Lives unaffected by cystic fibrosis


Back to the Drug Development Pipeline

VX-121 + tezacaftor + VX-561

Phase Three

Phase Three

Therapeutic Approach

Restore CFTR Function

This program is studying a combination therapy combining three CFTR modulators. VX-121 and tezacaftor are CFTR correctors, a type of modulator designed to fix the defective CFTR protein so that it can move to the proper place on the cell surface. VX-561 is an altered form of the potentiator ivacaftor (Kalydeco®). Potentiators are drugs that facilitate the opening of the chloride channel on the cell surface to allow chloride and sodium (salt) to move in and out of the cell. VX-561, or deuterated ivacaftor, may be more stable in the body than regular ivacaftor, which would allow it to be taken once a day.


A phase 2 study to test the safety and effectiveness of VX-121 + tezacaftor + VX-561 in adults with CF was completed.

A phase 3 study is currently underway to test this triple combination therapy in people with CF who are 12 years and older. The study is for people with one copy of the F508del mutation and one copy of a minimal function mutation.


This program is sponsored by Vertex Pharmaceuticals. This program is being conducted within the Therapeutics Development Network (TDN).

Contact us about VX-121 + tezacaftor + VX-561 >