Synthesis and Evaluation of Ivacaftor Derivatives with Reduced Lipophilicity
Bibliographic record
Abstract
High Resolution Image Download MS PowerPoint Slide Mutations in the unique ATP-binding cassette anion channel, the cystic fibrosis conductance regulator (CFTR), lead to the inherited fatal disease known as cystic fibrosis (CF). Ivacaftor enhances channel gating of CFTR by stabilizing its open state and has been approved as monotherapy for CF patients with CFTR gating mutations (e.g., G551D) and as part of combination therapy with lumacaftor for CFTR folding mutations (e.g., ΔF508). However, in the latter context, ivacaftor may destabilize folding-rescued ΔF508-CFTR and membrane-associated proteins and attenuate lumacaftor pharmacotherapy. Here, we tested the hypothesis that the high lipophilicity of ivacaftor may contribute to this effect. We describe the synthesis of three glutamic acid ivacaftor derivatives with reduced lipophilicity that bear different charges at neutral pH (compounds 2, 3, 4 ). In a cellular ion flux assay, all three restored G551D-CFTR channel activity at comparable or better levels than ivacaftor. Furthermore, unlike ivacaftor, compound 3 did not attenuate levels of folding-rescued ΔF508 at the cell surface. Molecular modeling predicts that the increased polarity of compound 3 allows engagement with polar amino acids present in the binding pocket with hydrogen bonding and ionic interactions, which are collectively higher in strength as compared to hydrophobic interactions that stabilize ivacaftor. Overall, the data suggests that reduced lipophilicity may improve the efficacy of this class of CFTR potentiators when used for folding-rescued ΔF508-CFTR.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".