Resistance of mitochondrial DNA to cadmium and Aflatoxin B1 damage-induced germline mutation accumulation in C. elegans.

Mitochondrial DNA (mtDNA) is prone to mutation in aging and over evolutionary time, yet the processes that regulate the accumulation of de novo mtDNA mutations and modulate mtDNA heteroplasmy are not fully elucidated. Mitochondria lack certain DNA repair processes, which could contribute to polymerase error-induced mutations and increase susceptibility to chemical-induced mtDNA mutagenesis. We conducted error-corrected, ultra-sensitive Duplex Sequencing to investigate the effects of two known nuclear genome mutagens, cadmium and Aflatoxin B1, on germline mtDNA mutagenesis in Caenorhabditis elegans. Detection of thousands of mtDNA mutations revealed pervasive heteroplasmy in C. elegans and that mtDNA mutagenesis is dominated by C:G → A:T mutations generally attributed to oxidative damage. However, there was no effect of either exposure on mtDNA mutation frequency, spectrum, or trinucleotide context signature despite a significant increase in nuclear mutation rate after aflatoxin B1 exposure. Mitophagy-deficient mutants pink-1 and dct-1 accumulated significantly higher levels of mtDNA damage compared to wild-type C. elegans after exposures. However, there were only small differences in mtDNA mutation frequency, spectrum, or trinucleotide context signature compared to wild-type after 3050 generations, across all treatments. These findings suggest mitochondria harbor additional previously uncharacterized mechanisms that regulate mtDNA mutational processes across generations.

Understanding Use of Real-World Data and Real-World Evidence to Support Regulatory Decisions on Medical Product Effectiveness.

RWE has potential to provide efficient and relevant information on the effectiveness of medical products, complementing the data generated in clinical trials; however, how RWE can support regulatory decision-making is unclear, potentially limiting its use. The objective of this study was to identify and characterize instances where RWE was included in the evidence package to support the effectiveness of a medical product regulated by U.S. Food and Drug Administration. A retrospective landscape analysis was conducted to identify instances where RWE was submitted to support effectiveness through targeted review of white and gray literature and publicly available FDA reviews of medical products. Trained evaluators examined FDA reviews to determine if and how RWE contributed to regulatory decision-making regarding effectiveness. Evaluators identified 34 instances of RWE submitted between 1954 and 2020, where 26% of instances were for oncology, 18% for hematology, and 12% for neurology. Over 50% of the products were indicated for use in rare disease or pediatric populations. 82% of products where RWE was submitted received an orphan designation. RWE was included in the product label in 59% of instances. Stated reasons indicating why submitted RWE did not significantly contribute to regulatory decision-making included lack of pre-specification of study design and analysis as well as data reliability and relevancy concerns. While there is historical use of RWE to support medical product effectiveness for oncology and rare diseases, potential exists to leverage the strengths of RWE to support other therapeutic areas and capture outcomes that are most relevant to patients.