The unexpected1) Excellent safety was confirmed: "The top-line results confirm the excellent safety of macimorelin, similar to what was demonstrated in our clinical and commercial experience with the use of macimorelin to diagnose adult growth hormone deficiency (AGHD)."
2) Macimorelin is suppose to stimulate growth hormone in the subjects. The test is already approved in Europe and the US for adults and a previous dose-finding trial in children appeared successful. In this pediatric trial, however, some subjects produced far more growth hormone than expected based on the results of the other tests. An optimal growth hormone cut-off 156%-266% higher than standard cut-off rates would be required given how much growth hormone macimorelin stimulated.
"Based on this, top-line data present an ‘optimal’ growth hormone (GH) cut-off point of 25.59 ng/mL, which is substantially higher than the standard cut-off points of 7-10 ng/mL as defined in current guidelines with existing tests."
Compared to the two other growth hormone deficiency tests used in the trial why is so much growth hormone being produced in certain of the subjects when macimorelin is used? More analysis is needed; but the other tests may be falesly identifying some subjects as growth hormone deficient and when macimorelin is given and this is leading to the higher than expected growth hormone in the macimorelin subjects. The other tests may be worse than the industry expects and falsely classifying some subjects as growth hormone deficient?
"Although further analysis of the study results is required, initial review of the results indicates that the comparator tests may have led to a high false positive rate which impacted macimorelin’s ability to reach the primary efficacy endpoint. These unexpected results require further clarification and some re-analyses with the aim to consider the trial outcome and the strategy moving forward."