Written by Kathleen Doheny with Maria Fleseriu, MD, FACE, and Vivien Herman-Bonert, MD
Cushing's disease, an uncommon but hard to treat endocrine disorder, occurs when a tumor on the pituitary gland, called an adenoma—that is almost always benign—leads to an overproduction of ACTH (adrenocorticotropic hormone), which is responsible for stimulating the release of cortisol, also known as the stress hormone.
Until now, surgery to remove the non-cancerous but problematic tumor has been the only effective treatment. Still, many patients will require medication to help control their serum cortisol levels, and others cannot have surgery or would prefer to avoid it.
Finally, a drug proves effective as added on or alternative to surgery in managing Cushing's disease. Photo; 123rf
New Drug Offers Alternative to Surgery for Cushing's Disease
Now, there is good news about long-term positive results achieved with pasireotide (Signifor)—the first medication to demonstrate effectiveness in both normalizing serum cortisol levels and either shrinking or slowing growth of tumors over the long term.1,2 These findings appear in the journal, Clinical Endocrinology, showing that patients followed for 36 months as part of an ongoing study had improved patient outcomes for Cushing’s disease.2
"What we knew before this extension study was—the drug will work in approximately half of the patients with mild Cushing's disease," says study author Maria Fleseriu, MD, FACE, director of the Northwest Pituitary Center and professor of neurological surgery and medicine in the division of endocrinology, diabetes and clinical nutrition at the Oregon Health and Sciences University School of Medicine.
“Pasireotide also offers good clinical benefits," says Dr. Fleseriu who is also the president of the Pituitary Society, “which includes improvements in blood pressure, other signs and symptoms of Cushing’s symptom], and quality of life.”2
What Symptoms Are Helped by Drug for Cushing's Disease?
Among the signs and symptoms of Cushing’s disease that are lessened with treatment are:3
Changes in physical appearance such as wide, purple stretch marks on the skin (eg, chest, armpits, abdomen, thighs)
Rapid and unexplained weight gain
A more full, rounder face
Protruding abdomen from fat deposits
Increased fat deposits around the neck area
The accumulation of adipose tissue raises the risk of heart disease, which adds to the urgency of effective treatment. In addition, many individuals who have Cushing’s disease also complain of quality of life issues such as fatigue, depression, mood and behavioral problems, as well as poor memory.2
As good as the results appear following the longer term use of pasireotide,2 Dr. Fleseriu admits that in any extension study in which patients are asked to continue on, there are some built-in limitations, which may influence the findings. For example, patients who agree to stay on do so because they are good responders, meaning they feel better, so they’re happy to stick with the study.
“Fortunately, for the patients who have responded to pasireotide initially, this is a drug that can be continued as there are no new safety signals with longer use," Dr. Fleseriu tells EndocrineWeb, "and when the response at the start is good, very few patients will lose control of their urinary free cortisol over time. That's a frequent marker used to monitor patient's status. For those patients with large tumors, almost half of them had a significant shrinkage, and all the others had a stable tumor size."
What Are the Reasons to Consider Drug Treatment to Manage Cushing’s Symptoms
The extension study ''was important because we didn't have any long-term data regarding patient response to this once-a-month treatment to manage Cushing's disease," she says.
While selective surgical removal of the tumor is the preferred treatment choice, the success rate in patients varies, and Cushing's symptoms persist in up to 35% of patients after surgery. In addition, recurrent rates (ie, return of disease) range from 13% to 66% after individuals experience different durations remaining in remission.1
Therefore, the availability of an effective, long-lasting drug will change the course of therapy for many patients with Cushing’s disease going forward. Not only will pasireotide benefit patients who have persistent and recurrent disease after undergoing surgery, but also this medication will be beneficial for those who are not candidates for surgery or just wish to avoid having this procedure, he said.
Examining the Safety and Tolerability of Pasireotide
This long-acting therapy, pasireotide, which is given by injection, was approved in the US after reviewing results of a 12-month Phase 3 trial.1 In the initial study, participants had a confirmed pituitary cause of the Cushing's disease. After that, the researchers added the optional 12-month open-label, extension study, and now patients can continue on in a separate long-term safety study.
