Pfizer joined Novartis as the market leader in sickle cell disease when it acquired Global Blood Therapeutics last year. The US giant's Oxbryta may now move ahead following a clinical and regulatory setback for the Swiss major's Adakveo.

Even before a new law granted FDA authority to require studies be underway before accelerated approval, review divisions have, in some cases, given sponsors years of advance notice on expectations around study timing, according to a Pink Sheet review of NME accelerated approvals.

Recent financings, including the $150m launch of Pathalys and a planned $100m IPO for Mineralys, illustrate the reality of biopharma funding in 2023 – that having near-term clinical trial milestones are key to fundraising this year. Companies with dwindling cash are conserving the funds they have left.

FDA Commissioner Califf acknowledges that regulatory pathways for gene therapies are still being developed and that many factors outside of the modality impact agency requirements as he emphasized the need for long-term follow up due to the unknowns of gene modification.