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Pasireotide (Signifor)8 residuesFCFWKTCTEach bubble = one amino acid. Size = residue mass. Color = chemical class.Also known as: SOM230, Signifor, Signifor LAR
Seventy-three percent of patients develop hyperglycemia. That number defines pasireotide (brand name Signifor) more than any other statistic. This cyclohexapeptide somatostatin analog binds all five SSTR subtypes, with 30- to 40-fold higher affinity for SSTR5 than octreotide. The FDA approved it in December 2012 for Cushing's disease and in 2014 as a long-acting release formulation for acromegaly. In the important Phase III trial [1], 600 to 900 mcg subcutaneous twice daily normalized urinary free cortisol in roughly 26% of patients, with meaningful cortisol reductions in over half. Endocrinologists prescribe it when pituitary surgery fails or isn't possible, and blood glucose monitoring starts before the first dose.
Thirty- to 40-fold higher SSTR5 affinity than octreotide. That receptor selectivity is the entire clinical premise behind pasireotide. Pasireotide (Signifor, SOM230, CAS 396091-73-9) is a cyclohexapeptide somatostatin analog that binds all five somatostatin receptor subtypes (SSTR1 through SSTR5). Corticotroph adenomas in Cushing's disease predominantly express SSTR5, not SSTR2. First-generation analogs like octreotide and lanreotide barely touch SSTR5; pasireotide saturates it. That difference gave Cushing's disease patients the first medical therapy proven to target the pituitary tumor directly. The Phase III trial [1] enrolled adults with persistent or recurrent Cushing's disease and tracked urinary free cortisol. At 600 to 900 mcg subcutaneous twice daily, approximately 26% achieved UFC normalization by six months. Over 50% had meaningful reductions even without full normalization. A 2025 real-world monocentric cohort of 19 patients [2] pushed that number to 52.6% normalization, suggesting careful patient selection matters. For acromegaly, the story is different. Signifor LAR (40 to 60 mg intramuscular every 28 days) targets patients who failed octreotide or lanreotide. The PAOLA trial [3] found 31.3% biochemical control, but a 2024 systematic review and meta-analysis (409 patients across 12 studies)[4] reported 57.9% IGF-1 control in real-world practice. That gap between trial and clinic likely reflects better responder identification over time. The limitation is metabolic. Hyperglycemia hits approximately 73% of patients because SSTR5 activation suppresses insulin and incretin secretion from pancreatic beta cells. Three of 19 patients in the 2025 cohort discontinued specifically because of glucose complications. This is a drug that works, but the metabolic cost of treatment requires aggressive co-management from day one.
Somatostatin receptors come in five subtypes. First-generation analogs like octreotide hit SSTR2 hard and mostly ignore the rest. Pasireotide flips the script. The binding profile reads: SSTR5 at IC50 of approximately 0.16 nM, SSTR2 at 1.0 nM, SSTR3 at 1.5 nM, SSTR1 at 9.3 nM (Bruns C et al.)[1]. That SSTR5 affinity is 30 to 40 times higher than octreotide. For Cushing's disease, SSTR5 is the receptor that matters because corticotroph adenomas express it far more than SSTR2. When pasireotide binds SSTR5 on corticotroph tumor cells, it activates Gi/Go-coupled inhibitory signaling. Intracellular cAMP drops. POMC gene transcription slows. ACTH secretion decreases. Less ACTH reaches the adrenals; cortisol output falls. Separately, phosphotyrosine phosphatases SHP-1 and SHP-2 activate, feeding into MAPK/ERK pathway inhibition. That arm carries antiproliferative effects on the tumor itself. In acromegaly, the mechanism shifts to dual SSTR2 and SSTR5 engagement on somatotroph adenomas. Tumors that lost SSTR2 expression (and stopped responding to octreotide) may still respond through the SSTR5 pathway. The hyperglycemia problem traces back to the same receptor. SSTR5 sits on pancreatic beta cells and enteroendocrine cells. Activation suppresses insulin secretion directly and blocks incretin hormones GLP-1 and GIP. Meanwhile, SSTR2-mediated glucagon suppression is relatively weaker with pasireotide than with octreotide. The net effect is diabetogenic.
