Liver Safety Assessment During Ulipristal Acetate Treatment for Uterine Fibroids

INTRODUCTION Fibroids are benign monoclonal tumors originated from genetically predisposed uterine smooth muscular cells in a proper hormonal environment. Fibroid growth is dependent on the ovarian steroids estrogen and progesterone. In vivo models have shown that progesterone and the presence of its receptor are the main key points for fibroid growth, being PR stimulation the primary action of estrogens.

Multiple treatment options are currently available, including surgery (hysterectomy or myomectomy), uterine artery embolization, cryomyolysis, radiofrequency myolysis, high-intensity focused ultrasound, and pharmacological treatment. Proper counseling about all therapeutic approaches should be discussed with the patient, explaining pros and cons of every treatment and taking into consideration several clinical factors such as number, location and fibroid size, age and desire for future pregnancies. Final decision of the best treatment should be taken according to the patient's desire.

Uterine fibroids still represent the most frequent indication for hysterectomy, which associates a low but significant risk of vascular, intestinal and urinary complications. Non-surgical treatments represent a good option for those young patients in order to avoid surgical scars on uterine surface and the risk of hysterectomy. Due to the Es and Prog dependent status, fibroid-related symptoms often cease once menopause status is achieved, so selected perimenopausal patients could also benefit from those therapies and avoid a surgery.

Among the pharmacological treatment options, gonadotropin-releasing hormone agonists (GnRHa) are effective in reducing bleeding and uterine volume, but with considerable side-effects due to the estrogen-suppression status. Ulipristal acetate (UPA) have been shown to be effective in bleeding control, induction of amenorrhea and fibroid reduction when compared to GnRHa, with fewer side effects as it maintains estradiol at mid-follicular phase levels. Pre-surgical UPA treatment allows recovery of Hb levels and reduction in fibroid size, allowing better minimally invasive surgery procedures. On selected patients, long-term intermittent treatment with UPA offers an alternative to surgery allowing patients to reach menopause status without surgery.

In February 2018, the European Medicines Agency (EMA) announced temporary restrictive measures to UPA treatment as 8 cases of severe liver injury were potentially linked to UPA administration. After the Pharmacovigilance Risk Assessment Committee (PRAC) evaluation concluded, the association between UPA and drug induced liver injury (DILI) was neither confirmed nor excluded. As a conclusion, the EMA stated that the benefits of UPA for the treatment of symptomatic uterine fibroids clearly outweigh the risks, but risk-minimization measures were needed in order to avoid the rare but serious possible liver injury.