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Hemophilia B Prophylaxis Treatments Compared

Name: Hemophilia B Prophylaxis Treatments Compared
Creator: Jason Hunter
Published: 2026-10-01

4 FDA-approved drugs, side by side from the current prescribing labels. Newest label Jun 2026. Checked October 1, 2026.

TFPI blockersAlhemo · Hympavzi

Antithrombin silencerQfitlia

One-time gene therapyHemgenix

Four non-factor options are FDA-approved to prevent bleeds in hemophilia B. Three are injections under the skin at home: Alhemo once a day, Hympavzi once a week, and Qfitlia as few as 6 times a year. The fourth, Hemgenix, is a one-time gene therapy infusion for adults that in its trial cut bleeds from 4.1 a year on factor IX prophylaxis to 1.9 a year. Alhemo, Hympavzi and Qfitlia are the same drugs approved for hemophilia A; Hemgenix is hemophilia B only. Beqvez, a second gene therapy approved in 2024, was discontinued by Pfizer in 2025.

Side by side

4 approved hemophilia B treatments at a glance

How each drug is given, how often, who it is approved for and when it was first approved, from the current FDA label.

Hemophilia B treatments compared: route, schedule, approved use and approval date
Drug	How it is given	How often	Approved for	First approved
Alhemo concizumab-mtci Novo Nordisk	Under-the-skin injection with a prefilled pen, once a day	1 mg/kg loading dose on day 1, then 0.2 mg/kg once daily; dose adjusted to 0.15 or 0.25 mg/kg after a blood level check at week 4	Hemophilia B, with or without factor IX inhibitors, age 12 and older, to prevent bleeds	December 20, 2024
Hympavzi marstacimab-hncq Pfizer	Under-the-skin injection with a prefilled pen or syringe, once a week	300 mg loading dose, then 150 mg once weekly (age 12 and up); 150 mg then 75 mg weekly for ages 6 to 11. Can be raised to 300 mg weekly if bleeds continue	Hemophilia B, with or without factor IX inhibitors, age 6 and older, to prevent bleeds	October 11, 2024
Qfitlia fitusiran Sanofi (Genzyme); discovered by Alnylam	Under-the-skin injection with a prefilled pen, as few as 6 times a year	50 mg once every 2 months to start; dose and timing adjusted (10 to 50 mg, every 1 or 2 months) to keep antithrombin activity at 15% to 35%	Hemophilia B, with or without factor IX inhibitors, age 12 and older, to prevent bleeds	March 28, 2025
Hemgenix etranacogene dezaparvovec-drlb CSL Behring (developed with uniQure)	One-time IV infusion at a treatment centerAbout 60 minutes per dose	Single dose of 2 x 10^13 genome copies per kg, infused once at 500 mL per hour; never repeated	Adults with hemophilia B who use factor IX prophylaxis, or have had life-threatening or repeated serious spontaneous bleeds	November 22, 2022

The calendar

A year on each hemophilia B treatment

Every dose in a year, drawn to the label schedule, so the difference between a daily pill and a twice-yearly infusion is the picture.

Alhemo

Injection, at home

365 doses a year

Hympavzi

Injection, at home

52 doses a year

Qfitlia

Injection, at home

6 doses a year

Hemgenix

One-time gene therapy, at a clinic

Given once

Counts follow the label schedule for a full year on the maintenance dose. Drugs given in cycles or adjusted to blood tests have no fixed count, so their schedule is written out instead.

The evidence

What the pivotal hemophilia B trials showed

The primary result from the trial each FDA approval rests on, as reported on the label.

Hemophilia B pivotal trial results by drug
Drug	Pivotal trial	Primary result
Alhemo concizumab-mtci Novo Nordisk	explorer8 (no inhibitors), 156 people, 66 with hemophilia B; explorer7 (inhibitors), 133 people, 53 with hemophilia B Trial record or paper	Hemophilia B without inhibitors: 3.1 treated bleeds per year on Alhemo vs 14.8 with no prophylaxis (79% lower). With inhibitors (A and B pooled): 1.7 vs 11.8 (86% lower)
Hympavzi marstacimab-hncq Pfizer	BASIS, 116 people without inhibitors (25 with hemophilia B) and 48 with inhibitors; BASIS KIDS, 57 children Trial record or paper	No inhibitors (A and B pooled): 3.2 treated bleeds per year on Hympavzi vs 39.9 on on-demand factor (92% lower); 5.1 vs 7.9 for people switching from factor prophylaxis. With inhibitors: 1.4 vs 19.8 on on-demand bypassing agents (93% lower)
Qfitlia fitusiran Sanofi (Genzyme); discovered by Alnylam	ATLAS-A/B (no inhibitors), 120 people, 27 with hemophilia B; ATLAS-INH (inhibitors), 57 people, 12 with hemophilia B; results use the ATLAS-OLE extension Trial record or paper	No inhibitors (A and B pooled): 9.0 treated bleeds per year on Qfitlia vs 31.4 on on-demand factor (71% lower). With inhibitors: 5.1 vs 19.1 on on-demand bypassing agents (73% lower)
Hemgenix etranacogene dezaparvovec-drlb CSL Behring (developed with uniQure)	HOPE-B (NCT03569891), 54 adult men Trial record or paper	1.9 bleeds per year in months 7 to 18 after Hemgenix vs 4.1 during the 6-month lead-in on factor IX prophylaxis (ABR ratio 0.46, non-inferior); 63% had zero bleeds vs 26% before