Those eligible for the 12-month extension had to have mean urinary free cortisol not exceeding the upper limit of normal (166.5 nanomoles per 24 hour) and/or be considered by the investigator to be getting substantial clinical benefit from treatment with long-action pasireotide, and to demonstrate tolerability of pasireotide during the core study.1
Of the 150 in the initial trial, 81 participants, or 54% of the patients, entered the extension study. Of those, 39 completed the next phase, and most also enrolled in another long-term safety study—these results not yet available).2
During the core study, 1 participants were randomly assigned to 10 or 30 mg of the drug every 28 days, with doses based on effectiveness and tolerability. When they entered the extension, patients were given the same dose they received at month.1,2
Study Outcomes Offer Advantages in Cushing’s Disease
Of those who received 36 months of treatment with pasireotide, nearly three in four (72.2%) had controlled levels of urinary free cortisol at this time point.2 Equally good news for this drug was that tumors either shrank or did not grow. Of those individuals who started the trial with a measurable tumor (adenoma) as well as those with an adenoma at the two year mark (35 people), 85.7% of them experienced a reduction of 20% or more or less than a 20% change in tumor volume. No macroadenomas present at the start of the study showed a change of more than 20% at either month 24 or 36.2
Improvements in blood pressure, body mass index (BMI) and waist circumference continued throughout the extension study.1 Those factors influence CVD risk, the leading cause of death in those with Cushing's.4
As for adverse events, most of the study participants, 91.4%, did report one or more complaint during the extension study—most commonly, it was high blood sugar, which was reported by nearly 40% of participants.2. This is not surprising when you consider that most (81.5%) of the individuals participating in the extension trial entered with a diagnosis of diabetes or use of antidiabetic medication, and even more of them (88.9%) had diabetes at the last evaluation.1
This complication indicates the need for people with Cushing’s disease to check their blood glucose, as appropriate.
Do You Have Cushing’s Disese? Here's What You Need to Know
Women typically develop Cushing’s disease more often than men.
What else should you be aware of if you and your doctor decide this medication will help you? Monitoring is crucial, says Dr. Fleseriu, as you will need to have your cortisol levels checked, and you should be on alert for any diabetes signals, which will require close monitoring and regular follow-up for disease management.
Another understanding gained from the results of this drug study: "This medication works on the tumor level," she says. "If the patient has a macroadenoma (large tumor), this would be the preferred treatment." However, it should be used with caution in those with diabetes given the increased risk of experiencing high blood sugar.
The researchers conclude that "the long-term safety profile of pasireotide was very favorable and consistent with that reported during the first 12 months of treatment. These data support the use of long-acting pasireotide as an effective long-term treatment option for some patients with Cushing's Disease."1
Understanding Benefits of New Drug to Treat Cushing's Diseease
Vivien S. Herman-Bonert, MD, an endocrinologist and clinical director of the Pituitary Center at Cedars-Sinai Medical Center in Los Angeles, agreed to discuss the study findings, after agreeing to review the research for EndocrineWeb.
As to who might benefit most from monthly pasireotide injections? Dr. Herman-Bonert says, "any patient with Cushing's disease that requires long-term medical therapy, which includes patients with persistent or recurrent disease after surgery." Certainly, anyone who has had poor response to any other medical therapies for Cushing's disease either because they didn't work well enough or because the side effects were too much, will likely benefit a well, she adds.
Among the pluses that came out of the study, she says, is that nearly half of the patients had controlled average urinary free cortisol levels after two full years, and 72% of the participants who continued on with the drug for 36 months were able to remain in good urinary cortisol control .1
As the authors stated, tumor shrinkage was another clear benefit of taking long-term pasireotide. That makes the drug a potentially good choice for those even with large tumors or with progressive tumor growth, she says. It’s always good for anyone with Cushing’s disease to have an alterative to surgery, or a back-up option when surgery isn’t quite enough, says Dr. Herman-Bonert.
The best news for patients is that quality of life scores improved,1 she adds.
Dr Herman-Bonert did add a note of caution: Although the treatment in this study is described as ''long-term, patients will need to be on this for far longer than 2 to 3 years," she says. So, the data reported in this study may or may not persist, and we don’t yet know what the impact will be 10 or 25 years out.
Also, the issue of hyperglycemia-related adverse events raises a concern, given the vast majority (81%) of patients who have both Cushing’s disease and diabetes. Most of those taking this drug had a dual diagnosis—having diabetes, a history of diabetes, or taking antidiabetic medicine.
If you are under care for diabetes and you require treatment for Cushing’s disease, you must be ver mindful that taking pasireotide will likely lead to high blood sugar spikes, so you should plan to address this with your healthcare provider.
Dr. Fleseriu reports research support paid to Oregon Health & Science University from Novartis and other 0companies and consultancy fees from Novartis and Strongbridge Biopharma. Dr. Herman-Bonert has no relevant disclosures.
The study was underwritten by Novartis Pharma AG, the drug maker.