Randomised non-comparative trial
A randomised non-comparative trial, RNCT (or also non-comparative randomised trial{{cite journal | last=Sundar | first=Shyam | last2=Pandey | first2=Krishna | last3=Mondal | first3=Dinesh | last4=Madhukar | first4=Major | last5=Kamal Topno | first5=Roshan | last6=Kumar | first6=Ashish | last7=Kumar | first7=Vinod | last8=Kumar Verma | first8=Deepak | last9=Chakravarty | first9=Jaya | last10=Chaubey | first10=Rahul | last11=Kumari | first11=Poonam | last12=Rashid | first12=Md. Utba | last13=Maruf | first13=Shomik | last14=Ghosh | first14=Prakash | last15=Raja | first15=Sheeraz | last16=Rode | first16=Joelle | last17=den Boer | first17=Margriet | last18=Das | first18=Pradeep | last19=Alvar | first19=Jorge | last20=Rijal | first20=Suman | last21=Alves | first21=Fabiana | title=A phase II, non-comparative randomised trial of two treatments involving liposomal amphotericin B and miltefosine for post-kala-azar dermal leishmaniasis in India and Bangladesh | journal=PLOS Neglected Tropical Diseases | volume=18 | issue=6 | date=2024-06-20 | issn=1935-2735 | pmid=38900786 | pmc=11189210 | doi=10.1371/journal.pntd.0012242 | doi-access=free | page=e0012242}}), is a type of clinical trial where participants are randomised to different conditions (arms), but where the primary analysis involves comparing each arm separately to a historical control, predefined benchmark or something else, with no formal comparison between the two arms.{{cite journal | last=Msaouel | first=Pavlos | title=The curious rise of randomised non-comparative trials | journal=Significance | volume=22 | issue=3 | date=2025-03-28 | issn=1740-9705 | doi=10.1093/jrssig/qmaf029 | pages=40–44 | url=https://academic.oup.com/jrssig/article/22/3/40/8099023 | access-date=2025-04-17| url-access=subscription }}
The study design appears to have arisen in oncology, where single-arm studies are not unusual. It promises reduced sample size requirements. An RNCT acts like multiple single-arm designs run concurrently. A review found RNCTs dating back to 2002, and having been used in high-profile oncology studies and also beyond oncology.{{cite journal | last=Sherry | first=Alexander D. | last2=Msaouel | first2=Pavlos | last3=Ludmir | first3=Ethan B. | title=A meta-epidemiological analysis of post-hoc comparisons and primary endpoint interpretability among randomized noncomparative trials in clinical medicine | journal=Journal of Clinical Epidemiology | volume=175 | date=2024 | doi=10.1016/j.jclinepi.2024.111540 | page=111540 | url=https://linkinghub.elsevier.com/retrieve/pii/S0895435624002968 | access-date=2025-04-17| url-access=subscription | doi-access=free }}
The design has been criticised by statisticians. It is unclear what benefit randomisation adds compared to running separate single-arm studies. Pavlos Msaouel described the use of the word "randomisation" as merely being "talismanic" in a 2025 article, it leading readers to think the study has the benefits of a randomised controlled trial (RCT). While the point of an RNCT is not to have a comparison between arms, about half of reported RNCTs still reported some sort of comparison.