The Open EPPI corpus comprises 151 full-text 001 papers annotated by domain experts for entity 002 mentions, protein-protein interactions (PPIs), 003 and normalisation of entities to publicly avail-004 able ontologies. The corpus is publicly avail-005 able at [ANON]. We benchmark recent nested 006 NER and relation extraction models. Results 007 show that, although existing nested NER mod-008 els achieve good performance on outermost 009 and innermost entity mentions, they struggle 010 with other types of nested mentions. Bench-011 mark results for relation extraction show sub-012 stantial room for improvement with precision 013 under 70 and recall around 40 to 52 . 014