CONTEXT
Therapeutic use of GHRH to enhance GH secretion is limited by its short duration of action.
Article breakdown
Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults.
The Journal of clinical endocrinology and metabolism • 2006 Mar • Vol 91, 799-805. PMID 16352683.
In healthy adults, injections of CJC-1295 raised growth hormone and IGF-I levels for days to weeks, much longer than standard GH-releasing hormone is described as lasting. The hormone response increased with higher doses, and repeated dosing appeared to build on prior doses. In these short trials, no serious adverse reactions were reported, but this study tested healthy volunteers rather than patients needing treatment.
In short
What this paper found
In healthy adults, injections of CJC-1295 raised growth hormone and IGF-I levels for days to weeks, much longer than standard GH-releasing hormone is described as lasting.
The hormone response increased with higher doses, and repeated dosing appeared to build on prior doses.
In these short trials, no serious adverse reactions were reported, but this study tested healthy volunteers rather than patients needing treatment.
Deep dive
What the paper is actually saying
Why This Paper Exists
Regular GH-releasing hormone has a short duration of action, which limits its therapeutic use. The authors studied whether a longer-acting version could keep growth hormone-related signals elevated for longer after injection.
What The Authors Wanted To Answer
The authors wanted to know how long CJC-1295 stays in the body, how strongly it increases GH and IGF-I, whether the effect depends on dose, and whether it appeared safe in healthy adults.
How The Study Was Done
This was a pair of randomized, placebo-controlled, double-blind, ascending-dose trials at two research sites. Healthy adults ages 21 to 61 received either subcutaneous CJC-1295 or placebo, first as single doses and then as weekly or every-2-week repeated doses, and the researchers measured blood levels of CJC-1295, GH, and IGF-I over time.
What The Study Found
A single CJC-1295 injection increased average GH levels about 2- to 10-fold for at least 6 days and increased average IGF-I levels about 1.5- to 3-fold for 9 to 11 days. The estimated half-life of CJC-1295 was 5.8 to 8.1 days. With multiple doses, average IGF-I levels stayed above baseline for as long as 28 days, suggesting a cumulative effect. No serious adverse reactions were reported.
Takeaway
In this early interventional study, CJC-1295 produced prolonged, dose-related increases in GH and IGF-I in healthy adults and appeared reasonably well tolerated over the study period. The abstract supports its potential as a therapy, but it does not show clinical benefits in patients.
Limits
What this abstract does not fully answer
The study was done in healthy adults, so the results do not show whether the drug improves symptoms or outcomes in patients with disease.
The trials were short-term, lasting 28 and 49 days, so long-term safety and durability are not addressed in the abstract.
The abstract does not report the number of participants, which makes it hard to judge the precision of the findings or how well uncommon side effects could be detected.
Key numbers
Numbers the abstract makes important
28 and 49 days
Length of the two trials, showing this was a short-term study.
Ages 21-61 years
Age range of the healthy participants studied.
2- to 10-fold increase in GH
After one injection, average plasma growth hormone rose several times above baseline, depending on dose.
6 days or more
How long the GH increase lasted after a single injection.
1.5- to 3-fold increase in IGF-I
After one injection, average IGF-I also rose above baseline in a dose-dependent way.
9-11 days
How long the IGF-I increase lasted after a single injection.
Source abstract
Original abstract sections
OBJECTIVE
The objective of this study was to examine the pharmacokinetic profile, pharmacodynamic effects, and safety of CJC-1295, a long-acting GHRH analog.
DESIGN
The study design was two randomized, placebo-controlled, double-blind, ascending dose trials with durations of 28 and 49 d.
SETTING
The study was performed at two investigational sites.
PARTICIPANTS
Healthy subjects, ages 21-61 yr, were studied.
INTERVENTIONS
CJC-1295 or placebo was administered sc in one of four ascending single doses in the first study and in two or three weekly or biweekly doses in the second study.
MAIN OUTCOME MEASURES
The main outcome measures were peak concentrations and area under the curve of GH and IGF-I; standard pharmacokinetic parameters were used for CJC-1295.
RESULTS
After a single injection of CJC-1295, there were dose-dependent increases in mean plasma GH concentrations by 2- to 10-fold for 6 d or more and in mean plasma IGF-I concentrations by 1.5- to 3-fold for 9-11 d. The estimated half-life of CJC-1295 was 5.8-8.1 d. After multiple CJC-1295 doses, mean IGF-I levels remained above baseline for up to 28 d. No serious adverse reactions were reported.
CONCLUSIONS
Subcutaneous administration of CJC-1295 resulted in sustained, dose-dependent increases in GH and IGF-I levels in healthy adults and was safe and relatively well tolerated, particularly at doses of 30 or 60 microg/kg. There was evidence of a cumulative effect after multiple doses. These data support the potential utility of CJC-1295 as a therapeutic agent.