Study wrapper · #250
Once-daily administration of CJC-1295, a long-acting growth hormone-releasing hormone (GHRH) analog, normalizes growth in the GHRH knockout mouse.
Editor's note
A rodent efficacy study — a real test of what CJC-1295 does, but in mice, not people. Using GHRH-knockout mice (which cannot make their own GHRH and grow poorly even with twice-daily short-acting analogue), researchers gave CJC-1295 every 24, 48, or 72 hours for five weeks. Once-daily dosing normalised body weight and length and kept lean and subcutaneous fat mass normal; 48- and 72-hour intervals improved growth but did not fully normalise it. Pituitary GH mRNA and somatotroph numbers rose, indicating the peptide drove cell proliferation, not just hormone release. This is a clean demonstration that CJC-1295's extended half-life translates into sustained biological effect and that dosing frequency matters. Caveats are the usual and important ones: it is a genetic-deficiency mouse model, not healthy or human physiology, and the endpoint is longitudinal growth in developing animals — not adult body composition, performance, or anti-ageing. These are preclinical findings; human data are needed before clinical conclusions can be drawn. It complements, but does not extend, the small Phase II human PK/PD evidence.
Plain-language abstract
This study tested CJC-1295 in mice bred to lack their own growth-hormone-releasing hormone (GHRH), which makes them grow poorly. Even giving these mice a short-acting GHRH drug twice a day fails to fix their growth. CJC-1295 is a synthetic GHRH that attaches permanently to a blood protein after injection, so it lasts much longer. The researchers treated one-week-old GHRH-deficient mice for five weeks with 2 micrograms of CJC-1295 given every 24, 48, or 72 hours, and compared them with untreated mice and with normal-growing relatives. Mice given a dose every 24 hours reached normal body weight and length, and their lean and under-the-skin fat mass were normal. Mice dosed every 48 or 72 hours grew better than untreated mice but did not fully catch up. Treatment increased the amount of growth-hormone genetic material in the pituitary and the number of hormone-producing cells, suggesting these cells had multiplied. The main lesson is that daily dosing worked best, and spacing doses further apart worked less well. These results are from a mouse model of a genetic hormone deficiency and concern childhood growth; they do not show what CJC-1295 does in healthy animals or humans, or in adults, and do not address its safety in people.