Ondansetron and metoclopramide as second-line antiemetics in women with nausea and vomiting in pregnancy: the EMPOWER pilot factorial RCT.

BACKGROUND

Around one-third of pregnant women suffer from moderate to severe nausea and vomiting, causing physical and emotional distress and reducing their quality of life. There is no cure for nausea and vomiting in pregnancy. Management focuses on relieving symptoms and preventing morbidity, and often requires antiemetic therapy. National guidelines make recommendations about first-, second- and third-line antiemetic therapies, although care varies in different hospitals and women report feeling unsupported, dissatisfied and depressed.

OBJECTIVES

To determine whether or not, in addition to intravenous rehydration, ondansetron compared with no ondansetron and metoclopramide compared with no metoclopramide reduced the rate of treatment failure up to 10 days after drug initiation; improved symptom severity at 2, 5 and 10 days after drug initiation; improved quality of life at 10 days after drug initiation; and had an acceptable side effect and safety profile. To estimate the incremental cost per treatment failure avoided and the net monetary benefits from the perspectives of the NHS and women.

DESIGN

This was a multicentre, double-dummy, randomised, double-blinded, dummy-controlled 2 × 2 factorial trial (with an internal pilot phase), with qualitative and health economic evaluations.

PARTICIPANTS

Thirty-three patients (who were < 17 weeks pregnant and who attended hospital with nausea and vomiting after little or no improvement with first-line antiemetic medication) who attended 12 secondary care NHS trusts in England, 22 health-care professionals and 21 women participated in the qualitative evaluation.

INTERVENTIONS

Participants were randomly allocated to one of four treatment groups (1 : 1 : 1: 1 ratio): (1) metoclopramide and dummy ondansetron; (2) ondansetron and dummy metoclopramide; (3) metoclopramide and ondansetron; or (4) double dummy. Trial medication was initially given intravenously and then continued orally once women were able to tolerate oral fluids for a maximum of 10 days of treatment.

MAIN OUTCOME MEASURES

The primary end point was the number of participants who experienced treatment failure, which was defined as the need for further treatment because symptoms had worsened between 12 hours and 10 days post treatment. The main economic outcomes were incremental cost per additional successful treatment and incremental net benefit.

RESULTS

Of the 592 patients screened, 122 were considered eligible and 33 were recruited into the internal pilot (metoclopramide and dummy ondansetron,

LIMITATIONS

The pilot trial failed to achieve the recruitment target owing to unforeseen changes in the provision of care.

CONCLUSIONS

The trial was unable to provide evidence to support clinician decisions about the best choice of second-line antiemetic for nausea and vomiting in pregnancy.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN16924692 and EudraCT 2017-001651-31.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in

Nausea and vomiting in pregnancy cause physical and emotional distress, and up to 30% of affected women require medical treatment. Guidelines on the use of anti-sickness drugs exist, but evidence is limited about which drugs work the best. The EMPOWER (EMesis in Pregnancy – Ondansetron With mEtoClopRamide) trial aimed to compare the clinical effectiveness and cost-effectiveness of two anti-sickness drugs [metoclopramide (metoclopramide hydrochloride, Actavis UK Ltd, Barnstable, UK; IV Ratiopharm GmbH, Ulm, Germany) and ondansetron (ondansetron hydrochloride dehydrate, Wockhardt UK Ltd, Wrexham, UK; IV Hameln Pharma plus GmbH, Hameln)] for the treatment of nausea and vomiting in pregnancy. Women who were < 17 weeks pregnant with severe nausea and vomiting who attended hospital because their first anti-sickness drug had failed to improve their symptoms were asked to take part in the trial. Participants received fluids and, with consent, were randomly allocated to one of four groups: (1) metoclopramide and dummy ondansetron, (2) ondansetron and dummy metoclopramide, (3) metoclopramide and ondansetron or (4) double dummy. Trial drugs were administered into a vein and then by tablet for 10 days. On advice from sufferers, the trial focused on treatment failure, but other outcomes, including drug side effects, costs and pregnancy outcome, were collected. The trial was unable to recruit enough women and, therefore, did not progress. Nearly 600 women at 11 hospitals were screened, of whom 122 (21%) were eligible and 33 were recruited. The main reason for ineligibility (68%) was prior use of trial drug (mostly ondansetron). Overall, 15 out of 30 evaluable women experienced treatment failure. Interviews with 21 women who were approached about the trial and 22 research staff identified complex hurdles to and enablers of recruitment. The main hurdles were the requirements of the study protocol in relation to guidelines on anti-sickness drugs and the diversity of pathways to care. The role of research staff was a key enabler. The trial was too small to draw useful conclusions and it highlights the challenges of conducting complex studies on sick pregnant women. Subsequent concerns about the safety of ondansetron highlight the need for further studies to help inform women and the NHS about the best care for nausea and vomiting in pregnancy.