The drug maker said the program would allow for continued reimbursement when patients change insurance plans. A Sangamo-partnered gene therapy for hemophilia A is also in the works.

There are pending requests to add 13 candidates to the tropical diseases that qualify for a priority review voucher, according to a Pink Sheet analysis, as FDA Commissioner Robert Califf faces congressional pressure on the years since the list's last update.

Private Company Edition: Regeneron launched a $500m venture fund and Canaan added $100m, bringing the venture firm’s recent total to $1bn-plus. Also, incubators plan to grow over the next decade and in recent financings Avenzo raised $150m and Nvelop launched with $100m.

The CEOs of bluebird bio and CRISPR Therapeutics hope to inspire investor confidence that their gene-based therapies for sickle cell disease and beta thalassemia will be widely reimbursed in the US and EU.