Higher Doses of ‘Abortion Pill’ Safe in Cushing’s?

Reviewed by Zalman S. Agus, MD; Emeritus Professor, Perelman School of Medicine at the University of Pennsylvania

LAS VEGAS — Higher doses of mifepristone for Cushing’s disease (Korlym) weren’t associated with increases in serious adverse events, researchers reported here.

Korlym is a glucocorticoid receptor antagonist better known as RU-486, or the “abortion pill.” It was approved for treating hyperglycemia associated with Cushing’s disease in 2012.

In an analysis of data from the SEISMIC trial, Dat Nguyen, MD, and colleagues found that similar percentages of patients had serious adverse events across all doses of the drug, reported.

They also reported at the American Association of Clinical Endocrinologists meeting here, that the proportion of the four most common adverse events — headache, fatigue, nausea, and hypokalemia — fell off after 10 weeks of the 24-week trial.

“Recent prescription data indicate that many physicians are not titrating beyond 300 mg per day, potentially limiting patients’ clinical response,” the researchers said.

The 2012 approval was based on the SEISMIC study, which followed 50 Cushing’s disease patients over 24-weeks in an open-label format. It found that daily doses improved blood sugar control and reduced insulin requirements.

Clinicians participating in the trial were told they could titrate beyond the starting dose of 300 mg a day. To look at the relationship between dose and safety, as well as response, Nguyen and colleagues looked at data on 40 of the patients who responded to therapy.

Most of them (90%) were taking at least 600 mg a day, 68% were taking at least 900 mg per day, and 44% took 1,200 mg daily.

Most of the responders (85%) had their initial clinical response at a dose of at least 600 mg daily.

Overall, there were 26 serious adverse events:

  • 10 at the 300 mg dose
  • 8 at the 600 mg dose
  • 3 at the 900 mg dose
  • 3 at the 1200 mg dose
  • 2 while off drug

 

When the researchers adjusted for the number of patients who had ever reached a given dose, the frequency of serious adverse events was similar across doses:

  • 10% of patients at 300 mg
  • 16% of patients at 600 mg
  • 15% of patients at 900 mg
  • 14% of patients at 1200 mg

 

The four most common adverse events decreased after week 10 – although that tracked an increase in dose (mean 588 mg/day before week 10 versus 895 mg/day thereafter).

Nguyen and colleagues concluded that higher doses of mifepristone weren’t associated with increases in serious adverse events or in the most common adverse events – and that better response was seen with higher doses.

Korlym was developed by Corcept Therapeutics of Menlo Park, Calif., as an orphan drug given that it is is believed only 5,000 patients are eligible for treatment. That gave the company 7 years of exclusive rights to market the agent for Cushing’s disease.

The label limits the drug’s indication to patients with endogenous Cushing’s disease who have type 2 diabetes or glucose intolerance and aren’t candidates for surgery, or failed to respond to surgical intervention.

The drug doesn’t reduce cortisol production but prevents it from binding to its receptor – an action separate from its blockade of the progesterone receptor, which makes it an effective agent in abortion.

Since the daily doses are in the same range as those used to induce abortion, the drug is contraindicated in pregnant women. It also carries a boxed warning that the drug will terminate a pregnancy.

From http://www.medpagetoday.com/MeetingCoverage/AACE/45790

Long-term mifepristone associated with endometrial thickening, bleeding

SAN FRANCISCO – Long-term mifepristone therapy for Cushing’s syndrome was associated with endometrial thickening, with some women showing histologic changes consistent with progesterone receptor modulator–associated endometrial changes, in two studies of a total of 35 patients.

The women received 300-1,200 mg/day of mifepristone in the 24-week open-label Study of the Efficacy and Safety of Mifepristone in the Treatment of Endogenous Cushing’s Syndrome (SEISMIC) and in an extension of the study in 18 patients who continued for a median of 27 months (range, 14-43 months).

Mifeprex is used, with misoprostol, to end an early pregnancy (within 49 days of the start of a woman’s last menstrual period), according to the Food and Drug Administration’s website. The treatment of Cushing’s syndrome is an off-label use.

Transvaginal ultrasounds in 26 women at baseline and 27 women after the start of the study showed that mifepristone use was associated with endometrial thickening, especially in premenopausal women. The endometrium thickened by more than 5 mm in 8 of 26 premenopausal women (31%) and in two of nine postmenopausal women (22%), with thickening of more than 10 mm in 4 premenopausal women (15%) and one postmenopausal woman (11%), Dr. Ty Carroll reported.

Four (22%) of the 18 women in the extension study who’d been on mifepristone for 14 or more weeks and who had endometrial thickening greater than 20 mm developed clinically relevant endometrial bleeding and underwent hysterectomy (three patients) or dilation and curettage. The endometrial thickening ranged from 25 to 55 mm in these women, who remained on mifepristone therapy throughout the studies, Dr. Carroll and his associates reported in a featured poster presentation at the annual meeting of the Endocrine Society.

“Gynecologic consultation may be required in patients with persistent endometrial bleeding,” said Dr. Carroll of the Medical College of Wisconsin, Milwaukee.

Vaginal bleeding of any kind occurred in 10 premenopausal women (38.5%) and two postmenopausal patients (7%). Three premenopausal women reported minor bleeding upon starting mifepristone, and one premenopausal woman reported minor bleeding after stopping mifepristone. Two premenopausal and two postmenopausal women reported intermittent, self-limited spotting or bleeding during treatment.

Bleeding did not always occur following endometrial thickening. Three patients with endometrial thickening greater than 20 mm after 6 months reported no bleeding.

Mifepristone use was not associated with precancerous endometrial lesions. In 33 endometrial biopsies obtained from 15 patients (11 premenopausal and 4 postmenopausal women), 31 biopsies (94%) had benign histology with variable findings of inactive, atrophic, disordered, or mixed-pattern endometrium, and 18 biopsies (56%) showed findings of progesterone receptor modulator–associated endometrial changes. Simple hyperplasia in one patient could not be confirmed on a repeat biopsy, and complex atypical endometrial hyperplasia in a second patient was thought to have existed prior to the study, Dr. Carroll reported. No patients showed evidence of endometrial carcinoma.

Previous studies have reported progesterone receptor modulator–associated endometrial changes from the use of mifepristone, a competitive progesterone receptor antagonist, in doses of 5-200 mg/day that are not associated with glucocorticoid receptor antagonism.

In the current study, median endometrial thickness for the premenopausal women was 5 mm at baseline and 11 mm at 6 months, and for postmenopausal women, was 3 mm at baseline and 6.4 mm at 6 months. The gain was statistically significant for premenopausal but not postmenopausal women. Endometrial thickness continued to increase in the extension study.

The SEISMIC study included adult females with endogenous Cushing’s syndrome and type 2 diabetes or impaired glucose function and/or hypertension. It excluded premenopausal women with an endometrial thickness greater than 20 mm, postmenopausal women with an endometrial thickness greater than 5 mm, patients with ovarian cysts with diameters measuring greater than 5 cm (premenopausal) or 2 cm (postmenopausal), or women with free fluid pockets greater than 4 cm. Premenopausal participants had a mean age of 39 years, and postmenopausal participants had a mean age of 57 years.

Dr. Carroll has been a speaker and researcher for Corcept Therapeutics, which markets mifepristone. His coinvestigators were employees, contractors, or consultants for Corcept, which provided some funding for the study.

By: SHERRY BOSCHERT, Clinical Endocrinology News Digital Network

sboschert@frontlinemedcom.com

On Twitter @sherryboschert

From Clinical Endocrinology News

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