Use of vosoritide in children with achondroplasia - clinical experience

Ahmet Kahveci; Didem Helvacıoglu; Canbaz Aylin Tugba; Aylin Gunay; Abalı Zehra Yavas; Abdullah Bereket; Turan Serap Demircioglu

doi:10.1530/endoabs.110.P615

JOINT2713

Introduction and Aim: Achondroplasia is the most common form of rhizomelic short stature characterized by mutations in the FGFR3 gene. Vosoritide, a C-type natriuretic peptide analog, has shown promise in stimulating linear growth in children with achondroplasia. This study aims to present real-life experiences with the use of vosoritide in children diagnosed with achondroplasia.

Results: Our study was designed prospectively in children with achondroplasia receiving vosoritide treatment and aimed to find changes in annual growth rate and anthropometric parameters with treatment. The clinical features of 16 children (8 males) with a current mean age of 7. 85±4. 38 years who were diagnosed with achondroplasia were analyzed. Two of the cases were in the pubertal period. In antenatal follow-up, skeletal dysplasia was suspected in 81% of the cases and complications such as basilar invagination, foramen magnum stenosis and hydrocephalus were present in 13/16 of the cases. In polysomnographic evaluation, 31% had various degrees of sleep apnea and 19% (3/16) were receiving non-invasive mechanical ventilator support. All patients had a mean follow-up of 2. 94±2. 66 years without treatment. Vosoritide treatment was given 15 mg/kg/day for a mean duration of 0. 98±0. 57 years. There was a significant increase in the growth rate of the patients after vosoritide treatment compared to the pretreatment period (mean 5. 15±4. 89 cm/year, -2. 08±0. 91 SDS to 5. 99±1. 46 cm/year, -0. 19±1. 31 SDS; p:0. 03, <0. 001). Growth hormone stimulation test was performed in 5 patients with inadequate growth rates and low IGF-1 values under Vosoritide treatment and deficiency was detected in 2 patients. There was no significant difference in body segment measurements under treatment compared to before vosoritide treatment. This suggests that growth is proportional with vosoritide and that it maintains the typical body proportions for children with achondroplasia, but it remains to be seen in follow-up whether there will be a difference in longer treatment periods. Other anthropometric parameter evaluations are presented in Table 1.

Comparison of LS-BMD and TBLH-BMD Z-scores (Mann-Whitney test).
	Pre-Treatment n: 16	> 6 month treatment n:13	>12 month treatment n: 9	p value
Height SDS(Hoover)	0. 40±1. 18	0. 42±1. 22	0. 39±1. 13	0. 94
Leg Lenght SDS	0. 82±1. 70	0. 63±1. 41	0. 79±1. 59	0. 94
Sitting Height SDS	-0. 36±1. 40	0. 23±1. 83	-0. 06±1. 18	0. 58
Sitting Height/leg Lenght SDS	-1. 18±1. 42	-0. 69±1. 19	-0. 43±1. 46	0. 38
Sitting Height/Height SDS	-1. 32±1. 68	-0. 78±1. 41	-0. 82±1. 49	0. 59

Conclusions: Although vosoritide increases the growth rate in children with achondroplasia, its effect on height SDS and body proportions is thought to be significant in longer follow-up.

Endocrine Abstracts

P615