University of Kansas Medical Center

RETRIAL-Mental Health: - PWCF age 6 years and up (if age is < 12 years old, the PWCF's caregiver will complete daily diaries and surveys; see "Caregiver Participant Inclusion Criteria" below) - Eligible for VTD and intending to take it - Experienced new or worsening mental health symptoms after initiating ETI, which led to one of the following changes in treatment to currently taking: 1. No modulators 2. A modulator other than ETI 3. A flipped dose of ETI 4. A reduced dose of ETI - Willing to delay first VTD dose for short period of time to complete the Baseline assessments - Has access to a smart device (phone, tablet, etc.) capable of receiving messages with survey links - Is English-speaking. RETRIAL-LIVER: - A person with CF age 6 years and up - Eligible for VTD and intending to take it - Experienced drug-induced liver injury (as defined by local care team) after initiating ETI, which led to one of the following changes in treatment to currently taking: 1. no modulators; or 2. a modulator other than ETI; or 3. a reduced or altered dose of ETI; - Willing to delay first VTD dose for short period of time to complete the Baseline assessments - Has access to a smart device (phone, tablet, etc.) capable of receiving messages with survey links - Is English-speaking.

RETRIAL-Mental Health: - Cannot access VTD - Currently, or prior history of, taking VTD - Unable or unwilling to follow protocol - If <12 years old, having another <12-year-old person in the same household consented into the study - Is actively listed on any transplant list, or within 3 months post-transplant surgery - Is currently pregnant (test not required) - Anticipated change in CF Care Centers in the next 6 months - Any situation that, in the opinion of the Investigator, would compromise the safety of the patient or the quality of the data. RETRIAL-LIVER: - Cannot access VTD - Currently, or prior history of, taking VTD - Unable or unwilling to follow protocol - If <12 years old, having another <12-year-old person in the same household consented into the study - Any severe, decompensated liver disease (e.g. Child-Pugh, Class C) - Is actively listed on any transplant list, or within 3 months post-transplant surgery (any organ), or history of liver transplant - Is currently pregnant (test not required) - Anticipated change in CF Care Centers in the next 6 months - Any situation that, in the opinion of the Investigator, would compromise the safety of the patient or the quality of the data. Caregiver Participant: Inclusion Criteria: - Is a primary, daily caregiver of a person with CF under the age of 12 enrolled in the study - Has access to smart device (phone, tablet, etc.) capable of receiving messages with survey links - Is able to read and complete surveys and Daily Diary in English. Exclusion Criteria: - Any situation that, in the opinion of the Investigator, would compromise the safety of the patient or the quality of the data.