Fibroids Medications

Although research shows that around a third of women develop fibroids at some point in their lives, there are few non-surgical options available to patients. Recently, however, there has been a surge in development of new uterine fibroid medications designed to help patients manage and treat the condition.

What is Esmya?

Ulipristal acetate, brand name Esmya, is a selective progesterone receptor modulator used to treat moderate to severe uterine fibroids. Esmya 5 mg was approved by the European Medical Association (EMA) in 2012 for short-term, preoperative use, and again in 2015 for longer-term, intermittent use. The drug is currently in the Food & Drug Administration’s review process pending U.S. approval.

How does it work? 

The fibroid medication esmya works by blocking progesterone receptors.

Ulipristal acetate and other selective progesterone receptor modulators work by blocking the receptor of progesterone. Progesterone is a hormone that is released by the ovaries and helps regulate the growth of the endometrium, the lining of the womb. In some cases, higher levels of progesterone can cause uterine fibroids to grow. When the progesterone receptor is blocked, fibroids that have previously been “fed” by progesterone start to shrink. In many women, related side effects, such as heavy menstrual bleeding and pelvic discomfort, also diminish. 

What do we know from previous trials?

In Europe and the United States, two major studies have been conducted to determine Esmya’s efficacy. A European series of trials called the PEARL trials used a double-blind, randomized study model to assess Esmya’s impact on patients. PEARL 1 and PEARL 2 demonstrated Esmya’s efficacy when compared to a placebo and highlighted its fewer side effects in comparison to similar drugs. The subsequent trials, PEARL 3 and PEARL 4, demonstrated the safety of Esmya for repeated use.  The PEARL studies also revealed that patients taking Esmya experienced some uncommon, non-life-threatening side effects, such as drug hypersensitivity. The EMA used these trials to evaluate and approve Esmya for short-term and long-term use.

Allergan, the U.S. drug company that submitted Esmya to the FDA, also gave the FDA access to data from the VENUS trials, another set of double-blind randomized trials. The VENUS studies have been completed, but the detailed findings have not been released to the public.

Recent Complications and Questions 

Recently, cases of Esmya patients suffering from post-treatment liver damage have begun to surface. So far, four women have reportedly suffered serious liver damage, and three of these women have had to undergo a liver transplant. In light of these complications, the EMA launched an investigation into Esmya and its potential health risks. On May 18, the EMA’s Pharmacovigilance Risk Assessment Committee (PRAC) issued a statement concluding that “Esmya may have contributed to the development of some cases of serious liver injury.” The committee also issued a number of precautionary recommendations intended to protect patients from liver injury, including a warning to patients with liver problems not to take the medication, and the implementation of regular checks on the liver health of patients currently taking Esmya. The PRAC’s decisions are not yet legally binding as the European Medicines Agency’s regulatory process is still underway, but it is important for women in the U.S. to be aware of emerging research and developments.

After the EMA investigation began, the FDA adjusted its review process. Officials have moved back their drug evaluation deadline from May to August. Until both the EMA and FDA are able to reach a verdict, questions of Esmya safety and its usefulness to patients will continue to hang in the air.


Despite these setbacks, the NWHN is encouraged by the number of companies investing in the creation of medications for uterine fibroids. Each new development brings researchers one step closer to a potential solution, and brings patients one step closer to receiving the care they deserve. The NWHN will continue to track the progress of Esmya and other emerging uterine fibroids medications so that we can empower patients with the information they need to make the best decisions about their own health.