Atosiban as a potential treatment for endometriosis

Endometriosis is a common chronic, incurable condition of unknown etiology in
which endometrium-like tissue implants outside the uterus. In the Netherlands
405,000 women are estimated to have endometriosis in some degree. Symptoms may
vary through the menstrual cycle and include but are not limited to:
dysmenorrhea, chronic pelvic pain, dyspareunia and dyschezia. Current treatment
consists of analgesics, hormonal treatment and more or less invasive surgery.
Following histological findings and in vitro and animal research oxytocin
receptor antagonist might be an alternative, non-hormonal, non-invasive
treatment option. Except for one study on advanced reproductive techniques, no
studies have reported the use of oxytocin receptor antagonists in human
patients. We hypothesize atosiban can significantly lower patient*s pain
scores. If this pilot study shows atosiban can be a treatment option for women
with endometriosis, we intend to develop a patient-friendly mode of
administration for atosiban.

To investigate the potential of atosiban as a treatment for pain caused by
endometriosis.

Phase II interventional pilot study

Atosiban 6,75 mg intravenously bolus, followed by 18 mg per hour continuous
infusion for 3 hours, followed by 6 mg per hour continuous infusion for 3 more
hours.

Participants will be admitted in day-care while they will receive intravenous
treatment with atosiban. They will be asked to keep a menstrual diary for one
month, one time before the treatment and another time afterwards. Besides
participants will be asked to fill in questionnaires on quality of life and
their medical history. Their pain-scores will be taken at several time points.
We will take blood samples at the start and at the end of the treatment. The
most important risk for participants is the risk on side effects related to
atosiban. Side effect include nausea (>10%) headache, dizziness, flushes,
tachycardia, hypotension, vomiting, hypoglycaemia and local reaction on the
place of injection (1-10%). The most severe side effect described is pulmonary
oedema. This was mostly in combination with other tocolytic agents and very
rare, the side effects are generally considered to be mild. Atosiban has been
administered on a routine basis to pregnant women in the same regimen as we
will use now. However we will administer atosiban for a shorter period of time.
According to the risk classification of the NFU (The Netherlands Federation of
University Medical Centres) for patients participating in this study, the risk
has been assessed as "moderate".