Related Experiment Video
Updated: Feb 2, 2026

Prospective, Randomized, and Controlled Study of a Human Umbilical Cord Mesenchymal Stem Cell Injection for Treating Diabetic Foot Ulcers
Published on: March 3, 2023
Monthly Versus Treat-and-Extend Ranibizumab for Diabetic Macular Edema: A Prospective, Randomized Trial
Background And Objective:
Compare fixed monthly dosing of ranibizumab to treat-and-extend (T&E) ranibizumab during a period of 24 months for diabetic macular edema (DME) treatment.
Patients And Methods:
Single-center, randomized, prospective pilot study that included 20 eyes of 20 subjects. Patients' best-corrected visual acuity (BCVA) was less than or equal to 20/40 and central foveal thickness on spectral-domain optical coherence tomography was greater than 325 µm. Intravitreal ranibizumab was dosed monthly or by protocol-specified treat-and-extend. Primary outcome was mean change in mean BCVA. Institutional review board approval was obtained.
Results:
At month 24 (M24), there was a mean 8.3-letter gain in the monthly treatment group and an 8.5-letter gain in the T&E group (P = .082; 90% confidence interval). The average change from baseline BCVA was not statistically significantly different at any timepoint. At M24, the median number of injections in the monthly and T&E groups were 22.5 and 18.5, respectively (P = .287).
Conclusions:
Visual acuity with monthly dosing appears equivalent to T&E dosing during the course of 24 months. There was a trend toward a lower injection burden in the T&E arm. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:e191-e197.].
Related Concept Videos
Clinical Trials: Overview
Trial and Error and Algorithm
Clinical Trials
There are four phases in a clinical trial. A phase one...
Random Error
Random Variables
Uppercase letters such as X or Y denote a random variable. Lowercase letters like x or y denote the value of a random variable. If X is a random variable, then X is written in words, and x is given as a number.
For example, let X = the...
Randomized Experiments
Simple randomization
Simple...

