MTD
Pronunciation: M-T-D
Also written as: MTD — maximum tolerated dose
Maximum tolerated dose, the highest treatment dose associated with acceptable toxicity.
Full Definition
Maximum tolerated dose (MTD) is the highest dose of a therapeutic agent that can be administered without causing unacceptable or dose-limiting toxicity in a defined percentage of patients, typically determined through dose-escalation studies. MTD is traditionally established in phase I clinical trials using various dose-escalation designs such as 3+3, continual reassessment method, or Bayesian optimal interval designs. The concept assumes that higher doses provide greater efficacy while accepting a defined level of toxicity. However, modern drug development increasingly recognizes that MTD may not always represent the optimal biological dose, particularly for targeted therapies and immunotherapy.
Usage
Usage note: MTD determination requires careful definition of dose-limiting toxicity criteria and observation periods.
In Context
- "The MTD was established at 400 mg daily with dose-limiting thrombocytopenia." — Phase I dose-escalation study
- "No MTD was reached at the highest planned dose level of 800 mg." — Dose-escalation study results