A patient-specific drug safety-efficacy index was developed that combined objective clinical trial information about dose-related efficacy and toxicity with subjective perspectives on efficacy-toxicity trades.
Patient preferences were systematically assessed using the probability tradeoff technique (PTT). Toxicity ranges over which a drug's efficacy exceeded the patient's minimally acceptable efficacy represented ranges of “surplus efficacy.” These can be related to the dose interval in which a drug delivers this surplus efficacy. Seventy surplus efficacy functions (for 7 hypothetical drugs and 10 hypothetical preference curves) were simulated.
The analysis showed that index values change markedly by dose and patient preference, suggesting that different patients will benefit from different drugs depending on the dose prescribed and each patient's subjective assessment of the efficacy/toxicity tradeoff. In most situations, drugs achieve positive surplus efficacy only over limited dose ranges. The model was sensitive to different preference curves and discriminated well among drugs with different efficacy or safety profiles.
This index provides a new, systematic approach to choosing a specific therapeutic intervention and dosage, when known risks and benefits are reconciled against patient-specific preferences among an array of therapeutic alternatives.