Association between Alanine Aminotransferase and Growth Hormone: A Retrospective Cohort Study of Short Children and Adolescents

Letrozole combined with rhGH treatment increases the adult height of short pubertal boys

OBJECTIVES

This study was performed to investigate the effectiveness of the combination of letrozole and recombinant human growth hormone (rhGH) to improve the predicted adult height (PAH) and final adult height (FAH) of Chinese short pubertal boys.

METHODS

In total, 171 Chinese short pubertal boys were recruited for this study. 96 of them received letrozole (2.5 mg/d) combined with rhGH (33.3-66.6 μg/kg.d), and the others received rhGH alone. Follow-up visits were conducted at 1, 3, 6, 9, and 12 months or regularly after the first treatment. During each visit, plasma samples were collected for clinical tests and biomedical analyses, all of which were performed according to standard protocols. This study was registered at www.chictr.org.cn under ID number ChiCTR1900026142.

RESULTS

After receiving treatment for at least 3 months, 68 boys (91 %) in the rhGH therapy group and 90 (94 %) in the letrozole combined with rhGH (letrozole+rhGH) therapy group achieved an increase in PAH, with the latter treatment leading to a more effective slowing of bone age (BA) advancement. Moreover, the increased PAH showed a significant positive correlation with treatment time in both groups, and letrozole+rhGH increased the PAH to a greater degree than rhGH alone (p=0.0023). And letrozole+rhGH not only slowed the increase in BA more efficiently than rhGH therapy alone (p=0.0025), but also achieved a higher FAH (p=0.0078).

CONCLUSIONS

Letrozole combined with rhGH treatment is a promising therapy to increase the PAH and FAH of Chinese short pubertal boys.

Off-label use of letrozole in Chinese short pubertal boys: Effectiveness, safety, and exposure-response analysis

AIMS

Recently, letrozole has been used off-label to treat short pubertal boys. The experience on letrozole effectiveness and safety has been obtained primarily from Caucasian children. A simple extrapolation of the data to Chinese paediatric populations is questionable because of the substantial ethnic differences between the two populations. Therefore, the present study aimed to determine the effectiveness and safety of letrozole use in Chinese short pubertal boys as well as to establish an exposure-response relationship.

METHODS

Forty-one Chinese boys were included in the study. Patients were given letrozole tablets (2.5 mg) once daily in combination with growth hormone, and follow-up visits were made after 1, 3, 6 and 12 months of treatment. Plasma samples were taken from clinical examinations and analysed using high performance liquid chromatography with fluorescence detection.

RESULTS

After 1 year of treatment, 35 (88%) boys showed increased predicted adult heights. However, possible adverse drug reactions were seen in nine boys (22%). Predicted adult heights increased significantly from 168.4 ± 3.7 to 173.0 ± 4.2 cm, while oestrogen levels dropped from 33.2 ± 7.4 to 21.6 ± 7.3 pg/mL. Increments in predicted adult height were significantly correlated with trough letrozole concentrations (r = 0.39, P = .01).

CONCLUSION

Letrozole treatment in Chinese pubertal populations should be further optimized, and more personalized therapies should be developed.