Comprehensive medication guide to Hemgenix Kit 126-130 kg including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
$0 out-of-pocket for most commercially insured patients through CSL Behring's HEMGENIX Connect Copay Support Program (subject to terms and conditions). Hemgenix is covered under the medical benefit (not pharmacy benefit). Medicare Part B covers Hemgenix for eligible beneficiaries with 20% coinsurance after the Part B deductible. Government insurance patients (Medicare, Medicaid) are not eligible for the commercial copay support program but may access other assistance programs.
Estimated Cash Pricing
Hemgenix has a list price of approximately $3.5 million for a one-time dose — the most expensive single-use medicine in the United States as of 2026. This price covers the entire gene therapy treatment; no ongoing drug purchases are required. No GoodRx or retail coupon pricing applies, as Hemgenix is not dispensed at retail pharmacies.
Medfinder Findability Score
20/100
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Hemgenix (etranacogene dezaparvovec-drlb) is a one-time gene therapy for adults with hemophilia B (congenital Factor IX deficiency), approved by the FDA on November 22, 2022. It is the first and currently the only FDA-approved gene therapy for hemophilia B. The Kit 126-130 kg designation refers to the patient-specific, weight-based dosing kit dispensed for patients in this weight range.
Manufactured and commercialized by CSL Behring (developed originally by uniQure), Hemgenix is indicated for adult males with moderately severe to severe hemophilia B who currently use Factor IX prophylaxis, have experienced life-threatening hemorrhage, or have repeated serious bleeding episodes. A single IV infusion delivers a working copy of the Factor IX gene to liver cells using an AAV5 viral vector, enabling the body to produce its own clotting factor for years.
Important 2026 update: In March 2026, CSL Behring announced a temporary global stockout of Hemgenix due to manufacturing complexity. This is not a safety issue. Patients should contact HEMGENIX Connect (1-833-436-0021) for the latest supply information.
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Hemgenix uses an adeno-associated virus serotype 5 (AAV5) vector to deliver a codon-optimized Padua variant of the human Factor IX gene (hFIX598 Padua) to liver cells (hepatocytes). The Padua variant produces a form of Factor IX that is approximately 8 times more active than the standard wildtype protein, maximizing therapeutic effect from a single infusion.
After IV infusion, the AAV5 vector travels through the bloodstream to the liver, enters hepatocytes, and delivers the F9 gene. The liver cells use the gene instructions to produce functional Factor IX, reducing bleeding risk without ongoing infusions. The gene is expressed through a liver-specific promoter, ensuring production is targeted to the appropriate organ. It may take several weeks for Factor IX levels to rise after infusion.
In the HOPE-B Phase 3 trial, a single Hemgenix dose produced mean Factor IX activity of 39.0 IU/dL at 6 months and 36.9 IU/dL at 18 months post-infusion. A 54% reduction in annualized bleed rate was observed, and 94% of patients were able to discontinue routine prophylaxis. Five-year follow-up data continue to support durable Factor IX expression.
2 × 10¹³ gc/kg (2 mL/kg) — Suspension for IV infusion
Single-use, weight-specific kit. For 126-130 kg patients: approximately 252-260 mL total volume (plus saline diluent). Kit contains 10-48 vials.
Hemgenix is one of the most difficult medications to find in 2026. It is a limited-distribution drug, meaning it is not dispensed at retail or specialty pharmacies — it is available only at certified hemophilia treatment centers (HTCs) that have received specific CSL Behring authorization and training. As of March 2026, CSL Behring announced a temporary global stockout due to manufacturing complexity, making access even more limited.
Several factors make Hemgenix particularly hard to find: (1) Weight-specific, patient-specific kits cannot be mass-stocked. (2) AAV5 gene therapy manufacturing is highly specialized and subject to strict regulatory batch-release requirements. (3) The patient population is small (~7,250 in the U.S.), limiting manufacturing scale. (4) Geographic distribution is uneven — many areas have no certified center within driving distance.
If you need help finding a certified treatment center with Hemgenix in stock near you, medfinder contacts treatment centers on your behalf and returns results by text, saving you hours of calls.
Hemgenix is not a controlled substance and does not require DEA scheduling, but it has strict prescriber and administration requirements. It can only be prescribed by hematologists and bleeding disorder specialists practicing at CSL Behring-certified hemophilia treatment centers (HTCs). The prescribing physician must complete the mandatory pre-treatment eligibility evaluation, including Factor IX inhibitor testing and liver workup.