FDA-approved for Cushing's disease (SC, 600-900 mcg BID) and acromegaly (LAR, 40-60 mg monthly IM). Pivotal Phase III trial normalized UFC in ~26% of Cushing's patients with UFC reduction in >50%; 2025 real-world monocentric cohort (n=19) showed 52.6% normalization. Acromegaly systematic review/meta-analysis (2024, n=409, 12 studies) found 57.9% IGF-1 control in first-generation SSA-resistant patients: substantially above the ~30% in RCTs, suggesting favorable real-world responder selection. Hyperglycemia (73%) is the dominant treatment-limiting adverse effect.
Phase III Cushing's trial (PMID 22455413) + acromegaly real-world meta-analysis 2024 (PMID 39527181, n=409) + PAOLA trial (PMID 25002177)
Only ~26–53% of Cushing's patients achieve UFC normalization: no validated biomarker identifies responders before treatment. Hyperglycemia in ~73% frequently requires antidiabetic therapy initiation. Cholelithiasis in up to 30% with prolonged use. QT prolongation and bradycardia require cardiac monitoring. Cost ~$62–66K/year retail with no generic or legal compounded alternative. No head-to-head data vs. cabergoline for Cushing's disease.
No off-label, self-directed, or bodybuilding community use exists: pasireotide is a prescription specialty drug used exclusively under endocrinology supervision. Patient community sentiment (r/Cushings, pituitary patient forums) centers on real-world tolerability: hyperglycemia burden is the dominant concern. Responders report meaningful symptom improvement; non-responders face difficult conversations about alternative therapies (cabergoline, osilodrostat, bilateral adrenalectomy).
Pasireotide has no off-label or community self-administration use. All efficacy and safety data comes from clinical trials and real-world medical cohorts. Community sentiment reflects patients receiving prescribed endocrinology therapy, not self-directed peptide use. There is no 'community protocol' to compare against the science.
| Level | Dose / Injection | Frequency |
|---|---|---|
| Beginner | 600mcg | 2x Daily |
| Moderate | 600mcg | 2x Daily |
| Aggressive | 900mcg | 2x Daily |
Pasireotide is not a research peptide you'll reconstitute from a lyophilized vial. Signifor SC comes as pre-filled, single-use ampules in three concentrations: 0.3 mg/mL, 0.6 mg/mL, and 0.9 mg/mL. Each ampule holds 1 mL. You draw the full contents and inject subcutaneously into the abdomen or thigh. The 600 mcg dose uses one 0.6 mg/mL ampule per injection, twice daily. The 900 mcg dose uses one 0.9 mg/mL ampule. No measuring, no bacteriostatic water, no math. Verify the ampule concentration matches your prescribed dose before each shot. Spacing matters. Doses need to be roughly 12 hours apart. Intervals stretching beyond 14 hours reduce steady-state plasma exposure and may compromise efficacy. The most common beginner mistake: ignoring blood glucose. Buy a glucometer before you start. Test fasting glucose daily for the first two weeks. If readings cross 126 mg/dL, contact your endocrinologist about starting metformin. This is not something to wait on. Store ampules at 2 to 8 degrees C. Do not freeze. Protect from light. Each ampule is single-use; discard any leftover.
Pasireotide is used as continuous long-term therapy and is not cycled. For Cushing's disease, treatment is maintained as long as clinical benefit is observed. Blood glucose must be monitored weekly for the first 2-3 months and at least quarterly thereafter.
Pasireotide is not cycled. It is continuous long-term therapy for active Cushing's disease or acromegaly. Unlike research peptides requiring receptor recovery breaks, pasireotide's therapeutic target (pituitary corticotroph or somatotroph adenoma) requires sustained receptor engagement. Discontinuation leads to return of disease activity within weeks. Some patients develop persistent glucose abnormalities that persist even after eventual discontinuation.
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Expected: UFC normalization in ~26–53% of patients. UFC reduction (without full normalization) in >50%. Improvement in clinical signs of hypercortisolism (weight loss, blood pressure normalization, skin changes) within 3–6 months in responders.
Monitor: Blood glucose: before starting + weekly for first 2–3 months + at least quarterly. UFC: baseline, 2 months, 6 months, then every 6 months. ECG: baseline and day 21. LFTs: baseline, 6 weeks, 12 weeks, then periodically. Gallbladder ultrasound: baseline and every 6–12 months. HbA1c: quarterly. Serum cortisol: monitor for adrenal insufficiency as UFC normalizes.
Confirm your prescribed dose and select the correct pre-filled ampule: 0.3 mg/mL (300 mcg), 0.6 mg/mL (600 mcg), or 0.9 mg/mL (900 mcg). Each ampule contains 1 mL of ready-to-inject solution.
