Cystic FibrosisPhase 1NCT07813039
A Phase 1 Relative Bioavailability Study of a VX-581 Tablet Formulation
A Phase 1 study testing VX-581 in people with Cystic Fibrosis, run by Vertex Pharmaceuticals Incorporated at 1 site in United States.
Trial summary
The purpose of this study is to evaluate the relative bioavailability of VX-581 tablet formulation compared to a suspension formulation along with its safety and tolerability. Read more about this study
- Who is it for?
- Ages 18 to 55 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Cystic Fibrosis
- What is being tested?
- VX-581
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 16 participants
- Where
- 1 siteUnited States
- Study dates
- 23 Sep 2026to 27 Oct 2026
- Phase
- Phase 1
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 55 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Body mass index (BMI) of 18.0 to 32.0 kilogram per meter square (kg/m^2), inclusive
- Total body weight of greater than (>) 50 kg
- Nonsmoker or ex-smoker for at least 3 months before screening with current nonsmoking status confirmed by urine or blood cotinine at screening
Who cannot join
- History of febrile illness or other acute illness that has not fully resolved within 14 days before the first dose of study drug
- Any condition possibly affecting drug absorption
- Other protocol defined Inclusion/Exclusion criteria may apply.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Celerion - Tempe
Tempe, Arizona, 85283
About this study
Official title: A Phase 1, Open-label, Randomized, Crossover Study to Evaluate the Relative Bioavailability of a Tablet Formulation of VX-581 in Healthy Adult Subjects
The purpose of this study is to evaluate the relative bioavailability of VX-581 tablet formulation compared to a suspension formulation along with its safety and tolerability.
Read the detailed description
The purpose of this study is to evaluate the relative bioavailability of VX-581 tablet formulation compared to a suspension formulation along with its safety and tolerability in healthy human participants. Note: This clinical trial information was submitted voluntarily under the applicable law and, therefore, certain submission deadlines may not apply. (That is, clinical trial information for this applicable clinical trial was submitted under section 402(j)(4)(A) of the Public Health Service Act and 42 CFR 11.60 and is not subject to the deadlines established by sections 402(j)(2) and (3) of the Public Health Service Act or 42 CFR 11.24 and 11.44.).
- Conditions
- Cystic Fibrosis
- Being tested
- VX-581
- Medical subject headings
- Cystic Fibrosis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
VX-581Drug
Tablet and Suspension for Oral Administration.
| Study group | Role | What they receive |
|---|---|---|
| Sequence 1 | Experimental | Participants will be randomized to receive VX-581 suspension in dosing period 1 followed by VX-581 tablet in dosing period 2. A washout period of 10 days will be maintained between the 2 dosing periods. Receives: Drug: VX-581 |
| Sequence 2 | Experimental | Participants will be randomized to receive VX-581 tablet in dosing period 1 followed by VX-581 suspension in dosing period 2. A washout period of 10 days will be maintained between the 2 dosing periods. Receives: Drug: VX-581 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Maximum Observed Plasma Concentration (Cmax) of VX-581
Measured: Period 1 and Period 2: From Day 1 up to Day 21
Area Under the Concentration Versus Time Curve (AUC) of VX-581
Measured: Period 1 and Period 2: From Day 1 up to Day 21
Secondary outcomes (1)
Safety and Tolerability as Assessed by Number of Participants With Adverse Events (AEs) and Serious Adverse Events (SAEs)
Measured: From Signing of Informed Consent Form (ICF) up to Safety Follow Up (Up to Day 21)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Sep 2026
- Study start23 Sep 2026
- Primary completion27 Oct 2026 (estimated)
- Study completion27 Oct 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Cystic FibrosisStudies of the same condition, open and under way.
- More trials run by Vertex Pharmaceuticals IncorporatedThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 16 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Vertex Pharmaceuticals Incorporated
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07813039
- Sponsor's protocol ID
- VX25-581-002
- Status last verified
- Oct 2026
- First submitted
- 4 Sep 2026
- Last updated
- 19 Oct 2026
- Results posted
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No: Details on Vertex data sharing criteria and process for requesting access can be found at: https://www.vrtx.com/our-science/clinical-trials-data-sharing/