ORLANDO – About 80% of children with growth disorders will attain their expected normal adult height if adequately treated with growth hormone, a large observational study has determined.
Somatropin recombinant human growth hormone seemed most effective for patients with growth hormone deficiency, idiopathic short stature, and for those who were born small for gestational age. Patients who had Turner syndrome or a homeobox-deficiency gene didn’t do quite as well, although most did still improve their final height.
The Genetics and Neuroendocrinology of Short Stature International Study (GENESIS) followed more than 22,000 children who were treated in 30 countries from 1999 to 2015.
All of the patients were treated with somatropin recombinant human growth hormone (Humatrope). Eli Lilly, which makes the medication, sponsored the study and presented the results during a poster session at the annual meeting of the Endocrine Society. Representatives at the poster declined to discuss results with the media during the open session.
“The results speak for themselves,” said Cheri Deal, MD, PhD, of the University of Montreal, Quebec, one of the presenting authors. “It’s an incredible story.”
The GENESIS cohort comprised more than 22,000 children who were treated for a variety of growth disorders at 827 international sites.
Subanalyses have been published, but this is the first release of the data on 5,076 patients with full follow-up. Most of the patients (61%) received the medication for growth hormone deficiency. Other indications were Turner syndrome (14%), idiopathic short stature (11%), short-stature homeobox-containing gene deficiency (3%), small for gestational age (5%), and chronic renal insufficiency (0.3%). Other diagnoses, plus unknown causes, made up the remainder of the diagnoses.
The investigators, led by Christopher J. Child, PhD, an Eli Lilly scientist, split the cohort into diagnostic groups and treatment subgroups: those who attained normal adult height, those who attained normal adult height with at least 4 years of treatment, and those who gained normal adult height who started treatment at younger than 10 years of age.
At baseline, those with growth hormone deficiency were a mean of 11 years old; their height was a mean of 2.4 standard deviations (SDS) below normal. They received a mean of 6 years of treatment; 86% achieved a normal adult height, with an overall gain of 1.39 SDS. Those who started somatropin before age 10 years made bigger gains. The final height gain was 1.78 SDS after a mean of 9.5 years of treatment.
At baseline, those with idiopathic short stature were a mean of 12 years old; their mean height was 2.3 SDS below normal. They received a mean of 4.7 years of treatment; 82% achieved normal height, with a gain of 1.1 SDS. Starting somatropin at a younger age (mean 8 years) improved outcomes slightly, with a final height gain of 1.6 SDS after 8 years of treatment.
Patients with Turner syndrome were a mean of 10 years when they started treatment; their mean height was 2.65 SDS below normal. They received a mean of 6.4 years of treatment; 66% achieved normal adult height, with a mean height gain of 0.95 SDS. Early treatment didn’t alter outcomes much in this group. After a mean of 8.5 years of treatment, 65% achieved normal height, with a height gain of 0.84 SDS.
Patients with a short-stature homeobox-containing gene deficiency were a mean of 11 years when they started treatment. At that time, their height was a mean of 2.36 SDS below normal. They were treated for a mean of 4.7 years; 76% achieved a normal adult height, with a mean gain of 0.86 SDS. Early treatment did improve outcomes a bit. After a mean treatment time of 7 years, 78% gained normal adult height, with a height gain of 0.84 SDS.
Children who were small for gestational age started treatment when they were a mean of 10.5 years. At that time, their mean height was 2.57 SDS below normal. They were treated for a mean of 5.4 years; 78% attained a normal adult height, with a mean gain of 1.1 SDS. Early treatment improved outcomes. After a mean treatment time of 7.8 years, 81% achieved normal adult height, with a mean gain of 1.41 SDS.
The less-robust gains seen in the children with genetically influenced growth disorders “wasn’t unexpected” and is in line with what has been observed in a number of clinical trials, the investigators said.
Eli Lilly manufactures the somatropin product used in the study, and it sponsored the study. Dr. Child is an employee of the company. Dr. Deal did not have any financial disclosures.
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