US-based biopharmaceutical firm Versartis has reported results from a Phase III clinical trial (VELOCITY) of somavaratan (VRS-317) to treat paediatric patients with growth hormone deficiency (GHD).

Somavaratan is an investigational long-acting form of recombinant human growth hormone (rhGH).

The results showed that the trial did not meet the primary endpoint of non-inferiority for primary efficacy variable, height velocity (HV) at 12 months, compared to daily growth hormone Genotropin.

Intent to treat (ITT) patients administered with somavaratan twice a month were found to have a 12-month HV of 9.44cm, while it was 10.7cm in the case of patients treated with Genotropin daily.

Performed in the US, Canada and Europe, the randomised, open-label, multi-centre Phase III registration trial evaluated somavaratan in pre-pubertal children with GHD.

“Somavaratan showed height velocity in the range we had hoped, but it was not sufficient to demonstrate non-inferiority in this trial.”

Versartis president and CEO Jay Shepard said: “Somavaratan showed height velocity in the range we had hoped, but it was not sufficient to demonstrate non-inferiority in this trial.

“We have done an initial analysis of the top-line data and are continuing to thoroughly review the results to gain greater insight into the trial outcome. We plan to provide a corporate update later this year.”

The non-inferiority was demonstrated in the per protocol population (PP), with the 12-month HV being 9.71cm for PP patients given somavaratan twice a month compared to 10.63cm a day of Genotropin.

During the trial, somavaratan was found to be well-tolerated, where treatment discontinuation rate was lower than that of the Genotropin group.

In addition to Phase III trials for paediatric GHD, somavaratan is being studied in a Phase II trial for adult GHD.