Remove the ampule from refrigeration and allow it to reach room temperature for a few minutes. Clean the injection site (abdomen or outer thigh) with an alcohol swab.
Draw the full 1 mL into an insulin syringe or the provided syringe. On a standard 100-unit insulin syringe, 1 mL equals 100 units. You inject the full 100 units for every dose regardless of concentration.
Insert the needle at a 45- to 90-degree angle. A 29- to 31-gauge, 0.5-inch needle works well for subcutaneous delivery.
Withdraw the needle, apply gentle pressure with a cotton pad. Discard the ampule and syringe in a sharps container.
Administer the second daily dose approximately 12 hours later. Rotate injection sites each time: left abdomen, right abdomen, left thigh, right thigh.
Test fasting blood glucose the next morning, especially during the first two weeks of therapy.
For Signifor LAR (acromegaly): This is a clinic-only procedure. A healthcare provider reconstitutes the lyophilized microsphere kit immediately before injection and delivers 40 to 60 mg as a deep intramuscular gluteal injection every 28 days. Patients cannot self-administer the LAR formulation.
Sequential or combination therapy in refractory Cushing's disease. Cabergoline targets D2 dopamine receptors on corticotroph tumors: mechanism independent of SSTR5. Some centers add cabergoline if pasireotide achieves only partial UFC reduction. Not a standard first-line combination but used in treatment-refractory cases.
First-line antidiabetic co-prescription for pasireotide-induced hyperglycemia. Per 2024 clinical management algorithm (PMID 39735646): start when fasting glucose exceeds 126 mg/dL or HbA1c >6.5%. Does not affect pasireotide efficacy.
Metformin 500 mg BID, titrate to 1000 mg BID based on glucose response and GI tolerability. Check eGFR before starting.
Second-line antidiabetic when metformin is insufficient or poorly tolerated for pasireotide-induced hyperglycemia. GLP-1 RAs address the insulin secretion defect via a non-SSTR pathway. Per 2024 hyperglycemia management algorithm (PMID 39735646); ~25–50% of patients can achieve glucose control with oral agents alone.
Additive QT prolongation. Pasireotide independently prolongs QTc; combination dramatically increases risk of torsades de pointes. ECG monitoring mandatory when combination cannot be avoided.
Do not combinePasireotide is a weak CYP3A4 inhibitor and may reduce intestinal absorption of cyclosporine. Cyclosporine blood levels may fall, risking transplant rejection. Monitor drug levels closely if co-administration required.
Additive bradycardia. Pasireotide slows heart rate via somatostatin receptor effects on the sinoatrial node; combination may cause clinically significant bradycardia or heart block.
Pasireotide profoundly suppresses insulin and incretin secretion. Patients on insulin before pasireotide initiation require close monitoring as glucose dynamics change significantly. Insulin requirements may increase, then fluctuate as antidiabetic regimen is adjusted.
Pricing updated 2026-04-09
Hyperglycemia. Not the mild, transient kind. Pasireotide causes clinically significant glucose elevation in approximately 73% of patients, often requiring initiation of antidiabetic therapy in people who were not diabetic before starting treatment. The mechanism is direct: SSTR5 suppresses insulin secretion from pancreatic beta cells and inhibits incretin hormones GLP-1 and GIP. Three of 19 patients in a 2025 real-world cohort [2] had to stop pasireotide entirely because of glucose complications. Blood glucose monitoring is not a suggestion. It starts before the first injection and continues weekly for the first two to three months. The management algorithm (per 2024 clinical guidance)[6] begins with metformin 500 mg twice daily when fasting glucose exceeds 126 mg/dL. If that fails, DPP-4 inhibitors or GLP-1 receptor agonists are second-line. Approximately 25 to 50% of patients achieve glucose control with oral agents alone. The rest may need insulin. Gastrointestinal side effects are common and front-loaded. Diarrhea affects roughly 58% of patients. Nausea hits 52%. Abdominal pain occurs in about 24%. These GI effects are worst in the first two to four weeks and usually become tolerable for most people by month two. Small frequent meals and loperamide for diarrhea help during that adjustment period. Cholelithiasis develops in up to 30% of patients on prolonged somatostatin analog therapy. Somatostatin receptors reduce gallbladder contractility; bile stasis follows. Baseline