth on testicular ultrasound and early morning testosterone of 1.4 nmol/L.

Conclusion: We provide early data regarding withdrawal of testosterone treatment for pubertal delay in boys with DMD. Almost 30% of adolescents and men with DMD had testosterone levels <6.9 nmol/L, indicating a need for long term hormone replacement therapy. Clinical pathways in this area are needed and requires attention during the transition period.