Estriol
eMS News August 20, 2009
Estriol, a form of estrogen that pregnant women naturally produce, was first studied as a treatment for MS in 2002 after doctors noticed the benefits experienced by pregnant women. A treatment often used for pre-menopausal and menopausal women, estriol is available in a pill form.
The presumed benefit of treatment with estriol has to do with its role in suppressing the immune system. During pregnancy, the body naturally quells the immune system so that it will not misidentify the fetus as an “invader.” Because MS is an autoimmune disease, the thought is that with estriol the immune system will similarly be suppressed and therefore not attack the myelin sheaths that protect nerves.
The study of estriol as a treatment for MS is limited to women. This is because if men take estriol – or any form of the female sex hormone, estrogen – they are likely to experience breast development, hair growth, a higher voice, type II diabetes, and vision changes, among other things.
In the 2002 study that involved 12 female MS patients and included a 6-month study period, investigators measured an 80 percent reduction in gadolinium-enhancing lesions (through MRI) in the 6 patients with relapsing-remitting MS. The other participants, all with secondary progressive MS, demonstrated no improvement. The encouraging study results for those with relapsing-remitting MS have since spurred a number of larger, Phase II studies.
In 2007, a larger Phase II study was initiated. Involving 130 women with relapsing-remitting MS, the two-year study is looking at the efficacy of estriol when taken in combination with Copaxone. Study participants are being treated with either estriol or placebo along with Copaxone, and the study’s main goal is to measure patients’ relapse rate.
Although only preliminary study results have been released to date, investigators are encouraged by the potential of estriol as a combination treatment for MS. In September 2008, the study’s principal investigator, Dr. Rhonda Voskuhl, presented the preliminary results and spoke of exciting new developments regarding the role of estriol in decreasing matrix metalloproteinase (MMP). MMP is thought to be a key player in the infiltration of inflammatory cells into the central nervous system; high levels of MMP-9 are considered to be a valid way to predict the development of new active lesions. Study investigators hope to release more complete results later this year.
Although estriol is the least potent of the three types of estrogen, some side effects and risks have been documented. Side effects mostly include irregularities with menstruation. Risks associated with estriol include uterine and breast cancer (the increased levels of estriol are suspected of causing tissue stimulation, which can lead to cancer). One study also found there to be an increased risk of heart attack and stroke.