Comprehensive medication guide to Ogsiveo including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
Commercially insured patients may pay as little as $0 per prescription with the SpringWorks CareConnections Commercial Copay Program (no income requirements). Without copay assistance, cost sharing depends on your plan's specialty tier. Medicare Part D covers Ogsiveo but out-of-pocket cost varies; the manufacturer's commercial copay card cannot be used with Medicare.
Estimated Cash Pricing
Approximately $25,000–$30,000 per month at list price for the standard 150 mg twice daily dose (specialty drug, no generic available). Most commercially insured patients pay $0 with the SpringWorks CareConnections copay program. Uninsured patients may receive free medication through the Patient Assistance Program.
Medfinder Findability Score
72/100
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Ogsiveo (nirogacestat) is a prescription medication that made history on November 27, 2023, when the FDA approved it as the first and only treatment specifically developed for adults with progressing desmoid tumors who require systemic treatment. Before Ogsiveo, there was no approved systemic therapy for this rare and often debilitating condition.
Desmoid tumors are rare, locally aggressive soft tissue tumors arising from connective tissue. Although they are technically non-cancerous (they don't spread to other organs), they can cause severe pain, restrict movement, compress nearby structures, and frequently recur after surgery. Ogsiveo is an oral tablet — taken twice daily — that belongs to a class of drugs called gamma secretase inhibitors.
Ogsiveo is manufactured by SpringWorks Therapeutics, which became a wholly owned subsidiary of Merck KGaA in July 2025. It carries NCCN Category 1 Preferred designation for systemic treatment of desmoid tumors and has received orphan drug designation given the rarity of the condition.
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Ogsiveo works by selectively blocking the gamma secretase enzyme — a protein complex that activates the Notch signaling pathway. In desmoid tumor cells, Notch signaling is overactive, continuously sending "grow and survive" signals to tumor cells. Gamma secretase is the key enzyme that releases these signals.
By blocking gamma secretase, Ogsiveo prevents the Notch intracellular domain (NICD) from being released. Without NICD reaching the cell nucleus, the growth signals stop. The result: tumor growth slows, stops, or in many patients reverses — with 41% of patients seeing measurable tumor shrinkage in clinical trials, and 76% remaining progression-free at two years.
Ogsiveo is not chemotherapy — it does not attack all rapidly dividing cells. It is a targeted therapy that specifically disrupts a molecular pathway that desmoid tumor cells depend on for growth. This mechanism also explains several of its side effects: gamma secretase and Notch signaling are active in normal tissues (including the intestinal lining and ovaries), and blocking them system-wide produces the drug's characteristic side effects such as diarrhea and ovarian toxicity.
150 mg — tablet
Standard recommended dose: 1 tablet taken orally twice daily. As of January 2025, the 150 mg tablet replaced the previous three-tablet (3 x 50 mg) regimen.
100 mg — tablet
Reduced dose for patients requiring dose modification (e.g., Grade 3-4 diarrhea, hepatotoxicity, hypophosphatemia, or hypokalemia): 1 tablet taken orally twice daily.
Ogsiveo is not in an FDA drug shortage as of 2026. However, it is a specialty-only medication — it is not available at retail pharmacies like CVS or Walgreens. It can only be dispensed through a network of specialty pharmacies. Your insurance plan typically determines which specific specialty pharmacy you can use, and prior authorization is required by virtually all payers.
The main access challenges are systemic: prior authorization delays, specialty pharmacy routing restrictions, and the high list price that draws insurer scrutiny. The 50 mg Ogsiveo tablets were discontinued in January 2025 and replaced by 100 mg and 150 mg strengths, which caused some temporary confusion within the specialty pharmacy network.
If you are having trouble locating which specialty pharmacy can fill your Ogsiveo prescription, medfinder is a paid service that calls pharmacies on your behalf and texts you the results of which ones can fill your prescription. This can save you significant time navigating specialty pharmacy networks.
Ogsiveo is not a controlled substance and does not require a DEA prescriber registration. However, insurance prior authorization criteria typically require that the prescription be written by or in consultation with an oncologist. Because desmoid tumors are rare and the drug's safety monitoring profile is complex, management by a sarcoma-experienced oncologist is strongly recommended.
Sarcoma oncologists (primary prescribers for desmoid tumors)
Medical oncologists with soft tissue tumor experience
Surgical oncologists (for referral; typically refer to medical oncology for systemic therapy)
Nurse practitioners (NPs) and physician assistants (PAs) within oncology practices (scope-of-practice dependent by state)
Initial diagnosis of desmoid tumors requires in-person examination, imaging, and tissue biopsy — this cannot be done via telehealth. However, established patients may have some follow-up appointments managed via telehealth, depending on the provider and applicable state regulations. Major cancer centers including MD Anderson, Memorial Sloan Kettering, and Mayo Clinic have dedicated sarcoma programs with extensive experience prescribing Ogsiveo.
