Reporting preclinical gene therapy studies in the field of Niemann-Pick type C disease according to the ARRIVE guidelines.

The lack of essential information when reporting animal studies causing lower reproducibility has been stressed for decades. The ARRIVE (Animal Research: Reporting of In Vivo Experiments) guidelines were first published in 2010, to improve reporting of animal research, making in vivo studies more transparent thereby improving the scientific quality. Regardless of an endorsement from the scientific community, there is still a continuous need to improve animal research reporting, which unfortunately also is the case in the field of Niemann-Pick type C disease (NPC). NPC is a lipid storage disorder, caused by mutations in either the Npc1 or Npc2 gene. Despite years of research, no cure for this fatal disease exists. In 2020, an updated version of the ARRIVE guidelines (ARRIVE 2.0), was published, describing the ten most essential elements to be included when reporting pre-clinical studies. Here we systematically reviewed the compliance with the ARRIVE guidelines using the "ARRIVE Essential 10" checklist in a series of pre-clinical studies investigating gene therapy as a treatment strategy for NPC. None of the reviewed papers fulfilled the ARRIVE 2.0 guidelines. Information regarding sample size, randomization, blinding, and statistical methodology was lacking. Hopefully, the newly updated ARRIVE guidelines will aid researchers in planning and publishing in vivo experiments in the future. More awareness of the importance of including these essential items is needed, both from editors, reviewers and researchers, for complete endorsement of the ARRIVE guidelines in the scientific community.