Correlation of predicted to observed drug–drug interaction in ggplot2 or tidyverse

[bhim.chaudhari]

Hi Helping Hands,
I am trying to plot figure as attached. Looking for your support to get a plot, mainly facing issue with dynamic upper and lower margin.
I have a Dummy Case:

• Conducted a clinical study and physiologically based pharmacokinetic (PBPK) simulation to evaluate a potential drug-drug interaction.
  Outcome:
• Clinically Observed: AUC treated to AUC control Ratio: 1.10
• PBPK Predicted AUC treated to AUC control Ratio: 1.20

To assess the accuracy and relevance of the prediction, I want to generate a plot comparing the observed and predicted AUC ratios. The plot should include:

• Identity Line: Represents perfect prediction (Observed = Predicted).
• 2-Fold Error Margins: Upper and lower bounds at ±2-fold deviation from the identity line.
• Dynamic Boundaries (need to be cheeked):
  • Limit is calculated using the formula:
    Limit=[Variability+2×(Observed AUC Ratio−1)]/Observed AUC Ratio
  • Dynamic Upper Bound = Limit × Observed AUC Ratio
  • Dynamic Lower Bound = Limit ÷ Observed AUC Ratio

For this case:

• Variability is set to 1.25, and Observed AUC Ratio = 1, the dynamic bounds align with the standard bioequivalence limits of 0.80 to 1.25, which corresponds to the conventional ±20% range used in bioequivalence testing.
• If Variability = 1, it implies no variability, and the dynamic bounds collapse to the identity line.
  I am seeking your support to plot as figure.

[mduvekot]

What have you tried so far?