No. Ogsiveo (nirogacestat) is not a controlled substance. It is not scheduled by the DEA and does not require a DEA prescriber registration to prescribe. Any licensed physician, nurse practitioner, or physician assistant with prescribing authority can write a prescription for Ogsiveo, as long as insurance prior authorization requirements are met.
While Ogsiveo is not a controlled substance, it does carry significant safety considerations — particularly regarding embryo-fetal toxicity (pregnancy must be avoided), ovarian toxicity in women of reproductive potential, hepatotoxicity, and electrolyte abnormalities. Regular monitoring with blood tests is required throughout treatment. Prescribing should be done by or in consultation with an oncologist familiar with the drug's safety profile.
The following side effects occurred in at least 15% of patients in the Phase 3 DeFi clinical trial:
Diarrhea (84%) — most common; Grade 3-4 in 16% of patients
Ovarian toxicity (75%) — in women of reproductive potential; 74% had recovery of ovarian function
Rash (68%)
Nausea (54%)
Fatigue (54%)
Stomatitis/mouth sores (39%)
Headache (30%)
Abdominal pain (22%), cough (20%), hair loss (19%), upper respiratory infection (17%), shortness of breath (16%)
Embryo-fetal toxicity — can cause serious fetal harm; contraception required during treatment and 1 week after last dose
Hepatotoxicity — ALT elevations in 30%, AST elevations in 33%; regular liver function monitoring required
Non-melanoma skin cancers — squamous cell carcinoma (2.9%), basal cell carcinoma (1.4%); regular skin monitoring required
Electrolyte abnormalities — hypophosphatemia and hypokalemia; regular electrolyte monitoring required
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Sorafenib (Nexavar)
A multi-targeted tyrosine kinase inhibitor used off-label in desmoid tumors. Less clinical evidence than Ogsiveo but has shown some disease stabilization in studies.
Imatinib (Gleevec)
A tyrosine kinase inhibitor used off-label in desmoid tumors. Modest response rates; some patients achieve disease stabilization, particularly those with PDGFR alterations.
Tamoxifen + Sulindac
An older combination regimen using an anti-estrogen agent and NSAID. Sometimes used as a lower-intensity option for hormonally driven or slowly progressing desmoid tumors.
Pazopanib (Votrient)
A multi-kinase inhibitor used off-label in soft tissue sarcomas including desmoid tumors when other options are unavailable or have been exhausted.
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Strong CYP3A4 inhibitors (itraconazole, ketoconazole, clarithromycin)
majorSignificantly increase nirogacestat blood levels (3–6x), raising toxicity risk. Avoid concomitant use.
Strong CYP3A4 inducers (rifampin)
majorDecrease nirogacestat levels by approximately 85%, potentially rendering treatment ineffective. Avoid concomitant use.
Proton pump inhibitors (omeprazole, lansoprazole, esomeprazole)
majorRaise stomach pH and significantly reduce nirogacestat absorption. Avoid concurrent use.
H2 blockers (famotidine, cimetidine)
moderateReduce nirogacestat absorption by raising gastric pH. Avoid if possible; antacids with timing adjustments are preferred.
Grapefruit / Seville oranges / Starfruit
majorInhibit intestinal CYP3A4, increasing nirogacestat levels. Avoid these foods entirely during treatment.
Lomitapide (Juxtapid)
majorContraindicated: nirogacestat dramatically increases lomitapide exposure through CYP3A4 inhibition.
Moderate CYP3A4 inducers (carbamazepine, cenobamate)
majorReduce nirogacestat levels by approximately 67%. Avoid concurrent use if possible.
Ogsiveo represents a landmark advancement in the treatment of desmoid tumors — a disease for which there was no approved therapy for decades. With a 41% objective response rate, 76% progression-free survival at two years, and significant improvements in patient-reported quality of life and pain, Ogsiveo offers desmoid tumor patients a meaningful new option. It is the NCCN Category 1 Preferred systemic therapy for this indication.
The primary challenges with Ogsiveo are access-related: it is a specialty-only drug with a high list price, prior authorization requirements, and distribution through a limited specialty pharmacy network. However, the SpringWorks CareConnections program provides robust support — including a $0 copay program for commercially insured patients and a Patient Assistance Program for uninsured patients.
If you need help finding which specialty pharmacy near you has Ogsiveo in stock, medfinder is a paid service that calls pharmacies on your behalf and texts you the results. We're here to help desmoid tumor patients navigate the specialty pharmacy system and get the medication they need as efficiently as possible.
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