medwireNews: UK study findings indicate that a slow-release formulation of the gonadotropin-releasing hormone analogue (GnRHa) triporelin given every 24 weeks is as effective as the standard 12-weekly treatment for central precocious puberty (CPP).
Sasha Howard (Queen Mary University of London, UK) and colleagues explain that the 22.5 mg depot injection of triptorelin given every 24 weeks has been “used increasingly in the UK” following a trial demonstrating its efficacy and safety in 44 children with CPP but that research has yet to directly compare efficacy or tolerability versus the 12-weekly 11.25 mg preparation.
To investigate, the team collated medical records for patients attending one of the three UK paediatric endocrinology centres between September 2008 and December 2024, identifying 62 girls and seven boys given the 12-weekly formulation, and 86 girls and nine boys given the 24-weekly formulation.
The children were aged an average of 7.5 years at baseline. Height standard deviation scores (SDS) at baseline were comparable between the 12-weekly and 24-weekly treatment groups for girls (median 1.45 vs 1.36) and boys (1.38 vs 1.38). This was also true for height, weight and BMI and, as expected for CPP, the children had advanced bone age relative to chronological age.
At baseline, 37% of girls were tanner breast (B) stage 2, 43% B3, 18% B4 and 2% B5, while 27% were pubic hair (P) stage 1, 34% P2, 23% P3, 13% P4 and 2% P5. The majority (60%) of girls were axillary hair (A) stage 1, 32% A2, and 9% A3.
Of the boys, none of them were Tanner genital (G) stage 1, 41% were G2, 30% G3, 19% G4 and 11% G5. P stage was P1 in 7%, P2 in 48%, P3 in 19%, P4 in 26% and P5 in 0%, and most (86%) were stage A1, while 14% were A2.
At the end of data collection, 162 patients had completed treatment, 77 were continuing on treatment, and eight were lost to follow-up. The median treatment duration for the 12-weekly and 24-weekly formulations were 37.5 and 27.2 months, respectively, for the girls, and 49.4 and 33.5 months for the boys.
Post-treatment outcomes were available for 69 patients given 12-weekly and 95 patients given 24-weekly formulations, but “[g]irls constituted the majority of patients in both treatment groups, reflecting the known epidemiology of CPP”, and formal comparisons were often not possible for the boys due to small numbers, the researchers say.
Howard et al report that height SDS was comparable between the 24- and 12-weekly treatment groups at 1 year (1.23 vs 1.40) and 2 years (1.28 vs 1.12) for combined groups of girls and boys, and height velocity was similar in girls in the two arms at 6 months, 1 year and 2 years. There were also no significant differences in median BMI SDS between the two treatment groups at 1 or 2 years, and this was true for both girls and boys.
The team assessed the impact of treatment on pubertal progression in girls and found no differences in Tanner stage progression between the groups for breast, pubic hair or axillary hair development.
Moreover, at 2 years there was no significant bone advancement in the girls of either treatment group, and bone age for chronological age remained comparable, the researchers say.
Analysis of biochemical markers of pubertal progression in 50 children attending one clinic revealed no significant differences between the girls in the 24- and 12-weekly treatment groups for lutenising hormone (LH), oestradiol or follicle-stimulating hormone. After 1 year, adequate suppression of LH (basal <1 IU/L before injection) was achieved by a comparable 75% of the seven girls given the 24-weekly treatment and 86% of seven girls given the 12-week treatment, and at 2 years all girls had achieved LH suppression.
“Both formulations were generally well tolerated, with most adverse events being mild and consistent with the known side-effect profile of GnRHa therapy”, the researchers summarise.
The 24- and 12-weekly treatments were associated with a similar frequency of injection site pain (8 vs 10%), mood swings (9 vs 7%), weight gain (2 vs 6%) and abdominal pain (3 vs 3%), with one participant in each group experiencing both mood swings and weight gain.
Thirteen children had experience of both treatments and all stated a preference for the 24-weekly formulation, “citing reduced appointment frequency, reduced disruption to schooling and reduced disruption to family life” as reasons, Howard and co-authors write in the Journal of Clinical Endocrinology & Metabolism.
The authors therefore conclude that, “[g]iven the comparable efficacy and tolerability of the two regimens demonstrated in this study”, use of the 24-weekly formulation “is a reasonable first-line approach for most children with CPP.”
However, they suggest: “In those requiring additional clinical caution, such as younger children or boys, scheduling an early clinical and biochemical review after treatment initiation may be appropriate to confirm adequate suppression and guide ongoing management.
“This strategy preserves the benefits of reduced injection frequency while allowing timely identification of suboptimal response in higher-risk groups.”
By Lynda Williams
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