EHA 2023 – Crispr sets a date with the US regulator

With the FDA yesterday accepting a filing for Crispr Therapeutics/Vertex’s exa-cel the stage is set for the west’s first Crispr-edited therapy. Given how momentous this is, perhaps the biggest surprise is that no advisory committee meeting has been scheduled – though, as Sarepta found out, this could change. Exa-cel now carries Pdufa dates of 8 December for sickle cell disease, a use that has priority review, and 30 March 2024 for beta thalassaemia, which does not. Coincidentally, the companies are due to present data from these two uses’ pivotal trials at this weekend’s EHA meeting, having earlier dribbled out hints about efficacy on a patient-by-patient basis. Vertex yesterday said 16 of 17 sickle cell patients had achieved at least 12 months’ freedom from vaso-occlusive crises, the key among seven co-primary endpoints in the Climb SCD-121 trial. Meanwhile, in the thalassaemia Climb Thal-111 study, 24 of 27 evaluable subjects have hit at least 12 months’ transfusion independence, the most important of six co-primaries. Exa-cel treatment comes with the burden of chemotherapy preconditioning, and it is a relief that safety-wise there is nothing worse than the two patients with serious adverse events and one Covid death already disclosed.