gallbladder ultrasound is required, with repeat imaging every 6 to 12 months. Right upper quadrant pain warrants immediate evaluation. Asymptomatic stones can be monitored; symptomatic cholecystitis may require surgical consultation. QT prolongation is documented and requires ECG monitoring at baseline and day 21. The risk increases with concomitant QT-prolonging medications. If QTc exceeds 500 ms, the drug should be stopped. Hepatic enzyme elevations (ALT and AST) occur in 5 to 10% of patients. Liver function tests at baseline, six weeks, and 12 weeks are standard protocol. Enzymes exceeding five times the upper limit of normal require discontinuation. Injection site reactions affect about 17% of patients using the subcutaneous formulation. Rotating between abdomen and thigh helps. Bradycardia is a known class effect of somatostatin analogs. Combination with beta-blockers or non-dihydropyridine calcium channel blockers carries additive risk. One counterintuitive risk: adrenal insufficiency. As cortisol levels drop in Cushing's disease responders, the long-suppressed HPA axis may not recover fast enough. Profound fatigue, orthostatic hypotension, and nausea are the warning signs. Hydrocortisone supplementation (10 to 20 mg per day) may be needed until adrenal function recovers. Pregnancy is a contraindication. Animal studies showed embryotoxicity (Category C). Whether pasireotide passes into breast milk is unknown.
Verify Pasireotide (Signifor) dosing and safety with a second opinion
Brand-only FDA-approved product manufactured by Recordati Rare Diseases (acquired from Novartis). No legal compounding pathway exists: pasireotide is not on the FDA 503A or 503B bulk drug substance lists and has no shortage designation. Pre-filled ampules arrive quality-tested; no reconstitution quality risk for SC formulation.
| Test | When | Target |
|---|---|---|
| Blood glucose (fasting) | Before starting, daily for first 2 weeks, weekly for first 2–3 months, then at least quarterly | Fasting glucose <126 mg/dL; 2-hour postprandial <180 mg/dL |
| HbA1c | Baseline, then every 3 months for first year, then every 6 months | <7.0% for most patients; <8.0% in elderly or complex patients |
| 24-hour urinary free cortisol (UFC) | Baseline, 2 months, 6 months, then every 6 months (Cushing's disease) | Within local laboratory upper limit of normal |
| IGF-1 and random GH | Baseline and every 3 months (acromegaly) | IGF-1 within age-adjusted normal range; random GH <2.5 mcg/L |
| ECG (QTc interval) | Baseline and day 21, then as clinically indicated (especially if QT-prolonging drugs added) | QTc <450 ms (men) / <460 ms (women); stop drug if QTc >500 ms |
| Liver function tests (ALT, AST, bilirubin) | Baseline, 6 weeks, 12 weeks, then periodically | <3x ULN; hold drug if >5x ULN |
| Gallbladder ultrasound | Baseline and every 6–12 months | No new stones, sludge, or biliary dilation |
| Serum cortisol (morning) | Periodically in Cushing's patients achieving UFC normalization | Morning cortisol >5 mcg/dL to exclude adrenal insufficiency |
Hyperglycemia in ~73% of patients: early detection prevents DKA and guides antidiabetic therapy initiation
Long-term glycemic control: guides antidiabetic medication management
Primary efficacy endpoint: determines response and need for dose titration; also screens for developing adrenal insufficiency
Primary biochemical efficacy endpoints for acromegaly
QT prolongation documented in clinical trials; risk increases with electrolyte abnormalities or concomitant QT-prolonging medications
Hepatic enzyme elevations in 5–10% of patients; severe hepatic impairment requires dose adjustment or discontinuation
Cholelithiasis in up to 30% with prolonged SSA use; EudraVigilance data (PMID 39770473) shows higher hepatobiliary stone rate vs. comparator SSAs
Risk of relative adrenal insufficiency as long-suppressed HPA axis recovers; requires glucocorticoid supplementation if symptomatic
Peak plasma levels within 1-2 hours. ACTH and cortisol suppression begins within hours. GI side effects may occur early. Blood glucose may rise within hours.
Urinary free cortisol begins decreasing. Hyperglycemia typically manifests: daily blood glucose monitoring. GI side effects most prevalent but usually diminish.
Dose titration based on UFC response. Blood glucose management established with appropriate antidiabetic therapy.
UFC normalization assessed. Approximately 26% achieve normalization by 6 months; over 50% show meaningful reductions. Clinical signs of Cushing's begin improving.
