Clinical trials that investigate therapies for rare gynaecological cancers (RGC) are essential to provide evidence-based data towards new effective and safe treatments, however, they present unique challenges. The main objective of this narrative review is to summarize completed phase III clinical trials investigating therapies for RGC and to discuss the outcomes of these trials. PRISMA guidelines were used to report the steps of the review. We searched the WHO's International Clinical Trials Registry Platform, clinicaltrials.gov and PubMed/Medline for publications reporting results from clinical trials on RGC including at least one medication. From 31 identified phase III clinical trials, 13 were still ongoing, four were terminated and just eight (25.8 %) had posted results and/or publications. The latter completed trials were mostly multi-center and located in at least two continents, participants were mainly adults, and the recruitment period varied from about 2.5 to 10.5 years. Allocation was randomized with parallel assignment in 7 out of 8 trials, while only one trial had double masking. The most common primary outcome measure was progression-free survival (PFS), followed by overall survival (OS). Patient-reported outcomes were secondary outcome measures in four completed trials, assessing quality of life by various questionnaires. Most of the trials did not meet their primary endpoints. By highlighting the scarcity of clinical trials on RGC, our findings further emphasize the need for designing, conducting and sustaining phase III clinical trials to investigate innovative therapies for these conditions and report meaningful outcome measures.