Safety

Hemophilia B treatment side effects and warnings

Qfitlia carries a boxed warning, the FDA's strongest. The rest list their main precautions.

Hemophilia B treatments: most common side effects and key warnings from the FDA labels
Drug	Most common side effects	Key warning
Alhemo concizumab-mtci Novo Nordisk	injection site reactions 7% to 18%, headache 7% and hives (urticaria) 6%	No boxed warning. Blood clots (1.9% in trials), allergic reactions, and raised clotting lab markers (D-dimer).
Hympavzi marstacimab-hncq Pfizer	injection site reactions 12%, headache 7% and fever 6%	No boxed warning. Blood clots (0.8% in the extension study), allergic reactions, possible harm to an unborn baby.
Qfitlia fitusiran Sanofi (Genzyme); discovered by Alnylam	viral infections 29%, common cold symptoms (nasopharyngitis) 26% and bacterial infections 11%	Boxed warning Boxed warning: blood clots and gallbladder disease. Also liver injury; monthly liver tests for at least 6 months, antithrombin blood tests to set the dose.
Hemgenix etranacogene dezaparvovec-drlb CSL Behring (developed with uniQure)	raised creatine kinase 42%, raised liver enzyme AST 42% and raised liver enzyme ALT 40%	No boxed warning. Infusion reactions (monitor 3 hours after), liver toxicity needing weekly liver tests for 3 months, possible long-term liver cancer risk; not for people with factor IX inhibitors.

No longer available: Beqvez (fidanacogene elaparvovec-dzkt), approved April 26, 2024, discontinued. NO LONGER AVAILABLE.

Cost

Help paying for hemophilia B treatment

Drugmaker copay and free-drug programs, plus charity funds for the condition, checked every week.

Questions

Hemophilia B treatment questions people ask

Is there a gene therapy for hemophilia B?

Yes. Hemgenix (etranacogene dezaparvovec), approved November 22, 2022, is a one-time IV infusion for adults with hemophilia B who use factor IX prophylaxis or have serious bleeding. In its trial, bleeds fell from 4.1 a year during the lead-in on factor IX to 1.9 a year in months 7 to 18 after the infusion. Beqvez, a second gene therapy approved in April 2024, was discontinued by Pfizer in February 2025.

Which hemophilia B prophylaxis is given least often?

Apart from the one-time gene therapy Hemgenix, Qfitlia is the least frequent at as few as 6 injections a year, adjusted by antithrombin blood tests. Hympavzi is weekly and Alhemo is daily.

Can Hemlibra be used for hemophilia B?

No. Hemlibra mimics factor VIII and is approved for hemophilia A only. The non-factor drugs approved for both A and B are Alhemo, Hympavzi and Qfitlia.

Which hemophilia B drugs cover inhibitors?

Alhemo, Hympavzi and Qfitlia all cover people with factor IX inhibitors on their current labels. Hemgenix excludes anyone with factor IX inhibitors.

Go deeper

More on Hemophilia B at Trial Friend

Sources

Where every number on this page comes from

Approved-drug facts are from the current FDA prescribing information on DailyMed, with the label's effective date. Investigational-drug facts are from ClinicalTrials.gov and the sources named in each row.

Alhemo (concizumab-mtci) prescribing information, Novo Nordisk, label dated Jul 2025. DailyMed. Pivotal trial: ClinicalTrials.gov
Hympavzi (marstacimab-hncq) prescribing information, Pfizer, label dated Jun 2026. DailyMed. Pivotal trial: ClinicalTrials.gov
Qfitlia (fitusiran) prescribing information, Sanofi (Genzyme); discovered by Alnylam, label dated Sep 2025. DailyMed. Pivotal trial: ClinicalTrials.gov
Hemgenix (etranacogene dezaparvovec-drlb) prescribing information, CSL Behring (developed with uniQure), label dated May 2026. DailyMed. Pivotal trial: ClinicalTrials.gov

This page compares what the FDA labels and pivotal trials report. It is not medical advice, and no trial on this page compared these drugs with each other. Written and checked by Jason Hunter; the method is on the editorial standards page.