Continued long-term therapy with periodic monitoring of UFC, glucose, HbA1c, liver enzymes, ECG, and gallbladder status. Tumor volume reduction may be observable on MRI.
Day 1 through 14, Initiation: Plasma levels peak within one to two hours of the first subcutaneous dose. ACTH and cortisol suppression begins within hours. Hyperglycemia typically shows up by day one to three, so daily glucose monitoring is not optional. Patients report nausea, diarrhea, and injection site soreness during this window. Most find the GI effects manageable within one to two weeks. Weeks 2 through 8, Dose titration window: UFC starts measurably declining in patients who will respond. The antidiabetic regimen gets established and stabilized. An ECG check happens at day 21. Responders begin noticing early cortisol symptom reduction: better sleep quality, the beginning of weight normalization. GI side effects subside for most patients by week four. Glucose management remains the active challenge. Months 2 through 6, Response assessment: This is the decision point. UFC normalization happens in roughly 26 to 53% of patients by six months. Over 50% show meaningful reductions even without full normalization. Clinical Cushing's features start improving: weight loss, blood pressure drops, skin changes reverse. Responders report a real quality-of-life shift. Non-responders discuss switching to cabergoline, osilodrostat, or bilateral adrenalectomy with their endocrinologist. Months 6 through 24 and beyond, Long-term maintenance: Responders stay on continuous therapy. Tumor volume reduction may show on MRI at 12 months or later. For acromegaly patients on the LAR formulation, sustained IGF-1 normalization has been documented at 36 months [5]. The ongoing reality is metabolic management: glucose monitoring, gallstone surveillance, and fatigue are the three persistent challenges. Some patients develop permanent glucose abnormalities that persist even after eventual discontinuation.
Peak plasma levels within 1–2 hours of first SC dose. ACTH and cortisol suppression begins within hours. Hyperglycemia typically manifests day 1–3. GI side effects most prominent in this window.
Patients report GI discomfort (nausea, diarrhea) and glucose spikes requiring monitoring. Injection site soreness common. Most find GI effects manageable within 1–2 weeks.
UFC begins measurably declining in responders. Antidiabetic regimen established and stabilized. Dose titration decision at 2-month UFC. ECG check at day 21.
Responders begin noticing early cortisol symptom reduction: improved sleep quality, beginning of weight normalization. GI side effects subside for most patients by week 4.
UFC normalization in ~26–53% by 6 months. Meaningful UFC reduction in >50%. Clinical Cushing's features begin improving: weight loss, blood pressure, skin changes.
Responders report significant quality-of-life improvement: weight loss, resolution of facial swelling and muscle weakness, better energy. Non-responders transition to alternative therapy. Glucose management is the primary ongoing challenge for both groups.
Sustained UFC control in responders. Possible tumor volume reduction on MRI at 12+ months. Sustained IGF-1 normalization documented at 36 months in acromegaly responders (PMID 38362280). Ongoing monitoring for all identified toxicities.
Long-term patients report stable disease control but persistent metabolic burden: established diabetes management, gallstone surveillance, and fatigue as the main ongoing challenges. Some develop permanent glucose abnormalities.
Source: FDA prescribing information; Bruns C et al. J Clin Endocrinol Metab. 2012;97(4):1096-1105. PMID: 22455413
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Pasireotide is FDA-approved under two brand names. Signifor (subcutaneous injection) received approval in December 2012 for Cushing's disease in adults who cannot undergo pituitary surgery or for whom surgery has failed. Signifor LAR (intramuscular injection) was approved in 2014 for acromegaly in patients who have not responded adequately to surgery or for whom surgery is not an option. Both are manufactured by Recordati Rare Diseases (acquired from Novartis). No generic version exists. Pasireotide is not listed on the FDA 503A or 503B bulk drug substance lists and carries no shortage designation. There is no legal compounded or gray-market alternative. The drug is available only through licensed US pharmacies with a valid prescription. WADA status: Somatostatin analogs do not appear on the current WADA prohibited list, though athletes should confirm with their governing body. This is a prescription specialty drug with no off-label or recreational use community. This content is for informational purposes only and does not constitute medical advice. Pasireotide should be prescribed and monitored exclusively by an endocrinologist experienced in treating Cushing's disease or acromegaly.
Peptide Schedule Research TeamReviewed Apr 202611 Citations
