Figure 1. MS analysis of CFTR modulator intracellular concentrations during treatment and washout phases in HBE (F508del/F508del) cells.
Ivacaftor continually accrued during the treatment period, and only moderately declined during the washout period. A) Lumacaftor or Ivacaftor was measured in treated (Luma/Iva) or untreated (DMSO) samples. Lumacaftor displayed minimal accrual over the treatment phase and was undetectable within 7 days of washout. B) Tezacaftor or Ivacaftor was measured in treated (Teza/Iva) or untreated (DMSO) samples. Tezacaftor also only accrued to a minimal extent during the treatment phase and diminished throughout the two-week washout phase. Both tezacaftor and lumacaftor concentrations were rapidly eliminated from CF-HBEs within 1 day of beginning washout (day 15), while ivacaftor levels were still increasing to maximum after treatment cessation. *, + indicate level of significance between vehicle and treatment groups at the specified time point.