This paper analyses the allocation of R&D investments within rare diseases and identifies the characteristics of rare diseases that appear to lead R&D resources. Rare diseases affect less than 1 in 2000 citizens. With over 7000 recognised rare diseases and 350 million people affected worldwide, rare diseases are not so rare when considered collectively. Rare diseases are generally underserved by drug development because pharmaceutical industries consider R&D investments in rare diseases too costly and risky in comparison with the low expected returns due to the small population involved. We use data on rare diseases research from Orphanet along with academic publications per rare disease from bibliographic databases. We test the existence of inequalities in R&D investments within rare diseases and identify the disease characteristics that appear to lead R&D investments using dominance tools and bilateral tests. We show that rare diseases in children and with a smaller prevalence, such as ultra-rare diseases, are underserved by R&D. R&D investments appear to be concentrated in more profitable research areas with potentially larger sample size and adult population.

中文翻译：

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（In）-稀有疾病研发资源分配中的平等

本文分析了稀有疾病中R＆D投资的分配，并确定了可能导致R＆D资源的稀有疾病的特征。罕见疾病仅影响2000名市民中不到1名。全世界有7,000多种公认的罕见病和3.5亿人受到感染，因此，将各种疾病综合考虑，并不是那么罕见。药物开发通常无法为罕见疾病提供足够的服务，因为与由于人口少而导致的预期收益低相比，制药行业认为对罕见疾病的研发投资成本高，风险大。我们使用Orphanet的罕见疾病研究数据以及书目数据库中每种罕见疾病的学术出版物。我们测试R＆R中不平等的存在 在稀有疾病中进行D投资，并使用优势工具和双边测试来确定可能导致研发投资的疾病特征。我们发现，R＆D对儿童和流行率较小的罕见疾病（如超罕见疾病）的服务不足。研发投资似乎集中在利润更高的研究领域，可能有更大的样本量和成年人口。