Pasireotide: evidence, FDA status and research

It is an injection for Cushing's disease, where a pituitary tumor makes too much cortisol. In a trial of 162 people about one in four reached normal levels, and most had high blood sugar.

Sold for

Pasireotide is the first drug approved specifically to treat the pituitary tumor behind Cushing's disease, where earlier drugs block cortisol downstream.

Studies say

In the phase 3 trial about one in four patients at the higher trial dose reached normal cortisol at six months, and most developed high blood sugar, which is an approvable but limited result.

Why grade A. Approval for Cushing's disease rests on a randomized, double-blind phase 3 trial in 162 patients that compared two doses, with normalization of urinary cortisol as the primary endpoint. The trial lacked a placebo arm, which is common in Cushing's because untreated disease is dangerous, and response rates were modest. It is the largest prospective drug trial in the disease. ¹²

FDA. Approved. Pasireotide is sold as Signifor, a twice-daily subcutaneous injection, for adults with Cushing's disease for whom pituitary surgery is not an option or has not worked. A monthly long-acting form, Signifor LAR, is approved for acromegaly and for Cushing's disease. ²

Written from 2 cited sources. Fact-checked 2026-10-27: 16 claims checked, 0 corrected, 1 sources unreachable. Last refreshed 2026-10-27. Not physician reviewed.

What this means for you

What people take it for: Cushing's disease caused by a pituitary tumor
Can a US doctor prescribe it?: Yes, FDA approved for Cushing's disease when surgery has not worked or is not possible.
Properly tested in people?: Yes, in large controlled trials. The main trial had 162 people.

Evidence checklist

Randomised controlled trial Randomised double-blind, two doses, no placeboyes
Human study over 100 people Phase 3, 162 patientsyes
More than one research group Article does not say who ran the trialno information
Clinical outcomes, not surrogate markers Surrogate: normal urinary cortisolno
Human safety data beyond case reports Trial data: 73% had high blood sugar eventsyes

Drawn from the cited studies below. A dash means the sources give no information.

What it is

Pasireotide is a synthetic somatostatin analog, a cousin of octreotide and lanreotide, engineered to bind a wider set of somatostatin receptor subtypes. The key difference is strong binding to subtype 5, which is the receptor most abundant on the pituitary tumors that cause Cushing's disease. Novartis developed it; Recordati Rare Diseases now markets it in the United States. ¹²

Cushing's disease is excess cortisol caused by a pituitary tumor that secretes ACTH. Surgery is the first treatment, but it fails or the disease recurs in a substantial minority, and those patients had no approved drug acting on the tumor itself until pasireotide in 2012. ¹

How it works

Somatostatin receptors come in five subtypes. Octreotide binds mainly subtype 2, which is plentiful on growth hormone tumors but scarce on ACTH tumors, which is why octreotide does little in Cushing's disease. Pasireotide binds subtypes 1, 2, 3 and 5, with the highest affinity for 5. On an ACTH-secreting tumor, activating subtype 5 suppresses ACTH release, cortisol falls, and in some patients the tumor shrinks. The same broad receptor profile acts on pancreatic cells, suppressing insulin and the gut hormones that boost it, which is why high blood sugar is the signature side effect. ¹²

What human research shows

The phase 3 trial randomized 162 adults with persistent, recurrent or newly diagnosed Cushing's disease who were not surgical candidates to one of two doses of twice-daily pasireotide, double-blind, for six months, followed by open-label treatment to twelve months. The primary endpoint was normal 24-hour urinary free cortisol at month 6 without a dose increase. About 15 percent of the lower-dose group and 26 percent of the higher-dose group met it. Cortisol fell in most patients even when it did not normalize, and blood pressure, weight, cholesterol and quality of life improved in step. Patients whose cortisol was going to normalize generally showed a drop within the first two months, which the authors suggested could identify non-responders early. ¹

In acromegaly, the long-acting form was compared with octreotide LAR and produced biochemical control in a higher proportion of patients, which is the basis of that indication as described in the label. ²

Study	Model	Finding
Phase 3 Cushing's disease trial (Colao 2012)	Humans, n=162 with Cushing's disease, randomized double-blind two-dose	Urinary free cortisol normalized at six months in about 15 and 26 percent of patients at the two trial doses, with hyperglycemia-related events in 73 percent. ¹
Signifor prescribing information	FDA label	Documents the approved indications, glucose monitoring requirements and somatostatin-class warnings. ²

Safety

Hyperglycemia is the dominant problem: in the Cushing's trial, 73 percent of patients had a hyperglycemia-related adverse event and many needed new diabetes treatment. Blood sugar rises within days of starting. Otherwise the side effects resemble other somatostatin analogs: diarrhea, nausea, abdominal pain, gallstones, and slowing of the heart rate or QT interval changes. Liver enzymes can rise. The label calls for glucose monitoring before and during treatment and for periodic gallbladder ultrasound and ECG. ¹²

Because cortisol can fall below normal, especially when pasireotide is combined with other cortisol-lowering drugs, symptoms of adrenal insufficiency such as weakness and dizziness need watching. ²

Questions for your clinician

How will my blood sugar be monitored?
What is the chance of reaching normal cortisol on this drug?
Do gallbladder or heart rhythm problems matter for me?

Questions people ask

Why does pasireotide raise blood sugar so much?

It suppresses insulin release from the pancreas and also blocks GLP-1 and GIP, the gut hormones that stimulate insulin after meals. Octreotide does some of this too, but pasireotide's broader receptor binding makes the effect much stronger. Most patients in the trial needed glucose monitoring and many needed new diabetes drugs. ¹²

How is it different from octreotide?

Both are somatostatin analogs, but pasireotide binds four receptor subtypes with strong affinity for subtype 5, the one found on ACTH-secreting pituitary tumors. That gives it activity in Cushing's disease that octreotide lacks, at the price of worse effects on blood sugar. ¹

Does it cure Cushing's disease?

No. It controls cortisol while treatment continues, in a minority of patients fully and in more partially. Surgery is the only curative treatment; pasireotide is for people in whom surgery has failed or cannot be done. ¹²

How soon can you tell if it will work?

In the trial, patients who eventually normalized cortisol usually showed a clear fall within the first one to two months. Those with no early response rarely responded later, which helps avoid prolonged exposure to the side effects in people it will not help. ¹

Citations

Colao 2012, N Engl J Med: a 12-month phase 3 study of pasireotide in Cushing's disease doi.org
Recordati Rare Diseases: Signifor (pasireotide) prescribing information recordatirarediseases.com