The RESPONSE trial

The RESPONSE trial results: NT100 (a man-made form of a protein called G-CSF) did not improve outcomes in women with a history of unexplained recurrent miscarriages.

About the RESPONSE trial

RESPONSE was a randomised, double-blind, placebo controlled clinical trial (see box below) involving 150 women with a history of unexplained recurrent pregnancy loss.  It was conducted at 21 UK hospitals between 23 June 2014 and 05 June 2016 and coordinated by the University of Birmingham. The Miscarriage Association’s National Director was a lay member of the Trial Oversight Group.

Of the 150 women who took part in the trial, 76 were randomised to NT100 (recombinant human granulocyte – colony stimulating factor, or G-CSF) and 74 to placebo. Treatment began from as early as three to five weeks gestation for a maximum of 9 weeks.

The results* showed no significant increase in clinical pregnancy or live births with the use of NT100 in the first trimester of pregnancy.There were also no significant differences between the treatment and placebo groups in any of the additional areas studied, including miscarriages, livebirth, adverse events, stillbirth, neonatal birth weight, major congenital anomalies or preterm births.

Randomised: The women who took part were given either the treatment medicine (NT100) or a placebo – a dummy drug that has no active ingredients. A computer made the selection so it was completely random.
Double-blind The women in the trial weren’t told whether they were taking the active medicine (NT100) or the placebo – and neither were their doctors. So both were “blinded” to this information.  (This blinding was removed in  February 2018 for women in the trial who wished to find out which group they had been in.)
Placebo-controlled Half of the women in the study had the active medicine and half the placebo (they are called the control group). The medication that they received looked exactly the same to them and their doctors, but a completely separate study group kept a record of which women had NT100 and which had the placebo.

* Published in Human Reproduction on 18 Feb 2019.