The recent NICE consultation on methods for health technology evaluation (HTE) outlined plans to include guidance on the role of real-world evidence (RWE) in HTE. This is particularly pertinent for indications where the evidence base consists of a single arm trial (SAT) design, such as orphan diseases. This study reviewed the influence of additional evidence submitted to NICE for orphan oncology products. A search for NICE HTEs was carried out using the IQVIA HTA Accelerator™. HTEs for orphan oncology products with a final decision in 2016-June 2021 were included, excluding resubmissions and extensions. Evidence was stratified by submission packages with randomised and non-randomised design, with or without RWE. Thirty-two decisions for orphan oncology products were made by NICE between 2016-2019. Of these, 25 (78%) submitted RCT evidence compared to 7 (22%) supported by SAT evidence. A lower proportion of RCT HTEs submitted RWE compared to SAT HTEs (32% vs 86%). All SAT HTEs received a positive recommendation with (57%) or without (43%) restrictions, irrespective of submitting RWE. All negative decisions were observed for RCT HTEs with no RWE (16%), with the remaining receiving a positive recommendation with (52%) or without (32%) restrictions. Overall, the proportion of positive recommendations were higher for HTEs submitting RWE (100%) compared to HTEs not submitting RWE (78%). HTEs submitting additional RWE are more likely to receive a positive recommendation, irrespective of the trial design for the core evidence base. The value of RWE seems to be established in HTEs relying on SAT evidence, whereas for RCT HTEs, there may be an opportunity to achieve higher rates of positive decisions by including additional RWE evidence. A closer examination of the role RWE played in the reviewed HTEs is ongoing.