Qualified prescribers include:
Hematologists at certified hemophilia treatment centers
Bleeding disorder specialists at academic medical centers (e.g., Johns Hopkins, Mayo Clinic, University of Michigan)
Physicians at federally funded CDC hemophilia treatment centers (140+ centers nationwide)
Telehealth-only providers cannot prescribe Hemgenix. In-person evaluation, blood draws, and IV infusion at a certified center are all required. Telehealth may support some initial consultations, but treatment must be administered in person.
No. Hemgenix (etranacogene dezaparvovec-drlb) is not a controlled substance and is not scheduled by the DEA. It does not have abuse potential and is not subject to Schedule II–V prescribing restrictions.
However, despite not being a controlled substance, Hemgenix has extremely restricted access due to its classification as a limited-distribution drug. It can only be prescribed by specialists at certified hemophilia treatment centers and must be administered in a clinical setting with emergency response capability. Prescribing physicians must complete eligibility screening, obtain negative Factor IX inhibitor test results, and ensure patients have appropriate pre-infusion liver workup before administration.
The following adverse reactions occurred in ≥5% of patients in clinical trials:
Elevated ALT (alanine aminotransferase) — most common, occurred in ~44% of patients
Headache
Blood creatine kinase elevations
Flu-like symptoms
Infusion-related reactions (occurred in 33% of patients)
Fatigue and malaise
Elevated AST (aspartate aminotransferase)
Hepatotoxicity: Immune-mediated liver damage can occur. Weekly ALT/AST monitoring required for 3 months post-infusion; monthly for up to 1 year. Corticosteroids may be needed if ALT elevates.
Anaphylaxis/infusion reactions: Monitor during infusion and for at least 3 hours after.
Hepatocellular carcinoma risk (theoretical): Monitor high-risk patients via ultrasound and AFP for 5 years. No confirmed cases in Hemgenix recipients to date.
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Alprolix (eftrenonacog alfa)
Extended half-life recombinant Factor IX Fc fusion protein. Once-weekly prophylaxis infusion in most patients. FDA-approved 2014. Good option during Hemgenix shortage.
Idelvion (albutrepenonacog alfa)
Extended half-life albumin-FIX fusion protein by CSL Behring. Once-weekly to every 10-14 day dosing. Widely available.
Alhemo (concizumab-mtci)
Non-factor TFPI inhibitor for hemophilia B with inhibitors. Once-daily subcutaneous injection. FDA-approved December 2023.
BeneFIX (nonacog alfa)
Standard half-life recombinant FIX. Requires 2-3x weekly infusions. Long-established safety profile. FDA-approved 1997.
Prefer Hemgenix Kit 126-130 kg? We can find it.
Alcohol
majorHepatotoxic. Worsens immune-mediated liver injury post-Hemgenix; can damage transduced hepatocytes reducing Factor IX efficacy. Avoid especially in first year post-infusion.
Hepatotoxic herbal supplements (kava, comfrey, high-dose green tea extract)
majorPotentially hepatotoxic agents increase risk of serious liver injury after Hemgenix. Avoid during first year post-infusion. Disclose all supplements to hematologist.
CYP3A4 inducers (rifampin, phenytoin, carbamazepine, St. John's Wort)
moderateCan reduce plasma concentrations of corticosteroids used therapeutically to manage post-Hemgenix ALT elevations, potentially reducing their effectiveness.
CYP3A4 inhibitors (ketoconazole, certain HIV antiretrovirals, grapefruit juice)
moderateCan increase plasma concentrations of corticosteroids used post-Hemgenix, amplifying corticosteroid side effects.
Exogenous Factor IX concentrates
minorUse after Hemgenix can interfere with laboratory assessment of endogenous Factor IX activity from gene therapy. Use same assay/reagents consistently for monitoring.
Hemgenix represents one of the most significant advances in hemophilia treatment in decades. For adults with moderate-to-severe hemophilia B, a single infusion can potentially eliminate the need for weekly IV Factor IX prophylaxis — freeing patients from a treatment burden that costs $550,000–$750,000 per year. The Phase 3 HOPE-B trial showed 94% of patients could discontinue prophylaxis after one Hemgenix dose, with Factor IX levels remaining elevated at 5-year follow-up.
The primary challenge in 2026 is access — not eligibility or safety. A global stockout announced by CSL Behring in March 2026 has created delays for patients in the treatment pipeline. Patients should continue their current Factor IX regimen, complete their pre-treatment eligibility workup, and finalize insurance prior authorization so they are ready when supply is confirmed in their region.
If you need help finding which hemophilia treatment centers near you currently have Hemgenix in stock, medfinder contacts centers on your behalf and texts you the results — saving hours of phone calls.
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