A Study of Gene Therapy for Classic Congenital Adrenal Hyperplasia (CAH)

A Phase 1/2, First-in-Human, Open-Label, Dose-Escalation Study of the Safety and Efficacy of Gene Therapy for Congenital Adrenal Hyperplasia Through Administration of an Adeno-Associated Virus (AAV) Serotype 5-Based Recombinant Vector Encoding the Human CYP21A2 Gene

Status

Active, not recruiting

Phases

Phase 1Phase 2

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT04783181

Enrollment

Registered

2021-03-05

Start date

2021-07-01

Completion date

2029-02-28

Last updated

2025-12-23

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

Conditions

Congenital Adrenal Hyperplasia

Keywords

CAH, Gene therapy, AAV, AAV5

Brief summary

This study is designed to evaluate the safety, tolerability, and efficacy of AAV5 based BBP-631 in adult participants diagnosed with classic congenital adrenal hyperplasia.

Detailed description

Participants will receive a single dose of AAV5 based intravenous (IV) BBP-631 and will be followed for safety and efficacy for at least 5 years after the date of treatment with BBP-631.

Interventions

BIOLOGICALAAV BBP-631

intravenous

Study design

Allocation

NON_RANDOMIZED

Intervention model

SEQUENTIAL

Primary purpose

TREATMENT

Masking

NONE

Intervention model description

Participants will be assigned sequentially to one of 4 dose levels depending on the date of determination of eligibility.

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

Key Inclusion Criteria 1. Adult male and non-pregnant females with classic CAH (simple virilizing or salt-wasting) due to 21-OHD 2. Screening/baseline 17-OHP levels \> 5-10 × ULN and \< 40 × ULN (upper limit of normal) 3. Stable oral hydrocortisone (HC) regimen as the only glucocorticoid (GC) maintenance therapy 4. Naïve to prior gene therapy or AAV-mediated therapy Key

Exclusion criteria

1. Positive for anti-AAV5 (Adeno-Associated Virus Type 5) antibodies 2. History of adrenalectomy and/or significant liver disease

Design outcomes

Primary

Measure	Time frame
Number of participants with Treatment-emergent Adverse Events that Led to Study Discontinuation	up to 5 years
To select the optimum dose or dose range of BBP 631 for future studies	up to 5 years

Secondary

Measure	Time frame
Change from Baseline in 17-OHP (hydroxyprogesterone) levels	Baseline, Week 52 and through study completion, an average of 5 years
Change from Baseline in androstenedione (A4) levels	Baseline, Week 52 and through study completion, an average of 5 years
Change from Baseline in endogenous cortisol levels	Baseline, Week 52 and through study completion, an average of 5 years

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026