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Study to Test the Safety and How Well Patients With Severe Hemophilia A Respond to Treatment With BAY 2599023 (DTX 201), a Drug Therapy That Delivers a Healthy Version of the Defective Factor VIII Gene Into the Nucleus of Liver Cells Using an Altered, Non-infectious Virus (AAV) as a "Shuttle"

A Phase 1/2 Open-label Safety and Dose-finding Study of BAY2599023 (DTX201), an Adeno-associated Virus (AAV) hu37-mediated Gene Transfer of B-domain Deleted Human Factor VIII, in Adults With Severe Hemophilia A

Status
Active, not recruiting
Phases
Phase 1Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03588299
Enrollment
11
Registered
2018-07-17
Start date
2018-11-07
Completion date
2026-09-15
Last updated
2026-07-06

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Hemophilia A

Keywords

Severe hemophilia A (<1% FVIII activity), Factor VIII gene therapy

Brief summary

In this study researchers want to gather more information about safety and effectiveness of BAY 2599023 (DTX201), a drug therapy that delivers the human factor VIII gene into the human body by use of a viral vector to treat the disease. By replacing the defective gene with a healthy copy the human body may produce clotting factor on its own. Hemophilia A is a bleeding disorder in which the human body does not have enough clotting factor VIII, a protein that controls bleeding. Researcher want to find the optimal dose of BAY 2599023 (DTX201) so that the body may produce enough clotting factor on its own.

Interventions

DRUGBAY2599023 (DTX201)

Single escalating doses with 4 dose steps; Single intravenous (IV) administration.

Sponsors

Bayer
Lead SponsorINDUSTRY
Ultragenix pharmaceutical
CollaboratorUNKNOWN

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
MALE
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* Males age 18 years or older. * Confirmed diagnosis of hemophilia A as evidenced by their medical history with plasma FVIII activity levels \< 1% of normal or at screening. * Have \>150 exposure days (EDs) to FVIII concentrates (recombinant or plasma-derived). If on prophylaxis, are required to be willing to stop prophylactic treatment at specified time points throughout the study or If on-demand: should have had \> 4 bleeding events in the last 52 weeks \- Agree to use reliable barrier contraception.

Exclusion criteria

* History of allergic reaction to any FVIII product. * Clinically relevant findings in the physical examination considered critical by the treating physician, including obesity with BMI \> 35 kg/m\*2 * Current evidence of measurable inhibitor against factor VIII, prior history of inhibitors to FVIII protein or clinical history suggestive of inhibitor. * Evidence of active hepatitis B or C. * Currently on antiviral therapy for hepatitis B or C. * Significant underlying liver disease. * Serological evidence of HIV-1 or HIV-2 with CD4 counts ≤200/mm\*3; HIV+ and stable participants with CD4 count \>200/mm\*3 and undetectable viral load are eligible to enroll. * Detectable antibodies reactive with AAVhu37capsid. * Participant with another bleeding disorder that is different from hemophilia A (e.g., von Willebrand disease, hemophilia B). * Participated in a gene transfer trial within the last 52 weeks or in a clinical trial with an investigational product within the last 12 weeks. * Known or suspected hypersensitivity or allergic reaction to trial product(s) or related FVIII products or any component of BAY2599023 (DTX201), or a contraindication to prednisolone

Design outcomes

Primary

MeasureTime frame
Number of patients with adverse events (AEs), treatment-emergent adverse events (TEAEs), serious adverse events (SAEs) and AEs/SAEs of special interestUp to 5 years.

Secondary

MeasureTime frameDescription
Expression pattern of FVIII activity.Up to 5 yearsDetermined using both a one-stage assay and chromogenic assay.
Proportion of patients in the respective dose step, that reached an expression of FVIII above 5%At 6 months and 12 months following the IV administration of BAY2599023

Countries

Bulgaria, France, Germany, Netherlands, United Kingdom, United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Jul 7, 2026