Addressing Multiplicity in Retinal Sensitivity Analysis: An Alternative Approach to Assessing Gene Therapy Efficacy...

The purpose of this study was to propose an alternative statistical approach that addresses the issue of multiplicity in microperimetry data analysis, offering a more balanced and sensitive measure of the efficacy of gene therapy in inherited retinal diseases (IRDs).

We analyzed microperimetry data from a phase II trial of AGTC-501 in patients with X-linked retinitis pigmentosa (XLRP). The Macular Integrity Assessment (MAIA; CenterVue, Padova, Italy) device was used to evaluate test-retest repeatability. A binomial model was used to calculate the probability of ≥7 decibel (dB) improvements due to chance alone across a 68-locus grid. We proposed an alternative approach to detect changes using a threshold of ≥7 loci with ≥7 dB mean improvement.

Test-retest repeatability analysis showed a probability of < 5% for observing pointwise improvements ≥7 dB between 2 baseline visits. Applying the binomial distribution model, we found that the probability of observing improvements ≥7 dB in at least 7 unspecified loci purely by chance was 5.3%.

The proposed approach provides a balanced way to address multiplicity while maintaining reasonable statistical significance. Using ≥7 unspecified loci as the criterion for assessing sensitivity changes, offers a comprehensive assessment that can detect genuine treatment effects without being overly conservative.

This alternative statistical method has the potential to improve the evaluation of retinal sensitivity changes in gene therapy trials for IRDs, providing a more accurate measure of therapeutic efficacy and enhancing clinical decision making.